Bomb Calorimeter Provides a Measure of a Feed

Bomb Calorimeter

Bomb calorimeter data are increasingly applied to environmental studies concerned with prevention of forest fires and fire fighting through the design of energy and risk index maps.

From: Dictionary of Energy (Second Edition) , 2015

B

In Dictionary of Energy (Second Edition), 2015

bomb calorimeter Measurement. an apparatus that can measure heats of combustion, used in various applications such as calculating the calorific value of foods and fuels.

See below.

bomb calorimeter An apparatus primarily used for measuring heats of combustion. The reaction takes place in a closed space known as the calorimeter proper, in controlled thermal contact with its surroundings, the jacket, at constant temperature. This set, together with devices for temperature measurement, heating, cooling, and stirring comprise the calorimeter. The calorimeter proper is usually a metal can with a tightly fitting lid containing water, stirred continually, in which the bomb itself is situated. It consists of a sealed heavy-walled container in which the reactants are allowed to react, under constant volume conditions, following the ignition of the combustible matter in an oxygen atmosphere. Gases at high pressures are frequently used, hence the name. In 1878, Paul Vieille (1854–1934) developed the first bomb calorimeter which was used for measuring heats of explosion at the French service of explosives in Paris. However, this bomb was attributed by many authors to M. Berthelot (1827–1907). For many years, the use of the bomb (static) was limited to studies on C, H; C,H,O, and C, H, O, N compounds and could not be used to study those containing sulfur or halogen atoms. It was not until the use of the moving bomb technique, in 1933, that these substances could be studied. The method was improved from 1948 and onward in the universities of Lund (Sweden) and Bartlesville (U.S.). The use of oxidants other than oxygen was introduced in 1961.The use of bomb calorimetry has recently been extended to industries relating to foodstuffs, animal feed, cement, and combustible waste. Bomb calorimeter data are increasingly applied to environmental studies concerned with prevention of forest fires and fire fighting through the design of energy and risk index maps.

Lisardo Núñez Regueira

Universidade de Santiago de Compostela, Spain

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Influence of fuel injection timing and nozzle opening pressure on a CRDI-assisted diesel engine fueled with biodiesel-diesel-alcohol fuel

D. Babu , R. Anand , in Advances in Eco-Fuels for a Sustainable Environment, 2019

13.2.5.4 Calorific value

The Bomb Calorimeter (Model-IKA C2000) was used to measure the cross calorific value of the solid and liquid samples. It is a constant-volume type calorimeter that measures the heat of a particular reaction or measures the calorific value of the fuels. Bomb calorimeters are built in such a way that they can withstand the large pressure produced within the calorimeter due to the reaction or burning of fuel. The electrical energy is used as an ignition source for the burning of testing fuels, and the heating filament is made up of tungsten materials. In the bomb calorimeter, I g of the sample was taken in the crucible and was electrically ignited to burn with the presence of pure oxygen. During the combustion, heat was released and a rise in temperature was measured. The dry benzonic acid was used as a fuel to measure the effective heat capacity of water.

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Analytical Techniques

Prabir Basu , in Biomass Gasification, Pyrolysis and Torrefaction (Third Edition), 2018

14.2 Heating Value

The higher heating value (HHV) can be measured in a bomb calorimeter using ASTM standard D-2015 (withdrawn by ASTM 2000, and not replaced).

The bomb calorimeter consists of pressurized oxygen "bomb" (30 bar), which houses the fuel. A 10 cm fuse wire connected to two electrodes is kept in contact with the fuel inside the bomb. The oxygen bomb is placed in a container filled with 2 l of deionized water. The temperature of the water is measured by means of a precision thermocouple. A stirrer stirs the water continuously. Initially, the temperature change would be small (Fig. 14.2) as the only heat generated would be from the stirring of the water molecules. After the temperature is stabilized, the sample is fired, meaning a high voltage is sent across the electrodes and through the fuse wire. The electric current passing through the fuse wire would almost instantly ignite and combust the fuel sample in oxygen. The water absorbs the heat, released by the combustion of the sample, resulting in a sharp rise in the water temperature (Fig. 14.2). The temperature continues to rise for some time before leveling off. The water temperature is continuously recorded till the temperature readings are stable. Knowing the heat capacity of the bomb calorimeter material, water, and of the fuse wire, one can calculate the exact amount of heat released by combustion of the sample.

Figure 14.2. Temperature profile from a bomb calorimeter experiment.

By knowing the initial mass of the fuel sample, the heating value of the sample can be calculated by dividing the heat released by the mass of the sample. As the product of combustion is cooled below the condensation temperature of water, this technique gives the HHV of the fuel.

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Test Methods for Petroleum Products

Wilfrid Francis , Martin C. Peters , in Fuels and Fuel Technology (Second Edition), 1980

(a) Total

By combustion in a bomb calorimeter. This is best carried out in the bomb calorimeter in conjunction with the determination of calorific value (cf. Item 4, above). The contents of the bomb are washed with distilled water into a beaker. Hydrochloric acid is added and the solution raised to boiling point. Barium chloride is added drop by drop to the boiling solution to precipitate the sulphuric acid as granular barium sulphate. After cooling, and standing for 24 hr, the precipitate is filtered off on an ashless paper, washed, ignited and weighed as barium sulphate.

$\%\text{wt}.\text{of}\text{sulphur=}\frac{\text{Wt}\text{.of}\text{barium}\text{sulphate}\times 13.73}{\text{Wt}.\text{of}\text{oil}\text{sample}}$

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Fuels*

In Smithells Metals Reference Book (Eighth Edition), 2004

(A) CALORIFIC VALUE

In the absence of a bomb calorimeter determination, approximate values may be calculated for petroleum oils, or tars. However, the correlations are separate for each group.

$\begin{array}{ll}\text{Gross calorific value}=& 51.91-8.79d^2-\{0.519\text{undefined}1-0.087\text{undefined}9d^2(\%{\text{H}}_2\text{O}+\%\text{ash}+\%\text{S})\}\\ & +0.094\text{undefined}2(\%\text{S}){\text{ MJ kg}}^{-1}\\ \hfill \text{or}& 22.320-378\text{undefined}0d^2-\{223-37.8d^2(\%{\text{H}}_2\text{O}+\%\text{ash}+\%S)\}\\ & +40.5(\%S){\text{ Btu lb}}^{-1}\\ & \simeq 59.91-8.79d^2{\text{MJ kg}}^{-1}\\ \hfill \text{or}& 22\text{undefined}320-3\text{undefined}780d^2{\text{ Btu lb}}^{-1}\text{undefined}(\text{reference}17)\end{array}$

$\begin{array}{cc}\text{Net calorific value}=& 46.5+3.14d-8.84d^2{\text{ MJ kg}}^{-1}\hfill \\ \hfill \text{or}& 20\text{undefined}000+1\text{undefined}350d-3\text{undefined}800d^2{\text{ Btu lb}}^{-1}\text{undefined}(\text{reference}17)\end{array}$

where d is the specific gravity (relative density) at 15.6°C (60°F) for petroleum oils.

The net calorific values are about 2.8 MJ kg⁻¹ (1 200 Btu lb⁻¹) less than the gross values for distillate fuels down to about 2.3 MJ kg⁻¹ (1 000 Btu lb⁻¹), less for heavy fuel oils.

For tar fuels:

$\begin{array}{cc}\text{Gross calorific value}=& 0.337(\%C)+1.44(\%\text{ H}-\frac{1}{8}\%\text{O})+0.093\left(\%\text{S}\right){\text{MJ kg}}^{-1}\hfill \\ \hfill \text{or}& 145\left(\%\text{C}\right)+620\left(\%\text{H}-\frac{1}{8}\%\text{O}\right)+40(\%\text{S}){\text{ Btu lb}}^{-1}\text{undefined}(\text{reference}18)\\ \text{Net calorific value}=& 0.75(\text{gross CV}+1.09){\text{ MJ kg}}^{-1}\hfill \\ \text{or}& 0.75(\text{gross CV}+4\text{undefined}700){\text{ Btu lb}}^{-1}\text{undefined}(\text{reference}18)\hfill \end{array}$

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Coal

Balasubramanian Viswanathan , in Energy Sources, 2017

Need for Net Calorific Value

Calorific values as determined with the bomb calorimeter represent the heat produced by a unit weight of coal when completely oxidized, when the products of the combustion are cooled to room temperature. This value is not realized in practice because the products of combustion are not cooled to room temperature before being discharged to waste.

Sensible heat is lost in the hot waste products. Apart from this, further heat loss occurs in practice as the latent heat of steam in the hot waste gases. Water is present as such because moisture in the air-dried coal and a further amount are formed by the combustion of the hydrogen combined with carbon in the coal. In the bomb calorimeter the moisture is first evaporated and then condensed to liquid water. Similarly the water formed as steam by combustion is condensed to liquid water; the latent heat of condensation of the steam is recovered. In industrial practice water from both sources is discharged as steam, so that both latent heat and sensible heat are lost. It is therefore useful to distinguish the calorific value as determined with the bomb calorimeter by calling it the gross calorific value.

A lower value can be derived, which is the gross calorific value minus the latent heat of condensation at 15.5°C of all of the water involved. This is named the net calorific value. The net calorific value is a more realistic statement of realizable potential heat than the gross value.

The correction to the gross calorific value is 586   cal/g water (latent heat of steam   =   586   cal/g). The water referred to is the weight of water produced by the complete combustion of unit weight of coal plus the water existing as moisture in the coal. The former is calculated from a known hydrogen content of the coal:

Net calorific value   =   gross calorific value   − 586 (water as moisture + water formed from H₂)   cal/g.

The calorific value of coal has been used to exemplify gross and net calorific value. The same correction can be applied to any fuel of any physical state if care is taken with the units of weight or volume.

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Wood Products: Thermal Degradation and Fire

R.H. White , M.A. Dietenberger , in Encyclopedia of Materials: Science and Technology, 2001

2.2 Rate of Heat Release

Heat of combustion measured in an oxygen bomb calorimeter is the total heat available. Higher heating values for wood are about 20  kJkg⁻¹. Heat of combustion depends on the relative lignin and holocellulose and extractive contents of wood. Cellulose and hemicellulose have a higher heating value of 18.6   kJkg⁻¹, whereas lignin has a higher heating value of 23.2–25.6   kJkg⁻¹. Higher heating values of extractives are about 32–37   kJkg⁻¹.

In a fire situation, the contribution of combustible materials to a fire depends more on the rate of heat release (RHR) rather than the total heating value. The best known method for determining RHR is the American Society of Testing Materials (ASTM) E1354 (also ISO 5660), known as the cone calorimeter which is based on the oxygen consumption method. With untreated wood, the RHR increases to a peak shortly after ignition, then decreases to a lower semiconstant RHR when exposed to a constant heat flux. The char layer provides thermal insulation from the fire and gradually reduces the rate of charring propagation, thus also the RHR. Wood specimens tested with an insulating backing will also have a second peak in RHR due to termination of the thermal wave and the afterglow phenomena. In general, the averaged effective heat of combustion in cone calorimeter tests of wood is about 65% of the higher heating value from an oxygen bomb.

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Energy Balance and Regulation of Food Intake

Joseph Feher , in Quantitative Human Physiology (Second Edition), 2017

•

Describe a whole-body calorimeter

•

Describe a bomb calorimeter

•

List the Atwater factors

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Be able to use the Atwater factors to calculate the energy content of food

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Describe indirect calorimetry

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Use the volume of O₂ consumed, CO₂ produced, and urinary nitrogen to calculate the proteins, carbohydrates, and fats that are burned

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Use allometric formulas to estimate BMR

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Give subjective evidence that body weight is homeostatically regulated

•

Distinguish between satiety signals and adiposity signals in regulation of food intake

•

Identify the satiety center and the "feeding center" and why they are so designated

•

List short-term signals that regulate food intake

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List long-term signals that regulate food intake

•

Identify the following abbreviations for neurotransmitters involved in food regulation: POM, CART, AgRP, CCK, NPY

•

Describe what is meant by a "glucose stat" and distinguish between glucose-sensitive and glucose-responsive neurons

•

Indicate the part of the brain where food intake signals are integrated with hormonal signals

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28th European Symposium on Computer Aided Process Engineering

Hongliang Qian , ... Rafiqul Gani , in Computer Aided Chemical Engineering, 2018

2.2 Thermodynamic data prediction

The value of energy change of combustion reaction in oxygen bomb calorimeter is HHV:

(4) $\begin{array}{l}-0.001M\times \mathit{HHV}=x{\Delta }_{\mathrm{f}}{H}_{\mathrm{m},{\mathrm{CO}}_2}+\frac{y}{2}{\Delta }_{\mathrm{f}}{H}_{\mathrm{m},{\mathrm{H}}_2\mathrm{O}\left(1\right)}+\frac{a}{2}{\Delta }_{\mathrm{f}}{H}_{\mathrm{m},{\mathrm{N}}_2}+b{\Delta }_{\mathrm{f}}{H}_{\mathrm{m},S{\mathrm{O}}_2}\\ -{\Delta }_{\mathrm{f}}{H}_{\mathrm{m},{\mathrm{C}}_x{\mathrm{H}}_y{\mathrm{O}}_z{\mathrm{N}}_a{\mathrm{S}}_b}-\left(x+\frac{y}{4}-\frac{z}{2}+b\right){\Delta }_{\mathrm{f}}{H}_{\mathrm{m},{\mathrm{O}}_2}\end{array}$

where M is molecular weight of dry biomass, 100g mol^-1. With the help of a prediction model of HHV proposed in our previous study (Eq. (5)) (Qian et al., 2016), the final calculation equation of standard molar enthalpy of formation of dry biomass was obtained (Eq.(6)).

(5) $\mathit{HHV}=874.08\left(\frac{1}{3}\mathrm{C}+\mathrm{H}\right)\mathrm{kJ}\cdot {\mathrm{kg}}^{-1}$

(6) ${\Delta }_{\mathrm{f}}{H}_{\mathrm{m},\mathrm{C}x\mathrm{H}y\mathrm{O}z\mathrm{N}a\mathrm{S}b}^o=-32.762\mathrm{C}-141.781\mathrm{H}-9.258\mathrm{S}+0.874M\left(\frac{1}{3}\mathrm{C}+\mathrm{H}\right)\mathrm{kJ}\cdot {\mathrm{mol}}^{-1}$

Standard molar entropy S _m ^o (Song et al., 2011) and heat capacity C _p (Rath et al., 2003) of dry biomass were predicted via Eq. (7) and Eq.(8), respectively.

(7) $S_m^o=M\times \left(0.0055\mathrm{C}+0.0954\mathrm{H}+0.0096\mathrm{O}+0.0098\mathrm{N}+0.0138\mathrm{S}\right)\mathrm{J}\cdot {\mathrm{mol}}^{-1}\cdot {\mathrm{K}}^{-1}$

(8) $C_p=0.001{\mathit{Mc}}_p=0.001M\left(-212.928+4.8567T\right)\mathrm{J}\cdot {\mathrm{mol}}^{-1}\cdot {\mathrm{K}}^{-1}$

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METHODS OF SOLVENT DETECTION AND TESTING

GEORGE WYPYCH , ... JAMES L. BOTSFORD , in Handbook of Solvents (Second Edition), Volume 2, 2014

14.1.6 CALORIFIC VALUE

The heat of combustion of liquid hydrocarbon fuels can be determined with bomb calorimeter. ¹⁶ Two definitions are used in result reporting: gross heat of combustion (the quantity of energy released from fuel burned in constant volume with all products gaseous except water which is in liquid state) and net heat of combustion (the same but water is also in a gaseous state). These determinations are useful in assessing the thermal efficiency of equipment used for generation of power or heat. The results are used to estimate the range of an aircraft between refueling stops which is a direct function of heat of combustion. The calorimeter bomb is standardized against benzoic acid standard. Net and gross heats of combustion are reported. A specific method is used for aviation fuels. ¹⁷ This method reports results in SI units and the measurements are made under constant pressure. The method is applicable for aviation gasolines or aircraft turbine and jet engine fuels. The method is used when heat of combustion data are not available. An empirical equation was developed which gives net heat of combustion based on the determined values of aniline point (ASTM D 611) and API gravity (ASTM D 287). If the fuel contains sulfur, a correction is applied for sulfur determined according to ASTM D129, D 1266, D 2622, or D 3120 (the method selected depends on the volatility of the sample).

Gross calorific value and ash content of waste materials can be determined by a calorimetric method. ¹⁹ After a calorimetric analysis, the bomb washing can be used to determine of mineral content by elemental analysis. The sample is burned under controlled conditions in oxygen. The calorimeter is standardized by burning known amount of benzoic acid. The formation of acids can additionally be determined by titration.

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