A hydrogen feed stream comprising one or more impurities selected from the group consisting of nitrogen, argon, methane, carbon monoxide, carbon dioxide, oxygen, and water, is contacted with liquid hydrogen in a cryogenic wash column (CWC) process that produces pure hydrogen with high overall recovery. The waste liquid stream leaving the CWC may be used to improve the performance of upstream hydrogen processing steps.

The invention relates to a process and a plant for staged separation of concomitants from a raw synthesis gas stream to produce synthesis gas and a sulfur-free naphtha product as a by-product, To remove naphtha compounds and sulfur-containing concomitants, raw synthesis gas is treated with a scrubbing medium in a prescrubbing stage and withdrawn from the prescrubbing stage, and the laden scrubbing medium is mixed with water to bring about a phase separation into a scrubbing medium-water mixture and naphtha, wherein sulfur-containing concomitants are in solution in naphtha. To remove the sulfur-containing concomitants the naphtha is heated to obtain sulfur-free naphtha as a by-product of the gas scrubbing.

A method for recovering an acidic gas, includes: a step of bringing a gas to be treated that contains an acidic gas into gas-liquid into contact with an amine absorbing solution, allowing the amine absorbing solution to absorb the acidic gas, thereby removing the acidic gas from the gas to be treated; a step of allowing the amine absorbing solution that has absorbed the acidic gas to release the acidic gas, thereby regenerating the amine absorbing solution, and at the same time, recovering the released acidic gas; and an analysis step of calculating concentrations of iron ions and/or heavy metal ions in the amine absorbing solution.

A vertical bleaching tower for removing dissolved nitrogen oxides from an aqueous nitric acid solution using a stripping gas such as air, nitrogen, oxygen or combinations thereof in a process for producing nitric acid, comprising a structured packing; a liquid distributor comprising a feed box having a serrated weir for distribution of the aqueous nitric acid solution comprising the dissolved nitrogen oxides through upward-pointing serrations of the serrated weir into perforated trays of the liquid distributor and located above the structured packing for distributing the aqueous nitric acid solution comprising the dissolved nitrogen oxides to the structured packing; an inlet and outlet, both suitable for aqueous nitric acid solution; and an inlet and outlet, both suitable for the stripping gas. The present invention further comprises a bleaching method for removing dissolved nitrogen oxides from an aqueous nitric acid solution in a vertical bleaching tower

Systems and methods for preventing formation of carbonyl sulfide in the production of sweet gas using an amine-lean aqueous solution and metal oxide adsorbent material. In embodiments, a method may include producing, via an amine absorption column supplied with a raw gas stream that includes fractions of hydrogen sulfide (H.sub.2S), carbon dioxide (CO.sub.2), and carbon monoxide (CO), (1) a sweet gas stream that includes the fractions of the CO and (2) an amine-rich aqueous solution that includes the H.sub.2S and CO.sub.2. The method may include heating the amine-rich aqueous solution to produce a heated amine-rich aqueous solution. The method may include producing, via an amine regenerator supplied with the heated amine-rich aqueous solution (1) an acid gas stream that includes the H.sub.2S and CO.sub.2 and (2) an amine-lean aqueous solution. The method may include producing, via adsorption in a metal oxide adsorbent vessel, an effluent stream that includes the CO.sub.2.

The absorption agent of the present invention contains water, an amine compound, and an organic solvent, and a value obtained by subtracting a solubility parameter of the organic solvent from a solubility parameter of the amine compound is 1.1 (cal/cm.sup.3).sup.1/2 or more and 4.2 (cal/cm.sup.3).sup.1/2 or less. The method for separation and recovery of an acidic compound of the present invention includes the steps of: bringing a mixed gas containing an acidic compound into contact with an absorption agent containing water, an amine compound, and an organic solvent to absorb the acidic compound into the absorption agent; causing the absorption agent that has absorbed the acidic compound to be phase-separated into a first phase containing the acidic compound in a high content and a second phase containing the acidic compound in a low content; and heating the first phase to release the acidic compound from the first phase.

Systems and methods provide a self-contained sealed apparatus that captures, filters, compresses and stores methane gas produced by the decomposition of bio-degradable organic materials. The system includes a rotatable and sealable chamber with an intermittent drive unit that mixes moist bio-degradable material during an anaerobic reaction, and captures methane gas generated by anaerobic decomposition. A filter to remove impurities, a low-pressure storage tank, a compressor and a high-pressure storage tank are interconnected and controlled by a system that monitors system parameters, that may include gas flow rate, temperature, and gas volume, and controls system parameters, that may include drive unit activation, generator operation, and compressor operation.

Systems and methods for selectively removing hydrogen sulfide from a feed gas stream. The systems include an absorber-heat exchanger (ABHEX) assembly configured to exchange thermal energy between a mixed stream and a thermal management fluid stream. The ABHEX assembly defines a mixed stream volume and a thermal management fluid stream volume. The ABHEX assembly includes an isolation structure that maintains fluid separation between the mixed stream and the thermal management fluid stream and facilitates thermal communication between the mixed stream and the thermal management fluid stream. The ABHEX assembly is configured to receive and to mix the feed gas stream and a lean solvent stream to generate the mixed stream, to separate the mixed stream into a product gas stream and a rich solvent stream, and to cool the mixed stream. The methods include methods of operating the systems.

A process for recovering nitric acid or salts thereof, comprising: contacting, in the presence of water, an water-immiscible ionic liquid of the formula [A.sup.+][X.sup.−], wherein [A.sup.+] represents a phosphonium or ammonium cation and [X.sup.−] represents a counter anion which is NO.sub.3.sup.−, an halide anion displaceable by NO.sub.3.sup.−, or both, with a fluid which contains HNO.sub.3 and at least one more mineral acid, or precursors of said acids, and partition, under mixing, said acids between aqueous and organic phases and form nitrate-loaded ionic liquid of the formula [A.sup.+][NO.sub.3.sup.−].sub.z>0.25 where Z indicates a molar amount of nitrate held in the ionic liquid beyond the positions occupied by the nitrate counter ions; separating the so-formed mixture into an organic phase comprising a nitrate-loaded ionic liquid of the formula [A.sup.+][NO.sub.3.sup.−].sub.z>0.25 and an aqueous phase consisting of a nitrate-depleted aqueous solution that contains the other mineral acid(s); stripping the nitric acid from said nitrate-loaded ionic liquid to create an aqueous nitrate solution and regenerate ionic liquid of the formula [A.sup.+][NO.sub.3.sup.−].sub.z≥0 with reduced nitrate loading, or unloaded [A.sup.+][NO.sub.3.sup.−].sub.z=0 ionic liquid.

A plant and process for producing a hydrogen rich gas are provided, said process comprising the steps of: reforming a hydrocarbon feed in an autothermal reformer thereby obtaining a syngas; shifting said syngas in a shift configuration including a high temperature shift step; removal of CO.sub.2 in a CO.sub.2-removal section by amine wash thereby forming a hydrogen rich stream, a portion of which is used as low carbon hydrogen fuel, as well as a CO.sub.2-rich gas and a high-pressure flash gas stream. The high-pressure flash gas stream is advantageously integrated into the plant and process for further improving carbon capture.