1274results about "Hydrogen sulfides" patented technology

The present invention relates to a pre-passivation process for a continuous reforming apparatus prior to the reaction, or a passivation process for a continuous reforming apparatus during the initial reaction, comprising loading a reforming catalyst into the continuous reforming apparatus, starting the gas circulation and raising the temperature of a reactor, injecting sulfide into the gas at a reactor temperature ranging from 100-650° C., controlling the sulfur amount in the recycle gas within a range of 0.5-100×10⁻⁶ L/L so as to passivate the apparatus.

The process of the present invention may also comprise the following steps:

• • (1) loading a reforming catalyst into the continuous reforming apparatus, starting the gas circulation and raising the temperature of a reactor, feeding the reforming feedstock into the reaction system when the temperature of the reactor is increased to 300-460° C., introducing sulfide into the reaction system while or after the reforming feedstock is fed, controlling the ratio of the total sulfur amount introduced into the system to the reforming feedstock within the range of 0.5 μg/g-50 μg/g, reducing the content of sulfide introduced into the system when hydrogen sulfide concentration in the recycle gas reaches to 2.0 μL/L˜30 μL/L; and
  • (2) maintaining the reforming reactor at a temperature of 460-490° C., controlling the ratio of the total sulfur amount introduced into the system to the reforming feedstock within the range of 0.2 μg/g-0.5 μg/g, adjusting the amount of the reforming feedstock to the design value of the apparatus, increasing the reforming reaction temperature to 490-545° C. according to the requirements on the octane number of the liquid product, and letting the reforming apparatus run under normal operating conditions.

A method and apparatus to extract and sequester carbon dioxide (CO₂) from a stream or volume of gas wherein said method and apparatus hydrates CO₂, and reacts the resulting carbonic acid with carbonate. Suitable carbonates include, but are not limited to, carbonates of alkali metals and alkaline earth metals, preferably carbonates of calcium and magnesium. Waste products are metal cations and bicarbonate in solution or dehydrated metal salts, which when disposed of in a large body of water provide an effective way of sequestering CO₂ from a gaseous environment.

Methods of sequestering carbon dioxide (CO₂) are provided. Aspects of the methods include precipitating a storage stable carbon dioxide sequestering product from an alkaline-earth-metal-containing water and then disposing of the product, e.g., by placing the product in a disposal location or using the product as a component of a manufactured composition. Also provided are systems for practicing methods of the invention.

A process for selectively removing carbon dioxide from a gaseous stream by converting the carbon dioxide to a solid, stable form is provided. In a sequestration process, carbon dioxide enriched air is passed through a gas diffusion membrane to transfer the carbon dioxide to a fluid medium. The carbon dioxide rich fluid is then passed through a matrix containing a catalyst specific for carbon dioxide, which accelerates the conversion of the carbon dioxide to carbonic acid. In the final step, a mineral ion is added to the reaction so that a precipitate of carbonate salt is formed. This solid mineral precipitate can be safely stored for extended periods of time, such as by burying the precipitate in the ground or depositing the precipitate into storage sites either on land or into a body of water. An apparatus for removing carbon dioxide from a gaseous stream is also provided.

The present invention is directed to methods for removing carbon dioxide from air, which comprises exposing solvent covered surfaces to air streams where the airflow is kept laminar, or close to the laminar regime. The invention also provides for an apparatus, which is a laminar scrubber, comprising solvent covered surfaces situated such that they can be exposed to air stream. In another aspect, the invention provides a method and apparatus for separating carbon dioxide (CO₂) bound in a solvent. The invention is particularly useful in processing hydroxide solvents containing CO₂ captured from air.

New low-cost CO₂ sorbents are provided that can be used in large-scale gas-solid processes. A new method is provided for making these sorbents that involves treating substrates with an amine and/or an ether so that the amine and/or ether comprise at least 50 wt. percent of the sorbent. The sorbent acts by capturing compounds contained in gaseous fluids via chemisorption and/or physisorption between the unit layers of the substrate's lattice where the polar amine liquids and solids and/or polar ether liquids and solids are located. The method eliminates the need for high surface area supports and polymeric materials for the preparation of CO₂ capture systems, and provides sorbents with absorption capabilities that are independent of the sorbents' surface areas. The sorbents can be regenerated by heating at temperatures in excess of 35° C.

A process for recovering CO₂ from a feed gas stream comprises treating the feed gas stream with a regenerated absorbent comprising at least one tertiary amine absorbent having a pK_a for the amino function of from about 6.5 to about 9 in the presence of an oxidation inhibitor to obtain a CO₂ rich stream and subsequently treating the CO₂ rich stream to obtain the regenerated absorbent and a CO₂ rich product stream. The feed gas stream may also include SO₂ and/or NO_x.

Particulate compositions are described comprising a carbonaceous material, such as petroleum coke and/or coal, treated or otherwise associated with a gasification catalyst, where the catalyst is at least in part derived from a leachate from a biomass char, for gasification in the presence of steam to yield a plurality of gases including methane and at least one or more of hydrogen, carbon monoxide, and other higher hydrocarbons are formed. Processes are also provided for the preparation of the particulate compositions and converting the particulate composition into a plurality of gaseous products.

Apparatuses and methods for removing carbon dioxide and other pollutants from a gas stream are provided. The methods include obtaining hydroxide in an aqueous mixture, and mixing the hydroxide with the gas stream to produce carbonate and/or bicarbonate. Some of the apparatuses of the present invention comprise an electrolysis chamber for providing hydroxide and mixing equipment for mixing the hydroxide with a gas stream including carbon dioxide to form an admixture including carbonate and/or bicarbonate.

A method of sequestering a greenhouse gas is described, which comprises: (i) providing a solution carrying a first reagent that is capable of reacting with a greenhouse gas; (ii) contacting the solution with a greenhouse gas under conditions that promote a reaction between the at least first reagent and the greenhouse gas to produce at least a first reactant; (iii) providing a porous matrix having interstitial spaces and comprising at least a second reactant; (iv) allowing a solution carrying the at least first reactant to infiltrate at least a substantial portion of the interstitial spaces of the porous matrix under conditions that promote a reaction between the at least first reactant and the at least second reactant to provide at least a first product; and (v) allowing the at least first product to form and fill at least a portion of the interior spaces of the porous matrix, thereby sequestering a greenhouse gas.

Processes are provided for capturing and recycling carbonaceous fines generated during a gasification process. In particular, the recycled fines are processed into a particulate composition which is useable as a carbonaceous feedstock and is conversion into a gas stream comprising methane.

A system involving a two-step gasification of a carbonaceous source to produce bulk hydrogen that avoids the early formation of CO₂ and obviates the traditional water gas shift (WGSR) step, carbochlorination of a metallic ore the production of metals found in the ore that utilizes carbon monoxide as an oxygen sink, rather than the traditional coke, and carbon oxides management that eliminates major impediments to emission-neutral power generation and the reduction of major metals. The gasification uses a rotary kiln reactor and gas-gas cyclonic separation process to separate synthesis gas into purified hydrogen and purified carbon monoxide. Purified bulk carbon monoxide issued in metallurgical reduction, and purified bulk hydrogen as fuel for an emission-neutral hydrogen combined cycle (HCC) turbine power generation station. The carbochlorination is integrated with: a) the concurrent separation and purification of all metal-chlorides (metchlors) and capture of CO₂ for passage to the carbon oxides management system; b) the direct reduction of metchlors to nanoscale metallurgical powders and/or to dendritically-shaped particles, including metchlor reduction for the ultrahigh-performance semiconductor metals of the III-V group; and, c) the reforming of metal-oxides with improved crystalline structure from metchlors. The carbon oxides management collects, stores and directs to points of usage, carbon oxides that arise in various processes of the integrated system, and captures carbon monoxide for process enhancement and economic uses and captures carbon dioxide as a process intermediate and for economic uses.

A new method for the removal of environmental compounds from gaseous streams, in particular, flue gas streams. The new method involves first oxidizing some or all of the acid anhydrides contained in the gas stream such as sulfur dioxide (SO₂) and nitric oxide (NO) and nitrous oxide (N₂O) to sulfur trioxide (SO₃) and nitrogen dioxide (NO₂). The gas stream is subsequently treated with aqua ammonia or ammonium hydroxide which captures the compounds via chemical absorption through acid-base or neutralization reactions. The products of the reactions can be collected as slurries, dewatered, and dried for use as fertilizers, or once the slurries have been dewatered, used directly as fertilizers. The ammonium hydroxide can be regenerated and recycled for use via thermal decomposition of ammonium bicarbonate, one of the products formed. There are alternative embodiments which entail stoichiometric scrubbing of nitrogen oxides and sulfur oxides with subsequent separate scrubbing of carbon dioxide.

A process and method for separating CO₂ from a gaseous stream such as natural gas. An ionic liquid comprising an anion having a carboxylate function is used as an adsorbent to selectively complex the CO₂ yielding a gaseous stream with a greatly reduced CO₂ content. The ionic liquid can then be readily be regenerated and recycled.

The present invention provides a method and apparatus for removing a contaminant, such as carbon dioxide, from a gas stream, such as ambient air. The contaminant is removed from the gas stream by a sorbent which may be regenerated using a humidity swing, a thermal swing, or a combination thereof. The sorbent may comprise a substrate having embedded positive ions and individually mobile negative ions wherein the positive ions are sufficiently spaced to prevent interactions between the negative ions. Where a thermal swing is used, heat may be conserved by employing a heat exchanger to transfer heat from the regenerated sorbent to an amount of sorbent that is loaded with the contaminant prior to regeneration.

An acid gas removal plant includes an absorber that provides a rich solvent to two regenerators that independently generate a lean and a semi-lean solvent, wherein the semi-lean solvent is produced in one of the regenerators using heat and/or steam derived from the other regenerator. Further heat integration is particularly contemplated with power plants in which the power plant provides high-level heat to the acid gas removal plant and wherein the power plant receives low-level heat from the acid gas removal plant.

There is provided a process for the capture and sequestration of carbon dioxide that would otherwise enter the atmosphere and contribute to global warming and other problems. CO₂ capture is accomplished by reacting carbon dioxide in flue gas with an alkali metal carbonate, or a metal oxide, particularly containing an alkaline earth metal or iron, to form a carbonate salt. A preferred carbonate for CO₂ capture is a dilute aqueous solution of additive-free (Na₂CO₃). Other carbonates include (K₂CO₃) or other metal ion that can produce both a carbonate and a bicarbonate salt. Examples of suitable metal oxides include several alkaline earths including CaO and MgO. The captured CO₂ is preferably sequestered using any available mineral or industrial waste that contains calcium magnesium or iron in non-carbonate forms, or iron in the Fe⁺² oxidation state.

The gaseous effluent flowing in through line 1 is contacted in absorption zone ZA with the liquid absorbent solution flowing in through line 9. The gaseous effluent depleted in acid compounds is discharged through line 2. The absorbent solution laden with acid compounds is discharged through line 3. The absorbent solution once laden with acid compounds comprises two phases: a first phase poor in acid compounds and a second phase rich in acid compounds. The two phases are separated in zone ZS. The first phase is recycled through lines 5 and 9 to absorption zone ZA. The second phase is fed through line 4 into regeneration zone ZR. In zone ZR, the acid compounds are separated from the absorbent solution. The acid compounds are discharged through line 7. The regenerated absorbent solution is recycled through lines 6 and 9 to zone ZA.

A steam methane reforming method in which a feed stream is treated in a reactor containing a catalyst that is capable of promoting both hydrogenation and partial oxidation reactions. The reactor is either operated in a catalytic hydrogenation mode to convert olefins into saturated hydrocarbons and/or to chemically reduce sulfur species to hydrogen sulfide or a catalytic oxidative mode utilizing oxygen and steam to prereform the feed and thus, increase the hydrogen content of a synthesis gas produced by a steam methane reformer. The method is applicable to the treatment of feed streams containing at least 15% by volume of hydrocarbons with two or more carbon atoms and/or 3% by volume of olefins, such as a refinery off-gas. In such case, the catalytic oxidative mode is conducted with a steam to carbon ratio of less than 0.5, an oxygen to carbon ratio of less than 0.25 and a reaction temperature of between about 500° C. and about 860° C. to limit the feed to the steam methane reformer to volumetric dry concentrations of less than about 0.5% for the olefins and less than about 10% for alkanes with two or more carbon atoms.

The present invention generally relates to a process for the formation of a CO₂-selective absorption material and/or sulfur-selective absorption material. In one embodiment, the present invention relates to a process for the formation of a CO₂-selective absorption material that comprises providing a solid material, providing an amine source, contacting the solid material with the amine source to absorb amine molecules on the surface of the solid material, and contacting the absorbing amine molecules on the solid material surface with a CO₂ stream such that upon contact with the amine and the solid material, CO₂ binds with the amine functional group of the amine molecule, reducing the potential for the interaction of the amine functional group with the solid surface and increasing amine sites available for CO₂ capture.

A method of deacidizing a gaseous effluent comprising acid compounds where the gaseous effluent is contacted in C1 with an adsorbent solution so as to obtain a gaseous effluent depleted in acid compounds and an absorbent solution laden with acid compounds, the absorbent solution being selected for its property of forming two separable phases when it has absorbed an amount of acid compounds and when it is heated. The absorbent solution laden with acid compounds is then heated in E1 and E3 so as to separate two fractions: a first absorbent solution fraction depleted in acid compounds and a second absorbent solution fraction enriched in acid compounds. These two fractions are then separated in BS1. The second fraction is regenerated in C2 so as to release part of the acid compounds, and the first absorbent solution fraction and the regenerated absorbent solution are recycled as absorbent solution.

A method is provided for making low-cost CO₂ sorbents that can be used in large-scale gas-solid processes. The improved method entails treating an amine to increase the number of secondary amine groups and impregnating the amine in a porous solid support. The method increases the CO₂ capture capacity and decreases the cost of utilizing an amine-enriched solid sorbent in CO₂ capture systems.