Systems and methods for separating a biogas or other gaseous material into its constituent parts, including solid methane and carbon dioxide, using liquid nitrogen in a processing chamber. The individual parts may be extracted from the processing chamber. Separation and extraction can be performed on a mobile processing plant.

Methods of controlling hydrogen sulfide concentration of a biogas occupying an anaerobic membrane bioreactor (AnMBR) containing a submerged membrane are disclosed herein. Methods of controlling dissolved sulfide concentration of a mixed liquor within the AnMBR are disclosed. The methods include directing wastewater containing sulfur and a chemical oxygen demand (COD) to an AnMBR, withdrawing at least a fraction of the biogas from the AnMBR, directing a pre-determined amount of the withdrawn biogas to a scrubber, directing a remainder of the withdrawn biogas to a gas distributor, and directing the scrubbed biogas to the AnMBR. Systems for treating wastewater having sulfur and COD are disclosed. The systems include an AnMBR, a scouring gas closed loop, a scrubber, and a control mechanism for directing biogas to the scrubber and to a gas distributor. Methods of retrofitting a system for treating wastewater having sulfur and COD are disclosed.

Disclosed is an absorbent containing an amine for absorption of an acid gas in a biogas, and a biogas purification system using the same.

The invention provides a process for producing a fermentable gas stream from a gas source that contains one or more constituent which may be harmful to the fermentation process. To produce the fermentable gas stream, the gas stream is passed through a specifically ordered series of removal modules. The removal modules remove and/or convert various constituents found in the gas stream which may have harmful effects on downstream removal modules and/or inhibitory effects on downstream gas fermenting microorganisms. At least a portion of the fermentable gas stream is preferably capable of being passed to a bioreactor, which contains gas fermenting microorganisms, without inhibiting the fermentation process.

The present disclosure generally relates to a method for treatment of a lignocellulosic biomass. The method comprises the steps of pretreating the lignocellulosic biomass material in a pretreatment arrangement to form a pretreated biomass slurry; optionally hydrolysing the pretreated biomass slurry in a hydrolysis unit; retrieving gaseous SO2 from the pretreatment arrangement to provide an SO2 gas stream; treating the SO2 gas stream with an alkaline solution to provide a sulfite/bisulfite solution; supplying at least a part of the sulfite/bisulfite solution to at least one of: a) the lignocellulosic biomass material prior to pretreating the lignocellulosic biomass material in the pretreatment arrangement; b) the lignocellulosic biomass material n the pretreatment arrangement; c) the pretreated biomass slurry discharged from the reactor vessel; d) the hydrolysate or fermentable sugars of the hydrolysate.

There is disclosed a modular anaerobic digestion point-of-waste to renewable energy system. The system is directed to a modular and scalable anaerobic digestion system for point-of-waste use. The System includes a pretreatment process for removing inhibitory nutrients from a feedstock, an in-treatment process for providing clean renewable energy and a post-treatment process for further providing clean renewable energy for subsequent use. The System includes a leaching bed; a liquids tank; a mixing tank; an anaerobic digester reactor; a precipitation tank; a stripping tank; a hydrogen sulfide scrubber; a water remover; a gas bladder; a dewaterer; and a flare system.

The invention relates to a method for the biological in-situ methanation of CO.sub.2 and H.sub.2 in a bioreactor. The method includes feeding an organic substrate into the bioreactor wherein at least part of the organic substrate is converted to a biogas comprising methane and carbon dioxide by means of microorganisms. The organic substrate includes crude fiber and at least 0.15 kg of crude fiber per m.sup.3 bioreactor volume per day is fed into to the bioreactor. The bioreactor is operated at between about 20-45° C. H.sub.2 is fed to the CO.sub.2 into the bioreactor to produce methane.

A system for producing an organic substance, including: a synthesis gas generation furnace for producing a synthesis gas by partially oxidizing a waste including a carbon source; a synthesis gas purification unit connected to the synthesis gas generation furnace and purifying the synthesis gas generated in the synthesis gas generation furnace to reduce an impurity concentration in the synthesis gas; and an organic substance synthesis unit which is connected to the synthesis gas purification unit and generates an organic substance from the synthesis gas purified in the synthesis gas purification unit, wherein the synthesis gas purification unit includes a detection unit for measuring an impurity concentration in the synthesis gas.

A process and/or system for producing one or more biofuels, wherein biogas (e.g., partially purified biogas produced by removing water, hydrogen sulfide and/or carbon dioxide from raw biogas) is transported by vehicle in one or mobile vessels. De-pressurization of the mobile vessels provides a change in pressure that can be used to provide work, cooling, and/or increased pressure for the production process. Combustion of the biogas produces heat and/or power used to reduce a carbon intensity of the biofuel or biofuel intermediate.

The invention discloses a device for producing biogas with high methane content by utilizing livestock and poultry feces, wherein the interior of a tank body of a biogas fermentation tank is divided by a baffle, so as to form a main reaction chamber and an auxiliary reaction chamber which are communicated in upper portions, so that a reactant flows into the auxiliary reaction chamber only after entering the main reaction chamber via a relatively low feeding hole and then reaching a high position of a liquid level, and extension of fermentation time is realized, meanwhile, scales formed at the top of fermentation broth flow into the auxiliary reaction chamber along with liquid, so that the interior of the main reaction chamber keeps a liquid state all the time, and sealing and reduction of quantity of anaerobic bacteria are avoided.