Hydrodeoxygenation process for biodiesel

Abstract

The invention discloses a hydrodeoxygenation process for biodiesel. The hydrodeoxygenation process is characterized in that a fixed bed reactor filled with a hydrodeoxygenation catalyst is adopted, and the hydrodeoxygenation catalyst comprises a carrier and an active component; the carrier is SAPO-5 doped with a heteroatom Cu<2+> in a synthetic skeleton structure; the active component is a mixture of dimolybdenum nitride Mo2N, tungsten nitride W2N, molybdenum carbide Mo2C and tungsten carbide WC; the catalyst further contains a catalysis aid which is a mixture of TiO2, CeO2, V2O5 and NbOPO4; and the reaction conditions of the fixed bed reactor are as follows: the reaction temperature is 300-450 DEG C, the hydrogen pressure is 2.5MPa-3.5MPa, the volume ratio of hydrogen to oil is 500 to 800, and the volume space velocity is 1.0h<-1>-2.5h<-1>. According to the hydrodeoxygenation process, the hydrodeoxygenation of the biodiesel can be maintained at a relatively high deoxidizing ratio (99.8% or above), and the catalytic activity is not obviously decreased after the continuous working for 500 hours.

Description

technical field [0001] The invention relates to biodiesel hydrodeoxygenation process. Background technique [0002] In the 21st century, the demand and use of fuel oil have increased significantly, and the environmental pollution caused by sulfur compounds in it has attracted people's attention. Sulfur oxides (SO x ) into the air, producing acid rain and sulfuric acid smog pollution, etc., resulting in air pollution. [0003] In order to solve the increasingly serious environmental problems and reduce the environmental pollution caused by fossil fuels, it has recently become a hot spot to use vegetable oil as the basis and make full use of renewable resources as fuel. [0004] In the 1980s, American Graham Quick introduced linseed oil and cottonseed oleate methyl ester into diesel engines for the first time. After that, he defined fatty acid monoester compounds obtained through transesterification as biodiesel. This fatty acid monoester compound can be used alone or mixed...

AI Technical Summary

Problems solved by technology

However, with the wide application of biodiesel, more and more defects are found: animal and vegetable oils and fats contain different types of fatty acids, and the production process will not change the degree of unsaturation, which is high, such as Biodiesel produced from cottonseed oil, rapeseed oil, etc., contains a large number of carbon-carbon unsaturated bonds in the molecular structure, which is easy to oxidize and cause deterioration during storage, transportation and use. If the unsaturation is low, such as industrial lard and tallow The freezing point of the biodiesel produced by biodiesel is much higher than that of petrochemical diesel. Even if it is mixed with petrochemical diesel in a lower proportion, it is easy to precipitate in low temperature seasons such as autumn and winter, resulting in pipeline blockage, and even damage to the engine in severe cases.

Despite a lot of research and improvements, the molecular structure of biodiesel has not changed, so its defects still exist