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Title: Improved system integration for integrated gasification combined cycle (IGCC) systems

Abstract

Integrated gasification combined cycle (IGCC) systems are a promising technology for power generation. They include an air separation unit (ASU), a gasification system, and a gas turbine combined cycle power block, and feature competitive efficiency and lower emissions compared to conventional power generation technology. IGCC systems are not yet in widespread commercial use and opportunities remain to improve system feasibility via improved process integration. A process simulation model was developed for IGCC systems with alternative types of ASU and gas turbine integration. The model is applied to evaluate integration schemes involving nitrogen injection, air extraction, and combinations of both, as well as different ASU pressure levels. The optimal nitrogen injection only case in combination with an elevated pressure ASU had the highest efficiency and power output and approximately the lowest emissions per unit output of all cases considered, and thus is a recommended design option. The optimal combination of air extraction coupled with nitrogen injection had slightly worse efficiency, power output, and emissions than the optimal nitrogen injection only case. Air extraction alone typically produced lower efficiency, lower power output, and higher emissions than all other cases. The recommended nitrogen injection only case is estimated to provide annualized cost savingsmore » compared to a nonintegrated design. Process simulation modeling is shown to be a useful tool for evaluation and screening of technology options. 27 refs., 3 figs., 4 tabs.« less

Authors:
;  [1]
  1. North Carolina State University, Raleigh, NC (United States). Department of Civil, Construction, and Environmental Engineering
Publication Date:
OSTI Identifier:
20727733
Resource Type:
Journal Article
Resource Relation:
Journal Name: Environmental Science and Technology; Journal Volume: 40; Journal Issue: 5; Other Information: frey@eos.ncsu.edu
Country of Publication:
United States
Language:
English
Subject:
20 FOSSIL-FUELED POWER PLANTS; 01 COAL, LIGNITE, AND PEAT; COMBINED-CYCLE POWER PLANTS; COAL GASIFICATION; NITROGEN; INJECTION; POWER GENERATION; GAS TURBINES; DESIGN; PERFORMANCE; COMPUTERIZED SIMULATION; DEMONSTRATION PROGRAMS; MATHEMATICAL MODELS; AIR; SEPARATION EQUIPMENT; EFFICIENCY; TECHNOLOGY ASSESSMENT

Citation Formats

H. Christopher Frey, and Yunhua Zhu. Improved system integration for integrated gasification combined cycle (IGCC) systems. United States: N. p., 2006. Web. doi:10.1021/es0515598.
H. Christopher Frey, & Yunhua Zhu. Improved system integration for integrated gasification combined cycle (IGCC) systems. United States. doi:10.1021/es0515598.
H. Christopher Frey, and Yunhua Zhu. Wed . "Improved system integration for integrated gasification combined cycle (IGCC) systems". United States. doi:10.1021/es0515598.
@article{osti_20727733,
title = {Improved system integration for integrated gasification combined cycle (IGCC) systems},
author = {H. Christopher Frey and Yunhua Zhu},
abstractNote = {Integrated gasification combined cycle (IGCC) systems are a promising technology for power generation. They include an air separation unit (ASU), a gasification system, and a gas turbine combined cycle power block, and feature competitive efficiency and lower emissions compared to conventional power generation technology. IGCC systems are not yet in widespread commercial use and opportunities remain to improve system feasibility via improved process integration. A process simulation model was developed for IGCC systems with alternative types of ASU and gas turbine integration. The model is applied to evaluate integration schemes involving nitrogen injection, air extraction, and combinations of both, as well as different ASU pressure levels. The optimal nitrogen injection only case in combination with an elevated pressure ASU had the highest efficiency and power output and approximately the lowest emissions per unit output of all cases considered, and thus is a recommended design option. The optimal combination of air extraction coupled with nitrogen injection had slightly worse efficiency, power output, and emissions than the optimal nitrogen injection only case. Air extraction alone typically produced lower efficiency, lower power output, and higher emissions than all other cases. The recommended nitrogen injection only case is estimated to provide annualized cost savings compared to a nonintegrated design. Process simulation modeling is shown to be a useful tool for evaluation and screening of technology options. 27 refs., 3 figs., 4 tabs.},
doi = {10.1021/es0515598},
journal = {Environmental Science and Technology},
number = 5,
volume = 40,
place = {United States},
year = {Wed Mar 01 00:00:00 EST 2006},
month = {Wed Mar 01 00:00:00 EST 2006}
}
  • A revolutionary hydrothermal heat recovery steam generator (HRSG) is being developed to produce clean fuels for gas turbines from slurries and emulsions of opportunity fuels. Water can be above 80% by weight and solids below 20%, including coal fines, coal water fuels, biomass, composted municipal refuse, sewage sludge and bitumen/Orimulsion. The patented HRSG tubes use a commercial method of particle scrubbing to improve heat transfer and prevent corrosion and deposition on heat transfer surfaces. A continuous-flow pilot plant is planned to test the HRSG over a wide range of operating conditions, including the supercritical conditions of water, above 221 barmore » (3,205 psia) and 374 C (705 F). Bench scale data shows, that supercritical water gasification below 580 C (1,076 F) and low residence time without catalysts or an oxidizer can produce a char product that can contain carbon up to the amount of fixed carbon in the proximate analysis of the solids in the feed. This char can be burned with coal in an existing combustion system to provide the heat required for gasification. The new HRSG tubes can be retrofitted into existing power plant boilers for repowering of existing plants for improved performance and reduced costs. A special condensing turbine allows final low-temperature cleaning and maintains quality and combustibility of the fuel vapor for modern gas turbine in the new Vapor Transmission Cycle (VTC). Increased power output and efficiency can be provided for existing plants, while reducing fuel costs. A preliminary computer-based process simulation model has been prepared that includes material and energy balances that simulate commercial-scale operations of the VTC on sewage sludge and coal. Results predict over 40% HHV thermal efficiency to electric power from sewage sludge at more than 83% water by weight. The system appears to become autothermal (no supplemental fuel required) at about 35% fixed carbon in the feed. Thus, bituminous and lignite coal slurries could be gasified at less than 25% coal and more than 75% water. Preliminary life cycle cost analyses indicate that disposal fees for sewage sludge improve operating economics over fuel that must be purchased, the cost and schedule advantages of natural gas-fired combined cycle systems are preserved. Sensitivity analyses show that increasing capital costs by 50% can be offset by an increase in sewage sludge disposal fees of $10/metric ton.« less
  • This report documents cost models developed for selected integrated gasification combined cycle (IGCC) systems. The objective is to obtain a series of capital and operating cost models that can be integrated with an existing set of IGCC process performance models developed at the US Department of Energy Morgantown Energy Technology Center. These models are implemented in ASPEN, a Fortran-based process simulator. Under a separate task, a probabilistic modeling capability has been added to the ASPEN simulator, facilitating analysis of uncertainties in new process performance and cost (Diwekar and Rubin, 1989). One application of the cost models presented here is tomore » explicitly characterize uncertainties in capital and annual costs, supplanting the traditional approach of incorporating uncertainty via a contingency factor. The IGCC systems selected by DOE/METC for cost model development include the following: KRW gasifier with cold gas cleanup; KRW gasifier with hot gas cleanup; and Lurgi gasifier with hot gas cleanup. For each technology, the cost model includes both capital and annual costs. The capital cost models estimate the costs of each major plant section as a function of key performance and design parameters. A standard cost method based on the Electric Power Research Institute (EPRI) Technical Assessment Guide (1986) was adopted. The annual cost models are based on operating and maintenance labor requirements, maintenance material requirements, the costs of utilities and reagent consumption, and credits from byproduct sales. Uncertainties in cost parameters are identified for both capital and operating cost models. Appendices contain cost models for the above three IGCC systems, a number of operating trains subroutines, range checking subroutines, and financial subroutines. 88 refs., 69 figs., 21 tabs.« less
  • Over the past three decades, significant efforts have been made toward the development of cleaner and more efficient technology for power generation. Coal gasification technology received a big thrust with the concept of combined cycle power generation. The integration of coal gasification with combined cycle for power generation (IGCC) had the inherent characteristic of gas cleanup and waste minimization, which made this system environmentally preferable. Commercial-scale demonstration of a cool water plant and other studies have shown that the greenhouse gas and particulates emission from an IGCC plant is drastically lower than the recommended federal New Source Performance Standard levels.more » IGCC also offers a phased construction and repowering option, which allows multiple-fuel flexibility and the necessary economic viability. IGCC technology advances continue to improve efficiency and further reduce the emissions, making it the technology of the 21st century.« less