IECM 12.0 beta User Manual > Modules Included with the IECM > Pulverized Coal (PC) Plant > SET PARAMETERS > CO2 Capture, Transport & Storage > 1. Amine System >

Retrofit or Adjustment Factors

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See Retrofit or Adjustment Factor Inputs for an explanation of retrofit costs. The amine system in PC and NGCC plants has the following capital cost process areas:

•SO2 Polisher/Direct Contact Cooler (PC) or Direct Contact Cooler (NGCC): For PC plants, an SO2 polisher may be used to reduce the SO2 concentration to very low levels. For all plant types, a direct contact cooler is typically used in plant configurations that do not include a wet FGD. A direct contact cooler is a large vessel where the incoming hot flue gas is placed in contact with cooling water. The cost is a function of the gas flow rate and temperature of the flue gas.

•Flue Gas Blower: The flue gas enters the bottom of the absorber column and flows upward, countercurrent to the sorbent flow. Blowers are required to overcome the substantial pressure drop as it passes through a very tall absorber column. The cost is a function of the volumetric flow rate of the flue gas.

•CO2 Absorber Vessel: The capital cost of the absorber will go down with higher MEA concentration and higher CO2 loading level of the solvent, and lower CO2 content in the lean solvent. Therefore, a power law relationship based on flue gas flow rate is used. This is based on cost and flow rate data from Fluor Daniel, Inc. The cost assumes one absorber vessel per train. The cost is a function of the volumetric flow rate of the flue gas and the flue gas temperature.

•Heat Exchangers: The CO2-loaded sorbent must be heated in order to strip off CO2 and regenerate the sorbent. In addition, the regenerated sorbent must be cooled down before it can be recirculated back to the absorber column. Heat exchangers are used to accomplish these two tasks. This area is a function of the sorbent flow rate.

•Circulation Pumps: Circulation pumps are required to take the sorbent, introduced at atmospheric pressure, and lift it to the top of the absorber column. This area is a function of the sorbent flow rate.

•Sorbent Regenerator: The regenerator (or stripper) is a column where the weak intermediate compound (carbamate) is broken down by the application of heat. The result is the release of CO2 (in concentrated form) and return of the recovered sorbent back to the absorber. This process is accomplished by the application of heat using a heat exchanger and low-pressure steam. MEA requires substantial heat to dissociate the carbamate. Therefore, a flash separator is also required, where the CO2 is separated from the moisture and evaporated sorbent to produce a concentrated CO2 stream. This area is a function of the sorbent flow rate.

•Reboiler: The regenerator is connected to a reboiler, which is a heat exchanger that utilizes low pressure steam to heat the loaded sorbent. The reboiler is part of the sorbent regeneration cycle. The cost is a function of the sorbent and steam flow rates.

•Steam Extractor: Steam extractors are installed to take low pressure steam from the steam turbines in the power plant. The cost is a function of the steam flow rate.

•Sorbent Reclaimer: A portion of the sorbent stream is distilled in the reclaimer in order to avoid accumulation of heat stable salts in the sorbent stream. Caustic is added to recover some of the MEA in this vessel. The reclaimer cost is a function of the sorbent makeup flow rate.

•Sorbent Processing: The sorbent processing area primarily consists of a sorbent cooler, MEA storage tank, and a mixer. The regenerated sorbent is further cooled with the sorbent cooler and MEA added to make up for sorbent losses. This area is a function of the sorbent makeup flow rate.

•CO2 Drying and Compression Unit: The product CO2 must be separated from the water vapor (dried) and compressed to liquid form in order to transport it over long distances. The multi-stage compression unit with inter-stage cooling and drying yields a final CO2 product at the nominal pressure of 2000 psig. This area is a function of the CO2 flow rate.

•Auxiliary Gas Boiler: An auxiliary natural gas boiler is typically combined with a steam turbine to generate some additional power and/or low pressure steam. The cost is a function of the steam flow rate generated by the boiler. The boiler cost is lower if electricity is not being produced.

•Auxiliary Steam Turbine: The steam turbine is used in conjunction with the natural gas boiler to generate some additional power and/or low pressure steam. The cost is a function of the secondary power generated by the turbine.