Combustor heat load

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. 

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. 

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

It can be shown that the staged combustor heat flux data can be used to evaluate liner heat load in a manner equivalent to the temperature parameter often used for lean combustors (4 ). This is ... 

This section is a brief introduction to some of the important issues concerning the heat load in a furnace or combustor. In petrochemical production processes. 

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. 

Assessments of control, operabiHty and part load performance of MHD—steam plants are discussed elsewhere (rl44 and rl45). Analyses have shown that relatively high plant efficiency can be maintained at part load, by reduction of fuel input, mass flow, and MHD combustor pressure. In order to achieve efficient part load operation the steam temperature to the turbine must be maintained. This is accompHshed by the use of flue gas recirculation in the heat recovery furnace at load conditions less than about 75% of fiiU load. 

In order to show the effect, TPG model has been used to re-simulate the 15 kW load step decrease with a 1% turbine efficiency increase. Figure 8.20 shows a slight increase in the amplitude of the rotational speed transient behavior. However, as with the NETL model, the frequency is not much affected. Therefore, it is likely that some of the amplitude error from the NETL model comes from performance map. It is also possible that some of the difference comes from a different heat transfer model for the NETL post-combustor, V 304. 

Today s propulsion systems are required to produce larger and more rapid release of energy from smaller and more compact combustors, to cope with the demand for increased speed and range, and a wider operational envelope. Associated with these requirements are higher temperatures, increased heat transfer and thermal load, and frequent off-design operation. For current and future propulsion systems the following three major criteria are important ... 

The occurrence of frictional heating has important implications for the design of structural components. One concern is that components such as gas-turbine airfoils and combustors will be subjected to creep loading com-... 

The second issue is the improvement of the low-temperature performance of combustion catalysts, i.e., the activity at combustor inlet conditions. All the proposed catalytic combustor designs available today need a pilot flame, or a heat exchanger in the case of recuperative gas turbines, to heat the compressed combustion air to a temperature sufficient for ignition of the catalyst. The possibility of avoiding this pilot flame is considered very important, since it would further reduce NO emissions. The catalyst surface area and washcoat loading are very important for the low-tempcraturc activity. 

Prior to each run, the MSW hopper was loaded with MSW pellets the DSS feed tank was filled and the lime or clay (when needed) was mixed with the DSS the flue gas analyzers, pressure, and weight indicators were calibrated and the combustor and EHE were loaded with their respective dense and entrained bed material. A 650-675 C fluidizing gas stream was generated using a natural gas burner and was used to heat the bed. 

Regulation of process rate in response to load demand has been accomplished, A modulating type actuator simultaneously positions valves separately regulating generator air and gas combustor air flow rates. The rate of ash removal is regulated 1n proportion to fuel and air supply. The heat output demand is therefore matched by the air delivery rate to the machine. 

In the vast majority of cases, dioxin/furan emissions result from some contaminant in the load materials being heated in the combustor. A quick scan of most of... 

There are six components that may be important in industrial combustion processes (see Figure 1.16). One component is the burner that combusts the fuel with an oxidizer to release heat. Another component is the load itself that can greatly affect how the heat is transferred from the flame. In most cases, the flame and the load are located inside of a combustor, which may be a furnace, heater, dryer, or kiln that is the third component in the system. In some cases, there may be some type of heat recovery device to increase the thermal efficiency of the overall combustion system, which is the fourth component of the system. The fifth component is the flow control system used to meter the fuel and the oxidant to the burners. The sixth and last component is the air pollution control system used to minimize the pollutants emitted from the exhaust stack into the atmosphere. The first four system components are considered next. 

Because most development work has been done on non-oxide materials, particularly SiC fiber-reinforced SiC CMCs (SiC/SiC) with fiber interfacial coatings of either carbon or boron nitride, non-oxide CMCs are more advanced than oxide CMCs. Non-oxide CMCs have attractive high temperature properties, sueh as creep resistance and microstructural stability. They also have high thermal conductivity and low thermal expansion, leading to good thermal stress resistance. Therefore, non-oxide CMCs are attractive for thermally loaded components, such as combustor liners (see Figure 1-4), vanes, blades, and heat exchangers. 

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