CO2 Abatement Strategies for Polygeneration Systems: Process Integration and Analysis

Several decarbonised polygeneration systems exploiting carbon capture and storage (CCS) or CO2 reuse technologies for the conversion of primary resources into clean fuels, chemicals, electricity and heat are systematically analysed for techno-economic feasibility. A process simulation, energy integration and economic analysis based approach has been employed to arrive at a representative set of performance indicators for the trade-off analysis of polygeneration systems. These indicators include the effect of process configurations and operating conditions on the economic potential (EP), energy efficiency, decarbonisation potential, economic risks, value of products and sensitivity in EP due to carbon taxations. The systems under consideration include coal gasification systems with cogeneration and polygeneration, integrated with various CO2 abatement systems. Transforming a CCS based polygeneration Scheme A producing electricity, hydrogen, acetic acid and methanol, into an equivalent Scheme B additionally producing methane from the captured CO2 does not necessarily enhance efficiency, economic and emission performances. Upgrading cogeneration Scheme C into a polygeneration Scheme D additionally producing methanol clearly improves all performance indicators. While bio-oil based polygeneration system (Scheme E) creates environmental incentives, its economic competitiveness is uncertain and can be enhanced by introducing credits on product prices. Promising results in terms of improved energy efficiency from 36% in IGCC with CCS scheme to above 70% in 2 polygeneration schemes, viable EP and a minimum of 75% of plant-wide CO2 emission reduction demonstrate that the polygeneration Schemes A, D and E can become low carbon technologies of choice.