A cleaning system and method for vacuum pump deposits in a papermaking process

Abstract

The present invention relates to a cleaning system and method for deposits in a vacuum pump used in a papermaking process, belonging to the papermaking field. The implemented system includes a cleaning agent barrel, a papermaking circulating water tank, a first three-way valve, a pH regulator, a second three-way valve, a heat exchanger, a vacuum pump, and a gas-liquid separator. The cleaning agent barrel is connected to the inlet of the first three-way valve, the papermaking circulating water tank is connected to the inlet of the first three-way valve, the first three-way valve is connected to the inlet of the second three-way valve, the pH regulator is connected to the inlet of the second three-way valve, the second three-way valve is connected to the inlet of the heat exchanger, the outlet of the heat exchanger is connected to the inlet of the vacuum pump, the suction port of the vacuum pump is connected to the external atmosphere, the exhaust port of the vacuum pump is connected to the gas-liquid separator, and the outlet of the gas-liquid separator is connected to the papermaking circulating water tank. The method includes: temperature-controlled mixing, pumping to the vacuum pump, temperature control, impeller rotation and dispersion, pH value adjustment, and gas-liquid separation and recovery. The present invention can solve the problem of deposition and scaling in the vacuum pump body, thereby reducing the load of the vacuum pump and reducing power waste.

Description

Technical Field

[0001] The present invention relates to the field of papermaking, and particularly to a cleaning system and method for deposits of a vacuum pump used in a papermaking process. Background Art

[0002] The papermaking industry is a major energy consumer, and electricity consumption is one of its resource consumptions. Saving resources is the requirement of building a resource-saving and environment-friendly society. How to reduce resource waste is also a test faced by the papermaking industry. With the improvement of environmental awareness, energy conservation and emission reduction are also the foundation for the sustainable development of the papermaking industry.

[0003] The water ring vacuum system needs to be sealed with water, and these waters often contain substances such as carbonates, sulfates, silicates, etc. that are prone to deposit and scale. The scale formed is easily attached to the vacuum pump impeller and the inner wall surface of the pump. The accumulation of scale in the pump will increase the energy consumption of the vacuum pump by 20% - 30%, and even cause the rotor in the vacuum pump to lock up, which not only increases the charge burden but also increases the production failure risk, and does not conform to the growing concept of energy conservation and emission reduction.

[0004] The deposit control cleaner is a water-soluble substance containing polycarboxylate, which can wrap the cation surface separated from carbonates, sulfates, and silicates in the system, so that it cannot combine with anions to form salts that are easy to deposit, effectively preventing and dispersing carbonates, sulfates, silicates, etc., preventing them from depositing on the inner part of the pipeline and the surface of the equipment, and can slow down their crystal formation, thus effectively preventing the formation of scale and being able to disperse the scale that has already been generated, thereby reducing the vacuum pump load and reducing power waste. Summary of the Invention

[0005] In order to overcome the defects of the prior art, the technical problem to be solved by the present invention is to provide a cleaning system and method for deposits of a vacuum pump used in a papermaking process to solve the problem of deposition and scaling in the vacuum pump body.

[0006] To achieve this purpose, the present invention adopts the following technical solutions:

[0007] A cleaning system for the deposits of a vacuum pump used in a papermaking process, comprising a cleaning agent barrel, a papermaking circulating water tank, a first three-way valve, a pH regulator, a second three-way valve, a heat exchanger, a vacuum pump and a gas-liquid separator. The outlet of the cleaning agent barrel is connected to the first inlet of the first three-way valve through a first pipeline, the outlet of the papermaking circulating water tank is connected to the second inlet of the first three-way valve through a second pipeline, the outlet of the first three-way valve is connected to the first inlet of the second three-way valve through a third pipeline, the outlet of the pH regulator is connected to the second inlet of the second three-way valve through a fourth pipeline, the outlet of the second three-way valve is connected to the inlet of the heat exchanger through a fifth pipeline, the outlet of the heat exchanger is connected to the working fluid inlet of the vacuum pump through a sixth pipeline, the suction port of the vacuum pump is connected to the external atmosphere, the exhaust port of the vacuum pump is connected to the inlet of the gas-liquid separator through a seventh pipeline, and the liquid outlet of the gas-liquid separator is connected to the inlet of the papermaking circulating water tank through an eighth pipeline.

[0008] The preferred technical solution of the present invention lies in that it includes a filter, and the filter is arranged in the fifth pipeline.

[0009] The preferred technical solution of the present invention lies in that the inner wall of the fifth pipeline is provided with a mixing fin and a baffle structure.

[0010] The preferred technical solution of the present invention lies in that it includes a first metering pump, and the first metering pump is arranged in the first pipeline.

[0011] The preferred technical solution of the present invention lies in that an anion exchange membrane is arranged inside the gas-liquid separator.

[0012] The preferred technical solution of the present invention lies in that a liquid level control device is arranged inside the cleaning agent barrel.

[0013] A cleaning method for the deposits of a vacuum pump used in a papermaking process provided by the present invention comprises the following steps:

[0014] S00: A polycarboxylate cleaning agent is mixed with the circulating water in the papermaking circulating water tank to form a first type of mixed liquid, and the inlet temperature of the first type of mixed liquid is controlled at 25-30 °C;

[0015] S10: The first type of mixed liquid is pumped into the vacuum pump for cleaning and forming a water ring vacuum. The temperature inside the pump of the vacuum pump is controlled at 50-60 °C, and the pH value is adjusted by adding a 10% dilute sulfuric acid solution or a 10% sodium hydroxide solution, and the adjusted pH value is controlled at 6.5-7.5;

[0016] S20: The impeller of the vacuum pump rotates to make the first type of mixed liquid fully mixed and dispersed;

[0017] S30: The first type of mixed liquid is output to the gas-liquid separation device along with the gas of the vacuum pump;

[0018] S40: After being separated by the gas-liquid separator, the first type of mixed liquid enters the papermaking circulating water tank for internal circulation.

[0019] The preferred technical solution of the present invention is that in step S10, the first type of mixed liquid is first pumped into a filter to filter the impurities in the circulating water itself. After filtration, the filtered first type of mixed liquid is then pumped into a vacuum pump.

[0020] The preferred technical solution of the present invention is that in step S20, the first rotation running time of the first type of mixed liquid in the vacuum pump is more than 0.5 hours.

[0021] The preferred technical solution of the present invention is that the volume fraction of the polycarboxylate cleaner in the first type of mixed liquid is 0.05% - 0.3%.

[0022] The beneficial effects of the present invention:

[0023] The present invention adopts a brand-new polycarboxylate-based alkaline deposit control technology. By adding a polycarboxylate deposit control agent to the vacuum pump circulating water system, it controls the pH value and temperature during the circulation process, inhibits the formation of scale and disperses the crystallized scale, and reduces the load of the vacuum pump, reducing power waste. The developed new product is more environmentally friendly and more power-saving. It saves 20 Kwh / T of paper in power consumption compared with the production plan before transformation, with a year-on-year decrease of 25%. It has a lower cost, better meets the requirements of environmental protection and the market, and is of great significance for occupying the packaging market. Description of the Drawings

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention 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, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0025] Figure 1 It is a schematic diagram of a cleaning system for vacuum pump deposits used in a papermaking process of the present invention

[0026] Figure 2 It is a process flow diagram of a cleaning method for vacuum pump deposits used in a papermaking process of the present invention.

[0027] In the figure:

[0028] 1. Cleaner barrel; 2. Papermaking circulating water tank; 3. First three-way joint; 4. pH regulator; 5. Second three-way joint; 6. Heat exchanger; 7. Vacuum pump; 8. Gas-water separator; 9. Filter; 10. First metering pump. Detailed Embodiments

[0029] The technical solution of the present invention will be further described below with reference to the accompanying drawings and through specific implementation methods.

[0030] See also Figure 1 In this embodiment, a system for cleaning vacuum pump deposits for a papermaking process is provided, comprising a detergent barrel 1, a papermaking circulating water pool 2, a first tee 3, a pH regulator 4, a second tee 5, a heat exchanger 6, a vacuum pump 7 and an air-water separator 8. The outlet of the detergent barrel 1 is connected to the first inlet of the first tee 3 through a first pipe, the outlet of the papermaking circulating water pool 2 is connected to the second inlet of the first tee 3 through a second pipe, the outlet of the first tee 3 is connected to the first inlet of the second tee 5 through a third pipe, the outlet of the pH regulator 4 is connected to the second inlet of the second tee 5 through a fourth pipe, the outlet of the second tee 5 is connected to the inlet of the heat exchanger 6 through a fifth pipe, the outlet of the heat exchanger 6 is connected to the working fluid inlet of the vacuum pump 7 through a sixth pipe, the air intake of the vacuum pump 7 is connected to the outside atmosphere, the exhaust port of the vacuum pump 7 is connected to the inlet of the air-water separator 8 through a seventh pipe, and the liquid outlet of the air-water separator 8 is connected to the inlet of the papermaking circulating water pool 2 through an eighth pipe. Among them, pumps are added to the first pipeline and the third pipeline as power sources, and pressure gauges and temperature meters are added to the pipelines to monitor whether the system operation process is stable, so as to ensure that the temperature of the first type of mixed liquid entering the vacuum pump 7 is between 25-30°C. In addition, a sampling port is set in front of the pipeline entering the vacuum pump 7, and regular sampling can be used to detect the pH range to prevent excessive acidity from corroding the inner wall of the pump and pipeline, thereby increasing the actual power consumption in disguise.

[0031] Preferably, a filter 9 is included, and the filter 9 is arranged in the fifth pipe. Two layers of filter screens are provided in the filter 9. The first layer of filter screen is responsible for isolating colloidal impurities, and silica gel colloidal matter is used for adsorption filtration through the compatibility principle. The second layer of filter screen is responsible for isolating anionic impurities, and the filter element uses strong acidic cationic fiber electrical interaction filtration. The temperature is controlled at 25-30°C to ensure a good barrier effect.

[0032] Preferably, a mixing fin and baffle structure is provided on the inner wall of the fifth pipe. When the fluid is fed into the fifth pipe, it first passes through a group of deflection baffles for interception and concentration, and is preliminarily mixed. Then, it passes through a group of reversing baffles to divide the material into multiple streams and perform multiple reversals. Then, it passes through another group of deflection baffles. In this way, after repeated interception and concentration, dispersion and reversal, the disturbance of the fluid is increased in conjunction with the mixing fins, so as to achieve the purpose of sufficient mixing and dispersion.

[0033] In order to accurately regulate the amount of detergent in the vacuum water circulation system, preferably, a first metering pump 10 is included, and the first metering pump 10 is arranged in the first pipeline.

[0034] In order to remove the anions carried out by the vacuum pump, preferably, an anion exchange membrane is provided inside the gas-water separator 8. Moreover, a filter screen is additionally provided inside the gas-water separator 8, and a 200-mesh stainless steel filter screen is used to filter the deposits carried out by the vacuum pump 7 to prevent blockage of the liquid pipeline.

[0035] In order to prevent insufficient cleaning agent required during the operation of the vacuum pump, preferably, a liquid level control device is provided inside the cleaning agent barrel 1, and the process personnel are notified to supplement the raw materials through an automatic alarm system.

[0036] Please refer to Figure 2 , a method for cleaning the deposits of a vacuum pump used in a papermaking process provided in this embodiment includes the following steps:

[0037] S00: A polycarboxylate cleaning agent is mixed with the circulating water in the papermaking circulating water tank to form a first type of mixed liquid, and the inlet temperature of the first type of mixed liquid is controlled at 25-30 °C. Among them, the selected polycarboxylate cleaning agent is a homopolymer of acrylic acid, a composite of a binary copolymer of acrylic acid and a second monomer, with an average molecular weight of about 50,000, and the carboxyl molecular weight of the polymer is about 3,500. In addition, there are other composite formulas for polycarboxylates, not limited to the simple binary composite for cost considerations. The circulating water in the papermaking circulating water tank is the white water generated during the papermaking process, and the circulating water is supplied to multiple systems of the papermaking process. The white water used has been cooled by a cooling tower cooling device before entering the circulating water tank;

[0038] S10: The first type of mixed liquid is pumped into the vacuum pump for cleaning and forming a water ring vacuum. The temperature inside the pump of the vacuum pump is controlled at 50-60 °C. The pH value is adjusted by adding a 10% dilute sulfuric acid or 10% sodium hydroxide solution, and the adjusted pH value is controlled at 6.5-7.5 to ensure the best complexing effect of the cleaning agent on the cations in the water body, thereby inhibiting the combination of cations and anions to form precipitates. Among them, temperature detection instruments are provided on the pipeline before entering the vacuum pump and on the vacuum pump, and an air-cooling device is provided beside the vacuum pump for cooling, with the focus on controlling the temperature inside the pump. Excessive temperature will affect the vacuum effect of the vacuum pump, resulting in a small vacuum degree and being unfavorable for the evaporation process of subsequent processes;

[0039] S20: The impeller of the vacuum pump rotates, making the first type of mixed liquid fully mixed and dispersed. The rotation of the impeller inside the vacuum pump makes the polycarboxylate cleaning agent in the first type of mixed liquid fully mixed with the circulating water, causing the first type of mixed liquid to impact the surface of the impeller and the inner wall surface of the vacuum pump. The polycarboxylate cleaning agent reacts with the carbonates, sulfates, silicates, etc. in the water and the scale on the surface of the impeller and the inner wall surface of the vacuum pump during this impact mixing process, playing a cleaning role;

[0040] S30: The first type of mixed liquid is output to the gas-liquid separation device along with the gas from the vacuum pump. Among them, the output gas-liquid mainly contains gas, and the proportion of the first type of mixed liquid is relatively low. The depressurized gas is discharged from the upper part of the gas-liquid separation device, and the first type of mixed liquid accumulates at the bottom of the gas-liquid separation device under the action of gravity to form a liquid seal.

[0041] S40: After being separated by the gas-liquid separation device, the first type of mixed liquid enters the circulating water pool and is reused as circulating water.

[0042] The cleaning method of the above steps can effectively prevent and disperse carbonates, sulfates, silicates, etc., prevent them from depositing on the inner part of the pipeline and the surface of the equipment, and can slow down their crystal formation. In this way, the generation of scale is effectively prevented, and the existing scale can be dispersed, thereby reducing the load on the vacuum pump and reducing the waste of electric energy. The sealing water in the vacuum pump body returns to the sealing water pool for recycling after gas-water separation.

[0043] Preferably, in step S10, the first type of mixed liquid is first pumped into a filter for filtration to mainly filter out impurities such as colloids and insoluble coarse fibers in the original circulating water. After filtration, the filtered first type of mixed liquid is then pumped into the vacuum pump.

[0044] Preferably, in step S20, the first type of mixed liquid rotates in the vacuum pump for at least 0.5 hours for the first time, which can remove the deposits formed during shutdown and make the startup run more smoothly.

[0045] Preferably, the volume fraction of the polycarboxylate cleaner in the first type of mixed liquid is 0.15%.

[0046] Based on the above preferred solutions, through actual production data, the power consumption is saved by 20 Kwh / T paper compared with the original, and the proportion decreases by 25% year-on-year.

[0047] The present invention is described by way of preferred embodiments. Those skilled in the art know that without departing from the spirit and scope of the present invention, various changes or equivalent replacements can be made to these features and embodiments. The present invention is not limited by the specific embodiments disclosed herein, and other embodiments falling within the scope of the claims of this application belong to the scope of protection of the present invention.

Claims

1. A cleaning system for the deposits of a vacuum pump used in a papermaking process, characterized in that: It includes a cleaning agent barrel (1), a papermaking circulating water tank (2), a first three-way joint (3), a pH regulator (4), a second three-way joint (5), a heat exchanger (6), a vacuum pump (7) and a gas-liquid separator (8); The outlet of the cleaning agent barrel (1) is connected to the first inlet of the first three-way joint (3) through a first pipeline, the outlet of the papermaking circulating water tank (2) is connected to the second inlet of the first three-way joint (3) through a second pipeline, the outlet of the first three-way joint (3) is connected to the first inlet of the second three-way joint (5) through a third pipeline, the outlet of the pH regulator (4) is connected to the second inlet of the second three-way joint (5) through a fourth pipeline, the outlet of the second three-way joint (5) is connected to the inlet of the heat exchanger (6) through a fifth pipeline, the outlet of the heat exchanger (6) is connected to the working fluid inlet of the vacuum pump (7) through a sixth pipeline, the suction port of the vacuum pump (7) is connected to the outside atmosphere, the exhaust port of the vacuum pump (7) is connected to the inlet of the gas-liquid separator (8) through a seventh pipeline, and the liquid outlet of the gas-liquid separator (8) is connected to the inlet of the papermaking circulating water tank (2) through an eighth pipeline; An anion exchange membrane is arranged inside the gas-liquid separator (8); It includes a filter (9); The filter (9) is arranged in the fifth pipeline; The inner wall of the fifth pipeline is provided with a mixing fin and a baffle structure; It includes a first metering pump (10); The first metering pump (10) is arranged in the first pipeline; A liquid level control device is arranged inside the cleaning agent barrel (1).

2. A cleaning method for the deposits of a vacuum pump used in a papermaking process according to the cleaning system of claim 1, characterized in that: S00: A polycarboxylate cleaning agent is mixed with the circulating water in the papermaking circulating water tank to form a first type of mixed liquid, and the inlet temperature of the first type of mixed liquid is controlled to be 25 - 30 °C; S10: The first type of mixed liquid is pumped into the vacuum pump for cleaning and forming a water ring vacuum. The temperature inside the pump of the vacuum pump is controlled to be 50 - 60 °C, and the pH value is adjusted by adding a 10% dilute sulfuric acid or 10% sodium hydroxide solution, and the adjusted pH value is controlled to be 6.5 - 7.5; S20: The impeller of the vacuum pump rotates, so that the first type of mixed liquid is fully mixed and dispersed; S30: The first type of mixed liquid is output to the gas-liquid separation device along with the gas of the vacuum pump; S40: After being separated by the gas-liquid separation device, the first type of mixed liquid enters the papermaking circulating water tank for internal circulation.

3. According to the cleaning method for the deposits of a vacuum pump used in a papermaking process of claim 2, characterized in that: In step S10, the first type of mixed liquid is first pumped into the filter to filter the impurities in the circulating water itself. After filtration, the filtered first type of mixed liquid is then pumped into the vacuum pump.

4. According to the cleaning method for the deposits of a vacuum pump used in a papermaking process of claim 2, characterized in that: In step S20, the first rotation operation time of the first type of mixed liquid by the vacuum pump is more than 0.5 hours.

5. The method for cleaning the vacuum pump deposit for the papermaking process according to claim 2, characterized in that: The volume fraction of the polycarboxylate cleaner in the first type of mixed liquid is 0.05% - 0.3%.

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