Study On The Key Technical Problems In The Preparation Of Biodiesel From Glyceride Ester

Biodiesel is an important green energy and oil chemical raw material,which can be used in the production of bio-based plasticizer,lubricating oil and other high value-added products.In recent years,the process of preparing biodiesel by glyceride esterification has avoided the problems of equipment corrosion,sulfuric acid waste water,incomplete acid reduction,etc,and has the advantages of low requirement of raw materials and high yield of products,so it has a good application prospect.However,there are still some key technical problems to be solved in this method,including the treatment of glycerol asphalt,the recovery of steam heat from glycerol wastewater,the treatment of glycerol esterification wastewater,and the coking of materials in the process of glycerol esterification,etc..Therefore,this article mainly aims at "treatment of glycerine pitch" and "heat recovery of glycerin wastewater steam" the two key technical problems,the research on the resource utilization of glycerol asphalt and the fractional condensation of glycerol wastewater was carried out,in order to develop a new technology of resource utilization of glycerine asphalt,at the same time to design a new scheme for steam heat efficient recovery of glycerin wastewater.The main research contents and conclusions are as follows:(1)In the research process of resource utilization of glycerol asphalt,the composition of glycerol asphalt was firstly analyzed,and the results showed that glycerol asphalt contained a large amount of methyl ester,saponification,glycerol and other components.Then,the acidification process of glycerol asphalt was studied by sulfuric acid acidification method,by acidification oil yield optimization index,theeffects of sulfuric acid dosage,water dosage,reaction temperature and reaction time on acidification were investigated,the orthogonal experiment results showed that the better experimental conditions for sulfuric acid acidification reaction of glycerol pitch were sulfuric acid dosage of 15 wt%,water dosage of 30 wt%,reaction temperature of60 ℃ and reaction time of 1.5 h.Then,under the above conditions,the influence of the number of sulfuric acid application on recovery of acidified oil,sylvite and glycerin after glycerol asphalting was further investigated,in the process of continuous application of sulfuric acid water six times,the results showed that the application times had almost no effect on the yield and quality of the acidified oil,and the yield of the acidified oil was more than 84%,the acidified oil could be further used in the process of preparing biodiesel,and the yield of biodiesel was about60%;The increase of application times is beneficial to the recovery of sylvite and glycerin.Potassium salt and recovered glycerin can be obtained by neutralization,filtration,dehydration and distillation of sulfuric acid water after application.Finally,the potential advantages and economic benefits of treating glycerine asphalt with sulfuric acid water for six consecutive times are analyzed.The results show that the treatment of 10,000 tons of glycerine asphalt per year can save about 600 tons of sulfuric acid and 2,200 tons of water per year.At the same time,8,770 tons of acidified oil,1,440 tons of crude potash salt and 290 tons of crude glycerin can be recovered,generating economic benefits of about 35.8 million yuan.(2)During the study of fractional condensation of glycerin wastewater vapor,the influence of primary condensing temperature on the quality distribution of materials in the reactor,primary condensing recycled materials and secondary condensing recycled materials was investigated.The results show that the temperature of primary condensation has no obvious effect on the quality of materials in the reactor,primary condensation recovery material and secondary condensation recovery material.And the sum of the three masses is consistent.The primary condensation recovery material is mainly glycerin and grease,with the content of glycerin about 80% and the content of grease about 10%.The higher the primary condensation temperature is,the lower the water content is,but the content of glycerin and grease is basically unchanged.For secondary condensing recycled materials,the main component is water with a content of about 99%.The higher the primary condensing temperature is,the higher the glycerin content will be.When the primary condensing temperature reaches 160 ℃,the glycerin content will exceed 1%,and the better primary condensing temperature is150 ℃.On this basis,the steam heat recovery process of glycerin wastewater wascompared with that of the fractional condensation process and the single-stage condensation process.The results show that the fractional condensation process can significantly reduce the energy consumption and at the first-order condensation temperature of 150 ℃,the recovery of glycerin was completed while heat recovery was realized,and glycerin could be used to prepare biodiesel;Compared with the single-stage condensation process,the fractional condensation process is applied to the biodiesel production process with an annual output of 100,000 tons,saving 3,200 tons of steam and 100,000,0 tons of cooling water annually,and producing about4,700 tons of waste water steam as a by-product.Its economic benefits are considerable.