A water-saving device

Abstract

This application discloses a water-saving device in the field of pulp production, including a light wastewater system, a filtrate conveying system, and a main reaction tower. The light wastewater system serves as a supplement to the filtrate conveying system, and its outlet is connected to the filtrate conveying system. The filtrate conveying system provides filtrate to the main reaction tower, and its outlet is connected to the main reaction tower. When replenishing washing liquid for the EOP (Exhaust Operating Procedure) section, the water-saving device provided in this solution can be used to connect the light wastewater from the light wastewater tank to the filtrate conveying system via a light wastewater conveying pipe, replacing the need for hot clean water replenishment. This reduces wastewater discharge and ultimately lowers the consumption of hot clean water in the EOP section.

Description

Technical Field

[0001] This application relates to the field of pulp production, and in particular to a water-saving device. Background Technology

[0002] Bleached sulfate pulping is a cornerstone process for producing high-brightness, high-strength pulp and manufacturing high-end paper products. Its main process flow includes raw material pretreatment, cooking, screening, oxygen delignification, and bleaching, with an alkali recovery system. To meet pulp mills' demands for high-brightness, low-pollution pulp, the bleaching process primarily employs elemental chlorine-free bleaching (ECF bleaching), consisting of a high-temperature delignification stage (DHT), an extraction stage with oxygen and peroxide (EOP), a first chlorine dioxide bleaching stage (D1), and a second chlorine dioxide bleaching stage (D2). Stages DHT, D1, and D2 are ClO2 bleaching stages, while the EOP stage is an oxygen-enhanced alkali extraction stage.

[0003] To remove residual dissolved lignin, reaction byproducts, and residual chemicals from the pulp during the bleaching stage, and to reduce hot water consumption and wastewater treatment load, multi-stage countercurrent washing technology is typically used in production to dilute and wash the pulp. The D2 stage is the final bleaching stage, and the resulting filtrate has a low pH and is mainly used as the washing liquid for the D2, D1, and DHT stages. Therefore, it is necessary to supplement the EOP stage washing liquid to control the concentration and washing effect of the pulp in the EOP stage. However, this increases the hot water consumption during the bleaching stage and raises production costs.

[0004] Therefore, how to reduce the consumption of hot water in the EOP section is a problem that urgently needs to be solved by those skilled in the art. Utility Model Content

[0005] This application proposes a water-saving device designed to reduce the consumption of hot clean water in the EOP section by replacing hot clean water with light wastewater to replenish the washing liquid.

[0006] To achieve the above objectives, this application discloses the following technical solutions:

[0007] A water-saving device includes a light wastewater system, a filtrate delivery system, and a main reaction tower; the light wastewater system serves as a supplementary system to the filtrate delivery system, and its outlet is connected to the filtrate delivery system; the filtrate delivery system provides filtrate to the main reaction tower, and its outlet is connected to the main reaction tower.

[0008] In some embodiments, the light wastewater system includes a light wastewater tank, a light wastewater pump, a light wastewater delivery control valve, a light wastewater delivery pipe, and a light wastewater flow control valve;

[0009] One end of the light wastewater conveying pipe is connected to the light wastewater tank, and the other end of the light wastewater conveying pipe is connected to the filtrate conveying system.

[0010] The light wastewater pump and light wastewater transport control valve are located on the light wastewater transport pipe and at one end close to the light wastewater tank;

[0011] The light wastewater flow control valve is located on the light wastewater delivery pipe and at one end near the filtrate delivery system.

[0012] In some embodiments, the filtrate delivery system includes a filtrate tank, a filtrate delivery pipe, a filtrate pressurization pump, and a filtrate delivery control valve;

[0013] One end of the filtrate delivery pipe is connected to the filtrate tank, and the other end of the filtrate delivery pipe is connected to the main reaction tower.

[0014] The filtrate pressurization pump and filtrate delivery control valve are located on the filtrate delivery pipe and at one end near the filtrate tank.

[0015] In some embodiments, the light wastewater conveying pipe is connected to the filtrate conveying pipe, and the distance between the connection point and the filtrate tank is 1m-1.5m.

[0016] In some embodiments, the light wastewater system also includes a conductivity meter installed on the light wastewater delivery pipe, and the distance between the light wastewater delivery pipe and the connection point of the filtrate delivery pipe is less than 1m.

[0017] In some embodiments, the filtrate delivery system further includes a hot clean water supply component, which includes a hot clean water supply pipe and a hot clean water supply valve. The hot clean water supply valve is located on the hot clean water supply pipe, and the hot clean water supply pipe is connected to the filtrate tank.

[0018] Some embodiments also include a control cabinet, with a light wastewater pump, a light wastewater delivery control valve, a light wastewater flow control valve, a conductivity meter, and a hot clean water supply valve electrically connected to the control cabinet.

[0019] In some embodiments, the filtrate delivery pipe includes at least two filtrate delivery branches connected to the main reaction tower, and each filtrate delivery branch is equipped with a filtrate delivery branch valve.

[0020] In some embodiments, the light wastewater system also includes a flow meter located on the light wastewater delivery pipe and between the light wastewater flow control valve and the light wastewater delivery control valve;

[0021] The flow meter is electrically connected to the control cabinet.

[0022] Some embodiments also include an insulation section located in the light wastewater system and the filtrate delivery system to ensure that the temperature of the light wastewater and filtrate is maintained at a set value.

[0023] As can be seen from the above technical solution, when replenishing the washing liquid for the EOP section, the water-saving device provided in this solution can be used to connect the light wastewater in the light wastewater tank to the filtrate delivery system through the light wastewater delivery pipe, in order to replace the hot clean water replenishment. This can reduce the discharge of wastewater system and ultimately achieve the goal of reducing the consumption of hot clean water in the EOP section. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some examples or embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort, and this application can be applied to other similar scenarios based on the provided drawings, all of which fall within the scope of protection of this utility model. Unless obvious from the linguistic context or otherwise specified, the same reference numerals in the drawings represent the same structure or operation.

[0025] Figure 1 This is a flowchart of a water-saving device provided in an embodiment of this application;

[0026] Among them, 10-water-saving device;

[0027] 100 - Light wastewater system; 200 - Filtrate delivery system; 300 - Main reaction tower;

[0028] 110 - Light wastewater tank; 120 - Light wastewater pump; 130 - Light wastewater transfer control valve; 140 - Light wastewater transfer pipe; 150 - Light wastewater flow control valve; 160 - Conductivity meter; 170 - Flow meter;

[0029] 210-Filtrate tank; 220-Filtrate pressurization pump; 230-Filtrate delivery control valve; 240-Filtrate delivery pipe; 241-Filtrate delivery branch pipe; 241a-Filtrate delivery branch pipe valve; 250-Hot clean water replenishment component; 251-Hot clean water replenishment pipe; 252-Hot clean water replenishment valve. Detailed Implementation

[0030] The present application will be further described in detail below in conjunction with the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the relevant application and do not limit the application. The described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts fall within the scope of protection of the present application.

[0031] In order to reduce the consumption of hot fresh water in the EOP section, the present application specifically introduces the structure of the water-saving device 10 in conjunction with the accompanying drawings:

[0032] See Figure 1 , the present application provides a water-saving device 10, including a light sewage system 100, a filtrate conveying system 200 and a main reaction tower 300; the light sewage system 100 serves as a supplementary system for the filtrate conveying system 200, and the outlet end of the light sewage system 100 is connected to the filtrate conveying system 200; the filtrate conveying system 200 provides filtrate for the main reaction tower 300, and the outlet end of the filtrate conveying system 200 is connected to the main reaction tower 300.

[0033] When supplementing the washing liquid for the EOP section, the water-saving device 10 provided by this solution can be adopted. The light sewage in the light sewage tank 110 is connected to the filtrate conveying system 200 through the light sewage conveying pipe 140 to replace the hot fresh water replenishment. This can reduce the discharge of the wastewater system and ultimately achieve the purpose of reducing the consumption of hot fresh water in the EOP section.

[0034] The function of the light sewage system 100 is to provide light sewage as the washing liquid for the filtrate conveying system 200. Before introducing the light sewage system 100, the concept of light sewage will be briefly introduced.

[0035] The alkali recovery system supporting the pulping process can realize the evaporation and concentration of the dilute black liquor. In this process, the dilute black liquor generates solids and water vapor (referred to as secondary steam) after heating in the effect body. The secondary steam is then used to heat the dilute black liquor in the next effect body and generates secondary condensate after condensation. According to the concentration of pollutants in the secondary condensate, it can be divided into three categories: heavy sewage, medium sewage and light sewage. Among them, light sewage has the characteristics of low conductivity (≤100 μS / cm), high temperature (60 - 80 °C) and alkaline pH (8 - 10), which is suitable for the alkaline washing environment in the EOP section and can be directly used as the washing liquid in the EOP section. The present application realizes the replacement of hot fresh water by introducing light sewage into the EOP filtrate tank 210, reduces the discharge of wastewater, reduces the consumption of hot fresh water in the EOP section, and thus reduces the production cost. It can be seen that the recycling of light sewage has significant advantages.

[0036] Next, the specific structure of the light sewage system 100 will be specifically introduced.

[0037] The light wastewater system 100 includes a light wastewater tank 110, a light wastewater pump 120, a light wastewater transport control valve 130, a light wastewater transport pipe 140, and a light wastewater flow control valve 150. The light wastewater transport pipe 140 serves as the connecting line for the entire light wastewater system 100, linking the other components together to achieve the transport of light wastewater. Due to the unique physical and chemical properties of the light wastewater medium being transported—high temperature (60-80℃) and alkaline pH (8-10)—a unique pipe material needs to be considered. In this embodiment, 304L stainless steel pipes are used. These pipes have excellent heat resistance, can cover the temperature range of light wastewater, have excellent alkali resistance, low overall cost, and are easy to install.

[0038] In some embodiments, in order to meet the requirements of equipment vibration, external impact, etc., the pipe material of the light sewage conveying pipe 140 needs to be changed to 316L stainless steel. Under the premise of meeting the requirements of light sewage high temperature and strong alkali, it also has the greatest advantage of high mechanical strength, fire resistance, pressure resistance and impact resistance, making it an excellent choice for the pipe material of the light sewage conveying pipe 140.

[0039] The function of the light wastewater tank 110 is to collect the light wastewater discharged from the alkali recovery system. Typically, the light wastewater tank 110 is a closed container responsible for holding the light wastewater and needs to be made of materials resistant to high temperatures and alkali corrosion, such as fiber reinforced plastic (FRP), 304L stainless steel, 316L stainless steel, or chlorinated polyvinyl chloride (CPVC). It should be noted that when the light wastewater tank 110 and the light wastewater delivery pipe 140 are made of the same material, their connection can be achieved through flange connection, hot-melt socket joint, welding, threaded connection, etc.

[0040] When the light sewage tank 110 is made of 304L stainless steel and the light sewage conveying pipe 140 is also made of 304L stainless steel, a 304L stainless steel flange interface can be pre-installed during the manufacturing process of the light sewage tank 110, which is integrated with the light sewage tank 110. The light sewage conveying pipe 140 has its own 304L stainless steel flange interface, or a 304L stainless steel flange interface can be welded onto the light sewage conveying pipe 140. The two are then connected and tightened with bolts. Alternatively, the light sewage tank 110 can only have a 304L stainless steel pipe interface pre-installed, and the light sewage conveying pipe 140 can be directly welded to the pipe interface.

[0041] Taking the light sewage tank 110 and the light sewage conveying pipe 140 as examples, during the manufacturing process of the light sewage tank 110, a CPVC flange interface integrated with the light sewage tank 110 can be reserved, and the light sewage conveying pipe 140 has its own CPVC flange interface. After the two are connected, they are tightened with bolts; or the light sewage tank 110 can reserve a CPVC pipe interface corresponding to the pipe diameter of the light sewage conveying pipe 140, and after the hot melt socket connection, an adhesive is applied to achieve a tight connection.

[0042] When the materials of the light sewage tank 110 and the light sewage conveying pipe 140 are different, a steel-plastic conversion joint is required for connection. A steel-plastic conversion joint is a standard part with a plastic interface, such as CPVC, on one end and a steel interface, such as 304L stainless steel, on the other end, with the intermediate transition part specially sealed by the supplier through injection molding.

[0043] Taking the light sewage tank 110 as being made of CPVC and the light sewage conveying pipe 140 as being made of 304L stainless steel as an example, the plastic interface of the steel-plastic conversion joint is connected to the light sewage tank 110, and the steel interface of the steel-plastic conversion joint is connected to the light sewage conveying pipe 140. The connection method can refer to the connection method of the same material pipe mentioned above, and will not be elaborated further here.

[0044] The structure of the light wastewater tank 110 and its connection with the light wastewater conveying pipe 140 have been introduced above. The functions of the light wastewater pump 120 and the light wastewater conveying control valve 130 will be introduced in detail below.

[0045] The function of the light wastewater pump 120 is to transport light wastewater from the light wastewater tank 110 to the filtrate delivery system 200 through the pump body. The function of the light wastewater delivery control valve 130 is to cooperate with the light wastewater pump 120 to control the opening and closing of the light wastewater delivery pipe 140. The light wastewater pump 120 and the light wastewater delivery control valve 130 are located on the light wastewater delivery pipe 140, and are located at one end closer to the light wastewater tank 110. The advantage of this arrangement is that it shortens the pipe length at the pump suction inlet, reduces the risk of cavitation at the suction inlet, and improves the working efficiency of the pump.

[0046] The light wastewater conveying control valve 130 has been introduced. Next, we will focus on introducing the light wastewater flow control valve 150.

[0047] Before introducing the light wastewater flow control valve 150, it's necessary to first introduce the conductivity meter 160 and the flow meter 170. The conductivity meter 160 measures the conductivity of the light wastewater, with a measurement cycle of once every 5 seconds, ensuring it remains within the range of less than or equal to 100 μS / cm. The flow meter 170 measures the volume of light wastewater passing through the light wastewater delivery pipe 140 per unit time; in this embodiment, the flow rate of the light wastewater is controlled at 30-40 L / s. The light wastewater flow control valve 150 automatically adjusts the valve opening to regulate the flow rate of the light wastewater.

[0048] Reference Figure 1The conductivity meter 160, flow meter 170, and light wastewater flow control valve 150 are also located on the light wastewater conveying pipe 140, but their installation positions are closer to the connection point between the light wastewater conveying pipe 140 and the filtrate conveying pipe 240. This facilitates monitoring the conductivity of the light wastewater that finally enters the filtrate conveying pipe 240, thereby adjusting the light wastewater flow rate. It should be noted that the distance between the installation position of the conductivity meter 160 and the connection point between the light wastewater conveying pipe 140 and the filtrate conveying pipe 240 is less than 1m.

[0049] When the conductivity of the light wastewater is less than or equal to 100 μS / cm, the light wastewater flow control valve 150 controls the opening, and the flow meter 170 monitors the flow rate to keep the light wastewater flow rate at 30-40 L / s. When the conductivity meter 160 detects that the conductivity of the light wastewater is greater than 100 μS / cm for three consecutive times, the opening of the light wastewater flow control valve 150 is reduced to increase the hot clean water replenishment. When the conductivity meter 160 detects that the conductivity of the light wastewater is greater than 150 μS / cm, the light wastewater delivery control valve 130 needs to be closed to cut off the water injection into the light wastewater system 100.

[0050] The light sewage pump 120, light sewage conveying control valve 130, light sewage flow control valve 150, conductivity meter 160, flow meter 170 and the above-mentioned light sewage pump 120 are all made of steel or metal. The connection between them and the light sewage conveying pipe 140 can refer to the connection between the same material or different materials mentioned above, which will not be elaborated on here.

[0051] The working principle and connection method of the light wastewater system 100 have been introduced above. Next, the structure and principle of the filtrate delivery system 200 will be introduced.

[0052] The filtrate delivery system 200 is designed to deliver filtrate to the main reaction tower 300. It primarily includes a filtrate tank 210, a filtrate delivery pipe 240, a filtrate pressurization pump 220, and a filtrate delivery control valve 230. The filtrate delivery pipe 240 serves as the connecting line for the entire filtrate delivery system 200, linking the other components together to achieve filtrate delivery. Since the physical and chemical properties of the filtrate are similar to those of light wastewater—both are high-temperature, alkaline substances—the filtrate delivery pipe 240 must be made of FRP, 304L stainless steel, or 316L stainless steel to meet the requirements of high temperature resistance, alkali resistance, and impact resistance.

[0053] The function of the filtrate tank 210 is to prepare and provide the washing liquid required for the EOP section washing. The material of the filtrate tank 210 is the same as that of the light wastewater tank 110, or it can be made of FRP, 304L stainless steel or 316L stainless steel, etc. The connection between the filtrate tank 210 and the filtrate delivery pipe 240 is the same as the connection between the same material or different materials mentioned above, and will not be elaborated on here.

[0054] In order to transport the filtrate from the filtrate tank 210 to the main reaction tower 300, one end of the filtrate delivery pipe 240 is connected to the filtrate tank 210, and the other end of the filtrate delivery pipe 240 is detachably connected to the main reaction tower 300, so that the filtrate delivery pipe 240 can be easily replaced and maintained.

[0055] Similar to the light wastewater pump 120 and the light wastewater transfer control valve 130, the filtrate booster pump 220 and the filtrate transfer control valve 230 are located on the filtrate transfer pipe 240 and are also located at one end close to the filtrate tank 210. The advantage of this is that it shortens the pipe length of the suction inlet of the filtrate booster pump 220, reduces the risk of cavitation at the suction inlet, and improves the working efficiency of the filtrate booster pump 220. The advantage of the light wastewater transfer control valve 130 being close to the filtrate tank 210 is that when the pump is stopped for maintenance, the light wastewater transfer control valve 130 can be shut off, resulting in a short distance between the light wastewater transfer control valve 130 and the filtrate tank 210, minimal water discharge, and convenient maintenance.

[0056] It should be noted that the light wastewater conveying pipe 140 is connected to the filtrate conveying pipe 240, and the distance between the connection point and the filtrate tank 210 is 1m-1.5m. (Reference) Figure 1 This position is located between the filtrate pressurization pump 220 and the filtrate tank 210, so that the outlet of the light wastewater conveying pipe 140 is located at the inlet of the filtrate pressurization pump 220, making the water flow direction consistent, thereby enhancing the pump efficiency.

[0057] To continuously supply hot clean water to the filtrate delivery system 200, the filtrate delivery system 200 also includes a hot clean water replenishment component 250. The hot clean water replenishment component 250 can be connected to a bleaching-specific hot water tank. The hot clean water replenishment component 250 includes a hot clean water replenishment pipe 251 and a hot clean water replenishment valve 252. The hot clean water replenishment valve 252 is located on the hot clean water replenishment pipe 251. The hot clean water replenishment pipe 251 is detachably connected to the filtrate tank 210. By adjusting the opening degree of the hot clean water replenishment valve 252, the flow rate of the hot clean water replenishment pipe 251 can be controlled, thereby keeping the total delivery volume of the filtrate delivery system 200 stable.

[0058] It should be noted that, in order to achieve automatic control of the above components, the water-saving device 10 of this application also includes a control cabinet. By electrically connecting the light wastewater pump 120, light wastewater conveying control valve 130, light wastewater flow control valve 150, conductivity meter 160, flow meter 170 and hot clean water supply valve 252 to the control cabinet, the automatic control of the above components is achieved, as detailed below:

[0059] The conductivity of the light wastewater is monitored by a conductivity meter 160, and the real-time detection value is transmitted back to the control cabinet. The control cabinet can compare the received data with the preset value. When the value is lower than the preset value, the system operates normally. When the value is higher than the preset value, the control cabinet sends a command to the light wastewater flow control valve 150 and the light wastewater pump 120 to reduce the flow rate of the light wastewater delivery pipe 140, and sends a command to the hot clean water supply valve 252 to increase the flow rate of the hot clean water supply pipe 251. When the data is too high, a command is sent to the light wastewater delivery control valve 130 and the light wastewater pump 120 to shut off the light wastewater delivery control valve 130 and stop the light wastewater pump 120. At the same time, a command is sent to the hot clean water supply valve 252 to further increase the flow rate of the hot clean water supply pipe 251.

[0060] The flow rate of light wastewater is monitored by flow meter 170, and the real-time detection value is sent back to the control cabinet. When the water stored in light wastewater tank 110 is low, the flow rate of light wastewater is less than the preset value. The control cabinet receives the returned data and sends a command to hot clean water supply valve 252 to increase the flow rate of hot clean water supply pipe 251.

[0061] The above-mentioned automatic control method can improve the automation level of the water-saving device 10, ensure that the conductivity of the filtrate meets the requirements for use, save the amount of hot water to replenish, and reduce manpower input.

[0062] To ensure uniform mixing of the filtrate and light wastewater, at least two filtrate delivery branch pipes 241 are typically connected to the main reaction tower 300 at the end of the filtrate delivery pipe 240, and each filtrate delivery branch pipe 241 is equipped with a filtrate delivery branch pipe 241 valve. This design allows the high-speed flowing filtrate, upon entering the main reaction tower 300, to continue flowing a distance due to inertia and further mix with the surrounding filtrate, resulting in more uniform mixing. In particular, in some embodiments, the at least two filtrate delivery branch pipes 241 are connected to the main reaction tower 300 at a certain angle, allowing for more thorough collision and fusion of the filtrate flowing from the at least two filtrate delivery branch pipes 241, resulting in a more uniform mixture.

[0063] By installing a filtrate delivery branch valve 241a on each filtrate delivery branch pipe 241, each filtrate delivery branch pipe 241 can serve as a backup for the others, making water outage maintenance more convenient.

[0064] The structure and principle of the filtrate delivery system 200 have been introduced above.

[0065] Of course, since the temperature of the light wastewater and filtrate is 60-80℃, in order to ensure that the temperature loss of the mixed filtrate is minimal when it reaches the main reaction tower 300, and to prevent personnel from being scalded, insulation sections need to be installed in the light wastewater system 100 and the filtrate conveying system 200. These insulation sections are typically made of rubber-plastic insulation cotton or centrifugal glass wool, and are mainly wrapped and adhered to the light wastewater tank 110, light wastewater conveying pipe 140, light wastewater conveying control valve 130, light wastewater flow control valve 150, filtrate tank 210, filtrate conveying pipe 240, and filtrate conveying control valve 230. In some embodiments, to prevent the insulation sections from weathering and physical damage outdoors, a metal protective shell needs to be attached to the outside of the insulation sections for better protection.

[0066] The structure and principle of the water-saving device 10 have been introduced above. The specific operation process of the water-saving device 10 will be introduced next.

[0067] Before activating the water-saving device 10, some preparatory work is required. First, ensure that the liquid level in the light wastewater tank 110 is greater than or equal to 30%. A low liquid level will cause turbulent water flow into the light wastewater pump 120 and significantly increase the risk of cavitation. In some embodiments, a level gauge is added to the light wastewater tank 110 and linked to the light wastewater pump 120; when the liquid level drops below 10%, the light wastewater pump 120 will automatically stop. Next, ensure the conductivity meter 160 is calibrated correctly, then vent the light wastewater pump 120 completely. Next, check the light wastewater delivery pipe 140 for leaks, paying particular attention to the connections between the light wastewater delivery pipe 140 and various components, as these are the most prone to leaks. Finally, check that the electrical connections between the control cabinet and each component are normal, and that signal communication is normal, facilitating real-time control after operation.

[0068] After the preparatory work is completed, some parameter settings need to be configured through the control cabinet. First, the threshold for the conductivity meter 160 to monitor the conductivity of light wastewater should be less than or equal to 100 μS / cm, and the alarm value should be greater than 150 μS / cm. Next, the target liquid level of the filtrate tank 210 should be set to 40%-60%, with a liquid level fluctuation range of less than or equal to 5%, and the initial light wastewater flow rate should be 30 L / s. The output pressure of the light wastewater pump 120 should also be set to 0.3-0.5 MPa.

[0069] After setting the parameters, the operation of the water-saving device 10 needs to be adjusted in real time. When the light wastewater in the light wastewater tank 110 is sufficient and greater than or equal to 30%, the control cabinet adjusts the opening of the light wastewater flow control valve 150 to control the light wastewater flow rate at 30-40 L / s, and simultaneously adjusts the flow rate of the hot clean water supply pipe 251 to reduce the hot clean water supply by 30-40 L / s, maintaining a stable total supply. When the light wastewater in the light wastewater tank 110 is insufficient and less than 10%, the control cabinet closes the light wastewater delivery control valve 130 and fully opens the hot clean water supply valve 252, switching to the full hot clean water mode. When the conductivity meter 160 detects that the conductivity of light wastewater is >100μS / cm for three consecutive times, the control cabinet automatically reduces the opening of the light wastewater flow control valve 150 (reducing the flow by 10% for every 5μS / cm exceeding the standard) and increases the amount of hot clean water to ensure washing quality; if the conductivity is >150μS / cm, an audible and visual alarm is triggered and the light wastewater delivery control valve 130 is automatically closed, switching to full hot clean water mode.

[0070] In daily operation and maintenance, the light wastewater conveying pipe 140 and the filtrate conveying pipe 240 should be inspected every 2 hours for scale buildup, and cleaned regularly with 5% citric acid. When the light wastewater flow control valve 150 malfunctions, the control cabinet will automatically close the light wastewater conveying control valve 130 and switch to the full hot water mode.

[0071] Through the above operating procedures and maintenance, the consumption of hot water in the EOP section can be reduced by 15%-20%, the whiteness and strength of the slurry can be kept the same as the original process, and the emission of adsorbable organic halogens (AOX) can be reduced by 12%-15%, achieving multiple benefits of water saving, cost reduction and environmental protection.

[0072] In the above context, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.

[0073] In the description of the embodiments of this application, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. "And / or" in this article is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone.

[0074] It should be noted that, for ease of description, only the parts relevant to the application are shown in the accompanying drawings. Unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0075] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed, and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. The scope of this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the above-described application concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. A water-saving device, characterized in that, It includes a light wastewater system (100), a filtrate delivery system (200), and a main reaction tower (300); The light wastewater system (100) is a supplementary system to the filtrate delivery system (200), and the outlet end of the light wastewater system (100) is connected to the filtrate delivery system (200). The filtrate delivery system (200) provides filtrate to the main reaction tower (300), and the outlet end of the filtrate delivery system (200) is connected to the main reaction tower (300).

2. The water-saving device as described in claim 1, characterized in that, The light wastewater system (100) includes a light wastewater tank (110), a light wastewater pump (120), a light wastewater delivery control valve (130), a light wastewater delivery pipe (140), and a light wastewater flow control valve (150); One end of the light wastewater conveying pipe (140) is connected to the light wastewater tank (110), and the other end of the light wastewater conveying pipe (140) is connected to the filtrate conveying system (200); The light wastewater pump (120) and the light wastewater delivery control valve (130) are located on the light wastewater delivery pipe (140) and at one end close to the light wastewater tank (110); The light wastewater flow control valve (150) is located on the light wastewater delivery pipe (140) and at one end close to the filtrate delivery system (200).

3. The water-saving device as described in claim 2, characterized in that, The filtrate delivery system (200) includes a filtrate tank (210), a filtrate pressurization pump (220), a filtrate delivery control valve (230), and a filtrate delivery pipe (240); One end of the filtrate delivery pipe (240) is connected to the filtrate tank (210), and the other end of the filtrate delivery pipe (240) is connected to the main reaction tower (300); The filtrate pressurization pump (220) and the filtrate delivery control valve (230) are located on the filtrate delivery pipe (240) and at one end near the filtrate tank (210).

4. The water-saving device as described in claim 3, characterized in that, The light wastewater conveying pipe (140) is connected to the filtrate conveying pipe (240), and the distance between the connection position and the filtrate tank (210) is 1m-1.5m.

5. The water-saving device as described in claim 3, characterized in that, The light wastewater system (100) also includes a conductivity meter (160), which is installed on the light wastewater conveying pipe (140) and the distance from the connection point between the light wastewater conveying pipe (140) and the filtrate conveying pipe (240) is less than 1m.

6. The water-saving device as described in claim 5, characterized in that, The filtrate delivery system (200) further includes a hot clean water supply component (250), which includes a hot clean water supply pipe (251) and a hot clean water supply valve (252). The hot clean water supply valve (252) is located on the hot clean water supply pipe (251), and the hot clean water supply pipe (251) is connected to the filtrate tank (210).

7. The water-saving device as described in claim 6, characterized in that, It also includes a control cabinet, and the light sewage pump (120), the light sewage delivery control valve (130), the light sewage flow control valve (150), the conductivity meter (160) and the hot clean water supply valve (252) are electrically connected to the control cabinet respectively.

8. The water-saving device as described in claim 3, characterized in that, The filtrate delivery pipe (240) includes at least two filtrate delivery branch pipes (241) connected to the main reaction tower (300), and each of the filtrate delivery branch pipes (241) is equipped with a filtrate delivery branch pipe valve (241a).

9. The water-saving device as described in claim 7, characterized in that, The light wastewater system (100) also includes a flow meter (170), which is located on the light wastewater delivery pipe (140) and between the light wastewater flow control valve (150) and the light wastewater delivery control valve (130); The flow meter (170) is electrically connected to the control cabinet.

10. The water-saving device as described in claim 1, characterized in that, It also includes a heat insulation section located in the light wastewater system (100) and the filtrate delivery system (200) to ensure that the temperature of the light wastewater and filtrate is maintained at a set value.

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