Efficient water-saving and emission-reducing system and method for petroleum refining circulating cooling water

Abstract

The invention relates to the technical field of industrial water treatment, in particular to a petroleum refining circulating cooling water efficient water-saving emission reduction system and method.The system comprises a circulating cooling water side filtering unit used for receiving a part of high-temperature circulating cooling water prone to scaling after heat absorption and filtering out suspended matter in water; the circulating cooling water bypass efficient crystallization, hardness removal and softening unit is used for receiving the other part of high-temperature circulating cooling water which absorbs heat and is prone to scaling, if the water hardness exceeds a preset value, rapid crystallization, hardness removal and softening treatment is conducted on the circulating cooling water, then deep filtration and hardness removal are conducted, and if the water hardness does not exceed the preset value, the circulating cooling water bypass efficient crystallization, hardness removal and softening unit is started. And if not, the other path of circulating cooling water is directly subjected to deep filtration and hardness removal. According to the scheme, the scaling ion concentration in the circulating cooling water is reduced, the suspended matter concentration and turbidity in the circulating cooling water are reduced, and efficient water saving and emission reduction are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of industrial water treatment, and in particular to a high-efficiency water-saving and emission-reducing system and method for circulating cooling water in petroleum refining. Background Art

[0002] The petroleum refining industry is a major water consumer. The water consumption of a single product is an important indicator for assessing the production efficiency of refining enterprises. At the same time, water conservation and emission reduction are also important responsibilities faced by petrochemical enterprises. Especially under the requirement of gradually eliminating inefficient, unstable and substandard water-related systems, combined with the current situation of production enterprises, increase R&D investment, gradually adopt new technologies and processes, improve wastewater utilization, gradually reduce the amount of sewage discharged, and gradually approach the goal of zero discharge of industrial wastewater.

[0003] At present, the water-saving technology research carried out by petroleum refining and chemical industry enterprises in the field of industrial circulating cooling water saving mainly focuses on increasing the number of circulating cooling water cycles, increasing the concentration multiples, reducing the amount of sewage, reducing the amount of fresh water replenishment, and increasing the reuse rate of wastewater deep treatment. In this process, the link that has the greatest impact on water saving and emission reduction is how to increase the concentration multiples of circulating cooling water and increase the number of cooling water cycles. However, rashly increasing the concentration multiples of circulating cooling water will inevitably face the enrichment and precipitation of scaling substances in the circulating cooling water, causing large-scale scaling of the heat exchange system, affecting the heat exchange effect, and then threatening the safe and stable operation of the refining production equipment. Therefore, how to efficiently and cleanly separate the scaling substances in the circulating cooling water or form a stable working condition to prevent scaling of the heat exchange unit under high concentration multiples is a water-saving problem currently faced by most petroleum refining and chemical production enterprises.

[0004] At present, there are several main processes for solving the enrichment and precipitation of scaling substances in circulating cooling water: traditional lime hardness removal and softening treatment process, ion exchange softening treatment process, high-efficiency chemical scale inhibition and stabilization process, etc. Among them, the traditional lime softening + flocculation precipitation process has the problems of too long reaction process, cumbersome units, large floor space, high cost, large lime dosage, high system failure rate, and the generated sludge is solid waste, which is difficult to properly dispose of. At the same time, the technology has limited water hardness reduction, and cannot effectively remove scaling substances in the water. It has limited effect on increasing the concentration multiple of circulating cooling water, resulting in high hardness and alkalinity of circulating cooling water, large amount of sewage discharge, and still a large scaling risk. The comprehensive water-saving and emission reduction effect is not obvious; the ion exchange softening treatment process has the problems of low treatment load, small cycle water output, frequent regeneration, and the generated regenerated acidic wastewater cannot be recycled and treated, which brings new high-salt sewage and corrosion problems. It is also gradually being eliminated; high-efficiency scale inhibition agent treatment is the process route still adopted by most companies at present. However, this process adds a large amount of chemical agents to the cooling water system on a daily basis, but can only control a limited concentration multiple. The system has a large amount of sewage discharge and a large amount of fresh water replenishment. The residual chemicals in the sewage have a lot of negative effects on water pollution and deep reuse. The cost of sewage treatment is high, and resource reuse cannot be achieved. The utilization rate of industrial water is low, the water consumption of each product in the enterprise is high, and the water resource consumption is large. At the same time, the addition of a large amount of chemical substances increases the environmental burden, and the cost of agents is also high. The overall water saving and emission reduction effect is not obvious. In order to completely eliminate the drawbacks of the existing technology, it is necessary to design targeted technical solutions to solve them. Summary of the invention

[0005] The purpose of the present invention is to overcome the problems existing in the prior art and provide a system and method for efficiently saving water and reducing emissions of circulating cooling water in petroleum refining.

[0006] In order to achieve the above-mentioned object, the first aspect of the present invention provides a high-efficiency water-saving and emission-reducing system for circulating cooling water in a petroleum refinery, characterized in that it comprises:

[0007] The circulating cooling water bypass filter unit is used to receive a portion of the high-temperature and scaling-prone circulating cooling water after absorbing heat, and filter and remove suspended matter in the water;

[0008] The circulating cooling water bypass high-efficiency crystallization and softening unit is used to receive another part of the high-temperature and easy-to-scale circulating cooling water after absorbing heat. If the water hardness exceeds the preset value, the circulating cooling water is subjected to rapid crystallization and softening treatment, and then deep filtration and hardness removal. If the water hardness does not exceed the preset value, the other circulating cooling water is directly subjected to deep filtration and hardness removal;

[0009] A circulating water return residual pressure bypass water supply unit is used, which is respectively connected to the circulating cooling water bypass filter unit and the circulating cooling water bypass high-efficiency crystallization hardness removal and softening unit pipeline, and is used to use the circulating cooling water return residual pressure as a source of power to send the high-temperature and easy-to-scale circulating cooling water into the circulating cooling water bypass filter unit and the circulating cooling water bypass high-efficiency crystallization hardness removal and softening unit respectively;

[0010] The big data intelligent management and control unit is electrically connected to the circulating cooling water bypass filtration unit and the circulating cooling water bypass high-efficiency crystallization hardness removal and softening unit, respectively, and is used to monitor and judge the water quality indicators in the system in real time, feed back the water hardness to the circulating cooling water bypass high-efficiency crystallization hardness removal and softening unit, and control the water inlet and outlet processes of the circulating cooling water bypass filtration unit and the circulating cooling water bypass high-efficiency crystallization hardness removal and softening unit.

[0011] The second aspect of the present invention provides a method for efficiently saving water and reducing emissions of circulating cooling water in petroleum refining, comprising the following method:

[0012] The high-temperature and easy-to-scale circulating cooling water after heat absorption is divided into two paths, one of which is filtered to remove suspended solids in the water; the other is used to determine the water hardness. If the water hardness exceeds the preset value, the other circulating cooling water is subjected to rapid crystallization to remove hardness and softening treatment, and then deep filtration to remove hardness. If the water hardness does not exceed the preset value, the other circulating cooling water is directly subjected to deep filtration to remove hardness.

[0013] The circulating cooling water treated in the two ways is reused for circulating cooling.

[0014] The technical solution of the present invention has the following beneficial effects: 1. The process device designed by the present invention has a simple process, modular design, high processing efficiency, high degree of automation, small footprint, small amount of civil engineering, and strong replicability of the complete process package, which can reduce the overall sewage discharge and production water consumption of the refining enterprise, realize water saving and efficiency improvement in the entire refining industry, and has broad application prospects; 2. The process device designed by the present invention belongs to the "recycling method" process route, which can completely replace the traditional "discarding method" process route, and ultimately achieve water saving and emission reduction, energy saving and consumption reduction, and help petroleum refining enterprises to implement the "green enterprise" goal and social responsibility; 3. The complete set of water-saving and emission-reduction devices designed by the present invention is a combination of self-induced chemical crystallization reaction and pellet physical fluidization reaction, with high flow rate, high decalcification rate, good dehardening effect, low effluent hardness, low effluent turbidity, and strong operation stability. The turbidity of the effluent is small, the effluent quality is high, and the effluent hardness can be automatically adjusted at any time by the big data intelligent management and control system according to the operating conditions of the main engine of the refining and chemical production, which effectively guarantees the safe, efficient and economical operation of the refining and chemical production system, and can greatly increase the concentration multiple of the circulating cooling water system, realize water saving and emission reduction, and improve the utilization rate of industrial wastewater in enterprises. At the same time, it can reduce the amount of water entering the subsequent high-salt water deep treatment system, and greatly reduce the operating cost of high-salt water deep treatment and reuse; 4. The process device designed by the present invention has simple by-products, and the only by-product is 2-3mm calcium carbonate particles. The purity of calcium carbonate is high, exceeding 92%, and it is basically free of water, which can be completely reused in the desulfurization section of the enterprise boiler; the by-product resource reuse is realized, and the circular economy is realized. The "recycling method" process route of the present invention is far superior to the traditional "discarding method" process route. And there is no other wastewater and waste discharge, which completely solves the disadvantages of traditional processes, has higher operating efficiency, lower operating costs, and is more environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of a highly efficient water-saving and emission-reducing device for a circulating cooling water system in a petroleum refinery.

[0016] Figure 1 In the middle: mechanical ventilation cooling tower-1, circulating cooling water fore pool-2, circulating cooling water pump-3, refining heat exchange unit-4, mechanical ventilation fan-5, circulating cooling water side filtration unit-6, crystallization hardness removal and softening equipment-7, hardness removal post-side filtration equipment-8, sewage pool-9, high salt water treatment unit-10, thermal power boiler desulfurization section-11, dosing room-12. DETAILED DESCRIPTION

[0017] The specific implementation of the embodiment of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the embodiment of the present invention, and is not used to limit the embodiment of the present invention.

[0018] A first aspect of an embodiment of the present invention provides a system for efficiently saving water and reducing emissions of circulating cooling water for petroleum refining, comprising:

[0019] The circulating cooling water bypass filter unit is used to receive a portion of the high-temperature and scaling-prone circulating cooling water after absorbing heat, and filter and remove suspended matter in the water;

[0020] The circulating cooling water bypass high-efficiency crystallization and softening unit is used to receive another part of the high-temperature and easy-to-scale circulating cooling water after absorbing heat. If the water hardness exceeds the preset value, the circulating cooling water is subjected to rapid crystallization and softening treatment, and then deep filtration and hardness removal. If the water hardness does not exceed the preset value, the other circulating cooling water is directly subjected to deep filtration and hardness removal;

[0021] A circulating water return residual pressure bypass water supply unit is used, which is connected to the circulating cooling water bypass filter unit and the circulating cooling water bypass high-efficiency crystallization hardness removal and softening unit pipeline respectively, and is used to use the circulating cooling water return residual pressure as a source of power to send the high-temperature and easy-to-scale circulating cooling water into the circulating cooling water bypass filter unit and the circulating cooling water bypass high-efficiency crystallization hardness removal and softening unit respectively; the circulating water return residual pressure bypass water supply unit includes a bypass water receiving pipeline installed in the circulating cooling water return pipeline and a detection instrument and a control valve arranged on the bypass water receiving pipeline;

[0022] The big data intelligent management and control unit is electrically connected to the circulating cooling water bypass filtration unit and the circulating cooling water bypass high-efficiency crystallization hardness removal and softening unit, respectively, and is used to monitor and judge the water quality indicators in the system in real time, feed back the water hardness to the circulating cooling water bypass high-efficiency crystallization hardness removal and softening unit, and control the water inlet and outlet processes of the circulating cooling water bypass filtration unit and the circulating cooling water bypass high-efficiency crystallization hardness removal and softening unit.

[0023] The circulating cooling water bypass filtration unit comprises a crystallization hardness removal and softening device and a post-hardness removal bypass filtration device, and the crystallization hardness removal and softening device and the post-hardness removal bypass filtration device are connected by pipelines.

[0024] The crystallization hardness removal and softening equipment is used to perform rapid crystallization hardness removal and softening treatment on circulating cooling water. The treated circulating cooling water flows into the post-hardness removal bypass filtration equipment through a pipeline. The post-hardness removal bypass filtration equipment is used for deep filtration and hardness removal.

[0025] The circulating cooling water return residual pressure bypass water supply unit is to install bypass water pipes, detection instruments and control valves on the circulating cooling water return pipe, and use the circulating cooling water return residual pressure as the source of power for the hardness removal and softening unit and the filtration unit, replacing the traditional design of water supply pipe network and water supply pump, so as to achieve low-cost operation of the system and simplify control. The above units and modules constitute a set of water-saving and emission reduction equipment for petroleum refining circulating cooling water, which removes different scaling substances and turbidity through step-by-step reaction and state control, realizes the softening and turbidity reduction of circulating cooling water, and realizes the resource reuse of by-products.

[0026] Furthermore, the circulating cooling water bypass filtration unit also includes a circulating cooling water bypass water inlet module, a crystal nucleus optimization adding module, an automatic dosing control module, a self-induced crystallization granulation de-hardening and softening module, a monitoring and automatic control module, a particle emission collection and by-product comprehensive utilization module, an automatic water inlet module, and an unpowered self-filtration and self-backwashing module.

[0027] The automatic water inlet module is used to send the high-temperature and easily scaled circulating cooling water after absorbing heat into the circulating cooling water bypass filter unit;

[0028] The unpowered self-filtration and self-backwashing module is used to perform deep filtration and turbidity reduction on the effluent after high-efficiency hardness removal and softening, reduce the content of suspended solids, and realize its automatic backwashing regeneration and recovery filtration function. It is located at the rear of the high-efficiency hardness removal reactor and is connected in series with the high-efficiency hardness removal reactor through the outlet pipeline.

[0029] The circulating cooling water bypass water inlet module is used to send the high-temperature and easy-to-scale circulating cooling water after heat absorption into the crystallization hardness removal and softening equipment or the post-hardness removal bypass filtration equipment;

[0030] The crystal nucleus preferred adding module is used to uniformly and stably add the selected special induced crystal nuclei to the crystal separation area of ​​the high-efficiency hardness removal reactor, and is located on the side of the high-efficiency hardness removal reactor. It includes a high-efficiency hardness removal reactor and a crystal nucleus feeder. The high-efficiency hardness removal reactor directly draws water to the crystal nucleus feeder through the top water outlet pipe. The top water outlet pipe is equipped with an online electromagnetic flowmeter and an electric regulating valve to monitor and adjust the fluidized water volume of the crystal nucleus feeder in real time;

[0031] The automatic dosing control module is used to uniformly and continuously add the liquid alkali or soda ash required for the induced crystallization reaction to the crystallization reaction zone of the high-efficiency hardness removal reactor, and can automatically control the dosage according to the inlet and outlet water indicators collected by the detection and automatic control module to achieve accurate dosage of the agent. It is located at the auxiliary machine position of the high-efficiency hardness removal reactor, and the dosing point is located at the main reaction zone position above the water distribution area of ​​the high-efficiency hardness removal reactor; the self-induced crystallization granulation hardness removal and softening module is used for crystallization granulation hardness removal, and is located in the hardness removal and softening workshop or the center of the skid-mounted integrated platform;

[0032] The monitoring and automatic control module is used to monitor the water quality of the inlet and outlet water of the system online, and after the big data intelligent management and control unit performs logical analysis on the collected data, the automatic control module issues instructions to other modules to realize automatic regulation of the inlet flow rate and the amount of added medicine, and realize automatic regulation and operation of the system. It is installed on the inlet and outlet water pipelines of the de-hardening and softening device and in the on-site control cabinet;

[0033] The particle emission collection and by-product comprehensive utilization module is connected to the crystallization de-hardening and softening equipment, and is used to recycle the by-product calcium carbonate particles, including an automatic particle emission pipeline, a self-flushing pipeline and a self-separation and collection box, which is used to realize automatic transportation and resource reuse of by-products.

[0034] The self-induced crystallization granulation hardness removal and softening module utilizes the optimized crystallization inducing material, which has strong physical and chemical stability, and its own hardness and density are suitable for the conditions required for the chemical reaction and physical reaction of crystallization granulation hardness removal; the module reacts in steps, internal circulation fluidization, and can realize controllable and adjustable operation mode. The preferred addition of crystal nuclei is to directly lead water to the crystal nucleus dosing system from the outlet pipe at the top of the existing high-efficiency hardness removal reactor. The online electromagnetic flowmeter and electric regulating valve designed on the water diversion pipe can monitor and adjust the fluidized water volume of the crystal nucleus dosing system in real time. Big data intelligent management and control is an automatic intelligent monitoring platform. The whole set of equipment will automatically collect relevant parameters during operation to realize intelligent process monitoring, ensure stable operation of the system, and ensure that the process indicators meet the requirements.

[0035] Furthermore, the big data intelligent management and control unit is used to automatically and continuously monitor the inlet and outlet water quality indicators of the hardness removal and softening equipment, link the automatic dosing control module to add drugs, and control the water quality of the produced water to meet the standards in real time; and is used to automatically and continuously monitor the outlet water quality of the circulating cooling water bypass filter unit to ensure the stability of the recycled water quality.

[0036] Furthermore, the system also includes a cooling tower, a circulating cooling water forebay and a heat exchange unit.

[0037] The cooling tower is used to perform the heat dissipation, temperature reduction and collection functions of circulating cooling water;

[0038] The heat dissipation and cooling collection of the circulating cooling water is respectively connected to the cooling tower and the heat exchange unit pipeline, and is used to collect the circulating cooling water after the heat dissipation of the cooling tower, and perform descaling and sterilization treatment, and then send the circulating cooling water to the heat exchange unit;

[0039] The heat exchange unit is connected to the circulating cooling water bypass filtration unit and the circulating cooling water bypass high-efficiency crystallization and de-hardening and softening unit pipelines respectively, and is used to transport the high-temperature and easily scaled circulating cooling water after absorbing heat.

[0040] The process flow of the high-efficiency water-saving and emission-reduction system for circulating cooling water in petroleum refining is as follows: Figure 1As shown, the mechanical ventilation cooling tower 1 of the petroleum refining and chemical industry enterprise undertakes the functions of heat dissipation, cooling and collection of circulating cooling water in daily normal operation. After ventilation and heat dissipation, the circulating cooling water is first collected in the circulating cooling water forepool 2, and a certain amount of slow-release antiscalant and bactericide is added through the dosing room 12. After mixing, the circulating cooling water is pumped out by the circulating cooling water pump 3 and pumped into the heat exchange unit 4 of the petroleum refining production system to perform heat exchange and cooling on the refining production equipment and production product media. The circulating cooling water has a higher temperature after absorbing heat, and returns to the mechanical ventilation cooling tower 1 through the residual pressure of the pipeline network. After forced ventilation, heat exchange and cooling by the mechanical ventilation fan 5, it converges to the bottom of the mechanical ventilation cooling tower 1 again, and the cycle is repeated. In order to achieve the goal of efficiently removing scaling substances and suspended solids from circulating cooling water, the high-temperature and scaling-prone circulating cooling water discharged from the refining heat exchange unit 4 is introduced into the circulating cooling water bypass filter unit 6 through the return water bypass pipeline to filter the suspended solids and other impurities in the circulating cooling water. At the same time, part of the return water is diverted into the high-efficiency crystallization hardness removal and softening equipment 7 through the return water residual pressure diversion device. Under the dual effects of chemical crystallization and physical fluidization, the scaling substances in the bypass circulating cooling water are quickly and efficiently physically separated, and the total hardness and alkalinity of the effluent water are greatly reduced. The softened effluent is again used to enter the special hardness removal post-bypass filter equipment 8 for deep filtration and turbidity reduction treatment using the residual pressure. Finally, the high-quality water supply with low hardness, low alkali and low turbidity is replenished into the circulating cooling water front pool 2, mixed with the cooling tower water, and then pumped out by the circulating cooling water pump 3 and pumped into the refining heat exchange unit 4 again. In the heat unit 4, heat exchange and cooling are involved. The quality of the effluent after bypass hardness removal and softening and high-efficiency filtration is high, the concentration of scaling substances is greatly reduced, the circulating cooling water quality entering the refining heat exchange unit is high, the scaling rate and risk of the heat exchange unit are greatly reduced, the sewage discharge of the circulating cooling water system is greatly reduced, the system concentration multiple is gradually increased, and the amount of fresh water replenishment is significantly reduced, achieving the effect of water saving and emission reduction; at the same time, due to the good water quality of the system, the amount of high-salt wastewater discharged from the circulating cooling system entering the sewage pool 9 is significantly reduced, and then the amount of high-salt wastewater entering the subsequent high-salt wastewater deep treatment unit 10 is significantly reduced, the load of the high-salt water deep treatment unit 10 is reduced, and the overall operating cost is greatly reduced. At the same time, the calcium carbonate particles, a by-product of the process device, are directly transported to the desulfurization section 11 of the thermal power boiler for comprehensive utilization of by-products, realizing a circular economy.

[0041] By physically extracting and separating scaling substances in circulating cooling water, reducing scaling ion concentration in circulating cooling water, reducing suspended solids concentration and turbidity in circulating cooling water, we can thoroughly solve the problems of low concentration multiple of circulating cooling water system in petroleum refining, large system sewage volume, large amount of chemical agent addition, difficulty in treating circulating cooling water sewage, high turbidity of effluent after softening, difficulty in reuse, high operating cost of deep treatment of sewage, inability to realize resource reuse, low industrial water utilization rate, high water resource consumption, etc., to achieve efficient water saving and emission reduction.

[0042] Based on the same inventive concept, the second aspect of the present invention proposes a method for efficiently saving water and reducing emissions of circulating cooling water in petroleum refining, including the following method:

[0043] The high-temperature and easy-to-scale circulating cooling water after heat absorption is divided into two paths, one of which is filtered to remove suspended solids in the water; the other is used to determine the water hardness. If the water hardness exceeds the preset value, the other circulating cooling water is subjected to rapid crystallization to remove hardness and softening treatment, and then deep filtration to remove hardness. If the water hardness does not exceed the preset value, the other circulating cooling water is directly subjected to deep filtration to remove hardness.

[0044] Reusing the circulating cooling water after the two-way treatment to participate in circulating cooling;

[0045] The carbonate byproduct obtained by subjecting the other circulating cooling water to rapid crystallization, de-hardening and softening treatment is recycled.

[0046] In summary, the technical solution of the present invention has the following effects: 1. The process device designed by the present invention has a simple process, modular design, high processing efficiency, high degree of automation, small footprint, small amount of civil engineering, and strong replicability of the complete process package. It can reduce the overall sewage discharge and production water consumption of refining enterprises, achieve water saving and efficiency improvement in the entire refining industry, and have broad application prospects; 2. The process device designed by the present invention belongs to the "recycling method" process route, which can completely replace the traditional process route of the "discarding method", and ultimately achieve water saving and emission reduction, energy saving and consumption reduction, and help petroleum refining enterprises to implement the "green enterprise" goal and social responsibility; 3. The complete set of water-saving and emission reduction devices designed by the present invention is a combination of self-induced chemical crystallization reaction and pellet physical fluidization reaction, with high flow rate, high decalcification rate, good dehardening effect, low effluent hardness, low effluent turbidity, and strong operation stability , the turbidity of the effluent fluctuates little, the effluent quality is high, and the effluent hardness can be automatically adjusted by the big data intelligent management and control system at any time according to the operating conditions of the main engine of the refining and chemical production, which effectively guarantees the safe, efficient and economical operation of the refining and chemical production system, and at the same time can greatly increase the concentration multiple of the circulating cooling water system, realize water saving and emission reduction, improve the utilization rate of industrial wastewater in enterprises, and at the same time can reduce the amount of water entering the subsequent high-salt water deep treatment system, and greatly reduce the operating cost of high-salt water deep treatment and reuse; 4. The process device designed by the present invention has simple by-products, and the only by-product is 2-3mm calcium carbonate particles, which have high purity, more than 92%, and basically do not contain water, and can be completely reused in the desulfurization section of the enterprise boiler; realize the resource reuse of by-products and realize the circular economy. The "recycling method" process route of the present invention is far superior to the traditional "discarding method" process route. And there is no other wastewater and waste discharge, which completely solves the disadvantages of traditional processes, has higher operating efficiency, lower operating costs, and is more environmentally friendly.

[0047] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various specific technical features in any suitable manner. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations. However, these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A highly efficient water-saving and emission-reducing system for circulating cooling water in petroleum refining, characterized in that: include: The circulating cooling water bypass filter unit is used to receive a portion of the high-temperature and scaling-prone circulating cooling water after absorbing heat, and filter and remove suspended matter in the water; The circulating cooling water bypass high-efficiency crystallization and softening unit is used to receive another part of the high-temperature and easy-to-scale circulating cooling water after absorbing heat. If the water hardness exceeds the preset value, the circulating cooling water is subjected to rapid crystallization and softening treatment, and then deep filtration and hardness removal. If the water hardness does not exceed the preset value, the other circulating cooling water is directly subjected to deep filtration and hardness removal; A circulating water return residual pressure bypass water supply unit is used, which is respectively connected to the circulating cooling water bypass filter unit and the circulating cooling water bypass high-efficiency crystallization hardness removal and softening unit pipeline, and is used to use the circulating cooling water return residual pressure as a source of power to send the high-temperature and easy-to-scale circulating cooling water into the circulating cooling water bypass filter unit and the circulating cooling water bypass high-efficiency crystallization hardness removal and softening unit respectively; The big data intelligent management and control unit is electrically connected to the circulating cooling water bypass filtration unit and the circulating cooling water bypass high-efficiency crystallization hardness removal and softening unit, respectively, and is used to monitor and judge the water quality indicators in the system in real time, feed back the water hardness to the circulating cooling water bypass high-efficiency crystallization hardness removal and softening unit, and control the water inlet and outlet processes of the circulating cooling water bypass filtration unit and the circulating cooling water bypass high-efficiency crystallization hardness removal and softening unit.

2. The system according to claim 1, characterized in that The circulating cooling water bypass filtration unit comprises a crystallization hardness removal and softening device and a post-hardness removal bypass filtration device, and the crystallization hardness removal and softening device and the post-hardness removal bypass filtration device are connected by pipelines. The crystallization and hardness removal and softening equipment is used to perform rapid crystallization and hardness removal and softening treatment on circulating cooling water. The treated circulating cooling water flows into the post-hardness removal by-pass filtration equipment through a pipeline. The post-hardness removal by-pass filtration equipment is used to perform deep filtration to reduce turbidity and remove hardness.

3. The system according to claim 2, characterized in that The circulating cooling water bypass filtration unit also includes a circulating cooling water bypass water inlet module, a crystal nucleus optimization adding module, an automatic dosing control module, a self-induced crystallization granulation hardness and softening module, a monitoring and automatic control module, a particle emission collection and by-product comprehensive utilization module, The circulating cooling water bypass water inlet module is used to send the high-temperature and easy-to-scale circulating cooling water after heat absorption into the crystallization hardness removal and softening equipment or the post-hardness removal bypass filtration equipment; The crystal nucleus preferred adding module is used to uniformly and stably add the screened induced crystal nuclei to the crystal separation zone of the high-efficiency hardness removal reactor, and is arranged on the side of the main body of the high-efficiency hardness removal reactor; the crystal nucleus preferred adding module includes the high-efficiency hardness removal reactor and a crystal nucleus feeder, the high-efficiency hardness removal reactor directly draws water to the crystal nucleus feeder through the top water outlet pipe, and the top water outlet pipe is provided with an online electromagnetic flowmeter and an electric regulating valve to monitor and adjust the fluidized water volume of the crystal nucleus feeder in real time; The automatic dosing control module is used to uniformly and continuously add the liquid alkali or soda ash required for inducing the crystallization reaction to the crystallization reaction zone of the high-efficiency hardness removal reactor, and can automatically control the dosage according to the inlet and outlet water indicators collected by the detection and automatic control module to achieve accurate dosing of the reagent; the automatic dosing control module is arranged at the auxiliary machine position of the high-efficiency hardness removal reactor, and the dosing point is arranged at the main reaction zone position above the water distribution area of ​​the high-efficiency hardness removal reactor; The self-induced crystallization granulation hardening and softening module is used for crystallization granulation hardening and is located in the hardening and softening workshop or the center of the skid-mounted integrated platform; The monitoring and automatic control module is used to monitor the water quality of the inlet and outlet water of the system online, and after the collected data is logically analyzed by the big data intelligent management and control unit, the automatic control module issues instructions to other modules to realize automatic regulation of the inlet flow rate and the amount of added medicine, and realize automatic regulation and operation of the system; the monitoring and automatic control module is arranged on the inlet and outlet water pipelines of the de-hardening and softening device and in the on-site control cabinet; The particle emission collection and by-product comprehensive utilization module is connected to the crystallization de-hardening and softening equipment and is used to recycle the by-product calcium carbonate particles.

4. The system according to claim 1, characterized in that The circulating cooling water bypass filter unit includes an automatic water inlet module, an unpowered self-filtration and self-backwashing module. The automatic water inlet module is used to send the high-temperature and scaling-prone circulating cooling water after heat absorption into the circulating cooling water bypass filter unit; The unpowered self-filtration and self-backwashing module is used for deep filtration and turbidity reduction of the effluent after high-efficiency hardness removal and softening, reducing the content of suspended matter, and realizing its automatic backwashing regeneration and restoration of filtration function; the unpowered self-filtration and self-backwashing module is arranged at the rear part of the high-efficiency hardness removal reactor, and is connected in series with the high-efficiency hardness removal reactor through the outlet pipeline.

5. The system according to claim 1, characterized in that The circulating water return residual pressure bypass water supply unit comprises a bypass water receiving pipeline installed in the circulating cooling water return pipeline and a detection instrument and a regulating valve arranged on the bypass water receiving pipeline.

6. The system according to claim 3, characterized in that The particle emission collection and by-product comprehensive utilization module includes an automatic particle emission pipeline, a self-flushing pipeline and a self-separation and collection box, which is used to realize automatic transportation and resource recycling of by-products.

7. The system according to claim 3, characterized in that The big data intelligent management and control unit is used to automatically and continuously monitor the inlet and outlet water quality indicators of the hardness removal and softening equipment, link the automatic dosing control module to add drugs, and control the water quality of the produced water to meet the standards in real time; and is used to automatically and continuously monitor the outlet water quality of the circulating cooling water bypass filter unit to ensure the stability of the recycled water quality.

8. The system according to any one of claims 1 to 7, characterized in that: The system also includes a cooling tower, a circulating cooling water forebay and a heat exchange unit. The cooling tower is used to perform the heat dissipation, temperature reduction and collection functions of circulating cooling water; The circulating cooling water fore pool is connected to the cooling tower and the heat exchange unit pipeline respectively, and is used to collect the circulating cooling water after the heat is dissipated by the cooling tower, and to perform descaling and sterilization treatment, and then send the circulating cooling water to the heat exchange unit; The heat exchange unit is connected to the circulating cooling water bypass filtration unit and the circulating cooling water bypass high-efficiency crystallization and de-hardening and softening unit pipelines respectively, and is used to transport the high-temperature and easily scaled circulating cooling water after absorbing heat.

9. A highly efficient water-saving and emission-reducing method for circulating cooling water in petroleum refining, characterized in that: The following methods are included: The high-temperature and easy-to-scale circulating cooling water after heat absorption is divided into two paths, one of which is filtered to remove suspended solids in the water; the other is used to determine the water hardness. If the water hardness exceeds the preset value, the other circulating cooling water is subjected to rapid crystallization to remove hardness and softening treatment, and then deep filtration to remove hardness. If the water hardness does not exceed the preset value, the other circulating cooling water is directly subjected to deep filtration to remove hardness. The circulating cooling water treated in the two ways is reused for circulating cooling.

10. The method for efficiently saving water and reducing emissions of circulating cooling water in petroleum refining according to claim 9, characterized in that: The carbonate byproduct obtained by subjecting the other circulating cooling water to rapid crystallization, de-hardening and softening treatment is recycled.

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