(111a) Process Configuration Studies of Conventional Pre- and Post-Combustion Carbon Capture for Power Plants

                                                                                                                  Process Configuration Studies of Conventional Pre- and Post-Combustion Carbon Capture for Power Plants

Hyungwoong Ahn, Zoe Kapetaki, Pietro Brandani, Mauro Luberti and Stefano Brandani*

Scottish Carbon Capture and Storage Centre (SCCS)

Institute for Materials and Processes, School of Engineering, University of Edinburgh

Mayfield Road, Edinburgh, EH9 3JL, UK

It is well known that an alkanolamine process and a Selexol process are conventional carbon capture processes for post-combustion at the pulverized-coal boiler power plant and for the pre-combustion at IGCC, respectively. The integration of those carbon capture processes into power plants entails considerable energy penalties in power generation.¹ However, the energy penalties resulting from pre- and post- combustion carbon capture can be reduced by a modification of process configuration of amine or Selexol process. A sub-critical PC-fired power plant and an IGCC plant based on a Shell gasifier have been simulated using Honeywell UniSim in order to identify the feed composition to capture units and come up with optimised heat integration of power plant and capture unit. Process simulation of ten different amine processes have been constructed using amine thermodynamic package to estimate the energy saving effect resulting from the improved process configuration².

The Selexol process is configured to have two solvent loops to capture H₂S and CO₂ simultaneously. Firstly, it is shown that its energy consumption can be lowered when the two capture loops are integrated rather than separated. It is also proposed that the dual-stage Selexol unit can be further improved by introducing a novel cryogenic capture process for CO₂ bulk separation integrated with a dual-stage Selexol unit for H₂S capture and finishing capture for CO₂ purification³.

[1] Cost and Performances Baseline for Fossil Energy Plants: Vol.1: Bituminous Coal and Natural Gas to Electricity Final Report, DOE/NETL-2007/1281, 2007.

[2] Ahn, H., Luberti, M., Liu, Z., and Brandani, S., Process Configuration Studies of the Amine Capture Process for Coal-fired Power Plants, Int. J. of Greenhouse Gas Control, Vol. 16, 29-40, 2013.

[3] Kapetaki, Z., Brandani, P., Ahn, H., and Brandani, S., Process Configuration Studies of a Novel Hybrid Cryogenic/Selexol Process Integrated with an IGCC Power Plant, preparing.