ECS offers high performance NSCR (Non-Selective Catalytic Reduction) catalyst for the abatement of NOx, carbon monoxide, and hydrocarbons emissions from tail gas exhaust between 400-1400°F.
The catalyst for the NOx reduction application is a high surface area, precious metal catalyst deposited on ceramic honeycomb or pellet support. The catalyst consists of various layers of a Platinum/Palladium/Rhodium coating based on plant specifications and permits. The layers are organized in a specific order to provide low light-off and high temperature stability and the honeycomb structure allows for minimal pressure drop across the catalyst, usually less than 1 psig.
Catalyst Theory
The ECS NSCR catalyst for a De-NOx application is designed to operate with natural gas or its components, e.g., butane, propane, Hydrogen and LPG. When natural gas is introduced into the catalytic combustor, the natural gas will react with O2 and NOx to form N2, CO2 and H2O. NOx reduction is a non-selective catalytic reduction and it will occur only under oxygen deficient conditions. The first rate reaction will be between O2 and CH4 creating CO and H2O. Some CO2 will be created at the first rate reaction. The second rate reaction will be between free carbons, CO and NO/NO2. Therefore it is necessary to operate the reactor in a slightly fuel rich environment to create enough thermal inefficiency to create sufficient amounts of CO to react with the NO/NOx combination. The first reaction will be a conversion of NO2 to NO. This is a fairly quick reaction and it will occur under oxygen rich conditions. De-colorization will occur at this stage of the process. The complete reaction of the available oxygen needs to operate slightly above stoichiometric is necessary to accomplish the degree of necessary NOx redcution.
Chemical Reactions
De-colorization Reactions:
| CH4 | + | 4NO2 | → | CO2 | + | 2H2O | + | 4NO |
| H2 | + | NO2 | → | H2O | + | NO | ||
| C4H10 | + | 13NO2 | → | 4CO2 | + | 5H2O | + | 13NO |
Abatement Reactions:
| CH4 | + | O2 | → | CO2 | + | 2H2O | ||
| 2H2 | + | O2 | → | H2O | ||||
| 2C4H10 | + | 13O2 | → | 8CO2 | + | 10H2O | ||
| CH4 | + | 4NO | → | CO2 | + | 2H2O | + | 2N2 |
| C4H10 | + | 13NO | → | 4CO2 | + | 5H2O | + | 6 1/2N2 |
The NSCR catalyst can use several types of fuels for light off.
Fuel Types/Light-Off Temperatures:
- Methane 890°F
- LPG 660°F
- Purge Gas 400°F
- Hydrogen 390°F
Competitive Advantages:
- Low Light Off Temperatures
- Durable Ceramic Construction
- Long Life Cycles
- Minimal Pressure Drop