A water resource cascade utilization process for thermal power plants

Abstract

This invention discloses a cascaded water resource utilization process for thermal power plants, which divides water resources into industrial water, domestic water, and reclaimed water. The domestic water refers to the water used for daily life in the power plant; the industrial water includes water for fire fighting, chemical water treatment, boiler systems, and oil systems; and the reclaimed water includes water used in the coal yard and desulfurization process systems. The industrial water and domestic water are connected to the municipal water supply, which provides the water source for both. The industrial wastewater after the industrial water is used is treated by a wastewater treatment system to provide the water source for the reclaimed water. This invention can realize the cascaded utilization of water resources, greatly reduce the total amount of various types of wastewater, and reduce the total amount of raw water used in the plant, which is of profound significance for water conservation in thermal power plants.

Description

Technical Field

[0001] This invention relates to the field of water treatment technology for thermal power plants, specifically a process for the cascade utilization of water resources in thermal power plants. Background Technology

[0002] Currently, my country's water shortage is becoming increasingly severe. In some areas with severe water scarcity, water has become a major factor restricting industrial development. Thermal power plants are major industrial water consumers, and their heating units consume more water than pure condensing thermal power plants. Therefore, practicing water conservation, rational water use, and strengthening water management to fully utilize water resources is of significant economic and social importance to enterprises.

[0003] Currently, the water balance design of domestic thermal power plants or combined heat and power plants does not fully consider the cascade utilization of water resources. Furthermore, the independent operation of each unit in the power plant and the single water usage method generally adopt the method of single-use and disposal, which leads to many problems: first, the total amount of various types of wastewater in the plant is large; second, the wastewater is mixed together and is not easy to classify and recycle; and third, the total amount of raw water used in the plant is large. Summary of the Invention

[0004] The purpose of this invention is to provide a cascade utilization process for water resources in thermal power plants to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a cascade utilization process for water resources in thermal power plants, which divides water resources into industrial water, domestic water and reclaimed water;

[0006] The domestic water refers to the water used for domestic purposes in the power plant; the industrial water refers to the water used for fire fighting, chemical water treatment, and boiler systems in the power plant; the reused water refers to the water used in the coal yard and the water used in the desulfurization process system.

[0007] The industrial water and domestic water are connected to the tap water pipes, and the tap water provides the water source for both. The industrial wastewater after the industrial water is used is treated by the wastewater treatment system to provide the water source for reuse.

[0008] Furthermore, it also includes a mechanical ventilation cooling tower system in a power plant, wherein the water used in the mechanical ventilation cooling tower system comes from one or both of industrial water and reclaimed water, and the wastewater discharged from the mechanical ventilation cooling tower system is treated by a wastewater treatment system to provide a water source for reclaimed water.

[0009] Furthermore, the water used for chemical water treatment includes normal water vapor loss, water for external heating, closed-loop cooling water for each auxiliary machine, water for reverse osmosis, water for filter, and water for ultrafiltration. The wastewater generated from reverse osmosis, filter, and ultrafiltration is treated by the wastewater treatment system and then added to the reuse water.

[0010] Furthermore, the wastewater treatment system includes a multi-media filter, an ultrafiltration wastewater tank, a No. 1 wastewater tank, a No. 2 wastewater tank, a No. 3 wastewater tank, and wastewater treatment equipment. The No. 1, No. 2, and No. 3 wastewater tanks are used for classified recycling of wastewater. The water treated by the wastewater treatment equipment is used as a source of reuse water. The ultrafiltration wastewater tank is used to recycle the backwash water from the filter and ultrafiltration, and the backwash water is filtered by the multi-media filter to provide a water source for industrial water.

[0011] Furthermore, the boiler system water is sourced from demineralized water produced by chemical water treatment. Wastewater from the boiler's regular cooling water is collected through the unit's drainage tank. Water within the specified quality standards is directly used as the source of industrial water. Wastewater exceeding the specified quality standards is treated by the wastewater treatment system and used as the source of reused water.

[0012] Furthermore, the wastewater generated after the use of water in the oil system enters the No. 3 wastewater pool and is treated by the wastewater treatment equipment before being used as a water source for reuse. The uses of the industrial water also include other miscellaneous uses and unforeseen water uses.

[0013] Furthermore, the water used in the coal yard includes water for hydraulic cleaning, water for coal conveying equipment, water for car washing machines, water for dust removal, water for flushing roads in the plant area, and water for spraying in the coal yard. The wastewater from the hydraulic cleaning, coal conveying equipment, and car washing machines is treated after coal removal and then reused as a source of water for reuse.

[0014] Furthermore, the water source of the desulfurization process water system comes from the concentrated water formed after the wastewater treatment system. The desulfurization wastewater generated after the desulfurization system is used is treated with chemicals to remove heavy metals and suspended solids, and then used for spraying in the coal yard, or enters the electrolytic seawater chlorination system to produce chlorine for sterilization and algae removal in the circulating water system.

[0015] Furthermore, the domestic sewage generated after the use of domestic water is treated by sewage treatment equipment and then collected in a greywater tank as a source of water for greening. The reused water is also used for flushing toilets in the power plant, and the sewage after flushing is collected in the greywater tank.

[0016] Compared with the prior art, the beneficial effects of the present invention are:

[0017] This invention addresses the common problem in power plants of generating a wide variety of wastewater in large quantities, without proper classification and recycling based on water quality. It proposes a tiered water resource utilization technology solution. This solution categorizes and recycles wastewater based on its source and quality, and further classifies and tiers its utilization according to the specific processes of thermal power plants or combined heat and power plants and the water quality requirements of each water usage point. It fully utilizes existing equipment in thermal power plants, and is cost-effective and easy to implement. This approach ensures the full utilization of water resources, significantly reduces water consumption in power plant operations, and yields substantial economic and social benefits. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of a process for cascade utilization of water resources in a thermal power plant according to the present invention. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] like Figure 1 As shown, a cascade utilization process for water resources in a thermal power plant divides water resources into industrial water, domestic water, and reclaimed water. Domestic water is used for daily life in the power plant; industrial water is used for fire fighting, chemical water treatment, boiler system water, etc.; reclaimed water is used for coal yard water and desulfurization process water system water. Industrial water and domestic water are connected to the municipal water supply, and the municipal water supply provides the water source for both. Industrial wastewater after industrial water use is treated by the wastewater treatment system to provide the water source for reclaimed water.

[0021] The water resource utilization process also includes the mechanical ventilation cooling tower system in the power plant. The water used by the mechanical ventilation cooling tower system comes from one or both of industrial water and reclaimed water. The wastewater discharged from the mechanical ventilation cooling tower system is treated by the wastewater treatment system to provide a water source for reclaimed water. The water used by the mechanical ventilation cooling tower system includes auxiliary machine cooling water, air conditioning equipment cooling water and cooling tower water. After use, some of these waters are consumed by wind and evaporation.

[0022] The water quality control indicators for the mechanical ventilation cooling tower system are as follows. When the water quality exceeds the following indicators, increase the amount of water replenished and discharged from the mechanical ventilation cooling tower system until the water quality is within the range of the following control indicators.

[0023]

[0024]

[0025] Chemical water treatment water includes normal water vapor loss, water for external heating, closed-loop cooling water for various auxiliary machines, water for reverse osmosis, water for filter, and water for ultrafiltration. Among them, the wastewater generated by reverse osmosis, filter, and ultrafiltration is treated by the wastewater treatment system and then added to the reuse water.

[0026] The wastewater treatment system includes a multi-media filter, an ultrafiltration wastewater tank, a No. 1 wastewater tank, a No. 2 wastewater tank, a No. 3 wastewater tank, and wastewater treatment equipment. The No. 1, No. 2, and No. 3 wastewater tanks are used for classified recycling of wastewater. The water treated by the wastewater treatment equipment is used as a source of reuse water. The ultrafiltration wastewater tank is used to recycle the backwash water from the filter and ultrafiltration. The backwash water is filtered by the multi-media filter and then used as a source of industrial water.

[0027] Wastewater from the cooling tower, recycled water after treatment of coal-containing wastewater system, wastewater from unit drainage tank, and wastewater from ultrafiltration and reverse osmosis chemical cleaning are all collected in Wastewater Pool No. 3. Reverse osmosis flushing drainage is collected in Wastewater Pool No. 1, and backwashing wastewater from multi-media filter is collected in Wastewater Pool No. 2.

[0028] The boiler system water is demineralized water produced by chemical water treatment. Wastewater after the boiler's cooling water is used is collected through the unit's drainage tank. If the water quality is within the following range, it is directly used as the source of industrial water. If the wastewater exceeds the following range, it is treated by the treatment system and used as the source of reused water.

[0029] Serial Number project unit control value 1 PH / 6.5～8.5 2 Turbidity NTU ≤5 3 iron μg / L ≤300 4 suspended matter mg / L ≤30 5 chloride ions mg / L ≤250 6 hardness mmol / L ≤4.5 7 alkalinity mmol / L ≤3.5 8 COD mg / L ≤3

[0030] Wastewater generated after the use of water in the oil system enters the No. 3 wastewater pond and is treated by the wastewater treatment equipment before being used as a water source for reuse. The uses of industrial water also include other miscellaneous uses and unforeseen water uses.

[0031] Water used in coal yards includes water for hydraulic cleaning, water for coal conveying equipment, water for car washing machines, water for dust removal, water for flushing roads in the plant area, and water for spraying coal yards. Wastewater from hydraulic cleaning, coal conveying equipment, and car washing machines is treated to remove coal and then reused as a source of water for reuse.

[0032] The desulfurization process water system originates from the concentrated water generated after the wastewater treatment system. The desulfurization wastewater produced after use is treated with chemicals to remove heavy metals and suspended solids before being used for spraying in the coal yard or entering the seawater electrolysis chlorination system for chlorination, which is then used for sterilization and algae control in the circulating water system.

[0033] Using concentrated water from reverse osmosis as the desulfurization process water significantly reduces the amount of makeup water needed for circulating water, which in turn indirectly reduces the amount of makeup water needed for the desulfurization tower.

[0034] Domestic sewage generated after the use of domestic water is treated by sewage treatment equipment and then collected in a greywater tank. It is used as a source of water for greening. The reused water is also used for flushing toilets in the power plant. The sewage after flushing is collected in the greywater tank.

[0035] The water used for flushing toilets throughout the plant was converted to reuse water, allowing the drainage from each unit to be reused for flushing where water quality requirements are not high.

[0036] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A process for water resource cascade utilization in a thermal power plant, characterized in that: The water resource is divided into industrial water, domestic water and reuse water; The domestic water is domestic water in the power plant; the industrial water is fire-fighting water, water for chemical water treatment, water for boiler system and oil system water in the power plant; the reuse water is coal yard water and desulfurization process water system water; The industrial water and domestic water are connected with the tap water pipe, and the tap water provides water source for the two; the industrial wastewater after use of the industrial water is treated by the wastewater treatment system to provide water source for the reuse water; It also includes a mechanical ventilation cooling tower system in the power plant, the water source of the mechanical ventilation cooling tower system is from one or both of the industrial water and the reuse water, and the waste water of the mechanical ventilation cooling tower system is treated by the wastewater treatment system to provide water source for the reuse water; the water for chemical water treatment includes normal water vapor loss, water for external heating, closed cooling water of each auxiliary machine, reverse osmosis self-use water, filter self-use water and ultrafiltration self-use water, the wastewater generated by the reverse osmosis self-use water, the filter self-use water and the ultrafiltration self-use water is treated by the wastewater treatment system to supplement into the reuse water; the wastewater treatment system includes a multi-medium filter, an ultrafiltration wastewater pool, a first wastewater pool, a second wastewater pool, a third wastewater pool and a wastewater treatment device, the first wastewater pool, the second wastewater pool and the third wastewater pool are used for classified recovery of wastewater, and the wastewater treated by the wastewater treatment device is used as the source of the reuse water, the ultrafiltration wastewater pool is used for recovery of backwashing drainage of the filter and the ultrafiltration, and the backwashing drainage is filtered by the multi-medium filter to provide water source for the industrial water; The boiler fixed cooling water is sourced from the industrial water, the water for boiler system is sourced from the desalted water prepared by the chemical water treatment, the wastewater after use of the boiler fixed cooling water is collected by the unit drainage tank, and the water quality within a certain index is directly used as the water source of the industrial water, and the wastewater exceeding the index is treated by the wastewater treatment system to be used as the water source of the reuse water; the wastewater after use of the oil system water enters the third wastewater pool and is treated by the wastewater treatment device to be used as the water source of the reuse water, the use of the industrial water also includes other miscellaneous and unforeseen water; the coal yard water includes water for hydraulic cleaning, water for coal conveying equipment, water for car washer, water for dust removal, water for flushing of plant area road and water for coal yard spraying, the waste water of the three of the water for hydraulic cleaning, the water for coal conveying equipment and the water for car washer is treated by coal removal to be used as the source of the reuse water.

2. The water resource cascade utilization process for thermal power plants according to claim 1, characterized in that: The water source of the desulfurization process water system is the concentrated water after treatment by the wastewater treatment system, the desulfurization wastewater system after use of the desulfurization system is treated by dosing to remove heavy metals and suspended solids, and is used for coal yard spraying or enters the electrolytic seawater chlorine system to prepare chlorine and is used for sterilization and algae killing in the circulating water system.

3. The water resource cascade utilization process for thermal power plants according to claim 1, characterized in that: The domestic sewage after use of the domestic water is treated by the sewage treatment device to enter the middle water pool to be collected and used as the source of the greening water, and the reuse water is also used for flushing of toilets in the power plant, and the sewage after flushing is collected in the middle water pool.

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