A porous carbon-based metal catalyst, a preparation method and application thereof are provided. The preparation method includes: successively performing activation, surface corrosion, nitrogen-doping treatment and graphitization treatment on washed micro-grade porous carbon, then performing sensitization treatment, and subsequently carrying out loading, reduction and other treatments of catalytic metal, so as to finally obtain the porous carbon-based metal catalyst. The porous carbon-based metal catalyst provided by the present application has excellent catalytic performance, is especially suitable for producing hydrogen by efficiently catalytically decomposing ammonia borane, is not prone to inactivation, and is easy to regenerate after inactivation. Meanwhile, the preparation method is environmental-friendly, is suitable for large-scale production and has a wide application prospect in the fields such as hydrogen fuel batteries.

The present invention provides methods for low temperature desulfating sulfur-poisoned SCR catalysts, and emission control systems adapted to apply such desulfating methods, in order to regenerate catalytic NOx conversion activity. The methods are adapted for treating an SCR catalyst to desorb sulfur from the surface of the SCR catalyst and increase NOx conversion activity of the SCR catalyst, the treating step including treating the SCR catalyst with a gaseous stream comprising a reductant for a first treatment time period and at a first treatment temperature, wherein the first treatment temperature is about 350° C. or less, followed by a second treatment time period and a second treatment temperature higher than the first treatment temperature, wherein the molar ratio of reductant to NOx during the treating step is about 1.05:1 or higher.

The present invention provides methods for low temperature desulfating sulfur-poisoned SCR catalysts, and emission control systems adapted to apply such desulfating methods, in order to regenerate catalytic NOx conversion activity. The methods are adapted for treating an SCR catalyst to desorb sulfur from the surface of the SCR catalyst and increase NOx conversion activity of the SCR catalyst, the treating step including treating the SCR catalyst with a gaseous stream comprising a reductant for a first treatment time period and at a first treatment temperature, wherein the first treatment temperature is about 350° C. or less, followed by a second treatment time period and a second treatment temperature higher than the first treatment temperature, wherein the molar ratio of reductant to NOx during the treating step is about 1.05:1 or higher.

Provided is a hydro-regeneration catalyst system, comprising: (a) a first graded bed comprising a guard bed material; and (b) a second graded bed, fluidly connected to the first graded bed, comprising a noble metal catalyst on a support having mesopores and macropores; wherein the noble metal catalyst has an average pore diameter of 20 to 1,000 nm (0.02 to 1 μm), a total pore volume of greater than 0.80 cc/g, and a macropore volume of 0.10 to 0.50 cc/g. Also provided is a guard bed system, comprising: (a) a first guard bed comprising a first adsorbent having 10 μm or larger pores with an average pore diameter of 100 to 1,000 μm; and (b) a second guard bed fluidly connected to the first guard bed, comprising a second adsorbent material having mesopores and macropores with a second average pore diameter of 20 to 1,000 nm.

Provided is a hydro-regeneration catalyst system, comprising: (a) a first graded bed comprising a guard bed material; and (b) a second graded bed, fluidly connected to the first graded bed, comprising a noble metal catalyst on a support having mesopores and macropores; wherein the noble metal catalyst has an average pore diameter of 20 to 1,000 nm (0.02 to 1 μm), a total pore volume of greater than 0.80 cc/g, and a macropore volume of 0.10 to 0.50 cc/g. Also provided is a guard bed system, comprising: (a) a first guard bed comprising a first adsorbent having 10 μm or larger pores with an average pore diameter of 100 to 1,000 μm; and (b) a second guard bed fluidly connected to the first guard bed, comprising a second adsorbent material having mesopores and macropores with a second average pore diameter of 20 to 1,000 nm.

Some embodiments of the present disclosure relate to a method of regenerating at least one filter medium comprising: providing at least one filter medium, wherein the at least one filter medium comprises: at least one catalyst material; and ammonium bisulfate (ABS) deposits, ammonium sulfate (AS) deposits, or any combination thereof; flowing a flue gas stream transverse to a cross-section of a filter medium, such that the flue gas stream passes through the cross section of the at least one filter medium, wherein the flue gas stream comprises: NO.sub.x compounds comprising: Nitric Oxide (NO), and Nitrogen Dioxide (NO.sub.2); and increasing an NO.sub.x removal efficiency of the at least one filter medium after removal of deposits.

Some embodiments of the present disclosure relate to a method of regenerating at least one filter medium comprising: providing at least one filter medium, wherein the at least one filter medium comprises: at least one catalyst material; and ammonium bisulfate (ABS) deposits, ammonium sulfate (AS) deposits, or any combination thereof; flowing a flue gas stream transverse to a cross-section of a filter medium, such that the flue gas stream passes through the cross section of the at least one filter medium, wherein the flue gas stream comprises: NO.sub.x compounds comprising: Nitric Oxide (NO), and Nitrogen Dioxide (NO.sub.2); and increasing an NO.sub.x removal efficiency of the at least one filter medium after removal of deposits.

A method of equipment decontamination may include: introducing a cleaning stream comprising hydrogen and a solvent comprising a fatty acid methyl ester and an oxygenated solvent, or alternatively comprising a carrier fluid and a hydrocarbon solvent, into the equipment; and introducing a stream comprising nitrogen into the equipment, wherein the equipment comprises deposits and other contaminants.

The invention provides a method of reducing the amount of nitrogen oxide components in a process gas stream comprising: a) contacting a deNO.sub.X catalyst with the process gas in the presence of ammonia which results in the conversion of nitrogen oxide components as well as a decline in the NO.sub.X conversion over the deNO.sub.X catalyst; and b) regenerating the deNO.sub.X catalyst to improve the NO.sub.X conversion by contacting the deNO.sub.X catalyst at a temperature in the range of from 250 to 390 C. with a flow of ammonia that is reduced relative to the flow of ammonia in step a) and process gas, air or a mixture thereof.

The invention provides a method of reducing the amount of nitrogen oxide components in a process gas stream comprising: a) contacting a deNO.sub.X catalyst with the process gas in the presence of ammonia which results in the conversion of nitrogen oxide components as well as a decline in the NO.sub.X conversion over the deNO.sub.X catalyst; and b) regenerating the deNO.sub.X catalyst to improve the NO.sub.X conversion by contacting the deNO.sub.X catalyst at a temperature in the range of from 250 to 390 C. with a flow of ammonia that is reduced relative to the flow of ammonia in step a) and process gas, air or a mixture thereof.