Treatment system and treatment method for steam condensation water

Abstract

The invention provides a steam condensation water treatment system and method, and relates to the technical field of water treatment. The steam condensation water treatment system comprises a water recycling device, a steam condensation water treatment device and a steam condensation water treatment device, the water quality monitoring system is used for monitoring water quality parameters of the steam condensation water; the water quality purification system at least comprises a primary purification system and a secondary purification system, the primary purification system at least comprises a sand filtration device and a carbon filtration device, the secondary purification system at least comprises a sand filtration device, a carbon filtration device, an ultrafiltration device and a reverse osmosis device, and the water quality purification system is used for purifying the steam condensation water. The first-stage purification system and the second-stage purification system are both selectively communicated with the water recycling device; and the water collecting device is used for storing the steam condensation water purified by the water quality purification system. According to the scheme, water can be selectively and comprehensively purified, the water treatment cost is reduced, and the cyclic utilization rate of water resources is increased.

Description

Technical Field

[0001] The present invention relates to the technical field of water treatment, and in particular to a treatment system and a treatment method for steam condensate. Background Art

[0002] Steam condensate refers to the water that is condensed after the steam is cooled after doing work. Due to the leakage and pollution problems of the heating and exhaust steam recycling devices, the impurities and organic matter in the steam condensate show low quantity and high complexity. The temperature of the recovered steam condensate is high. When it is contaminated by chloride ions (when the temperature is greater than 40°C and the water system contains chlorine, it will cause serious corrosion to carbon steel), its direct reuse to the boiler will cause great trouble to its operation. In the prior art, chlorine-containing steam condensate is reused in the boiler to improve the use of thermal energy, reduce water costs and strengthen the internal water circulation of the enterprise. After long-term operation, the water-cooling screen pipeline is damaged, and the internal scaling and corrosion of the internal pipeline of the boiler are aggravated, resulting in frequent pipe bursts and shutdowns.

[0003] In summary, the steam condensate is directly discharged, and its various indicators are far lower than the discharge indicators. The average water temperature is 50-100℃. Direct discharge as sewage will cause waste of water resources and heat energy. Direct reuse as boiler make-up water will affect boiler operation due to the presence of impurities and organic matter.

[0004] In the prior art, patent CN 220999317 U achieves the purpose of recycling by using activated carbon to purify and recycle steam condensate, but does not consider that the recycled water is seriously polluted, and exceeding the activated carbon adsorption capacity will cause abnormal conditions in the system operation; patent CN 113185024 B can effectively achieve adsorption and interception of iron ion complexes by adding an activator to the steam condensate to be treated and then filtering it, and has a good removal effect on organic matter and suspended matter during the complexation process. However, it does not describe the impact of the filtration effect when the relevant ions are lacking in the condensate system and the organic matter increases.

[0005] Currently, no effective solution has been proposed for the above-mentioned technical problems. Summary of the invention

[0006] The main purpose of the present invention is to provide a steam condensate treatment system and a treatment method to solve the problem of poor steam condensate recovery and utilization treatment effect in the prior art.

[0007] In order to achieve the above-mentioned purpose, according to one aspect of the present invention, a steam condensate treatment system is provided, the treatment system comprising: a water recovery device, the water recovery device is used to collect steam condensate; a water quality monitoring system, the water quality monitoring system is used to monitor the water quality parameters of the steam condensate; a water quality purification system, the water quality purification system comprises at least a primary purification system and a secondary purification system, the primary purification system comprises at least a sand filter device and a carbon filter device, the secondary purification system comprises at least a sand filter device, a carbon filter device, an ultrafiltration device and a reverse osmosis device, the water quality purification system is used to purify the steam condensate, and the primary purification system and the secondary purification system are both selectively connected to the water recovery device; a water collection device, the water collection device is used to store the steam condensate purified by the water quality purification system.

[0008] Furthermore, the water collection device includes a first water production tank and a second water production tank, the first water production tank is used to store steam condensate purified by the primary purification system, and the second water production tank is used to store steam condensate purified by the second water production tank.

[0009] Furthermore, the treatment system also includes: a mixing device, the water outlet end of the mixing device is connected to the secondary purification system, the mixing device has a first water inlet end and a second water inlet end, and the first water inlet end is selectively connected to the water recovery device; wherein the second water inlet end is used to introduce mixing water, and the mixing water is used to be mixed with the steam condensate water entering the mixing device.

[0010] Furthermore, the processing system also includes: a heat exchanger, which is used to exchange heat and cool the steam condensate.

[0011] According to another aspect of the present invention, a method for treating steam condensate is provided. The method is based on the above-mentioned steam condensate treatment system, and the method includes: monitoring water quality parameters of the steam condensate in a water recovery device, the water quality parameters including at least one of the following: TOC, TDS, turbidity, ammonia nitrogen, total nitrogen, and free chlorine; when it is determined that the water quality parameters meet the preset purification conditions, purifying the steam condensate through a water purification system, and storing the purified steam condensate in a water collection device.

[0012] Furthermore, the water quality parameters include at least TOC and TDS, and the method also includes the following steps: when it is determined that the water quality parameters meet the preset discharge conditions, the steam condensate is discharged into the sewage pool; wherein the preset discharge conditions are TDS>1000ppm, and / or TOC>150ppm.

[0013] Furthermore, the water quality parameters include at least TOC and TDS. When it is determined that the water quality parameters meet the preset purification conditions, the steam condensate is purified by the water purification system, and the purified steam condensate is stored in the water collection device, including the following steps: when it is determined that the water quality parameters meet the first purification condition in the preset purification conditions, the steam condensate is purified by the primary purification system, and the purified steam condensate is stored in the first water production tank; wherein the first purification condition is TDS≤50ppm and TOC≤10ppm.

[0014] Furthermore, when it is determined that the water quality parameters meet the preset purification conditions, the steam condensate is purified by a water purification system, and the purified steam condensate is stored in a water collection device, and the following steps are also included: when it is determined that the water quality parameters meet the second purification condition in the preset purification conditions, the steam condensate is purified by a secondary purification system, and the purified steam condensate is stored in a second water production tank; wherein the second purification condition is 50≤TDS≤1000ppm, and / or, 10ppm≤TOC≤150ppm.

[0015] Furthermore, before purifying the steam condensate through the secondary purification system, the method also includes the following steps: blending the steam condensate through a blending device so that the steam condensate meets the third purification condition; wherein the third purification condition is TDS≤340ppm and TOC≤150ppm.

[0016] Furthermore, before purifying the steam condensate by the water purification system, the method further includes the following step: performing heat exchange and temperature reduction treatment on the steam condensate by a heat exchanger.

[0017] By applying the technical solution of the present invention, the water quality monitoring system performs quality detection on the steam condensate collected by the water recovery device in real time, and classifies the detected water quality so as to purify the steam condensate of corresponding water quality through different water quality purification systems. The primary purification system removes simple suspended matter, particulate matter, organic matter and chloride ion impurities from qualified water that meets the requirements of TDS and TOC at the same time through a sand filter device and a carbon filter device, and the secondary purification system removes suspended matter, particulate matter, organic matter, chloride ion impurities, microorganisms, bacteria and viruses from treated water that does not meet at least one of the requirements of TDS and TOC through a sand filter device, a carbon filter device, an ultrafiltration device and a reverse osmosis device. After the steam condensate is purified, the purified steam condensate is collected and stored by a water collection device. By combining the use of a water recovery device, a water purification system, a water collection device and a water quality monitoring system, the water quality can be selectively and comprehensively purified to reduce water treatment costs and water use costs. It can effectively remove suspended matter and large particle impurities, as well as organic matter and soluble solids. The purification process not only protects the boiler equipment from corrosion and scaling, but also improves the recycling rate of water resources, and solves the problems of incomplete treatment of impurities in steam condensate water and poor steam condensate recycling and utilization in the prior art, thereby achieving efficient, economical and green steam condensate recycling and reuse. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0019] Figure 1 A schematic structural diagram of an embodiment of a steam condensate treatment system according to the present invention is shown;

[0020] Figure 2 A flow chart showing an embodiment of a method for treating steam condensate according to the present invention. DETAILED DESCRIPTION

[0021] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0022] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0023] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein, for example. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0024] Now, exemplary embodiments according to the present application will be described in more detail with reference to the accompanying drawings. However, these exemplary embodiments may be implemented in a variety of different forms and should not be construed as being limited to the embodiments described herein. It should be understood that these embodiments are provided to make the disclosure of the present application thorough and complete, and to fully convey the concepts of these exemplary embodiments to those of ordinary skill in the art. In the accompanying drawings, for the sake of clarity, the thickness of the layers and regions may be enlarged, and the same reference numerals are used to represent the same devices, and thus their descriptions will be omitted.

[0025] Combination Figure 1 As shown, according to a specific embodiment of the present application, a steam condensate treatment system is provided.

[0026] Specifically, Figure 1 As shown, the treatment system includes a water recovery device, a water purification system, a water collection device and a water quality monitoring system. The water recovery device is used to collect steam condensate; the water quality monitoring system is used to monitor the water quality parameters of the steam condensate; the water purification system includes at least a primary purification system and a secondary purification system, the primary purification system includes at least a sand filter device and a carbon filter device, the secondary purification system includes at least a sand filter device, a carbon filter device, an ultrafiltration device and a reverse osmosis device, the water purification system is used to purify the steam condensate, and the primary purification system and the secondary purification system are both selectively connected to the water recovery device; the water collection device is used to store the steam condensate purified by the water purification system.

[0027] By applying the technical solution of this embodiment, the water quality monitoring system performs quality detection on the steam condensate collected by the water recovery device in real time, and classifies the detected water quality so as to purify the steam condensate of corresponding water quality through different water quality purification systems. The primary purification system removes simple suspended matter, particulate matter, organic matter and chloride ion impurities from qualified water that meets the requirements of TDS and TOC at the same time through a sand filter device and a carbon filter device, and the secondary purification system removes suspended matter, particulate matter, organic matter, chloride ion impurities, microorganisms, bacteria and viruses from treated water that does not meet at least one of the requirements of TDS and TOC through a sand filter device, a carbon filter device, an ultrafiltration device and a reverse osmosis device. After the steam condensate is purified, the purified steam condensate is collected and stored by a water collection device. By combining the use of a water recovery device, a water purification system, a water collection device and a water quality monitoring system, the water quality can be selectively and comprehensively purified to reduce water treatment costs and water use costs. It can effectively remove suspended matter and large particle impurities, as well as organic matter and soluble solids. The purification process not only protects the boiler equipment from corrosion and scaling, but also improves the recycling rate of water resources, and solves the problems of incomplete treatment of impurities in steam condensate water and poor steam condensate recycling and utilization in the prior art, thereby achieving efficient, economical and green steam condensate recycling and reuse.

[0028] It should be understood that the water quality monitoring system in the present embodiment can be used for water quality monitoring of each device in the treatment system and water quality monitoring in the connecting pipes between the devices, such as water quality monitoring of the water inlet and outlet of the water recovery device, water quality monitoring of the water inlet and outlet of the water purification system, and water quality monitoring of the water inlet and outlet of the water collection device. That is to say, the water quality monitoring system in the present embodiment is a water quality monitoring of the entire treatment process of steam condensate in the treatment system, and is not limited to a certain device or a certain treatment step.

[0029] It should be noted that the steam condensate collected by the water recovery device is the steam condensate of the user. The pollutants in the steam condensate mainly include chloride ions, organic pollutants, TDS (Total Dissolved Solids) and TOC (Total Organic Carbon). The chlorine-containing organic matter is mainly chloromethylpyridine and chlorinated fat pollution. The high temperature chloride ion pollution will cause serious corrosion to carbon steel. Therefore, the water recovery device needs to be made of corrosion-resistant materials. Preferably, the water recovery device can be a carbon steel storage tank, a stainless steel storage tank and a titanium storage tank. TDS is mainly calcium and magnesium ion pollution, which will cause scaling and blockage to the internal pipes.

[0030] Optionally, the sand filter device uses the filtering effect of quartz sand, activated carbon, anthracite or manganese sand to intercept suspended solids and large particles of impurities in the water. The carbon filter device can be an aluminum honeycomb, a plastic honeycomb, a paper honeycomb or an activated carbon filter element, etc., which uses the high adsorption capacity of activated carbon to adsorb small molecular organic matter and chloride ions. The ultrafiltration system can be a combination of one or more of a flat filter membrane, a tubular ultrafiltration membrane, a capillary ultrafiltration membrane, a central control fiber ultrafiltration membrane, a porous ultrafiltration membrane, an immersion ultrafiltration membrane and a ceramic membrane. Preferably, the ultrafiltration system uses a tubular ultrafiltration membrane. The reverse osmosis device is composed of one or more reverse osmosis membrane groups, which use extremely small pore sizes to remove most of the TDS, organic matter, bacteria, viruses and microorganisms in the water.

[0031] Specifically, Figure 1 As shown, the water collection device includes a first water production tank and a second water production tank. The first water production tank is used to store steam condensate after purification by the primary purification system, and the second water production tank is used to store steam condensate after purification by the second water production tank. By setting the first water production tank and the second water production tank, qualified water and treated water can be stored separately after being purified to different degrees, which is convenient for subsequent selection and use according to different needs, thereby improving the refined management and utilization efficiency of water resources and avoiding waste of resources. For example, the primary purified water in the first water production tank can be used for cooling the equipment, and the deep purified water in the second water production tank can be used for controlling the reaction process and disinfecting and cleaning the equipment.

[0032] Furthermore, the treatment system also includes a blending device, the water outlet of the blending device is connected to the secondary purification system, the blending device has a first water inlet and a second water inlet, and the first water inlet is selectively connected to the water recovery device; wherein the second water inlet is used to introduce matching water, and the matching water is used to be mixed with the steam condensate entering the blending device. The first water inlet is selectively connected to the water recovery device according to the results of the TDS and TOC tests on the steam condensate by the water quality monitoring system in the water recovery device. When the test result of the steam condensate is treated water, the first water inlet is connected to the water recovery device, and the treated water enters the blending device, and then the matching water is introduced into the blending device through the second water inlet for mixing with the steam condensate, so that the TDS and TOC concentrations of the mixed water after mixing reach the preset threshold value, so as to ensure the efficiency and effect of the subsequent ultrafiltration and reverse osmosis treatment. After the treated water and the matching water are fully mixed, they are introduced into the secondary purification system for treatment. Specifically, if Figure 1 As shown, the compatible water can be system water, purified water, biochemical effluent, water production sewage and other external water.

[0033] It should be noted that, according to the specific results of TDS and TOC detected by the water quality monitoring system on steam condensate, the system can automatically determine whether it is necessary to introduce matching water, and the amount and type of matching water introduced can be confirmed according to the TDS and TOC content in the steam condensate and the target water quality. For example, if the TDS of the steam condensate is too high, biochemical effluent with lower TDS can be introduced for dilution; if the TOC of the steam condensate is too high, system water or sewage with lower TOC can be introduced.

[0034] Furthermore, the treatment system also includes a heat exchanger, which is used to exchange heat and cool the steam condensate. The heat of the steam condensate at a higher temperature (such as 80-93°C) is exchanged through the heat exchanger, and the heat of the steam condensate is used to preheat the primary water entering the boiler, thereby reducing the steam consumption of the boiler deaerator and reducing the temperature of the steam condensate to a temperature suitable for the sand filtration, activated carbon, ultrafiltration and reverse osmosis membrane process requirements.

[0035] In the embodiment of the present application, when the steam condensate is the steam condensate of the boiler, the recycled steam condensate can be used for the boiler, and the heat exchanger can be a water inlet preheater of the boiler. Specifically, the heat exchanger can be any one of an immersed coil heat exchanger, a plate heat exchanger, and a shell and tube heat exchanger. The heat exchanger should have a certain corrosion resistance. Preferably, the heat exchanger is a titanium shell and tube heat exchanger.

[0036] Combination Figure 2 As shown, according to another specific embodiment of the present application, a method for treating steam condensate is also provided. The method is based on the steam condensate treatment system in the above embodiment, and the method includes the following steps:

[0037] Step S10: monitoring water quality parameters of steam condensate in the water recovery device, the water quality parameters including at least one of the following: TOC, TDS, turbidity, ammonia nitrogen, total nitrogen, free chlorine;

[0038] Specifically, the water quality parameters of the steam condensate are detected by the water quality monitoring system. In addition to the above parameters, the water quality parameters may also include other parameters such as chloride ions and microorganisms.

[0039] Step S12: When it is determined that the water quality parameters meet the preset purification conditions, the steam condensate is purified by the water purification system, and the purified steam condensate is stored in the water collection device.

[0040] Specifically, the water purification system has a primary purification system and a secondary purification system. The primary purification system and the secondary purification system have different preset purification conditions for the water quality parameters of the corresponding purified water. The steam condensate is classified according to the detected steam condensate water quality parameters, the steam condensate whose water quality parameters meet the preset purification conditions is purified, and the purified water is stored.

[0041] It should be noted that steam condensate can be classified into qualified water, treated water and discharged water according to different TOC and TDS values. Among them, qualified water is passed into the primary purification system for purification; treated water is passed into the secondary purification system for purification; and discharged water is passed into the sewage pool for collection and treatment. After the qualified water and treated water are purified at the primary and secondary levels respectively, they are collected and stored in the water collection device for subsequent use.

[0042] Through the above steps, the water quality parameters of the steam condensate in the water recovery device are monitored, and the water quality parameters include at least one of the following: TOC, TDS; when it is determined that the water quality parameters meet the preset purification conditions, the steam condensate is purified by the water purification system, and the purified steam condensate is stored in the water collection device. The most suitable purification process can be automatically selected according to the degree of contamination of the condensate, which effectively improves the recycling rate of water resources, reduces the processing cost, and has economic and green environmental protection benefits.

[0043] Optionally, the water quality parameters include at least TOC and TDS, and the method further comprises the following steps:

[0044] Step S14: When it is determined that the water quality parameters meet the preset discharge conditions, the steam condensate is discharged into the sewage pool;

[0045] Specifically, the water quality parameters are divided into preset purification conditions and preset discharge conditions, wherein the preset purification conditions are further divided into the first purification conditions and the second purification conditions. The steam condensate is classified according to the three levels of water quality parameters, so that the system has a clear division of labor and higher efficiency.

[0046] The preset discharge conditions are TDS>1000ppm and / or TOC>150ppm. Setting the preset discharge conditions to high TDS and high TOC conditions ensures that only seriously polluted condensate will be discharged into the sewage pool, reducing the negative impact of sewage on the environment while ensuring the normal operation of the system.

[0047] Optionally, the water quality parameters include at least TOC and TDS. In step S12, when it is determined that the water quality parameters meet the preset purification conditions, the steam condensate is purified by the water purification system, and the purified steam condensate is stored in the water collection device, including the following steps:

[0048] Step S121: When it is determined that the water quality parameter meets the first purification condition in the preset purification conditions, the steam condensate is purified by the primary purification system, and the purified steam condensate is stored in the first water production tank;

[0049] Specifically, when the water quality parameters of the steam condensate meet the first purification conditions, it is purified by a first purification system, which at least includes sand filtration and carbon filtration processes.

[0050] Among them, the first purification condition is TDS≤50ppm and TOC≤10ppm. The TDS and TOC content of the first purification condition is relatively low, that is, the water quality of the steam condensate is relatively good, and it can meet the recycling standard only through simple purification steps. Therefore, fewer purification process steps are set, and the TDS and TOC can meet the target standards after sand filtration and carbon filtration, and the purified steam condensate is stored in the first water production tank for recycling.

[0051] Optionally, in step S12, when it is determined that the water quality parameters meet the preset purification conditions, the steam condensate is purified by a water purification system, and the purified steam condensate is stored in a water collection device, further comprising the following steps:

[0052] Step S122: When it is determined that the water quality parameter meets the second purification condition in the preset purification condition, the steam condensate is purified by the secondary purification system, and the purified steam condensate is stored in the second water production tank;

[0053] Specifically, when the water quality parameters of the steam condensate meet the second purification conditions, it is purified by a second purification system, which at least includes sand filtration, carbon filtration, ultrafiltration and reverse osmosis processes.

[0054] Among them, the second purification condition is 50≤TDS≤1000ppm, and / or, 10ppm≤TOC≤150ppm. When at least one of the TDS and TOC of the first purification condition reaches the intermediate content, the steam condensate is subjected to the second purification treatment. Since the water quality pollution degree of the steam condensate is moderate in this case, the steam condensate is treated by setting up a second purification system with relatively more treatment processes. The four sand filtration, carbon filtration, ultrafiltration and reverse osmosis processes can be used in combination to ensure that the water quality is fully purified, which can effectively remove suspended matter and large particle impurities, and can also remove organic matter and soluble solids, so that the purified steam condensate meets the target standard, and the purified steam condensate is stored in the second water production tank for recycling.

[0055] Optionally, in step S122, before purifying the steam condensate by the secondary purification system, the method further includes the following steps:

[0056] Step S1221: the steam condensate is prepared by a preparation device so that the steam condensate meets the third purification condition;

[0057] Specifically, when the water quality of the steam condensate meets the second purification condition, the chemical properties of the steam condensate are adjusted by introducing compatible water and mixing it with the steam condensate, so that the water quality reaches the third purification condition, which can facilitate further purification of the steam condensate.

[0058] Among them, the third purification condition is TDS≤340ppm and TOC≤150ppm. The compatible water can be various types of water, including system water, purified water, biochemical water or sewage. Selecting the appropriate compatible water can effectively control the concentration of TDS and TOC in the mixed water body. Through the deployment, it does not waste water resources, but can effectively adjust the chemical characteristics of the steam condensate water, so that it becomes recyclable qualified water after purification by the second purification system, which improves the stability and reliability of the entire water treatment system, and also improves the flexibility and efficiency of the system, and reduces the treatment cost.

[0059] Optionally, in step S12, before purifying the steam condensate by the water purification system, the method further includes the following steps:

[0060] Step S11: heat exchange and temperature reduction treatment of steam condensate is performed through a heat exchanger.

[0061] Specifically, the heat exchanger cools down the initially collected high-temperature steam condensate and recycles the heat. The use of the heat exchanger not only protects subsequent processing equipment, but also optimizes the energy efficiency of the entire water treatment process.

[0062] The steam condensate treatment system and method in the above embodiment have the following beneficial effects:

[0063] 1) Effectively utilize the waste heat of steam condensate to preheat the boiler inlet water, reduce the heating energy consumption of the deaerator in the boiler device, and improve the utilization rate of thermal energy.

[0064] 2) Use online monitoring and program control to recycle and reuse water of different qualities in different ways, and ensure the stable operation of subsequent equipment under the premise of strengthening water quality control.

[0065] 3) It can recover steam condensate according to different water qualities, utilize other unqualified water resources, improve water resource utilization, strengthen the internal water cycle of the enterprise, and establish a green economic system;

[0066] 4) Steam condensate recovery and utilization method After monitoring and judging the steam condensate of different water qualities, different recovery methods are adopted for different water qualities, which effectively simplifies the steam condensate treatment process, reduces the steam condensate treatment cost, and improves the economic benefits of water recycling.

[0067] The present application also provides a preferred embodiment of a steam condensate treatment method, which can effectively remove chloride ions, organic matter and TDS in the steam condensate and recycle the steam condensate:

[0068] Step 1: The steam condensate generated by the user is recovered and enters a water recovery device with an anti-corrosion coating. At this time, the temperature of the water recovery device is controlled at 60-98°C, preferably 85-98°C, and the pressure of the water recovery device is 0-0.125MPa, preferably 0-0.055MPa;

[0069] Step 2: Use a heat exchanger to cool down the steam condensate. The temperature of the steam condensate after cooling is 25-55°C. Perform online TDS and TOC monitoring on the steam condensate after cooling. Determine the steam condensate according to the concentration of TDS and TOC. Determine the steam condensate that meets the conditions of TDS≤50ppm and TOC≤10ppm as qualified water, and jump to step 3; Determine the steam condensate that meets the conditions of 50≤TDS≤1000ppm, and / or, 10ppm≤TOC≤150ppm as treated water, and jump to step 4; Determine the steam condensate that meets the conditions of TDS>1000ppm, and / or, TOC>150ppm as discharge water, and jump to step 5;

[0070] Among them, the cooling of steam condensate can be temperature-controlled and adjusted according to the season and water production; the water treatment system can be operated continuously or intermittently; the monitoring frequency of TOC of steam condensate is preferably online monitoring.

[0071] Step 3: Qualified water is passed into the first purification system for sand filtration and carbon filtration, and then passed into the first water production tank for storage;

[0072] Step 4: Pass the treated water into the blending device, pass the blending water into the treated water, adjust the chemical properties and TDS and TOC concentrations of the treated water, so that it meets the conditions of TDS ≤ 340ppm and TOC ≤ 150ppm, and then pass it into the second purification system for sand filtration, carbon filtration, ultrafiltration and reverse osmosis treatment, and then pass it into the second water production tank for storage;

[0073] Among them, the TDS and TOC concentrations can be adjusted by mixing water, or by adding a variety of reagents to achieve the target concentration.

[0074] Step 5: Drain the discharged water into a sewage pool for collection and treatment.

[0075] The effects of the technical treatment of the steam condensate recovery method are compared through different embodiments and comparative examples:

[0076] Example 1

[0077] The steam condensate from the user is recovered to the steam condensate recovery device. The temperature of the recovery device is 92°C and the pressure is atmospheric pressure. It is pumped to the water inlet preheater. After heat exchange, the temperature of the steam condensate drops to 52°C. Online sampling and testing; liquid phase mass spectrometry analysis shows that the steam condensate contains a certain amount of chlorine-containing organic matter, with a content of about 1 to 160 ppm, mainly chloromethyl pyridine and chlorinated fat pollution; water quality analysis and judgment are collected, and the monitoring data of a company's 12h operation on the same day (hourly average) are collected, as shown in Table 1 below:

[0078] Table 1:

[0079] time TOC / ppm TDS / ppm Judgment result Flow rate t / h 0:00 1.2 8 Qualified water 79 1:00 4.6 16 Qualified water 81 2:00 0.8 9 Qualified water 80 3:00 1.2 28 Qualified water 80 4:00 6.2 36 Qualified water 83 5:00 11 32 Qualified water 82 6:00 33 108 Treating water 81 7:00 48 122 Treating water 80 8:00 59 214 Treating water 80 9:00 46 103 Treating water 81 10:00 59 144 Treating water 81 11:00 42 96 Treating water 80 12:00 42 122 Treating water 81

[0080] From the statistics in Table 1, it can be seen that the water quality fluctuation of steam condensate increases. If it is directly reused in the boiler, chlorine-containing organic matter will directly enter the boiler. Under high temperature, it may cause corrosion to key parts such as the boiler water cooling screen, steam drum and deaerator, shortening the service life of the equipment. In severe cases, it may cause pipe burst and cause boiler shutdown.

[0081] This part of water enters the water treatment system. The first 5 hours of water is qualified water. After sand filtration, the sand filter operating pressure is ≤0.1MPa, the water recovery rate is 99.3%, the carbon filter operating pressure is <0.36MPa, and the water recovery rate is 99.8%. Then it enters the first water production tank, about 514t. After testing, the water quality of the first water production tank is as follows: TOC: 0.9ppm, TDS: 18ppm. After 7 hours, the water system is determined to be treated water. After mixing with 430t of external supply system water, it passes through sand filtration with an operating pressure of 0.25MPa~0.4MPa, and the carbon filter operating pressure is 0.25MPa~0.45MPa. Then it passes through the ultrafiltration device with an operating pressure of 0.2MPa~0.4MPa. Finally, after a single reverse osmosis, the water recovery rate can reach 45%~83%. The concentrated water can be sent to biochemical treatment, and the effluent can be used as mixing water and reused in the boiler. After treatment, the water enters the second water tank, about 567 tons. After testing, the water quality of the second water tank is as follows: TOC: 0.4ppm, TDS: 10ppm. The outlet water meets the water demand of the boiler.

[0082] Embodiments 2 to 8

[0083] According to Example 1, the water quality of the recovered steam condensate may fluctuate greatly, and the existing program control system will switch the valve after judging according to the set value. The following statistical judgment logic sets the average values ​​of different time periods: 1h, 2h, 3h, 5h, 8h, 12h and 24h detection average values ​​as judgment conditions, and examines the operation of the judgment system and the water output index.

[0084] Table 2:

[0085]

[0086] As can be seen from Table 2, when the system is set to the average value of 1h, 2h and 3h, the system can separate the qualified water and treated water in the recovered steam condensate and reuse them. When the set time is ≥5h, the system determines that the recovered steam condensate is all treated water. After mixing with the external supply system water and after treatment, the water can be recycled to the boiler.

[0087] Embodiments 9 to 14

[0088] Use treated water to regulate the temperature of the recovered steam condensate in the heat exchanger in the recovery system. Investigate the water production rate under the same treatment conditions at different temperatures. Take the recovered steam condensate, send it for sample testing, add a certain amount of chloroester, calcium chloride and magnesium chloride, and configure the recovered steam condensate with TOC of 50ppm and TDS of 300. Control the water temperature to 10℃, 15℃, 20℃, 25℃, 35℃, 45℃ respectively, and enter the sand filtration, carbon filtration, ultrafiltration and reverse osmosis system under the same operating conditions for treatment. Each batch runs 200L of water. The results are shown in Table 3 below:

[0089] Table 3:

[0090]

[0091] Note: The cleaning of the membrane group is mainly for ultrafiltration and reverse osmosis. When the pressure difference exceeds 0.08MPa, flushing and backwashing should be carried out in time.

[0092] As can be seen from Table 3 above, when the inlet water temperature is too low, the water treatment system is limited by the low temperature of the membrane group, and the water production rate is only 50%. At the same time, the frequency of membrane group cleaning is also high, but the water quality is better at low temperatures. As the temperature rises, the water production rate increases significantly, but the TOC and TDS in the water also increase. When the processing temperature is 45°C, the TOC and TDS increase significantly when the steam condensate is recovered. Therefore, the temperature of the recovered steam condensate is preferably 20°C to 35°C. The treated steam condensate meets the boiler water demand.

[0093] Embodiments 10 to 13

[0094] According to Example 1 and Example 9, two types of recovered steam condensate with high TOC (TOC is about 156ppm, TDS is 400ppm) and high TDS (TOC is about 32ppm, TDS is about 664ppm) were collected. The high TOC steam condensate uses water production wastewater (mainly containing calcium and magnesium ions) to dilute the TOC to 50ppm, and the high TDS steam condensate uses biochemical effluent (TOC is about 40ppm, TDS is 122ppm) to dilute the TDS to 300ppm. Using the experimental device in Example 9, the experiment was carried out under the same operating conditions to compare the actual recovery and treatment of steam condensate (TOC: 50ppm, TDS: 300ppm), the water temperature is 35°C, and the water distribution results are shown in Table 4 below:

[0095] Table 4:

[0096]

[0097] The experimental results are shown in Table 5 below:

[0098] Table 5:

[0099]

[0100] From Table 5 above, we can see that after the treated water is mixed, the produced water can fully meet the boiler water demand. After the organic matter in the biochemical effluent is biochemically treated, it is basically small molecular organic matter, which has a high permeability in the membrane group, resulting in a high TOC in the produced water. The TDS in the water treatment wastewater is mainly provided by calcium and magnesium ions, which leads to a high TDS in the produced water.

[0101] Embodiments 14 to 15

[0102] In order to compare the heat energy saving effect of the present application, if normal temperature primary pure water is used directly, the deaerator is heated with self-produced steam. According to the implementation steps in Example 1, the primary pure water directly enters the deaerator, and the heat energy saving is compared by comparing the steam consumption of the deaerator. The steam condensate from the user is recovered to the steam condensate recovery tank, the recovery tank temperature is 92°C, and the pressure is normal pressure. It is pumped to the water inlet (pressure 0.35MPa) preheater, and after heat exchange with the primary pure water, it enters the raw water tank. The current load of the boiler is 65% to 75%, the water consumption is 90t / h to 113t / h, the deaerator temperature is 100°C, and the primary pure water inlet pressure is 0.41MPa.

[0103] Table 6:

[0104]

[0105] Through the two embodiments in Table 6, the steam recovery condensate is used to heat the primary pure water, and then enters the boiler deaerator, which can effectively save the steam consumption of the deaerator. Compared with directly entering the primary pure water at room temperature, the heat energy in the steam condensate can be effectively utilized after the steam condensate is recovered for heat exchange, and the annual steam saving effect is obvious. It is conducive to realizing the recycling of water resources in the enterprise and the recycling of heat energy. At the same time, the water pressure entering the deaerator is much greater than the water exchange water pressure, which avoids the mutual cross-talk of the medium caused by the perforation of the heat exchanger, causing water source pollution.

[0106] Comparative Example 1

[0107] The water treatment system accommodates a TOC range of 10 to 150 ppm and a TDS range of 50 to 1000 ppm. Two groups of steam condensate water exceeding 1.5 times this range were selected for the experiment. The effluent quality was studied using the water treatment system of the invention at an inlet water temperature of 35 degrees, as shown in Table 7.

[0108] Table 7:

[0109]

[0110] When the TOC in the recovered steam condensate rose to about 1.5 times, the activated carbon adsorption saturation phenomenon occurred, the TOC produced by the membrane group reached 42ppm, and it could not be reused in the boiler, and the water production rate also dropped significantly. During this process, 200L of water was treated and 7 backwashings were performed. At the same time, after the operation was completed, during the cleaning of the equipment, it was found that a certain amount of organic film appeared in the concentrated water of the membrane group, which had a great impact on the water production rate of the membrane. When TDS increased to about 1600ppm, the TDS of the produced water also showed a great increase, which did not meet the water demand of the boiler. When the TDS in the boiler inlet water was high, it would cause frequent corrosion under the boiler scale, seriously affecting the stable operation of the boiler. Compared with high-organic steam condensate, the high TDS water production rate dropped more and more obviously. In the treatment of 200L steam condensate, 12 backwashings were performed. At the same time, when the reverse osmosis membrane group was disassembled and cleaned, white solids were found in the concentrated water, which were detected as calcium and magnesium precipitates.

[0111] Therefore, within the required range, a variety of water can be used to mix and reuse steam condensate, which has good applicability in industry. At the same time, the water treatment system can add reaction tanks and sedimentation tanks to the treatment system to further treat the high calcium and magnesium water system. Add Fenton oxidation and advanced oxidation systems to treat high TOC water systems. Expand the types of water that can be reused, strengthen the construction of the enterprise's water circulation system, reuse the reclaimed water of various wastewaters, reduce the water intake cost of the enterprise, and reduce costs and increase efficiency.

[0112] Comparative Example 2

[0113] In the process of using heat exchangers to heat steam condensate, plate heat exchangers and shell-and-tube heat exchangers were used to heat primary pure water. Among them, the heat medium inlet pressure of the plate heat exchanger increased after one month of operation, and showed an upward trend. At the same time, the outlet temperature of primary pure water showed a significant downward trend, and the statistical data is shown in Table 8 below:

[0114] Table 8:

[0115] Run time Steam condensate inlet pressure Primary pure water outlet temperature 0d 0.350MPa 75℃ 12d 0.354MPa 74℃ 20d 0.358MPa 72℃ 30d 0.365MPa 72℃ 60d 0.379MPa 66℃

[0116] The heat exchanger showed a decrease in heat exchange efficiency. The plate heat exchanger was disassembled and cleaned, and light red and black solids were found inside. The detection was mainly iron-containing impurities. The reason may be that the user uses carbon steel material, which causes a certain amount of iron ions in the water system. Under pH changes, corresponding precipitates are formed, causing the heat exchanger to be blocked. At the same time, in the sand filter and carbon filter systems, red solids also appeared in the concentrated water. The stable operation time of the purification system is seriously shortened, and the cleaning frequency of the two filtering devices is increased. On the basis of this application, a precision filter is added to the outlet of the steam condensate recovery tank pump, and a filter element is used for filtering. The filtered steam condensate enters the purification system of the present invention again, and the heat exchanger has been running stably for 124 days. The pressure of the heat exchanger, sand filter and carbon filter system in the invention has not increased. By experimenting with various forms of filters, such as disc filters and bag filters, the filtering effect can be achieved as long as a certain mesh number is met.

[0117] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0118] In addition to the above, it should be noted that "one embodiment", "another embodiment", "embodiment", etc. mentioned in this specification refer to the specific features, structures or characteristics described in conjunction with the embodiment included in at least one embodiment generally described in this application. The same expression appearing in multiple places in the specification does not necessarily refer to the same embodiment. Further, when describing a specific feature, structure or characteristic in conjunction with any embodiment, it is claimed that the realization of such feature, structure or characteristic in conjunction with other embodiments also falls within the scope of the present invention.

[0119] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0120] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A steam condensate treatment system, characterized in that: The processing system comprises: A water recovery device, wherein the water recovery device is used to collect steam condensate; A water quality monitoring system, wherein the water quality monitoring system is used to monitor water quality parameters of the steam condensate; A water purification system, the water purification system at least comprising a primary purification system and a secondary purification system, the primary purification system at least comprising a sand filter device and a carbon filter device, the secondary purification system at least comprising a sand filter device, a carbon filter device, an ultrafiltration device and a reverse osmosis device, the water purification system is used to purify the steam condensate, and the primary purification system and the secondary purification system are both selectively connected to the water recovery device; A water collecting device is used to store steam condensate after being purified by the water purification system.

2. The steam condensate treatment system according to claim 1, characterized in that: The water collection device includes a first water production tank and a second water production tank. The first water production tank is used to store the steam condensate after purification by the primary purification system, and the second water production tank is used to store the steam condensate after purification by the second water production tank.

3. The steam condensate treatment system according to claim 2, characterized in that: The processing system further comprises: A mixing device, wherein the water outlet of the mixing device is connected to the secondary purification system, the mixing device has a first water inlet and a second water inlet, and the first water inlet is selectively connected to the water recovery device; Wherein, the second water inlet end is used for introducing matching water, and the matching water is used for matching with the steam condensate entering the matching device.

4. The steam condensate treatment system according to claim 1, characterized in that: The processing system further comprises: A heat exchanger is used to exchange heat and cool the steam condensate.

5. A method for treating steam condensate, characterized in that: The method is carried out based on the steam condensate treatment system according to any one of claims 1 to 4, and the method comprises: Monitoring water quality parameters of steam condensate in the water recovery device, wherein the water quality parameters include at least one of the following: TOC, TDS, turbidity, ammonia nitrogen, total nitrogen, and free chlorine; When it is determined that the water quality parameters meet the preset purification conditions, the steam condensate is purified by the water purification system, and the purified steam condensate is stored in the water collection device.

6. The method for treating steam condensate according to claim 5, characterized in that: The water quality parameters include at least TOC and TDS, and the method further comprises the following steps: When it is determined that the water quality parameters meet the preset discharge conditions, the steam condensate is discharged into a sewage pool; Wherein, the preset emission conditions are TDS>1000ppm and / or TOC>150ppm.

7. The method for treating steam condensate according to claim 5, characterized in that: The water quality parameters at least include TOC and TDS. When it is determined that the water quality parameters meet the preset purification conditions, the steam condensate is purified by the water purification system, and the purified steam condensate is stored in the water collection device, including the following steps: When it is determined that the water quality parameter meets the first purification condition in the preset purification conditions, the steam condensate is purified by the primary purification system, and the purified steam condensate is stored in the first water production tank; Wherein, the first purification condition is TDS≤50ppm and TOC≤10ppm.

8. The method for treating steam condensate according to claim 7, characterized in that: When it is determined that the water quality parameters meet the preset purification conditions, the steam condensate is purified by the water purification system, and the purified steam condensate is stored in the water collection device, further comprising the following steps: When it is determined that the water quality parameter meets the second purification condition in the preset purification condition, the steam condensate is purified by the secondary purification system, and the purified steam condensate is stored in the second water production tank; Wherein, the second purification condition is 50≤TDS≤1000ppm, and / or, 10ppm≤TOC≤150ppm.

9. The method for treating steam condensate according to claim 8, characterized in that: Before purifying the steam condensate by the secondary purification system, the method further comprises the following steps: The steam condensate is prepared by a preparation device so that the steam condensate meets the third purification condition; Wherein, the third purification condition is TDS≤340ppm and TOC≤150ppm.

10. The method for treating steam condensate according to claim 5, characterized in that: Before purifying the steam condensate by the water purification system, the method further comprises the following steps: The steam condensate is subjected to heat exchange and temperature reduction treatment through a heat exchanger.

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