Study On Distillation Of Oleoresin And Design Of Process Equipment By Circulating Gas Method With Carbon Dioxide

This paper summarized the origin of oleoresin,the development of rosin production both in domestic and overseas.Then it compared the vitues and weaknesses of different oleoresin distillation methods.The traditional steam distillation of oleoresin has a long technical process and consumes high energy,which wastes a lot quantity of heat for phase transformation used as circulating gas.Moreover in order to carry off the heat of steam which comes out from oleoresin distiller,it also needs the massive cooling water.At the same time, the quality of these products including rosin,turpentine is lowered because of residual trace water.On the other hand,the eligible turpentine can not be produced without filting for salt, especially when the water proportion in the rosin is more than 0.15 percent,crystallanity will happen seriously.To resolve these series problems,it has significal meaning both in scientific theory and in reality production in researching the distillation techniques of oleoresin deeply.Distillation of oleoresin with Claisen flask as distiller and CO₂ as circulating gas was studied in this paper.Factors such as flow capacity of circulating gas,distillation pressure, end distillation temperature,temperature of circulating gas,and kinds of gas which influence the distillation of oleoresin were investigated.The results showed that optimum technological conditions of distillation of oleoresin for producing 1 kg rosin were as follows:flow rate of CO₂ 0.140-0.160 m³/h,distillation pressure 12.67 kPa,end temperature of distillation 185-190℃.The effects of temperature and kinds of circulating gas on distillation of oleoresin were insignificant.Since boiling point and content of distillate components were different, operation sequences of flow rate of CO₂ from 0.100 to 0.160 m³/h and distillation temperature from 80 to 185℃were preferable. According to the experimental results,the technology and process equipment of distillation of oleoresin by circulating gas method with carbon dioxide have been calculated and production workshop of an annual output of 10,000 tons distillation of oleoresin by circulating gas method with carbon dioxide.The materials balance and heat balance of melting,clarification and distillation processes were calculated,and the comparison of distillation of oleoresin between the direct steam method and CO₂ circulating gas method in energy consumption,process equipment,product quality and industrial emissions was discussed.The results show that the method of CO₂ circulating gas distillation consuming less energy than the direct steam method.Since no phase transformation occurs during circulating gas distillation,heat for phase transformation of overheated steam in traditional process has been saved.Compared with direct steam method,the consumption of energy and cooling water by this method were decreased by 1.663～2.034 GJ and 7.986～9.762 m³ respectively. Separator for oil from water,filter for salt and large boiler for producing overheated steam were not required.Water was not contained in products manufactured by this method.The rosin showed no crystallanity,and turpentine was transparent without turbidity.At the exit of mixture of carbon dioxide and turpentine,water ring vaccum pump was used to carry out separation,meanwhile carbon dioxide was reused again,which could resolve the excessive cost when using inert gas.It showed that the technology of distillation of oleoresin by circulating gas method with carbon dioxide is a clean process without emission of three wastes.