Method for preparing biodiesel by mixing waste edible oil with mineral diesel oil and hydrogenization

Abstract

The invention relates to a method for preparing biodiesel by mixing waste edible oil with mineral diesel oil and hydrogenization. The method comprises the steps as follows: pretreatment of waste edible oil, a first stage of hydrogenization process, a second stage of hydrogenization process, and a product fractionation process. The method adopts the waste edible oil and the mineral diesel oil as raw materials for preparing high-quality biodiesel and biological aviation kerosene components which have low polycyclic aromatic hydrocarbon contents, high cetane values, low sulfur contents and low nitrogen contents, effectively solves the problems of blockage of a catalyst bed caused by the settlement of metal and gelatine in the animal and vegetable hydrogenization process, influence on the activity of catalyst from H2O, CO2 and CO produced in reaction, sulfur supplement of a hydrogenization system, and influence on the service life of the catalyst caused by centralized release of reaction heat, can realize the continuous hydrogenization and industrial production of materials containing animal and vegetable oils, and has practical significance.

Description

technical field [0001] The invention relates to a method for preparing biodiesel by mixing and hydrogenating bio-oil and mineral oil, in particular to a method for preparing biodiesel by mixing and hydrogenating kitchen waste oil and mineral diesel. Background technique [0002] With the rapid development of the economy, my country consumes a lot of petroleum energy, but the reserves of fossil energy are very limited and non-renewable. my country needs to import a large amount of petroleum every year. In addition, the competition for petroleum energy in the world will become more intense in the future. Therefore, the coal seam Methane, geothermal energy, wind energy, solar energy, biomass energy and other renewable or clean energy will be important supplementary energy sources for China's economic development in the future. Among them, biorenewable energy has always been the most important energy research topic because of its source stability and environmental friendliness. ...

AI Technical Summary

Problems solved by technology

The second-generation biodiesel is a pure hydrocarbon and does not contain oxygen. Its cetane number is as high as 70-99, and its calorific value is 44MJ / kg. It has better storage stability, while the cetane number of fatty acid methyl ester Up to 51-56, calorific value up to 37.5MJ / kg, storage stability is not good

[0016] Judging from the properties of animal and vegetable oils or kitchen waste oils and the research results of the hydrogenation process, the obvious deficiency of the above patents is that continuous and industrialized processes are difficult to achieve

Animal and vegetable oils from different sources contain 2-300mg / kg metals and 10-1000mg / kg colloidal substances. In fixed-bed hydrogenation, it will cause coking or fouling of the catalyst bed, block the catalyst bed, and cause catalyst bed The pressure drop rises rapidly, so that the hydrogenation unit cannot operate continuously for a long period; animal and vegetable oils from different sources contain 6-10m% oxygen, and this part of oxygen is partially converted into water during the hydrogenation reaction process, and more water in the reaction product is harmful to the hydrogenation process. The hydrogenation catalyst has a great influence on the activity; animal and vegetable oils generally have low sulfur content, generally less than 10mg / kg, which will cause the sulfur loss of the sulfurized hydrogenation catalyst during use, which will reduce the activity of the catalyst; due to the hydrodecarboxylation of animal and vegetable oils, Hydrogen decarbonylation reaction, there are more than 5m% CO, CO in the vapor phase of the reaction product 2 , if hydrogen cycle is considered, CO, CO in cycle hydrogen 2 higher concentration

Under certain conditions, CO is easy to react with metal Ni, Co, etc. in the hydrogenation catalyst to form nickel carbonyl (cobalt), which poisons the catalyst and loses its activity; the hydrogenation process of animal and vegetable oils is accompanied by a large amount of reaction heat, and the reaction heat Concentrating on the upper bed of the catalyst will cause the upper catalyst to lose its activity in a short period of time

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