Method for removing organochlorine in crude oil by using micro-reaction equipment

Abstract

The invention relates to the technical field of crude oil dechlorination, and provides a method for removing organochlorine in crude oil by using micro-reaction equipment. The method comprises the following steps: crude oil and a dechlorination component are introduced into micro-reaction equipment to be mixed, and the crude oil and the dechlorination component are separated after a dechlorination reaction; the dechlorination component comprises a phase transfer agent, a nucleophilic reagent and a solvent. Compared with an existing kettle type dechlorination reaction technology, the method for removing the organochlorine in the crude oil through the micro-reaction equipment has the advantages that the mass transfer resistance of the dechlorination reaction can be effectively reduced, the reaction efficiency is improved, the removal rate of the organochlorine is obviously improved, and continuous operation can be achieved; the whole treatment process runs in a closed mode, safety is high, equipment is small, and the method has wide actual industrial application prospects.

Description

Technical Field

[0001] The invention relates to the technical field of crude oil dechlorination, and more specifically to a method for removing organic chlorine from crude oil by using a micro-reaction device. Background Art

[0002] In recent years, there have been many production and product quality accidents caused by excessive organic chloride content in crude oil / distillate oil in China. In particular, in May 2013, Shengli crude oil contained abnormally high chlorine content, which had a huge impact on the normal production of many oil refineries in North China and along the Yangtze River. In addition, organic chloride in oil products will also pose a potential threat to environmental quality after combustion. Therefore, it is of great significance to reduce the content of organic chloride in oil products.

[0003] There are two main sources of organic chlorides in crude oil: one is the natural organic chlorides in crude oil; the other is the chlorine-containing chemical additives added artificially during crude oil extraction, transportation and processing. Organic chlorides in crude oil generally include monochloropropane, dichloroethane, trichloromethane, dichloromethane, carbon tetrachloride and epichlorohydrin, etc. The types of organic chlorides contained in crude oil from different oil fields will also be different. The organic chlorides in crude oil distillates are mainly concentrated in the naphtha fraction. Organic chlorides are hydrolyzed in the distillation unit, and the generated HCl will form dilute hydrochloric acid when it comes into contact with water, which will cause corrosion to the primary distillation tower and (or) the top of the atmospheric tower and the top condensation system; in the hydrogenation unit, ammonium chloride will form salt blockage in the heat exchanger, etc., which will seriously affect the long-term stable operation of the refinery unit.

[0004] Commonly used methods for removing organic chlorine include catalytic method, adsorption method, chemical method, phase transfer nucleophilic substitution method, etc. Phase transfer nucleophilic substitution method has the characteristics of low cost, convenient filling of phase transfer agent, no introduction of impurities and good dechlorination effect. It is one of the commonly used methods in crude oil industrial dechlorination. In the research of phase transfer nucleophilic substitution method, the development of efficient phase transfer agent is the key to improving the dechlorination effect. Liu Gongzhao et al. developed a crude oil organic chlorine removal agent with benzyltriethylammonium hydroxide as phase transfer agent, which reduced the chlorine content in the atmospheric tower top and vacuum tower top cooling water of the atmospheric and vacuum distillation unit by 69.7% and 18.9%, respectively. Jiang Tiehui et al. reported a crude oil dechlorination agent containing tetrabutylammonium bromide, which achieved a 45.8% removal rate of organic chlorine in simulated crude oil. Pan Xiaoyan and others used the phase transfer nucleophilic substitution method, firstly, the phase transfer agent transferred the organic chlorine molecules from the oil phase to the water phase, and then the substitution reaction occurred with the nucleophilic reagent to generate water-soluble inorganic chloride ions to be removed. The reaction time was 80 minutes, and the organic chlorine removal rate could reach 82.2%. However, the removal effect and efficiency of organic chlorine in crude oil in the existing technology need to be further improved. Summary of the invention

[0005] In order to solve the above problems in the prior art, the present invention provides a method for removing organic chlorine from crude oil by using a micro-reactor, comprising: introducing crude oil and a dechlorination component into the micro-reactor to mix, and then separating the crude oil and the dechlorination component after a dechlorination reaction occurs; the dechlorination component comprises a phase transfer agent, a nucleophilic reagent and a solvent.

[0006] The present invention provides a new process and method for efficiently removing organic chlorine from crude oil by using a micro-reactor. By utilizing the advantages of the micro-reactor, which is highly controllable and has high heat transfer efficiency, the crude oil can be evenly and fully contacted with the dechlorination component to undergo a removal reaction, thereby achieving safe, efficient and continuous production, and solving the problems of long reaction time and poor removal effect in the prior art for removing organic chlorine from crude oil.

[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 the present invention, the reaction temperature of the dechlorination reaction is limited to 120-130° C., which can further improve the removal rate of organic chlorine in crude oil.

[0010] In the present invention, the reaction temperature control of the dechlorination reaction is achieved by preheating the crude oil and the dechlorination component to 110-140°C and placing the reaction channel of the micro-reaction device in an oil bath at 110-140°C.

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

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

[0013] According to some embodiments of the present invention, the equivalent diameter of the reaction channel of the micro-reaction device 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 the dechlorinated component 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%; the mass concentration of the nucleophilic agent 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 invention, the phase transfer agent is benzyltriethylammonium chloride.

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

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

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

[0021] In the present invention, sodium ethoxide is used as a nucleophilic agent, which can further improve the removal rate of organic chlorine in crude oil compared with other nucleophilic agents.

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

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

[0024] According to some embodiments of the present invention, a centrifugal device is used for the separation; preferably, the rotation speed of the centrifugal device is 2500-3500 r / min.

[0025] According to some embodiments of the present invention, the separated solvent is recycled. Recycling the solvent can reduce costs and is environmentally friendly.

[0026] The beneficial effects of the present invention are at least:

[0027] Compared with the existing kettle-type dechlorination reaction technology, the method for removing organic chlorine from crude oil by using a micro-reactor provided by the present 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, and can be operated continuously; the entire treatment process is closed and operated, with high safety, and the equipment is small, and has broad practical industrial application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The present invention provides a schematic flow diagram of a method for removing organic chlorine from crude oil using a micro-reactor.

[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 structure injection point, 7-reaction coil, 8-organic solvent pump, 9-separation equipment, 10-post-desorption crude oil storage tank. DETAILED DESCRIPTION

[0030] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain this patent in detail and do not limit the scope of protection of the present invention in any way.

[0031] Unless otherwise defined, the technical terms used in the following examples have the same meanings as those generally understood by those skilled in the art to which the present invention belongs. The reagents used in the following examples, unless otherwise specified, are all conventional biochemical reagents; the raw materials, instruments and equipment used in the following examples, etc., can all be purchased on the market or can be obtained by existing methods; the reagent amounts, unless otherwise specified, are the reagent amounts used in conventional experimental operations; the experimental methods, unless otherwise specified, are all conventional methods.

[0032] In each embodiment and comparative example of the present invention, the total chlorine content in crude oil is determined by the coulometric method; the salt content in crude oil is measured by the coulometric method; and the inorganic chlorine content is converted using sodium chloride as a standard substance.

[0033] Calculation method of removal rate: 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 each of the embodiments and comparative examples of the present invention, the total chlorine content of the crude oil before dechlorination treatment is 75.85 mg / kg, the salt content is 36.15 mg NaCl / L, and the calculated organic chlorine content is 54.22 mg / kg.

[0035] The specific process of the method for removing organic chlorine from crude oil using a micro-reactor provided by the present invention is as follows: Figure 1As shown. The crude oil is first introduced into the crude oil preheating reaction coil for preheating through the crude oil injection pump 4, and then introduced into the micro-reactor, and the dechlorination component is introduced into the micro-reactor through the organic solvent pump 8; the crude oil and the dechlorination component are mixed to form a crude oil-dechlorination component two-phase system, and the dechlorination component is dispersed into small droplets by the crude oil, and a dechlorination reaction occurs in the process of passing through the reaction coil 7 to remove organic chlorine in the crude oil, and then enters the centrifugal device 9 for separation, and the separated crude oil is sent to the dechlorinated crude oil storage tank 10 for storage.

[0036] Example 1

[0037] A method for removing organic chlorine from crude oil by using a micro-reactor, comprising: introducing crude oil and a dechlorination component into a micro-reactor to mix, causing a dechlorination reaction at 125° C., and then separating the crude oil and the dechlorination component by using a centrifugal device, wherein the rotation speed of the centrifugal device is 3000 r / min;

[0038] The channel diameter of the reaction coil in the micro-reactor is 0.4 mm, the length is 300 mm, and the residence time of the crude oil and the dechlorinated components in the reaction coil is 7.25 min;

[0039] The dechlorination component is composed of benzyltriethylammonium chloride, sodium ethoxide and ethanol, wherein the mass concentration of benzyltriethylammonium chloride in the dechlorination component is 0.05%; 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 dechlorination component is 0.2 μL / min, the mass concentration of benzyltriethylammonium chloride in the crude oil-dechlorination component two-phase system is calculated to be 0.0019%, and the mass concentration of sodium ethoxide is 0.1154%;

[0041] The dechlorination effect of the separated crude oil was tested, and 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 mgNaCl / 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 organic chlorine from crude oil by using a micro-reactor, comprising: introducing crude oil and a dechlorination component into a micro-reactor to mix, causing a dechlorination reaction at 120° C., and then separating the crude oil and the dechlorination component by using a centrifugal device, wherein the rotation speed of the centrifugal device is 3000 r / min;

[0044] The channel diameter of the reaction coil in the micro-reactor is 0.2 mm, the length is 200 mm, and the residence time of the crude oil and the dechlorinated components in the reaction coil is 1.53 min;

[0045] The dechlorination component is composed of benzyltriethylammonium chloride, sodium ethoxide and ethanol, wherein the mass concentration of benzyltriethylammonium chloride in the dechlorination component is 0.07%; 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 dechlorination component is 0.1 μL / min, the mass concentration of benzyltriethylammonium chloride in the crude oil-dechlorination component two-phase system is calculated to be 0.0017%, and the mass concentration of sodium ethoxide is 0.0976%;

[0047] The dechlorination effect of the separated crude oil was tested, and 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 mgNaCl / 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 organic chlorine from crude oil by using a micro-reactor, comprising: introducing crude oil and a dechlorination component into a micro-reactor to mix, causing a dechlorination reaction at 130° C., and then separating the crude oil and the dechlorination component by using a centrifugal device, wherein the rotation speed of the centrifugal device is 3000 r / min;

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

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

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

[0053] The dechlorination effect of the separated crude oil was tested, and 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 mgNaCl / 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 organic chlorine from crude oil using a micro-reactor is different from Example 1 only in that the temperature of the dechlorination reaction is 110°C.

[0056] The dechlorination effect of the separated crude oil was tested, and 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 mgNaCl / 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 organic chlorine from crude oil using a micro-reactor is different from Example 1 only in that the temperature of the dechlorination reaction is 150°C.

[0059] The dechlorination effect of the separated crude oil was tested, and 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 mgNaCl / 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 organic chlorine from crude oil using a micro-reactor is different from Example 1 only in that benzyltriethylammonium chloride is replaced by benzyltriethylammonium hydroxide.

[0062] The dechlorination effect of the separated crude oil was tested, and 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 mgNaCl / 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 organic chlorine from crude oil using a micro-reactor is different from Example 1 only in that benzyltriethylammonium chloride is replaced by tetrabutylammonium hydroxide.

[0065] The dechlorination effect of the separated crude oil was tested, and 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 mgNaCl / 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 organic chlorine from crude oil using a micro-reactor is different from Example 1 in that benzyltriethylammonium chloride is replaced by tetrabutylammonium bromide.

[0068] The dechlorination effect of the separated crude oil was tested, and 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 mgNaCl / 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 organic chlorine from crude oil using a micro-reactor is different from Example 1 only in that sodium ethoxide is replaced by ethylenediamine.

[0071] The dechlorination effect of the separated crude oil was tested, and 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 mgNaCl / 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 organic chlorine from crude oil using a micro-reactor is different from Example 1 only in that sodium ethoxide is replaced by triethylamine.

[0074] The dechlorination effect of the separated crude oil was tested, and 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 mgNaCl / L, the calculated organic chlorine content was 7.667 mg / kg, and the removal rate was 85.86%.

[0075] Embodiment 11

[0076] A method for removing organic chlorine from crude oil using a micro-reactor is different from Example 1 only in that sodium ethoxide is replaced by dimethylformamide.

[0077] The dechlorination effect of the separated crude oil was tested, and 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 mgNaCl / 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 organic chlorine from crude oil using a micro-reactor is different from Example 1 only in that ethanol is replaced by propanol.

[0080] The dechlorination effect of the separated crude oil was tested, and 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 mgNaCl / L, the calculated organic chlorine content was 6.851 mg / kg, and the removal rate was 87.36%.

[0081] Embodiment 13

[0082] A method for removing organic chlorine from crude oil using a micro-reactor is different from Example 1 only in that ethanol is replaced by acetaldehyde.

[0083] The dechlorination effect of the separated crude oil was tested, and 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 mgNaCl / L, the calculated organic chlorine content was 7.906 mg / kg, and the removal rate was 85.42%.

[0084] Embodiment 14

[0085] A method for removing organic chlorine from crude oil using a micro-reactor is different from Example 1 only in that ethanol is replaced by acetone.

[0086] The dechlorination effect of the separated crude oil was tested, and 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 mgNaCl / 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 by the crude oil electrical desalting method. The specific method includes: preheating the crude oil and fully emulsifying it with water, demulsifier and chlorine transfer agent, and then under the action of strong and weak electric fields, water droplets are accumulated and settled, and 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 parameter conditions: water injection volume is 5wt%, demulsifier (PR-5 oil-soluble demulsifier) ​​mass concentration is 0.0015%, chlorine transfer agent (LZ-3 oil-soluble chlorine transfer agent) mass concentration is 0.002%, reaction temperature is 125°C, and reaction time is 20min.

[0090] The dechlorination effect of the desalted crude oil was tested, and the test results showed that the total chlorine content of the desalted crude oil was 11.976 mg / kg, the salt content was 1.982 mgNaCl / 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] From the above comparison results, it can be concluded that the method for removing organic chlorine from crude oil by using a micro-reactor provided by the present invention has a higher organic chlorine removal rate than the crude oil electrical desalting method, takes less time, and has a higher organic chlorine removal efficiency.

[0094] Moreover, compared with the method of removing organic chlorine from crude oil using a kettle reactor, the method of removing organic chlorine from crude oil using a micro-reactor provided by the present invention does not require reaction under electric field conditions, is simpler in process, has lower energy consumption, and has higher organic chlorine removal efficiency, thus having obvious advantages.

[0095] It should be noted that the embodiments described above are only used to explain the present invention and do not constitute any limitation to 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 words, rather than restrictive words. The present invention may be modified as specified within the scope of the claims of the present invention, and the present invention may be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein, on the contrary, the present invention can be extended to all other methods and applications with the same functions.

Claims

1. A method for removing organic chlorine from crude oil using a micro-reactor, characterized in that: include: The crude oil and the dechlorinated component are introduced into the micro-reactor and mixed, and the crude oil and the dechlorinated component are separated after the dechlorination reaction occurs; The dechlorination components include a phase transfer agent, a nucleophile and a solvent.

2. The method according to claim 1, characterized in that The reaction temperature of the dechlorination reaction is 110-140°C, preferably 120-130°C.

3. The method according to claim 1 or 2, characterized in that: The equivalent diameter of the reaction channel of the micro-reaction device is 0.1-1 mm, preferably 0.2-0.6 mm, and the length of the reaction channel is 100-600 mm, preferably 100-500 mm; And / or, the residence time of the crude oil and the dechlorinated component in the reaction channel is 0.2 to 20 minutes, preferably 0.2 to 10 minutes.

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

5. The method according to any one of claims 1 to 4, characterized in that The phase transfer agent includes at least one of benzyltriethylammonium chloride, benzyltriethylammonium hydroxide, tetrabutylammonium hydroxide and tetrabutylammonium bromide, preferably benzyltriethylammonium chloride.

6. The method according to any one of claims 1 to 5, characterized in that The nucleophilic agent includes at least one of sodium ethoxide, ethylenediamine, triethylamine and dimethylformamide, preferably sodium ethoxide.

7. The method according to any one of claims 1 to 6, characterized in that The solvent includes at least one of ethanol, propanol, acetaldehyde and acetone, preferably ethanol.

8. The method according to any one of claims 1 to 7, characterized in that The volume flow ratio of the crude oil to the dechlorination component is 10-50:1, preferably 20-40:

1.

9. The method according to any one of claims 1 to 8, characterized in that The separation is performed using a centrifugal device; preferably, the rotation speed of the centrifugal device is 2500-3500r / min.

10. The method according to any one of claims 1 to 9, characterized in that The separated solvent is recycled.

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