Cost details from front-end engineering design of piperazine with the advanced stripper

Abstract

This Front-End Engineering Design (FEED) was funded by the U.S. Department of Energy (DOE) to estimate the cost to capture and compress 90 % of the CO2 from an existing natural gas combined cycle (NGCC) in Denver City, Texas, USA. The FEED used the PZAS (Piperazine with the Advanced Stripper) 2 G amine scrubbing technology developed and modeled by The University of Texas at Austin. This FEED is unique in providing more public cost details than other FEEDs funded by DOE. The primary objective of the FEED was to provide a comprehensive estimate for the total installed cost of the capture plant. The estimated capital cost of NGCC at the Mustang Station is $727 million for a capacity of 460 MW and 1.6 million tonnes CO2/yr. This includes a contingency of $104.6 million and a contractor's profit of $60.1 million. The total direct field cost is $384.1 million. With an optimistic fuel value of $3/MMBtu, the estimated cost of capture varies from $85/t at 4 % IRR/85 % load to $170/t at 10 % IRR/52 % load. Air cooling is technically feasible but expensive. The air cooling systems for the water wash and pump-around intercooling account for 23.4 % of the direct cost. The gas-fired boilers represent only 4 % of the direct costs, but steam extraction would reduce energy cost, free up cooling water, and reduce the direct costs of processing additional flue gas and CO2 from the boilers. The absorbers represent 9.6 % of the direct cost in this FEED with no direct contact cooler and only 7.6 m of packing. The solvent cross exchangers are less expensive than expected (2.5 % of direct costs). Doubling the number of these exchangers could reduce the heat duty from 3.0 to 2.5 GJ/t CO2.