ИССЛЕДОВАНИЕ ПРОЦЕССА ТЕПЛООТДАЧИ ПРИ ГИДРИРОВАНИИ РАСТИТЕЛЬНЫХ МАСЕЛ В СТАЦИОНАРНОМ СЛОЕ КАТАЛИЗАТОРА

Abstract

In this research, we investigated the process of heat transfer from the mixture of cottonseed oil and hydrogen to the reactor wall during a vegetable oil hydrogenation reaction in a fixed-bed catalytic reactor. The dependence of the heat transfer coefficient on the flow rate of the gas-liquid mixture, and consequently, on the mixture feeding regime in the reactor, was established. The elucidation of the heat transfer mechanism during hydrogenation is important for controlling the process concerned. This process is known to occur with a significant thermal effect, which can lead to the overheating of the reactor and undesirable reaction products. The temperature regime determines not only the selectivity and rate of the chemical reaction, but also on the overall performance of the hydrogenation reactor. In this research, the process was studied using cottonseed oil with the addition of 30% hydrogenate and technical hydrogen. Nickel alloy in pellets with a size of 3-5 mm was used as a hydrogenation catalyst. The process was simulated in a reactor, which consisted of a thin-walled heat-insulated copper tube under a continuous heating regime. The temperature of the inner reactor wall was maintained constant at the level of 200 °C. The temperature inside the reactor was monitored using a four-zone thermocouple reader. As a result, dependencies between the heat transfer coefficient and the gas-liquid mixture flow regimes in the reactor have been established. The obtained dependencies provide a better understanding of heat transfer processes occurring in fixed catalyst beds. In order to increase the efficiency of vegetable oil hydrogenation, these dependencies should be taken into account during both the design of hydrogenation reactors and their operation. The calculation of the surface area, where the heat transfer takes place, and the amount of coolant used in the reactor is possible only with the use of these dependencies.