| Summary: | 碩士 === 中原大學 === 化學工程研究所 === 107 === 2-Ethylhexyl nitrate (2-EHN) is an additive for diesel, which can effectively increase the cetane number of diesel. It can improve the combustion performance and reduce the pollution of the exhaust gas by incomplete combustion of diesel. The most common method to produce 2-EHN is using chemical reaction of mixed acid and 2-Ethylhexanol (2-EH). The mixed acid is made from concentrated nitric acid and sulfuric acid. Since the reaction rapidly releases a large amount of heat, the production process is dangerous and not easy to control. Consequently, low production efficiency and safety problem are frequently occured when using a traditional stirred tank as a reactor.
In this study, we use spinning disc reactor (SDR) which is characterized with high heat and mass transfer efficiency, to produce 2-EHN continuously by the nitration of 2-EH. The effect of rotation speed and temperature on the product yield was studied. Additionally, batch system in a stirred tank were carried out at constant temperature, constant feed rate and adiabatic, respectively, for comparison.
Results show that the batch stirred system with constant feed rate has a highest product yield of 91% but only 1.6mL/min production rate at 30℃. And there is a risk that the system loses control when the reaction temperature is too high. In higee system, the optimum yield of 93.4% and production rate of 67.8 mL/min of 2-EHN were obtained when the system temperature was 20 ℃, rotation speed at 1500rpm and total reactant flow rate at 154.1mL/min. The rate of heat removal by SDR was 149.5J/s while that of a batch stirred tank was 4.54J/s. Comparing the two reactors, it was found that the SDR system has a similar product yield, but was significantly better than the batch stirred system in terms of heat removal efficiency and production rate, indicating that SDR has great potential as a reactor for the rapid exothermic chemical reaction.
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