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CN-122012178-A - Method for removing impurities through grease reaction separation

CN122012178ACN 122012178 ACN122012178 ACN 122012178ACN-122012178-A

Abstract

The invention provides a method for removing impurities through grease reaction separation, which comprises the steps of heating a grease raw material in the presence of a polar medium, enabling the grease raw material to fully react under the action of an alkaline catalyst, and then separating the polar medium in a mixture obtained after the reaction to obtain pretreated grease, wherein the polar medium comprises one or a combination of a C1-C6 monohydric alcohol and carbonic ester thereof. The method provided by the invention has the advantages of strong adaptability of the oil raw materials, capability of directly processing various oil raw materials, short process flow of oil reaction separation technology, low material consumption, high recycling rate of the oil raw materials, low impurity content of the obtained refined oil and high quality.

Inventors

  • ZHANG JIAREN
  • LI JIN
  • WANG MINHUI
  • HE HAO

Assignees

  • 中国石油天然气股份有限公司

Dates

Publication Date
20260512
Application Date
20241112

Claims (13)

  1. 1. The method for removing impurities by grease reaction separation is characterized by comprising the steps of heating a grease raw material in the presence of a polar medium, fully reacting the grease raw material under the action of an alkaline catalyst, and removing the polar medium in a mixture obtained after the reaction to obtain pretreated grease; Wherein the polar medium comprises one or a combination of several of monohydric alcohol of C1 to C6 and carbonic ester thereof.
  2. 2. The method of claim 1, wherein the polar medium comprises one or a combination of methanol, ethanol, propanol, isopropanol, butanol, isobutanol, pentanol and hexanol and carbonates thereof.
  3. 3. The method according to claim 1 or 2, further comprising mixing a polyol and/or water into the polar medium.
  4. 4. The method of claim 3, wherein the polyol comprises one or a combination of several of ethylene glycol, glycerol, polyglycerol with a molecular weight of less than 800, pentose alcohol, and sorbitol.
  5. 5. A method according to claim 3, characterized in that the amount of polyol and/or water is not more than 100wt%, based on 100% total weight of the fat raw material.
  6. 6. The method according to claim 1 or 2, wherein the fat and oil raw material comprises one or a combination of several of animal fat and oil raw materials, animal fat and oil, vegetable fat and oil and waste fat and oil.
  7. 7. The method of claim 1, wherein the basic catalyst comprises one or a combination of several of oxides, hydroxides, carbonates and bicarbonates of sodium, potassium, magnesium, calcium, zinc and aluminum.
  8. 8. The method according to claim 1 or 7, wherein the amount of the alkaline catalyst is less than 1wt% of the grease mass.
  9. 9. The method of claim 1, wherein the mass ratio of the grease to the polar medium is 1:0.2-1:2.
  10. 10. The process according to claim 1 or 9, wherein the reaction is carried out at a temperature of 120-360 ℃, a pressure of 0.5-25MPa and a reaction time of 0.5-4h.
  11. 11. The method according to claim 1 or 9, characterized in that the reaction is a continuous reaction or a batch reaction and/or the reaction is a single reaction or a plurality of reactions.
  12. 12. The method of claim 1 or 2, wherein the separating comprises distillation, sedimentation or centrifugation.
  13. 13. The method according to claim 1 or 2, further comprising subjecting the pretreated fat to reduced pressure distillation and/or adsorption treatment to obtain a high quality refined oil.

Description

Method for removing impurities through grease reaction separation Technical Field The invention relates to a method for removing impurities through grease reaction separation, and belongs to the technical field of biomass energy, in particular to the technical field of grease refining separation. Background The long-term use of fossil resources for the production of liquid fuels in large quantities has had a negative impact on the environment, such as greenhouse effect. And reserves of these non-renewable resources decrease year by year as they continue to consume. Biofuel is a low-carbon, clean, green and renewable fuel that has evolved into an important complement to petrochemical diesel with increasing emphasis on environmental and health concerns. The biological liquid fuel (such as hydrocarbon biodiesel, biological aviation kerosene and the like) prepared by hydrodeoxygenation isomerization of the grease has the excellent characteristics of high heat value, good combustion performance, similar composition with petrochemical fuel, good compatibility and the like, and is widely valued. Accordingly, research into the technology of preparing liquid fuels by hydrodeoxygenation of fats and oils has been increasingly paid attention to in the art. The oil raw material is accompanied by various impurities such as phospholipids, sulfur, chlorine, nitrogen, metals, and the like. Impurities in the grease can accelerate the problems of inactivation of hydrodeoxygenation catalyst, corrosion of the reactor and the like, so that the reactor cannot normally and stably run, and even the safety risk is increased. Therefore, the grease is fully refined and separated, and the high-quality refined oil is obtained, which is the key for ensuring the stable operation of the device for preparing the biofuel from the grease. Currently, edible vegetable oil refining processes are widely used. The oil refining technology with edible oil as target mainly includes the key units of squeezing, extracting, degumming, deacidifying, dewatering, decolorizing, deodorizing, dewaxing, etc. For example, the vegetable oil refining technology can refine jatropha curcas oil, palm oil, cottonseed oil, castor oil and the like to obtain refined oil with higher quality. However, the oil refining technology has higher material consumption, large solid waste amount, poor raw material adaptability and large fatty acid loss for recycling oil in catering industry with higher acid value. In energy utilization, the vegetable oil refining process requires that the free fatty acid content of crude oil is less than 15wt%, the sulfur content is less than 30mg/kg, and the chlorine content is less than 8mg/kg, and the edible oil refining process generally requires that the crude oil acid value is less than 10mgKOH/g. More importantly, the refining process technology of edible vegetable oil has extremely poor separation effect on chlorine, sulfur and other impurities in poor-quality oil raw materials such as reclaimed oil in the catering industry, and refined oil meeting the hydrogenation reaction requirement cannot be obtained generally. Therefore, the grease raw materials for preparing the hydrocarbon biodiesel and the biological aviation kerosene are mainly refined vegetable grease or part of catering industry recovered grease with higher quality grade. The recovered grease in the catering industry with a large amount of low cost is difficult to refine and remove impurities because of complex and changeable impurity composition, and cannot be used for hydrodeoxygenation to realize energy utilization. In addition, there is a significant difference in the requirements of oil refining, which are aimed at energy applications and at eating. For eating, phospholipids, vitamin E, sterols and the like in the oil are beneficial components, and free fatty acids and trans fatty acids need to be limited, while for energy application, free fatty acids are still important raw materials, and other components need to be limited. Poor-quality oil raw materials such as reclaimed oil in the catering industry are high in acid value and even exceed 120mgKOH/g, and free fatty acid raw materials are required to be fully utilized. The waste grease raw materials such as reclaimed oil in catering industry are generally low in price, high in acid value and various in impurity types and contents, particularly sulfur, chlorine, phosphorus, nitrogen, metal and other impurities (the contents can reach 500mg/kg, 160mg/kg, 1wt%, 400mg/kg and 800mg/kg respectively), and the technical difficulty of refining the waste grease is obviously increased. CN117431087a discloses a method for removing organic chlorine in oil products, which aims at plastic pyrolysis oil, waste grease of catering, crude oil and distillate oil thereof, and the like, wherein the oil products, nucleophile (potassium hydroxide, sodium ethoxide and the like) and solvent (ethylene glycol, glycerol, ethanolamine and the like) ar