Aqueous solution and method for repair of pollutants in

Abstract

A treatment method for the removal and / or remediation of contaminants in a contaminating gas comprising flowing a stream of contaminating gas through a conduit, treating the flowing stream of contaminating gas by injecting droplets of a liquid treatment composition comprising a total of 35-55% by weight of one or more hydroxides into the stream of contaminating gas flowing in the conduit, injecting water into the mixed stream of the stream of contaminating gas and the liquid treatment composition in the conduit downstream of the injection of the liquid treatment composition into the conduit such that the liquid treatment composition is mixed into the contaminating gas in the flow stream and remedies contaminants in the contaminating gas, a flow stream of treated pollution gas is separated from any residual amount of liquid treatment composition, water, and precipitates in a separator.

Description

Technical Field

[0001] The present disclosure relates to improved aqueous treatment solutions and treatment methods for remediating pollutants in polluted gases (including natural gas, exhaust gases from fossil fuel combustion, etc.) using aqueous treatment solutions, wherein the pollutants include sulfur-containing compounds (including H2S, mercaptans, thiophenes) and BTEX (benzene, toluene, ethylbenzene, xylenes), etc., as well as other pollutants (including CO2, SO2, metals, salts, etc.). More specifically, the present disclosure relates to such treatment solutions and treatment methods, which can be used as new treatments or pretreatments for polluted gases, thereby remediating a variety of pollutants in the gases to significantly reduced levels in an efficient and economical manner. Background Art

[0002] Sulfur-containing compounds, including hydrogen sulfide (H2S), mercaptans, thiophenes, and BTEX, have long been considered undesirable contaminants in contaminated fluids, especially hydrocarbon fluids such as crude oil and natural gas. H2S is a particularly undesirable contaminant because it is highly toxic, corrosive, etc., and hydrocarbon fluids should generally contain less than 5 ppm of H2S. The remediation of H2S in hydrocarbon fluids has long been and remains a very important focus of the petroleum industry worldwide, and governments around the world generally stipulate that the content of H2S in natural gas should not exceed 4-5 ppm in order to be sold or used.

[0003] Treating contaminated liquids (e.g., crude oil) can be challenging, but there are many known treatment compositions and treatment methods for this purpose, including some previously proposed by one of the present inventors, such as those disclosed in International Patent Application Nos. PCT / US2018 / 050913 and PCT / US2018 / 064015, the entire contents of which are incorporated herein by reference. In these methods previously proposed by one of the present inventors, the treatment composition can be added directly to the contaminated liquid or combined with the contaminated liquid so that the chemicals (primarily hydroxides) contained in the treatment composition can react with the contaminants to remediate the contaminants into other less problematic non-toxic compounds that can remain in the treated liquid or precipitate out of the treated liquid.

[0004] As disclosed in PCT / US2018 / 050913, a scheme for treating contaminated liquids previously proposed by one of the present inventors includes an aqueous treatment composition mainly containing high concentrations of one or more hydroxides (e.g., sodium hydroxide (NaOH) and potassium hydroxide (KOH), etc.) (e.g., the hydroxides account for a total of 35-55% by weight of the treatment solution, preferably at least 45% by weight), which effectively reacts with H2S to convert it into a non-toxic substance. According to the recently proposed scheme, this treatment solution is highly alkaline, with a pH value of 13-14. In this treatment method, a relatively small dose of treatment solution (e.g., at a standard dosage rate of 0.25-6.0 mL of treatment solution / liter of liquid to be treated, preferably a standard dosage rate of 1.0-5.0 mL of treatment solution / liter of liquid to be treated, which is equivalent to about 125-3000 ppm of hydroxide in the liquid to be treated) is added to the hydrocarbon-based liquid or aqueous solution to be treated. A particularly suitable dosage rate depends on a variety of factors, provided that the hydroxide in solution effectively remediates H2S and other sulfur-containing compounds to acceptable levels in a relatively short period of time (e.g., 15 minutes to several hours) and does not adversely affect the hydrocarbon-petroleum-based fluid or the contaminated aqueous solution in any significant manner.

[0005] Significantly, unlike previously known H2S scavenging compositions comprising triazines or formaldehyde and methods of remediating H2S and other contaminants in liquids, including crude oil, the previously proposed treatment methods comprising the treatment compositions are irreversible with respect to the H2S and other contaminants being remediated. Furthermore, and significantly, the standard dosage of the above-described treatment compositions is suitable for remediating contaminated liquids, including crude oil, which contain large quantities of various contaminants, which is also very different from previously known H2S scavenging compositions comprising triazines or formaldehyde, which require more specific dosage rates based on the amount of H2S and other contaminants to be removed. Thus, except for unusual liquids containing very large quantities of contaminants, it is generally not necessary to adjust the dosage based on the specific amount of contaminants contained in the liquid to be treated, and the treatment method is not adversely affected if the amount of contaminants in the liquid to be treated increases dramatically at times during the treatment method.

[0006] As disclosed in PCT / US2018 / 064015, another approach previously proposed by one of the present inventors involves the use of a water-based treatment composition similar to the composition disclosed in PCT / US2018 / 050913, but additionally comprising an appropriate amount of an organic acid (e.g., fulvic acid and humic acid) added to the liquid to be treated, whether it is a hydrocarbon-based liquid or a contaminated aqueous solution, at a dosage rate that generally results in an organic acid concentration in the liquid to be treated within the normal range of 0.01-10 ppm (preferably 0.1-3 ppm). The organic acid (e.g., fulvic acid and humic acid) is effective in binding to the contaminants being remediated and retaining them in the treated liquid without forming any precipitation, while the contaminated liquid is treated, transported and / or stored for a period of time, such as hours, days or weeks, before the treated liquid is further processed in a refinery or the like. A small amount, such as less than 2 wt %, of an antiscalant, such as monoethanolamine (MEA), may be present in the treatment method / composition.

[0007] Fulvic acid is actually a family of organic acids, but is generally considered to be 1H,3H-pyrano[4,3-b][1]benzopyran-9-carboxylic acid, 4,10-dihydro-3,7,8-trihydroxy-3-methyl-10-oxo-; 3,7,8-trihydroxy-3-methyl-10-oxo-1,4-dihydropyrano[4,3-b]chromene-9-carboxylic acid, with an average chemical formula of C 135 H 182 O 95 N5S2, molecular weights are usually in the range of 100 g / mol to 10,000 g / mol. Somewhat similarly, humic acid is a mixture of several molecules, some of which are based on a motif of aromatic nuclei with phenolic and carboxyl substituents linked together, a typical structure is shown in the figure below. The molecular weight (size) of humic acid is usually much greater than that of fulvic acid and can range from 50,000 g / mol to over 500,000 g / mol.

[0008]

[0009] The treatment composition and method according to this previously proposed scheme include a standard dosage of the treatment composition, which generally corresponds to the standard dosage of the first previously proposed scheme described above. This previously proposed treatment composition and method are also advantageously irreversible, and the standard dosage of the above treatment composition is suitable for remediation of contaminated liquids, including crude oil, which contain a large number of various contaminants.

[0010] Although the solution previously proposed by one of the present inventors for treating contaminated liquids is more effective, cost-effective and practical than previously known treatment compositions and treatment methods, there is still a need for improvement.

[0011] For a variety of reasons, treating contaminated gases is generally more challenging than treating contaminated liquids. Although there are many known treatment compositions and treatment methods for treating contaminated gases, in many cases, conventional treatment compositions and treatment methods are not effective enough in remediating contaminated gases in a practical, cost-effective manner. For example, there are many known natural gas reserves in the world that are severely contaminated by H2S as well as other significant contaminants (including other types of sulfur-containing compounds, carbon dioxide (CO2), ammonia (NH3), water (H2O), salts (such as sodium chloride (NaCl)), nitrogen (N2), crude oil, various solid materials (including organic matter, etc.), which have proven to be the most challenging). Using conventionally known treatment compositions and treatment methods, it is impossible to fully remediate such highly contaminated natural gas in a practical, cost-effective manner to make the natural gas suitable for sale or use. Accordingly, many known natural gas reserves and existing natural gas wells are not used, but remain unexploited or closed.

[0012] With respect to treating contaminated gases, including natural gas, one of the present inventors has previously proposed treatment compositions and treatment methods for this purpose in U.S. Pat. No. 10,913,911 B2 (the '911 patent) and U.S. Pat. No. 11,549,064 (the '064 patent), the contents of which are incorporated herein by reference. The '911 patent discusses a variety of reasons why treating contaminated gases is more complicated than treating contaminated liquids (e.g., crude oil and contaminated aqueous solutions), even when the primary contaminant to be remediated in the gas is H2S, which is the primary contaminant to be remediated in crude oil. The reasons primarily include some significant complexities associated with continuously processing large volumes of contaminated natural gas, and thus treatment compositions and methods for treating contaminated liquids cannot be directly applied to treating contaminated gases. For example, in addition to H2S, contaminated gases (e.g., natural gas) typically contain large amounts of other contaminants (e.g., carbon dioxide (CO2), nitrogen (N2), water (H2O), sodium chloride (NaCl), etc.), which may result in very inefficient gas processing methods, including the tendency of some contaminants (e.g., salts) to precipitate from the contaminated natural gas as it is processed, which may easily clog components of the processing system and adversely affect the processing methods, resulting in significant costs and inefficiencies. In addition, the properties of contaminated gases, including natural gas, are very different from those of crude oil and other liquids, including the fact that the volume value of contaminated gases (e.g., natural gas) is much lower than that of crude oil, for example, natural gas is typically discharged continuously from a well at a relatively high rate, pressure, and volume of up to millions of cubic feet per well per day, and the handling and processing of contaminated gases is necessarily very different from that of liquids, which creates additional complexities in the processing of these contaminated gases. For example, a treatment method for remediating a contaminated gas (e.g., natural gas) may only allow the treatment composition and the contaminated gas to be in contact for a few seconds or less, as opposed to the treatment of a contaminated liquid, which may simply involve adding an appropriate amount of the treatment composition to the contaminated liquid and then allowing the liquids to mix and react together for an appropriate time until the H2S and other contaminants in the liquid are remediated to safe, acceptable levels.

[0013] As discussed in the '911 patent and the '064 patent, water-based treatment compositions, such as those disclosed in PCT / US2018 / 050913 and PCT / US2018 / 064015 and the '911 and '064 patents, can be used to remediate H2S, CO2, and other problematic contaminants in gas to safe levels, but the natural gas may first need to be treated to remove other contaminants, including salts and water, so that remediation of H2S, CO2, and other problematic contaminants can be performed continuously and efficiently. According to the inventors' previously proposed scheme, the treatment compositions disclosed in the '911 patent and the '064 patent are water-based and similar to the treatment compositions disclosed in PCT / US2018 / 064015. It includes a high concentration of hydroxide for remediation of H2S, CO2, etc., and a smaller amount of organic acids (such as fulvic acid and humic acid) to prevent the formation and release of precipitates from the treated gas, and may further include a chelating agent (such as ethylenediaminetetraacetic acid (EDTA)), a surfactant (such as sodium dodecyl sulfate) and a buffer (such as potassium carbonate, etc.), the chelating agent can increase the efficiency of the hydroxide in remediating H2S and other contaminants, and help to make the remediation of H2S irreversible. A certain amount of this treatment composition can be placed in a reaction chamber or tower, and the natural gas can be bubbled through the treatment composition, whereby the H2S, CO2 and some other contaminants in the natural gas will be remediated while causing little or no precipitate to form and be released from the treated gas. However, before this remediation step, the treatment method may require additional preliminary treatment steps and equipment for removing water, salts, etc. from the natural gas before the natural gas reacts with the treatment composition. When the gas reacts with the treatment composition, if salts are present, the salts are likely to precipitate from the treated gas, and if salt precipitation is present, it will cause blockages and other problems that will make this part of the treatment method inefficient. Water in natural gas typically has salts dissolved therein and can undesirably dilute the treatment composition.

[0014] The treatment compositions and methods previously proposed by the inventors for remediating contaminants in gases have proven to be more practical and cost-effective in fully remediating H2S and other contaminants in gases (e.g., natural gas) than previously known treatment compositions and treatment methods. Like the solutions proposed by the inventors for remediating H2S and other contaminants in liquids, these treatment compositions and methods for remediating contaminants in gases irreversibly remediate H2S and other contaminants in gases, and standard doses of the treatment compositions are advantageous and effective for remediating contaminants of various contents. However, the treatment solutions and treatment methods previously proposed for remediating contaminated gases still need to be improved. For mixtures of contaminated gases and contaminated fluids including gases, it remains a huge challenge in the art to remediate H2S, CO2 and other contaminants therein to suitable safety levels in a practical, cost-effective manner. Summary of the invention

[0015] The present inventors have further studied the treatment of contaminated fluids (including liquids, gases and mixtures thereof) and developed new treatment solutions / compositions and treatment methods that can be used to remediate contaminated gases and very effectively, efficiently and economically remediate and / or remove essentially all types of pollutants, including hydrogen sulfide H2S, carbon dioxide (CO2), ammonia (NH3), water (H2O), salts (e.g., sodium chloride (NaCl)), nitrogen (N2), etc.), reducing the pollutants contained in the contaminated gases to significantly reduced levels in a very effective and cost-effective manner.

[0016] The first discovery of the present inventors relates to the treatment of polluted gases. These gases include natural gas from wells, which may contain large amounts of salts, CO2, H2S, NH3, SO2, other sulfur-based pollutants (including mercaptans and thiophenes) and metals, natural gas that has been partially treated according to the first discovery discussed herein by the present inventors, combustion gases of fossil fuels from various industries (including power plants) (usually with high concentrations of CO2 and SO2), gas streams including water vapor containing salts and metals, etc. In particular, the present inventors have found that the unique water scrubbing according to the present invention can be used very effectively and efficiently as a treatment or pretreatment method for significantly reducing the amount of various pollutants in the polluted gas, so that the treated gas can be used directly, or further treated and / or processed according to specific requirements.

[0017] The inventors have determined that if the water used in the water wash through which the contaminated gas is bubbled or otherwise contacted for treatment is modified to be alkaline by the addition of one or more alkaline materials (including hydroxides), the pH is raised to above 8, preferably in the range of above 8 to about 11, such alkaline water wash is surprisingly very effective in removing a large portion of the contaminants from the contaminated gas in a relatively simple treatment process, wherein the gas is bubbled or otherwise passed through the alkaline water wash with a relatively short contact time (e.g., in the range of 0.5-10 seconds). The water wash solution may contain a total of about 15-25% by weight of one or more hydroxides for raising the pH of the solution to 11, but the specific weight % will depend on the specific hydroxide used and the desired results. The inventors have experimented with this treatment method using an alkaline water wash according to the present invention and have found that it is surprisingly very effective in removing and / or remediating most salts, CO2, H2S, SO2, other sulfur-based pollutants (including mercaptans and thiophenes) and metals from contaminated gases, and that it can be effectively used to remove and / or remediate most pollutants from a variety of contaminated gas streams (including highly contaminated gas streams) in a practical, cost-effective manner if the alkaline water wash solution is replaced or re-strengthened regularly to maintain its potency / effectiveness.

[0018] Water is generally effective for removing salts from polluted gases because salts are readily soluble in water and when the gas is in contact with water in a water wash, salts easily enter the water from the gas. Both potable and non-potable water can be used in the water wash, although potable water is preferred because the water used should initially have a low salt content so that before the water becomes saturated with salts, it can absorb more salts from the polluted gas, resulting in higher efficiency. However, the inventors have found that if the wash water is made alkaline with a pH above 8 by adding an alkaline substance (e.g., hydroxide), then the water wash becomes very effective in removing substantially all salts from the gas. As the pH of the wash solution increases to above 10, it also becomes very effective to remove and / or remediate a large amount of H2S and other sulfur-based pollutants, CO2, metals, and substantially all other pollutants from the gas. For example, the present inventors have found that if the pH of the water wash is raised to a level of about 11 by adding an alkaline substance (e.g., hydroxide), and if a gas highly contaminated with H2S, SO2, CO2, salts, etc., is passed through the alkaline water wash, the appropriate contact time being at least 0.5-10.0 seconds, preferably at least 1.0 seconds, then: 1) substantially all of the salts enter the water wash from the gas and are precipitated out of the alkaline water wash; 2) many of the sulfur-based contaminants in the gas, including H2S, SO2, mercaptans, and thiophenes, are removed by contact with the alkaline substance (e.g., hydroxide) added to the water wash. 3) Many carbon-based pollutants in the gas, including CO2 and CO, are remediated by reacting with alkaline substances (such as hydroxides) added to the water wash and then precipitated from the gas / alkaline water wash, for example, in the form of carbonate crystals; and 4) Many metal pollutants in the gas also react with alkaline substances (such as hydroxides) added to the water wash and can then be precipitated from the gas / alkaline water wash. If the content of H2S and CO2 in the gas is about 30,000 ppm each before the water wash, then these respective contents can be reduced to about 10,000 ppm or less after passing through the alkaline water wash. Based on the high pH value, the alkaline water wash solution can also effectively kill any bacteria that may be contained in the contaminated gas, although of course antibacterial agents can also be added to the water wash. Some known antibacterial agents include silicates, such as potassium silicate (K2SiO3), copper sulfate (CuSO4), barium, etc. Typically, when a sufficient amount of contaminated gas is bubbled through or otherwise contacted with the water wash solution and the contaminants in the gas are remediated, a significant amount of solid precipitate may be released from the water wash solution. In addition, the contact time between the contaminated gas and the water wash solution may be controlled based on the volume and pressure of the contaminated gas passing through the water wash solution, the size of the reaction chamber and the amount of water wash solution contained therein, the means provided in the reaction chamber for interrupting the flow of the contaminated gas through the water wash solution, and the like.

[0019] In the new invention, the pH of the water wash can be increased to above 11 by adding a larger amount of alkaline material (e.g., hydroxide), and this alkaline water wash solution is still included in the present invention because it can also be very effective in removing most of the pollutants from the polluted gas, which is consistent with the purpose of the present invention. However, as a practical matter of cost, increasing the pH to above 11 requires proportionally much more of this material than increasing the pH of the water from about 7 to 11, so an upper limit of pH of about 11 makes the treatment method more cost-effective. On the other hand, the more the alkaline water wash solution is used, the less effective it is in repairing and removing pollutants from the gas, which is reflected in the reduction of the pH value, and the alkaline water wash may need to be updated or replaced regularly with some new treatment solution to maintain its effectiveness in repairing and removing pollutants from the gas. For example, the inventors have determined through testing that when the pH of the water wash drops below 10, such as when the pH of the alkaline water wash drops to about 9.5, the alkaline water wash becomes increasingly less effective at remediating contaminants in the gas and / or precipitating them from the gas / water wash, some H2S and CO2 will begin to pass through, and when the pH drops below 9, the ability of the alkaline water wash to remediate and remove contaminants from the gas is significantly reduced from its initial ability at pH 10 or higher, and at a pH of about 8, the ability of the alkaline water wash to further remediate and remove contaminants from the gas is essentially exhausted, even if the various precipitates released from the treated gas and water wash are continuously or somewhat continuously removed. Therefore, if the alkaline water wash solution is renewed or replaced when its pH drops below 10, the alkaline water wash solution may be most effective in removing and / or remediating contaminants from the contaminated gas, and may be close to 100% effective, but this may not be the most practical and cost-effective method of removing contaminants using the water wash solution because when the pH drops below 10, there are still a large number of reactants in the alkaline water wash solution. The present inventors have discovered that a practical, cost-effective method of using an alkaline aqueous wash solution is to first raise the pH to about 11 by adding an alkaline substance (e.g., one or more hydroxides), use this solution to remove contaminants from the contaminated gas stream until the pH of the solution drops below 10 or even to 9-8, and then refresh or replace the solution with fresh solution having a pH of about 11, repeating these steps as often as necessary.

[0020] A second discovery of the present inventors is that, in order to control or limit the amount of solids generated or released into the water wash, the water wash solution can be further modified by adding an appropriate amount of organic acids (e.g., fulvic acid and humic acid) as the water wash is used to remediate the contaminated gases being bubbled or otherwise passed, so that little or no such solids are precipitated from the water wash solution, even when the pH of the water wash solution is 10 and above. The organic acid can be added to the water wash solution, for example, at a dosage rate in the range of 0.005 wt % to 3.0 wt % to achieve a pH of about 11 from the normal initial pH of about 7 for the water. Without limiting the present invention, the present inventors believe that organic acids (e.g., fulvic acid and humic acid) are effective because they bind to the contaminants being remediated and keep them dissolved and / or suspended in the water wash solution, thereby minimizing the formation of any solids that precipitate from the water wash solution as the contaminated gases are bubbled or otherwise passed through the water wash solution. Although some solids may be generated in and / or released into the wash solution, the amount of these solids is limited so that they are largely retained in the wash solution and do not form solid precipitates released from the wash solution and therefore do not accumulate in the treatment system where the treatment method is carried out and do not cause problems such as partial and complete blockage of pipelines that must be resolved.

[0021] Furthermore, the inventors have determined that a process for treating contaminated gas comprising a water wash solution having an elevated pH and an appropriate amount of organic acids (e.g., fulvic acid and humic acid) can be operated on a continuous or substantially continuous basis provided that when the pH of the water wash solution drops below about 10, the water wash solution is periodically renewed by withdrawing an amount or portion of the water wash solution that has been used to treat some of the contaminated gas and will have a correspondingly reduced pH and may have an amount of suspended solids therein, and replacing the withdrawn solution with an equal amount of fresh water wash solution having a pH of about 11. Controlling or limiting the amount of solids generated in or released into the water wash by adding one or more of these organic acids and periodically renewing the water wash solution, and thereby preventing the release of precipitates from the water wash solution, makes it possible to continue to remediate the contaminated gas using the water wash solution in the process according to the invention (for as long as necessary, which may be substantially indefinitely), making the process even more cost-effective and efficient. For treating contaminated natural gas from one or more wells that are connected together, it is highly desirable to be able to operate the process on a continuous basis, as wells are typically operated continuously.

[0022] Generally, all hydroxides can be used, provided that they are soluble or dispersed in the washing solution. However, some hydroxides have lower costs, such as NaOH and KOH, and if used, can make it more economically advantageous to use the composition and treatment process of the novel washing according to the present invention. In addition, if the novel washing according to the present invention will be used together with a polluted gas (such as natural gas) comprising a large amount of NaCl salts, the NaCl salts will usually be dissolved in any water contained in the polluted gas, then it may be necessary to use a hydroxide other than NaOH in the washing solution. This will improve the efficiency of the treatment process, because this washing solution will be able to absorb more NaCl from the polluted gas before the solution becomes NaCl saturated, and can help prevent any salt from precipitating out from the washing solution.

[0023] The washing solution according to the present invention may also include a certain amount of other compounds in addition to increasing alkaline hydroxides, organic acids (such as fulvic acid and humic acid) that prevent the release of precipitates, and antimicrobial agents. This may depend on the specific characteristics of the polluted gas to be treated and the desired results. For example, the new washing solution may include 0.5 volume % to 20 volume % of one or more organic liquids (such as alcohol, hexane, toluene, xylene, etc.), whose vapor pressure is higher than the vapor pressure of water. These organic liquids help to increase the vapor pressure of the washing solution, so that a certain amount of hydroxide in the washing solution will be present in the vapor of the organic liquid, and the organic liquid is retained in the gas that has been repaired after the novel washing according to the present invention, for example, in the head space above the washing solution in the reaction chamber where the washing solution is placed, and thus the hydroxide can continue to react with any residual H2S and / or other pollutants remaining in the repaired gas and repair.

[0024] The third discovery of the inventors is a new treatment method and system for treating contaminated gas (including natural gas from a well as described herein), which is a hybrid between the improved water wash method and the continuous treatment method according to the first discovery above, wherein the contaminated gas is contacted with a treatment composition having a very high concentration of hydroxide (the hydroxide comes from one or more hydroxides), such as the treatment compositions disclosed in PCT / US2018 / 050913 and PCT / US2018 / 064015 and the '911 and '064 patents and variations thereof, rather than being contacted with the improved water wash method according to the first discovery.

[0025] The new treatment method according to the third discovery can be used to treat contaminated gases, comprising the following steps: allowing a contaminated gas flow to flow through a pipeline; treating the flowing flow of the contaminated gas by injecting droplets of a liquid treatment composition containing a total of 35-55 weight % of one or more hydroxides into the contaminated gas flow flowing in the pipeline, so that the liquid treatment composition is mixed into the contaminated gas in the flowing flow and repairs the pollutants in the contaminated gas; downstream of the injection of the liquid treatment composition into the pipeline, water is injected into the mixed flowing flow of the contaminated gas flow and the liquid treatment composition in the pipeline; and then separating the treated contaminated gas flow from any residual amounts of the liquid treatment composition, water and precipitate in a separator.

[0026] The treatment process may be operated on a continuous basis, with the amount of liquid treatment composition injected into the flowing stream of contaminated gas in the pipeline being based on the amount of contaminated gas to be treated and the type and amount of contaminants in the contaminated gas. Any volume of contaminated gas may be treated, but for natural gas from one or more wells that are typically collected together at a given location, a typical daily production of contaminated natural gas may be 500,000 ft 3 Up to 5,000,000ft 3 , and the pollutants may include different amounts of salts, CO2, H2S, SO2, other sulfur-based pollutants (including mercaptans and thiophenes), and metals. Technically, water may also be considered a pollutant in the gas, but in the present disclosure, water is not considered to be one of the pollutants to be repaired. In order to treat this volume of contaminated natural gas, the inventors have determined that the appropriate amount of treatment composition (such as those disclosed in PCT / US2018 / 050913 and PCT / US2018 / 064015 and the '911 and '064 patents and their variations) is in the range of 1 US gallon / hour to 150 US gallons / hour. This amount of treatment composition is also suitable for other contaminated gases of similar volume. The amount of water injected downstream of the pipeline into which the treatment composition is injected can be the same or substantially the same as the amount of the treatment composition injected, but if any precipitates and solids released from the contaminated gas in the treatment step need to be flushed into the separator, the amount of water injected can be significantly larger. There is usually no harm in using excess water because the cost is relatively small. It is important that the precipitates and solids released during the treatment step do not accumulate in the pipeline. By monitoring the pH, pKa and / or other characteristics of the treated contaminated gas and / or liquid in the separator, the most appropriate amount of treatment composition can be determined, and appropriate adjustments can be made to the treatment system and / or method based on the monitored characteristics. Such adjustments can include: adjusting the amount of treatment composition injected in the treatment step; adjusting the amount of water injected; adjusting the pipeline location where the treatment composition and / or water is injected; adjusting the distance between the location where the treatment composition and water are injected, etc.

[0027] The distance between the location where the treatment composition is injected in the treatment step and the location where the water is injected into the pipeline can be based on the flow rate of the polluted gas in the pipeline, because the inventors have determined that for efficiency purposes, the polluted gas should be in contact with the treatment composition for at least 0.2 seconds, preferably at least 0.5 seconds, before the water is injected. The inventors have determined that this contact amount is sufficient to allow the treatment composition to fully repair a large amount of pollutants in the polluted gas, such as 40-80wt% of the pollutants, while substantially exhausting most of the reactivity of the treatment composition. Therefore, if the polluted gas flows at a rate of 3-10ft / second, the distance between the treatment composition and the location where the water is injected into the pipeline can be 0.6-3.0 feet. Once the water is injected into the pipeline downstream of the treatment composition injection point, the water will dilute any residual amount of the treatment composition, so that the treatment composition can continue to repair the residual pollutants, but not too quickly and effectively. Once the polluted gas is treated with the treatment composition, precipitates and solids may be released from the polluted gas, and the injected water provides an important function of preventing or minimizing any accumulation of precipitates and solids, which is important for the effective and continuous operation of the treatment system and treatment method. The precipitates and solids may include salts, carbonate crystals, sulfur, sulfur-containing compounds, metals, etc., and the precipitates will generally flow into a separator with the injected water and liquid treatment composition, where the treated polluted gas is separated from these liquids and precipitates. The distance between the location of the water injection pipeline and the separator may vary, and it is generally desirable to quickly separate the treated polluted gas from the liquid and precipitates after the water is injected, so the distance between the pipeline location and the water injection location and the separator location may be, for example, as small as 1 to 25 feet. If desired, the separated liquid and precipitate may be disposed of or collected and further processed.

[0028] This new treatment method may further include: a second treatment step, in which an additional amount of the treatment composition is injected into the treated polluted gas flow stream in the pipeline after the separation step; and a second separation step, in which the treated polluted gas flow stream is separated from any residual amount of liquid treatment composition and any further precipitates released from the treated polluted gas in a second separator. The amount of treatment composition added in the second treatment step can be significantly less than the amount of treatment composition added in the first treatment step, for example, for the same amount of gas, ≤ 1 / 5 of the amount in the first treatment step, because most of the pollutants have been repaired / removed from the polluted gas in the first treatment step. The treatment method may also include a second water injection step, in which an additional amount of the treatment composition is injected downstream of the pipeline in the second treatment step, and water is injected into the treated polluted gas in the pipeline. However, because as a result of the second treatment step, much less precipitates will be released from the twice treated polluted gas, a second water injection step may not be required to prevent precipitates from accumulating in the pipeline. Therefore, the second water injection step is optional and can be omitted.

[0029] The processing systems and methods according to the third discovery are advantageous over conventionally known processing systems and methods for processing contaminated gases. Using this new method, the inventors have been able to successfully process highly contaminated gases (including natural gas) in a practical, cost-effective manner in a continuous processing process, which all conventionally known processing systems and methods have failed to achieve. For example, the inventors have been able to process large quantities of highly contaminated natural gas (e.g., 500,000 ft per day) 3 Up to 5,000,000ft 3 The new treatment systems and methods have been run by several companies and have achieved 40% to almost 100% remediation of contaminants in an efficient and cost-effective manner. In contrast, this same highly contaminated natural gas could not be treated in a practical and cost-effective manner using conventional known treatment systems and methods. Owners of wells that output highly contaminated natural gas are essentially forced to shut down these wells because they cannot treat the highly contaminated natural gas in a practical and cost-effective manner, and thus the owners cannot extract the crude oil that would be output from the same wells along with the highly contaminated natural gas. The new treatment systems and methods allow these shut-in wells to operate.

[0030] In addition, the treatment system and method according to the third discovery are very flexible in the extent to which pollutants in highly polluted gases (including natural gas) are repaired using the new system and method. For example, in the treatment of highly polluted natural gas, the inventors are able to adjust the system and method to achieve different degrees of repair, which is desirable in any given situation. For polluted natural gas, it is usually sufficient to reduce the level of pollutants, especially H2S by 40-80 weight % or volume % to make the polluted gas accepted by the refinery, and the refinery will further repair the pollutants as needed or desired. Although this partially repaired natural gas may still be considered to have a high sulfur content, it can be extracted from the well and sold for direct use or further refining, and being able to extract natural gas also allows crude oil to be extracted from the well. In addition, if the first processing step and the first separation step and the second processing step and the second separation step are used, about 100% of the repair of pollutants in highly polluted natural gas can be achieved. Therefore, the repair level achieved by the treatment system and method can be easily adjusted according to the needs and expectations of consumers.

[0031] Public Intentions

[0032] Although the following publicly released disclosure is described in detail in order to ensure a full and helpful understanding of the invention, this is not intended to hinder the purpose of the patent, which is to cover every new inventive concept therein, no matter how it may be later concealed by changes in form or the addition of further improvements. The claims at the end of this specification are the main auxiliary means to achieve this purpose, because it is these claims that meet the requirements of pointing out improvements, combinations and methods of the inventive concept. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is a schematic diagram of a water-washing type reaction chamber according to an exemplary embodiment of the present invention, which can be used in a treatment method for remediating pollutants in polluted gas.

[0034] Figure 2 According to the present invention, Figure 1 A flow chart of an exemplary embodiment of a batch process method for remediating a contaminated gas in a process chamber.

[0035] Figure 3 According to the present invention, Figure 1 A flow chart of an exemplary embodiment of a continuous process method for remediating a contaminated gas in a process reaction chamber.

[0036] Figure 4 is a schematic diagram of a processing system for remediating contaminated gas according to another exemplary embodiment of the present invention.

[0037] Figure 5 According to the present invention, Figure 3 A flow chart of an exemplary embodiment of a process for remediating a contaminated gas using a processing system. DETAILED DESCRIPTION

[0038] A first aspect and embodiment of the present invention relates to a novel treatment system and method for effectively and cost-effectively removing nearly all of the contaminants typically present in a contaminated gas. The contaminated gas may be natural gas from a well, combustion gas from a fossil fuel, methane gas from a landfill, etc. The contaminated gas may contain large amounts of salts, CO2, H2S, other sulfur-based contaminants (including mercaptans and thiophenes), metals, SO2, NH3, etc., regardless of how many contaminants are present in the gas. This treatment method is based on the inventors' discovery that if the water wash is modified to an alkalinity of pH above 8, preferably above 8 to about 11, by the addition of one or more alkaline materials (including hydroxides), when the gas is bubbled or otherwise passed through the alkaline water wash with a contact time of 0.2-5.0 seconds, preferably at least 1.0 seconds, this alkaline water wash is a surprising, extremely effective treatment composition for removing most, essentially all, of the contaminants from the contaminated gas. Based on extensive experiments, the inventors have identified this treatment method using alkaline water washing according to an exemplary embodiment and found that it is surprisingly extremely effective in removing most salts, CO2, H2S, other sulfur-based pollutants (including mercaptans and thiophenes), SO2, NH3 and metals from contaminated gases, and if the alkaline water washing solution is replaced or re-strengthened regularly to maintain its effectiveness / effectiveness, it can be effectively used to remove most pollutants from various contaminated gas streams (including highly contaminated gas streams) in a practical, cost-effective manner.

[0039] Various alkaline substances can be added to the water wash to increase its pH to a target value of about 11. These alkaline substances include one or more hydroxides. Essentially any hydroxide can be used, but some suitable hydroxides include potassium hydroxide (KOH), sodium hydroxide (NaOH), ammonium hydroxide (NH4OH), lithium hydroxide (LiOH), magnesium hydroxide (Mg(OH)2) and manganese hydroxide (Mn(OH)2, Mn(OH)4), etc., all of which are readily soluble in water. The water wash solution may contain a total of about 15-25% by weight of one or more hydroxides for raising the pH of the solution from the pH of water (usually about 7) to about 11, but the specific amount or weight % of the hydroxide required to achieve this will depend on the specific hydroxide used and the desired result. Thus, for example, if KOH is added to the water wash to increase the pH of the water from about 7 to about 11, the inventors have found that this can be achieved by mixing a certain amount of concentrated (45% by weight) KOH aqueous solution with a certain amount of water in a ratio of about 1:1 to 1:2, or by adding an appropriate amount of KOH powder or KOH hydrate flakes to the water. NaOH can also be used as a hydroxide in water washing, but it may not be the most effective hydroxide if the polluted gas to be treated contains a large amount of salt. Considering that Na is also the main component of the common salt NaCl, using NaOH as one of the hydroxides in the water washing solution will reduce the amount of salt absorbed by the water washing solution from the polluted gas before the water washing solution becomes saturated with salt. Once the water washing solution is saturated with salt, any more amount of salt absorbed by the water washing solution may be released from the water washing solution as a solid. The cost of NaOH is lower than other hydroxides, and it can be a suitable hydroxide for many applications of the system and method according to an exemplary embodiment of the present invention. NH4OH is a suitable hydroxide for increasing the pH value of water washing, but it may not be the only compound for this purpose, because it may release ammonia (NH3) into the gas to be treated, and the government has restrictions on the amount of NH3 contained in the gas, such as natural gas should not contain more than 14ppm of NH3. Therefore, for example, an appropriate amount of other hydroxides such as KOH, NaOH or LiOH can be used together with NH4OH to increase the pH value of water washing. As the gas is bubbled through the solution, the NH4OH not only works effectively in the alkaline water scrubber solution, but also advantageously increases the vapor pressure of the alkaline water scrubber so that some hydroxide exists as vapor in the head space above the water scrubber solution, and any contaminants remaining in the treated gas after it passes through the water scrubber can be further remediated by the hydroxide vapor in the head space above the water scrubber in the reactor.

[0040] In addition to hydroxides, other substances that may be added to the water wash to improve its effectiveness and / or stability in removing contaminants from the gas include smaller amounts (e.g., less than 1% by volume) of surfactants (e.g., sodium dodecyl sulfate or commercially available anionic polymers), buffers (e.g., phosphoric acid (H3PO4)), antimicrobial compounds (e.g., potassium silicate (K2SiO3), copper sulfate (CuSO4), chlorine, etc.).

[0041] Water is generally effective for removing salts from contaminated gases because salts are readily soluble in water and are easily transferred from the gas into the water when the gas is contacted with the water in a water wash. However, the inventors have discovered that if the water for the water wash is made alkaline to a pH greater than 8 by the addition of an alkaline substance (e.g., a hydroxide), then the water wash becomes surprisingly more effective in removing substantially all of the salts from the gas, and also becomes very effective in removing significant amounts of H2S and other sulfur-based contaminants, CO2, and metals from the gas. For example, the present inventors have found that if the pH of the water wash is raised to a level of about 11 by adding an alkaline substance (e.g., hydroxide), and a gas highly contaminated with H2S, CO2, SO2, salts, etc. is passed through the alkaline water wash (suitable contact time is in the range of 0.2-5 seconds, preferably at least 1.0 second), then: 1) substantially all of the salts enter the water wash from the gas and / or precipitate out of the water wash; 2) many of the sulfur-based contaminants in the gas (including H2S, SO2, mercaptans, and thiophenes) are precipitated by contact with the alkaline substance (e.g., hydroxide) added to the water wash. 1) The gas is treated by reacting with an alkaline substance (e.g., hydroxide) added to the water wash and then precipitated from the gas / alkaline water wash, for example as carbonate crystals; and 2) The gas is treated by reacting with an alkaline substance (e.g., hydroxide) added to the water wash and then precipitated from the gas / alkaline water wash, for example as metal sulfides. It is desirable to remove salts from the contaminated gas because salts are more likely to be released from the gas as it is transported along a pipeline or other component of the processing system and may cause severe blockage of the pipeline and other system components. If the gas has a respective content of 30,000 ppm or more of H2S, SO2, and CO2 before the water wash, these respective contents can be reduced, for example, to about 10,000 ppm or less after passing through the alkaline water wash. Note that pollutants including H2S, SO2, and CO2 may be present in the polluted gas at 60,000 ppm, 100,000 ppm, and several hundred ppm.

[0042] Salts are removed from the gas as it passes through an alkaline water wash, because salts are very soluble in the alkaline water wash and they will usually precipitate from the water wash in the form of salt crystals once the water wash is saturated with salts, and are likely to precipitate from the modified water wash solution having an increased pH according to the invention, particularly when the pH is increased to above 10, and if no other components are added to the water to prevent or limit the formation and release of precipitates.

[0043] According to the present invention, it is desirable to use drinking water in the wash solution. Drinking water may contain some bactericides, such as chlorine, but contains little or no salt therein, so before the wash solution becomes saturated with salt, the water may be able to accept as much salt as possible. However, if drinking water is not available at any given location where it is necessary to use the novel wash solution and treatment method according to the present invention to treat polluted gas, it is appropriate to use available water (such as surface water) from other local sources that are not itself significantly polluted. No matter what kind of water is used, it may be necessary to add some types of antimicrobial agents to the water. For example, some chlorine sources except NaCl may be added, or another antimicrobial agent such as copper sulfate (CuSO4) may be added in an appropriate dosage. Chlorine and copper sulfate are commonly used as antimicrobial agents in drinking water, and may be added in similar dosages as in drinking water.

[0044] In addition to the removal of salts, there are reactions between the hydroxides in the alkaline water wash and various contaminants in the gas that result in other contaminants being remediated and / or removed as the gas passes through the water wash, including reactions with H2S, CO2, metals including Fe, Al, Cr, V, etc. Under the low redox conditions of the natural gas formation and the pH range of 8-11 for the alkaline water wash, metal hydroxides and metal sulfides are favored and will precipitate out until or unless a significant amount of carbonate is absorbed from any CO2 in the contaminated gas, after which the metal carbonate can precipitate out. If KOH is used to increase the pH of the water wash, the KOH will react with the H2S and remediate it to form potassium sulfide (K2S) according to the following equation:

[0045] KOH+H2S→K2S+H2O.......(1)

[0046] Unlike metal sulfides, K2S is highly soluble in water. If metals (e.g., Fe, Al, V, etc.) are present in the polluted gas, metal sulfides including these metals will also precipitate from the alkaline water wash. The speciation and solubility of the metals are a function of pH, redox potential, carbonate content, and metal and salt concentrations. CO2 can be removed from the polluted gas by contact with the alkaline water wash according to the following reaction to form bicarbonate crystals:

[0047] CO2 + OH– → HCO3 – ....... (2),

[0048] K + + HCO3 – → KHCO3 ....... (3).

[0049] In a test experiment of the treatment method according to an exemplary embodiment of the present invention, when salt is collected in the alkaline water wash and becomes saline, the saline water absorbs CO2 and potassium bicarbonate (KHCO3) crystallizes out of the solution. If other hydroxides besides KOH are used in the alkaline water wash, a similar reaction will occur.

[0050] Although according to an exemplary embodiment of the present invention, the ideal upper limit of the pH value of alkaline water washing is about 11, in fact, by adding a larger amount of alkaline substances (such as hydroxides), the pH value of water washing can be increased to more than 11, and according to the treatment method of the present invention, this alkaline water washing solution is also very effective in removing most of the pollutants from the polluted gas. However, as a practical problem in terms of cost, compared with increasing the pH of water from about 7 to 11, increasing the water washing pH to more than 11 requires proportionally much more of this alkaline substance, so the upper limit of about 11 is optimal for cost efficiency. On the other hand, the more alkaline water washing solution is used, the worse the effect of its repair and removal of pollutants from the gas, which is reflected in the pH and pKa of water washing. Therefore, alkaline water washing may need to be regularly replaced or updated to maintain its effect of repairing and removing pollutants from the gas. For example, the inventors have determined through extensive testing that when the pH of the water wash drops below 10 (e.g., when the pH of the alkaline water wash drops to about 9.5), the alkaline water wash becomes increasingly less effective at remediating contaminants in the gas and / or precipitating them from the gas / water wash, and some H2S and CO2 will remain in the treated gas. When the pH drops below 9, the ability of the alkaline water wash to remediate and remove contaminants from the gas is significantly less than its initial ability at pH 10 or higher, and at pH about 8, the ability of the alkaline water wash to further remediate and remove contaminants from the gas is substantially exhausted or depleted, even though the various precipitates released from the treated gas and water wash are continuously or somewhat continuously removed from the water wash. Therefore, if the water wash solution is replaced each time the pH of the water wash solution drops below 10, the alkaline water wash solution can most effectively remove contaminants from the contaminated gas, possibly approaching 100% effectiveness. However, this may not be the most practical, cost-effective method of removing contaminants using a water wash solution, and cost is very important for practicality.

[0051] The inventors have found that a practical, cost-effective method of treating polluted gas with an alkaline water wash solution so that most of the pollutants in the gas are removed from the gas and precipitated from the water wash solution is to first raise the pH to about 11 by adding an alkaline substance (e.g., hydroxide), and then this solution can be used to remove pollutants from the polluted gas stream until the pH of the solution drops to between 9 and 8, and then the solution is replaced with a fresh solution having a pH of about 11, while repeating these steps as often as necessary. When the precipitate is released from the water wash solution and precipitates at the bottom of the reaction chamber where the water wash solution is placed, the precipitate can be removed from the reaction chamber together with a certain amount of spent water wash solution and disposed of, or further processed if any precipitate has commercial value. The spent water wash solution generally contains little or no H2S, even if the treated polluted gas contains a large amount of H2S, but may contain various amounts of solids that are soluble in the spent water wash solution. This spent water wash solution can be safely disposed of, for example, by pumping it back underground through a well.

[0052] The wash solution of the exemplary embodiment discussed in accordance with the present invention can be modified by adding an appropriate amount of organic acid (e.g., fulvic acid and humic acid) for the purpose of controlling or limiting the amount of solids produced or released into the wash when the wash is used to remediate contaminated gases that are bubbled or otherwise passed therethrough, even when the pH of the wash solution is 10 and above. This helps prevent solids from accumulating and piling up in the treatment system (including pipelines) and minimizes downtime for removing solids from the system. In addition, the inventors have determined that a method for treating contaminated gases involving a wash solution having an elevated pH and an appropriate amount of organic acid (e.g., fulvic acid and humic acid) can be operated on a continuous or substantially continuous basis, provided that the wash solution is regularly renewed and / or replaced when the pH of the wash solution drops from an initial value of about 11 to a value less than about 10. Such renewal of the wash solution may comprise withdrawing an amount or part of a wash solution which has been used to treat some polluted gas and which will accordingly have a reduced pH and possibly a certain amount of suspended solids therein, and replacing the withdrawn solution with an equal amount of fresh wash solution having a pH of about 11 and an appropriate amount of organic acid (e.g. fulvic acid and humic acid).

[0053] Organic acid, such as fulvic acid and humic acid, can be added to the washing solution at a dosage rate of, for example, 0.005% by weight to 3.0% by weight. Without limiting the present invention, the inventor believes that organic acid (such as fulvic acid and humic acid) is effective because they are combined with the pollutants to be repaired, and they are kept in the washing solution, thereby minimizing the formation of any solids precipitated from the washing solution when the polluted gas is bubbled or passes through the washing solution. Although some precipitates and solids may be produced and / or released in the washing solution, fulvic acid and humic acid help to limit the amount of precipitates and solids released from the washing solution. Therefore, in the treatment system, the treatment method carried out using the washing solution containing organic acid (such as fulvic acid and humic acid), precipitate and other solids are unlikely to accumulate in the treatment system. The accumulation of solids can cause problems, such as partial and complete blocking of pipelines, etc., which must be solved by, for example, shutting down the system and removing the precipitate accumulated. By adding one or more of these organic acids to control or limit the amount of solids produced in the water wash or released into the water wash solution, it becomes easier to continue to remediate the contaminated gas using the water wash solution in the treatment system and method according to the present invention (for as long as necessary), which makes the treatment system and method even more cost-effective and efficient.

[0054] As one way to control the treatment process in a continuous manner, the inventors have determined that if the pH of the fresh wash solution is initially 11, which is an effective starting pH as described herein, the pH can be monitored and whenever the pH drops below 10, at which point the wash solution may contain some suspended solids and be turbid, a certain amount of the spent wash solution can be removed from the reactor containing the wash solution and replaced with an equal amount of fresh wash solution having a pH of about 11 and containing an appropriate amount of an organic acid (e.g., fulvic acid and humic acid as described herein). For example, the inventors have determined that by removing about 1 / 20 to 1 / 8 of the wash solution from the reactor (e.g., at the bottom of the reactor) and replacing it with an equal amount of fresh wash solution (e.g., introduced at the top or middle of the reactor), little or no precipitate will accumulate in the reactor or related parts of the treatment system. Thus, problems due to clogging of the system are not encountered, and the treatment process can be run continuously for long periods of time, such as weeks or months.

[0055] The washing solution according to an exemplary embodiment of the present invention may also contain a certain amount of other compounds, depending on the specific characteristics of the polluted gas to be treated and the desired results. For example, a fresh washing solution may include 0.5 volume % to 10 volume % of one or more organic liquids (e.g., alcohol, hexane, toluene, xylene, etc.), the vapor pressure of the organic liquid being higher than the vapor pressure of water. Somewhat similar to the use of ammonium hydroxide as one of the hydroxides, these organic liquids help to increase the vapor pressure of the washing solution, so that some amount of hydroxide in the washing solution will be present in the vapor of the organic liquid, and the organic liquid is retained in the gas that has been repaired after the novel washing according to the present invention, for example, in the head space above the washing solution in the reaction chamber where the washing solution is placed, so that the hydroxide in the treatment composition can continue to react with any residual H2S and / or other pollutants remaining in the repaired gas and repair it.

[0056] refer to Figure 1, depicts a schematic diagram of a reactor or bubbling column 100 that can be used in a treatment method according to an exemplary embodiment of the present invention for removing and / or remediating most contaminants from a contaminated gas. The bubbling column 100 has a reaction chamber therein that can be partially filled with a certain amount of an alkaline aqueous scrubbing solution 102 having a pH value of about 11, while the upper portion of the reaction chamber defines a head space 104 above the solution 102. When the contaminated gas 105 is bubbled or otherwise passed through the alkaline aqueous scrubbing solution, many of the contaminants therein will be removed and / or remediated, as described above, and the treated gas can then pass through a baffle 108 or the like (which can be disposed in the head space 104) to help remove some of the alkaline aqueous scrubbing solution that may remain in the gas, and finally the treated gas is discharged from the upper portion 110 of the reaction chamber. The premixed aqueous scrubbing solution 102 can be introduced directly into the reaction chamber, or separate components of the aqueous scrubbing solution, such as water and hydroxide, can be introduced into the reaction chamber through inlets 112, 114 to form an alkaline aqueous scrubbing solution. Liquid level sensor 115 can be used to set and control the amount of solution 102 in the reaction chamber, and sensor 116 can be used to monitor the pH and / or other characteristics of solution 102. Based on Stokes Law of bubble formation and bubble rise, the polluted gas 105 can be controlled to flow into the bottom of the reaction chamber, passing through the water washing solution 102 with the required liquid contact time, such as 0.2 to 5.0 seconds, preferably at least 1.0 seconds. This can include a discharge nozzle 106 in which many small discharge ports are defined, and can also include a device (not shown) for interrupting the gas flow through the reaction chamber, so that the gas cannot flow through the water washing solution uninterruptedly in the form of a stream or large bubbles, and therefore will have a larger surface area for reacting with the treatment composition. Such an interruption device can include filling the reaction chamber or part thereof with a fine non-reactive medium (not shown) (e.g., stainless steel wool, fine gravel, porous plates, etc.), and when the polluted gas flows through the water washing solution, it will pass through these media. The treatment system can be automated using a controller 120, which is, for example, a programmed ECU with an associated memory, which stores programs, predetermined thresholds, etc., sensed characteristics, etc. The controller may receive inputs from sensors 115, 116 and may control the flow of solutions and gases into and out of the reaction chamber by opening and closing various solenoid valves (not shown) associated with the various inlets and outlets of the reaction chamber.

[0057] The size of the reactor 100 may depend on the amount of contaminated gas to be treated and / or the amount of contaminants contained in the gas to be remediated and removed by the alkaline water wash solution. For example, if a large continuous volume of contaminated gas is to be treated in the reactor chamber, such as from a well at a rate of 500,000 ft 3 / day up to 15,000,000ft 3 / day, the reactor may be four (4) feet in diameter, twenty (20) feet high, and have a volume of 1880 U.S. gallons, of which solution 102 may fill about 3 / 4 of the volume or about 1410 gallons. As another example, if the continuous flow rate of natural gas from the well is less than three (3) million ft 3 / day, then a 1000 U.S. gallon or smaller reactor may be used.

[0058] The processing system may be automated using a controller 120 (e.g., a programmed ECU with associated memory storing programs, predetermined thresholds, etc., sensed parameters, etc.). The controller may receive inputs from sensors 115, 116 and control the flow of solutions and gases into and out of the reaction chamber by opening and closing various solenoid valves (not shown) associated with the respective inlets 105, 112, 114 and outlets 110, 118 of the reactor 100. The wastewater wash solution and precipitate discharged through the discharge outlet 118 may be discarded in an appropriate manner, or some of the precipitate may be recovered, processed, and sold, depending on the economics of the situation.

[0059] The treatment method involving the water wash solution according to the present invention can be operated in batch or continuous mode. In addition, the treatment method can be controlled to release precipitates from the water wash solution or limit the release of precipitates. Whether the precipitate and solids are released from the solution depends largely on the specific formulation of the water wash solution used in the bubble column reactor, for example, the pH value of the water wash solution, and whether the water wash solution contains a certain amount of one or more organic acids, such as fulvic acid and humic acid. If the water wash solution does not contain organic acids, many pollutants in the treated polluted gas will be removed and precipitated from the water wash solution; and if the water wash solution contains organic acids, some pollutants in the treated polluted gas will be repaired and remain dissolved or suspended in the water wash solution. For any formulation of the water wash solution, the treatment method using the water wash solution according to the present invention can be operated on a continuous or semi-continuous basis, which is most effective and practical for treating a continuous flow stream of polluted gas (such as natural gas extracted from the ground through a well or a group of wells). The production of contaminated natural gas from the well is typically 500,000ft 3 / day to 15 million ft 3 / sky.

[0060] use Figure 1 An exemplary embodiment of a batch process for removing pollutants from a polluted gas by a treatment system is shown in FIG. Figure 2As shown. In step S1, the reactor 100 is partially filled with a water washing solution 102 having an initial pH of about 11. An appropriate amount of premixed water washing solution or components of the water washing solution (including water and hydroxide) can be introduced into the reaction chamber through inlets 112, 114 to partially fill the reaction chamber. A liquid level sensor 115 can be used to set and control the liquid level of the solution 102 in the reaction chamber, and a sensor 116 can be used to monitor the pH, pKa and / or other characteristics of the solution 102. In step S2, a polluted gas stream 105 is introduced into the reaction chamber through a nozzle 106. As the polluted gas passes upward through the alkaline water washing solution, many of the pollutants therein will be repaired or removed, for example, some pollutants, including salts, will be released from the gas and the water washing solution and settle to the bottom of the reaction chamber, and some of the repaired pollutants will remain dissolved and / or suspended in the water washing solution, especially if the solution contains one or more organic acids, such as the above-mentioned fulvic acid and humic acid. After the contaminated gas has been treated by the water wash solution 102, the treated gas may pass through a baffle 108 or the like (which may be disposed in the head space 104) to help remove some of the alkaline water wash solution remaining in the gas, and then the treated gas may be exhausted from the upper portion 110 of the reaction chamber. The treated gas needs to contain as little water as possible.

[0061] As the contaminated gas stream passes through the alkaline water wash solution in the reaction chamber, the hydroxides and / or other alkaline chemicals in the solution will react with the contaminants in the gas, and the pH and pKa of the solution will gradually decrease, so these characteristics can be monitored as an indication of the residual strength of the solution 102. In step S3, it is determined whether the pH of the solution is less than 9.0, when the pH is less than 9.0, the solution 102 is considered to be mostly exhausted. If so, in step S4, the spent solution can be removed from the reaction chamber, for example, through a waste discharge outlet 118 at the bottom of the reaction chamber. Any precipitates and other solids that have been released from the treated contaminated gas into the solution 102 will tend to accumulate at the bottom of the reaction chamber and can be removed with the spent solution 102. The method can then return to step S1, and another volume of alkaline water wash solution can then be introduced into the reaction chamber, and the treatment method can be continued by repeating these steps as long as necessary.

[0062] Figure 3 Shows the use of Figure 1 The treatment system shown is an exemplary embodiment of a continuous treatment method for removing pollutants from polluted gas. In this method, when the pH value of the water washing solution 102 drops to a predetermined value, such as below 10 or below 9, the water washing solution 102 can be periodically renewed instead of being Figure 2 In this continuous process, the treatment solution needs to include an organic acid (e.g., fulvic acid and / or humic acid) in an amount as described herein to help limit the amount of precipitate and solids released from the treatment solution.

[0063] refer to Figure 3 In step S11, the reactor 100 is partially filled with a water wash solution 102 having an initial pH value of about 11; in step S12, a contaminated gas stream 105 is introduced into the reactor through a nozzle 106. Similarly, the pH and / or pKa can be monitored using a sensor 116, and as the treatment method continues and the pH and pKa of the water wash solution 102 decrease, the water wash solution can be periodically renewed to keep the solution in appropriate conditions to effectively remediate the contaminated gas. For such renewal, the inventors have determined that when the pH drops below 10, this will be an appropriate time when the water wash solution should be renewed, especially if the contaminated gas to be remediated contains an amount of H2S exceeding 5 ppm, that is, the used water wash solution may not have been technically exhausted at this time. The H2S content of natural gas directly from the ground may contain very high concentrations of H2S, such as an amount of ≥60,000 ppm, and the treatment method according to an embodiment of the present invention is effective for remediating such high levels of H2S. The pH value of the water wash solution must be above 9.95 so that the solution reacts with the H2S in the contaminated gas and remediates. Therefore, in step S3 of the method, a sensor 116 is used to determine every few milliseconds or so whether the pH value of the solution is less than 10.0. If so, the washing solution can be updated in step S4, a portion (e.g., 1 / 20 to 1 / 8) of the reacted washing solution in the reaction chamber is removed through the discharge outlet 118, and an equal amount of fresh washing solution with a pH of about 11 is introduced into the reaction chamber through the inlets 112 and 114. The used solution removed may contain a certain amount of solid matter dissolved and / or suspended therein, which may appear turbid accordingly, and can be removed through the waste discharge outlet 118 at the bottom of the reaction chamber. If the answer at S3 is negative, that is, the pH is not less than 10.0, then the method returns to step S2 and continues the method. The treatment method can be continued by repeating these steps as long as necessary.

[0064] The present inventors conducted a beta test of the treatment method according to the present invention, using a water wash solution having an elevated pH and one or more organic acids (e.g., fulvic acid and humic acid) in the amounts described above, for remediation of contaminated natural gas from the ground. In the beta test, the flow rate of the contaminated natural gas was approximately three (3) million ft 3 / day or 125,000ft 3 / hour. However, it should be recognized that the natural gas flow from a given well is not generally at a steady or constant flow rate, but will generally vary within any 24-hour period, and the flow rate of the natural gas being treated in the treatment method according to an exemplary embodiment of the present invention will vary accordingly within any 24-hour period. The natural gas initially contains 60,000 ppm of H2S and about 160,000 ppm of CO2, as well as several other contaminants, including water, salts, other sulfur-containing compounds (such as mercaptans and thiophenes), BTEX chemicals and metals. The reaction chamber volume of the reactor or bubbling tower 100 used in the treatment method is about 1000 U.S. gallons and is initially filled with about 600 U.S. gallons of a new water wash solution having an initial pH of about 11. When the contaminated natural gas is treated by bubbling or by the water wash solution, the pH of the water wash solution is monitored by sensor 116, and whenever the pH drops below a threshold of 10, the used water wash solution in the reaction chamber is updated with a certain amount of fresh water wash solution having a pH of about 11. For this renewal, the pH value is variably prone to drop below 10 every 40 to 90 minutes, and the renewal process includes replacing about 1 / 10 of the total volume of the spent wash solution with fresh wash solution, for example, 60 gallons of spent wash solution are discharged through the discharge port 118, and 60 gallons of fresh wash solution 102 having a pH value of about 11 are introduced through one or more inlets 112, 114.

[0065] The beta test was run continuously for several months without any significant complications, including virtually no clogging of the reactor and associated piping by precipitates. When the treated gas was analyzed, it was shown that the initial H2S content of the gas was reduced from 60% to 80%, the initial CO2 content of the gas was reduced from 50% to 80%, and the salt content of the gas was reduced to essentially 0%.

[0066] The third discovery of the inventors is another new treatment system and method for treating contaminated gases (such as those described herein, including natural gas from wells), which is a hybrid between the water washing method and the continuous treatment method according to the first embodiment described above, wherein the contaminated gas is directly contacted with a liquid treatment composition having a very high concentration of hydroxide (from one or more hydroxides), such as the treatment compositions disclosed in PCT / US2018 / 050913 and PCT / US2018 / 064015 and the '911 and '064 patents and variations thereof, such as the variations discussed with respect to other discussed embodiments of the present invention. The treatment compositions disclosed in PCT / US2018 / 064015 and the '911 and '064 patents include small amounts of organic acids (such as fulvic acid and humic acid), such as 0.01 wt % to 3.0 wt %, to help prevent the release of precipitates and solids from the treated liquids and gases, and based on the third discovery of the inventors, the amounts of these organic acids are suitable for treatment methods according to exemplary embodiments of the present invention. The reactions between the treatment composition and the contaminated gas can be the same as those discussed with respect to the first embodiment of the present invention, noting that hydroxide is the primary reactant in the improved water wash and treatment compositions disclosed in PCT / US2018 / 050913 and PCT / US2018 / 064015 and the '911 and '064 patents. In this new treatment method and system, the contaminated gas flows through the conduit, and a portion of the conduit is effectively used as a reaction chamber, where the contaminated gas is continuously remediated. Figure 4 is a schematic diagram of a processing system for remediating polluted gas according to another exemplary embodiment of the present invention based on the third discovery of the inventors; Figure 5 According to the present invention, Figure 4 A flow chart of an exemplary embodiment of a process for remediating a contaminated gas by a processing system. Figure 4 The treatment method can be operated on a continuous basis wherein the contaminated gas flows continuously or substantially continuously through a pipeline while quantities of a treatment composition and water are respectively injected into portions of the pipeline for treating the gas to remediate and remove contaminants from the gas, and as the treated contaminated gas continues to flow, the treated gas is rapidly separated from the treatment composition, water, and any precipitates and solids released from the treated contaminated gas.

[0067] exist Figure 4 In the treatment method of the present invention, the amount of liquid treatment composition injected into the flowing stream of contaminated gas in the pipeline is based on the amount of contaminated gas to be treated and the type and amount of contaminants in the contaminated gas. Any volume of contaminated gas can be treated, but for natural gas from one or more wells that are usually collected together at a given location, a typical daily production of contaminated natural gas may be 500,000 ft 3Up to 5,000,000ft 3 , and the contaminants may include varying amounts of salts, CO2, H2S, SO2, other sulfur-based contaminants (including mercaptans and thiophenes), and metals. Technically, water may also be considered a contaminant in the gas, but for purposes of this disclosure, water is not considered to be one of the contaminants to be remediated. In order to treat this volume of contaminated natural gas, as well as other contaminated gases, the inventors have determined that the appropriate amount of treatment composition (such as those disclosed in PCT / US2018 / 050913 and PCT / US2018 / 064015, '911 and '064 patents, and variations thereof) is in the range of 1 US gallon / hour to 150 US gallons / hour. Due to the high concentration of hydroxides therein, these compositions typically have a pH of 14. In this new treatment method, water is injected into the contaminated gas flowing in the pipeline separately from the treatment composition, preferably downstream of the injection of the treatment composition, although the water can be injected upstream or upstream and downstream of the treatment composition. The amount of water injected into the pipeline can be the same or substantially the same as the amount of the treatment composition injected, but in order to flush the precipitate and solid released from the treated gas along the pipeline to prevent any accumulation of these materials in the pipeline, the amount of water injected into the pipeline can be significantly larger. The most suitable amount of the treatment composition to be used can be determined by pH, pKa and / or other characteristics of the treated polluted gas and / or liquid in the monitoring separator, and the treatment system and / or method can be appropriately adjusted based on the characteristics monitored. Similarly, the most suitable amount of water to be used can be determined based on the accumulation of any precipitate and solid that occurs in the pipeline, and can be appropriately adjusted based on this. This adjustment can include adjusting the amount of the treatment composition injected in the treatment step, adjusting the amount of water injected, adjusting the position of the pipeline injecting treatment composition and / or water, etc., as further discussed herein.

[0068] refer to Figure 4 , shows a processing system 200 according to an exemplary embodiment of the present invention. The system 200 generally includes: a pipeline 202, Figure 4, the contaminated gas passes through the system from left to right via conduit 202; a coalescer 204, which can be used to remove some impurities from the contaminated gas as it enters the system; a main treatment section 206 of the conduit, in which a treatment composition and water are injected to react with the gas as a main treatment to repair and remove most of the contaminants in the gas, including salts, CO2, H2S, other sulfur-based contaminants (including mercaptans and thiophenes), metals, SO2, NH3, etc.; a first separator 208, which separates the treated contaminated gas from liquids, precipitates and solids released by the treatment in the main treatment section 206 of the conduit; a first separator 208, which separates the treated contaminated gas from liquids, precipitates and solids released by the treatment in the main treatment section 206 of the conduit; a first separator 208, which separates the treated contaminated gas from liquids, precipitates and solids released by the treatment in the first treatment section 206 of the conduit; a first separator 208, which separates the ... a second treatment portion 210 of the pipeline in which the treated contaminated gas is treated a second time to remove most or all of the residual contaminants in the already treated contaminated gas, which may include H2S and CO2; a second separator 212, which separates the twice treated contaminated gas from liquids, precipitates and solids released by the treatment in the second treatment portion 210 of the pipeline; and a waste discharge pipeline 215, into which the liquids and solids separated from the contaminated gas in the agglomerator 204, the first separator 208 and the second separator 212 can be discharged for disposal or further treatment.

[0069] The system 200 may be automated using a controller 214 that receives various inputs from sensors that sense the flow rates of the polluted gases, treatment compositions, and water entering and passing through the system 200, as well as other sensors that monitor the properties of the polluted gases, treatment compositions, and water at various locations in the system (including pH, pKa, etc.), and controls various valves disposed at various locations in the system that control the flow rates of polluted gases and liquids entering and exiting the system. Such valves may be solenoid-controlled valves. The controller 214 may be an electronic control unit (ECU) programmed to control the system 200, and may include a memory (not shown) that stores predetermined data, such as the appropriate amounts of treatment compositions and water to be injected based on the flow rates and the amount of contamination in the polluted gases, etc. For example, Figure 4 As shown, there may be provided a valve 216 to control the flow of contaminated gas into the system, a valve 218 between the coalescer 204 and the main treatment section 206 of the pipeline to control the flow of contaminated gas into the section 206, a valve 220 to control the flow of treated contaminated gas from the section 206 into the first separator 208 at the end of the main treatment section 206 of the pipeline, a valve 222 to control the flow of treated contaminated gas from the system, and valves 224, 226 and 228 provided along the waste discharge line 215 to control the discharge of liquids and solids from the coalescer 204, the first separator 208 and the second separator 212. Other valves may be provided in the system as desired or required, although these valves are not shown in the drawings. Figure 4, for example, valves for controlling the injection of treatment composition and water into the system at various locations, such as locations 232, 234 in the main treatment portion 206 of the pipeline 202 and location 236 in the second treatment portion 210 of the pipeline, note that the locations of these treatment portions of the pipeline where the treatment composition and water are injected can be varied as needed or desired to most efficiently and effectively treat the contaminated gas, as further discussed herein.

[0070] The sensor may include a flow meter 230 disposed at the inlet of the conduit 202 for sensing the flow rate of the contaminated gas entering the system 200, even though the flow rate may vary while the treatment system is continuously running. Figure 4 Not shown, but other flow sensors may be provided to determine the flow rate of contaminated gas after it is treated and released in different parts of the system, as well as the flow rate of treatment composition and water injected into the system, although the volume of contaminated gas entering the system should be approximately the same as the volume of gas passing through different parts of the system. The sensors may also include pH and / or pKa sensors disposed at several locations in the system, for example, a sensor 238 for sensing contaminated gas entering the main treatment section 206, a sensor 240 for sensing treated contaminated gas, treatment composition, and water at various locations in the main treatment section 206, a sensor 242 for sensing treated contaminated gas, treatment composition, and water entering the first separator 208, a sensor 244 for sensing the already treated contaminated gas discharged from the first separator, a sensor 246 for sensing the treated contaminated gas and treatment composition in the second treatment section 210, a sensor 246 for sensing the twice treated contaminated gas discharged from the second separator 212, sensors 248, 250, and 252 for sensing fluids in the coalescer 204, the first separator 208, and the second separator 212, respectively, and sensors 254, 256, and 258 for sensing liquids and solids in the waste discharge line 215 downstream of the coalescer 204, the first separator 208, and the second separator 212, respectively. Other sensors may be provided as desired or required.

[0071] Pipeline 202, including the sections of pipeline used as primary processing section 206 and secondary processing section 210, may be of any size / diameter suitable for processing a contaminated gas flow, for example, if processing contaminated natural gas from one or more wells, a flow rate of 500,000 ft 3 / day up to 5,000,000ft 3 / day, and the amount of treatment composition and water injected into the pipeline to treat the polluted gas, such as 1 to 150 U.S. gallons per hour for each treatment composition and water. The pipeline can be made of any suitable material (such as steel, stainless steel, galvanized steel, etc.). The specific volume of the polluted gas will also change according to the pressure of the gas, and it is noted that the higher the pressure, the smaller the volume and flow rate of the gas. This is very important because the flow rate of the polluted gas affects its contact time with the treatment composition. The polluted gas should have enough contact time with the liquid treatment composition for proper repair, such as 0.2 seconds to 5.0 seconds, preferably at least 0.5 seconds. The typical pressure of the polluted natural gas from the well is 35PSI to 100PSI, although the pipeline 202 and other components of the system can handle higher pressures, such as 1800PSI. The system can operate at any suitable temperature, such as ambient temperature or higher temperature. The polluted natural gas from the well may be at a temperature of 65°F to 100°F.

[0072] Coalescer 204 may be sized to handle a certain volume of polluted gas and may be used to remove some impurities from the polluted gas as it enters the system. A coalescer is a separator used to remove some types of contaminants, such as some water and some relatively large impurities, such as sand, from the polluted gas. The coalescer may include a sight glass 260 for an operator to observe. Depending on the amount and type of contaminants in the polluted gas, coalescer 204 may be omitted.

[0073] The main treatment section 206 of the pipeline is actually a reactor in which the polluted gas is treated with a treatment composition and water, and it can have any suitable length, such as 10 feet to 50 feet. The treatment composition can be injected at different locations of the section 206, which provides flexibility for achieving the best results. The amount of the treatment composition and water injected into the main treatment section will vary according to the amount of polluted gas to be treated and the type and amount of pollutants in the gas. The most suitable amount of the treatment composition and water can be determined based on the pH or pKa of the treated polluted gas entering the first separator 208 or in the first separator 208. Typically, the treatment composition can be exhausted very quickly after being injected into the main treatment section 206 and mixed with the polluted gas, such as in less than one second, and the pH of the mixed fluid in the first separator 208 can be 9 to 11. It is hoped that the pH of the fluid in the first separator does not exceed 11, because this will indicate that the treatment composition is not completely exhausted substantially, and the waste discharged from the first separator may contain a large amount of unused treatment composition. The treatment composition can be injected into the section of the pipeline as fine droplets by a suitable syringe so that the treatment composition is quickly mixed into the polluted gas. The water can also be injected in the form of fine droplets via a suitable syringe.

[0074] The amount of treatment composition to be injected can be adjusted according to the desired pollution reduction level, for example, 40-80% by weight and / or volume % of pollutants can be repaired or removed according to the amount of treatment composition used. If the treated polluted gas will be accepted for use or further treatment at a lower level of pollution reduction, it may be desirable to achieve a lower level of pollution reduction. For polluted natural gas from a well, the main purpose may be to make the well run simply, and if it is allowed to run at a lower pollution reduction level, this may be desirable because the cost is lower based on the use of less treatment composition. If it is desired to remove as many pollutants as possible in the main processing section 206, it is desired to inject as much treatment composition as possible when the pH of the mixed fluid in the first separator does not exceed 11. In addition, when the system is operated on a continuous basis, the flow rate of the polluted gas may change, thereby it may be necessary to adjust the flow rate of the treatment composition based on the flow rate of the gas.

[0075] The flow rate of water injected into the main treatment section 206 of the pipeline can be similar to the flow rate of the treatment composition, but it can also be different. Water can be injected into the main treatment section 206 at a location upstream and / or downstream of the location where the treatment composition is injected, but the downstream location is particularly suitable because the main function of the injected water is to completely flush any precipitates and solids released from the treated polluted gas through the main treatment section 206 and into the first separator 208. The inventors have determined that if water is injected upstream of the treatment composition injection location compared to the downstream injection of water at the treatment composition injection location, twice the treatment composition may be required to achieve a given level of pollution reduction. If it is desired or necessary to ensure that precipitates and solids do not accumulate in the main treatment section, the flow rate of the water can be increased to be higher than and significantly higher than the flow rate of the treatment composition, for example, the flow rate of the water can be increased to 10 times or more of the amount of the treatment composition, at least periodically for a short period of time, such as one minute or less, to ensure that the main treatment section 206 of the pipeline 202 is properly flushed, thereby preventing the accumulation of any precipitates and solids. The water used in the system can be potable water, which is advantageous because potable water can absorb more of the precipitates and solids released from the treated contaminated gas, including salts, although other waters, such as surface water, can be used if potable water is not available. As in the treatment methods according to other embodiments of the present invention discussed herein, the water can also include antimicrobial agents, such as copper sulfate and potassium silicate, particularly if potable water is not available.

[0076] The distance between the location where the treatment composition is injected into the main treatment section 206 and the location where the water is injected into the water injection section 206 depends on several factors, such as the speed at which the polluted gas flows in the pipeline, and the type and amount of pollutants in the gas. The inventors have determined that a contact time of at least 0.2 seconds, preferably at least 0.5 seconds, is sufficient to allow the treatment composition to fully repair a large amount (e.g., 50-80% by weight) of the polluted gas while substantially exhausting most of the reactivity of the treatment composition. Therefore, if the polluted gas flows at a speed of 3-10 ft / second, the distance between the treatment composition and the location where the water is injected into the pipeline can be 0.6-3.0 feet. In general, the distance should be at least 3 inches to 5 inches. The water injected into the pipeline will dilute any residual amount of the treatment composition so that the treatment composition can continue to repair the residual pollutants until all the fluids are separated in the first separator 208. The precipitates released from the polluted gas may include salts, carbonate crystals, sulfur, sulfur-containing compounds, metals, etc., and the precipitates will generally flow into the first separator 208 with the injected water and liquid treatment composition, and the treated polluted gas is separated from these liquids and precipitates in the first separator 208.

[0077] If water is injected into the portion 206 downstream of the treatment composition injection location, the distance between the most downstream point of water injection and the first separator 208 may vary, but it is generally desirable to quickly separate the treated contaminated gas from the liquid and sediment after the treatment composition and water are injected into the main treatment portion 206, so this distance may be as little as 1 foot to 25 feet. This distance also applies if the treatment composition is injected into the portion 206 downstream of the water injection location.

[0078] The first separator 208 may be a two-phase scrubber. After the treated polluted gas, liquid and sediment enter the first separator, the treated polluted gas is discharged into the pipe 202 at the upper part of the separator and flows into the second processing part 210 of the pipe, while the liquid, sediment and solid are discharged into the waste discharge line 215 at the bottom of the separator to be disposed of or collected and further processed if necessary. It is desirable that the treated polluted gas contains as little liquid as possible, so a baffle 264 or the like may be provided to remove liquid from the treated gas before the treated gas is discharged into the pipe 202. The first separator 208 may include a sight glass 262.

[0079] The second treatment section 210 of the pipeline may not be as long as the main treatment section 206 because most of the original contaminants in the treated contaminated gas have been removed when the treated contaminated gas enters section 210, so when the gas is secondarily treated in section 210, much less sediment and solids will be discharged from the once treated contaminated gas. For example, section 210 can be 1 / 2 the length of section 206. In addition, the treatment composition can be injected only into section 210, because this may be sufficient to prevent any accumulation of sediment and solids in section 210. However, if desired, both the treatment composition and water can be injected into the second treatment section 210 of the pipeline 202. The amount of treatment composition added to the second treatment section 210 can be significantly less than the amount of treatment composition added to the main treatment section 206, for example, for the same amount of gas, ≤ 1 / 5 of the amount injected into the main treatment section, because most of the contaminants have been repaired / removed from the contaminated gas in the first treatment section 206. If water is also injected into the second treatment section 210, a smaller amount of water may again be injected than the amount of water injected into the main treatment section 206, for example, ≤ 1 / 5 of the amount of water injected into the main treatment section for the same amount of gas. The relative distances between the location where the treatment composition and water are injected into the second treatment section 210, and the relative distance between the last injection location in the second treatment section and the second separator may be substantially the same as discussed with respect to the main treatment section 206 and the first separator. However, if only the treatment composition is injected into the second treatment section 210, the primary consideration for adjustment is the distance between the composition injection section 210 and the second separator 212.

[0080] The second treatment section 210 can effectively remove all or substantially all residual pollutants in the once-treated polluted gas that has been treated in the main treatment section 206. How many residual pollutants are removed in the second section 210 is variable, depending on how many treatment compositions are injected into the gas when the gas passes through the section 210. Similarly, for cost or other considerations, it may not be necessary to remove all residual pollutants. In addition, if the pollutant reduction amount realized in the main treatment section 206 and the first separator is enough, the second treatment section 210 and the second separator 212 can be omitted from the system. The most suitable amount of treatment composition and water to be injected into the second treatment section 210 can be determined based on the pH or pKa of the treated polluted gas entering the second separator 212 or in the second separator 212. Similar to the main treatment section 206, the treatment composition is exhausted very quickly after being injected into the second treatment section 210 and mixed with the polluted gas, for example, in less than one second. The pH of the mixed fluid in the second separator 212 can be 10 to 11. It is desirable that the pH of the fluid in the second separator does not exceed 12 as this would indicate that the treatment composition is not substantially completely depleted and that the waste discharged from the first separator may contain significant amounts of unused treatment composition.

[0081] The second separator 212 may be a two-phase scrubber or a two-phase baffle separator. After the twice treated polluted gas, liquid and sediment enter the second separator 212, the gas is discharged into the pipe 202 at the upper part of the second separator and can be discharged from the system 100 for direct use or further treatment, while the liquid, sediment and solid are discharged into the waste discharge line 215 at the bottom of the separator for disposal or collection and further treatment if necessary. It is desirable that the twice treated polluted gas discharged from the second separator contains as little liquid as possible, so a baffle or the like (not shown) may be provided to remove liquid from the treated gas before the treated gas is discharged into the pipe 202. The second separator 212 may include an observation mirror 262.

[0082] refer to Figure 5 , showing the use of the present invention Figure 4Flow chart of an exemplary embodiment of a continuous treatment method for remediating contaminated gas by a treatment system. In step S21 of the treatment method, the contaminated gas is introduced into the pipeline as a flowing gas stream. If a coalescer 204 is used, in step S22, the gas stream flows into the coalescer, so that some contaminants, such as sand and some water, can be removed from the gas. In step S23, the contaminated gas flows into the main treatment portion 206 of the pipeline, and in step S24, a treatment composition (such as PCT / US2018 / 050913 and PCT / US2018 / 064015 and any of those disclosed in the '911 and '064 patents and variations thereof) is injected into the gas at an appropriate location in the main treatment portion 206 at an appropriate rate (depending on the flow rate and characteristics of the contaminated gas) as described herein, so that the liquid treatment composition is mixed into the contaminated gas in the flowing stream and remediates the contaminants in the contaminated gas, and in step S25, water is injected into the gas at an appropriate location downstream of the injection of the treatment composition in the main treatment portion 206 at an appropriate rate (depending on the flow rate and characteristics of the contaminated gas) as described herein, so that the water is also mixed into the contaminated gas and the treatment composition in the flowing stream and helps to flush the treatment composition, the treated gas and any precipitates and solids released from the treated gas through the main treatment portion 206 and into the first separator 208. At step S26, the pH characteristics of the mixture of treated polluted gas, treatment composition, water, precipitate and solids are monitored, and if necessary, the amount and injection location of the treatment composition and water can be adjusted at step S27. At step S28, the treated polluted gas is separated from the liquid and solid in the first separator 208, so that the treated gas flows into the second treatment section 210 of the pipeline, while the liquid and solid materials are discharged to the waste discharge line 215. If sufficient pollutant reduction is achieved in the main treatment section 206, the method can be terminated at this time.

[0083] If a second treatment section 210 and a second separator 212 are included and used for a second treatment of the contaminated gas, at step S29, the contaminated gas discharged from the first separator 208 flows into the second treatment section 210 of the pipeline 202, and at step S30, a treatment composition (which may be the same or different than the treatment composition injected into the main treatment section 206) is injected into the gas at an appropriate location in the second treatment section 210 at an appropriate rate as described herein, so that the liquid treatment composition mixes into the contaminated gas in the flowing stream and further remediates any contaminants remaining in the contaminated gas. If any water is required to flush the second treatment section 210, then at step S31, water is injected into the gas at an appropriate location in the second treatment section 210 at a certain rate as described herein, so that the water also mixes into the contaminated gas and treatment composition in the flowing stream and helps flush the treatment composition, the treated gas, and any precipitates and solids released from the treated gas through the second treatment section 210 and into the second separator 212. Likewise, water is optional for the second treatment section 210, so step S31 can be omitted so that only the twice treated polluted gas, the treatment composition, and any further precipitates and solids released from the twice treated gas flow into the second separator 212. If the treatment composition includes an organic acid as described herein (e.g., fulvic acid and humic acid), little or no precipitates and solids are released from the twice treated gas in the second treatment section 210. In step S32, the pH characteristics of the mixture of twice treated polluted gas, treatment composition, water, precipitates, and solids entering or in the second separator 212 are monitored, and if necessary, the amount and injection location of the treatment composition and / or water in the second treatment section 210 can be adjusted based on the pH in step S33. In step S34, the treated polluted gas is separated from the liquids and solids in the second separator 212, so that the treated gas flows into the pipeline 202, and the liquid and solid materials are discharged into the waste discharge pipeline 215 for disposal or further treatment. The secondary treated contaminated gas exhausted from the second separator 212 may be substantially free of any contaminants, and the process may terminate at this point.

[0084] according to Figure 5 The processing system and method of the exemplary embodiment of the present invention are shown, using Figure 4 The exemplary embodiment of the treatment system shown has advantages over conventional known treatment systems and methods for treating contaminated gases. Using this novel method, the inventors have been able to successfully treat highly contaminated gases (including natural gas) in a practical, cost-effective manner in a continuous treatment process that is not possible with conventional known treatment systems and methods. For example, the inventors have been able to treat large quantities of highly contaminated natural gas (e.g., 500,000 ft per day) 3 Up to 5,000,000ft3 The new treatment system and method was implemented by the US Patent and Trademark Office (hereinafter referred to as the "Office of the Administration") and achieved 40% to almost 100% remediation of the contaminants in an efficient and cost-effective manner. In contrast, this highly contaminated natural gas could not be treated in a practical and cost-effective manner using conventional known treatment systems and methods. The owners of wells that output highly contaminated natural gas are essentially forced to shut down these wells because they cannot treat the highly contaminated natural gas in a practical and cost-effective manner, and thus the owners cannot extract the crude oil that would be output from the same wells along with the highly contaminated natural gas.

[0085] In addition, the treatment system and method according to this exemplary embodiment are very flexible in the extent to which pollutants in highly polluted gases, including natural gas, are repaired using the new system and method. For example, in the treatment of highly polluted natural gas, the inventors are able to adjust the system and method to achieve different degrees of repair, which is desirable in any given situation. For polluted natural gas, it is usually sufficient to reduce the level of pollutants (especially H2S) by 40-80 weight % or volume % to make the polluted gas accepted by the refinery, and the refinery will further repair the pollutants as needed or desired. Although this partially repaired natural gas may still be considered to have a high sulfur content, it can be extracted from the well and sold for use or further refining, and the ability to extract natural gas also allows crude oil to be extracted from the well. In addition, if the first processing step and the first separation step of the main processing section 206 and the second processing section 210 and the second processing step and the second separation step are used, complete or almost complete repair of pollutants in highly polluted natural gas can be achieved. Therefore, the repair level achieved by the treatment system and method can be easily adjusted according to the needs and expectations of consumers.

[0086] It will be appreciated that treatment methods using alkaline water wash solutions according to embodiments of the present invention can be effectively and economically used to remove contaminants from a variety of contaminated gases. Again, the natural gas industry is a primary example, noting that prior to the present invention there were no known conventional methods that could effectively treat some highly contaminated natural gas from existing wells and known underground reservoirs in a practical, cost-effective manner, and thus there are many closed wells and untapped reservoirs in the world. Another type of contaminated gas that can be effectively and cost-effectively treated using alkaline water wash solutions according to embodiments of the present invention is combustion gases from fossil fuels (e.g., coal) and petroleum-based liquids and gases (such as those used in various industries including power plants), which typically contain large amounts of CO2, SO2, etc. Thus, for example, this treatment method can be cost-effectively used as a carbon sequestration / carbon mitigation strategy, noting that if a power plant burning fossil fuels produces thirteen million (130) million ft 3A combustion gas containing 80,000 ppm CO2 is continuously output at a rate of 100 ppm / day and treated with this process, which would remove 57,058 kg or 63 tons of CO2 from the gas every day. Currently, the government rewards industry with carbon credits for reducing CO2 emissions, which is equivalent to a large sum of money. The same principle applies to SO2 and other pollutants that are usually contained in the gas.

[0087] The foregoing description is given for clearness of understanding only, and no unnecessary limitations are to be understood therefrom, since modifications within the scope of the invention will be obvious to one skilled in the art, and such modifications are covered by the appended claims.

Claims

1. A method for removing and / or remediating pollutants in polluted gas, comprising the following steps: passing a stream of polluted gas through the conduit; treating a flowing stream of contaminated gas by injecting droplets of an aqueous liquid treatment composition comprising 35-55 weight percent in total of one or more hydroxide compounds into the contaminated gas stream flowing in a conduit such that the liquid treatment composition mixes into the contaminated gas in the flowing stream and remediates contaminants in the contaminated gas; injecting water into the mixed flow of polluted gas and liquid treatment composition in the pipeline downstream of where the liquid treatment composition is injected into the pipeline; and The flowing stream of treated contaminated gas is separated in a separator from any residual amounts of liquid treatment composition, water and any precipitates and solids released from the contaminated gas during the treatment step.

2. The process of claim 1 wherein the process is run in a continuous manner with a contaminated gas stream of 500,000 ft 3 / day up to 5,000,000ft 3 / day, the amount of treatment composition injected in the treating step is 1 US gallon / hour to 150 US gallons / hour, and the amount of water injected in the water injecting step is 1 US gallon / hour to 150 US gallons / hour.

3. The treatment method of claim 1, wherein the aqueous liquid treatment composition further comprises 0.005 wt% to 3.0 wt% of at least one of fulvic acid and humic acid.

4. The treatment method of claim 1, wherein the aqueous liquid treatment composition comprises a total of 45-55 wt% of one or more hydroxides.

5. The treatment method according to claim 1, wherein the distance between the pipeline location where the aqueous liquid treatment composition is injected in the treatment step and the pipeline location where water is injected in the water injection step is based on the flow rate of the polluted gas in the pipeline, and the distance is sufficient to allow the polluted gas to contact the aqueous liquid treatment composition for 0.2 seconds to 1.0 seconds before injecting water in the water injection step.

6. The treating method of claim 1, wherein the distance between the location of the pipe where the aqueous liquid treating composition is injected in the treating step and the location of the pipe where the water is injected in the water injecting step is at least 3 inches.

7. The treatment method of claim 1, wherein the distance between the location of the pipeline into which the water is injected in the water injection step and the separator is 1 to 25 feet.

8. The processing method according to claim 1 further comprises the following steps: Monitor the pH of the treated contaminated gas, the aqueous liquid treatment composition, and the water entering or in the separator; and adjust at least one of the amount of the aqueous liquid treatment composition injected in the treatment step, the amount of water injected in the water injection step, the pipeline position for injecting the aqueous liquid treatment composition in the treatment step, and the pipeline position for injecting water in the water injection step based on the monitored pH.

9. The processing method according to claim 1 further comprises the following steps: The amount of water injected into the pipe is increased periodically over a period of less than 5 minutes.

10. The processing method according to claim 1, further comprising the following steps: secondary treating the treated contaminated gas after it is discharged from the separator into the conduit by injecting droplets of an aqueous liquid treatment composition into a portion of the conduit downstream of the separator so that the liquid treatment composition mixes with the already treated contaminated gas in the flowing stream and further remediates the contaminants in the already treated contaminated gas; The flowing stream of the secondary treated contaminated gas is separated in a second separator from any residual amounts of liquid treatment composition and any precipitates and solids released from the secondary treated contaminated gas during the secondary treatment step.

11. The treatment method of claim 10, wherein the distance between the location of the pipeline where the treatment composition is injected in the secondary treatment step and the second separator is 1 to 25 feet.

12. The treatment method according to claim 10, wherein the amount of the treatment composition injected in the secondary treatment step is less than or equal to 1 / 5 of the amount of the treatment composition injected in the treatment step.

13. The process of claim 2, wherein the contaminated gas is natural gas from a well.

14. A treatment system for removing and / or remediating contaminants in a polluted gas, comprising: a conduit configured to receive a flow stream of contaminated gas therethrough; A portion of the conduit has at least one injection port through which droplets of an aqueous liquid treatment composition comprising a total of 35-55 weight percent of one or more hydroxides can be injected into a contaminated gas stream flowing in the conduit so that the aqueous liquid treatment composition mixes with the contaminated gas in the flowing stream and remediates contaminants in the contaminated gas; the portion of the conduit having at least one other injection port through which water droplets can be injected into the conduit so that the water mixes with the contaminated gas stream and the aqueous liquid treatment composition flowing in the conduit, the at least one other injection port being located downstream of the location of the at least one injection port; and A separator is located downstream of the location of the at least one injection port and is configured to separate the flow stream of treated contaminated gas from any residual amounts of liquid treatment composition, water, and any precipitates and solids released from the contaminated gas.

15. The processing system of claim 14, wherein: The pipeline distance between the at least one injection port and the at least one other injection port is determined based on the flow rate of the contaminated gas flowing through the pipeline and is sufficient to allow the contaminated gas to contact the aqueous liquid treatment composition injected through the at least one injection port for 0.2 seconds to 1.0 seconds before water is injected through the at least one other injection port.

16. The processing system of claim 14, wherein: The conduit distance between the at least one injection port and the at least one other injection port is at least 3 inches.

17. The processing system of claim 14, wherein the at least one other injection port is located at a distance of 1 to 25 feet from the separator.

18. The processing system of claim 14, further comprising: a second portion of the conduit, located downstream of the separator and having at least one injection port through which droplets of an aqueous liquid treatment composition can be injected into the contaminated gas stream flowing in the conduit so that the aqueous liquid treatment composition mixes with the contaminated gas in the flowing stream and further remediates the contaminants in the contaminated gas; and A second separator is located downstream of the second portion of the conduit and is configured to separate the flowing stream of treated contaminated gas from any residual amounts of liquid treatment composition and any precipitates and solids released from the further remediated contaminated gas.

19. The treatment system of claim 18, wherein the second portion of the conduit is located at a distance of 1 to 25 feet from the second separator.

20. The processing system of claim 14, wherein there is more than one of said at least one injection port and there is more than one of said at least one other injection port.

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