Calculation of the high heat value of biofuels

Abstract

Unique experimental data on the high heat value of biofuels -soy and rapeseed oils and methyl esters of the latter -which are in good agreement with the data of domestic and foreign researchers confirm the results of calculations: high erucic oil and its derivatives have a higher energy potential than low erucic oil. These data allow determining the indicator and effective indexes of operation of diesel (multifuel) engines with a high degree of reliability.With the shortage of liquid energy carriers of petroleum origin and to reduce the environmental hazard of diesel exhaust gases, alternative fuels from renewable feedstock sources -vegetable oils and their derivatives, are beginning to be used.In processing experimental data and calculations of the running cycle of diesel engines, it is important to know the precise value of the low heat value Q l of the fuel. The value of Q l is calculated with the high heat value Q h , which is determined calorimetrically according to GOST 21261"91 in isothermal and adiabatic conditions in a constant volume.The values of Q h and Q l of petroleum fuels and the equations for calculating them are widely known [1], and the experimental values of these quantities were systematized in [2] for biofuels from plant feedstock.Although these values are in satisfactory agreement with the values calculated with Mendeleev's equation, Q h was directly measured with a combustion calorimeter with a V-08MA liquid bomb. S i n c e G O S T 2 1 2 6 1 -9 1 c o v e r s l i q u i d f u e l s a n d h y d r o c a r b o n a n d o x y g e n -c o n t a i n i n g components, the recommended method for determination of Q h can also be considered suitable for oxygen-containing (9-10% O 2 ) vegetable oils and their derivatives.Calorimetric tests of samples of the following fuels [3] were conducted in the Laboratory of Thermal and Thermophysical Measurements at Khar'kov State Scientific-Research Institute of Metrology (KSSRIM): Sample 1 -RME: German rapeseed oil methyl esters, erucic acid C22:1* = 0.6%; density of esters = 877 kg/m 3 at 20°C; Sample 2 -RHRO: refined high erucic rapeseed oil, C22:1 ≈ 30%, density = 916 kg/m 3 at 20°C; *Designation of the erucic acid used in the chemistry of fats: C22 -formula C 22 H 42 O 2 ; the figure 1 after the colon designates the number of double bonds in the molecule. 0009-3092/06/4202-0144

Brassica carinata – a new molecular farming platform for delivering bio‐industrial oil feedstocks: case studies of genetic modifications to improve very long‐chain fatty acid and oil content in seeds

“…in lubricants, detergents, film processing agents and coatings, as well as in cosmetics and pharmaceuticals 66–70. Studies have confirmed that high erucic oil and its derivatives have a higher energy potential than low erucic oil 71. Compared to low erucic Brassica oils, high erucic oils are more suitable for biodiesel production because their iodine value is lower and within the European Union specifications 72.…”

Comparison of the physicochemical characteristics of biofuels and petroleum fuels

“…The weighted mean mo lecular weight is rep orted for SAG, WAG, RO, ROTG, ROME, HAME, SO, and CO. Table 1 An analysis of the many developments in this direction [14][15][16][17][18][19][20][21][22][23][24][25][26][27] showed that hopes for ensuring a number of advantages over petroleum fuels, namely, the excellent environmental characteristics of their production, storage, shipment, and use, have been placed on biofuel. The closeness of the chemical composition of biofuels to traditional fuels should in turn keep the performance properties unchanged.…”

Diesel biofuel viscosity and heat of combustion

“…We did not use the analogous foreign standards (ASTM 4809, ASTM 240, and DIN 51900) in GOST 21261 for reduction to standard [3] conditions and conversion of the specimen mass to the mass in vacuum. In [23], the first correction for biofuel has been equated to zero. Table 3 gives the experimental values of the upper specific heat of combustion as converted to the dry material together with the published data.…”

“…The method allows one to forecast the viscosity v of synthesized ME on the basis of the fatty-acid compositions of the plant oils with satisfactory accuracy.Quite detailed data have been published on the heats of combustion of plant oils and their esters[2,3,11,23]. However, the discrepancies between the individual values make it difficult to classify them, because the values of the upper heats of combustion of such substances lie in a narrow range: 39-41 MJ/kg.…”