Method for removing organic chlorine in oil product

Abstract

The invention provides a method for removing organochlorine in an oil product, belongs to the technical field of petroleum processing, and particularly relates to a method for removing organochlorine in an oil product. The method comprises the following steps: mixing a phase transfer catalyst, a nucleophilic reagent, a demulsifier, deionized water and an oil product, carrying out a reflux stirring reaction at 80-120 DEG C for 0.5-2 h, cooling, standing, and carrying out oil-water separation to obtain a dechlorinated oil product. The phase transfer catalyst is added into the reaction system, so that the oil phase and the water phase are in full contact, the reaction rate is increased, and a better dechlorination effect is achieved. The method is convenient to operate and simple in process, the chlorine content in the oil product can be obviously reduced, meanwhile, the components of the oil product cannot be changed, and the problems of equipment corrosion, catalyst poisoning, ammonium salt blockage and the like of an oil refinery are effectively solved.

Description

Technical Field

[0001] The invention belongs to the technical field of petroleum processing, and in particular relates to a method for removing organic chlorine from oil products. Background Art

[0002] There are two types of chlorine in crude oil: inorganic chloride and organic chloride. Inorganic chloride often exists in the form of salt with alkali metals and alkaline earth metals, distributed in a small amount of water contained in crude oil, or distributed in the crude oil in the form of crystals. There are two main sources of organic chloride: one is the natural chloride contained in the crude oil itself, and the other is the chlorine-containing additives added later during oil production and refining. In recent years, with the increase in the depth of oil field exploitation, the various oil production additives used in the oil production process have also increased significantly. These additives often contain a certain amount of organic chlorine. The desalting agents, oil pipelines and oil tank cleaning agents used in the oil refining process also contain organic chlorides. The use of these additives increases the organic chlorine content in crude oil. These chlorides will cause great harm in the production and processing of oil refining, mainly manifested as equipment corrosion, pipeline blockage and catalyst poisoning. In the catalytic reforming unit, chlorine will also destroy the water / chlorine balance of the catalyst, causing the product quality to decline. Therefore, it is necessary to remove the chlorides in oil products.

[0003] At present, the removal technology of inorganic chlorine is relatively mature. The electro-desalting process can remove most of the inorganic chlorine, but it has almost no effect on the removal of organic chlorine. The main methods for removing organic chlorine are catalytic hydrogenation, adsorption and phase transfer nucleophilic substitution. The catalytic hydrogenation method is relatively mature, but the method is costly, the reaction conditions are harsh, and metals or metal ions will be introduced into crude oil, which will lead to problems such as excessive metal content in crude oil, affecting the subsequent refining process. Therefore, this method is difficult to apply to the actual dechlorination of crude oil. The adsorption method removes organic chlorides, which has high requirements for adsorbents. The adsorbent can not only adsorb polar organic chlorides, but also adsorb non-polar organic chlorides, and it is also required to have a large adsorption capacity. In addition, the adsorbent needs to be regenerative to meet the requirements of recycling. The phase transfer nucleophilic substitution method for removing organic chlorine has the advantages of high catalytic activity and high reaction efficiency, and can solve the problem of insufficient contact between the oil and water phases. The difficulty is to screen and develop phase transfer catalysts with low price, simple preparation, mild conditions and high chlorine removal rate.

[0004] The Chinese patent document with publication number CN101851528A discloses a method for removing inorganic chlorine and organic chlorine from hydrocarbon oil, using organic amine and inorganic base as desalting aids for dechlorination, but the method has a low organic chlorine removal rate, which can only reach 89% at most.

[0005] The Chinese patent document with publication number CN117431087A discloses a method for removing organic chlorine from oil products, which uses an inorganic base or an organic base as a nucleophilic reagent to remove organic chlorine in an organic solvent such as dimethyl sulfoxide or an organic amine. This method can remove most of the chlorine, but the amount of organic solvent used is large, the cost is high, and the toxicity is high. In addition, the organic amine has a certain oil solubility, which will increase the nitrogen content in the oil products. Summary of the invention

[0006] The purpose of the present invention is to provide a method for removing organic chlorine from oil products. The method accelerates the reaction between the oil and water phases and improves the reaction rate by adding a phase transfer catalyst into the reaction system, thereby effectively removing organic chlorine from the oil products. The reaction conditions are mild, the cost is low, and the composition of the oil products will not be changed.

[0007] The present invention provides a technical solution for removing organic chlorine from oil products: The phase transfer catalyst, nucleophilic reagent, demulsifier, deionized water and oil are mixed, and refluxed and stirred at 80-120°C for 0.5-2h. After cooling and standing, the oil and water are separated to obtain the dechlorinated oil.

[0008] Furthermore, the oil product is one of crude oil and waste lubricating oil.

[0009] Furthermore, the phase transfer catalyst is one of tetrapropylammonium hydroxide, pyridine, polyethylene glycol dialkyl ether, dodecyltrimethylammonium bromide, tetradecyltrimethylammonium bromide, and hexadecyltrimethylammonium bromide.

[0010] Furthermore, the nucleophilic agent is one of sodium phosphate, potassium phosphate and sodium sulfite.

[0011] Furthermore, the demulsifier is one of AP type and SP type demulsifiers.

[0012] Furthermore, the amount of phase transfer catalyst used is 40-100 times the amount of organic chlorine in the oil product.

[0013] Furthermore, the amount of the nucleophilic agent used is 100-500 times the amount of organic chlorine in the oil product.

[0014] Furthermore, the amount of demulsifier used is 0.1-0.5% by weight of the oil product.

[0015] Furthermore, the mass ratio of deionized water to oil is 1:2-4.

[0016] The invention has the following beneficial effects: the invention selects tetrapropylammonium hydroxide, polyethylene glycol dialkyl ether, dodecyltrimethylammonium bromide, tetradecyltrimethylammonium bromide, hexadecyltrimethylammonium bromide and the like as phase transfer catalysts, which have good solubility and alkalinity, and have a hydrophobic long chain and a hydrophilic or ion-dissociable group, so that the oil and water phases can be fully contacted, and the organic chlorine molecules are transferred from the oil phase to the water phase, and then undergo a substitution reaction with a nucleophilic reagent to generate water-soluble inorganic chlorine ions that are removed. At the same time, the reaction conditions are mild, the operation is simple, the catalytic reaction can be carried out at a relatively mild temperature and pressure, and high temperature conditions are avoided, and no complicated operating procedures or expensive special solvents are required, thereby simplifying the process.

[0017] The phase transfer catalyst used in the present invention effectively reduces the interfacial tension between the oil and water phases, enables the organic chlorine to fully contact with the nucleophilic reagent, accelerates the reaction between the oil and water phases, increases the reaction rate, has a good dechlorination effect, and the dechlorination rate can reach 98.80%.

[0018] The reaction conditions of the invention are mild and the process operation is simple. The mixing and stirring reaction is carried out at 80-120° C., and then the oil-water separation is carried out. The adopted nucleophilic reagent is cheap and easy to obtain, and the cost of using water as a solvent is low. The dechlorination process does not introduce new impurities and does not change the component composition of the oil product. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention is clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Example 1

[0020] The chlorine content of the waste lubricating oil used is 668 mg / L. Tetrapropylammonium hydroxide is selected as a phase transfer catalyst, and the amount added is 40 times the organic chlorine content in the waste lubricating oil. Sodium phosphate is a nucleophilic reagent, and the amount added is 200 times the organic chlorine content in the waste lubricating oil. 0.1g of AP type demulsifier is mixed and stirred and dissolved in 25g of deionized water. After complete dissolution, it is added to 100g of waste lubricating oil. After mixing, pour it into a 250mL three-necked flask, heat and reflux at 80℃ and stir to react for 1h. After the reaction is completed, the reaction product is moved to a separating funnel and allowed to stand for stratification to obtain the upper oil phase. The chlorine content in the oil phase is measured to be 18mg / L, and the dechlorination rate is 97.31%. Example 2

[0021] The chlorine content of the waste lubricating oil used is 668 mg / L. Polyethylene glycol dialkyl ether is selected as a phase transfer catalyst, and the amount added is 80 times the organic chlorine content in the waste lubricating oil. Sodium phosphate is a nucleophilic reagent, and the amount added is 300 times the organic chlorine content in the waste lubricating oil. 0.3g of AP type demulsifier is mixed and stirred and dissolved in 50g of deionized water. After complete dissolution, it is added to 100g of waste lubricating oil. After mixing, pour it into a 250mL three-necked flask, heat and reflux at 100℃ and stir to react for 1.5h. After the reaction is completed, the reaction product is moved to a separating funnel and allowed to stand for stratification to obtain the upper oil phase. The chlorine content in the oil phase is measured to be 23mg / L, and the dechlorination rate is 96.56%. Example 3

[0022] The chlorine content of the waste lubricating oil used is 668 mg / L. Pyridine is selected as a phase transfer catalyst, and the amount added is 100 times the organic chlorine content in the waste lubricating oil. Potassium phosphate is a nucleophilic reagent, and the amount added is 400 times the organic chlorine content in the waste lubricating oil. 0.2g of SP type demulsifier is mixed and stirred and dissolved in 50g of deionized water. After complete dissolution, it is added to 100g of waste lubricating oil. After mixing, pour it into a 250mL three-necked flask, heat and reflux at 120℃ and stir to react for 2h. After the reaction is completed, the reaction product is transferred to a separating funnel and allowed to stand for stratification to obtain the upper oil phase. The chlorine content in the oil phase is measured to be 13mg / L, and the dechlorination rate is 98.05%. Example 4

[0023] The chlorine content of the crude oil used was 168 mg / L. Dodecyl trimethyl ammonium bromide was selected as a phase transfer catalyst, and the amount added was 60 times the organic chlorine content in the crude oil. Potassium phosphate was used as a nucleophilic reagent, and the amount added was 500 times the organic chlorine content in the crude oil. 0.3g of SP type demulsifier was mixed and stirred and dissolved in 33g of deionized water. After complete dissolution, it was added to 100g of crude oil. After mixing, it was poured into a 500mL three-necked flask, heated under reflux and stirred at 110°C for 1.5h. After the reaction was completed, the reaction product was transferred to a separating funnel and allowed to stand for stratification to obtain an upper oil phase. The chlorine content in the oil phase was determined to be 5mg / L, and the dechlorination rate was 97.02%. Example 5

[0024] The chlorine content of the crude oil used was 168 mg / L. Hexadecyl trimethyl ammonium bromide was selected as a phase transfer catalyst, and the amount added was 40 times the organic chlorine content in the crude oil. Sodium sulfite was used as a nucleophilic reagent, and the amount added was 100 times the organic chlorine content in the crude oil. 0.4 g of AP type demulsifier was mixed and stirred and dissolved in 25 g of deionized water. After complete dissolution, it was added to 100 g of crude oil. After mixing, it was poured into a 250 mL three-necked flask, heated under reflux at 90 ° C and stirred for 0.5 h. After the reaction was completed, the reaction product was transferred to a separating funnel and allowed to stand for stratification to obtain an upper oil phase. The chlorine content in the oil phase was measured to be 8 mg / L, and the dechlorination rate was 95.24%. Example 6

[0025] The chlorine content of the crude oil used was 168 mg / L. Tetradecyl trimethyl ammonium bromide was selected as a phase transfer catalyst, and the amount added was 100 times the organic chlorine content in the crude oil. Sodium phosphate was used as a nucleophilic reagent, and the amount added was 500 times the organic chlorine content in the crude oil. 0.3 g of SP type demulsifier was mixed and stirred and dissolved in 50 g of deionized water. After complete dissolution, it was added to 100 g of crude oil. After mixing, it was poured into a 250 mL three-necked flask, heated under reflux and stirred at 100 ° C for 2 hours. After the reaction was completed, the reaction product was transferred to a separating funnel and allowed to stand for stratification to obtain an upper oil phase. The chlorine content in the oil phase was determined to be 10 mg / L, and the dechlorination rate was 94.05%. Example 7

[0026] The chlorine content of the waste lubricating oil used is 668 mg / L. Tetrapropylammonium hydroxide is selected as a phase transfer catalyst, and the amount added is 80 times the organic chlorine content in the waste lubricating oil. Sodium sulfite is a nucleophilic reagent, and the amount added is 400 times the organic chlorine content in the waste lubricating oil. 0.5g of SP type demulsifier is mixed and stirred and dissolved in 33g of deionized water. After complete dissolution, it is added to 100g of waste lubricating oil. After mixing, pour it into a 250mL three-necked flask, heat and reflux at 120℃ and stir to react for 2h. After the reaction is completed, the reaction product is moved to a separating funnel and allowed to stand for stratification to obtain the upper oil phase. The chlorine content in the oil phase is measured to be 8mg / L, and the dechlorination rate is 98.80%.

[0027] The above is an exemplary description of the embodiments of the present invention. However, the protection scope of the present invention is not limited to the above embodiments. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made on the basis of the above description, and the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. A method for removing organic chlorine from oil products, characterized in that: The phase transfer catalyst, nucleophilic reagent, demulsifier, deionized water and oil are mixed, and refluxed and stirred at 80-120°C for 0.5-2h. After cooling and standing, the oil and water are separated to obtain the dechlorinated oil.

2. The method for removing organic chlorine from oil products according to claim 1, characterized in that: The oil product is one of crude oil and waste lubricating oil.

3. The method for removing organic chlorine from oil products according to claim 1, characterized in that: The phase transfer catalyst is one of tetrapropylammonium hydroxide, pyridine, polyethylene glycol dialkyl ether, dodecyltrimethylammonium bromide, tetradecyltrimethylammonium bromide and hexadecyltrimethylammonium bromide.

4. The method for removing organic chlorine from oil products according to claim 1, characterized in that: The nucleophilic reagent is one of sodium phosphate, potassium phosphate and sodium sulfite.

5. The method for removing organic chlorine from oil products according to claim 1, characterized in that: The demulsifier is one of AP type and SP type demulsifier.

6. The method for removing organic chlorine from oil products according to claim 1, characterized in that: The amount of the phase transfer catalyst used is 40-100 times the amount of organic chlorine in the oil product.

7. The method for removing organic chlorine from oil products according to claim 1, characterized in that: The amount of the nucleophilic agent used is 100-500 times the content of organic chlorine in the oil product.

8. The method for removing organic chlorine from oil products according to claim 1, characterized in that: The demulsifier is used in an amount of 0.1-0.5% by weight of the oil product.

9. The method for removing organic chlorine from oil products according to claim 1, characterized in that: The mass ratio of the deionized water to the oil product is 1:2-4.