摘要:
A method for oxidizing an amount of CO in a CO-containing gas stream, e.g., a combustion stream from fuel combustion, is provided. The method comprises exposing the CO-containing gas stream to a catalytic coating at reaction conditions, including at least 8 vol. % O2 and a temperature of at least 600° C. At these reaction conditions, the method comprises generating gaseous intermediate oxidizing species at the catalytic coating for oxidation of the carbon monoxide within the CO-containing gas stream as a homogeneous reaction to improve CO removal efficiency.
摘要:
A process and system (18) for reducing NOx in a gas using hydrogen as a reducing agent is provided. The process comprises contacting the gas stream (29) with a catalyst system (38) comprising sulfated zirconia washcoat particles (41), palladium, a pre-sulfated zirconia binder (44), and a promoter (45) comprising at least one of titanium, zinc, or a mixture thereof. The presence of zinc or titanium increases the resistance of the catalyst system to a sulfur and water-containing gas stream.
摘要:
A method for oxidizing an amount of CO in a CO-containing gas stream, e.g., a combustion stream from fuel combustion, is provided. The method comprises exposing the CO-containing gas stream to a catalytic coating at reaction conditions, including least 8 vol. % and a temperature of at least 600° C. At these reaction conditions, the method comprises generating gaseous intermediate oxidizing species at the catalytic coating for oxidation of the carbon monoxide within the CO-containing gas stream as a homogeneous reaction to improve CO removal efficiency.
摘要:
A process for producing a stable high-temperature catalyst for reduction of nitrogen oxides in combustion exhaust gases at operating temperatures from 300° C. to over 700° C. without the need for exhaust dilution. A zeolite material is steam-treated at a temperature and duration sufficient to partially de-aluminize the zeolite to approximately a steady state, but not sufficient to fully collapse its chemical structure. Iron is added to the zeolite material. The zeolite material is calcined at a temperature, humidity, and duration sufficient to stabilize the zeolite material. Examples and specifications for ranges, order, and durations of steaming, calcining, and other steps are provided.
摘要:
A process for producing a stable high-temperature catalyst for reduction of nitrogen oxides in combustion exhaust gases at operating temperatures from 300° C. to over 700° C. without the need for exhaust dilution. A zeolite material is steam-treated at a temperature and duration sufficient to partially de-aluminize the zeolite to approximately a steady state, but not sufficient to fully collapse its chemical structure. Iron is added to the zeolite material. The zeolite material is calcined at a temperature, humidity, and duration sufficient to stabilize the zeolite material. Examples and specifications for ranges, order, and durations of steaming, calcining, and other steps are provided.
摘要:
Improved processes for activating a catalyst system used for the reduction of nitrogen oxides are provided. In one embodiment, the catalyst system is activated by passing an activation gas stream having an amount of each of oxygen, water vapor, nitrogen oxides, and hydrogen over the catalyst system and increasing a temperature of the catalyst system to a temperature of at least 180° C. at a heating rate of from 1-20°/min. Use of activation processes described herein leads to a catalyst system with superior NOx reduction capabilities.
摘要:
A process and system (18) for reducing NOx in a gas using hydrogen as a reducing agent is provided. The process comprises contacting the gas stream (29) with a catalyst system (38) comprising sulfated zirconia washcoat particles (41), palladium, a pre-sulfated zirconia binder (44), and a promoter (45) comprising at least one of titanium, zinc, or a mixture thereof. The presence of zinc or titanium increases the resistance of the catalyst system to a sulfur and water-containing gas stream.
摘要:
A process for the catalytic reduction of nitrogen oxides (NOx) in a gas stream (29) in the presence of H2 is provided. The process comprises contacting the gas stream with a catalyst system (38) comprising zirconia-silica washcoat particles (41), a pre-sulfated zirconia binder (44), and a catalyst combination (40) comprising palladium and at least one of rhodium, ruthenium, or a mixture of ruthenium and rhodium.
摘要:
Improved processes for activating a catalyst system used for the reduction of nitrogen oxides are provided. In one embodiment, the catalyst system is activated by passing an activation gas stream having an amount of each of oxygen, water vapor, nitrogen oxides, and hydrogen over the catalyst system and increasing a temperature of the catalyst system to a temperature of at least 180° C. at a heating rate of from 1-20°/min. Use of activation processes described herein leads to a catalyst system with superior NOx reduction capabilities.
摘要:
A process for the catalytic reduction of nitrogen oxides (NOx) in a gas stream (29) in the presence of H2 is provided. The process comprises contacting the gas stream with a catalyst system (38) comprising zirconia-silica washcoat particles (41), a pre-sulfated zirconia binder (44), and a catalyst combination (40) comprising palladium and at least one of rhodium, ruthenium, or a mixture of ruthenium and rhodium.