Method for preparing biodiesel from oil with high acid value

Abstract

The invention discloses a method for preparing biodiesel from oil with a high acid value. The method comprises the steps as follows: mixing oil with a high acid value with methanol, adding compound acid catalyst, carrying out esterification reaction, removing crude methanol through flash vaporization, adding potassium hydroxide methanol solution, performing transesterification reaction, removing crude methanol through flash vaporization again, standing liquid from which crude methanol is removed and settling for 4 to 5 hours, and removing glycerol through separation to obtain crude biodiesel.The method has the characteristics of low device investment, simple process, low manufacturing cost, high reaction rate and high conversion rate of products.

Description

technical field [0001] The invention belongs to the technical field of energy production methods, in particular to a method for preparing biodiesel from oil with high acid value. Background technique [0002] As we all know, the energy problem is the primary problem of economic development, and it is the bottleneck that restricts economic and social development for a long time. However, China's oil resources are poor, and about 55% of oil depends on imports. In 2011, the national annual demand for diesel oil was about 1,138.8 million barrels , the development of biodiesel that can replace petrochemical diesel has become a top priority. The use of waste animal and vegetable oils, etc. The processing and use of biodiesel is a very important strategy for promoting energy substitution, reducing the emission of harmful substances such as carbon, sulfur, hydrocarbons, carcinogenic aromatic hydrocarbons, and waste particulates, protecting the atmospheric environment, maintaining en...

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Problems solved by technology

[0002] As we all know, the energy problem is the primary problem of economic development, and it is the bottleneck that restricts economic and social development for a long time. However, China's oil resources are poor, and about 55% of oil depends on imports. In 2011, the national annual demand for diesel oil was about 1,138.8 million barrels , the development of biodiesel that can replace petrochemical diesel has become a top priority. The use of waste animal and vegetable oils, etc. The processing and use of biodiesel is a very important strategy for promoting energy substitution, reducing the emission of harmful substances such as carbon, sulfur, hydrocarbons, carcinogenic aromatic hydrocarbons, and waste particulates, protecting the atmospheric environment, maintaining energy security and ecological environment governance Significance; With the increasing depletion of oil resources worldwide and the improvement of people's awareness of environmental protection, the enthusiasm for biodiesel research and development in countries around the world has been increased. In foreign countries, genetically modified vegetable oil is mostly used as raw material, and the cost is high. There is a competition for oil with humans and animals. It is not suitable for China's national conditions; domestic manufacturers mostly use waste animal and vegetable oils such as waste oil, acidified oil, hog oil, and fatty acids as raw materials to produce biodiesel. greater than 150°C), or supercritical process (temperature greater than 300°C), complex process, large equipment investment, high cost, intermittent production, manual control, low production efficiency, waste acid water discharge during production, post-treatment is required; product quality Unstable, unable to meet the requirements of industrialization