The invention relates to a process for decomposing nitrous oxide from a gas stream (1). comprising: (a) heating the gas stream (1) and splitting the gas stream (1) into at least two partial streams (3, 5) or splitting the gas stream (1) into at least two partial streams (3, 5) and heating the partial streams (3, 5): (b) feeding each of the partial streams (3, 5) into a separate decomposition reactor, wherein each reactor (31) comprises a catalyst: (c) decomposing the nitrous oxide into nitrogen and oxygen in the decomposition reactors to obtain purified streams (13, 15): (d) optionally feeding each purified stream (13, 15) into a unit (11) for decomposing nitrogen dioxide and/or nitrogen monoxide or combining at least two purified streams (13, 15) and feeding the combined purified streams into a unit (11) for decomposing nitrogen dioxide and/or nitrogen monoxide, wherein the catalysts of the decomposition reactors (31) are changed alternatingly and wherein one of the catalysts is changed when the arithmetic mean of the lifetime of the catalysts in the other reactors has reached 25 to 75% of the lifetime of one catalyst.

The invention relates on a process for working-up a nitrous oxide comprising off-gas stream from a production process of adipic acid by decomposing the nitrous oxide contained in the off-gas stream into nitrogen and oxygen in a fixed bed reactor (21) of a N.sub.2O decomposition unit (9) at a temperature in the range from 430 to 800? C. to obtain a purified gas, wherein for controlling the N.sub.2O decomposition unit (9) a nonlinear model predictive control is used which is based on a reactor model of the fixed bed reactor based on equations of energy transport and species transport for nitrogen, oxygen and N.sub.2O.

Method and apparatus for preparation of fuel from biomass wherein the biomass is subjected to a heat treatment in a temperature range from 150 to 300 C, in a reactor pressurized with steam and air, wherein the pressure at completed treatment is released. The volume increase of steam and other gases from the pressure release is temporarily accumulated in a container of a flexible volume while steam and other gases are subjected to heat exchange in at least one heat exchanger so that condensable gases are condensed and release their heat of condensation in the at least one heat exchanger.

A method for the purification of a raw gas stream by selective catalytic oxidation, in which organic and inorganic sulfur compounds, halogenated and non-halogenated volatile organic compounds are selectively oxidized without substantially oxidizing the lower hydrocarbons and the sulfur containing compounds present in the gas to sulfur trioxide and excess of oxygen is removed by oxidation of lower alcohols, ethers or hydrogen added to the raw gas stream upstream the catalytic oxidation.

A vehicle exhaust system is provided and comprises a catalyst positioned in an exhaust passage of a vehicle. The catalyst is in the form of a washcoat supported on a substrate. The system includes a phase change material located adjacent to the catalyst to maintain the temperature of the catalyst between engine shut-down and subsequent start-up as well as to regulate the temperature during engine operation. In some embodiments, the phase change material comprises particles of a metal or metal alloy encapsulated in a ceramic material. The metal or metal alloy is adapted to have a phase change that occurs within a temperature range wherein the catalyst is active.

A method to recover sulfur from hydrogen sulfide in an acid gas stream comprising the steps of reacting the hydrogen sulfide and oxygen in the combustion furnace, transferring heat from the furnace effluent to produce a boiler effluent, reducing the temperature of the boiler effluent in the sulfur condenser, separating the water vapor from the non-condensed gases stream, reacting the sulfur dioxide and the hydrogen gas to produce hydrogen sulfide in the first hydrogenation reactor, reacting the hydrogen sulfide and oxygen in the reactor furnace to produce a reactor effluent, transferring heat from the reactor effluent to produce a cooled effluent, reducing the temperature of the cooled effluent in the sulfur cooler to produce a gases stream, separating the water vapor from the gases stream, reacting the sulfur dioxide and the hydrogen gas to produce hydrogen sulfide in the second hydrogenation reactor to produce a treated tail gas stream.

A multi-function duct for a dry scrubber system useful for processing a gas stream, such as a flue gas stream produced by a fossil fuel fired boiler, a combustion process or the like, is provided. The multi-function duct is useful for a circulating dry scrubber (CDS) dry flue gas desulfurization (DFGD) system operable for dry or moistened reducing agent distribution into a flue gas stream flowing therethrough. As such, the distributed dry or moistened reducing agent reacts with acid gas in the flue gas to produce a dry reaction product.

The present invention pertains to new methods for generating energy and useful nitrogen compounds from captured carbon dioxide. It involves employing an osmotic engine, draw solution, and feed solution. An osmotic gradient between the solutions assists in generating energy and a solution of ammonium carbonate, ammonium bicarbonate or mixture thereof. This solution may be decomposed to form ammonia, carbon dioxide, a precipitate, or a mixture thereof.

The disclosure relates to a hybrid gas treatment and energy recovery system. The system compresses, cools and scrubs the gasses all in one step. This hybrid gas treatment and energy recovery system may be used for exhaust gas scrubbing, odor control and direct air capture applications. Another unique aspect of this invention is the ability to be used as an energy storage system, using renewable energy to compress and clean gas, and then releasing the compressed gas through a gas turbine to recover the stored energy. The system may be implemented on land or at sea.

Methods of sequestering carbon dioxide (CO.sub.2) are provided. Aspects of the methods include contacting an aqueous capture ammonia with a gaseous source of CO.sub.2 under conditions sufficient to produce an aqueous ammonium carbonate. The aqueous ammonium carbonate is then combined with a cation source under conditions sufficient to produce a solid CO.sub.2 sequestering carbonate and an aqueous ammonium salt. The aqueous capture ammonia is then regenerated from the from the aqueous ammonium salt. Also provided are systems configured for carrying out the methods.