Coal gas boiler and condensing steam turbine water treatment system

Abstract

The present application relates to a kind of coal gas boiler and condensing steam turbine water treatment system, make-up water treatment system is used to supply desalted water to boiler;Condensate polishing system is used to treat the condensate formed after the steam generated in the boiler flows into steam turbine;Chemical dosing system is used to add ammonia to treated make-up water and condensate, and add acetone oxime to treated make-up water, and add phosphate to boiler water.The beneficial effect is that: the water quantity provided to 320t / h superhigh temperature subcritical coal gas boiler is 2x60t / h, which can also meet the condensate treatment of 100MW intermediate once-reheated condensing steam turbine, ammonia added to condensate and make-up water can ensure that the metal material of water vapor system is not corroded, acetone oxime added to make-up water can perform chemical deoxygenation treatment on make-up water, and phosphate added to boiler water can prevent calcium and magnesium scale from forming on the tube wall of heating surface of drum boiler, prolonging the chemical cleaning cycle of the boiler.

Description

Technical Field

[0001] This invention relates to the field of water treatment technology for gas boilers and condensing steam turbines, specifically to a water treatment system for gas boilers and condensing steam turbines. Background Technology

[0002] In some production lines that generate large amounts of blast furnace gas, converter gas, and coke oven gas, a significant amount of gas remains after deducting the amount used for process production. This surplus gas can be recycled and reused. Often, this surplus gas is recycled and reused by ultra-high temperature subcritical gas generator sets for power generation, achieving optimal resource allocation, improving resource recycling rates, reducing overall energy consumption and production costs, and increasing the company's economic benefits and market competitiveness. For example, an ultra-high temperature subcritical gas generator set can be constructed using a 320t / h ultra-high temperature subcritical gas boiler + a 100MW intermediate reheat condensing steam turbine + a 100MW generator and supporting auxiliary facilities. The steam parameters of the 320t / h ultra-high temperature subcritical gas boiler are: 17... At 5MPa and 571℃, the boiler feedwater volume is determined based on the following steam-water balance analysis: In-plant steam-water circulation loss is 9.9t / h (3% of the boiler's maximum evaporation), boiler blowdown loss is 1.65t / h (0.5% of the boiler's continuous evaporation), water consumption of existing units is 45t / h (including externally supplied steam), and normal boiler feedwater volume for newly built units is 11.55t / h, totaling 56.55t / h. Therefore, a feedwater treatment system meeting the corresponding operating conditions should be provided. Similarly, after the steam generated by the 320t / h ultra-high temperature subcritical gas boiler enters the 100MW intermediate reheat condensing steam turbine, the condensate volume under VWO conditions is 220m³. 3 / h, condensate flow rate under THA conditions: 197m³ 3 Therefore, a corresponding condensate polishing system should be provided to treat the condensate under the corresponding operating conditions. However, there is currently a lack of a water treatment system that can meet the requirements of a 320t / h ultra-high temperature subcritical gas boiler + 100MW intermediate reheat condensing steam turbine. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a gas boiler and a condensing steam turbine water treatment system to overcome the shortcomings of the prior art.

[0004] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: A gas boiler and a condensing steam turbine water treatment system, comprising:

[0005] Makeup water treatment system, used to supply demineralized water to the boiler;

[0006] A condensate polishing system is used to treat the condensate formed after the steam generated in the boiler flows into the steam turbine.

[0007] A chemical dosing system is used to add ammonia to treated makeup water and condensate, to acetone oxime to treated makeup water, and to add phosphate to boiler water.

[0008] Based on the above technical solution, the present invention can be further improved as follows.

[0009] Furthermore, the makeup water treatment system includes: an automatic heating device, a multi-media filter, a self-cleaning filter, an ultrafiltration device, a first-stage reverse osmosis device, a second-stage reverse osmosis device, an EDI device, and a demineralized water tank, all connected in sequence to the raw water tank; the automatic heating device is used to heat the incoming water to maintain it at 20℃~25℃, and the output of the automatic heating device is 108m³ / h. 3 The automatic heating device requires low-pressure steam with a pressure less than 0.8 MPa and a temperature of 200℃ as the heat medium; the multi-media filter uses graded quartz sand and anthracite as filter media, and is connected to a backwash water pump and compressed air piping for enhanced backwashing; the self-cleaning filter has a filtration accuracy of 100 μm and an output of 108 m³ / h. 3 / h; the output of the ultrafiltration unit is 97m³ / h. 3 / h, operating cycle 30min~60min, backwash time 30s~60s; the output of the first-stage reverse osmosis unit is 74m³ / h. 3 / h, the output of the secondary reverse osmosis unit is 74m³ / h. 3 / h; the output of the EDI device is 60m 3 / h.

[0010] Furthermore, the water supply treatment system also includes: a bactericide dosing device, a reducing agent dosing device, a scale inhibitor dosing device, and an alkali dosing device. The bactericide dosing device is used to add bactericide to the water flowing into the automatic heating device from the raw water tank. The reducing agent dosing device and the scale inhibitor dosing device are used to add reducing agent and scale inhibitor to the water flowing into the first-stage reverse osmosis device from the ultrafiltration device, respectively. The alkali dosing device is used to add alkali to the water flowing into the second-stage reverse osmosis device from the first-stage reverse osmosis device.

[0011] Furthermore, both the primary and secondary reverse osmosis units include: a reverse osmosis security filter, a high-pressure pump, a reverse osmosis unit, and a reverse osmosis product water tank connected in sequence. The reverse osmosis security filter has a filtration accuracy of 5μm. The inlet and outlet of the high-pressure pump are equipped with low-pressure protection switches and high-pressure protection switches, respectively. When the water supply is insufficient, causing the water pressure at the inlet of the high-pressure pump to fall below a certain set value, a signal is automatically sent to stop the high-pressure pump. When the water pressure at the outlet of the high-pressure pump exceeds a certain set value, a signal is automatically sent to automatically cut off the power supply to the high-pressure pump.

[0012] Furthermore, the concentrate produced by the EDI unit is sent into the reverse osmosis permeate tank of the first-stage reverse osmosis unit.

[0013] Furthermore, the makeup water treatment system also includes: a reverse osmosis flushing system and two chemical cleaning systems. The reverse osmosis flushing system uses the reverse osmosis effluent from the first-stage reverse osmosis unit to flush the reverse osmosis membrane of the reverse osmosis unit in the first-stage reverse osmosis unit. The ultrafiltration unit is equipped with a chemical cleaning system. The first-stage reverse osmosis unit, the second-stage reverse osmosis unit, and the EDI unit are all equipped with a chemical cleaning system.

[0014] Furthermore, the acid and alkaline wastewater produced by the primary reverse osmosis unit, the secondary reverse osmosis unit, and the EDI unit is discharged into a collection pit. The acid and alkaline wastewater in the collection pit is then pumped into the wastewater neutralization tank of the condensate polishing system by a corrosion-resistant submersible pump.

[0015] Furthermore, the condensate polishing system includes: a pre-filter, a high-speed mixed bed, and an external regeneration system connected in sequence to the turbine condensate outlet. The acid and alkali wastewater generated by the high-speed mixed bed and the external regeneration system is discharged into the wastewater neutralization tank. The external regeneration system is connected to the acid and alkali storage, metering and supply system. The pre-filter, high-speed mixed bed, external regeneration system and wastewater neutralization tank are respectively connected to the compressed air system.

[0016] Furthermore, the output of the pre-filter is Q = 260 t / h, and it is filled with a backwashable filter element. The inlet and outlet main pipes of the pre-filter are equipped with a bypass with a continuously adjustable opening of 0 to 100%. The output of the high-speed mixed bed is Q = 130 t / h. There are two high-speed mixed beds, and the two high-speed mixed beds are used in parallel. The inlet and outlet main pipes of each high-speed mixed bed are equipped with a bypass with a continuously adjustable opening of 0 to 100%.

[0017] Furthermore, the in vitro regeneration system includes: a resin separation tower, which is connected to a cation resin regeneration and resin storage tank and an anion resin regeneration tank, respectively. The cation resin regeneration and resin storage tank and the anion resin regeneration tank are each equipped with a regeneration flushing water pump, which is connected to the demineralized water tank of the makeup water treatment system; and an acid and alkali storage and metering supply system supplies acid and alkali solutions to the cation resin regeneration and resin storage tank and the anion resin regeneration tank.

[0018] The beneficial effects of this invention are:

[0019] 1) This water treatment system can provide 2×60t / h of water to a 320t / h ultra-high temperature subcritical gas boiler, and can also meet the condensate treatment needs of a 100MW intermediate reheat condensing steam turbine, with high water utilization rate.

[0020] 2) Based on the water chemistry conditions of subcritical units, in order to minimize the corrosive effect of water and prevent the components in the steam-water circulation system from being corroded, according to the boiler feedwater and steam quality requirements specified in GB / T 12145-2016, ammonia is added to the condensate / makeup water. Adding ammonia can increase the pH value of the condensate and makeup water, ensuring that the metal materials in the steam-water system are not corroded, which plays a crucial role in protecting the steam-water system equipment. Adding acetone oxime to the makeup water can chemically deoxygenate the makeup water, and adding phosphate to the boiler water can prevent the formation of calcium and magnesium scale on the heating surface tube wall of the boiler drum and extend the chemical cleaning cycle of the boiler.

[0021] 3) The condensate polishing system can effectively and continuously remove metal corrosion products from the thermal system or salts that enter the system due to minor leaks in the condenser, thereby improving the unit's efficiency and extending the acid washing cycle. When the unit is started, the polishing system can also greatly shorten the unit's start-up time and reduce the large amount of drainage loss during start-up. Attached Figure Description

[0022] Figure 1 This is a structural diagram of the gas boiler and condensing steam turbine water treatment system in this invention;

[0023] Figure 2 This is a structural diagram of the water supply treatment system in this invention;

[0024] Figure 3 This is a structural diagram of the condensate polishing system in this invention;

[0025] Figure 4 This refers to a portion of the piping in the condensate polishing system of this invention. Figure 1 ;

[0026] Figure 5 This refers to a portion of the piping in the condensate polishing system of this invention. Figure 2 ;

[0027] Figure 6 This refers to a portion of the piping in the condensate polishing system of this invention. Figure 3 .

[0028] The attached diagram lists the components represented by each number as follows:

[0029] 1. Makeup Water Treatment System: 101. Raw Water Tank; 102. Automatic Heating Device; 103. Multi-Media Filter; 104. Self-Cleaning Filter; 105. Ultrafiltration Device; 106. First-Stage Reverse Osmosis Device; 107. Second-Stage Reverse Osmosis Device; 108. EDI Device; 109. Demineralized Water Tank; 110. Bactericide Dosing Device; 111. Reducing Agent Dosing Device; 112. Scale Inhibitor Dosing Device; 113. Alkali Dosing Device; 114. Reverse Osmosis Flushing System; 115. Chemical Cleaning System; 2. Condensate Polishing System: 201 1. Pre-filter; 202. High-speed mixed bed; 203. External regeneration system; 2031. Resin separation tower; 2032. Cation resin regeneration and resin storage tank; 2033. Anion resin regeneration tank; 2034. Regeneration flushing water pump; 204. Wastewater neutralization tank; 205. Acid and alkali storage and metering supply system; 206. Compressed air system; 2061. Roots blower; 2062. Air storage tank; 207. Wastewater resin capture device; 208. Electric hot water tank; 209. Backwash water pump; 3. Chemical dosing system; 4. Boiler; 5. Steam turbine. Detailed Implementation

[0030] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0031] Example 1

[0032] like Figures 1-3 As shown, a gas boiler and a condensing steam turbine water treatment system include:

[0033] Makeup water treatment system 1 is used to supply demineralized water to boiler 4;

[0034] The condensate polishing system 2 is used to treat the condensate formed after the steam generated in the boiler 4 flows into the turbine 5. The boiler 4 is a 320t / h ultra-high temperature subcritical gas boiler, and the turbine 5 is a 100MW intermediate once-reheat condensing turbine. The boiler thermal efficiency (Class B) is ≥91.6%, and the unit heat rate (Class B) is ≤7677kJ / kW.h.

[0035] Type of 320t / h ultra-high temperature subcritical gas boiler: ultra-high temperature subcritical, natural circulation, single furnace, balanced draft, single reheat, gas-fired drum boiler; Air preheater: tubular air preheater; Combustion method: opposed combustion on the front and rear walls, low-NOx burner; Ignition method: coke oven gas ignition; Superheated steam: rated evaporation capacity: 320t / h; maximum continuous output: 330t / h; Rated steam pressure (superheater outlet): 17.5MPa.g; Rated steam temperature (superheater outlet): 571℃; Reheat steam flow rate (B-MCR) 266 t / h; Inlet / outlet steam pressure (B-MCR): 3.67 / 3.42 MPa.g; Inlet / outlet steam temperature (B-MCR): 344.5 / 569℃; Feedwater temperature (B-MCR): 275.7℃; Air preheater inlet air temperature: 20℃; Air preheater outlet air temperature: 246℃; Gas heater outlet flue gas temperature: 140℃; Normal boiler blowdown rate: ≤0.5%; Boiler guaranteed thermal efficiency: ≥91.6% (including flue gas-gas heat exchanger, BECR, design fuel, based on lower heating value);

[0036] Type of 100MW intermediate reheat condensing steam turbine: ultra-high temperature subcritical, single-shaft, twin-cylinder single-exhaust, condensing; Nameplate operating power: 100MW (TRL); Heat consumption acceptance operating power: 100MW (THA); Maximum power: 110MW (VWO); Rated speed: 3000r / min; Main steam pressure: 16.70MPa(a); Main steam temperature: 566℃; Reheat steam temperature: 566℃; Exhaust... Steam pressure: 4.9 kPa(a); Main steam flow rate: 279.3 t / h(THA); Reheat steam flow rate: 240.97 t / h(THA); Reheat steam inlet pressure: 3.116 MPa(a)(THA); Reheat steam inlet temperature: 566℃; High-pressure cylinder exhaust pressure: 3.462 MPa(a)(THA); High-pressure cylinder exhaust temperature: 342.6℃(THA); Cooling water design temperature: 20℃ (maximum 33℃);

[0037] Chemical dosing system 3 is used to add ammonia to the treated makeup water and condensate, to add acetone oxime to the treated makeup water, and to add phosphate to the boiler water.

[0038] For makeup water: various non-corrosive fluids are transported using ordinary seamless steel pipes, while acidic and corrosive fluids are transported using rigid polyvinyl chloride (UPVC) pipes and stainless steel pipes. Demineralized water is transported using stainless steel pipes.

[0039] For condensate: Based on the corrosiveness of the medium and the anti-corrosion requirements of the medium for the pipeline, the demineralized water pipeline and resin delivery pipeline of the condensate polishing system 2 are made of stainless steel, the condensate pipeline is made of carbon steel pipe and stainless steel pipe, the regenerated acid pipe is made of steel-lined plastic pipe, and the regenerated alkali pipe is made of stainless steel pipe.

[0040] The makeup water treatment system 1 heats the makeup water and delivers it to the boiler economizer, and provides desuperheating water to the boiler superheated steam desuperheater, reheat steam emergency desuperheater and turbine high-pressure bypass device. The boiler makeup water has three lines: main line (100% BMCR), bypass line (100% BMCR) and water supply bypass line (35% BMCR). When the boiler feedwater capacity is greater than 35% of the capacity, the feedwater flow rate is regulated by frequency conversion or regulating valve.

[0041] The condensate from turbine 5 is drawn out from the condenser hot well through the main pipe, and then split into two paths to two condensate pumps (one in use and one on standby, frequency converter), and then merged into the condensate polishing system 2.

[0042] According to the water chemistry conditions of subcritical units, in order to minimize the corrosive effect of water and prevent the components in the water-steam circulation system from being corroded, ammonia is added to the condensate / makeup water in accordance with the boiler feedwater and steam quality requirements specified in GB / T 12145-2016. Adding ammonia can increase the pH value of the condensate and makeup water, maintain the pH value in the water at a certain level, and ensure that the metal materials in the water-steam system are not corroded. This plays a crucial role in protecting the equipment in the water-steam system.

[0043] A single ammonia dosing system (two tanks and four pumps) is equipped with four dosing pumps, two solution tanks, and two automatic mixers. Two pumps are used for feedwater ammonia dosing, with one pump in operation and one on standby during normal operation. Two pumps are used for condensate ammonia dosing, with one pump in operation and one on standby during normal operation. The ammonia dosing point for makeup water is located on the deaerator outlet pipe, and the ammonia dosing point for condensate is located on the high-speed mixed bed outlet header pipe. Ammonia dosing for both makeup water and condensate is done automatically. The amount of ammonia added to makeup water is adjusted according to the pH signal of the feedwater, and the amount of ammonia added to condensate is adjusted according to the pH signal of the condensate.

[0044] The makeup water chemical deoxygenation treatment uses acetone oxime as a deoxygenating agent, equipped with a set of makeup water acetone oxime dosing devices, including two dosing pumps, one dosing tank, one solution tank, and one automatic mixer. During normal operation, one dosing pump is in operation and the other is on standby. The makeup water acetone oxime dosing point is located on the deaerator outlet pipe. Makeup water acetone oxime is added automatically, and the dosage is automatically adjusted according to the oxygen content signal of the feed water. The purpose of boiler water phosphate treatment is to prevent the formation of calcium and magnesium scale on the heating surface tube wall of the boiler drum and extend the chemical cleaning cycle of the boiler. A phosphate dosing device is configured, equipped with two metering dosing pumps, one dosing tank, one solution tank, and one automatic mixer. During normal operation, one dosing pump is in operation and the other is on standby. The phosphate solution is directly added to the boiler drum through the high-pressure metering pump. Boiler water phosphate dosing is done automatically, and the dosage is automatically adjusted according to the phosphate content signal of the boiler water.

[0045] In this invention, the water source is fresh industrial water, and the backup water source is softened water from the plant area. The quality of the fresh industrial water is as follows:

[0046]

[0047]

[0048] According to GB / T12145-2016 standard, the quality standards for feedwater, boiler water, and steam of the turbine and boiler are as follows:

[0049] 1) Water quality requirements for water supply:

[0050]

[0051] 2) Boiler water quality requirements:

[0052]

[0053]

[0054] 3) Steam quality standards

[0055]

[0056] Example 2

[0057] like Figure 2 As shown, this embodiment is a further optimization based on embodiment 1, as detailed below:

[0058] The normal water supply of the newly built unit boiler is 12t / h, and the maximum water supply when supplying demineralized water / steam is 57t / h. Considering the system's own water consumption and water tank accumulation, the scale of the water treatment system is designed as 2×60t / h. Under normal operation, one is in operation and one is on standby. The increase in water volume during startup or accident is solved by the system's designed output margin and the water storage volume of the demineralized water tank.

[0059] Based on the analysis of the raw water quality and the requirements of the subcritical unit for the quality of the makeup water, the boiler makeup water treatment system 1 is proposed to use a multi-media filter + ultrafiltration (UF) + two-stage reverse osmosis (RO) + EDI process.

[0060] Boiler feedwater treatment system 1 effluent water quality:

[0061]

[0062]

[0063] The boiler feedwater treatment system 1 includes: an automatic heating device 102, a multi-media filter 103, a self-cleaning filter 104, an ultrafiltration device 105, a first-stage reverse osmosis device 106, a second-stage reverse osmosis device 107, an EDI device 108, and a demineralized water tank 109, all connected in sequence to the raw water tank 101. The raw water tank 101, automatic heating device 102, multi-media filter 103, self-cleaning filter 104, ultrafiltration device 105, first-stage reverse osmosis device 106, second-stage reverse osmosis device 107, EDI device 108, and demineralized water tank 109 can be connected by a main pipe.

[0064] Because the permeate flow rate of ultrafiltration and reverse osmosis membranes is greatly affected by changes in the feed water temperature, an automatic heating device 102 is installed to prevent a decrease in permeate flow rate due to low water temperature in winter. This automatic heating device 102 heats the feed water to maintain it at 20℃~25℃, and its output is 108m³ / h. 3 The automatic heating device 102 is equipped with two sets, two units connected in parallel, one for use and one for standby. The heat medium required by the automatic heating device 102 is low-pressure steam with a pressure of less than 0.8 MPa and a temperature of 200℃.

[0065] The multi-media filter 103 uses graded quartz sand and anthracite as filter media, and is connected to a backwash water pump and compressed air piping for enhanced backwashing; the self-cleaning filter 104 has a filtration accuracy of 100μm and an output of 108m³ / h. 3 / h; the output of ultrafiltration unit 105 is 97m³ / h. 3 / h, operating cycle 30min~60min, backwash time 30s~60s; the output of the first-stage reverse osmosis unit 106 is 74m³ / h. 3 / h, the output of the secondary reverse osmosis unit 107 is 74m³ / h. 3 / h; the output of EDI device 108 is 60m 3 / h.

[0066] The filter media of the multi-media filter 103 is graded quartz sand and anthracite. In order to clean the filter media, two filter backwash water pumps are provided and connected to the compressed air piping for enhanced backwashing. The backwash water is the reverse osmosis concentrate from the first-stage reverse osmosis unit 106.

[0067] The output of the self-cleaning filter 104 is 108m. 3 The system has two units per hour, one in operation and one on standby during normal operation. The filtration accuracy is 100μm, mainly removing solid suspended matter, soft impurities and fibrous impurities larger than 100μm from the water, effectively protecting the ultrafiltration membrane. The cleaning process is automatically controlled. When the pressure difference between the inlet and outlet water or the time reaches the set value, the system automatically starts the cleaning process. The water flow continues during the cleaning process, and water can be produced normally.

[0068] The ultrafiltration unit 105 serves as a pretreatment for reverse osmosis, primarily removing suspended solids, colloids, color, turbidity, organic matter, microorganisms, and heavy metals from the raw water—impurities that hinder subsequent reverse osmosis operation. The ultrafiltration backwashing process is fully automated, controlled by the transmembrane pressure difference. Its operating cycle is 30-60 minutes, and the backwashing time is 30-60 seconds. The backwash water is ultrafiltration permeate, and the backwash wastewater is discharged into the plant's drainage network via a ditch. The output of the ultrafiltration unit 105 is 97 m³ / h. 3 The unit has two units per hour (25℃), with a recovery rate of 90% (within three years). During normal operation, one unit is in use and the other is on standby.

[0069] The output of the first-stage reverse osmosis unit 106 is 74m³. 3 / h, the output of the secondary reverse osmosis unit 107 is 74m³ / h. 3 / h,

[0070] The primary reverse osmosis unit 106 and the secondary reverse osmosis unit 107 mainly remove most of the dissolved salts, colloids, organic matter, and microorganisms from the water. Dissolved solids are retained in the concentrate by the reverse osmosis membrane. The primary reverse osmosis unit 106 has a desalination rate of ≥98% within one year and ≥96%~97% within three years, with a recovery rate of ≥75%. The secondary reverse osmosis unit 107 has a desalination rate of ≥90% within three years and a recovery rate of ≥85%. There are two primary reverse osmosis units 106, one in operation and one on standby during normal operation. There are two secondary reverse osmosis units 107, one in operation and one on standby during normal operation.

[0071] The output of EDI device 108 is 60m. 3The function of the EDI unit is to remove residual ions from the secondary reverse osmosis permeate. The EDI process adopts a continuous electro-deionization process. During the electro-deionization process, the feed water flows through the ion exchange resin in the desalination chamber separated by the anion and cation exchange membranes to generate demineralized water. At the same time, the electrode plates at each end of the device drive the water decomposition reaction under the action of an applied voltage, and cause ions to migrate to the selective permeation membrane within the ion exchange resin and be sent to the concentrate chamber. During the electro-deionization process, the exchange interface between the anion and cation exchange resins—water—is polarized under the action of an electric field and electrolyzed into H+ and OH-. The anion and cation exchange resins are electrochemically regenerated at any time, so that the resin is always in a continuous working state. The entire regeneration process does not require acid or alkali. There are two sets of EDI units 108, one for use and one for standby.

[0072] Furthermore, the makeup water treatment system 1 also includes: a bactericide dosing device 110, a reducing agent dosing device 111, a scale inhibitor dosing device 112, and an alkali dosing device 113; the bactericide dosing device 110 is used to add a bactericide to the water flowing into the automatic heating device 102 via the raw water tank 101 to remove organic microorganisms in the raw water; the reducing agent dosing device 111 and the scale inhibitor dosing device 112 are respectively used to add a reducing agent and a scale inhibitor to the water flowing into the first-stage reverse osmosis device 106 via the ultrafiltration device 105. The reducing agent is added to prevent residual chlorine in the feed water from damaging the reverse osmosis membrane, while the scale inhibitor is added to prevent scaling on the concentrate side of the first-stage reverse osmosis; the alkali dosing device 113 is used to add alkali to the water flowing into the second-stage reverse osmosis device 107 via the first-stage reverse osmosis device 106 to remove CO2 from the feed water of the second-stage reverse osmosis.

[0073] Both the primary reverse osmosis unit 106 and the secondary reverse osmosis unit 107 include: a reverse osmosis security filter, a high-pressure pump, a reverse osmosis unit, and a reverse osmosis product water tank connected in sequence. The reverse osmosis security filter is a 5μm security filter, which is used to intercept particles larger than 5μm in the raw water to prevent them from entering the reverse osmosis unit. The high-pressure pump provides sufficient inlet water pressure to the reverse osmosis unit to meet normal operation requirements. Both the inlet and outlet of the high-pressure pump are equipped with low-pressure protection switches and high-pressure protection switches. When the water supply is insufficient to lower the inlet water pressure of the high-pressure pump below a certain set value, a signal will be automatically sent to stop the high-pressure pump, protecting it from idling. If the outlet pressure of the high-pressure pump exceeds a certain set value due to other reasons, the high-pressure pump outlet high-pressure protection will automatically cut off the power supply to the high-pressure pump, protecting the reverse osmosis unit from operating under overpressure. The high-pressure pump uses a variable frequency motor. The reverse osmosis unit uses the characteristics of the reverse osmosis membrane to remove most of the soluble salts, colloids, organic matter, and microorganisms from the water to ensure that the water quality meets the inlet water requirements of subsequent units.

[0074] To improve the system recovery rate and water utilization rate, the secondary reverse osmosis concentrate is sent to the ultrafiltration water tank of the ultrafiltration unit 105 as the primary reverse osmosis feed water of the primary reverse osmosis unit 106. The primary reverse osmosis concentrate of the primary reverse osmosis unit 106 does not enter the circulating water system. After entering the concentrate tank, it overflows into the drainage ditch and is discharged into the plant's production drainage network.

[0075] The inlet, product, and concentrate pipelines of the first-stage reverse osmosis unit 106 and the second-stage reverse osmosis unit 107 are equipped with a series of control valves, monitoring instruments, and programmable operating systems, resulting in a high level of automation.

[0076] To improve water utilization, the concentrate produced by the EDI unit 108 is sent to the reverse osmosis product water tank of the first-stage reverse osmosis unit 106 and used as the feed water for the second-stage reverse osmosis unit.

[0077] When the performance of the ultrafiltration membrane, reverse osmosis membrane, and EDI module deteriorates, their permeate flow decreases, and the transmembrane pressure difference increases to a set value, the ultrafiltration membrane, reverse osmosis membrane, and EDI module are periodically chemically cleaned according to their fouling status to restore their original characteristics. Therefore, the makeup water treatment system 1 also includes a reverse osmosis flushing system 114 and two chemical cleaning systems 115. The reverse osmosis flushing system 114 uses the reverse osmosis effluent from the first-stage reverse osmosis unit 106 to flush the reverse osmosis membrane of the reverse osmosis unit in the first-stage reverse osmosis unit 106. The ultrafiltration unit 105 is equipped with a chemical cleaning system 115, and the first-stage reverse osmosis unit 106, the second-stage reverse osmosis unit 107, and the EDI unit 108 are all equipped with a chemical cleaning system 115.

[0078] The chemical cleaning system 115 equipped with the ultrafiltration unit 105 includes a 5μm security filter, a stainless steel cleaning pump, and a cleaning solution tank. The chemical cleaning system 115 jointly equipped with the first-stage reverse osmosis unit 106, the second-stage reverse osmosis unit 107, and the EDI unit 108 includes a 5μm security filter, a 1μm security filter, a stainless steel cleaning pump, and a cleaning solution tank. It is recommended that one stainless steel cleaning pump be used and one be kept on standby.

[0079] Reverse osmosis flushing system 114: In order to prevent the formation of scale by metastable scaling substances on the concentrate side after the reverse osmosis unit of the first-stage reverse osmosis unit 106 is shut down, the reverse osmosis effluent of the first-stage reverse osmosis unit 106 is used to flush the reverse osmosis membrane of the reverse osmosis unit in the first-stage reverse osmosis unit 106.

[0080] The acid and alkaline wastewater produced by the primary reverse osmosis unit 106, the secondary reverse osmosis unit 107, and the EDI unit 108 is discharged into a collection pit. The acid and alkaline wastewater in the collection pit is then pumped into the wastewater neutralization tank 204 of the condensate polishing system 2 by a corrosion-resistant submersible pump.

[0081] In addition, the boiler feedwater treatment system 1 can also be equipped with a 4m unit outside the water treatment workshop. 3 The process compressed air storage tank supplies air for ultrafiltration backwashing and ultrafiltration membrane integrity testing, and is equipped with a 2m³ / h compressed air tank. 3 The instrument compressed air storage tank supplies air for pneumatic valves.

[0082] The ultrafiltration unit 105 can be automatically started or started with one button based on the liquid level of the front and rear water tanks. During the system backwashing process, the acid, alkali, and bactericide dosing pumps are automatically activated to perform chemically enhanced backwashing. The first-stage reverse osmosis unit 106 can be automatically started or started with one button based on the liquid level of the front and rear water tanks. It can automatically control the dosing pump based on the oxidation-reduction potential index of the influent. After the first-stage reverse osmosis unit 106 is temporarily shut down, the reverse osmosis flushing water pump is automatically activated, and automatic backwashing is performed after shutdown. The second-stage reverse osmosis unit 107 can be automatically started or started with one button based on the liquid level of the front and rear water tanks. It can automatically control the alkali system dosing pump based on the pH index of the influent. The EDI unit 108 can be automatically started or started with one button based on the liquid level of the front and rear water tanks.

[0083] The condensate polishing system 2 can effectively and continuously remove metal corrosion products from the thermal system or salts that enter the system due to minor leaks in the condenser, thereby improving the unit's efficiency and extending the acid washing cycle. When the unit is started up, the polishing system can also greatly shorten the unit's start-up time and reduce the large amount of drainage loss during start-up.

[0084] Example 3

[0085] like Figures 3-6 As shown, this embodiment is a further optimization based on embodiment 1, as detailed below:

[0086] The condensate quality standard, according to GB / T 12145-2016, is as follows:

[0087] 1) Condensate pump outlet water quality

[0088]

[0089] 2) Water quality after desalination of condensate

[0090]

[0091]

[0092] Condensate flow rate of the unit under VWO condition: 220m³ 3 / h, condensate flow rate under THA conditions: 197m³ 3 / h, condensate pump selected with a flow rate of 260m³ / h 3 / h, selected head 265m, closed head ~310m, condensate pump outlet condensate temperature 33℃; condenser heat exchange tube material is TP304 stainless steel.

[0093] Design a full-flow condensate polishing system, employing a pre-filter + high-speed mixed bed treatment process, with a capacity sufficient to handle the maximum condensate volume. The system output is 260 m³ / h. 3 / h, and is equipped with a 100% bypass system. The resin is regenerated in vitro, and the resin separation adopts high-tower separation technology.

[0094] The condensate polishing system 2 includes: a pre-filter 201, a high-speed mixed bed 202, and an external regeneration system 203, which are sequentially connected to the condensate outlet of the steam turbine 5. The acid and alkali wastewater generated by the high-speed mixed bed 202 and the external regeneration system 203 are discharged into the wastewater neutralization tank 204. The external regeneration system 203 is connected to the acid and alkali storage metering and supply system 205. The pre-filter 201, the high-speed mixed bed 202, the external regeneration system 203, and the wastewater neutralization tank 204 are respectively connected to the compressed air system 206.

[0095] Among them, the output of the pre-filter 201 is Q=260t / h, and it is filled with a backwashable filter element. The inlet and outlet water headers of the pre-filter 201 are equipped with a bypass with a continuously adjustable opening of 0 to 100%, and the bypass is equipped with a manual maintenance bypass valve.

[0096] The output of the high-speed mixed bed 202 is Q = 130t / h. The high-speed mixed bed 202 is equipped with a special resin for fine treatment of mixed beds. There are two high-speed mixed beds 202, and the two high-speed mixed beds 202 are used in parallel. Each high-speed mixed bed 202 has a bypass with a continuously adjustable opening of 0 to 100% on the inlet and outlet header pipes. The bypass is equipped with a manual maintenance bypass valve.

[0097] The in vitro regeneration system 203 employs highly efficient resin separation and regeneration technology. After resin failure, it is transported to a resin separation tower, backwashed, and stratified before being transported to cation and anion resin regeneration tanks for regeneration. The in vitro regeneration system 203 is equipped with one DN1500 / DN900 resin separation tower 2031, one DN1000 cation resin regeneration and storage tank 2032, and one DN800 anion resin regeneration tank 2033, and is equipped with two regeneration flushing water pumps 2034. The regeneration flushing water uses demineralized water for resin transport and flushing. The resin separation tower 2031, cation resin regeneration and storage tank 2032, and anion resin regeneration tank 2033 are connected to the wastewater resin capture device 207. The acid and alkali solutions from the acid and alkali storage and metering supply system 205 flow from the high-level storage tank into each metering tank, and are then prepared to the specified concentration by flushing water pumps, acid and alkali injectors, etc., before being sent to the regeneration tanks for resin regeneration. A 4m³ / h acid / alkali solution is also provided. 3The electric hot water tank 208 heats the alkali solution to increase its temperature, thus achieving the best regeneration effect.

[0098] Acid and alkali storage and metering supply system 205: Composed of acid and alkali storage tanks and necessary accessories, it stores HCl and NaOH for resin regeneration. The regeneration acid and alkali are supplied from the market and transported by tank truck to the acid and alkali unloading pump at the acid and alkali warehouse. The acid and alkali are then pumped to a high-level acid and alkali storage tank. This invention has a volume of 5m³. 3 One acid storage tank and one alkali storage tank are provided. The regenerated hydrochloric acid is selected from the first-class or superior quality industrial hydrochloric acid specified in "Industrial Synthetic Hydrochloric Acid (GB320-2006)", using 31% hydrochloric acid and prepared with a concentration of 4% to 8%. The alkali is selected from the first-class quality sodium hydroxide specified in "High Purity Sodium Hydroxide (GB / T 11199-2006)" (HL-II), using 32% sodium hydroxide and prepared with a concentration of 4%.

[0099] The backwash water from the pre-filter 201 and the high-speed mixed bed 202 has good quality and is directly discharged into the ditch. The acid and alkali wastewater generated by the regeneration of the resin in the high-speed mixed bed 202 is discharged into the wastewater neutralization tank 204 through the ditch. Since the acid and alkali equivalents in the discharged wastewater are basically the same, it is only necessary to mix it thoroughly and add a small amount of acid and alkali for adjustment. After the air is introduced for thorough stirring and the pH value is neutralized to 6-9, it is then pumped into the plant's drainage network.

[0100] The condensate polishing system 2 also includes a compressed air system 206, which uses two Roots blowers 2061 for air scrubbing of the resin during resin separation and for stirring in the neutralization tank. A 4m³ / h compressed air blower is also installed. 3 Compressed air storage tank 2062 is used for the process air of the pre-filter 201 for backwashing, mixing, conveying and regeneration of mixed bed resin, and pneumatic valves of the condensate polishing system 2. It is connected to the self-heating engine professional storage tank outlet instrument compressed air pipeline network.

[0101] The operation, backwashing, resin conveying, cleaning, regeneration, forward washing, and mixing of the condensate polishing system 2 are all automatically controlled according to the program. In the initial stage of unit startup, when the iron content of the condensate exceeds 1000μg / L, it does not enter the condensate polishing mixed bed system. Only the pre-filter 201 is put into operation to quickly reduce the iron suspension content in the system. When the pressure difference between the inlet and outlet headers of the pre-filter 201 is greater than 0.1MPa or the iron content of the effluent is abnormal, it indicates that a large amount of solids have been trapped. The pre-filter 201 bypass is opened, the inlet and outlet valves of the pre-filter 201 are closed and it is taken out of operation. Backwashing is performed using the backwash water pump 209 and compressed air.

[0102] The bypass system should automatically open and shut down the filter equipment in condensate polishing system 2 under any of the following conditions:

[0103] ① When the inlet condensate water temperature is ≥55℃;

[0104] ② The filter inlet water pressure is >3.5MPa;

[0105] ③ The pressure difference between the inlet and outlet of the filter is >0.10MPa;

[0106] ④ The iron content in the water discharged from the filter exceeds the standard.

[0107] Two high-speed mixed beds 202 operate simultaneously. When the effluent from one of the mixed beds is unqualified or the pressure difference is too large, the bypass valve opens, and the failed high-speed mixed bed 202 is disconnected. The failed resin is then transported to the external regeneration system 203 for regeneration, and the regenerated spare resin is then transported to the high-speed mixed bed 202.

[0108] The bypass system can automatically open and disconnect the corresponding equipment in the condensate polishing system 2 under any of the following conditions:

[0109] ① The conductivity, silica, or sodium content of the effluent from the mixed bed exceeds the standard;

[0110] ② When the inlet condensate water temperature is ≥55℃;

[0111] ③ The inlet and outlet pressure difference of the fine-treatment mixed bed is >0.35MPa;

[0112] ④ The inlet pressure of the fine treatment system is >3.5MPa.

[0113] Based on the corrosiveness of the medium and the anti-corrosion requirements of the medium for the pipeline, the demineralized water pipeline and resin delivery pipeline of the fine treatment system are made of stainless steel, while the condensate pipeline is made of carbon steel and stainless steel. The regenerated acid pipeline is made of steel-lined plastic pipe, and the regenerated alkali pipeline is made of stainless steel. To prevent outdoor water pipes from freezing in winter, the outdoor pipelines are protected by electric heat tracing and aluminum silicate insulation.

[0114] The construction method for 204 waterproofing in wastewater neutralization tanks is as follows:

[0115] To prevent the pool walls from cracking due to concrete shrinkage, post-pouring strips should be provided along the length of the pool walls during construction, in accordance with the specifications.

[0116] The concrete for the pool wall is poured in layers (before pouring, a 50-100mm thick layer of cement mortar of the same strength grade as the concrete is poured into the bottom of the pool wall), and vibrated in layers. The thickness of the concrete pouring should not exceed 500mm, and the pouring height should not exceed 2m (otherwise, a tremie pipe or other object is used to guide the concrete into the formwork). The vibration points are distributed at a spacing of 100mm-150mm.

[0117] When pouring concrete, the new and old concrete should bond in time and cold joints are not allowed. The old concrete surface should be covered and vibrated with new concrete before the initial setting. When vibrating, the vibrator should be inserted into the old concrete at least 100mm. Otherwise, cold joints or insufficient vibration will appear on the surface of the new and old concrete.

[0118] To effectively prevent concrete cracking, the water-cement ratio of the concrete must be strictly controlled (within 0.45). Dura fibers or Foster fibers can be added to the concrete to enhance its crack resistance.

[0119] After each section of the pool wall is constructed with concrete, burlap sacks are hung on the outside of the pool wall formwork. Water is poured on the concrete when it begins to heat up, and the curing time is about 14 days.

[0120] Before pouring the column concrete, first pour 50mm to 100mm of cement mortar with the same strength grade as the original concrete slurry at the bottom, and then pour the concrete. The thickness of the concrete pour should not exceed 500mm and the pouring height should not exceed 2m. Beams are poured in layers at an angle, advancing at an angle in one direction. Slabs are poured in one direction. During pouring, the concrete is vibrated to ensure compaction.

[0121] The inner wall of the pool is protected against corrosion according to the design requirements. When using paint for corrosion protection, if the surface is uneven, it can be filled with special putty. After the putty dries completely, it is sanded. After the treatment is completed, paint is applied. When applying paint, it should be applied in a crisscross pattern, and each layer should be applied back and forth. The paint should be applied evenly and without any omissions.

[0122] The designed wastewater neutralization tank is made of 204 stainless steel, which has good crack resistance, good resistance to acid and alkali corrosion, and a long service life.

[0123] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A gas boiler and a condensing steam turbine water treatment system, characterized in that, include: Makeup water treatment system (1) is used to supply demineralized water to boiler (4); A condensate polishing system (2) is used to treat the condensate formed after the steam generated in the boiler (4) flows into the turbine (5). The condensate polishing system (2) includes: a pre-filter (201), a high-speed mixed bed (202), and an external regeneration system (203) connected in sequence to the condensate outlet of the turbine (5). The acid and alkali wastewater generated by the high-speed mixed bed (202) and the external regeneration system (203) is discharged into a wastewater neutralization tank (204). The external regeneration system (203) is connected to an acid and alkali storage and metering supply system (205). The pre-filter (201), the high-speed mixed bed (202), the external regeneration system (203), and the wastewater neutralization tank (204) are all connected to the turbine (5). The pre-filter (201) is connected to the compressed air system (206) respectively; the inlet and outlet water headers of the pre-filter (201) are provided with a bypass with a continuously adjustable opening of 0 to 100%, and the bypass is provided with a manual maintenance bypass valve; the number of high-speed mixed beds (202) is two, and the two high-speed mixed beds (202) are used in parallel. The inlet and outlet headers of each high-speed mixed bed (202) are provided with a bypass with a continuously adjustable opening of 0 to 100%, and the bypass is provided with a manual maintenance bypass valve; the condensate polishing system (2) also includes: a compressed air system (206), which is used for air scrubbing of resin during resin separation and for stirring of wastewater neutralization tank, and for backwashing of pre-filter (201), mixing of mixed bed resin, conveying and regeneration unit process air; In the initial stage of unit startup, when the iron content of condensate exceeds 1000 μg / L, the high-speed mixed bed (202) of the condensate polishing system (2) is not used. Only the pre-filter (201) is put into operation to quickly reduce the iron suspension content in the system. When the pressure difference between the inlet and outlet main pipes of the pre-filter (201) is greater than 0.1 MPa or the iron content of the effluent is abnormal, the bypass of the pre-filter (201) is opened, the inlet and outlet valves of the pre-filter (201) are closed and the operation is stopped. Backwashing is performed using the backwash pump (209) and compressed air. The bypass system should automatically open and disconnect the pre-filter in the condensate polishing system (2) under any of the following conditions: ① When the inlet condensate temperature is ≥55℃; ② When the inlet pressure of the pre-filter is >3.5MPa; ③ When the pressure difference between the inlet and outlet of the pre-filter is >0.10MPa; ④ When the iron content in the effluent from the pre-filter exceeds the standard. Two high-speed mixed beds (202) operate simultaneously. When the effluent from one of the mixed beds is unqualified or the pressure difference is too large, the bypass valve is opened, and the failed high-speed mixed bed (202) is disconnected. The failed resin is then transported to the external regeneration system (203) for regeneration. The regenerated spare resin is then transported to the high-speed mixed bed (202). The bypass system will automatically open and disconnect the corresponding equipment in the condensate polishing system (2) under any of the following circumstances: ① The conductivity, silica or sodium content of the mixed bed effluent exceeds the standard; ② The inlet condensate temperature is ≥55℃; ③ The inlet and outlet pressure difference of the polishing mixed bed is >0.35MPa; ④ The inlet pressure of the polishing system is >3.5MPa. The chemical dosing system (3) is used to add ammonia to the treated makeup water and condensate, to add acetone oxime to the treated makeup water, and to add phosphate to the boiler water in the boiler drum. The makeup water ammonia dosing point is located on the deaerator outlet pipe, the condensate ammonia dosing point is located on the high-speed mixed bed outlet header pipe, and the makeup water acetone oxime dosing point is located on the deaerator outlet pipe.

2. The gas boiler and condensing steam turbine water treatment system according to claim 1, characterized in that, The makeup water treatment system (1) includes: an automatic heating device (102), a multi-media filter (103), a self-cleaning filter (104), an ultrafiltration device (105), a first-stage reverse osmosis device (106), a second-stage reverse osmosis device (107), an EDI device (108), and a demineralized water tank (109), all connected in sequence to the raw water tank (101); the automatic heating device (102) is used to heat the incoming water to maintain it at 20℃~25℃, and the output of the automatic heating device (102) is 108m³. 3 / h, the automatic heating device (102) requires low-pressure steam with a pressure of less than 0.8MPa and a temperature of 200℃ as the heat medium; the multi-media filter (103) uses graded quartz sand and anthracite as the filter media, and is connected to a backwash water pump and compressed air piping for enhanced backwashing; the self-cleaning filter (104) has a filtration accuracy of 100μm and an output of 108m 3 / h; the output of the ultrafiltration device (105) is 97m. 3 / h, operating cycle 30min~60min, backwash time 30s~60s; the output of the first-stage reverse osmosis unit (106) is 74m³ / h. 3 / h, the output of the secondary reverse osmosis unit (107) is 74m³ / h. 3 / h; the output of the EDI device (108) is 60m 3 / h.

3. The gas boiler and condensing steam turbine water treatment system according to claim 2, characterized in that, The water supply treatment system (1) further includes: a bactericide dosing device (110), a reducing agent dosing device (111), a scale inhibitor dosing device (112), and an alkali dosing device (113). The bactericide dosing device (110) is used to add bactericide to the water flowing into the automatic heating device (102) via the raw water tank (101). The reducing agent dosing device (111) and the scale inhibitor dosing device (112) are used to add reducing agent and scale inhibitor to the water flowing into the first-stage reverse osmosis device (106) via the ultrafiltration device (105), respectively. The alkali dosing device (113) is used to add alkali to the water flowing into the second-stage reverse osmosis device (107) via the first-stage reverse osmosis device (106).

4. The gas boiler and condensing steam turbine water treatment system according to claim 2, characterized in that, Both the primary reverse osmosis unit (106) and the secondary reverse osmosis unit (107) include: a reverse osmosis security filter, a high-pressure pump, a reverse osmosis unit, and a reverse osmosis product water tank connected in sequence. The reverse osmosis security filter has a filtration accuracy of 5μm. The inlet and outlet of the high-pressure pump are respectively equipped with a low-pressure protection switch and a high-pressure protection switch. When the water supply is insufficient, causing the water pressure at the inlet of the high-pressure pump to be lower than a certain set value, a signal is automatically sent to stop the high-pressure pump. When the water pressure at the outlet of the high-pressure pump exceeds a certain set value, a signal is automatically sent to automatically cut off the power supply to the high-pressure pump.

5. A gas boiler and condensing steam turbine water treatment system according to claim 2, characterized in that, The concentrated water produced by the EDI device (108) is sent into the reverse osmosis permeate tank of the first-stage reverse osmosis device (106).

6. The gas boiler and condensing steam turbine water treatment system according to claim 2, characterized in that, The makeup water treatment system (1) further includes: a reverse osmosis flushing system (114) and two chemical cleaning systems (115). The reverse osmosis flushing system (114) uses the reverse osmosis effluent from the first-stage reverse osmosis unit (106) to flush the reverse osmosis membrane of the reverse osmosis unit in the first-stage reverse osmosis unit (106). The ultrafiltration unit (105) is equipped with a chemical cleaning system (115). The first-stage reverse osmosis unit (106), the second-stage reverse osmosis unit (107) and the EDI unit (108) are jointly equipped with a chemical cleaning system (115).

7. The gas boiler and condensing steam turbine water treatment system according to claim 2, characterized in that, The acid and alkali wastewater produced by the primary reverse osmosis unit (106), the secondary reverse osmosis unit (107) and the EDI unit (108) is discharged into the collection pit. The acid and alkali wastewater in the collection pit is pumped into the wastewater neutralization tank (204) of the condensate polishing system (2) by a corrosion-resistant submersible pump.

8. The gas boiler and condensing steam turbine water treatment system according to claim 1, characterized in that, The output of the pre-filter (201) is 260t / h, and it is filled with a backwashable filter element. The output of the high-speed mixed bed (202) is 130t / h.

9. A gas boiler and condensing steam turbine water treatment system according to any one of claims 1 to 8, characterized in that, The in vitro regeneration system (203) includes: a resin separation tower (2031), which is connected to a cation resin regeneration and resin storage tank (2032) and an anion resin regeneration tank (2033), respectively. The cation resin regeneration and resin storage tank (2032) and the anion resin regeneration tank (2033) are each equipped with a regeneration flushing water pump (2034), which is connected to the demineralized water tank (109) of the makeup water treatment system (1); the acid and alkali storage metering supply system (205) supplies acid and alkali solutions to the cation resin regeneration and resin storage tank (2032) and the anion resin regeneration tank (2033).

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