The removal of acid gases (e.g., non-carbon dioxide acid gases) using sorbents that include salts in molten form, and related systems and methods, are generally described.

A system for removing undesirable compounds from contaminated air includes a biofilter having an alkaline material introduction system and a fuzzy-logic based controller. A contaminant, such as hydrogen sulfide, is removed from contaminated air by passing the contaminated air through the biofilter.

A system for removing undesirable compounds from contaminated air includes a biofilter having an alkaline material introduction system and a fuzzy-logic based controller. A contaminant, such as hydrogen sulfide, is removed from contaminated air by passing the contaminated air through the biofilter.

Scavenging chemicals used in mitigation treatments of hydrogen sulfide in hydrocarbon streams often continue to react and form polymers that foul the processing system. Disclosed herein are methods for determining if a scavenging chemical mitigator, or its reaction or degradation product, will polymerized during or after mitigation treatments. This information allows for the optimization of mitigation treatments that pre-emptively control or prevent polymer formation. Such pre-emption measures reduce the cost and time related to remedial actions to treat polymer-fouled equipment.

A chemical process captures and convert hydrogen sulfide (H.sub.2S) gas into elemental sulfur, polysulfide, sulfur dioxide and/or sulfuric acid while regenerating sodium hydroxide capture agent for further use in an initial H.sub.2S capture step. Processing may include initial sodium hydroxide scrubbing of gas streams containing H.sub.2S, electrochemical regeneration of the sodium hydroxide from sodium hydrosulfide or sodium sulfide, recovery of sulfur and/or sulfur dioxide from the electrochemical processing, and production of sulfuric acid from such sulfur and/or sulfur dioxide.

A chemical process captures and convert hydrogen sulfide (H.sub.2S) gas into elemental sulfur, polysulfide, sulfur dioxide and/or sulfuric acid while regenerating sodium hydroxide capture agent for further use in an initial H.sub.2S capture step. Processing may include initial sodium hydroxide scrubbing of gas streams containing H.sub.2S, electrochemical regeneration of the sodium hydroxide from sodium hydrosulfide or sodium sulfide, recovery of sulfur and/or sulfur dioxide from the electrochemical processing, and production of sulfuric acid from such sulfur and/or sulfur dioxide.

The system is provided with: a first heat exchanger which is interposed at an intersection between a rich solution supply line and a lean solution supply line, which has absorbed CO.sub.2 and H.sub.2S extracted from a bottom portion of an absorber, and a regenerated absorbent; a second heat exchanger which is interposed at an intersection between a semi-rich solution supply line and a branch line branched at the branch portion C from the lean solution supply line, and the lean solution; a merging portion which merges a branch line configured to supply the lean solution after heat exchange with the lean solution supply line; and a flow rate adjusting valve which is interposed in the lean solution supply line to adjust the distribution amount of the lean solution.

Compositions with supramolecular structures for use in oil and gas production and other applications include an H.sub.2S scavenger, a supramolecular host chemical or a supramolecular guest chemical configured to engage in host-guest chemistry with the scavenger, and a solvent. Methods of controlling H.sub.2S at a production site include applying an effective amount of the composition to the production stream.

Compositions with supramolecular structures for use in oil and gas production and other applications include an H.sub.2S scavenger, a supramolecular host chemical or a supramolecular guest chemical configured to engage in host-guest chemistry with the scavenger, and a solvent. Methods of controlling H.sub.2S at a production site include applying an effective amount of the composition to the production stream.

Systems and methods are provided for performing hydrodeoxygenation of bio-derived feeds while maintaining the hydrodeoxygenation catalyst in a sulfided state. During hydrodeoxygenation, a hydrogen-containing stream is provided to the hydrodeoxygenation reactor as a hydrogen treat gas to provide hydrogen for the reaction. In some aspects, the hydrogen treat gas used for hydrodeoxygenation can be formed at least in part from hydrogen that has been used as a stripping gas for removing H.sub.2S from a rich amine stream. In other aspects, H.sub.2S can be stripped using water vapor, and a resulting overhead HS stream can be compressed prior to incorporation of the H.sub.2S into a hydrogen-containing stream. The resulting hydrogen-containing stream can include sufficient H.sub.2S to substantially maintain the catalyst in the hydrodeoxygenation stage in a sulfided state.