Preparation method and system for desolventizing and refining C5 petroleum resin capable of retarding corrosion

Abstract

The invention relates to a preparation method and system for desolventizing and refining corrosion-retarding C5 petroleum resin, and belongs to the technical field of petrochemical industry. The method comprises the following steps: obtaining crude resin oil; desolventizing and refining the crude resin to obtain C5 petroleum resin; wherein the step of desolventizing and refining comprises normal-pressure steam stripping and reduced-pressure steam stripping, a corrosion inhibitor is injected in the normal-pressure steam stripping and the reduced-pressure steam stripping so as to reduce pipeline corrosion, and the corrosion inhibitor is a liquid-phase corrosion inhibitor; liquid phase corrosion inhibitor injection is adopted instead of gas phase injection such as ammonia gas injection. The liquid-phase corrosion inhibitor can enter the condenser along with the flowing direction of a medium and the gravity to generate neutralization reaction, and compared with gas-phase ammonia gas, the liquid-phase corrosion inhibitor is more stable, and the anti-corrosion effect can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of petrochemical engineering, and particularly relates to a preparation method and system for desolventizing and refining C5 petroleum resin for corrosion mitigation. Background Art

[0002] In a C5 petroleum resin device, two main types of catalysts are mainly used for initiating polymerization to produce high-grade petroleum resins. For the injection method of solid-phase catalyst, very strict requirements are imposed on the content of each component in the reaction kettle. Trace amounts of water can act as a co-initiator to initiate polymerization, while excessive water acts as a terminator to terminate polymerization. For the injection method of liquid-phase catalyst, currently, organic chlorides such as dichloroethane are often used as co-initiators to initiate polymerization, and these organic chlorides enter the polymerization production system along with the catalyst. Regardless of the injection method, during the polymerization process of catalyst aluminum trichloride, side reactions such as hydrolysis, addition, and substitution will more or less occur to generate chlorides. Some of these substances are removed during the alkali washing stage, while some are mixed in the polymer or form organic chlorides that decompose at high temperatures, causing corrosion to the equipment pipelines of the subsequent desolventizing and refining system and affecting the long-term operation of the device.

[0003] The desolventizing and refining system usually includes atmospheric stripping and vacuum stripping. Atmospheric stripping uses the principle of boiling point difference to remove the recycled solvent for reuse, and vacuum stripping uses superheated steam to remove low-molecular polymers. At present, in domestic C5 petroleum resin devices, due to the influence of corrosion on the desolventizing and refining system, atmospheric stripping generally needs to be shut down for maintenance once a year; for vacuum stripping, especially the corrosion at the vacuum distillation top is more serious and needs to be overhauled once every six months.

[0004] At present, the main anti-corrosion measures adopted by the desolventizing and refining system are: injecting ammonia gas at the top of the atmospheric and vacuum columns. The ammonia injection process is manual flow regulation. When the system fluctuates, the injection amount is manually corrected to adapt to the fluctuations of production operations. There is a reaction lag and it is impossible to accurately adjust according to the pH value of the medium, resulting in equipment corrosion of the top condenser and its attached pipelines. Summary of the Invention

[0005] The present application provides a preparation method and system for desolventizing and refining C5 petroleum resin for corrosion mitigation to improve the anti-corrosion effect.

[0006] In the first aspect, the present application provides a preparation method for desolventizing and refining C5 petroleum resin for corrosion mitigation, and the method includes:

[0007] Obtaining crude resin oil;

[0008] Performing desolventizing and refining on the crude resin to obtain C5 petroleum resin;

[0009] Among them, the stripping and refining includes atmospheric stripping and vacuum stripping. An inhibitor is injected during the atmospheric stripping and vacuum stripping to reduce pipeline corrosion, and the inhibitor is a liquid-phase inhibitor.

[0010] As an alternative embodiment, the liquid-phase inhibitor includes organic ammonia.

[0011] As an alternative embodiment, the injection timing of the liquid-phase inhibitor is before the steam liquefaction phase change occurs in the atmospheric stripping and vacuum stripping.

[0012] As an alternative embodiment, the feed rate of the crude resin oil is 6.4 - 9.6 t / h, and the dosage of the inhibitor is 0.8 - 1.5 kg / h.

[0013] As an alternative embodiment, the feed rate of the crude resin oil is 9.6 - 14.4 t / h, and the dosage of the inhibitor is 1 - 2 kg / h.

[0014] As an alternative embodiment, the feed rate of the crude resin oil is 12.8 - 19.2 t / h, and the dosage of the inhibitor is 1.5 - 3 kg / h.

[0015] As an alternative embodiment, the material of the overhead cooler of the vacuum stripping is a corrosion-resistant material.

[0016] As an alternative embodiment, the corrosion-resistant material includes graphene.

[0017] In a second aspect, the present application provides a preparation system for the stripping and refining of C5 petroleum resin for corrosion mitigation, adopting the method described in the first aspect. The system includes:

[0018] An atmospheric stripping column for atmospheric stripping of the crude resin oil;

[0019] A vacuum stripping column for vacuum stripping of the bottom liquid of the atmospheric stripping. The vacuum stripping column is connected to the bottom of the atmospheric stripping column to receive the bottom liquid generated by the atmospheric stripping;

[0020] A feed pipeline for supplying the crude resin oil, and the feed pipeline is connected to the middle of the atmospheric gas column;

[0021] A first inhibitor supply pipeline, and the first inhibitor supply pipeline is connected between the column body and the overhead cooler of the atmospheric stripping column;

[0022] A second inhibitor supply pipeline, and the second inhibitor supply pipeline is connected between the column body and the overhead cooler of the vacuum stripping column.

[0023] As an alternative embodiment, the material of the overhead cooler of the vacuum stripping includes graphene.

[0024] The above technical solutions provided by the embodiments of the present application have the following advantages compared with the prior art:

[0025] For the method provided by the embodiments of the present application, liquid-phase corrosion inhibitor injection is adopted instead of gas-phase injection such as ammonia gas injection. The liquid-phase corrosion inhibitor will enter the condenser along with the medium flow direction and gravity to undergo a neutralization reaction, which is more stable than gas-phase ammonia gas and is beneficial to improving the anti-corrosion effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings herein are incorporated into the specification and constitute a part of this specification, showing embodiments consistent with the present application, and are used together with the specification to explain the principles of the present application.

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, other drawings can also be obtained based on these drawings without creative efforts.

[0028] Figure 1 It is a schematic flow chart of the method provided by the embodiments of the present application;

[0029] Figure 2 It is a schematic structural diagram of the system provided by the embodiments of the present application;

[0030] Reference numerals: 1 - atmospheric stripping column, 2 - vacuum stripping column, 3 - feed pipeline, 4 - first corrosion inhibitor supply pipeline, 5 - second corrosion inhibitor supply pipeline. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts belong to the scope of protection of the present application.

[0032] Unless otherwise specifically stated, various raw materials, reagents, instruments, and equipment used in the present application can be obtained through market purchases or can be prepared by existing methods.

[0033] C5 petroleum resin uses piperylene, monoolefins, etc. separated from ethylene cracking C5 as raw materials. Under certain conditions of the ratio of monoene to diene, through the action of the catalyst aluminum trichloride, a cationic polymerization reaction occurs to generate a polymerization liquid. The polymerization liquid enters the washing and sedimentation unit to remove residual catalyst to obtain crude resin oil. The crude resin oil is refined by removing solvents and small molecule polymers through the solvent stripping and refining unit, and finally C5 petroleum resin is obtained. The crude resin (polymer) from the washing and sedimentation unit contains chlorides, which corrodes the equipment pipelines of the subsequent solvent stripping and refining system, affecting the long-term operation of the device. At present, in domestic C5 petroleum resin plants, the solvent stripping and refining system is affected by corrosion. Generally, atmospheric stripping needs to be shut down for maintenance once a year; vacuum stripping, especially the corrosion at the top of the vacuum column is more serious, and it needs to be overhauled once every six months.

[0034] At present, the main anti-corrosion measures adopted in the solvent stripping and refining system are: injecting ammonia gas at the top of the atmospheric and vacuum columns. The ammonia injection process is manual flow regulation. When the system fluctuates, the injection volume is manually corrected to adapt to the fluctuations of production operations. There is a reaction lag and it is impossible to make precise adjustments according to the pH value of the medium, resulting in equipment corrosion of the top condenser and its attached pipelines.

[0035] The applicant intends to provide a preparation method and system for solvent stripping and refining of C5 petroleum resin to slow down corrosion, improve the anti-corrosion effect, inject a liquid phase corrosion inhibitor before the position where phase change occurs (top condenser) and adopt corresponding automatic control means. After adoption, the operation cycle of the device can reach more than 3 years.

[0036] Figure 1 The flow schematic diagram of the method provided by the embodiment of the present application is as Figure 1 As shown, the embodiment of the present application provides a preparation method for solvent stripping and refining of C5 petroleum resin to slow down corrosion, which is characterized in that the method includes:

[0037] S1. Obtain crude resin oil;

[0038] Specifically, in this embodiment, using piperylene, monoolefins, etc. separated from ethylene cracking C5 as raw materials, under certain conditions of the ratio of monoene to diene, through the action of the catalyst aluminum trichloride, a cationic polymerization reaction occurs to generate a polymerization liquid. The polymerization liquid enters the washing and sedimentation unit to remove residual catalyst to obtain crude resin oil.

[0039] S2. Carry out solvent stripping and refining on the crude resin to obtain C5 petroleum resin; wherein, the solvent stripping and refining includes atmospheric stripping and vacuum stripping, and a corrosion inhibitor is injected in the atmospheric stripping and vacuum stripping to reduce pipeline corrosion, and the corrosion inhibitor is a liquid phase corrosion inhibitor.

[0040] In some embodiments, the liquid-phase corrosion inhibitor includes organic ammonia. The injection timing of the liquid-phase corrosion inhibitor is before the steam liquefaction phase change of atmospheric stripping and vacuum stripping. In other words, the injection point of the corrosion inhibitor is at a position close to the condenser in front of the top condenser. According to theory and device operation experience, corrosion occurs at the position where phase change occurs, that is, inside the condenser. Injecting the corrosion inhibitor in front of the condenser can effectively achieve mixing and reduce the dosage of the corrosion inhibitor. The liquid-phase corrosion inhibitor is injected at the top of the atmospheric top condenser and the top of the vacuum top condenser, and real-time automatic control is carried out on the pH values of the aqueous phases at the bottoms of the atmospheric top reflux drum and the vacuum top reflux drum, with timely response.

[0041] In some embodiments, when the product scale is about 2.5 t / h, the feed rate of the crude resin oil is 6.4 - 9.6 t / h, and the dosage of the corrosion inhibitor is 0.8 - 1.5 kg / h. When the product scale is about 3.75 t / h, the feed rate of the crude resin oil is 9.6 - 14.4 t / h. When the product scale is about 5.0 t / h, the dosage of the corrosion inhibitor is 1 - 2 kg / h. When the feed rate of the crude resin oil is 12.8 - 19.2 t / h, the dosage of the corrosion inhibitor is 1.5 - 3 kg / h.

[0042] In some embodiments, the material of the top cooler of the vacuum stripping column is a corrosion-resistant material. Further, the corrosion-resistant material includes graphene. Graphene has excellent thermal conductivity, which can exchange heat faster; extremely high mechanical strength and toughness, which can better withstand vibration and external forces; and excellent corrosion resistance to chemicals such as acids, alkalis, and salts, and is not easily affected by corrosion. A condenser made of graphene material is selected. Compared with heat exchangers of other materials, it has better corrosion resistance and longer service life, ensuring the long-term stable operation of the device.

[0043] Figure 2 The structural schematic diagram of the system provided by the embodiments of the present application is as Figure 2 shown. Based on a general inventive concept, the embodiments of the present application also provide a preparation system for decoking and refining C5 petroleum resin to slow down corrosion. Using the method described in the first aspect, the system includes:

[0044] An atmospheric stripping column for performing atmospheric stripping on the crude resin oil;

[0045] A vacuum stripping column for performing vacuum stripping on the bottom liquid of the atmospheric stripping column. The vacuum stripping column is connected to the bottom of the atmospheric stripping column to receive the bottom liquid generated by the atmospheric stripping;

[0046] A feed pipeline for supplying the crude resin oil. The feed pipeline is connected to the middle of the atmospheric gas column;

[0047] The first corrosion inhibitor supply pipeline, which is connected between the tower body of the atmospheric stripper and the overhead cooler;

[0048] The second corrosion inhibitor supply pipeline, which is connected between the tower body of the vacuum stripper and the overhead cooler.

[0049] This system is implemented based on the above method. For the specific steps of the method, reference can be made to the above embodiments. Since this system adopts some or all of the technical solutions of the above embodiments, it at least has all the beneficial effects brought by the technical solutions of the above embodiments, which will not be elaborated one by one here.

[0050] In some embodiments, the material of the overhead cooler of the vacuum stripping includes graphene. Graphene has excellent thermal conductivity, which can exchange heat faster; extremely high mechanical strength and toughness, which can better withstand vibration and the influence of external forces; and excellent corrosion resistance to chemicals such as acids, alkalis, and salts, and is not easily affected by corrosion. A condenser made of graphene material is selected. Compared with heat exchangers of other materials, it has better corrosion resistance and a longer service life, ensuring the long-term stable operation of the device.

[0051] In this application, before the phase change occurs at the top of the tower, a liquid-phase corrosion inhibitor is injected to neutralize the acidic substances and chloride ions in the feed in the condenser, thereby reducing the corrosion of the equipment pipeline on the conveying medium; a material resistant to chloride ion corrosion is used for the condenser where the phase change occurs to provide a reaction site, thereby slowing down the corrosion of the subsequent equipment pipeline. By comprehensively adopting the above two measures, the long-term stable operation of the stripping and refining system is finally realized.

[0052] The following further elaborates this application in combination with specific embodiments. It should be understood that these embodiments are only used to illustrate this application and not to limit the scope of this application. For the experimental methods without specific conditions noted in the following embodiments, they are usually determined according to national standards. If there is no corresponding national standard, they are carried out according to general international standards, conventional conditions, or the conditions recommended by the manufacturer.

[0053] Example 1

[0054] A preparation method for decoking and refining of C5 petroleum resin to slow down corrosion, the method includes:

[0055] Using isoprene, monoolefins, etc. separated from ethylene cracking C5 as raw materials, under a certain ratio of monoene to diene, through the action of the catalyst aluminum trichloride, a cationic polymerization reaction occurs to generate a polymerization liquid, and the polymerization liquid enters the washing and sedimentation unit to remove the residual catalyst to obtain crude resin oil;

[0056] The crude resin oil is subjected to solvent removal and refining in a solvent removal and refining unit to finally obtain C5 petroleum resin. The solvent removal and refining includes atmospheric stripping and vacuum stripping. An inhibitor is injected during the atmospheric stripping and vacuum stripping to reduce pipeline corrosion, and the inhibitor is a liquid-phase inhibitor. The injection time of the liquid-phase inhibitor is before the steam liquefaction phase change occurs during the atmospheric stripping and vacuum stripping. The material of the overhead cooler in the vacuum stripping is carbon steel.

[0057] Example 2

[0058] A preparation method for solvent removal and refining of C5 petroleum resin for corrosion mitigation, the method comprising:

[0059] Using isoprene, monoolefins, etc. separated from ethylene pyrolysis C5 as raw materials, under a certain ratio condition of monoolefin and diolefin, through the action of catalyst aluminum trichloride, a cationic polymerization reaction occurs to generate a polymerization liquid, and the polymerization liquid enters a washing and sedimentation unit to remove the residual catalyst to obtain crude resin oil;

[0060] The crude resin oil is subjected to solvent removal and refining in a solvent removal and refining unit to finally obtain C5 petroleum resin. The solvent removal and refining includes atmospheric stripping and vacuum stripping. An inhibitor is injected during the atmospheric stripping and vacuum stripping to reduce pipeline corrosion, and the inhibitor is a liquid-phase inhibitor. The injection time of the liquid-phase inhibitor is before the steam liquefaction phase change occurs during the atmospheric stripping and vacuum stripping. The material of the overhead cooler in the vacuum stripping is carbon steel, and its surface is sprayed with a fluorine layer.

[0061] Example 3

[0062] A preparation method for solvent removal and refining of C5 petroleum resin for corrosion mitigation, the method comprising:

[0063] Using isoprene, monoolefins, etc. separated from ethylene pyrolysis C5 as raw materials, under a certain ratio condition of monoolefin and diolefin, through the action of catalyst aluminum trichloride, a cationic polymerization reaction occurs to generate a polymerization liquid, and the polymerization liquid enters a washing and sedimentation unit to remove the residual catalyst to obtain crude resin oil;

[0064] The crude resin oil is subjected to solvent removal and refining in a solvent removal and refining unit to finally obtain C5 petroleum resin. The solvent removal and refining includes atmospheric stripping and vacuum stripping. An inhibitor is injected during the atmospheric stripping and vacuum stripping to reduce pipeline corrosion, and the inhibitor is a liquid-phase inhibitor. The injection time of the liquid-phase inhibitor is before the steam liquefaction phase change occurs during the atmospheric stripping and vacuum stripping. The material of the overhead cooler in the vacuum stripping is graphene.

[0065] Comparative Example 1

[0066] A preparation method for solvent removal and refining of C5 petroleum resin for corrosion mitigation, the method comprising:

[0067] Using piperylene, monoolefins, etc. separated from ethylene cracking C5 as raw materials, under certain conditions of the ratio of monoolefins to diolefins, through the action of the catalyst aluminum trichloride, a cationic polymerization reaction occurs to generate a polymerization solution, and the polymerization solution enters the washing and sedimentation unit to remove the residual catalyst to obtain crude resin oil;

[0068] The crude resin oil is subjected to solvent and small molecule polymer removal in the solvent removal and refining unit to finally obtain C5 petroleum resin. The solvent removal and refining include atmospheric stripping and vacuum stripping, and an inhibitor is injected in the atmospheric stripping and vacuum stripping to reduce pipeline corrosion, and the inhibitor is ammonia. The injection timing of ammonia is before the steam liquefaction phase change in the atmospheric stripping and vacuum stripping. The material of the top cooler of the vacuum stripper is graphene.

[0069] The condenser replacement cycles of the methods provided in Examples 1 to 3 and Comparative Example 1 are shown in the following table:

[0070]

[0071] It can be seen from the above table that by using the method provided in the embodiment of the present application to prepare C5 petroleum resin, the corrosion of the pipeline can be slowed down and the overhaul and replacement cycle of the equipment can be extended.

[0072] The various embodiments of the present application may exist in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be construed as a rigid limitation on the scope of the present application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single values within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within that range, such as 1, 2, 3, 4, 5, and 6, which applies regardless of the range. Additionally, whenever a numerical range is indicated herein, it means including any cited number (fraction or integer) within the indicated range.

[0073] In this application, in the description of the specification of this application, the terms "including", "comprising", etc. mean "including but not limited to". In this text, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In this text, "at least one" means one or more, and "a plurality" means two or more. "At least one kind", "at least one (item) of the following" or similar expressions refer to any combination of these items, including any combination of single item(s) or plural item(s). For example, "at least one (item) of a, b, or c", or, "at least one (item) of a, b, and c" can both represent: a, b, c, a - b (i.e., a and b), a - c, b - c, or a - b - c, where a, b, and c can be single or multiple respectively.

[0074] The above are only specific embodiments of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application will not be limited to these embodiments shown herein, but rather will conform to the broadest scope consistent with the principles and novel features claimed herein.

Claims

1. A preparation method for desolventizing and refining C5 petroleum resin to slow down corrosion, characterized in that, the method includes: obtaining crude resin oil; performing desolventizing and refining on the crude resin oil to obtain C5 petroleum resin; wherein, the desolventizing and refining includes atmospheric stripping and vacuum stripping, and an inhibitor is injected during the atmospheric stripping and vacuum stripping to reduce pipeline corrosion, and the inhibitor is a liquid-phase inhibitor.

2. The preparation method for desolventizing and refining C5 petroleum resin to slow down corrosion according to claim 1, characterized in that, the liquid-phase inhibitor includes organic ammonia.

3. The preparation method for desolventizing and refining C5 petroleum resin to slow down corrosion according to claim 1 or 2, characterized in that, the injection timing of the liquid-phase inhibitor is before the steam liquefaction phase change occurs in the atmospheric stripping and vacuum stripping.

4. The preparation method for desolventizing and refining C5 petroleum resin to slow down corrosion according to claim 3, characterized in that, the feed rate of the crude resin oil is 6.4 - 9.6 t / h, and the dosage of the inhibitor is 0.8 - 1.5 kg / h.

5. The preparation method for desolventizing and refining C5 petroleum resin to slow down corrosion according to claim 3, characterized in that, the feed rate of the crude resin oil is 9.6 - 14.4 t / h, and the dosage of the inhibitor is 1 - 2 kg / h.

6. The preparation method for desolventizing and refining C5 petroleum resin to slow down corrosion according to claim 3, characterized in that, the feed rate of the crude resin oil is 12.8 - 19.2 t / h, and the dosage of the inhibitor is 1.5 - 3 kg / h.

7. The preparation method for desolventizing and refining C5 petroleum resin to slow down corrosion according to claim 3, characterized in that, the material of the top cooler of the vacuum stripper is a corrosion-resistant material.

8. The preparation method for desolventizing and refining C5 petroleum resin to slow down corrosion according to claim 3, characterized in that, the corrosion-resistant material includes graphene.

9. A preparation system for desolventizing and refining C5 petroleum resin to slow down corrosion, characterized in that, adopting the method according to any one of claims 1 to 8, and the system includes: an atmospheric stripper for performing atmospheric stripping on the crude resin oil; a vacuum stripper for performing vacuum stripping on the bottom liquid of the atmospheric stripper, and the vacuum stripper is connected to the bottom of the atmospheric stripper to receive the bottom liquid generated by the atmospheric stripping; a feed pipeline for supplying the crude resin oil, and the feed pipeline is connected to the middle part of the atmospheric gas tower; a first inhibitor supply pipeline, and the first inhibitor supply pipeline is connected between the tower body and the top cooler of the atmospheric stripper; a second inhibitor supply pipeline, and the second inhibitor supply pipeline is connected between the tower body and the top cooler of the vacuum stripper.

10. The preparation system for desolventizing and refining C5 petroleum resin to slow down corrosion according to claim 9, characterized in that, the material of the top cooler of the vacuum stripper includes graphene.

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