Config

 

Inputs for the configuration of the amine system in PC and NGCC plants are entered on the Config parameter screen. The following parameters are available:

•System Used: The type of absorber used. The following options are available:

•MEA: Monoethanolamine (MEA) is an amine which can be used to remove CO2 and H2S.

•FG+: (This is the default.) This process uses MEA along with an oxygen inhibitor to reduce sorbent degradation and equipment corrosion.

•Cansolv: The Shell Cansolv system is an amine-based CO2 capture system. It is used in the "NETL Case B12B" session in the session library. Note that this is not a generalized Cansolv model.

•Auxiliary Gas Boiler?: An auxiliary natural gas-fired boiler can be added to the amine system. When used, the original steam cycle of the power plant remains undisturbed and the net power generation capacity of the power plant is not adversely affected. The auxiliary boiler comes at an additional cost of capital requirement for the boiler (and turbine) and the cost of supplemental fuel. Also, the auxiliary boiler adds to the CO2 and NOx emissions. When an auxiliary boiler is added, an additional process type, Auxiliary Boiler System, is added; both parameters and results are provided. The following options are available:

•None: (This is the default.) An auxiliary gas boiler is not used.

•Steam Only: An auxiliary gas boiler is used to generate low pressure steam for sorbent regeneration.

•Steam + Power: An auxiliary gas boiler is used to generate low pressure steam for sorbent regeneration and separate power for the amine system.

•CO2 Product Compressor Used: The CO2 product stream may need to be compressed for transportation to a sequestration site. This parameter determines whether or not a CO2 product compressor is used. If a CO2 product compressor is used, the following parameter is also shown:

•Compressor Type: If a CO2 product compressor is used, this parameter determines whether it is a 6- or 8-stage compressor.

•Flue Gas Bypass Control: This popup selection menu controls whether or not a portion of the inlet flue gas may bypass the scrubber and recombine with the treated flue gas. Bypass allows the scrubber to operate at full efficiency while allowing some of the flue gas to go untreated. Two choices are available: No Bypass and Bypass. The no bypass option is the default and forces the entire flue gas to pass through the scrubber. The bypass option allows for the possibility of a portion of the flue gas to bypass the scrubber. The amount of bypass is controlled by several additional input parameters described below.

•Direct Contact Cooler (DCC) Used: A DCC is configured by default to cool the flue gas before it enters the amine system. The lower flue gas temperature enhances the absorption reaction (absorption of CO2 in MEA sorbent is an exothermic process) and decreases the flue gas volume. The typically acceptable range of flue gas temperature is about 120-140 degrees F. A DCC is often not needed if a wet FGD is installed upstream.

•SO2 Polisher Used: (PC plants only) This parameter determines whether or not an SO2 polisher is used to reduce the flue gas SO2 concentration. Standard wet FGD or sprayer units do not reduce the SO2 concentration sufficiently to the designated level for carbon capture pre-treatment. If an SO2 polisher is used, the following parameter is also displayed:

•SO2 Polisher Outlet Concentration: This is the SO2 concentration exiting the polisher, if one is in use. This value is used to determine the amount of reagent required. The default is based on the sorbent.

•Temperature Exiting DCC: (Only displayed when a DCC is used.) This is the temperature exiting the DCC. The desirable temperature of the flue gas entering the CO2 capture system is about 113-122 degrees F. If the inlet temperature to the DCC is at or below this temperature, the DCC is not used.

•Flue Gas Bypass: These parameters control the amount of bypass. They are only displayed if bypass is chosen above:

•Maximum CO2 Removal Efficiency: This parameter specifies the maximum efficiency possible for the absorber on an annual average basis. The value is used as a limit in calculating the actual CO2 removal efficiency for compliance.

•Overall CO2 Removal Efficiency: This is the CO2 removal efficiency required for the entire power plant to meet the CO2 emission constraint set earlier. It is used to determine the actual flue gas bypass above.

•Absorber CO2 Removal Efficiency: This is the actual removal efficiency of the absorber alone. It is a function of the CO2 emission constraint and the actual flue gas bypass.

•Minimum Bypass: This specifies the trigger point for allowing flue gas to bypass the scrubber. No bypass is allowed until the allowable amount reaches the minimum level set by this parameter.

•Allowable Bypass: This is the amount of flue gas that is allowed to bypass the scrubber, based on the actual and maximum performance of the CO2 removal. It is provided for reference only. The model determines the bypass that produces the maximum CO2 removal and compares this potential bypass with the minimum bypass value specified above. Bypass is only allowed when the potential bypass value exceeds the minimum bypass value.

•Actual Bypass: This is the actual bypass being used in the model. It is based on all of the above and is provided for reference purposes only.

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