Input fuel availability, rate

The input requirements for post-flashover types of models can be quite broad. Besides the compartment and vent dimensions, detailed fuel combustion characteristics are often needed. The fuel characteristics include the fraction of carbon, hydrogen, nitrogen, and oxygen that make up the fuel, the burning efficiency, and the quantity of fuel available for burning. Mechanical ventilation flow rates and the material properties of the compartment boundaries may be necessary. Some models can account for the heat transfer through the boundaries in detail, and may even allow the user to supply time-dependent material properties. An example of a post-flashover fire model is COMPF (Babrauskas, 1979). 

A typical heat balance for Run LSF 34 on No. 6 oil is given in Table V. The calculated efficiencies are also given in the table. Heat input terms consist of the input heat from the fuel, the fuel sensible heat, and the makeup water sensible heat. The heat available from combustion of the fuel is calculated from the measured volumetric flow rate, the measured fuel heating value, and the measured fuel density at the nozzle temperature. The fuel sensible heat contains the fuel mass flow rate, the measured temperature at the nozzle, a reference temperature, and an estimated specific heat for the oil of 0.480 Btu/lb°F. The specific heat was taken from graphical information in the ASME Power Test Code. Similarly, the water sensible heat calculation contains a tabular value... 

Normal weathering processes that occur in nutritious soils release nutrients, but they are often not available at rates that promote maximum biomass yields. Fertilization is usually necessary to maximize yields. Since nitrogenous fertilizers are currently manufactured from fossil fuels, mainly natural gas, and since fertilizer needs are usually the most energy intensive of all the inputs in a biomass production system, a careful analysis of the integrated biomass production-conversion system is necessary to ensure that net energy production is positive. Trade-offs between synfuel outputs, nonsolar energy inputs. 

Coauthor Shannon has equipped furnaces with inputs 30 to 40% greater than the calculated need when new. He has found that they have used all the fuel capacity at some occasion in the first three years, and that after ten years all the furnaces have used all the available fuel input rate, quite often to make up for aging losses or because of a need (by the process) to extend the heating capacity of the furnace. 

Gross heat input required = (heat needed)/(% available heat/100) = 22 / 18 = fuel rate in each zone. 

Steam atomizers are available in sizes up to 300 x 10 Btu/h input—about 16,500 lb (7500 kg) of oil per hour. Oil pressure is much lower than that required for mechanical atomizers. Maximum oil pressure can be as much as 300 Ib/in (2040 kPa) and maximum steam pressure 150 Ib/in (1020 kPa). The steam atomizer performs more efficiently over a wider load range than other types. It normally atomizes the fuel properly down to 20 percent of rated capacity. 

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