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Show Selected specifications of the series of gas turbines BBC manufactures and offers for heavy duty industrial use are listed in Table 1. Figure 2 is a cutaway view of a type 9 gas turbine, showing from the right to the left the generator, the gears, the compressor, the turbine and the exhaust gas diffuser. On top of this single shaft thermal block, there is the single combustor with one burner in the center. III. BURNING BLAST FURNACE GAS IN THE GAS TURBINE During the decade of the fifties, Brown Boveri installed 21 machines for steelworks in replacement for reciprocating gas engines [2]. These machines, fired with blast furnace gas, produced electricity and drove the blast blowers. Changes introduced in the smelting technology, however, led to reduced coke consumption and sharp decline in the availability of blastfurnace gas; hence most operations became economically unattractive. One of the most durable plants for blast furnace gas service was set into operation in 1959 at the Donawitz Steelworks Loeben, Austria location, as shown in Figure 3. After logging 175,000 service hours, the 17 MW capacity machine is still operational. The blast furnace gas produced at Donawitz, Jl« OC given in Table 2, had extremely low (80-90 Btu/scf) heating value; hence /L « - - •-<- - - -«-' •»• ™ ' - - « - - - >' burned steadily without oil addition. • <° A. (^ Initial problems with the Donawitz and other plant operations were dust related. Under the original design, the compressed filtered fuel gas was preheated in a tubular exchanger by the exhaust gas, similarly to air preheat. After short operation, due to the catalytic effect of entrained fine iron particles, carbon formation set in from the CO containing fuel gas and the exchanger was blocked. To eliminate the problem, electrostatic precipitators were installed. Dust count in the gas entering the compressor was reduced to 1 mg/Nm3 and the gas preheater was bypassed. Similar cleanup of the intake air became also necessary to avoid the contamination of air compressor blades. In spite of this precaution after 24,000 service hours, corrosion of the trailing edges of the first two rows of the gas turbine 1.4.3 |