Phenol removal washing pump front mixed pressurization process and system

Abstract

This invention relates to the field of metallurgical coking technology, specifically to a pre-pump mixing and pressurization process and system for phenol removal and washing. This process pressurizes the primary and secondary continuous washing separation towers with inert gas, changing the traditional atmospheric pressure gravity flow outflow to pressurized outflow. Specifically, it includes: under pressurized conditions, controlling the oil-water separation interface of the two towers through neutral sodium phenolate flow regulating valves and alkaline sodium phenolate flow regulating valves respectively; and controlling the top outflow and level sealing of the towers through primary mixed component level regulating valves and washed mixed component level regulating valves. The system includes pressurized separation towers, gas supply pipelines, and matching regulating valves and automatic control instruments. This invention achieves automatic and precise control of the separation interface and outflow rate, significantly improving regulation sensitivity, while eliminating equipment such as alkaline sodium phenolate high-level tanks, simplifying the process, reducing investment and operating costs, and effectively improving production efficiency and control level.

Description

Technical Field

[0001] This invention relates to the field of metallurgical coking technology, specifically to a pre-pump mixing and pressurization process and system for phenol removal and washing. Background Technology

[0002] In the metallurgical coking industry, phenol removal washing of distillates is a crucial step in tar processing. Its purpose is to extract phenolic substances from the phenolic oil, naphthalene oil, or unwashed mixture obtained from tar distillation using NaOH alkaline solution. Taking the unwashed mixture as an example, after mixing with NaOH solution, the phenols react chemically with the alkali to form water-soluble sodium phenolate. Subsequent static separation allows for the separation of the phenol-removed oil phase (phenol-removed mixture) from the aqueous phase (sodium phenolate).

[0003] Currently, the processes for achieving the above-mentioned process are mainly divided into two types: pre-pump mixing and spray-type processes. The improved process of this invention is the pre-pump mixing process. In the existing typical phenol removal washing pre-pump mixing atmospheric pressure process, the unwashed mixture is mixed with alkaline sodium phenolate from the alkaline sodium phenolate high-level tank before the mixture is conveyed to the mixing pump. After being stirred and conveyed by the pump, it enters the primary continuous washing separation tower for static separation. The product neutral sodium phenolate is collected from the bottom of the tower, and the mixture collected from the top of the tower after primary washing is mixed with dilute alkali solution before the secondary continuous washing pump and enters the secondary continuous washing separation tower for secondary phenol removal. The alkaline sodium phenolate produced at the bottom of the secondary continuous washing separation tower needs to pass through the alkaline sodium phenolate tank, alkaline sodium phenolate pump, and alkaline sodium phenolate high-level tank before it can flow back to the front end of the system to mix with the unwashed mixture. The final washed mixture product is obtained at the top of the tower.

[0004] A significant drawback of this existing technology is that the entire separation system operates at atmospheric pressure, and the oil phase at the top of the primary and secondary washing separation towers and the aqueous phase at the bottom are both collected by gravity flow or full-flow method based on liquid level difference. To achieve a stable oil-water separation interface, the traditional process involves installing a liquid level regulator on the sodium phenolate pipeline and manually adjusting its full-flow height. This method has a low level of automation, relies on manual operation, and suffers from poor control precision and stability.

[0005] To improve automation, existing patents (such as authorization number CN109647005B) propose an improved scheme that regulates the separation interface by controlling the aqueous phase flow rate through a regulating valve. However, this scheme still does not solve the fundamental problem: because the separation tower operates at atmospheric pressure, there is insufficient back pressure upstream of the regulating valve, resulting in a small operating pressure differential and low flow regulation sensitivity. To achieve the required flow control, large-diameter valves are often required, which not only increases equipment costs but also makes precise and sensitive automatic control difficult to achieve, as the effective and stable operation of the regulating valve requires a certain pressure upstream of the valve. Summary of the Invention

[0006] To overcome the shortcomings of the prior art, the present invention provides a pre-pump mixing and pressurization process and system for phenol removal washing, which achieves automated control of product collection and separation interface adjustment by pressurizing the separation tower.

[0007] To achieve the above objectives, the present invention employs the following technical solution: A pre-pump mixing and pressurization process for phenol removal washing includes the following steps: S1: Pressurize the primary washing separation tower with inert gas; S2: After the first settling separation is completed in the continuous washing separation tower, neutral sodium phenolate is extracted through its bottom pipeline. The extraction flow rate is adjusted by the neutral sodium phenolate flow regulating valve installed on the pipeline to control the oil-water separation interface in the tower. S3: At the same time, a primary mixture is collected through the top pipe of the primary washing separation tower, and the liquid level is controlled by the primary mixture liquid level regulating valve installed on the pipe to regulate the outflow. S4: Pressurize the secondary continuous washing and separation tower with inert gas; S5: After the second settling separation is completed in the secondary continuous washing separation tower, alkaline sodium phenolate is extracted through its bottom pipeline. The extraction flow rate is adjusted by the alkaline sodium phenolate flow regulating valve installed on the pipeline to control the oil-water separation interface in the tower, and the extracted alkaline sodium phenolate is directly sent to the unwashed mixed part pipeline. S6: At the same time, the washed mixture is collected through the top pipeline of the secondary washing separation tower, and the liquid level is controlled by the liquid level regulating valve of the washed mixture installed on the pipeline to regulate the outflow.

[0008] Furthermore, in steps S1 and S4, the inert gas is nitrogen, and the pressurization pressure is controlled within the range of 0.1~0.4MPa.

[0009] Furthermore, the nitrogen gas is supplied by an external pipeline and is depressurized by passing through a first nitrogen gas self-regulating valve and a second nitrogen gas self-regulating valve before entering the separation tower.

[0010] Furthermore, the bypass pipe of the first nitrogen self-regulating valve is provided with a first flow limiting orifice plate, and the bypass pipe of the second nitrogen self-regulating valve is provided with a second flow limiting orifice plate. The flow limiting orifice plate is used to maintain a continuous small flow supply of nitrogen.

[0011] Furthermore, before step S2, the method includes the step of mixing the unwashed mixture with the alkaline sodium phenolate from step S5 before the mixture delivery pump, and then feeding it into the primary washing separation tower after stirring by the pump.

[0012] Furthermore, before step S5, the method includes the following steps: mixing the primary mixture from step S3 with the dilute alkaline solution before the inlet of the secondary continuous washing pump, and then sending the mixture into the secondary continuous washing separation tower after stirring by the pump.

[0013] Furthermore, in steps S2 and S5, the opening degree of the neutral sodium phenolate flow regulating valve and the alkaline sodium phenolate flow regulating valve is automatically controlled by a flow recording and regulating instrument based on the pre-calculated separation interface and the required residence time.

[0014] Furthermore, in steps S3 and S6, the opening degree of the primary mixture level regulating valve and the washed mixture level regulating valve is automatically controlled by a level recording and regulating instrument to maintain a constant liquid level in the tower.

[0015] A system for implementing the above-described phenol removal washing pre-pump mixing and pressurization process includes: A primary and secondary continuous washing separation tower; an inert gas supply pipeline for pressurizing the primary and secondary continuous washing separation towers; a neutral sodium phenolate collection pipeline connected to the bottom outlet of the primary continuous washing separation tower, on which a neutral sodium phenolate flow regulating valve is installed.

[0016] The top outlet of the primary washing and separation tower is connected to a primary mixed component collection pipeline, which is equipped with a primary mixed component level regulating valve. The primary mixed component collection pipeline is connected to the bottom inlet of the secondary washing and separation tower.

[0017] The bottom outlet of the secondary washing separation tower is connected to an alkaline sodium phenolate collection pipeline, which is equipped with an alkaline sodium phenolate flow regulating valve, and the alkaline sodium phenolate collection pipeline is directly connected to the unwashed mixed component pipeline.

[0018] The top outlet of the secondary washing and separation tower is connected to a washed mixture collection pipeline, which is equipped with a washed mixture level regulating valve.

[0019] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention pressurizes the primary and secondary continuous washing separation towers, changing the traditional gravity flow of the sodium phenolate pipeline at the bottom and the mixed component pipeline at the top of the tower to pressurized flow. This provides a stable inlet pressure for the regulating valves on the pipelines, completely solving the bottleneck problem of low valve regulation sensitivity in atmospheric pressure systems. This enables high-precision, rapid-response automatic control of flow rate and liquid level using regulating valves, laying a solid foundation for the automation of the entire process.

[0020] 2. Significantly simplifies the process and reduces equipment investment and operating costs. In existing technologies, basic sodium phenolate requires the gravitational potential energy of an elevated tank to mix with the unwashed components, resulting in a lengthy process and numerous pieces of equipment. In this invention, because the secondary washing separation tower itself is pressurized, the basic sodium phenolate collected from the bottom of the tower can be directly transported to the mixing component transfer pump by pressure, completely eliminating the need for the high-level tank, the basic sodium phenolate tank, and the transfer pump. This not only simplifies the process and directly reduces the initial investment cost of equipment, but also reduces the plant floor space and saves long-term energy consumption and maintenance costs due to the reduction in power equipment (pumps).

[0021] 3. Improved production efficiency and system processing capacity. In atmospheric pressure gravity flow systems, fluid velocity is slow and pipe diameter is large. By changing the extraction method to pressurized outflow, the fluid velocity in the pipe is significantly increased. Under the premise of conveying the same flow rate of material, smaller diameter pipes and valves can be selected, reducing material costs. At the same time, the faster flow rate also reduces the residence time of material in the system, which is conducive to improving the unit time processing capacity (i.e., production efficiency) of the entire device.

[0022] 4. Improved ease of operation and system stability. This invention employs a closed-loop control system consisting of a pressure regulating valve and a level / flow regulating instrument, replacing the traditional manual adjustment of the liquid level regulator's full-flow height. This significantly reduces the labor intensity and skill requirements for operators, preventing deterioration of separation effects due to improper human operation. Simultaneously, the nitrogen pressurization system and its bypass flow-limiting orifice plate ensure constant pressure within the tower, creating optimal conditions for stable static separation, thereby guaranteeing the stability of the product quality of the neutral sodium phenolate and the washed mixture.

[0023] In summary, this invention, through the core improvement of "pressurization," has synergistically triggered a series of positive technical effects, including improved control precision, process flow, equipment investment, and operational efficiency, thereby comprehensively enhancing the technical level and economic benefits of the phenol removal and washing process. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure and process principle of the present invention.

[0025] The diagram shows the following markings: 1. Primary continuous washing separation tower; 2. Secondary continuous washing separation tower; 3. Alkali mixing tank; 4. Mixed component transfer pump; 5. Secondary continuous washing pump; 6. Dilute alkali pump; 7. Unwashed mixed component flow regulating valve; 8. Neutral sodium phenolate flow regulating valve; 9. Primary mixed component level regulating valve; 10. Alkaline sodium phenolate flow regulating valve; 11. First nitrogen self-regulating valve; 12. Second nitrogen self-regulating valve; 13. First pressure regulating valve; 14. Second pressure regulating valve; 15. Dilute alkali flow regulating valve; 16. First flow limiting orifice plate; 17. Second flow limiting orifice plate; 18. Washed mixed component level regulating valve; PRC, pressure recording and regulating instrument; LRC, level recording and control instrument; FRC, flow recording and regulating instrument. Detailed Implementation

[0026] The embodiments of the present invention are described in detail below. To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0028] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0029] In the description of this invention, it should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0030] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0031] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0032] like Figure 1 As shown, the pre-pump mixing and pressurization system for phenol removal washing provided by the present invention mainly includes a primary continuous washing separation tower 1, a secondary continuous washing separation tower 2, an alkali mixing tank 3, a mixing component conveying pump 4, a secondary continuous washing pump 5, and a dilute alkali pump 6.

[0033] The bottom outlet of the continuous washing separation tower 1 is connected to a neutral sodium phenolate collection pipeline. A neutral sodium phenolate flow regulating valve 8 is installed on the pipeline, and the neutral sodium phenolate flow regulating valve 8 is electrically connected to the flow recording and regulating instrument FRC02.

[0034] The top outlet of the primary washing separation tower 1 is connected to a primary mixed component collection pipeline. A secondary washing pump 5 and a primary mixed component level regulating valve 9 are installed on this pipeline. The primary mixed component level regulating valve 9 is electrically connected to the level recording and control instrument LRC01. The primary mixed component collection pipeline is connected to the bottom inlet of the secondary washing separation tower 2.

[0035] The alkali mixing tank 3 is connected to the primary mixing component extraction pipeline, and the connected pipeline is equipped with a dilute alkali pump 6 and a dilute alkali flow regulating valve 15. The dilute alkali flow regulating valve 15 is electrically connected to the flow recording and regulating instrument FRC04.

[0036] The other top outlet of the continuous washing and separation tower 1 is connected to the exhaust gas washing tower pipeline, and a first pressure regulating valve 13 is installed on the connected pipeline. The first pressure regulating valve 13 is electrically connected to the pressure recording and regulating instrument PRC01.

[0037] The unwashed mixed component pipeline is connected to the bottom inlet pipeline of the primary washing separation tower 1, and the connected pipeline is equipped with a mixed component transfer pump 4 and an unwashed mixed component flow regulating valve 7. The unwashed mixed component flow regulating valve 7 is electrically connected to the flow recording and regulating instrument FRC01.

[0038] The bottom outlet of the secondary continuous washing separation tower 2 is connected to an alkaline sodium phenolate collection pipeline. An alkaline sodium phenolate flow regulating valve 10 is installed on the pipeline, and the alkaline sodium phenolate collection pipeline is directly connected to the unwashed mixed part pipeline. The alkaline sodium phenolate flow regulating valve 10 is electrically connected to the flow recording and regulating instrument FRC03.

[0039] The top outlet of the secondary washing separation tower 2 is connected to a washed mixed component collection pipeline. A washed mixed component level regulating valve 18 is installed on the pipeline, and the washed mixed component level regulating valve 18 is electrically connected to the level recording and control instrument LRC02.

[0040] The other top outlet of the secondary continuous washing and separation tower 2 is connected to the tail gas to exhaust gas washing tower pipeline, and a second pressure regulating valve 14 is installed on the connected pipeline. The second pressure regulating valve 14 is electrically connected to the pressure recording and regulating instrument PRC02.

[0041] To achieve pressurization, the system is equipped with an inert gas supply pipeline (nitrogen is used as an example in this embodiment). This pipeline is divided into two paths: one path enters the primary continuous washing separation tower 1 after being depressurized by the first nitrogen self-regulating valve 11, and the other path enters the secondary continuous washing separation tower 2 after being depressurized by the second nitrogen self-regulating valve 12. To ensure pressure stability, a bypass with a first flow limiting orifice plate 16 is connected in parallel next to the first nitrogen self-regulating valve 11, and a bypass with a second flow limiting orifice plate 17 is connected in parallel next to the second nitrogen self-regulating valve 12. The pressures of the primary continuous washing separation tower 1 and the secondary continuous washing separation tower 2 are controlled by the first pressure regulating valve 13 and the second pressure regulating valve 14, respectively.

[0042] Based on the above system, the pre-pump mixing and pressurization process for phenol removal washing in this invention is as follows: 1. System pressurization and pressure control: The system is started, and the incoming 0.4MPa nitrogen gas is divided into two streams. One stream is depressurized to approximately 0.1MPa by the first nitrogen self-regulating valve 11 and then enters the primary continuous washing separation tower 1; the other stream is similarly depressurized by the second nitrogen self-regulating valve 12 and then enters the secondary continuous washing separation tower 2. Through a closed-loop control system consisting of the first pressure regulating valve 13 and the pressure recording and regulating instrument PRC01, the operating pressure of the primary continuous washing separation tower 1 is stably controlled at 0.11MPa (which can be set within the range of 0.1~0.4MPa). Similarly, the pressure of the secondary continuous washing separation tower 2 is stabilized at the same level through the second pressure regulating valve 14 and PRC02. The first and second flow limiting orifice plates 16 and 17, located on the bypasses of the first and second nitrogen self-regulating valves, ensure a continuous small flow of nitrogen to enhance the stability of the pressure within the towers.

[0043] 2. Single-stage phenol removal washing and automated extraction: Feeding and Reaction: The unwashed mixture is mixed with the basic sodium phenolate coming directly from the bottom of the secondary washing separation tower 2 before the mixture transfer pump 4. The flow rate of the basic sodium phenolate is controlled by the flow recorder and regulator FRC03.

[0044] After being stirred by the mixing pump 4, the mixture enters the pressurized primary washing separation tower 1 for the first static separation. The flow rate of the mixture is adjusted by the unwashed mixed part flow regulating valve 7 (controlled by the flow record regulating instrument FRC01).

[0045] Bottom of the column (neutral sodium phenolate product): After separation, the neutral sodium phenolate generated at the bottom of the column is collected through the neutral sodium phenolate collection pipeline and the neutral sodium phenolate flow regulating valve 8 installed on it. A closed-loop flow control is formed by the flow recording and regulating instrument FRC02: Based on the pre-calculated flow value set by the separation interface and residence time, FRC02 automatically adjusts the opening of the neutral sodium phenolate flow regulating valve 8 to stabilize the collected flow rate of neutral sodium phenolate at the set value, thereby precisely controlling the oil-water separation interface within the column.

[0046] Top of the column (primary mixed portion): After separation, the primary mixed portion after primary washing at the top of the column is collected through the primary mixed portion collection pipeline and the primary mixed portion level regulating valve 9 located thereon. A closed-loop level control is established through the level recording and control instrument LRC01: LRC01 automatically adjusts the opening of the primary mixed portion level regulating valve 9 to maintain a constant liquid level in the primary washing separation column 1, thereby sealing the nitrogen gas inside the column and achieving a stable outflow of the product from the top of the column.

[0047] 3. Secondary phenol removal washing, circulation, and final extraction: Feeding and Secondary Reaction: The primary mixture sample taken from the top of the primary continuous washing separation tower 1 is mixed with a 10% NaOH dilute alkali solution delivered from the alkali preparation tank 3 via the dilute alkali pump 6. The flow rate of the dilute alkali solution is regulated by the dilute alkali flow regulating valve 15 (controlled by the flow recording and regulating instrument FRC04). The mixture is stirred and conveyed by the secondary continuous washing pump 5 and enters the pressurized secondary continuous washing separation tower 2 for a second settling separation.

[0048] Bottom-of-tower extraction and circulation (basic sodium phenolate): After separation, the basic sodium phenolate generated at the bottom of the tower is extracted through the basic sodium phenolate extraction pipeline and the basic sodium phenolate flow regulating valve 10 installed on it. A flow closed-loop control is established through the flow recording and regulating instrument FRC03: FRC03 automatically adjusts the opening of the basic sodium phenolate flow regulating valve 10 to stabilize the extracted flow rate of basic sodium phenolate at the set value, thereby controlling the oil-water separation interface within the tower. The extracted basic sodium phenolate no longer passes through the traditional high-level tank, but is directly transported through the pipeline and returned to the unwashed mixed portion pipeline by the pressure inside the tower, realizing the recycling of materials.

[0049] Top of the column (final product): After separation, the washed mixture (final product) at the top of the column is collected via the washed mixture collection pipeline and the washed mixture level regulating valve 18 located thereon. A closed-loop level control is established through the level recording and control instrument LRC02: LRC02 automatically adjusts the opening of the washed mixture level regulating valve 18 to maintain a constant liquid level in the secondary washing separation column 2, achieving nitrogen sealing and stable product collection. The collected washed mixture is sent to the industrial naphthalene distillation unit as raw material.

[0050] Through the close integration of the above system and process, the present invention successfully upgrades the phenol removal washing process from the traditional mode of atmospheric pressure, manual, and gravity flow to the advanced mode of pressurized, automatic, and forced outflow, which significantly improves control accuracy, production efficiency and operating economy.

[0051] The above description is only a part of the specific embodiments of the present invention. The scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A pre-pump mixing and pressurization process for phenol removal washing, characterized in that, Includes the following steps: S1: Pressurize the primary washing separation tower (1) with inert gas; the inert gas is nitrogen, and the pressurization pressure is controlled within the range of 0.1~0.4MPa; S2: After the first static separation is completed in the continuous washing separation tower (1), neutral sodium phenolate is extracted through the bottom pipeline of the tower. The extraction flow rate is adjusted by the neutral sodium phenolate flow regulating valve (8) set on the pipeline to control the oil-water separation interface in the tower. S3: At the same time, a primary mixed component is collected through the top pipe of the primary washing separation tower (1), and the liquid level is controlled by the primary mixed component liquid level regulating valve (9) installed on the pipe to regulate the outflow. S4: Pressurize the secondary continuous washing separation tower (2) with inert gas; the inert gas is nitrogen, and the pressurization pressure is controlled within the range of 0.1~0.4MPa; S5: After the second static separation is completed in the secondary continuous washing separation tower (2), the alkaline sodium phenolate is extracted through the bottom pipeline of the tower. The extraction flow rate is adjusted by the alkaline sodium phenolate flow regulating valve (10) set on the pipeline to control the oil-water separation interface in the tower and the extracted alkaline sodium phenolate is directly sent into the unwashed mixed part pipeline. S6: At the same time, the washed mixture is taken out through the top pipe of the secondary washing separation tower (2), and the liquid level is controlled by the liquid level regulating valve (18) of the washed mixture installed on the pipe to regulate the outflow.

2. The pre-pump mixing and pressurization process for phenol removal washing according to claim 1, characterized in that, The nitrogen gas is supplied by an external pipeline and is depressurized by passing through a first nitrogen gas self-regulating valve (11) and a second nitrogen gas self-regulating valve (12) before entering the separation tower.

3. The pre-pump mixing and pressurization process for phenol removal washing according to claim 2, characterized in that, The bypass pipe of the first nitrogen self-regulating valve (11) is provided with a first flow limiting orifice plate (16), and the bypass pipe of the second nitrogen self-regulating valve (12) is provided with a second flow limiting orifice plate (17). The flow limiting orifice plate is used to maintain a continuous small flow supply of nitrogen.

4. The pre-pump mixing and pressurization process for phenol removal washing according to claim 1, characterized in that, Before step S2, the process also includes the step of mixing the unwashed mixture with the alkaline sodium phenolate from step S5 in front of the mixture transfer pump (4), and then sending it into the primary washing separation tower (1) after being stirred by the pump.

5. The pre-pump mixing and pressurization process for phenol removal washing according to claim 1, characterized in that, Before step S5, the process also includes the step of mixing the primary mixture from step S3 with the dilute alkali solution before the inlet of the secondary continuous washing pump (5), and then sending it into the secondary continuous washing separation tower (2) after stirring by the pump.

6. The pre-pump mixing and pressurization process for phenol removal washing according to claim 1, characterized in that, In steps S2 and S5, the opening degree of the neutral sodium phenolate flow regulating valve (8) and the alkaline sodium phenolate flow regulating valve (10) is automatically controlled by a flow recording and regulating instrument based on the pre-calculated separation interface and the required residence time.

7. The pre-pump mixing and pressurization process for phenol removal washing according to claim 1, characterized in that, In steps S3 and S6, the opening degree of the primary mixed liquid level regulating valve (9) and the washed mixed liquid level regulating valve (18) is automatically controlled by the liquid level recording and regulating instrument to maintain a constant liquid level in the tower.

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