Primary combustor

Control of SO is intrinsic to the MHD process because of the strong chemical affinity of the potassium seed in the flow for the sulfur in the gas. Although the system is operated fuel-rich from the primary combustor to the secondary combustor, the predominant sulfur compound in the gas is sulfur... 

The resulting overall energy balance for the plant at nominal load conditions is shown in Table 3. The primary combustor operates at 760 kPa (7.5 atm) pressure the equivalence ratio is 0.9 the heat loss is about 3.5%. The channel operates in the subsonic mode, in a peak magnetic field of 6 T. AH critical electrical and gas dynamic operating parameters of the channel are within prescribed constraints the magnetic field and electrical loading are tailored to limit the maximum axial electrical field to 2 kV/m, the transverse current density to 0.9 A/cm , and the Hall parameter to 4. The diffuser pressure recovery factor is 0.6. 

As shown in Fig. 14.24, a self-regulating oxidizer feeding mechanism is used to eliminate the liquid oxidizer pumping system. A flow of the pressurized fuel-rich gas generated in tlie primary combustor forces the oxidizer tank to supply the liquid oxidizer to the secondary combustor. Simultaneously, the fuel-rich gas is injected into the secondary combustor and reacts with the atomized oxidizer. The fuel-rich gas is injected from the primary combustor into the secondary combustor through the fuel gas injector under condihons of a choked gas flow. The pressure in the primary combustor is approximately double that in the secondary combustor. This system is termed a gas-pressurized system. 

When a turbo pump is used to obtain high oxidizer fuel flow, this is also operated by the fuel-rich gas generated in the primary combustor. Since the fuel-rich gas is at a higher pressure than the pressure in the secondary combustor, it is used to operate the oxidizer pump and is then used as a fuel component in the secondary... 

One operating concern for a rich combustor is the occurrence of high combustor wall temperatures. In a fuel-rich combustor, air cannot be used to film-cool the walls and other techniques (e.g., fin cooling) must be employed. The temperature rise of the primary combustor coolant was measured and normalized to form a heat flux coefficient which included both convective and radiative heat loads. Figure 7 displays the dependence of this heat flux coefficient on primary combustor equivalence ratio. These data were acquired in tests in which the combustor airflow was kept constant. If convective heat transfer were the dominant mechanism a constant heat flux coefficient of approximately 25 Btu/ft -hr-deg F would be expected. The higher values of heat flux and its convex character indicate that radiative heat transfer was an important mechanism. 

NO Dependence on Primary Combustor Equivalence Ratio for No. 2 Petroleum Distillate Fuel... 

The average heat flux coefficient to the primary combustor wall is plotted for the fuels in Figure 9. The results in general displayed a convex character as was observed with NO. 2 fuel. The level of the heat transfer coefficient and its convex trend indicates the importance of radiative heat transfer for these fuels. The maximum value of the coefficient for SCR-II fuel exceeded the maximum for other fuels by 30%. The hydrogen content of SCR-II was less than that for the other fuels tested which apparently resulted in a more intense radiating medium. 

Comparison of Primary Combustor Wall Heat Loading for Coal-Derived Fuels at Baseload... 

Again the maximum is observed at primary combustor equivalence ratios close to that desired for minimum N0X emission operation. 

Influences on the emissions and the heat flux to the primary combustor wall are presented in this section. Comparisons with data acquired by Westinghouse Electric Corporation in another EPRI-sponsored contractual program (RP989-1) in which similar test fuels were combusted in a conventional, lean combustor are also presented (3) ... 

N0X Emissions. The nitrogen content in the distillate fuels ranged from 0.0 to 0.75 wt%. The influence of this range on N0X emissions is displayed in Figure 11. The values plotted correspond to the minimal N0X level for each fuel. Since the minima occurred over a small range of primary combustor equivalence ratio (1.5 << >p <1.57) these data also represent operation at constant combustor conditions. As can be observed, the N0X emissions were independent of fuel nitrogen. An... 

Dependence of Primary Combustor Heat Load on Fuel Hydrogen... 

Primary combustor heat load increased with hydrogen deficient fuels, and maximized near values of heat flux with fuel hydrogen content for the water-cooled, staged combustor was consistent with air-cooled, lean combustor data. 

LI incinerators are usually refractoiy-lined chambers (horizontal, vertical orientation up or down), generally cylindrical, and equipped with a primary combustor (waste... 

In what is called a reheat enhanced gas turbine , the California Energy Commission proposed a decade ago (Anon, 1997c) to reform or partially oxidise a mixture of steam and a combustible hydrocarbon (e.g. methane) to produce a hydrogen-rich fuel used for the primary combustor and a reheat combustor upstream of the turbine final stage. Auto-ignition of hydrogen-rich gas into the gas flow path between the stages is carried out. 

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