Abstract
The externally fired gas turbine process works with a heat exchanger to heat a working medium to the gas turbine temperature. Compared with combined processes with integrated coal gasification or pressured pulverized coal firing there is no hot gas purification. Part 1 of this study (BWK 5/02) treated the structure, the different process variations, and the efficiency potential. The use of metallic and ceramic materials of construction as high temperature heat exchanger material was discussed. Part 2 treats the state of development of the EFCC (Externally Fired Combined Cycle) processes and introduces the design of a ceramic heat exchanger. In contrast to the combination processes with integrated coal gasification or pressurized pulverized coal firing, as a result of gas purification the gas turbine-compatible fuel gases or hot gases develop ahead of the gas turbine. The externally fired combined cycle works with a heat exchanger to heat clean gas that is satisfactory for gas turbine demands. This indirectly fired combination process presents an alternative to the combination processes with integrated coal gasification or pressurized firing. The discussion covers the state of the development (the EFCC process with metallic heat exchanger and EFCC process with ceramic heat exchanger); and design of a heat exchanger. With respect to its process efficiency, the EFCC process has a great potential. Process calculations gave efficiencies similar to those of coal gasification processes wherein as advantage there is the comparably simple connection. The separation of the gas turbine working medium from the flue gas makes possible besides the use of coal the use of other ash-containing fuels such as biomass. The presently available high temperature heat exchanger materials limit achievable gas turbine entrance temperatures using an exclusively solids fired EFCC process. To make use of the temperature level of the present gas turbine generation of 1400°C, further developments and modifications of materials of construction are required. There are problems to solve in corrosion resistance and manufacturing problems. For the materials of construction range to 1150°C it appears on the basis of studies in ash-containing flue gases oxide dispersion hardened super alloys are usable. Under these prevailing conditions an EFCC process with metallic materials of construction and natural gas firing in addition are possible.
| Translated title of the contribution | Power plant engineering. Externally fired gas turbine process. Potentials and state of development - 2 |
|---|---|
| Original language | German |
| Pages | 52-56 |
| Number of pages | 5 |
| Volume | 54 |
| No | 6 |
| Specialist publication | BWK- Energie-Fachmagazin |
| State | Published - 2002 |
| Externally published | Yes |