Boiler make-up water treatment equipment and cleaning method for same

Abstract

The invention discloses boiler make-up water treatment equipment and a cleaning method for the boiler make-up water treatment equipment. The boiler make-up water treatment equipment comprises a clarification tank, a variable-porosity filter tank, a raw water heater, a raw water tank, a double-medium filter, an ultrafiltration security filter, an ultrafiltration device, an ultrafiltration water tank, a reverse osmosis security filter, a first-stage reverse osmosis system, a first-stage fresh water tank, a second-stage reverse osmosis system, a second-stage fresh water tank, a mixed bed and a demineralized water tank which are sequentially connected through pipelines, wherein the first-stage reverse osmosis system and the second-stage reverse osmosis system are connected with a cleaning device; the cleaning method comprises the steps of cleaning device starting, water washing, alkali washing, acid washing and waste liquid treatment. The method is easy to operate, high in practicability and good in effect, according to the water quality of a water source and the pollution conditions of the cartridge filter element and the membrane element, the cleaning flow is increased, corresponding agents are added for cleaning, and the good cleaning effect can be achieved.

Description

Technical Field

[0001] The invention relates to the technical field of cleaning boiler feed water treatment equipment, and in particular to boiler feed water treatment equipment and a cleaning method for the equipment. Background Art

[0002] At present, many thermal power plants use urban reclaimed water as the source of industrial water. The quality of reclaimed water is richer in microorganisms and heavy metals than groundwater and surface water, which is the main cause of reverse osmosis fouling. The working principle of reverse osmosis is: adding a pressure higher than the osmotic pressure to the concentrated solution side will press the solvent (water) in the concentrated solution to the dilute solution side. When purifying water using this principle, a higher pressure must be applied to the concentrated water side. Reverse osmosis is used to purify raw water, which is low-cost and easy to maintain. It is widely used in water purification in various industries. However, with the long-term operation of reverse osmosis, the impurities intercepted cannot be washed down and need to be shut down for cleaning. Traditional acid washing and alkali washing have poor effects, so the membrane elements are forced to be dismantled and sent to a professional cleaning company for cleaning. Cleaning a set of reverse osmosis costs 50,000 yuan, which is time-consuming, labor-intensive and costly.

[0003] The Chinese invention patent with publication number CN 106659980 A discloses an attachment monitoring device for a water treatment device, a water treatment device and an operation method thereof, and a cleaning method for the water treatment device. The attachment monitoring device for a water treatment device of the present invention comprises: an impermeable water pipeline (L11), which discharges impermeable water (15) obtained by concentrating dissolved components and dispersed components from a separation membrane device, wherein the separation membrane device obtains permeable water by concentrating dissolved components and dispersed components from treated water (11) through a separation membrane; a first attachment detection unit (24A), which is arranged in an impermeable water branch pipeline (L12) branched from the impermeable water pipeline (L11), The invention also comprises a first detection separation membrane (21A) which uses a part of the branched non-permeable water as a detection liquid (15a) and separates the detection liquid (15a) into detection permeable water (22) and detection non-permeable water (23); an attachment condition changing device which changes the attachment condition of the attachment attached to the first detection separation membrane (21A); and a first detection separation liquid flow rate measuring device which measures the flow rate of either or both of the detection permeable water (22) or the detection non-permeable water (23) separated in the first detection separation membrane (21A). This solution is technically complex and requires high professional skills, and the material cost used is high.

[0004] Therefore, developing a new cleaning method to loosen the silica scale and organic attachments retained by the membrane elements and remove them, which has low cost and good cleaning effect, is of great practical significance for improving reverse osmosis efficiency. Summary of the invention

[0005] The problem addressed by the present invention is that currently many industrial water treatment equipments in thermal power plants need to be disassembled and sent to cleaning companies for cleaning when faced with pollution and blockage, which is time-consuming and labor-intensive, affects normal operation and is very expensive.

[0006] In order to solve the above technical problems, one aspect of the present application provides a boiler feed water treatment equipment, including: a pretreatment system, including a clarification tank, a variable pore filter, a raw water heater, a raw water tank, a dual-media filter, an ultrafiltration safety filter, an ultrafiltration device, an ultrafiltration water tank and a reverse osmosis safety filter connected in sequence via pipelines, a lifting pump is provided on the connecting pipeline between the urban water treatment plant and the clarification tank, a raw water pump is provided on the connecting pipeline between the variable pore filter and the raw water heater, a filtration ultrafiltration feed water pump is provided on the connecting pipeline between the raw water tank and the dual-media filter, and a clean water pump is provided between the ultrafiltration water tank and the reverse osmosis safety filter; a first-level reverse osmosis system, using a first-level high-pressure pump to introduce the effluent after adsorption treatment by the reverse osmosis safety filter for reverse osmosis treatment, the first-level osmosis system includes The first-stage membrane assembly and the first-stage membrane assembly, the output pipelines of the first-stage membrane assembly are respectively connected to the first-stage fresh water tank and the first-stage second membrane assembly, and the output pipelines of the first-stage second membrane assembly are respectively connected to the first-stage fresh water tank and the high-salt wastewater tank; the secondary reverse osmosis system adopts a secondary high-pressure pump to introduce the stored water in the first-stage fresh water tank for secondary reverse osmosis treatment, the secondary osmosis system includes a secondary first-stage membrane assembly and a secondary second-stage membrane assembly, the output pipelines of the secondary first-stage membrane assembly are respectively connected to the secondary fresh water tank and the secondary second-stage membrane assembly, and the output pipelines of the secondary second-stage membrane assembly are respectively connected to the secondary fresh water tank and the ultrafiltration water tank; the desalination system includes a mixed bed and a desalted water tank connected in sequence through pipelines, the stored water in the secondary fresh water tank is pumped into the mixed bed by the fresh water pump, and the desalted water produced by the mixed bed is transported to the desalted water tank;

[0007] Among them, the first-stage reverse osmosis system and the second-stage reverse osmosis system are connected with a cleaning device, and the liquid outlet of the cleaning device is respectively connected to the cleaning liquid inlet of the first-stage one-stage membrane assembly, the cleaning liquid inlet of the first-stage two-stage membrane assembly, the cleaning liquid inlet of the second-stage one-stage membrane assembly and the cleaning liquid inlet of the second-stage two-stage membrane assembly, and the cleaning liquid outlet of the first-stage one-stage membrane assembly, the cleaning liquid outlet of the first-stage two-stage membrane assembly, the cleaning liquid outlet of the second-stage one-stage membrane assembly and the cleaning liquid outlet of the second-stage two-stage membrane assembly all lead to the cleaning device; manual valves are provided on the connecting pipelines of the cleaning device; differential pressure gauges are installed between the inlets and outlets of the first-stage one-stage membrane assembly, the first-stage two-stage membrane assembly, the second-stage one-stage membrane assembly and the first-stage two-stage membrane assembly.

[0008] According to an embodiment of the present application, the water production flow rate of the primary reverse osmosis system is 50t / h-75t / h, and the water production flow rate of the secondary reverse osmosis system is 36t / h-50t / h.

[0009] According to an embodiment of the present application, the boiler feed water treatment equipment includes three sets of parallel primary reverse osmosis systems and two sets of parallel secondary reverse osmosis systems.

[0010] According to an embodiment of the present application, the first-stage one-stage membrane assembly includes fifteen membrane assemblies, each of which is filled with six membrane elements; the first-stage two-stage membrane assembly includes seven membrane assemblies, each of which is filled with six membrane elements.

[0011] According to the embodiments of the present application, the membrane element and the membrane assembly are detachably mounted, and the shape specification of the membrane element matches the cross-sectional shape of the membrane assembly.

[0012] According to an embodiment of the present application, the secondary one-stage membrane assembly includes six membrane assemblies, each of which is filled with six membrane elements; the secondary two-stage membrane assembly includes three membrane assemblies, each of which is filled with six membrane elements.

[0013] According to an embodiment of the present application, the cleaning device includes a cleaning solution tank and a cleaning filter connected to each other, a cleaning pump is provided on the output pipeline of the cleaning filter, and a heating device and a pH meter are provided in the cleaning solution tank.

[0014] According to the embodiment of the present application, a cleaning agent is added into the cleaning solution tank, and the cleaning agent is formulated accordingly according to the type of dirt.

[0015] Another aspect of the present application discloses a cleaning method for a boiler feed water treatment device as described above, characterized in that it comprises the following steps:

[0016] S1. Start: According to the display of the pressure difference meter of the primary reverse osmosis system and the secondary reverse osmosis system, start the cleaning of the corresponding membrane components;

[0017] S2. Water flushing: Use the deionized water with four times the water output of the corresponding reverse osmosis membrane module segment to circulate and flush the membrane module for 20-30 minutes from the cleaning solution tank to flush away the fluffy attachments on the surface of the membrane element;

[0018] S3. Alkaline cleaning: add water to the cleaning solution tank to 1.2-1.5 meters, heat to 32-38℃, add alkaline cleaning agent, circulate and flush the membrane module for 2-3 hours, let it stand for 10 hours, circulate and clean again for 1-2 hours, empty the alkaline cleaning solution in the cleaning solution tank, clean up the sludge brought out by the cleaning solution return water, add deionized water and circulate and flush until the cleaning solution return water is neutral;

[0019] S4. Pickling: Fill the cleaning solution tank with water to 1.2-1.5 meters, configure the acidic cleaning agent in the cleaning solution tank, circulate and flush for 2-3 hours, drain the acidic cleaning solution, add non-oxygen bactericide solution and circulate and flush for 2-3 hours, let it stand for ten hours, and then drain the cleaning solution tank; inject deionized water and circulate and flush until the cleaning solution return water is neutral;

[0020] S5: Waste liquid treatment: The waste acid liquid and alkali liquid generated by cleaning are introduced into the wastewater pool, neutralized to a pH value of 6-9, and sent to the desulfurization absorption tower.

[0021] According to the embodiment of the present application, in step S1, when the pressure difference in each section rises to 120Kpa or the water production flow rate of the corresponding membrane assembly drops to 85% of the rated flow rate, it is judged as fouling and the cleaning device is manually started.

[0022] The beneficial effects of the technical solution of the present invention compared with the prior art are:

[0023] 1. By adopting the cleaning method of the present invention, according to the water production flow rate of the first-stage reverse osmosis and the second-stage reverse osmosis and the pressure difference of each section, the corresponding reagent is added, the cleaning flow rate is adjusted, and online cleaning is implemented, which can loosen the silicon scale and organic attachments retained by the membrane element and remove them, thereby achieving a good cleaning effect. Compared with the offline cleaning used in the prior art, this application saves more than 400,000 yuan per year.

[0024] 2. After the test summary, in the five years of operation of the boiler feed water treatment equipment, 3 sets of primary reverse osmosis and 2 sets of secondary reverse osmosis were frequently blocked, the output of the primary reverse osmosis dropped to 50 t / h, and the output of the secondary reverse osmosis dropped to 36 t / h. By adopting the cleaning method of the present invention, the output of the primary reverse osmosis was restored to 75 t / h, and the output of the secondary reverse osmosis was restored to 50 t / h, both of which were able to be restored to the designed output. In addition, the application is simple to operate, highly practical and has good effects.

[0025] 3. The equipment of the present invention is based on the advanced technology of two-stage reverse osmosis plus mixed ion exchange technology, which reuses urban water as boiler water with high quality, overcomes the defect that traditional physical and chemical and biochemical treatment processes cannot recycle urban water as production line water, and solves the problems of excessive organic matter, heavy metal ions, hardness, acid-base neutralization and salt in wastewater that are difficult to solve in existing conventional ultrapure water treatment processes, affecting the water quality of ultrapure water, membrane pollution and equipment operation stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A connection diagram of a boiler feed water treatment device in an example of the present invention;

[0027] Figure 2 This is a process diagram of a cleaning method for boiler feed water treatment equipment in an example of the present invention. DETAILED DESCRIPTION

[0028] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0029] See also Figure 1 and Figure 2As shown, a boiler feed water treatment equipment is shown, including a clarifier, a variable pore filter, a raw water heater, a raw water tank, a dual-media filter, an ultrafiltration safety filter, an ultrafiltration device, an ultrafiltration water tank, a reverse osmosis safety filter, a primary reverse osmosis system, a primary fresh water tank, a secondary reverse osmosis, a mixed bed and a demineralized water tank, a lifting pump is provided on the connecting pipe between the urban reclaimed water treatment plant and the clarifier, a raw water pump is provided on the connecting pipe between the variable pore filter and the raw water heater, a filtration ultrafiltration feed water pump is provided on the connecting pipe between the raw water tank and the dual-media filter, a clean water pump is provided between the ultrafiltration water tank and the reverse osmosis safety filter, the primary reverse osmosis system and the secondary reverse osmosis system both use high-pressure pumps to introduce wastewater to be treated, and the primary reverse osmosis system and the secondary reverse osmosis system can be connected to a cleaning device. Compared with the prior art, the present application not only ensures the effective treatment of urban reclaimed water, but also avoids the high cost of offline cleaning of the reverse osmosis system, and achieves a good cleaning effect on the entire boiler feed water treatment equipment.

[0030] In this embodiment, a pretreatment system of a boiler feed water treatment equipment includes a clarification tank, a variable pore filter, a raw water heater, a raw water tank, a dual-media filter, an ultrafiltration safety filter, an ultrafiltration device, an ultrafiltration water tank and a reverse osmosis safety filter connected in sequence through pipelines. A lifting pump is provided on the connecting pipeline between the urban water treatment plant and the clarification tank, a raw water pump is provided on the connecting pipeline between the variable pore filter and the raw water heater, a filtration ultrafiltration feed water pump is provided on the connecting pipeline between the raw water tank and the dual-media filter, and a clean water pump is provided between the ultrafiltration water tank and the reverse osmosis safety filter.

[0031] Specifically, the dual-media filters are preferably connected in parallel in 5 sets, each with an output of 85 t / h; the ultrafiltration devices are preferably connected in parallel in 3 sets, each with an output of 100 t / h.

[0032] In this embodiment, the primary reverse osmosis system uses a primary high-pressure pump to introduce the effluent after adsorption treatment by the reverse osmosis safety filter for reverse osmosis treatment. The primary osmosis system includes a primary one-stage membrane assembly and a primary two-stage membrane assembly. The output pipelines of the primary one-stage membrane assembly are respectively connected to the primary fresh water tank and the primary two-stage membrane assembly, and the output pipelines of the primary two-stage membrane assembly are respectively connected to the primary fresh water tank and the high-salt wastewater pool.

[0033] Specifically, each set of primary reverse osmosis system is divided into two membrane modules connected in series. The fresh water produced by the first membrane module is collected in the primary fresh water tank, and the concentrated water produced enters the second membrane module. The fresh water produced by the second membrane module is also collected in the primary fresh water tank. The concentrated water is discharged to the high-salt wastewater pool and finally sent to the desulfurization system.

[0034] In this embodiment, the secondary reverse osmosis system uses a secondary high-pressure pump to introduce water from the primary fresh water tank for reverse osmosis treatment. The secondary osmosis system includes a secondary first-stage membrane assembly and a secondary second-stage membrane assembly. The output pipelines of the secondary first-stage membrane assembly are respectively connected to the secondary fresh water tank and the secondary second-stage membrane assembly, and the output pipelines of the secondary second-stage membrane assembly are respectively connected to the secondary fresh water tank and the ultrafiltration water tank.

[0035] Specifically, the water stored in the primary fresh water tank is pressurized by the secondary high-pressure pump and then sent to the secondary reverse osmosis system. The secondary osmosis system includes a secondary first-stage membrane assembly and a secondary second-stage membrane assembly. The fresh water produced by the secondary first-stage membrane assembly is collected in the secondary fresh water tank, and the concentrated water produced enters the secondary second-stage membrane assembly. The fresh water produced by the secondary second-stage membrane assembly is collected in the secondary fresh water tank, and the concentrated water is sent to the ultrafiltration water tank. The outlet water of the ultrafiltration water tank is pressurized by a clean water pump, and then passes through a reverse osmosis safety filter to remove particulate impurities larger than 5 microns. After being pressurized by the primary high-pressure pump again, it enters the primary reverse osmosis device for reverse osmosis treatment.

[0036] It can be understood that after the incoming water passes through the reverse osmosis membrane element of the reverse osmosis system, the water that passes through the membrane element is called fresh water, and the concentrated water containing impurities or salts that does not pass through is called concentrated water.

[0037] Specifically, the recovery rate of the primary reverse osmosis system is 75%, and the recovery rate of the secondary reverse osmosis system is 90%.

[0038] Specifically, the first-stage membrane assembly includes 15 membrane assemblies, each of which is filled with six membrane elements; the first-stage membrane assembly includes 7 membrane assemblies, each of which is filled with six membrane elements. The second-stage membrane assembly includes 6 membrane assemblies, each of which is filled with six membrane elements; the second-stage membrane assembly includes 3 membrane assemblies, each of which is filled with six membrane elements. 3 sets of first-stage reverse osmosis and 2 sets of second-stage reverse osmosis, totaling 504 membrane elements, are involved in filtering raw water.

[0039] Specifically, the membrane element and the membrane assembly can be detachably installed, and the shape and specification of the membrane element match the cross-sectional shape of the membrane assembly. The membrane element can be detached, firstly, to facilitate the replacement of damaged membrane elements, and secondly, to facilitate the extraction of impurities intercepted by the membrane element for research.

[0040] In this embodiment, the desalination system includes a mixed bed and a desalted water tank connected in sequence via pipelines. The water stored in the secondary fresh water tank is pumped into the mixed bed by a fresh water pump, and the desalted water produced by the mixed bed is transported to the desalted water tank for standby use.

[0041] Among them, the first-stage reverse osmosis system and the second-stage reverse osmosis system are connected with a cleaning device, and the liquid outlet of the cleaning device is respectively connected to the cleaning liquid inlet of the first-stage one-stage membrane assembly, the cleaning liquid inlet of the first-stage two-stage membrane assembly, the cleaning liquid inlet of the second-stage one-stage membrane assembly and the cleaning liquid inlet of the second-stage two-stage membrane assembly, and the cleaning liquid outlet of the first-stage one-stage membrane assembly, the cleaning liquid outlet of the first-stage two-stage membrane assembly, the cleaning liquid outlet of the second-stage one-stage membrane assembly and the cleaning liquid outlet of the second-stage two-stage membrane assembly all lead to the cleaning device; manual valves are provided on the connecting pipelines of the cleaning device; differential pressure gauges are installed between the inlets and outlets of the first-stage one-stage membrane assembly, the first-stage two-stage membrane assembly, the second-stage one-stage membrane assembly and the first-stage two-stage membrane assembly.

[0042] Specifically, the cleaning device includes a cleaning solution tank and a cleaning filter connected to each other. A cleaning pump is provided on the output pipeline of the cleaning filter. A manual door is provided at the outlet of the cleaning pump to adjust the flow of the cleaning solution. A heating device and a pH meter are provided in the cleaning solution tank. In the actual cleaning process, the cleaning solution tank needs to be filled with corresponding cleaning agents for multiple cycles of cleaning. The cleaning agents are formulated according to the type of dirt.

[0043] It is understandable that when cleaning the reverse osmosis system, safety considerations are taken into account, such as the poor reliability of pneumatic doors (electric doors), and the leakage of cleaning fluid will affect other reverse osmosis operations, so the reverse osmosis system needs to be separated from the entire boiler feed water treatment equipment for cleaning.

[0044] In the embodiments of the present application, the configuration of cleaning agents is the key to cleaning. Different agents need to be used according to the pollution conditions of the water source, filter element, membrane element, etc. to achieve an effective cleaning effect. Therefore, the impurities intercepted by the filter element and membrane element of the security filter are extracted in the laboratory. After drying, they are burned to produce odor, which is judged as organic pollution; when the total weight of the membrane exceeds 10% of the weight of the wet membrane, the membrane element is blocked or scaled. When the scale sample is titrated with 1% hydrochloric acid, bubbles are generated, which is judged as carbonate scale, and no bubbles are generated, which is judged as sulfate scale or silica scale. After a series of experiments, it was found that the main pollutants are carbonate scale, sulfate scale, silica scale and organic matter.

[0045] In response to the above-mentioned pollutants and blockages, the corresponding agents were found through experiments. Sodium dialkylbenzene sulfonate has a strong effect of stripping and fluffing membrane elements, sodium fluoride can dissolve deposited silica scale, citric acid can dissolve carbonate scale, hydrochloric acid can dissolve heavy metals, and non-oxygen bactericides can kill algae and sterilize. As shown in the following table, effective cleaning agents are given for carbonate scale, inorganic salt scale, silica scale, microorganisms, and organic matter:

[0046]

[0047] In the embodiment of the present application, based on the prepared cleaning agent, the present application discloses a cleaning method for the above boiler feed water treatment equipment, comprising the following steps:

[0048] S1. Startup: The control system analyzes the pressure difference and output of the primary reverse osmosis system and the secondary reverse osmosis system and starts the cleaning of the corresponding membrane components;

[0049] Specifically, in step S1, when it is observed that the pressure difference of each section rises to 120Kpa or the water production flow rate of the corresponding section membrane assembly drops to 85% of the rated flow rate, it is determined that the system is blocked and the cleaning device is manually started.

[0050] S2. Water flushing: Use the deionized water with four times the water output of the corresponding reverse osmosis membrane module to circulate and flush the membrane module for 20-30 minutes from the cleaning solution tank to flush away the fluffy attachments on the surface of the membrane element;

[0051] Specifically, according to the water production of the membrane component section of the reverse osmosis system that needs to be flushed, a corresponding amount of desalted water is added to the cleaning solution tank, the desalted water is input into the cleaning filter through a pipeline and then pumped into the cleaning liquid inlet gate of the membrane component section by a cleaning pump, the cleaning liquid is output through the cleaning liquid outlet gate of the membrane component section and then enters the cleaning solution tank, and the membrane component section is flushed multiple times in this cycle.

[0052] S3. Alkaline cleaning: add water to the cleaning solution tank to 1.2-1.5 meters, heat to 32-38℃, add the prepared alkaline cleaning agent, circulate and flush the membrane module for 2-3 hours, let it stand for 10 hours, circulate and clean again for 1-2 hours, empty the alkaline cleaning solution in the cleaning solution tank, clean up the sludge brought out by the cleaning solution return water, add deionized water and circulate and flush until the cleaning solution return water is neutral;

[0053] Specifically, water is added to the cleaning solution tank to 1.2-1.5 m, heated to 32-38° C., a 0.1% NaOH solution is prepared, and 500 g of sodium dialkylbenzene sulfonate and 500 g of sodium silicide are added to prepare an alkaline cleaning agent.

[0054] S4. Pickling: Fill the cleaning solution tank with water to 1.2-1.5 meters, configure the acidic cleaning agent in the cleaning solution tank, circulate and flush for 2-3 hours, drain the acidic cleaning solution, add non-oxygen bactericide solution and circulate and flush for 2-3 hours, let it stand for ten hours, and then drain the cleaning solution tank; inject deionized water and circulate and flush until the cleaning solution return water is neutral;

[0055] Specifically, fill the cleaning solution tank to 1.2-1.5 meters, prepare 1.5%-2% citric acid solution, add 2-3 kg of 30% hydrochloric acid solution, adjust the pH value of the cleaning solution to 2-3, and adjust the circulating flushing flow rate to 150-180 T / H.

[0056] S5: Waste liquid treatment: The waste acid liquid and alkali liquid generated by cleaning are introduced into the wastewater pool, neutralized to a pH value of 6-9, and sent to the desulfurization absorption tower.

[0057] In this embodiment, the indicators of the primary reverse osmosis system before and after cleaning are compared as follows:

[0058]

[0059] As can be seen from the table above, the cleaning method used in this application has a better cleaning effect, and the pressure difference in each section can be reduced by 30-50Kpa, and the water output is increased by 15-20T / H accordingly. According to records, the first and second level reverse osmosis are cleaned online once every six months, saving more than 400,000 yuan each year compared with offline cleaning.

[0060] Specifically, the water flow rate of the primary reverse osmosis system is 50t / h-75t / h, and the water flow rate of the secondary reverse osmosis system is 36t / h-50t / h. In this embodiment, the boiler feed water treatment equipment includes 3 sets of parallel primary reverse osmosis systems and 2 sets of parallel secondary reverse osmosis systems. In the five years since the boiler feed water treatment equipment was put into operation, 3 sets of primary reverse osmosis and 2 sets of secondary reverse osmosis were often blocked by dirt, the output of the primary reverse osmosis dropped to 50t / h, and the output of the secondary reverse osmosis dropped to 36t / h. The double-machine operation caused a shortage of desalted water, which seriously threatened the safe operation of the machine and the furnace. After investigation and analysis, new cleaning agents were added to loosen the silicon scale and organic attachments retained by the membrane elements and remove them, achieving good results. The output of the primary reverse osmosis was restored to 75t / h, and the output of the secondary reverse osmosis was restored to 50t / h, and both were able to return to the designed output.

[0061] Specifically, three sets of parallel primary reverse osmosis systems are designed to be used as backup for each other. When one set is under maintenance or cleaning, the other two sets can be operated without affecting the water treatment system. The three sets of primary reverse osmosis systems can be operated individually, or two or three sets can be operated simultaneously.

[0062] Specifically, two sets of parallel two-stage reverse osmosis systems are designed to serve as backup for each other. When one set is under maintenance or cleaning, the other set can be operated.

[0063] In summary, the technical solution of this application has the following beneficial effects:

[0064] 1. By adopting the cleaning method of the present invention, according to the water production flow rate of the first-stage reverse osmosis and the second-stage reverse osmosis and the pressure difference of each section, the corresponding reagent is added, the cleaning flow rate is adjusted, and online cleaning is implemented, which can loosen the silicon scale and organic attachments retained by the membrane element and remove them, thereby achieving a good cleaning effect. Compared with the offline cleaning used in the prior art, this application saves more than 400,000 yuan per year.

[0065] 2. After the test summary, in the five years of operation of the boiler feed water treatment equipment, 3 sets of primary reverse osmosis and 2 sets of secondary reverse osmosis were frequently blocked, the output of the primary reverse osmosis dropped to 50 t / h, and the output of the secondary reverse osmosis dropped to 36 t / h. By adopting the cleaning method of the present invention, the output of the primary reverse osmosis was restored to 75 t / h, and the output of the secondary reverse osmosis was restored to 50 t / h, both of which were able to be restored to the designed output. In addition, the application is simple to operate, highly practical and has good effects.

[0066] 3. The equipment of the present invention is based on the advanced technology of reverse osmosis plus mixed bed ion exchange technology, which reuses urban water as boiler water with high quality, overcomes the defect that traditional physical and chemical and biochemical treatment processes cannot recycle urban water as production line water, and solves the problems of excessive organic matter, heavy metal ions, hardness, acid-base neutralization and salt in wastewater that are difficult to solve in existing conventional ultrapure water treatment processes, affecting the water quality of ultrapure water, membrane pollution and equipment operation stability.

[0067] The above are only preferred embodiments of the present invention, and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the description and illustrations of the present invention should be included in the protection scope of the present invention.

Claims

1. A boiler feed water treatment equipment, characterized in that: include: The pretreatment system comprises a clarifier, a variable pore filter, a raw water heater, a raw water tank, a dual-media filter, an ultrafiltration safety filter, an ultrafiltration device, an ultrafiltration water tank and a reverse osmosis safety filter which are sequentially connected via pipelines. A lifting pump is provided on the connecting pipeline between the urban water treatment plant and the clarifier, a raw water pump is provided on the connecting pipeline between the variable pore filter and the raw water heater, a filtration ultrafiltration water pump is provided on the connecting pipeline between the raw water tank and the dual-media filter, and a clean water pump is provided between the ultrafiltration water tank and the reverse osmosis safety filter; A primary reverse osmosis system, using a primary high-pressure pump to introduce the stored water after adsorption treatment by the reverse osmosis security filter for reverse osmosis treatment, the primary osmosis system comprises a primary one-stage membrane assembly and a primary two-stage membrane assembly, the output pipelines of the primary one-stage membrane assembly are respectively connected to the primary fresh water tank and the primary two-stage membrane assembly, and the output pipelines of the primary two-stage membrane assembly are respectively connected to the primary fresh water tank and the high-salinity wastewater tank; A secondary reverse osmosis system, using a secondary high-pressure pump to introduce the water stored in the primary fresh water tank for secondary reverse osmosis treatment, the secondary osmosis system comprises a secondary first-stage membrane assembly and a secondary second-stage membrane assembly, the output pipeline of the secondary first-stage membrane assembly is respectively connected to the secondary fresh water tank and the secondary second-stage membrane assembly, and the output pipeline of the secondary second-stage membrane assembly is respectively connected to the secondary fresh water tank and the ultrafiltration water tank; The desalination system comprises a mixed bed and a desalination water tank which are sequentially connected via pipelines, the water stored in the secondary fresh water tank is pumped into the mixed bed by a fresh water pump, and the desalted water produced by the mixed bed is transported to the desalted water tank; Wherein, the primary reverse osmosis system and the secondary reverse osmosis system are connected with a cleaning device, the liquid outlet of the cleaning device is respectively connected with the cleaning liquid inlet of the primary one-stage membrane assembly, the cleaning liquid inlet of the primary two-stage membrane assembly, the cleaning liquid inlet of the secondary one-stage membrane assembly and the cleaning liquid inlet of the secondary two-stage membrane assembly, the cleaning liquid outlet of the primary one-stage membrane assembly, the cleaning liquid outlet of the primary two-stage membrane assembly, the cleaning liquid outlet of the secondary one-stage membrane assembly and the cleaning liquid outlet of the secondary two-stage membrane assembly all lead to the cleaning device; manual valves are provided on the connecting pipelines of the cleaning device; differential pressure gauges are installed between the inlets and outlets of the primary one-stage membrane assembly, the primary two-stage membrane assembly, the secondary one-stage membrane assembly and the primary two-stage membrane assembly.

2. A boiler feed water treatment equipment according to claim 1, characterized in that: The water production flow rate of the primary reverse osmosis system is 50t / h-75t / h, and the water production flow rate of the secondary reverse osmosis system is 36t / h-50t / h.

3. A boiler feed water treatment equipment according to claim 1, characterized in that: The boiler feed water treatment equipment includes three sets of the primary reverse osmosis systems connected in parallel and two sets of the secondary reverse osmosis systems connected in parallel.

4. A boiler feed water treatment equipment according to claim 1, characterized in that: The first-stage one-stage membrane assembly includes fifteen membrane assemblies, each of which is filled with six membrane elements; the first-stage two-stage membrane assembly includes seven membrane assemblies, each of which is filled with six membrane elements.

5. A boiler feed water treatment equipment according to claim 4, characterized in that: The membrane element and the membrane assembly are detachably mounted, and the shape and specification of the membrane element match the cross-sectional shape of the membrane assembly.

6. The boiler feed water treatment equipment according to claim 1, characterized in that: The two-stage one-stage membrane assembly includes six membrane assemblies, each of which is filled with six membrane elements; the two-stage two-stage membrane assembly includes three membrane assemblies, each of which is filled with six membrane elements.

7. The boiler feed water treatment equipment according to claim 1, characterized in that: The cleaning device comprises a cleaning solution tank and a cleaning filter connected to each other. A cleaning pump is arranged on the output pipeline of the cleaning filter. A heating device and a pH meter are arranged in the cleaning solution tank.

8. A boiler feed water treatment equipment according to claim 7, characterized in that: The cleaning solution tank is filled with cleaning agents, which are formulated according to the types of dirt.

9. A cleaning method for a boiler feed water treatment device according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1. Start: According to the display of the pressure difference meter of the primary reverse osmosis system and the secondary reverse osmosis system, start the cleaning of the corresponding membrane components; S2. Water flushing: Use the deionized water with four times the water output of the corresponding reverse osmosis membrane module segment to circulate and flush the membrane module for 20-30 minutes from the cleaning solution tank to flush away the fluffy attachments on the surface of the membrane element; S3. Alkaline cleaning: add water to the cleaning solution tank to 1.2-1.5 meters, heat to 32-38℃, add alkaline cleaning agent, circulate and flush the membrane module for 2-3 hours, let it stand for 10 hours, circulate and clean again for 1-2 hours, empty the alkaline cleaning solution in the cleaning solution tank, clean up the sludge brought out by the cleaning solution return water, add deionized water and circulate and flush until the cleaning solution return water is neutral; S4. Pickling: Fill the cleaning solution tank with water to 1.2-1.5 meters, configure the acidic cleaning agent in the cleaning solution tank, circulate and flush for 2-3 hours, drain the acidic cleaning solution, add non-oxygen bactericide solution and circulate and flush for 2-3 hours, let it stand for ten hours, and then drain the cleaning solution tank; inject deionized water and circulate and flush until the cleaning solution return water is neutral; S5: Waste liquid treatment: The waste acid liquid and alkali liquid generated by cleaning are introduced into the wastewater pool, neutralized to a pH value of 6-9, and sent to the desulfurization absorption tower.

10. A cleaning method according to claim 9, characterized in that: In step S1, when the pressure difference of each section rises to 120 KPa or the water production flow rate of the corresponding membrane assembly drops to 85% of the rated flow rate, it is judged as fouling and the cleaning device is manually started.

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