IGCC System Research Articles

Research and Development of a New Coal Based Combined Cycle Power Plant Concept.

We propose a new coal-fired combined cycle power generation system featuring dust removal of high-temperature gas and wet desulfurization at the gas turbine outlet with the aim of improving the efficiency of the conventional IGCC system and reducing its construction cost. To study its feasibility, we conducted a fundamental study on the effects of alkali metal vapors in coal-derived gas on gas turbine blades and also studied remedial technology. The results of hot corrosion tests suggest that if the alkali metal vapor concentration in combustion gas is approximately 1 ppm or less current anticorrosion coating technology provides sufficient protection in practical use. The results of alkali removal tests show that 70% or higher removal rate can be achieved, which was considered a requirement for implementing the proposed system.

97/01397 New technology trends for improved IGCC system performance

97/01397 New technology trends for improved IGCC system performance

Water gas shift membrane reactor for CO2 control in IGCC systems: techno-economic feasibility study

A novel reactor concept, the water gas shift membrane reactor (WGS-MR) for CO2 removal in IGCC systems has been investigated. In order to establish full insight in the possibilities of the application of such a reactor, a multidisciplinary feasibility study has been carried out comprising system integration studies, catalyst research, membrane research, membrane reactor modelling and bench scale membrane reactor experiments. The application of the WGS-MR concept in IGCC systems is an attractive future option for CO2 removal as compared to conventional options. The net efficiency of the IGCC process with integrated WGS-MR is 42.8 % (LHV) with CO2 recovery (80 % based on coal input). This figure has to be compared with 46.7 % (LHV) of an IGCC without CO2 recovery and based on the same components, and with 40.5 % (LHV) of an IGCC with conventional CO2 removal. Moreover, an economic analysis indicates favourable investment and operational costs. The development of the process is considered to be technically feasible. However, it became clear that the technology of inorganic high selective gas separation membrane manufacturing and high temperature ceramic materials engineering is not yet mature and that further development in this area remains necessary.

Ammonia decomposition in coal gasification atmospheres

AbstractAmmonia present in the product gas from coal gasification may increase NOx emissions from IGCC systems. A fixed bed reactor was used to study the effect of calcined limestone (CaO) on NH3 decomposition and reaction of NH3 and NO. Reactions at temperatures to 900°C in helium and in gas compositions typical of air‐blown gasifiers were studied. Although CaO enhanced ammonia decomposition in helium, reaction in the gasification atmosphere resulted in the loss of this catalytic activity. Increasing the total pressure further reduced the rate of NH3 decomposition. CaO enhanced conversion of NO to NH3 in gasification atmospheres.

96/06633 Integrated approach to air pollution control in a simplified IGCC system

96/06633 Integrated approach to air pollution control in a simplified IGCC system

New Technology Trends for Improved IGCC System Performance

The application of gas turbine technology to IGCC systems requires careful consideration of the degree and type of integration used during the system design phase. Although gas turbines provide the primary output and efficiency gains for IGCC systems, as compared with conventional coal-fired power generation systems, they are commercially available only in specific size ranges. Therefore, it is up to the IGCC system designer to optimize the IGCC power plant within the required output, efficiency, and site conditions by selecting the system configuration carefully, particularly for air separation unit (ASU) integration incorporated with oxygen blown gasification systems. An IGCC system, based on a generic, entrained flow, oxygen blown gasification system and a GE STAG 109FA combined cycle has been evaluated with varying degrees of ASU integration, two fuel equivalent heating values and two gas turbine firing temperatures to provide net plant output and efficiency results. The data presented illustrate the system flexibility afforded by variation of ASU integration and the potential performance gains available through the continued use of gas turbine advances. Emphasis is placed on system design choices that favor either low initial investment cost or low operating cost for a given IGCC system output.

96/04208 Japan tests air blown IGCC

Recent runs on a pilot plant have convinced Mitsubishi that air blown gasification is feasible for IGCC systems. They are now making plans for a full size installation.

System Evaluation and LBTU Fuel Combustion Studies for IGCC Power Generation

The integration of gas turbines and combined cycle systems with advances in coal gasification and gas stream cleanup systems will result in economically viable IGCC systems. Optimization of IGCC systems for both emission levels and cost of electricity is critical to achieving this goal. A technical issue is the ability to use a wide range of coal and petroleum-based fuel gases in conventional gas turbine combustor hardware. In order to characterize the acceptability of these syngases for gas turbines, combustion studies were conducted with simulated coal gases using full-scale advanced gas turbine (7F) combustor components. It was found that NOx emissions could be correlated as a simple function of stoichiometric flame temperature for a wide range of heating values while CO emissions were shown to depend primarily on the H2 content of the fuel below heating values of 130 Btu/scf (5125 kJ/NM3) and for H2/CO ratios less than unity. The test program further demonstrated the capability of advanced can-annular combustion systems to burn fuels from air-blown gasifiers with fuel lower heating values as low as 90 Btu/scf (3548 kJ/NM3) at 2300°F (1260°C) firing temperature. In support of ongoing economic studies, numerous IGCC system evaluations have been conducted incorporating a majority of the commercial or near-commercial coal gasification systems coupled with “F” series gas turbine combined cycles. Both oxygen and air-blown configurations have been studied, in some cases with high and low-temperature gas cleaning systems. It has been shown that system studies must start with the characteristics and limitations of the gas turbine if output and operating economics are to be optimized throughout the range of ambient operating temperature and load variation.

Coal Gasification for Integrated Gasification Combined Cycle Power Generation

A number of coal gasifiers applicable to IGCC are under development or at the demonstration stage. These include moving bed, fluidised bed, entrained flow and molten bath types. The efficiency of an IGCC system increases as the temperature of the gas entering the turbine increases. Practical temperatures are currently limited by turbine blade materials and by the system used to clean the gas prior to entering the turbine. Work on hot gas cleaning systems, turbine blade materials and blade cooling techniques are under way. The main requirements of the gasification system are to provide a high temperature, high pressure gas with a minimum of impurities.