Off-Design Performance of Power Plants: An Integrated Gasification Combined-Cycle Example

Abstract

Fossil-fueled power plants typically operate below their design capacities for a large fraction of their service life. In the United States, increased fuel and capital costs attributable to this off-design operation are considerable. This article describes the reasons for off-design operation and its importance in designing and selecting new power plants. Recent studies of coal gasification combined-cycle power plants show how computer simulations of off-design performance can aid in the design process, and they suggest that such simulations can be useful in reducing the cost of building and operating new power plants.

Integrated gasification combined cycle (IGCC) systems

“…Furthermore, for partial loads, one or more trains can be shut down, enabling the remaining trains to operate closer to their respective full load and at their most effi cient conditions. This feature of IGCC plants allows for more fl exible operation or shutdown strategies compared to conventional PC plants (Erbes et al ., 1987 ).…”

“…Thus, at low capacity only the fuel fl ow may be reduced, leading to reduction in the turbine inlet temperature. In turn, both the gas turbine and steam cycle effi ciencies will decrease (Erbes et al , 1987 ). The use of multiple gas turbines in parallel and supplemental fi ring methods upstream of the HRSG Published by Woodhead Publishing Limited, 2012 can maintain the exhaust temperature and the steam cycle power output and thus improve IGCC plant off-design performance (Erbes et al , 1987 ).…”

Integrated Gasification Combined Cycle— A Review of IGCC Technology

“…In the fourth and the final phase, a coal gasification plant is constructed and the entire facility is operated as a coal-fired IGCC power plant. Detailed engineering analyses are required to determine the performance of such schemes during each phase of operation (Erbes et al, 1987). (Erbes et al, 1987).…”

“…Detailed engineering analyses are required to determine the performance of such schemes during each phase of operation (Erbes et al, 1987). (Erbes et al, 1987). Shaded blocks represent new capacity; open blocks, existing capacity.…”

“…IGCC technology is modular in nature and offers the possibilities of phased construction. A schematic representation of one of many possible phasedconstruction scenarios for an IGCC plant is presented in Figure 15 (Erbes et al, 1987) The simple scheme in Figure 15 is based on two gas turbines. In the first phase, a single gas turbine is installed, to be fired by natural gas and using a peaking unit in a utility system.…”