Method for removing organic chlorine from crude oil by using micro-reaction equipment

Abstract

This invention relates to the field of crude oil dechlorination technology, and provides a method for removing organochlorine from crude oil using a microreactor. The method includes passing crude oil and dechlorination components into a microreactor for mixing, allowing a dechlorination reaction to occur, and then separating the crude oil and dechlorination components. The dechlorination components include a phase transfer agent, a nucleophile, and a solvent. Compared with existing batch dechlorination reaction technology, the method for removing organochlorine from crude oil using a microreactor provided by this invention can effectively reduce the mass transfer resistance of the dechlorination reaction, improve the reaction efficiency, and significantly increase the removal rate of organochlorine by more than 100%. Furthermore, it can be operated continuously; the entire process is closed-loop, ensuring high safety, and the equipment is relatively small, showing broad prospects for practical industrial applications.

Description

Technical Field

[0001] This invention relates to the field of crude oil dechlorination technology, and more specifically, to a method for removing organochlorine from crude oil using a microreactor. Background Technology

[0002] In recent years, several production and product quality incidents have occurred in China due to excessive levels of organochlorides in crude oil / distillate oils. In particular, in May 2013, the abnormally high chlorine content in Shengli crude oil severely impacted the normal production of several refineries in North China and along the Yangtze River. Furthermore, the combustion of organochlorides in oil products poses a potential threat to environmental quality. Therefore, reducing the organochloride content in oil products is of paramount importance.

[0003] Organochlorinated compounds in crude oil mainly come from two sources: naturally occurring organochlorinated compounds present in the crude oil itself, and chlorinated chemical additives added artificially during crude oil extraction, transportation, and processing. Organochlorinated compounds in crude oil generally include monochloropropane, dichloroethane, trichloromethane, dichloromethane, carbon tetrachloride, and epichlorohydrin, etc., and the types of organochlorinated compounds contained in crude oil from different oil fields will vary. Organochlorinated compounds in crude oil distillate fractions are mainly concentrated in naphtha fractions. In distillation units, organochlorinated compounds undergo hydrolysis, and the generated HCl reacts with water to form dilute hydrochloric acid, which will corrode the primary distillation column and / or the top of the atmospheric distillation column and the top condensation system. In hydrotreating units, ammonium chloride will form, causing salt deposits and blockages in heat exchangers and other areas, which will seriously affect the long-term stable operation of the refining unit.

[0004] Commonly used methods for removing organochlorines include catalytic methods, adsorption methods, chemical methods, and phase transfer nucleophilic substitution methods. Phase transfer nucleophilic substitution methods are characterized by low cost, convenient phase transfer agent addition, no introduction of impurities, and good dechlorination effect, making them one of the commonly used methods in crude oil dechlorination. In the research of phase transfer nucleophilic substitution methods, developing efficient phase transfer agents is key to improving dechlorination efficiency. Liu Gongzhao et al. developed a crude oil organochlorine removal agent using benzyltriethylammonium hydroxide as the phase transfer agent, which reduced the chlorine content in the cooling water at the top of the atmospheric and vacuum distillation units by 69.7% and 18.9%, respectively. Jiang Tiehui et al. reported a crude oil dechlorination agent containing tetrabutylammonium bromide, achieving a 45.8% removal rate of organochlorines in simulated crude oil. Pan Xiaoyan et al. employed a phase-transfer nucleophilic substitution method. First, a phase-transfer agent transfers organochlorine molecules from the oil phase to the aqueous phase. Then, a substitution reaction occurs with a nucleophile, generating water-soluble inorganic chloride ions that are removed. The reaction time is 80 minutes, and the organochlorine removal rate reaches 82.2%. However, the removal effect and efficiency of organochlorine from crude oil in existing technologies still need further improvement. Summary of the Invention

[0005] To address the aforementioned problems in the prior art, the present invention provides a method for removing organochlorine from crude oil using a microreactor, comprising: introducing crude oil and dechlorination components into the microreactor for mixing, causing a dechlorination reaction, and then separating the crude oil and dechlorination components; wherein the dechlorination components include a phase transfer agent, a nucleophile, and a solvent.

[0006] This invention provides a new process and method for efficiently removing organochlorine from crude oil using a microreactor. By utilizing the advantages of the high controllability and high heat transfer efficiency of the microreactor, the crude oil can be uniformly and fully contacted with the dechlorination components to undergo a removal reaction, enabling safe, efficient and continuous production. This solves the problems of long reaction time and poor removal effect in the removal of organochlorine from crude oil in the prior art.

[0007] According to some embodiments of the present invention, the reaction temperature of the dechlorination reaction is 110-140°C.

[0008] According to some embodiments of the present invention, the reaction temperature of the dechlorination reaction is 120-130°C.

[0009] In this invention, the reaction temperature of the dechlorination reaction is limited to 120-130℃, which can further improve the removal rate of organic chlorine from crude oil.

[0010] In this invention, the reaction temperature of the dechlorination reaction is controlled by preheating the crude oil and dechlorination components to 110-140°C and setting the reaction channel of the micro-reaction setup in an oil bath at 110-140°C.

[0011] According to some embodiments of the present invention, the preheating of crude oil is carried out in a preheating reaction coil.

[0012] According to some embodiments of the present invention, the equivalent diameter of the preheating reaction coil is 0.4 mm and the length is 500 mm.

[0013] According to some embodiments of the present invention, the equivalent diameter of the reaction channel of the microreactor is 0.1-1 mm, preferably 0.2-0.6 mm, more preferably 0.2-0.4 m, and the length of the reaction channel is 100-600 mm, preferably 100-500 mm, more preferably 200-400 m.

[0014] According to some embodiments of the present invention, the residence time of the crude oil and dechlorinated components in the reaction channel is 0.2 to 20 min, preferably 0.2 to 10 min, and more preferably 1 to 8 min.

[0015] According to some embodiments of the present invention, the mass concentration of the phase transfer agent in the dechlorination component is 0.01-0.1%, preferably 0.02-0.07%; and the mass concentration of the nucleophile in the dechlorination component is 1-5%, preferably 2-4%.

[0016] According to some embodiments of the present invention, the phase transfer agent includes at least one of benzyltriethylammonium chloride, benzyltriethylammonium hydroxide, tetrabutylammonium hydroxide, and tetrabutylammonium bromide.

[0017] According to some embodiments of the present invention, the phase transfer agent is benzyltriethylammonium chloride.

[0018] In this invention, benzyltriethylammonium chloride is used as a phase transfer agent, which can further improve the removal rate of organic chlorine from crude oil compared to other phase transfer agents.

[0019] According to some embodiments of the present invention, the nucleophile includes at least one of sodium ethoxide, ethylenediamine, triethylamine, and dimethylformamide.

[0020] According to some embodiments of the present invention, the nucleophile is sodium ethoxide.

[0021] In this invention, sodium ethoxide is used as a nucleophile, which can further improve the removal rate of organochlorines in crude oil compared to using other nucleophiles.

[0022] According to some embodiments of the present invention, the solvent includes at least one of ethanol, propanol, acetaldehyde, and acetone, preferably ethanol.

[0023] According to some embodiments of the present invention, the volumetric flow ratio of crude oil to dechlorinated components is 10-50:1, preferably 20-40:1.

[0024] According to some embodiments of the present invention, the separation is performed using a centrifuge; preferably, the centrifuge rotates at a speed of 2500-3500 r / min.

[0025] According to some embodiments of the present invention, the separated solvent is recycled. Solvent recycling reduces costs and is environmentally friendly.

[0026] The beneficial effects of this invention are at least as follows:

[0027] Compared with existing batch dechlorination reaction technology, the microreactor method for removing organic chlorine from crude oil provided by this invention can effectively reduce the mass transfer resistance of the dechlorination reaction, improve the reaction efficiency, and significantly improve the removal rate of organic chlorine. It can also be operated continuously. The entire process is closed-loop, with high safety, and the equipment is relatively small, showing broad prospects for practical industrial applications. Attached Figure Description

[0028] Figure 1 This is a schematic flowchart of the method for removing organochlorine from crude oil using a microreactor provided by the present invention.

[0029] Among them, 1-organic solvent tank, 2-crude oil storage tank, 3-oil bath, 4-crude oil injection pump, 5-crude oil preheating reaction coil, 6-T-shaped injection point, 7-reaction coil, 8-organic solvent pump, 9-separation equipment, 10-removed crude oil storage tank. Detailed Implementation

[0030] To make the technical problem to be solved, the technical solution, and the beneficial effects of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely for illustrating this patent and do not limit the scope of protection of this invention in any way.

[0031] Unless otherwise defined, the technical terms used in the following embodiments have the same meaning as commonly understood by those skilled in the art. Unless otherwise specified, the reagents used in the following embodiments are conventional biochemical reagents; the raw materials, instruments, and equipment used in the following embodiments can all be obtained commercially or by existing methods; unless otherwise specified, the reagent dosages are those used in routine experimental operations; unless otherwise specified, the experimental methods are conventional methods.

[0032] In the various embodiments and comparative examples of the present invention, the total chlorine content in crude oil was determined by coulometric method; the salt content in crude oil was determined by coulometric method; and the inorganic chlorine content was converted using sodium chloride as a standard substance.

[0033] Removal rate calculation method: Removal rate = [1 - (total chlorine content after removal - salt content after removal × mass fraction of chlorine in sodium chloride) / (total chlorine content before removal - salt content before removal × mass fraction of chlorine in sodium chloride)] × 100%.

[0034] In the various embodiments and comparative examples of the present invention, the total chlorine of the crude oil before dechlorination treatment was 75.85 mg / kg, the salt content was 36.15 mg NaCl / L, and the calculated organic chlorine content was 54.22 mg / kg.

[0035] The specific process of the microreactor method for removing organochlorine from crude oil provided by this invention is as follows: Figure 1As shown, crude oil is first preheated in the crude oil preheating reaction coil via crude oil injection pump 4, and then introduced into the microreactor. The dechlorination component is introduced into the microreactor via organic solvent pump 8. After the crude oil and dechlorination component are mixed, a crude oil-dechlorination component two-phase system is formed. The dechlorination component is dispersed into small droplets by the crude oil. During the process of passing through the reaction coil 7, a dechlorination reaction occurs to remove organic chlorine from the crude oil. Then, it enters the centrifuge 9 for separation. The separated crude oil is sent to the dechlorinated crude oil storage tank 10 for storage.

[0036] Example 1

[0037] A method for removing organochlorine from crude oil using a microreactor includes: mixing crude oil and dechlorination components by passing them into the microreactor and mixing them, causing a dechlorination reaction at 125°C, and then separating the crude oil and dechlorination components using a centrifuge at a speed of 3000 r / min.

[0038] The microreactor has a channel diameter of 0.4 mm and a length of 300 mm, and the residence time of crude oil and dechlorinated components in the reaction coil is 7.25 min.

[0039] The dechlorination component consists of benzyltriethylammonium chloride, sodium ethoxide, and ethanol, wherein the mass concentration of benzyltriethylammonium chloride in the dechlorination component is 0.05% and the mass concentration of sodium ethoxide in the dechlorination component is 3%.

[0040] The flow rate of crude oil is 5 μL / min, the flow rate of the dechlorination component is 0.2 μL / min, and the calculated mass concentration of benzyltriethylammonium chloride in the crude oil-dechlorination component two-phase system is 0.0019%, and the mass concentration of sodium ethoxide is 0.1154%.

[0041] The dechlorination effect of the separated crude oil was tested. The test results were as follows: the total chlorine content of the separated crude oil was 4.982 mg / kg, the salt content was 1.004 mg NaCl / L, the calculated organic chlorine content was 4.380 mg / kg, and the removal rate was 91.92%.

[0042] Example 2

[0043] A method for removing organochlorine from crude oil using a microreactor includes: passing crude oil and dechlorination components into the microreactor for mixing, conducting a dechlorination reaction at 120°C, and then separating the crude oil and dechlorination components using a centrifuge at a speed of 3000 r / min.

[0044] The microreactor has a channel diameter of 0.2 mm and a length of 200 mm, and the residence time of crude oil and dechlorinated components in the reaction coil is 1.53 min.

[0045] The dechlorination component consists of benzyltriethylammonium chloride, sodium ethoxide, and ethanol, wherein the mass concentration of benzyltriethylammonium chloride in the dechlorination component is 0.07% and the mass concentration of sodium ethoxide in the dechlorination component is 4%.

[0046] The flow rate of crude oil is 4 μL / min, the flow rate of the dechlorination component is 0.1 μL / min, and the calculated mass concentration of benzyltriethylammonium chloride in the crude oil-dechlorination component two-phase system is 0.0017%, and the mass concentration of sodium ethoxide is 0.0976%.

[0047] The dechlorination effect of the separated crude oil was tested. The test results were as follows: the total chlorine content of the separated crude oil was 5.281 mg / kg, the salt content was 1.329 mg NaCl / L, the calculated organic chlorine content was 4.484 mg / kg, and the removal rate was 91.73%.

[0048] Example 3

[0049] A method for removing organochlorine from crude oil using a microreactor includes: mixing crude oil and dechlorination components by passing them into the microreactor and performing a dechlorination reaction at 130°C; then separating the crude oil and dechlorination components using a centrifuge at a speed of 3000 r / min.

[0050] The microreactor has a channel diameter of 0.3 mm and a length of 400 mm, and the residence time of crude oil and dechlorinated components in the reaction coil is 4.49 min.

[0051] The dechlorination component consists of benzyltriethylammonium chloride, sodium ethoxide, and ethanol, wherein the mass concentration of benzyltriethylammonium chloride in the dechlorination component is 0.02% and the mass concentration of sodium ethoxide in the dechlorination component is 2%.

[0052] The flow rate of crude oil was 6 μL / min, the flow rate of the dechlorination component was 0.3 μL / min, and the calculated mass concentration of benzyltriethylammonium chloride in the crude oil-dechlorination component two-phase system was 0.0010%, and the mass concentration of sodium ethoxide was 0.0952%.

[0053] The dechlorination effect of the separated crude oil was tested. The test results were as follows: the total chlorine content of the separated crude oil was 5.875 mg / kg, the salt content was 1.615 mg NaCl / L, the calculated organic chlorine content was 4.906 mg / kg, and the removal rate was 90.95%.

[0054] Example 4

[0055] A method for removing organochlorine from crude oil using a microreactor differs from Example 1 only in that the dechlorination reaction temperature is 110°C.

[0056] The dechlorination effect of the separated crude oil was tested. The test results were as follows: the total chlorine content of the separated crude oil was 7.668 mg / kg, the salt content was 0.987 mg NaCl / L, the calculated organic chlorine content was 7.076 mg / kg, and the removal rate was 86.95%.

[0057] Example 5

[0058] A method for removing organochlorine from crude oil using a microreactor differs from Example 1 only in that the dechlorination reaction temperature is 150°C.

[0059] The dechlorination effect of the separated crude oil was tested. The test results were as follows: the total chlorine content of the separated crude oil was 7.442 mg / kg, the salt content was 1.098 mg NaCl / L, the calculated organic chlorine content was 6.783 mg / kg, and the removal rate was 87.49%.

[0060] Example 6

[0061] A method for removing organochlorine compounds from crude oil using a microreactor differs from Example 1 only in that benzyltriethylammonium chloride is replaced with benzyltriethylammonium hydroxide.

[0062] The dechlorination effect of the separated crude oil was tested. The test results were as follows: the total chlorine content of the separated crude oil was 8.648 mg / kg, the salt content was 1.064 mg NaCl / L, the calculated organic chlorine content was 8.010 mg / kg, and the removal rate was 85.23%.

[0063] Example 7

[0064] A method for removing organochlorine compounds from crude oil using a microreactor differs from Example 1 only in that benzyltriethylammonium chloride is replaced with tetrabutylammonium hydroxide.

[0065] The dechlorination effect of the separated crude oil was tested. The test results were as follows: the total chlorine content of the separated crude oil was 8.977 mg / kg, the salt content was 2.174 mg NaCl / L, the calculated organic chlorine content was 7.673 mg / kg, and the removal rate was 85.85%.

[0066] Example 8

[0067] A method for removing organochlorine compounds from crude oil using a microreactor differs from Example 1 only in that benzyltriethylammonium chloride is replaced with tetrabutylammonium bromide.

[0068] The dechlorination effect of the separated crude oil was tested. The test results were as follows: the total chlorine content of the separated crude oil was 9.342 mg / kg, the salt content was 2.152 mg NaCl / L, the calculated organic chlorine content was 8.051 mg / kg, and the removal rate was 85.15%.

[0069] Example 9

[0070] A method for removing organochlorine compounds from crude oil using a microreactor differs from Example 1 only in that sodium ethoxide is replaced with ethylenediamine.

[0071] The dechlorination effect of the separated crude oil was tested. The test results were as follows: the total chlorine content of the separated crude oil was 8.476 mg / kg, the salt content was 1.622 mg NaCl / L, the calculated organic chlorine content was 7.503 mg / kg, and the removal rate was 86.16%.

[0072] Example 10

[0073] A method for removing organochlorine compounds from crude oil using a microreactor differs from Example 1 only in that sodium ethoxide is replaced with triethylamine.

[0074] The dechlorination effect of the separated crude oil was tested. The test results were as follows: the total chlorine content of the separated crude oil was 9.165 mg / kg, the salt content was 2.497 mg NaCl / L, the calculated organic chlorine content was 7.667 mg / kg, and the removal rate was 85.86%.

[0075] Example 11

[0076] A method for removing organochlorine compounds from crude oil using a microreactor differs from Example 1 only in that sodium ethoxide is replaced with dimethylformamide.

[0077] The dechlorination effect of the separated crude oil was tested. The test results were as follows: the total chlorine content of the separated crude oil was 9.629 mg / kg, the salt content was 2.592 mg NaCl / L, the calculated organic chlorine content was 8.074 mg / kg, and the removal rate was 85.11%.

[0078] Example 12

[0079] A method for removing organochlorine from crude oil using a microreactor differs from Example 1 only in that ethanol is replaced with propanol.

[0080] The dechlorination effect of the separated crude oil was tested. The test results were as follows: the total chlorine content of the separated crude oil was 7.932 mg / kg, the salt content was 1.802 mg NaCl / L, the calculated organic chlorine content was 6.851 mg / kg, and the removal rate was 87.36%.

[0081] Example 13

[0082] A method for removing organochlorine compounds from crude oil using a microreactor differs from Example 1 only in that ethanol is replaced with acetaldehyde.

[0083] The dechlorination effect of the separated crude oil was tested. The test results were as follows: the total chlorine content of the separated crude oil was 9.113 mg / kg, the salt content was 2.012 mg NaCl / L, the calculated organic chlorine content was 7.906 mg / kg, and the removal rate was 85.42%.

[0084] Example 14

[0085] A method for removing organochlorine compounds from crude oil using a microreactor differs from Example 1 only in that ethanol is replaced with acetone.

[0086] The dechlorination effect of the separated crude oil was tested. The test results were as follows: the total chlorine content of the separated crude oil was 8.247 mg / kg, the salt content was 1.933 mg NaCl / L, the calculated organic chlorine content was 7.087 mg / kg, and the removal rate was 86.93%.

[0087] Comparative Example 1

[0088] The crude oil is dechlorinated using an electrostatic desalting method. The specific method includes: after preheating the crude oil, it is fully emulsified with water, demulsifier and chlorine transfer agent. Under the action of strong and weak electric fields, water droplets are accumulating and settling. Inorganic salts and removed organic chlorine are discharged from the bottom of the desalting tank in the water, and the dechlorinated crude oil is discharged from the top of the tank.

[0089] Specific parameters and conditions: water volume is 5wt%, demulsifier (PR-5 type oil-soluble demulsifier) ​​mass concentration is 0.0015%, chlorine transfer agent (LZ-3 type oil-soluble chlorine transfer agent) mass concentration is 0.002%, reaction temperature is 125℃, and reaction time is 20min.

[0090] The dechlorination effect of the crude oil after desalting was tested. The test results were as follows: the total chlorine of the crude oil after desalting was 11.976 mg / kg, the salt content was 1.982 mg NaCl / L, the calculated organic chlorine content was 10.787 mg / kg, and the removal rate was 80.11%.

[0091] The comparison between Comparative Example 1 and Example 1 is as follows:

[0092]

[0093] The comparison results above show that the micro-reaction device provided by the present invention has a higher organic chlorine removal rate and takes less time compared with the crude oil electrostatic desalting method, and the organic chlorine removal efficiency is higher.

[0094] Furthermore, the micro-reaction device method for removing organic chlorine from crude oil provided by this invention has significant advantages over the method of removing organic chlorine using a batch reactor, as it does not require reaction under an electric field. The process is simpler, consumes less energy, and has a higher removal efficiency of organic chlorine.

[0095] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. A method for removing organochlorine compounds from crude oil using a microreactor, characterized in that, include: Crude oil and dechlorinated components are mixed in a microreactor to undergo a dechlorination reaction, and then the crude oil and dechlorinated components are separated; the dechlorinated components include a phase transfer agent, a nucleophile, and a solvent; The phase transfer agent is benzyltriethylammonium chloride; The nucleophile is sodium ethoxide; The solvent is ethanol.

2. The method according to claim 1, characterized in that, The dechlorination reaction is carried out at a temperature of 110-140℃.

3. The method according to claim 2, characterized in that, The dechlorination reaction is carried out at a temperature of 120-130℃.

4. The method according to any one of claims 1-3, characterized in that, The equivalent diameter of the reaction channel of the microreactor is 0.1-1 mm, and the length of the reaction channel is 100-600 mm. And / or, the residence time of the crude oil and dechlorinated components in the reaction channel is 0.2 to 20 minutes.

5. The method according to claim 4, characterized in that, The equivalent diameter of the reaction channel of the microreactor is 0.2-0.6 mm, and the length of the reaction channel is 100-500 mm. And / or, the residence time of the crude oil and dechlorinated components in the reaction channel is 0.2 to 10 minutes.

6. The method according to any one of claims 1-3, characterized in that, The phase transfer agent has a mass concentration of 0.01-0.1% in the dechlorination component; the nucleophile has a mass concentration of 1-5% in the dechlorination component.

7. The method according to any one of claims 1-3, characterized in that, The volumetric flow rate ratio of crude oil to dechlorinated components is 10-50:

1.

8. The method according to claim 7, characterized in that, The volumetric flow rate ratio of crude oil to dechlorinated components is 20-40:

1.

9. The method according to any one of claims 1-3, characterized in that, The separation was performed using a centrifuge.

10. The method according to claim 9, characterized in that, The centrifuge speed is 2500-3500 r / min.

11. The method according to any one of claims 1-3, characterized in that, The separated solvent is recycled.

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