Gas boiler and condensing steam turbine chemical water system

Abstract

The invention relates to a gas boiler and a condensing steam turbine chemical water system. A make-up water treatment system is used for making up desalted water to the boiler; the condensed water fine processing system is used for processing condensed water formed after steam generated in the boiler flows into the steam turbine; and the chemical dosing system is used for adding ammonia into the treated make-up water and condensed water, adding acetoxime into the treated make-up water and adding phosphate into boiler water. The device has the beneficial effects that the water quantity provided for a 320t / h superhigh-temperature subcritical gas boiler is 2 * 60t / h, the requirements on condensed water treatment and ammonia addition of condensed water and make-up water of a 100MW intermediate primary reheat condensing steam turbine can be met, metal materials of a water vapor system can be prevented from being corroded, the make-up water can be subjected to chemical deoxidization treatment by adding acetoxime into the make-up water, and the water quality is improved. Phosphate is added into boiler water, calcium and magnesium scale can be prevented from being generated on the tube wall of the heating surface of the drum boiler, and the chemical cleaning period of the boiler is prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of water treatment for gas boilers and condensing steam turbines, and in particular to a water treatment system for gas boilers and condensing steam turbines. Background Art

[0002] In some production lines that produce a large amount of blast furnace gas, converter gas and coke oven gas, there is still a large amount of surplus gas that can be recycled after deducting the gas used for process production. The surplus gas is often recycled by ultra-high temperature subcritical gas generator sets for power generation, which can achieve optimal resource allocation, improve resource recycling rate, reduce comprehensive energy consumption and production costs, and increase the economic benefits and market competitiveness of enterprises. For example, a set of 320t / h ultra-high temperature subcritical gas boiler + 100MW intermediate reheat condensing steam turbine + 100MW generator and supporting auxiliary facilities to construct an ultra-high temperature subcritical gas generator set. Since the steam parameters of the 320t / h ultra-high temperature subcritical gas boiler are: 17. 5MPa, 571℃, boiler feed water volume is determined by the following water vapor balance analysis: the water loss of steam-water circulation in the plant is 9.9t / h (3% of the maximum evaporation of the boiler), the water loss of boiler blowdown is 1.65t / h (0.5% of the continuous evaporation of the boiler), the water consumption of the reused unit is 45t / h (including external steam supply), and the normal feed water volume of the boiler of the new unit is 11.55t / h, so the total water volume is 56.55t / h, so it should be equipped with a feed water treatment system that meets the corresponding working conditions. Similarly, after the steam generated by the 320t / h ultra-high temperature subcritical gas boiler enters the 100MW intermediate primary reheat condensing steam turbine, the condensate volume of the unit under VWO working conditions is 220m 3 / h, condensate volume under THA condition 197m 3 / h, so the corresponding condensate polishing system should also be equipped to treat the condensate under the corresponding working conditions. However, there is currently a lack of water treatment systems that can meet the requirements of 320t / h ultra-high temperature subcritical gas boiler + 100MW intermediate single 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 system to overcome the deficiencies in the above-mentioned prior art.

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

[0005] Make-up water treatment system, used to supply demineralized water to the boiler;

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

[0007] Chemical dosing system for adding ammonia to treated feed water and condensate, acetone oxime to treated feed water, and phosphate to boiler water.

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

[0009] Furthermore, the feed water treatment system includes: an automatic heating device, a multi-media filter, a self-cleaning filter, an ultrafiltration device, a primary reverse osmosis device, a secondary reverse osmosis device, an EDI device and a demineralized water tank which are sequentially connected 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 108m 3 / h, the heat medium required by the automatic heating device is low-pressure steam with a pressure of less than 0.8Mpa and a temperature of 200℃; the filter material of the multi-media filter is graded quartz sand and anthracite, and is connected to the backwash water pump and the compressed air piping for enhanced backwashing; the filtration accuracy of the self-cleaning filter is 100μm, and its output is 108m 3 / h; the output of the ultrafiltration device is 97m 3 / h, operation cycle 30min~60min, backwash time 30s~60s; the output of the first-stage reverse osmosis device is 74m 3 / h, the output of the secondary reverse osmosis device is 74m 3 / h; the output of the EDI device is 60m 3 / h.

[0010] Furthermore, the feed water 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 through the raw water tank, the reducing agent dosing device and the scale inhibitor dosing device are used to add reducing agent and scale inhibitor respectively to the water flowing into the primary reverse osmosis device through the ultrafiltration device; the alkali dosing device is used to add alkali to the water flowing into the secondary reverse osmosis device through the primary reverse osmosis device.

[0011] Furthermore, the primary reverse osmosis device and the secondary reverse osmosis device both include: a reverse osmosis safety filter, a high-pressure pump, a reverse osmosis unit and a reverse osmosis water production tank connected in sequence, the filtration accuracy of the reverse osmosis safety filter is 5μm; the inlet and outlet of the high-pressure pump are respectively provided with a low-pressure protection switch and a high-pressure protection switch. When the water supply is insufficient, so that the water pressure at the inlet of the high-pressure pump is 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.

[0012] Furthermore, the concentrated water produced by the EDI device is sent to the reverse osmosis water production tank of the primary reverse osmosis device.

[0013] Furthermore, the feed 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 of the first-stage reverse osmosis device to flush the reverse osmosis membrane of the reverse osmosis unit in the first-stage reverse osmosis device. The ultrafiltration device is equipped with a chemical cleaning system. The first-stage reverse osmosis device, the second-stage reverse osmosis device and the EDI device are jointly equipped with a chemical cleaning system.

[0014] Furthermore, the acid and alkaline wastewater produced by the primary reverse osmosis device, the secondary reverse osmosis device and the EDI device are discharged into the sump, and the acid and alkaline wastewater in the sump is pumped into the wastewater neutralization tank of the condensate polishing system through a corrosion-resistant submersible pump.

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

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

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

[0018] The beneficial effects of the present invention are:

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

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

[0021] 3) The condensate polishing system can effectively and continuously remove the metal corrosion products of the thermal system or the salt that enters the system due to trace leakage of the condenser, thereby improving the efficiency of the unit and extending the pickling cycle. When the unit is started, the polishing system can also greatly shorten the start-up time of the unit and reduce the large amount of drainage losses during startup. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0023] Figure 2 It is a structural diagram of the feed water treatment system in the present invention;

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

[0025] Figure 4 Part of the pipeline of the condensate polishing system in the present invention Figure 1 ;

[0026] Figure 5 Part of the pipeline of the condensate polishing system in the present invention Figure 2 ;

[0027] Figure 6 Part of the pipeline of the condensate polishing system in the present invention Figure 3 .

[0028] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0029] 1. Make-up water treatment system, 101. Raw water tank, 102. Automatic heating device, 103. Multi-media filter, 104. Self-cleaning filter, 105. Ultrafiltration device, 106. Primary reverse osmosis device, 107. Secondary reverse osmosis device, 108. EDI device, 109. Demineralized water tank, 110. Bactericide dosing device, 111. Reductant dosing device, 112. Antiscalant dosing device, 113. Alkali dosing device, 114. Reverse osmosis flushing system, 115. Chemical cleaning system, 2. Condensate polishing system, 201 , pre-filter, 202, high-speed mixed bed, 203, in vitro 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 catcher, 208, electric water tank, 209, backwash water pump, 3, chemical dosing system, 4, boiler, 5, steam turbine. DETAILED DESCRIPTION

[0030] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0031] Example 1

[0032] like Figure 1 to Figure 3 As shown, a gas boiler and condensing steam turbine water system, comprising:

[0033] A feed water treatment system 1 for supplying demineralized water to a 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 steam turbine 5. The boiler 4 is a 320t / h ultra-high temperature subcritical gas boiler, and the steam turbine 5 is a 100MW intermediate single reheat condensing steam turbine; the boiler thermal efficiency (class B) is ≥91.6%, and the unit heat consumption 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 ventilation, single reheat, gas drum boiler; air preheater: tubular air preheater; combustion mode: front and rear wall counter combustion, low nitrogen burner; ignition mode: 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 (B-MCR) :266t / h;Inlet / outlet steam pressure (B-MCR): 3.67 / 3.42MPa.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℃;Boiler normal blowdown rate: ≤0.5%;Boiler guaranteed thermal efficiency: ≥91.6% (including flue gas-gas heat exchanger, BECR, design fuel, based on low calorific value);

[0036] The type of 100MW intermediate single reheat condensing steam turbine is: ultra-high temperature subcritical, single intermediate reheat, single shaft, double cylinder single exhaust, condensing; nameplate working power: 100MW (TRL); heat consumption acceptance working 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: 4.9kPa(a); main steam flow: 279.3t / h(THA); reheat steam flow: 240.97t / h(THA); reheat steam inlet pressure: 3.116MPa(a)(THA); reheat steam inlet temperature: 566℃; high-pressure cylinder exhaust pressure: 3.462MPa(a)(THA); high-pressure cylinder exhaust temperature: 342.6℃(THA); cooling water design temperature: 20℃(maximum 33℃);

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

[0038] For make-up water: various non-corrosive fluids are transported by ordinary seamless steel pipes, acidic and corrosive fluids are transported by rigid polyvinyl chloride (UPVC) pipes and stainless steel pipes, and desalted water is transported by stainless steel pipes;

[0039] For condensate water: According to the corrosiveness of the medium and the anti-corrosion requirements of the medium for the pipeline, the desalted 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 feed water treatment system 1 heats the feed water and transports it to the boiler economizer, and provides cooling water to the boiler superheated steam desuperheater, reheated steam emergency desuperheater and steam turbine high-pressure bypass device. The boiler feed water is provided with three routes: the main route (100% BMCR), the bypass (100% BMCR) and the upper water bypass (35% BMCR). When the boiler feed water capacity is greater than 35% of the capacity, the feed water flow is regulated by frequency conversion or regulating valve.

[0041] The condensate of steam turbine 5 is led out from the condenser hot well through the main pipe, and then divided into two routes to two condensate pumps (one for use and one for standby, frequency conversion regulation), and then merged into the condensate polishing system 2.

[0042] According to the water chemical conditions of the subcritical unit, 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 / feed water according to the boiler feed water and steam quality requirements specified in GB / T 12145-2016. Adding ammonia can increase the pH value of condensate and feed water, maintain the pH value of the water to a certain value, ensure that the metal materials of the water-steam system are not corroded, and play a pivotal role in protecting the water-steam system equipment;

[0043] One set of ammonia dosing device (two tanks and four pumps) is equipped with four dosing pumps, two solution tanks and two automatic mixers, including two feed water ammonia dosing pumps, one for operation and one for standby during normal operation, and two condensate water ammonia dosing pumps, one for operation and one for standby during normal operation. The feed water ammonia dosing point is set on the deaerator outlet pipe, and the condensate water ammonia dosing point is set on the high-speed mixed bed outlet mother pipe. The feed water and condensate water are dosed with ammonia automatically, and the amount of ammonia added to the feed water is adjusted according to the pH signal of the feed water, and the amount of ammonia added to the condensate water is adjusted according to the pH signal of the condensate water;

[0044] Acetone oxime deoxidizer is used for chemical deoxygenation treatment of feed water. A set of acetone oxime dosing device is equipped with two dosing pumps, one dosing box, one solution tank and one automatic mixer. During normal operation, one dosing pump is in operation and one is on standby. The dosing point of acetone oxime for feed water is set on the outlet pipe of the deaerator. Automatic dosing is adopted for acetone oxime for feed water, and the dosing amount is automatically adjusted according to the oxygen content signal of feed water. The purpose of adding phosphate to boiler water is to prevent the formation of calcium and magnesium scale on the heating surface tube wall of drum boiler and extend the chemical cleaning cycle of boiler. A set of phosphate dosing device is equipped with two metering dosing pumps, one dosing box, one solution tank and one automatic mixer. During normal operation, one dosing pump is in operation and one is on standby. Phosphate solution is directly added to the boiler drum through high-pressure metering pump. Automatic dosing is adopted for phosphate addition to boiler water, and the dosing amount is automatically adjusted according to the phosphate content signal of boiler water.

[0045] The water source in the present invention is industrial fresh water, and the backup water source is softened water in the factory. The quality of industrial fresh water is as follows:

[0046]

[0047]

[0048] According to GB / T12145-2016 standard, the quality standards for feed water, boiler water and steam of machines and boilers are:

[0049] 1) Water quality requirements:

[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, and the details are as follows:

[0058] The normal water replenishment volume of the boiler of the newly built unit is 12t / h, and the maximum water supply volume when supplying desalted 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 to be 2×60t / h, with one in operation and one in standby during normal operation. The increase in water volume during startup or accidents is solved by the system design output margin and the water storage volume of the desalted water tank;

[0059] According to the analysis of raw water quality and the requirements of subcritical units for feed water quality, the boiler feed water treatment system 1 is planned to use multi-media filter + ultrafiltration (UF) + two-stage reverse osmosis (RO) + EDI process;

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

[0061]

[0062]

[0063] The boiler feed 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 primary reverse osmosis device 106, a secondary reverse osmosis device 107, an EDI device 108 and a desalted water tank 109, which are sequentially connected to a raw water tank 101. The raw water tank 101, the automatic heating device 102, the multi-media filter 103, the self-cleaning filter 104, the ultrafiltration device 105, the primary reverse osmosis device 106, the secondary reverse osmosis device 107, the EDI device 108 and the desalted water tank 109 can be connected by a mother pipe.

[0064] Since the water permeability of ultrafiltration and reverse osmosis membranes is greatly affected by the change of inlet water temperature, in order to avoid the situation that the water output of ultrafiltration and reverse osmosis membranes decreases due to low water temperature in winter, an automatic heating device 102 is equipped. The automatic heating device 102 is used to heat the inlet water to maintain it at 20℃~25℃. The output of the automatic heating device 102 is 108m 3 / h, the automatic heating device 102 is equipped with two sets, two sets are connected in parallel, one is used and the other is reserved. The heat medium required by the automatic heating device 102 is low-pressure steam with a pressure less than 0.8Mpa and a temperature of 200℃.

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

[0066] The filter media of the multi-media filter 103 are 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 uses the reverse osmosis concentrated water of the first-stage reverse osmosis device 106.

[0067] The output of the self-cleaning filter 104 is 108m 3 / h, there are two units, one for use and one for standby during normal operation, with a filtration accuracy of 100μm. It mainly removes solid suspended matter, soft impurities and fibrous impurities larger than 100μm in the water, effectively protecting the ultrafiltration membrane. The cleaning process is automatically controlled. When the inlet and outlet water pressure difference or time reaches the set value, the system automatically starts the cleaning process. During the cleaning period, the water flows continuously and water can be produced normally.

[0068] The ultrafiltration device 105 is used as a pre-treatment for reverse osmosis. Its main purpose is to remove impurities such as suspended matter, colloid, chromaticity, turbidity, organic matter, microorganisms and heavy metals in the raw water that hinder the subsequent reverse osmosis operation. The ultrafiltration backwash process adopts full automatic control, and the backwash is controlled by the ultrafiltration transmembrane pressure difference. Its operation cycle is 30min~60min, and the backwash time is 30s~60s. The backwash water uses ultrafiltration water, and the backwash drainage is discharged to the factory drainage network through the ditch. The output of the ultrafiltration device 105 is 97m 3 / h (25℃), there are two units, with a recovery rate of 90% (within three years), one for use and one for backup during normal operation.

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

[0070] The primary reverse osmosis device 106 and the secondary reverse osmosis device 107 mainly remove most of the dissolved salts, colloids, organic matter and microorganisms in the water, and the dissolved solids are retained in the concentrated water by the reverse osmosis membrane. The primary reverse osmosis device 106 has a desalination rate of ≥98% within one year, a desalination rate of ≥96%~97% within three years, and a recovery rate of ≥75%. The secondary reverse osmosis device 107 has a desalination rate of ≥90% within three years, and a recovery rate of ≥85%. There are two primary reverse osmosis devices 106, one for use and one for backup during normal operation; there are two secondary reverse osmosis devices 107, one for use and one for backup during normal operation.

[0071] The output of EDI device 108 is 60m 3 / h, its function is to remove the residual ions in the secondary reverse osmosis water. The EDI process adopts a continuous electrodeionization process. During the electrodeionization process, the incoming water flows through the ion exchange resin in the fresh water chamber separated by the anion and cation exchange membrane to generate demineralized water. At the same time, the electrode plates at each end of the device drive the decomposition reaction of water under the action of an external voltage, and make the ions migrate to the selective permeable membrane in the ion exchange resin and be sent to the concentrated water chamber. During the electrodeionization process, the exchange interface of the anion and cation exchange resins - water is polarized and electrolyzed into H+ and OH- under the action of the electric field. The anion and cation exchange resins can be electrochemically regenerated at any time to keep the resin in a continuous working state. The entire regeneration process does not require acid or alkali. The number of EDI devices 108 is two sets, one for use and one for backup.

[0072] Furthermore, the feed 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 through 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 primary reverse osmosis device 106 through the ultrafiltration device 105, the reducing agent is added to prevent the residual chlorine in the influent water from damaging the reverse osmosis membrane, and the scale inhibitor is added to prevent scaling on the concentrated water side of the primary reverse osmosis; the alkali dosing device 113 is used to add alkali to the water flowing into the secondary reverse osmosis device 107 through the primary reverse osmosis device 106, and the alkali is added to remove CO2 in the secondary reverse osmosis influent water.

[0073] The primary reverse osmosis device 106 and the secondary reverse osmosis device 107 both include: a reverse osmosis security filter, a high-pressure pump, a reverse osmosis unit and a reverse osmosis water production tank connected in sequence; the reverse osmosis security filter adopts a 5μm security filter, and its function is to intercept particles larger than 5μm in the raw water to prevent them from entering the reverse osmosis unit; the high-pressure pump: its function is to provide sufficient water inlet pressure for the reverse osmosis unit to meet the normal operation requirements, and the inlet and outlet of the high-pressure pump are equipped with a low-pressure protection switch and a high-pressure protection switch. When the water supply is insufficient to make the water pressure at the inlet of the high-pressure pump lower than a certain set value, a signal will automatically be sent to stop the high-pressure pump to protect the high-pressure pump from working in an idling state. When the outlet pressure of the high-pressure pump exceeds a certain set value due to other reasons, the high-pressure protection at the outlet of the high-pressure pump will automatically cut off the power supply of the high-pressure pump to protect the reverse osmosis unit from operating under overpressure. The high-pressure pump adopts a variable frequency motor; the reverse osmosis unit: the characteristics of the reverse osmosis membrane are used to remove most of the soluble salts, colloids, organic matter and microorganisms in the water to ensure that the water quality meets the water inlet requirements of the subsequent devices.

[0074] In order 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 device 105 to serve as the primary reverse osmosis water inlet of the primary reverse osmosis device 106. The primary reverse osmosis concentrate of the primary reverse osmosis device 106 does not enter the circulating water system, but enters the concentrate tank and is discharged into the drainage ditch through overflow to the production drainage network of the factory area.

[0075] The water inlet, water production and concentrated water pipelines of the primary reverse osmosis device 106 and the secondary reverse osmosis device 107 are equipped with a series of control valves, monitoring instruments and program-controlled operating systems, and the automation level is relatively high.

[0076] In order to improve the utilization rate of water, the concentrated water produced by the EDI device 108 is sent to the reverse osmosis water production tank of the first-stage reverse osmosis device 106 and serves as the second-stage reverse osmosis water.

[0077] When the performance of the ultrafiltration membrane, reverse osmosis membrane and EDI module declines, the water production decreases, and the transmembrane pressure difference increases to the set value, the ultrafiltration membrane, reverse osmosis membrane and EDI module are rationally chemically cleaned from time to time according to the pollution of the operation of the ultrafiltration membrane, reverse osmosis membrane and EDI module to restore their original characteristics. Therefore, the feed 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 of the first-stage reverse osmosis device 106 to flush the reverse osmosis membrane of the reverse osmosis unit in the first-stage reverse osmosis device 106. The ultrafiltration device 105 is equipped with a chemical cleaning system 115, and the first-stage reverse osmosis device 106, the second-stage reverse osmosis device 107 and the EDI device 108 are jointly equipped with a chemical cleaning system 115.

[0078] The chemical cleaning system 115 equipped with the ultrafiltration device 105 includes: a 5μm safety filter, a stainless steel cleaning pump and a cleaning solution tank, and the chemical cleaning system 115 commonly equipped with the first-stage reverse osmosis device 106, the second-stage reverse osmosis device 107 and the EDI device 108 includes: a 5μm safety filter, a 1μm safety filter, a stainless steel cleaning pump and a cleaning solution tank. It is recommended to use one stainless steel cleaning pump and keep one as a backup.

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

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

[0081] In addition, the boiler feed water treatment system 1 can also be equipped with a 4m 3 The compressed air storage tank is used for ultrafiltration backwashing and ultrafiltration membrane integrity testing. A 2m 3 Instrument compressed air storage tank to supply air to pneumatic valves.

[0082] The ultrafiltration device 105 can be automatically started or started with one button according to the liquid level control of the front and rear water tanks. During the system backwashing process, the acid, alkali and bactericide dosing pumps are automatically put into operation for chemical enhanced backwashing; the first-level reverse osmosis device 106 can be automatically started or started with one button according to the liquid level control of the front and rear water tanks. The dosing pump can be automatically controlled to be put into operation according to the redox potential index of the influent water. After the first-level reverse osmosis device 106 is temporarily shut down, the reverse osmosis flushing water pump is automatically put into operation, and backwashing is automatically performed after the shutdown; the second-level reverse osmosis device 107 can be automatically started or started with one button according to the liquid level control of the front and rear water tanks. The dosing pump of the alkali system can be automatically controlled to be put into operation according to the pH index of the influent water. The EDI device 108 can be automatically started or started with one button according to the liquid level control 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 salt that enters the system due to trace leakage of the condenser, thereby improving the efficiency of the unit and extending the pickling cycle. When the unit is started, the polishing system can also greatly shorten the start-up time of the unit and reduce a large amount of drainage losses during startup.

[0084] Example 3

[0085] like Figure 3 to Figure 6 As shown, this embodiment is a further optimization based on Embodiment 1, and the details are as follows:

[0086] Condensate quality standard, according to GB / T 12145-2016 standard, the selected condensate quality standard is:

[0087] 1) Condensate pump outlet water quality

[0088]

[0089] 2) Water quality after condensate desalination

[0090]

[0091]

[0092] The condensate volume of the unit under VWO condition is 220m 3 / h, condensate volume under THA condition 197m 3 / h, condensate pump selection flow rate 260m 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, using pre-filter + high-speed mixed bed treatment process, its capacity meets the maximum condensate treatment requirements, system output 260m 3 / h, and is equipped with a 100% bypass system. The resin is regenerated in vitro and the resin is separated using high tower separation technology.

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

[0095] The output of the pre-filter 201 is Q = 260t / h, and a backwashable filter element is filled therein. The inlet and outlet water pipes 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;

[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 the mixed bed. There are two high-speed mixed beds 202, and the two high-speed mixed beds 202 are used in parallel. The inlet and outlet main pipes of each high-speed mixed bed 202 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.

[0097] The in vitro regeneration system 203 adopts efficient resin separation and regeneration technology. After the resin fails, it is transported to the resin separation tower, and after backwashing and stratification, it is transported to the cation and anion resin regeneration tanks for regeneration. The in vitro regeneration system 203 is equipped with a DN1500 / DN900 resin separation tower 2031, a DN1000 cation resin regeneration and resin storage tank 2032, a DN800 anion resin regeneration tank 2033, and two regeneration flushing water pumps 2034. The regeneration flushing water uses desalted water for resin transportation and flushing. The resin separation tower 2031, the cation resin regeneration and resin storage tank 2032 and the anion resin regeneration tank 2033 are respectively connected to the wastewater resin catcher 207. The acid and alkali solution of the acid and alkali storage metering supply system 205 flows from the high-level storage tank into each metering box, and then is mixed into the specified concentration by the flushing water pump, acid and alkali injector, etc., and then sent to the regeneration tank for resin regeneration. A 4m 3The electric hot water tank 208 is heated to increase the temperature of the regenerated alkali solution so as to achieve the best regeneration effect.

[0098] Acid and alkali storage metering supply system 205: It is composed of acid and alkali storage tanks and necessary accessories. It stores HCl and NaOH for resin regeneration. The acid and alkali for regeneration are supplied by the market and transported by tank trucks to the acid and alkali depot where the acid and alkali pumps are unloaded. The acid and alkali are pumped to the high-level acid and alkali storage tank. The present invention sets a volume of 5m 3 There are one acid storage tank and one alkali storage tank. The regenerated hydrochloric acid is the first-class industrial hydrochloric acid of "Industrial Synthetic Hydrochloric Acid (GB320-2006)" or superior quality, using 31% hydrochloric acid, and the preparation concentration is 4% to 8%. The alkali is the first-class quality sodium hydroxide of HL-II specified in "High Purity Sodium Hydroxide (GB / T 11199-2006)", using 32% sodium hydroxide, and the preparation concentration is 4%.

[0099] The drainage water quality of the pre-filter 201 backwash and the high-speed mixed bed 202 is relatively good and is directly discharged into the ditch. The acid and alkaline wastewater generated by the resin regeneration of 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 equivalent, it only needs to be fully mixed, and a small amount of acid and alkali is added for adjustment, and air is introduced for sufficient stirring. After the neutralization pH value reaches 6-9, it is pumped up by a wastewater pump and discharged into the factory 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 resin during resin separation and air stirring in the neutralization tank. 3 Compressed air storage tank 2062 is used for backwashing of the pre-filter 201 for fine treatment, mixing, transportation and regeneration of mixed bed resin process gas, and gas for pneumatic valves in the condensate polishing system 2 is connected to the compressed air pipeline network of the instrument outlet of the self-heating machine professional gas storage tank.

[0101] The operation and backwashing of the condensate polishing system 2 equipment, the transportation, cleaning, regeneration, forward washing and mixing of the resin are all automatically controlled by the program. At the initial start-up of the unit, when the iron content of the condensate exceeds 1000μg / L, it will not enter the condensate polishing mixed bed system, and only the pre-filter 201 will be put into use to rapidly reduce the content of suspended iron in the system. When the pressure difference between the inlet and outlet main pipes 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 are retained, and the pre-filter 201 bypass is opened, the inlet and outlet valves of the pre-filter 201 are closed and the operation is stopped, and the backwashing pump 209 and compressed air are used for backwashing.

[0102] In the event of any of the following situations, the bypass system shall be able to open automatically and cut off the filter equipment in the condensate polishing system 2:

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

[0104] ②. Filter water inlet pressure>3.5MPa;

[0105] ③. The filter inlet and outlet pressure difference> 0.10MPa;

[0106] ④. The iron content in the filter outlet water 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 is opened, and the failed high-speed mixed bed 202 is decoupled, and the failed resin is transported to the extracorporeal regeneration system 203 for regeneration, and then the regenerated spare resin is transported to the high-speed mixed bed 202.

[0108] In the event of any of the following situations, the bypass system will automatically open and cut off the corresponding equipment in the condensate polishing system 2:

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

[0110] ② When the inlet condensate 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 greater than 3.5MPa.

[0113] According to the corrosiveness of the medium and the anti-corrosion requirements of the medium on the pipeline, the desalted water pipeline and resin delivery pipeline of the fine treatment system are made of stainless steel, and the condensate water 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. In order to prevent the outdoor water pipes from freezing in winter, electric heating + aluminum silicate insulation are used for the outdoor pipelines to prevent freezing and heat preservation measures.

[0114] The waterproof construction method of wastewater neutralization tank 204 is as follows:

[0115] In order to prevent the pool wall from cracking due to concrete shrinkage, the construction should consider leaving a post-casting strip along the length of the pool wall according to the requirements of the specification;

[0116] The pool wall concrete is fed in layers (before feeding, 50-100mm thick cement mortar with the same strength grade as the concrete is first laid at the bottom of the pool wall) and vibrated in layers. The thickness of the concrete is not more than 500mm, and the height is not more than 2m (otherwise, string tubes and other objects are added to guide the concrete into the mold). The vibration points are distributed and vibrated at a spacing of 100mm-150mm.

[0117] When pouring concrete, the new and old concrete should be combined in time, and cold joints are not allowed to appear. The old concrete surface should be covered and vibrated with new concrete before initial setting. When vibrating, the vibrating rod should be inserted into the old concrete for at least 100mm, otherwise, cold joints or loose vibration will appear on the new and old concrete surfaces.

[0118] In order to effectively prevent concrete cracking, the water-cement ratio of concrete is required to be strictly controlled (the water-cement ratio is controlled within 0.45). At the same time, Dura fiber or Foster fiber can be added to the concrete to enhance the crack resistance of the concrete.

[0119] After the construction of each section of the pool wall concrete, sacks are hung outside the pool wall formwork, and when the concrete starts to heat up, water is poured on it for curing, and the curing time is about 14 days.

[0120] Before pouring concrete into the column, first pour 50mm~100mm cement mortar with the same strength grade as the original concrete at the bottom, and then pour the concrete. The thickness of the concrete should not exceed 500mm, and the height should not exceed 2m. The beams should be poured obliquely in layers, and pushed forward obliquely in one direction. The slabs should be poured from one direction. During pouring, the concrete should be vibrated to make it dense.

[0121] The inner wall of the pool is anti-corrosive according to the design requirements. When using paint for anti-corrosion, if the surface is uneven, special putty can be used to fill it. After the putty is dry, it can be polished. After the treatment is completed, the paint can be applied. The paint should be applied in a criss-cross pattern, and each layer should be applied back and forth. The paint should be applied evenly without missing any spots.

[0122] The designed wastewater neutralization tank 204 has good crack resistance, good acid and alkali corrosion resistance and long service life.

[0123] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A gas boiler and condensing steam turbine water treatment system, characterized in that: include: A feed water treatment system (1) for supplying demineralized water to a boiler (4); A condensate polishing system (2) is used to treat condensate formed after the steam generated in the boiler (4) flows into the steam turbine (5); The chemical dosing system (3) is used to add ammonia to the treated feed water and condensate water, to add acetone oxime to the treated feed water, and to add phosphate to the boiler water.

2. A gas boiler and condensing steam turbine water treatment system according to claim 1, characterized in that: The feed water treatment system (1) comprises: an automatic heating device (102) connected in sequence to a raw water tank (101), a multi-media filter (103), a self-cleaning filter (104), an ultrafiltration device (105), a primary reverse osmosis device (106), a secondary reverse osmosis device (107), an EDI device (108) and a desalted water tank (109); the automatic heating device (102) is used to heat the incoming water to maintain the temperature at 20°C to 25°C, and the output of the automatic heating device (102) is 108m 3 / h, the heat medium required by the automatic heating device (102) is low-pressure steam with a pressure of less than 0.8Mpa and a temperature of 200°C; the filter material of the multi-media filter (103) is graded quartz sand and anthracite, and is connected to a backwashing water pump and a compressed air pipe for enhanced backwashing; the filtration accuracy of the self-cleaning filter (104) is 100μm, and its output is 108m 3 / h; the output of the ultrafiltration device (105) is 97m 3 / h, operation cycle 30min~60min, backwash time 30s~60s; the output of the first-stage reverse osmosis device (106) is 74m 3 / h, the output of the secondary reverse osmosis device (107) is 74m 3 / h; the output of the EDI device (108) is 60m 3 / h.

3. A gas boiler and condensing steam turbine water treatment system according to claim 1 or 2, characterized in that: The feed water treatment system (1) further comprises: 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 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 a reducing agent and a scale inhibitor to water flowing into the primary reverse osmosis device (106) via the ultrafiltration device (105), respectively; and the alkali dosing device (113) is used to add an alkali to water flowing into the secondary reverse osmosis device (107) via the primary reverse osmosis device (106).

4. A gas boiler and condensing steam turbine water treatment system according to claim 1, characterized in that: The first-stage reverse osmosis device (106) and the second-stage reverse osmosis device (107) both comprise: a reverse osmosis safety filter, a high-pressure pump, a reverse osmosis unit and a reverse osmosis water production tank which are connected in sequence, the filtering accuracy of the reverse osmosis safety filter being 5 μm; the inlet and outlet of the high-pressure pump are respectively provided with a low-pressure protection switch and a high-pressure protection switch, when the water supply is insufficient so that the water pressure at the inlet of the high-pressure pump is 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 1, characterized in that: The concentrated water produced by the EDI device (108) is sent to the reverse osmosis water production tank of the primary reverse osmosis device (106).

6. A gas boiler and condensing steam turbine water treatment system according to claim 1, characterized in that: The feed water treatment system (1) further comprises: a reverse osmosis flushing system (114) and two chemical cleaning systems (115); the reverse osmosis flushing system (114) uses the reverse osmosis effluent of the primary reverse osmosis device (106) to flush the reverse osmosis membrane of the reverse osmosis unit in the primary reverse osmosis device (106); the ultrafiltration device (105) is equipped with a chemical cleaning system (115); and the primary reverse osmosis device (106), the secondary reverse osmosis device (107) and the EDI device (108) are jointly equipped with a chemical cleaning system (115).

7. A gas boiler and condensing steam turbine water treatment system according to claim 1, characterized in that: The acid and alkaline wastewater produced by the primary reverse osmosis device (106), the secondary reverse osmosis device (107) and the EDI device (108) is discharged into a sump, and the acid and alkaline wastewater in the sump is pumped into the wastewater neutralization tank (204) of the condensate polishing system (2) through a corrosion-resistant submersible pump.

8. A gas boiler and condensing steam turbine water treatment system according to claim 1, characterized in that: The condensate polishing system (2) comprises: a pre-filter (201), a high-speed mixed bed (202) and an extracorporeal regeneration system (203) which are sequentially connected to the condensate outlet of the steam turbine (5); the acid and alkaline wastewater produced by the high-speed mixed bed (202) and the extracorporeal regeneration system (203) are discharged into a wastewater neutralization tank (204); the extracorporeal 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 extracorporeal regeneration system (203) and the wastewater neutralization tank (204) are respectively connected to a compressed air system (206).

9. A gas boiler and condensing steam turbine water treatment system according to claim 8, characterized in that: The output of the pre-filter (201) is Q=260 t / h, and a backwashable filter element is loaded therein. The inlet and outlet main pipes of the pre-filter (201) are provided with a bypass with a continuously adjustable opening of 0 to 100%. The output of the high-speed mixed bed (202) is Q=130 t / h. There are two high-speed mixed beds (202), and the two high-speed mixed beds (202) are used in parallel. The inlet and outlet main pipes of each high-speed mixed bed (202) are provided with a bypass with a continuously adjustable opening of 0 to 100%.

10. A gas boiler and condensing steam turbine water treatment system according to any one of claims 1 to 9, characterized in that: The in vitro regeneration system (203) comprises: a resin separation tower (2031), wherein the resin separation tower (2031) 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 respectively equipped with a regeneration flushing water pump (2034), and the regeneration flushing water pump (2034) is connected to the desalted water tank (109) of the feed water treatment system (1); and the acid and alkali storage metering supply system (205) supplies acid and alkali solution to the cation resin regeneration and resin storage tank (2032) and the anion resin regeneration tank (2033).

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