Method and apparatus for treating liquid feed in separation system

Abstract

An apparatus and method of treating a liquid feed in a separation system is described herein. CO₂ is purified and SO₂ and solvent are captured from the liquid feed in a distillation column. A portion of the purified CO₂ is supplied back to the distillation column in a reflux stream while a majority of the purified CO₂ is delivered to a storage container. Captured solvent and SO₂ from the distillation column are supplied to a scrubber column wherein the captured solvent and SO₂ are treated therein. SO₂ is scrubbed in the scrubber column while the treated solvent from the scrubber column is delivered to a solvent dryer to produce a dry solvent for subsequent recycling.

Description

METHOD AND APPARATUS FOR TREATING LIQUID FEED IN SEPARATION SYSTEMBACKGROUNDField of the Invention

[0001] The present disclosure relates generally to a method and apparatus for an advanced separation system for a back end of a pollutant capture process. More specifically, the present disclosure relates to a method and apparatus for treating a liquid feed at the back end of ultralow temperature pollutant capture process(es) for generating and producing CO2 purification, SO2 scrubbing and solvent recovery and drying.Background of the Invention

[0002] An industrial separation system, such as those at the back end of a pollutant capture process, may refer to the equipment or series of processes that separate and purify the captured pollutants or target compounds (like CO2, SO2, NOX, particulates, etc.) from other substances after they’ve been removed from the main exhaust stream. Thus, a goal of the back-end separation system may include: isolating the captured pollutant (e.g., carbon dioxide from amine solutions); regenerating or recycle solvents or sorbents; and / or preparing the pollutant for storage, reuse, or disposal. In short, the back-end separation system enables reuse of capture materials and prepares the pollutant stream for downstream handling, such as compression, transportation, or conversion into a saleable product.

[0003] Post-combustion carbon dioxide (CO2) capture refers to the removal of CO2 from flue gases after the combustion of fossil fuels. This method is commonly used in power plants and industrial facilities to reduce greenhouse gas emissions. However, the effectiveness and longevity of traditional CO2 capture technologies — particularly solvent-based systems such as amine scrubbing — are highly dependent on the quality and composition, (as amines degrade rapidly in the presence of SO2) of the flue gas entering the system.

[0004] Flue gas from combustion processes typically contains a range of pollutants including nitrogen oxides (NOX), sulfur oxides (SOX), and particulate matter, which can degrade or poison CO2 capture materials and solvents. Therefore, upstream pollutant control systems are essential prerequisites for carbon capture: Selective Catalytic Reduction (SCR) is used to reduce NOXemissions; Flue Gas Desulfurization (FGD) removes sulfur dioxide (SO2); Electrostatic Precipitators (ESP) or fabric filters remove particulate matter.

[0005] Facilities that burn high-sulfur fuels (e.g., heavy fuel oil or sour natural gas) and lack these pollutant control systems are not suitable for traditional carbon capture deployment. In such cases, corrosive or contaminant-laden flue gas can cause operational issues, damage equipment, and significantly increase maintenance and solvent replacement costs.

[0006] As a result, effective post-combustion CO2 capture generally requires integration with a suite of upstream emissions control technologies to ensure both environmental compliance and the technical viability of the carbon capture system.SUMMARY

[0007] According to first broad aspect, the present disclosure provides a separation system comprising: a distillation column operatively connected to a liquid feed; a storage container operatively connected to the distillation column; a scrubber column operatively connected to the distillation column; and a solvent dryer operatively connected to the scrubber column wherein the distillation column is configured to purify CO2 and capture SO2 and solvent from the liquid feed, wherein the distillation column is configured to feed the purified CO2 to the storage container, wherein the distillation column is configured to feed the captured SO2 and solvent to the scrubber column, wherein the scrubber column is configured to scrub the captured SO2 and feed the solvent to the solvent dryer to produce a dry solvent for recycling.

[0008] According to a second broad aspect, the present disclosure provides a method of treating a liquid feed in a separation system comprising: purifying CO2 and capturing SO2 and solvent from a liquid feed in a distillation column to produce purified CO2 and captured solvent and SO2; supplying a portion of the purified CO2 in a reflux stream back to the distillation column; supplying the captured solvent and recovered SO2 from the distillation column to a scrubber column; treating the captured solvent and recovered SO2 in the scrubber column; delivering the treated solvent to a solvent dryer and producing a dry solvent; and scrubbing the captured SO2 in the scrubber column.BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The accompanying drawings, which are incorporated herein and constitute part of this specification, illustrate exemplary embodiments of the invention, and, together with the general description given above and the detailed description given below, serve to explain the features of the invention.

[0010] FIG. 1 illustrates an advanced separation system according to one embodiment of the present disclosure.DETAILED DESCRIPTION OF THE INVENTIONDefinitions

[0011] Where the definition of terms departs from the commonly used meaning of the term, applicant intends to utilize the definitions provided below, unless specifically indicated.

[0012] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of any subject matter claimed. In this application, the use of the singular includes the plural unless specifically stated otherwise. It must be noted that, as used in the specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. In this application, the use of “or” means “and / or” unless stated otherwise. Furthermore, use of the term “including” as well as other forms, such as “include”, “includes,” and “included,” is not limiting.

[0013] For purposes of the present disclosure, the term “comprising”, the term “having”, the term “including,” and variations of these words are intended to be open-ended and mean that there may be additional elements other than the listed elements.

[0014] For purposes of the present disclosure, directional terms such as “top,” “bottom,” “upper,” “lower,” “above,” “below,” “left,” “right,” “horizontal,” “vertical,” “up,” “down,” etc., are used merely for convenience in describing the various embodiments of the present disclosure. The embodiments of the present disclosure may be oriented in various ways. For example, the diagrams, apparatuses, etc., shown in the drawing figures may be flipped over, rotated by 90° in any direction, reversed, etc.

[0015] For purposes of the present disclosure, a value or property is “based” on a particular value, property, the satisfaction of a condition, or other factor, if that value is derived by performing a mathematical calculation or logical decision using that value, property or other factor.

[0016] For purposes of the present disclosure, it should be noted that to provide a more concise description, some of the quantitative expressions given herein are not qualified with the term “about.” It is understood that whether the term “about” is used explicitly or not, everyquantity given herein is meant to refer to the actual given value, and it is also meant to refer to the approximation to such given value that would reasonably be inferred based on the ordinary skill in the art, including approximations due to the experimental and / or measurement conditions for such given value.

[0017] For purposes of the present disclosure, the term “ambient conditions” refers to the surrounding environmental factors of a system or object. These factors may include temperature or room temperature, humidity, air pressure, light intensity, noise level, and vibration magnitude. They essentially describe the "background" conditions of an environment.

[0018] For purposes of the present disclosure, the term “amines” refers to a class of organic compounds characterized by the presence of a nitrogen atom bonded to one or more carbon atoms. They are considered derivatives of ammonia (NH3), where one or more hydrogen atoms have been replaced by organic groups. Amines may play a significant role in various biological and industrial processes and are classified based on the number of carbon atoms directly attached to the nitrogen atom (primary, secondary, or tertiary).

[0019] For purposes of the present disclosure, the term “caustic water” refers to water that contains a high concentration of caustic soda (sodium hydroxide, NaOH). This is a strong base, and in water treatment, it's used to raise the pH, control corrosion, and aid in the removal of certain contaminants.

[0020] For purposes of the present disclosure, the term “distillation column” refers to a piece of equipment in chemical processing, used to separate liquid mixtures into their component parts based on differences in boiling points. It works by heating a mixture and then condensing the vapor, allowing for the collection of different fractions at various points in the column. Thus, a mixture may be heated, and the component with the lowest boiling point vaporizes first. This vapor rises through the column, while the remaining liquid, now richer in higher boiling point components, is collected. Industrial distillation columns are typically tall, vertical cylindrical vessels, often with internal trays or packing to enhance separation and may also be referred to as a fractionating column. In some disclosed embodiments, components of the distillation column may include: Vertical Shell: the main body of the column, typically cylindrical; Reboiler: generally located at the base, it provides heat to vaporize the liquid mixture; Condenser: generally located at the top, it cools the vapor, causing it to condense back into a liquid; Trays or Packing: internal components that provide surfaces for vapor-liquidcontact, enhancing separation; and Feed and Withdrawal Points: locations for introducing the mixture and collecting the separated fractions.

[0021] For purposes of the present disclosure, the term “NNF” refers to normally no flow stream. This is intermittent flow and only required if TDS of water level increased to 1800 ppm wt.

[0022] For purposes of the present disclosure, the term “pH” refers to a scale that measures how acidic or basic a substance is. It ranges from 0 to 14, with 7 being neutral. Values below 7 indicate acidity, while values above 7 indicate alkalinity (or basicity). The pH scale is a measure of the concentration of hydrogen ions in a solution.

[0023] For purposes of the present disclosure, the term “ppm wt” refers to parts per million by weight, and expresses very small concentrations of a substance within a larger mass. It indicates the ratio of the mass of the solute (the substance being dissolved) to the mass of the solution (the mixture), multiplied by one million.

[0024] For purposes of the present disclosure, the term “reboiler” refers to a type of heat exchanger used to provide heat to the bottom of industrial distillation columns. They boil the liquid from the bottom of a distillation column to generate vapors which are returned to the column to drive the distillation separation. The heat supplied to the column by the reboiler at the bottom of the column may be removed by the condenser at the top of the column. Thus, the disclosed reboiler essentially reheats the liquid that has flowed down the column, creating vapor that rises back up to further separate the mixture. In the disclosed embodiment, a purpose of the reboiler (heat exchanger) is to maintain the bottom temperature in the disclosed column to achieve separation of CO2 / i-C5-SO2. In some disclosed embodiments, i-C5 may be regarded as solvent or isopentane.

[0025] For purposes of the present disclosure, the term “reflux” refers to a technique involving the condensation of vapors and the return of this condensate to the system from which it originated. It may be used in industrial and laboratory distillations.

[0026] For purposes of the present disclosure, the term “room temperature” refers to a temperature of from about 20 °C to about 25 °C.

[0027] For purposes of the present disclosure, the term “scrubber column” refers to a type of air pollution control device that uses a liquid (typically water) to remove pollutants from a gas stream. Also known as a packed column scrubber, these columns may be packed withmaterials that increase the surface area for contact between the gas and liquid, enhancing the scrubbing process. Key features and components of an exemplary scrubber column may include: Column: The vertical cylindrical structure that houses the packing and provides a pathway for gas and liquid flow; Packing: materials like raschig rings or intalox saddles (random packing) or structured packing that increase the contact area between the gas and liquid; Liquid Distribution System: ensures the scrubbing liquid is evenly distributed over the packing; Gas Distributor: device that evenly distributes the incoming gas across the column; and Mist Eliminator: located at the top of the column, it removes liquid droplets from the cleaned gas stream. In operation disclosed embodiments may work generally as follows: 1. Gas Inlet: polluted gas enters the column, typically at the bottom of the disclosed scrubber column; 2. Liquid Introduction: scrubbing liquid (water or a chemical solution) is introduced at the top of the scrubber column and flows down through the packing; 3. Contact and Absorption: as the gas flows upwards, it comes into contact with the liquid-wetted packing. Pollutants in the gas stream are absorbed or react with the liquid, effectively removing them; 4. Clean Gas Outlet: the cleaned gas (now with reduced pollutants) exits the column, usually at the top of the scrubber column; 5. Liquid Collection: the liquid containing the pollutants is collected at the bottom of the column and may be treated or disposed of. Thus, the disclosed scrubbers column serves to mitigate air pollution and ensure compliance with environmental regulations.

[0028] For purposes of the present disclosure, the term “solvent” refers to a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid.

[0029] For purposes of the present disclosure, the term “solvent dryer” refers to a device or process used to remove solvents, typically water or other volatile liquids, from a substance, usually a solid, semi-solid, or liquid. This is achieved by evaporation, often facilitated by heat and a drying agent. Solvent drying is an important unit operation in various industries, including pharmaceuticals, food processing, and chemical manufacturing, ensuring product quality and stability. In disclosed embodiments, solvent drying aims to reduce the moisture content of a material to a desired level, which can be crucial for preventing deterioration, improving product properties, or meeting specific quality standards. Disclosed embodiments may employ various methods for solvent drying, including, for examples: Spray drying: atomizing a liquid solution into a hot gas stream, which rapidly evaporates the solvent, leaving behind a dry powder; Vacuum drying: removing moisture by creating a vacuum, lowering theboiling point of the solvent and accelerating evaporation; Desiccants: certain substances, like molecular sieves or chemical drying agents (e.g., calcium chloride, sodium sulfate), can absorb water from solvents; Drum drying: applying a continuous process that uses heated drums to evaporate the solvent from a liquid or slurry; and Freeze drying (lyophilization): employing a specialized method for heat-sensitive materials, where the solvent is sublimated (turned from solid to gas) under vacuum.

[0030] For purposes of the present disclosure, the term “TDS” refers to Total Dissolved Solids (water hardening).

[0031] For purposes of the present disclosure, the term “tempered water” refers to water that has been heated or cooled to a specific temperature range. In some preferred embodiments, tempered water may refer to water with slightly higher temperature from ambient conditions. In this case, the working temperature range may be 45 to 55 °C.Description

[0032] While the invention is susceptible to various modifications and alternative forms, specific embodiment thereof has been shown by way of example in the drawings and will be described in detail below. It should be understood, however that it is not intended to limit the invention to the particular forms disclosed, but on the contrary, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and the scope of the invention.

[0033] Post-combustion capture of carbon dioxide usually requires other upstream pollutant capture systems such as the selective catalytic reduction (SCR) for NOx, flue gas desulfurization (FGD), electrostatic precipitators (ESP), etc. Traditional carbon capture technologies cannot be deployed at point emission sources which do not have these systems and use fuels containing sulfur (e.g., heavy fuel oil, sour gas etc.). The disclosed system proposes a system where all pollutants are captured using a single technology along with CO2 with no additional requirement of SCR or FGD's. The disclosed system has a significantly lower footprint, is energy efficient and maximizes solvent recovery.

[0034] FIG. 1 illustrates an advanced separation system 100 according to one embodiment of the present disclosure. A liquid feed 102 is introduced via connection feed line 104 to a distillation column 106. Distillation column 106 may be regarded as a CO2 purification column. Liquid feed 102 may comprise carbon dioxide (CO2), isopentane(i-C5) and sulfur dioxide(SO2). In some disclosed embodiments, liquid feed 102 may comprise a ternary mixture of captured CO2 and SO2 along with isopentane from a upstream ultra-low temperature pollutant capture process. In some embodiments, liquid feed 102 may comprise a binary mixture of carbon dioxide and isopentane having a range between approximately 60% - 90% of CO2 concentration.

[0035] Distillation column 106 may be operatively connected to condenser 112 such as via connection feed line 108, 110. Coolant 114 is supplied to condenser 112 to condense CO2 using a low temperature utility side operating at a minimum approach temperature of approximately 3 °C. A reflux drum 122 may be operatively connected between condenser 112 via connection feed line 118, 120 and pump 128 (e.g., flux pump) via connection feed line 124. Pump 128 (or reflux pump) transfers the liquid from reflux drum 122 to a top section of distillation column 106. Reflux drum 122 improves the efficiency of CO2 capture in the disclosed design. A function of reflux drum 122 is to collect condensed liquid carbon dioxide (CO2) from condenser 112 and part of the CO2 will send back to the top section of distillation column 106 to maintain a column top temperature to achieve high purity of liquid CO2.

[0036] Thus, in one exemplary design, a small portion of the condensed CO2 in liquid form is configured to be sent back to distillation column 106 as a reflux, and the major portion of the aforementioned condensate condensed CO2 is delivered to a storage container 226 as a final product with a high purity. The small portion of condensed CO2 in liquid form which is sent back to distillation column 106 serves as a reflux for distillation column 106 to cool down the vapors at the top of distillation column 106 in the disclose process of increasing the purity of generated CO2 vapor.

[0037] Pump 128 is configured to pump purified CO2 to storage container 226 via connection feed line 224. Also pump 128 may be configured to pump reflux 138 back to Distillation column 106 via connection feed line 130, 132, 134. A valve 136 (e.g., reflux valve) may be disclosed between pump 128 and distillation column 106 such as along connection feed line 130, 132, 134. Valve 136 facilitates maintaining the flow rate of reflux to distillation column 106 by adjusting the flow rate depending on the speed rate as well as the feed conditions. Disclosed simulated conditions and calculation may also factor in identifying what prescribed rate of flow rate is required for the system.

[0038] In some disclosed embodiments, distillation column 106 may also be operatively connected to a heat exchanger or reboiler 146 that serves as a tempered water supply viaconnection feed line 140, 142, 144. Heat exchanger or reboiler 146 may be fed with a tempered water supply 150 to supply distillation column 106 with tempered water such as via connection feed line 148 (vapor line). In addition, heat exchanger or reboiler 146 may be operatively connected to a scrubber column 160 via connection feed line 154, 158 to supply tempered water 150 thereto.

[0039] Tempered water or hot water enters the heat exchanger or reboiler 146 as a utility through connection at water supply 150 and leaves at connection feed line 144 after exchanging heat energy with shell side process fluid. Process stream enters the heat exchanger or reboiler 146 where a fraction of incoming stream is vaporized and returns back to distillation column 106 via feed line 148 (vapor line). In some disclosed embodiments, tempered water or hot water may be configured to enter the at exchanger or reboiler 146 as a utility through connection at water supply 150 and leave at 152 after exchanging heat energy with shell side process fluid. In a disclosed embodiment, the disclosed tempered water is heated through heat recycled within the disclosed advanced separation system 100.

[0040] Scrubber column 160 may be regarded as an SO2 scrubber column. In some disclosed embodiments, the temperature of tempered water 150 may be set between approximately 45 -55 °C. Valve 156 may be disposed between connection feed line 154 and 158 and act as a pressure reduction valve. In one preferred embodiment, distillation column 106 operates at approximately -49 to -60 °C and at a pressure of approximately 8.5-9.5 barg (depending on feed composition and temperature conditions), while scrubber column 160 operates at approximately 25-35 °C at pressure of approximately 0.2-1.5 barg. However, in some prescribed embodiments, scrubber column 160 may be configured to operate at a pressure of approximately 0.2-0.5 barg. Pressure reduction valve 156 is employed to decrease the pressure of approximately 9.5 barg from distillation column 106 to approximately 1 barg in scrubber column 160 for prescribed field conditions. Thus, the bottom stream of CO2 distillation column 106 mainly contains solvent and SO2 which may be flashed through level control valve 156 at approximately 1.5 barg and sent to the bottom of SO2 scrubber column 160.

[0041] SO2 scrubber column 160 may be operatively connected to condenser 184 via connection feed line 178, 180. Chilled water 182 is supplied to condenser 184. Condenser 184 may be operatively connected to product drum 190 via connection feed line 188. Surge drum 190 is provided for the recovered solvent where the recovered solvent is sent to a solvent dryer200 via transfer pump 216, as explained below. From surge drum 190, wet isopentane (i-C5 + H2O from scrubber column 160) is collected in liquid form along with some non-condensable CO2. A pressure control valve 194 is provided at the surge drum 190 that serves the purpose to recycle back any remaining CO2 to the disclosed upstream carbon capture process. A pressure control valve 194 is operatively connected to surge drum 190 via connection feed line 192. Pressure control valve 194 is configured to provide via connection feed line 196.

[0042] Disclosed embodiments may be configured to shower scrubber column 160 with water. Thus, there may be a chance of water carryover in in the disclosed scrubbed SO2 solvent emanating therefrom. Because disclosed embodiments utilize the scrubbed SO2 solvent at very low temperature forces in the downstream, it is undesirable to have any water carryover in the disclosed downstream process. Thus, the disclosed system is preferably configured to remove any water from the scrubbed SO2 solvent before sending to the downstream process. Hence, the disclosed installed dryer system (e.g., solvent dryer 200) is employed to remove any water from the scrubbed SO2 solvent before sending it downstream for recycling.

[0043] To achieve the same, if there is any non-condensable, in the scrubbed SO2 solvent, it is vented off by using pressure control valve 194. This may occur, for example, in an exemplary configuration designed in an optional direction coming through connection feed line 212 and towards the solvent dryer 200.

[0044] A transfer pump 216 is operatively connected between surge drum 190 via connection feed line 212, 214 and a solvent dryer 200 via connection feed line 210, 198. A purpose of solvent dryer 200 is to remove any water contents in the solvent before send to the disclosed upstream cryogenic process. The water contents in the recovered solvent shall not be more than approximately 1 ppm wt. In some disclosed embodiments, solvent dryer 200 may contain desiccant material in the dryer and may be regarded as a desiccant dryer. Recovered solvent is dehydrated using desiccant in solvent dryer 200 before being recycled back to the disclosed ultra-low temperature pollutant capture process. Transfer pump 216 operates to pump the scrubbed wet solvent to solvent dryer 200.

[0045] A cartridge filter 204 is operatively connected to solvent dryer 200 via connection feed line 202. Cartridge filter 204 removes any fine particles of desiccant carry over along with dry isopentane. Dry solvent 208 may be recycled via connection feed line 206 in the disclosed ultra-low temperature pollutant capture process (ULTP). Since, solvent dryer 200 may contain desiccant material in the dryer, there may be a likelihood of some small particles in the liquidS02 solvent stemming from solvent dryer 200. Such solid particle(s) carry over is undesirable and cartridge filter 204 serves to remove these small solid particles from the liquid SO2 solvent so they do not exist in the downstream system.

[0046] Pump 170 may be operatively connected to a scrubber column 160 via a configuration of connection feed lines 162, 168 and 172, 174, 176. Scrubber column 160 may be regarded as a SO2 scrubber column. A caustic water supply 166 may be introduced and fed via supply line 164 and operatively connected to connection feed line 162, 168. Some of the caustic water from caustic water supply 166 may be supplied through connection feed line 218, 220 as spent caustic water 222 to a waste water supply. Thus, SO2 will be scrubbed by counter current caustic water. The pH of scrubber column 160 will be maintained by injecting 10% caustic solution. Spent caustic water 222 is soiled water that may have some salts and SO2 contents. Disclosed embodiments neutralize this water and treat it before sending it back to the disclosed disposal system. In disclosed designs, this is not a continued stream but rather regarded as a small purge in order to maintain the TDS in the disclosed system. Accordingly, sodium sulfite (Na2SoO3) salt may build up in the advanced separation system 100 due to the mechanism of SO2 scrubbing (washing) or polishing. In order to prevent the scaling and salt deposition in scrubber column 160 internals, a small purge of water will be blow down at the discharge of pump 170 to make sure TDS level in the circulating water shall not be more than 1800 ppm wt.

[0047] In operation, liquid feed 102 may be introduced to distillation column 106 at approximately -60 to -47 °C and 8.5 to 9.5 barg. Advanced separation system 100 will purify the CO2 in a liquid form to generate a purification of approximately 99.95 to 99.99% pure CO2. The CO2 will be recovered, liquified and send to storage container 226 at approximately -40 °C and 10-15 barg. Disclosed processes will also scrub incoming captured SO2 and recover isopentane (solvent) for recycle. In an additional embodiment, disclosed advanced separation system 100 will remove or scrub SO2 from the solvent and eventually dry the same (e.g., at solvent dryer 200), wherein it will be sent back to the disclosed system in a liquid state 208. Thus, the disclosed system may start, for example, from rate of injection in the middle a part of the distillation column 106. Distillation column 106 may comprise two parts. One part of distillation column 106 may comprise a top part which is configured for the purification of CO2. The second part of distillation column 106 may comprise a bottom part for removing any solvent from the remaining CO2. Hence, distillation column 106 may be configured as acondenser reboiler and act as a distillation column. In some disclosed embodiments, distillation column 106 may be configured as a packed bed column with a reboiler and condenser. The pure CO2 will be recovered from distillation column 106 as distillate product, where it is pumped to a storage container 226 as liquid CO2. In one preferred embodiment, the disclosed condenser 112 may be set to work at -49 to -60 °C (depending on feed conditions) in conjunction with distillation column 106.

[0048] In accordance with a disclosed embodiment, any CO2 emanating out from distillation.

[0049] column 106, will be set to condense CO2 at a column operating condition of 9.5 barg with some of the reflux being sent back to the top section of distillation column 106 to maintain the temperature; the majority of purified CO2 in the liquid form is sent to storage container 226 at a prescribed pressure and temperature. In some disclosed embodiments the prescribed pressure the disclosed system is configured to recover and deliver the liquid purified CO2 as a distillate product where it is pumped to the liquid storage container 226 at approximately -40 to -20 °C at 10-20 barg.

[0050] According to some disclosed embodiments, the bottom part of distillation column 106 is provided as a reboiler having a low temperature tempered water utility. An aim of the disclosed embodiment is to purify or remove as much as CO2 from the distillation column 106, because it is not desirable to waste CO2 in the downstream system. Thus, according to disclosed embodiments, distillation column 106 may serve as both a recovery and purification column wherein the bottom part serves as a recovery part and the top part functions as a purification part.

[0051] The bottom stream exiting from the distillation column 106 may will serve as a feed for the scrubber column 160. A purpose of the scrubber column 160 is to scrub SO2 from the solvent received from distillation column 106. The disclosed scrubbing process may be a cross circuit process where disclosed embodiments inject a slightly alkaline water spray, for example, on the top of scrubber column 160, wherein SO2 will react with caustic water and scrub SO2 from the disclosed system. The pH of scrubber column 160 in the disclosed system is maintained by injecting a 10% caustic solution; if there is, for example, a high salt concentration present in the system, disclosed embodiments provide a treatment process to the waste water system, wherein it may be treated. In accordance with a disclosed embodiment, the 10% caustic solution is added in line with scrubber column 160, because incoming SO2will react with NaOH and form sodium sulphite. The injection will be maintained by adjusting the pH level of the bottom contents. A purge of liquid will be discharged to a waste water treatment system such as via spent caustic water 222 to the waste water supply. Thus, an advantage of the disclosed system provides a closed circle system to remove SO2 from the feed gas or from the feed of this process and to, thereby, efficiently scrub SO2.

[0052] From the top of scrubber column 160, wet isopentane or solvent vapor is condensed in condenser 184 by utilizing chilled water 182 at approximately 12-14 °C to produce condensed wet solvent. In doing so, disclosed embodiments employ condenser 184 to achieve predominantly 98-99% of condensed wet solvent with water sent to the drying system (e.g., solvent dryer 200) and eventually sent to be recycled as a dry solvent 208 in the disclosed process. The dry solvent 208 is recovered as a very highly valuable hydocarbon. Thus, a purpose of the disclosed system includes recovering, purifying and drying this hydrocarbon to recycle it back into the disclosed system for reuse.

[0053] Thus, the disclosed system and process covers multiple functions: one is for the purification of CO2; another is for the recovery and scrubbing of SO2; and yet another is for solvent recover and drying. Continued advantages of the disclosed system facilitate a significantly small footprint as an industry standard having low CAPEX (capital expenditure or capital cost). The disclosed system provides a high energy efficient system having a much less utility requirement and low OPEX (operating expenditure or operating cost). At the same time, the disclosed system maximizes solvent recovery and does not require a continuous water feed. Disclosed embodiments provide a low temperature process having a low safety risk while minimizing effluent discharge.

[0054] Having described the many embodiments of the present disclosure in detail, it will be apparent that modifications and variations are possible without departing from the scope of the invention defined in the appended claims. Furthermore, it should be appreciated that all examples in the present disclosure, while illustrating many embodiments of the invention, are provided as non-limiting examples and are, therefore, not to be taken as limiting the various aspects so illustrated.

Claims

WHAT IS CLAIMED IS:

1. A separation system comprising: a distillation column operatively connected to a liquid feed; a storage container operatively connected to the distillation column; a scrubber column operatively connected to the distillation column; and a solvent dryer operatively connected to the scrubber column wherein the distillation column is configured to purify CO2 and capture SO2 and solvent from the liquid feed, wherein the distillation column is configured to feed the purified CO2 to the storage container, wherein the distillation column is configured to feed the captured SO2 and solvent to the scrubber column, wherein the scrubber column is configured to scrub the captured SO2 and feed the solvent to the solvent dryer to produce a dry solvent for recycling.

2. The separation system of claim 1, wherein the distillation column comprises a reboiler and a condenser.

3. The separation system of claim 2, wherein the condenser is configured to operate at 3 °C.

4. The separation system of claim 1, wherein the scrubber column comprises a condenser.

5. The separation system of claim 1, wherein the distillation column is configured to produce 99.98 to 99.99 % purified CO2 delivered to the storage container.

6. The separation system of claim 1, wherein the distillation column is configured to operate at a pressure of 8.5 to 9.5 barg and the scrubber column is configured to operate at a pressure of 0.2-1.5 barg.

7. The separation system of claim 1, wherein the distillation column is configured to receive the liquid feed at -60 to -47 °C at 8.5-9.5 barg.

8. The separation system of claim 1, further comprising:a tempered water supply operatively connected between the distillation column and the scrubber column to supply tempered water to the distillation column and / or the scrubber column.

9. The separation system of claim 8, wherein the tempered water is set at 45 to 55 °C .

10. The separation system of claim 1, wherein the distillation column is configured to receive reflux back to the distillation column.

11. The separation system of claim 10, wherein the reflux comprises purified CO2.

12. The separation system of claim 1, wherein a caustic water supply is operatively connected to the scrubber column.

13. The separation system of claim 12, wherein the caustic water supply is configured to maintain the pH of the scrubber column by injecting a 10% caustic solution.

14. A method of treating a liquid feed in a separation system comprising: purifying CO2 and capturing SO2 and solvent from a liquid feed in a distillation column to produce purified CO2 and captured solvent and SO2; supplying a portion of the purified CO2 in a reflux stream back to the distillation column; supplying the captured solvent and recovered SO2 from the distillation column to a scrubber column; treating the captured solvent and recovered SO2 in the scrubber column; delivering the treated solvent to a solvent dryer and producing a dry solvent; and scrubbing the captured SO2 in the scrubber column.

15. The method of claim 14, wherein the liquid feed is introduced to the distillation column at approximately -60 to -47 °C at 8.5-9.5 barg.

16. The method of claim 14, wherein a portion of the purified CO2 is delivered to a storage container.

17. The method of claim 14, wherein a stream of the captured solvent and SO2 is supplied to the scrubber column at approximately 0.2-1.5 barg.

18. The method of claim 14, wherein a supply of tempered water is distributed to the distillation column and / or the scrubber column.

19. The method of claim 18, wherein a temperature of the tempered water is set at approximately 45-55 °C.

20. The method of claim 14, wherein the distillation column operates at approximately -60 to -47 °C at 8.5-9.5 barg and the scrubber column operates at approximately 25-35 °C at 0.2 -1.5 barg.

21. The method of claim 14, wherein the produced purified CO2 is approximately 99.98- 99.99% pure CO2.

22. The method of claim 14, wherein treating the captured SO2 in the scrubber column comprises: scrubbing the captured SO2 with caustic water to maintain a pH of the scrubber column by injecting a 10% caustic solution.

23. The method of claim 14, wherein the dry solvent is recycled.

24. The method of claim 14, wherein the distillation column comprises a condenser, wherein the condenser is configured to operate at3 °C.

25. The method of claim 14, wherein the purified CO2 is delivered to a storage container at approximately -40 to -20 °C at 10-20 barg.

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