Gross calorific values, energy

Gross Calorific Value factor (GCV factor) is calculated to convert between nominations that are done in energy units, and bookings that are done in volume units. 

The calorific value is a direct indication of the heat content (energy value) of the coal and represents the combined heats of combustion of the carbon, hydrogen, nitrogen, and sulfur in the organic matter and of the sulfur in pyrite and is the gross calorific value with a correction applied if the net calorific value is of interest. 

After firing, the contents of the bomb are washed into a beaker and titrated with standard sodium carbonate solution to determine the amount of acid (nitric acid, HN03 and sulfuric acid, H2S04) produced in the combustion. Corrections for the amount of acid, the amount of fuse wire used in firing, and the sulfur content of the sample are then made to the total heat produced in the calorimeter (energy equivalent times corrected temperature rise) to determine the gross calorific value of the solid fuel. 

Energy equivalent, heat capacity, or water equivalent energy required to raise the temperature of the calorimeter an arbitrary unit when multiplied by the corrected temperature rise, adjusted for extraneous heat effects, and divided by the weight of the sample, gives the gross calorific value. 

Gross calorific value (gross heat of combustion at constant volume) heat produced by combustion of a unit quantity of a solid or liquid fuel when burned at constant volume in an oxygen bomb calorimeter under specified conditions, with the resulting water condensed to a liquid not applied to gaseous fuels and applies to a volatile liquid fuel only if it is suitably contained during the measurement closely related to the internal energy of combustion for the same reaction at constant standard temperature and pressure. 

Gross calorific value This is the heat value of energy per unit volume at standard conditions, expressed in terms of kilocalorie per cubic Newton meter (kcal/Nm3) or other equivalent units. 

Energy in the char and gas averaged 77% of the gross calorific value of the feedstock. In these experiments, energy to pyrolyse the feedstock was supplied by propane. About 100 MJ were required to heat the kiln to 870 K. Another 121 MJ/h were required to maintain this temperature and 189 MJ/h were required to maintain a temperature of 1170 K. About 90% of this heat was lost in the exhaust and in an actual system most could be recovered for process heating. Calculations were made to predict thermal efficiencies of a self-sustaining system where a portion of the product is recycled and combusted to provide process heat thermal efficiencies of about 65% were predicted. 

The gross calorific value enables an evaluation of the total heating energy generated during the combustion process. The gross calorific value of the methyl esters was found to be, on average, about 5 and 7% lower than that of kerosene and automotive diesel fuel respectively, as shown in Table 2. 

Feedstock energy represents the energy of the fuel bearing materials that are taken into the system but used as materials rather than fuels. The quantities of hydrocarbon feedstocks that are taken into the system are represented in terms of their gross calorific value because, frequently, in the course of processing, some, if not all, of this feedstock may be converted to a fuel. It is a simple matter to convert from feedstock energy to mass if the calorific value is known since the energy content of a feedstock is simply the product (calorific value x mass). 

Gross calorific value is the energy obtained from a fuel when the combustion products are returned to the thermodynamic standard state and any water produced... 

XfPf is actually the on-site cost of the net energy requirement (NER). NER is part of the gross energy requirement (GER) of the process needed to give the required product less the calorific value (CV) of the product. That is,... 

One aspect of energy calculations that causes many problems in interpretation is the conversion factor used to convert fuel mass to energy. The conversion factor is called the calorific value of the fuel and represents the quantity of energy that can be derived from unit mass of fuel. There are, however, two types of calorific value—gross and net. 

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