Experimental And Theoretical Study On Isobaric Heat Capacity Of Biodiesel Based On The Principle Of Contrasting State

Biodiesel,which is clean and renewable energy with a wide range of raw materials,is one of the alternatives to traditional fossil energy.Specific heat capacity is one of the key thermophysical properties of fluids,and it is the basic data in the calculation of heat transfer and flow,the design of heat engines,and the production process of working fluids.Fatty acid methyl ester and fatty acid ethyl ester are the main components of biodiesel.At present,domestic and foreign scholars have carried out some experimental studies on the specific heat capacity of a variety of fatty acid esters,the measurement was conducted at temperature under 400 K and pressure at atmosphere.Even more there is no experimental data on the specific heat capacity of some fatty acid esters.Therefore,the specific heat capacity of a lot of fatty acid esters was experimentally studied by flow calorimetry.Based on the principle of corresponding states,the fatty acid lipids were studied theoretically,and their theoretical calculation models were constructed.1.A flow calorimetry is used to measure the specific pressure heat capacity of the fluid,the temperature range is 293～453 K,and the pressure can reach 10 MPa.The specific heat capacity of water is measured.Compared with the literature,the maximum absolute deviation is 0.38%,and the average absolute deviation is 0.12%,which verified the reliability of the experimental system.2.The specific heat capacity of methyl octanoate,ethyl octanoate,methyl myristate,and ethyl myristate,with a temperature range of 313～453 K and a pressure range of 0.1～10 MPa,are measured,most of c_p for the sample are obtained for the first time,and the calculation equations for the specific heat capacity are fitted according to the experimental data,and the maximum absolute deviation between the calculation and the experimental value was:1.99%,1.85%,1.42%,1.27%respectively;the absolute average deviations were 0.48%,0.48%,0.50%and 0.50%,respectively.The calculation equation provided a basis the specific constant heat capacity above substances.3.Based on the principle of contrast state and cofunction,a theoretical calculation model of the heat capacity of fatty acid esters is proposed,and the maximum absolute deviation from the experimental measurement value is 1.65%,and the absolute average deviation is 0.3%,which provided a reference for calculation the heat capacity of biodiesel.