Sampling calorific value

Sample Calorific Value (MJ kg ) Moisture %) Ash (%) Volatile Matter (%) Fixed Carbon (%) Total Sulfur (%)... 

The analyst now has available the complete details of the chemical composition of a gasoline all components are identified and quantified. From these analyses, the sample s physical properties can be calculated by using linear or non-linear models density, vapor pressure, calorific value, octane numbers, carbon and hydrogen content. 

Calorific Value. To determine calorific value, a sample is placed in a bomb, pressurized with oxygen, and ignited. The temperature rise in the water bath of the calorimeter surrounding the bomb is used to determine the calorific value (D2015, D3286, or D1989) (18). 

The analyses of gases in the oil industry comprises the determination of the inert gases (He, Hj, O2, Ar and N2), low-boiling compounds (CO, CO2, H2S, COS) and the lower hydrocarbons, saturated and unsaturated, up to hexane. Some special samples. Such as natural gas, have to be analysed for low concentrations of higher-boiling compounds (up to CiqS) since such compounds have an important influence on the calorific value and dew point. 

Table 2.2 Elemental analyses (wt.%) and calorific values (FIFIV, MJ/kg) of biomass samples...

Proximate analysis, determination of moisture content of the general analysis sample of coke Proximate analysis, determination of volatile matter content Proximate analysis, determination of ash content Determination of gross calorific value Ultimate analysis of coal and coke, determination of carbon and hydrogen content, high temperature combustion method Liebig method... 

The first method (ASTM D-2361) offers a choice of two procedures for combusting the coal sample. In the bomb combustion procedure, the oxygen bomb used is the same as, or very similar to, that used in determination of the calorific value (ASTM D-2015 ASTM D-3286). 

The calorific value of coal is an important property. For example, the gross calorific value can be used to compute the total calorific content of the quantity of coal or coke represented by the sample for payment purposes. It can also be used to compute the calorific value versus sulfur content to determine whether the coal meets regulatory requirements for industrial fuels. The gross calorific value can be used to evaluate the effectiveness of beneficiation processes. Finally, the gross calorific value can be required to classify coal (ASTM D-388). 

The common method of determining the gross calorific value of coal is with either an adiabatic calorimeter (ASTM D-2015 this test method was discontinued without replacement in 2000 but is still in use in many laboratories) or an isothermal bomb calorimeter (ASTM D-3286). In these methods, a weighed sample is burned in an oxygen bomb covered with water in a container surrounded by a jacket. 

An adiabatic calorimeter is a calorimeter that has a jacket temperature adjusted to follow the calorimeter temperature so as to maintain zero thermal head, and the test method (ASTM D-2015, ISO 1928) consists of burning the coal sample in the calorimeter, and the jacket temperature is adjusted during the burning so that it is essentially the same as the calorimeter water temperature. The calorific value is calculated from observations made before and after the combustion. In the isothermal method (ASTM D-3286 ISO 1928), the calorific value is determined by burning a weighed sample of coal in oxygen under controlled conditions, and the calorific value is computed from temperature observations made before, during, and after combustion with appropriate allowances made for the heat contributed by other processes. The value computed for the calorific value of coal... 

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. 

In some instances, an adiabatic bomb calorimeter may not be available or the sample may be too small for accurate use. To combat such problems, there is evidence that differential thermal analysis (DTA) is applicable to the determination of the calorific value of coal. Data obtained by use of the DTA method are in good agreement with those data obtained by use of the bomb calorimeter (Munoz-Guillena et al., 1992). 

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. 

Sample Proximate analysis (d.b.%) Ultimate analysis (d.a.f.%) C/ XH (d.b.%) Petrographic analysis Calorific value (kcal/kg)... 

Same as (a) above except that the amount of sample is about 2mg (but modified according to the calorific value). 

On a logarithmic scale, plot the calorific value against the value obtained by subtracting 25 0 C from the exothermic start temperature. When the data point plotted is located on or above the straight line passing through the data points for DNT and BPO (calorific values are multiplied by 0.7 and 0.8,respectively),the sample is considered dangerous 3. 

The method of determining heats of combustion has been described above, for carbon. This method, with use of a bomb calorimeter, is the customary basis for determining the value of a fuel, such as coal or oil. A weighed sample of the fuel is placed in the bomb calorimeter, the bomb is filled with oxygen, and the fuel is burned. The fuel value or calorific value of the fuel is considered to be measured by its heat of combustion, and when large amounts of fuel are purchased the price may be determined by the result of tests in a bomb calorimeter. 

The physico-chemical properties of the oil samples were measured according to ASTM methods density D 369 kinematic viscosity- modified D 445-88 [9], flash point D-93 gross calorific value D4809 water content D-1744 and ash content D 482. The apparent viscosity was measured using a Brookfield viscometer, LVDV III+. The content of the methanol insoluble materials (MIM) was determined according to the method described by Oasmaa et al. [13],... 

The High Calorific Value of the oil shales was determined by a "bomb" calorimeter on more than 90 composite samples from different deposits and on one-meter samples along borehole sections. The average value is lOOOKcal/Kg and the highest value measured was 1790Kcal/Kg. The correlation between organic matter content and the calorific value is more than significant (R=0.96). The equation for the Ef e deposit is ... 

The produced combustible gas of the demonstration plant has a different composition from that of the small pilot plant. The former includes more carbon monoxide and less carbon dioxide than the latter. The difference in gas composition between the two tests seems to come from the fact that in case of the larger reactor, supplied solid waste is heated up promptly and over-cracking is prevented. Because of the high carbon monoxide content, the calorific value of the demonstration plant is higher than that of the small reactors. Sampling of the combustible gas for... 

The compositions of the samples of produced gases from the pyrolysis furnace are as shown in Table II. The compositions of pyrolytic gases given in Table II are, as mentioned above, experimental values when the calorific value of the refuse is in the range of Hu = 1,265 1,330 kcal/kg. 

Sample Iodine Value by Acid No. (mg KOH/g) Saponification value Refractive Index Calorific value (MJ/Kg)... 

An alternate method of calculation of the calorific value, when an experimental determination is not available or cannot be made conveniently, involves an estimate of this property (ASTM D-6446). In this test method, the net heat of combustion is calculated from the density and sulfur and hydrogen content, but this calculation is justifiable only when the fuel belongs to a well-defined class for which a relationship between these quantities has been derived from accurate experimental measurements on representative samples. Thus the hydrogen content (ASTM D-1018, ASTM D-1217, ASTM D-1298, ASTM D-3701, ASTM D-4052, ASTM D-4808, ASTM D-5291, IP 160, IP 365), density (ASTM D-129, ASTM D-1250, ASTM D-1266, ASTM D-2622, ASTM D-3120, IP 61, IP 107), and sulfur content (ASTM D-2622, ASTM D-3120, ASTM D-3246, ASTM D-4294, ASTM D-5453, ASTM D-5623, IP 336, IP 373) of the sample are determined by experimental test methods, and the net heat of combustion is calculated with the values obtained by these test methods based on reported correlations. 

The basis for the assignment of an enthalpy of formation to a natural material consists of the chemical composition, the structure information, and the calorific value. To determine the calorific value the prepared sample is completely oxidized (burned) in a calorimeter in an excess of oxygen. The heat liberated in this exothermic process is determined as the calorific value Qp>0. In the case of endothermic processes, such as calcination, Qp would be negative. 

The quantity of solid fuels used is generally controlled by some form of batch weighing which gives a high consistency. Variations in calorific value are, however, more problematic. They are generally resolved by a combination of blending deliveries and determining the calorific value daily on a representative sample. 

The gross calorific value is determined by measuring the heat released when a sample of fuel is ignited in oxygen. The initial and final temperatures are such that the water vapour produced by the combustion is condensed. Thus the gross calorific value includes the latent heat of condensation of the water. 

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