Leigh Wardhaugh

Technical and Energy Performance of an Advanced, Aqueous Ammonia-Based CO2 Capture Technology for a 500 MW Coal-Fired Power Station.

Using a rate-based model, we assessed the technical feasibility and energy performance of an advanced aqueous-ammonia-based postcombustion capture process integrated with a coal-fired power station. The capture process consists of three identical process trains in parallel, each containing a CO2 capture unit, an NH3 recycling unit, a water separation unit, and a CO2 compressor. A sensitivity study of important parameters, such as NH3 concentration, lean CO2 loading, and stripper pressure, was performed to minimize the energy consumption involved in the CO2 capture process. Process modifications of the rich-split process and the interheating process were investigated to further reduce the solvent regeneration energy. The integrated capture system was then evaluated in terms of the mass balance and the energy consumption of each unit. The results show that our advanced ammonia process is technically feasible and energy-competitive, with a low net power-plant efficiency penalty of 7.7%.

Innovative Use of Membrane Contactor as Condenser for Heat Recovery in Carbon Capture

The gas-liquid membrane contactor generally used as a nonselective gas absorption enhancement device is innovatively proposed as a condenser for heat recovery in liquid-absorbent-based carbon capture. The membrane condenser is used as a heat exchanger to recover the latent heat of the exiting vapor from the desorber, and it can help achieve significant energy savings when proper membranes with high heat-transfer coefficients are used. Theoretical thermodynamic analysis of mass and heat transfer in the membrane condensation system shows that heat recovery increases dramatically as inlet gas temperature rises and outlet gas temperature falls. The optimal split mass flow rate is determined by the inlet gas temperature and the overall heat-transfer coefficient in the condensation system. The required membrane area is also strongly dependent on the overall heat-transfer coefficient, particularly at higher inlet gas temperatures. Mass transfer across the membrane has an insignificant effect on heat transfer and heat recovery, suggesting that membrane wetting may not be an issue when a membrane condenser is used for heat recovery. Our analysis provides important insights into the energy recovery performance of the membrane condensation system as well as selection of operational parameters, such as split mass flow rate and membrane area, thickness, and thermal conductivity.

Process Implications of CO2 Capture Solvent Selection

In the development of energy efficient solvents for advanced CO2 capture processes, it has often been the case that potentially excellent solvents are overlooked or set aside because of perceived process difficulties or extra costs due to the physical, chemical or thermodynamic properties of the solvent. This chapter considers the process implications of solvent selection with the objective of selecting and designing the process to suit the solvent rather than forcing the solvent into an existing process. The chapter discusses the design, modelling and costing of conventional amine processes insofar as advanced energy efficient solvents still rely on this process. Individual solvent properties, including reaction kinetics, thermodynamics and physical properties are outlined and their impact on design are discussed. Aspects such as degradation products, corrosivity and environmental considerations will impact the selection of process equipment and materials of construction. The impact of these properties of energy efficient solvents on individual unit operations are also discussed in some detail.

Results from Trialling Aqueous NH 3 Based Post Combustion Capture in a Pilot Plant at Munmorah Power Station: Desorption

Australia’s Commonwealth Scientific and Industrial Research Organization (CSIRO) and Delta Electricity have tested an aqueous ammonia based post combustion capture (PCC) process in a pilot plant at Munmorah black coal fired power station. This paper presents and discusses the experimental results obtained and primarily focuses on the desorption section.

26 – Pilot plant operation for liquid absorption-based post-combustion CO2 capture

Pilot-scale operation is often used when developing new technologies or processes for commercial application. It allows collation of realistic operating and engineering data at a smaller scale, and hence a smaller cost, than would be achieved at a full-size facility. Liquid absorbent-based removal of CO2 from process gas streams is not a new technology, having been used in applications such as natural gas processing. However, it has only recently been used to treat combustion flue gases. Research and commercial organizations worldwide have now constructed and operated pilot-scale post-combustion CO2 capture facilities operating on both synthetic and real combustion flue gases. This chapter considers the design and operation of these facilities, and also reviews the results achieved at several CO2 capture pilot plants.