Evaluation of Gas Turbine and Gasifier-based Power Generation System

Abstract

As a technology in early commercial phase, research work is needed to provide evaluation of the effects of alternative designs and technology advances and provide guidelines for development direction of Integrated Gasification Combined Cycle (IGCC) technology in future. The objective of this study is to evaluate the potential pay-offs as well as risks of technological infeasibility for IGCC systems and to provide insight regarding desired strategies for the future development of advanced IGCC systems.

Texaco gasifier process is widely used in power generation. A process simulation model for a base Texaco gasifier-based IGCC system, including performance (e.g., efficiency), emissions, and cost, was implemented in the ASPEN Plus. To find out the implications of the effects of coal compositions on IGCC plant, Illinois No.6, Pittsburgh No.8, and West Kentucky coal are selected for comparison. The effects of the most advanced Frame 7H and the current widely used Frame 7F gas turbine combined cycles on IGCC system were evaluated. The IGCC system based on 7H gas turbine (IGCC-7H) has higher efficiency, lower CO2 emission, and lower cost of electricity than the 7FA based system (IGCC-7FA). A simplified spreadsheet model is developed to estimate performance of gas turbine combined cycle. This study implicated the ability to do desktop simulations to support policy analysis. Uncertainty analysis is implemented to evaluate risks associated with IGCC systems, i.e., there is about 80% probability that the uncertain results of the efficiency of IGCC-7FA are lower than the deterministic result. The IGCC-7H system is superior to IGCC-7FA despite the uncertainty of inputs. Gasifier carbon conversion and project uncertainty are identified as the key uncertain inputs. The effects of different integration methods of air separation unit (ASU) and gas turbine are evaluated. The results indicate that the integrated IGCC design has higher efficiency and lower cost than nonintegrated design.

Recommendations are provided based on the simulation and evaluation work, and main conclusions. More standard IGCC systems should be developed to provide a consistent basis for benchmarking, verification, and comparison.