A method for recovering and utilizing wastewater of a condensate polishing system

Abstract

The application provides a method for recycling wastewater of a condensate polishing system, which comprises the following steps: in the process of operation and regeneration of a cation bed ion exchanger and / or a mixed bed ion exchanger in the condensate polishing system, removing solid impurities from the wastewater of at least one wastewater discharge operation corresponding to the characteristics of neutral and no solid impurities or neutral and solid impurities, and then sending the wastewater into a water tank before the inlet of a cation bed of a desalinated water preparation ion exchange system of a power station for utilization; and sending the wastewater of at least one wastewater discharge operation corresponding to the characteristics of acidity, from acidity to neutral and no solid impurities, alkalinity, or from alkalinity to neutral and no solid impurities to the inlet of a seawater desalination system for utilization by the seawater desalination system. The application classifies and recycles the wastewater with different characteristics in the condensate polishing system, avoids the complicated operation of acid-base neutralization treatment and sampling analysis of whether the wastewater is qualified, and reduces the amount of wastewater discharged to the environment by the power station and the amount of water taken from the environment by the power station.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of condensate polishing system, and particularly relates to a method for recycling waste water of a condensate polishing system. BACKGROUND

[0002] Nuclear power units (for example, VVER-1000 units) are usually configured with condensate polishing systems. The function of the condensate polishing system is to purify the condensate water quality, remove metal corrosion products and other metal impurities and ionic impurities. The condensate polishing system includes a mechanical filtration system (five anion bed ion exchangers), an ion exchange system (five mixed bed ion exchangers), an extracorporeal regeneration system and a waste water discharge system.

[0003] For example, the structure of the anion bed ion exchanger and the mixed bed ion exchanger in the condensate polishing system is the same, for example, a cylindrical filter with a diameter of 3.4 m, and normal operation is four in service and one in standby. The anion bed ion exchanger in the condensate polishing system is filled with resin of 14.6 cubic meters. The mixed bed ion exchanger in the condensate polishing system is filled with resin of 16.2 cubic meters, for example, 9.8 cubic meters of negative resin, 4.8 cubic meters of positive resin and 1.6 cubic meters of inert resin. When the anion bed ion exchanger and / or the mixed bed ion exchanger in the condensate polishing system fails to operate (the index exceeds the limit value), the anion bed ion exchanger and / or the mixed bed ion exchanger in the condensate polishing system that is in operation is taken out of operation for regeneration. The regeneration is to exchange the exhausted ion exchange resin with a suitable acid, alkali or salt solution to convert the resin into the required type.

[0004] The water used for flushing and regeneration before the anion bed ion exchanger and the mixed bed ion exchanger in the condensate polishing system are put into operation is desalted water; the chemical reagent used for neutralization of the waste liquid in the regeneration and waste water collection tank is hydrochloric acid and sodium hydroxide.

[0005] Before the resin in the five anion bed ion exchangers and the five mixed bed ion exchangers in the condensate polishing system fails to operate, the resin in the standby ion exchanger needs to be flushed to be qualified, and then the failed ion exchanger is taken out and the ion exchanger that is flushed to be qualified is put into operation. The waste water of the flushing is discharged into the waste water collection tank of the polishing system.

[0006] The resin in the ion exchanger of the condensate polishing system needs to be regenerated externally when it fails to operate. The condensate polishing system is provided with a polishing system anion exchanger resin regeneration filter. According to the actual regeneration process, the regeneration process includes: confirming that there is no influence on the maintenance of the polishing anion exchanger and checking the state of the valve and pump; filling the anion exchanger resin regeneration filter with water; transporting the resin in the condensate polishing system anion exchanger to the anion exchanger resin regeneration filter through water; transporting the residual resin in the condensate polishing system anion exchanger to the anion exchanger resin regeneration filter through compressed air; flushing the resin pipeline between the polishing anion exchanger and the anion exchanger resin regeneration filter; adjusting the water level in the anion exchanger resin regeneration filter to the U-shaped tube; using compressed air to scrub the resin in the anion exchanger resin regeneration filter; filling the anion exchanger resin regeneration filter with water; backwashing the anion resin in the anion exchanger resin regeneration filter; inputting regeneration liquid (acid liquid) into the resin in the anion exchanger resin regeneration filter; flushing the resin in the anion exchanger resin regeneration filter; filling the polishing anion exchanger with water; transporting the regenerated resin to the polishing anion exchanger through water; transporting the residual resin in the anion exchanger resin regeneration filter to the polishing anion exchanger through compressed air; flushing the resin pipeline between the polishing anion exchanger and the anion exchanger resin regeneration filter; filling the polishing anion exchanger with water; and flushing the standby pipeline, etc. The waste water generated by the regeneration and flushing standby operation is discharged into the polishing system waste water collection tank.

[0007] The mixed bed ion exchanger of the polishing treatment system is designed for middle extraction regeneration, and the regeneration system is provided with three regeneration filters, i.e. a cation exchange resin regeneration filter of the mixed bed ion exchanger of the polishing treatment system (referred to as a cation resin regeneration filter), an anion exchange resin regeneration filter of the mixed bed ion exchanger of the polishing treatment system (referred to as an anion resin regeneration filter), and a middle layer ion exchange resin storage filter with a diameter of 1.0 m. According to the actual regeneration process, the regeneration process includes the following steps: checking and confirming that the conditions for regeneration work are met; conveying the resin from the mixed bed ion exchanger of the polishing treatment system to the cation resin regeneration filter; backwashing and compacting the resin in the cation resin regeneration filter; conveying the resin in the cation resin regeneration filter to the anion resin regeneration filter; adding alkali to the resin in the anion resin regeneration filter and washing; conveying the resin in the anion resin regeneration filter to a part of the cation resin regeneration filter; scrubbing and backwashing the resin in the cation resin regeneration filter and the anion resin regeneration filter; conveying the remaining resin in the anion resin regeneration filter to the cation resin regeneration filter; scrubbing and backwashing the resin in the cation resin regeneration filter; separating the upper anion resin in the cation resin regeneration filter to the anion resin regeneration filter; backwashing the remaining resin in the cation resin regeneration filter; separating the remaining anion resin in the cation resin regeneration filter to the anion resin regeneration filter of the mixed bed ion exchanger of the polishing treatment system; backwashing the remaining resin in the cation resin regeneration filter; checking the resin separation effect, selecting the next operation according to the resin separation effect, performing acid and alkali regeneration when the resin separation effect meets the requirements, and continuing resin separation when the resin separation effect does not meet the requirements; flushing the pipeline between the cation resin regeneration filter and the anion resin regeneration filter; adding acid to the cation resin in the cation resin regeneration filter and flushing; adding alkali to the anion resin in the anion resin regeneration filter of the mixed bed ion exchanger of the polishing treatment system and flushing; conveying the anion resin in the anion resin regeneration filter to the cation resin regeneration filter; mixing the resin in the cation resin regeneration filter; flushing the resin in the cation resin regeneration filter; conveying the qualified resin to the mixed bed ion exchanger by water force, conveying the resin by compressed air, and flushing the resin pipeline; mixing the resin in the mixed bed ion exchanger, flushing the resin in the mixed bed ion exchanger to be qualified for standby, and the like. The wastewater generated by the regeneration and flushing standby operation of the mixed bed ion exchanger of the polishing treatment system is discharged into the polishing treatment system wastewater collection tank.

[0008] At present, the wastewater in the polishing treatment system wastewater collection tank is usually discharged after acid and alkali neutralization treatment and sampling analysis.

[0009] With the development of the country and the progress of the society, the country pays more and more attention to the treatment of water environment, and the environmental protection policy puts forward strict restrictions on the discharge standard and total amount of various wastewater, and encourages enterprises to adopt various water-saving new technologies to carry out deep treatment and recycling of various wastewater. The condensate polishing system is a necessary system for large units such as nuclear power and thermal power, however, the current recycling method of wastewater from the condensate polishing system is relatively complex and it is difficult to achieve near-zero discharge. SUMMARY

[0010] Therefore, the embodiments of the present application aim to provide a method for recycling wastewater from a condensate polishing system, which classifies and reuses wastewater with different characteristics in the condensate polishing system, so as to solve the problem that the current recycling method of wastewater from the condensate polishing system is relatively complex and it is difficult to achieve near-zero discharge.

[0011] The present application provides a method for recycling wastewater from a condensate polishing system, which comprises: in the process of operation and regeneration of a cation bed ion exchanger and / or a mixed bed ion exchanger in the condensate polishing system, the characteristics of the wastewater discharged in a plurality of wastewater discharge operations are neutral and without solid impurities, or neutral and with solid impurities, and the wastewater of at least one wastewater discharge operation corresponding to the wastewater with the characteristics of neutral and without solid impurities, or neutral and with solid impurities is sent to a water tank before the inlet of a cation bed of a desalted water preparation ion exchange system for utilization; the characteristics of the wastewater discharged in a plurality of wastewater discharge operations are acidic, from acidic to neutral and without solid impurities, alkaline, or from alkaline to neutral and without solid impurities, and the wastewater of at least one wastewater discharge operation corresponding to the wastewater is connected to the inlet of a seawater desalination system for utilization by the seawater desalination system.

[0012] In the above scheme, by classifying and dividing the characteristics of the wastewater discharged from the cation bed ion exchanger and / or the mixed bed ion exchanger in the condensate polishing system, the wastewater with different characteristics is classified and reused, thereby avoiding the complex operation of acid-base neutralization treatment and sampling analysis of whether it is qualified, reducing the amount of wastewater discharged to the environment by the power station and the amount of water taken from the environment by the power station, which is beneficial to the protection of the environment by the power station, and also reduces the pressure of the power station on the production of water source water supply, which is beneficial to the utilization of water resources by the power station.

[0013] In one embodiment of the present application, the solid impurities in the wastewater discharged from the at least one wastewater discharge operation corresponding to the wastewater discharged from the multiple wastewater discharge operations with the characteristics of neutral and without solid impurities, or neutral and with solid impurities are removed before the wastewater is sent to the water tank before the inlet of the positive bed of the ion exchange system for the preparation of desalted water of the power station for utilization, including: dividing the at least one wastewater discharge operation corresponding to the wastewater discharged from the multiple wastewater discharge operations with the characteristics of neutral and without solid impurities, or neutral and with solid impurities into a low-salinity wastewater discharge operation; connecting the wastewater of the low-salinity wastewater discharge operation to the intermediate-layer resin storage filter to remove the solid impurities in the wastewater of the low-salinity wastewater discharge operation by the intermediate-layer resin storage filter, and during the regeneration process of the mixed-bed ion exchanger in the condensed water polishing system, the inert resin in the multiple mixed-bed ion exchangers is filled with the intermediate-layer resin; sending the wastewater of the low-salinity wastewater discharge operation after the removal of the solid impurities to the water tank before the inlet of the positive bed of the ion exchange system for the preparation of desalted water of the power station for utilization; and treating the solid impurities in the wastewater of the low-salinity wastewater discharge operation as common solid waste.

[0014] In one embodiment of the present application, the wastewater discharged from the at least one wastewater discharge operation corresponding to the wastewater discharged from the multiple wastewater discharge operations with the characteristics of acid, from acid to neutral and without solid impurities, alkaline, or from alkaline to neutral and without solid impurities is connected to the inlet of the seawater desalination system for utilization by the seawater desalination system, including: dividing the at least one wastewater discharge operation corresponding to the wastewater discharged from the multiple wastewater discharge operations with the characteristics of acid, from acid to neutral and without solid impurities, alkaline, or from alkaline to neutral and without solid impurities into a high-salinity wastewater discharge operation; and connecting the wastewater of the high-salinity wastewater discharge operation to the inlet of the seawater desalination system for utilization by the seawater desalination system.

[0015] In one embodiment of the present application, the method further includes: sampling the wastewater discharged from at least one wastewater discharge operation in the process flow of the operation and regeneration of the positive-bed ion exchanger and / or the mixed-bed ion exchanger in the condensed water polishing system to determine the characteristics of the wastewater discharged from the at least one wastewater discharge operation. The characteristics of the wastewater include any one of no wastewater discharge, neutral and without solid impurities, neutral and with solid impurities, acid, from acid to neutral and without solid impurities, alkaline, and from alkaline to neutral and without solid impurities.

[0016] In one embodiment of the application, before sampling the wastewater discharged by at least one wastewater discharge operation in the process of the operation and regeneration of the anion ion exchanger and / or the mixed bed ion exchanger in the condensate polishing system, the method further comprises: determining at least one wastewater discharge operation in the process of the operation and regeneration of the anion ion exchanger in the condensate polishing system according to the process of the operation and regeneration of the anion ion exchanger in the condensate polishing system; and / or, determining at least one wastewater discharge operation in the process of the operation and regeneration of the mixed bed ion exchanger in the condensate polishing system according to the process of the operation and regeneration of the mixed bed ion exchanger in the condensate polishing system.

[0017] In one embodiment of the application, the plurality of wastewater discharge operations in the process of the operation and regeneration of the anion ion exchanger in the condensate polishing system comprises S1 pre-confirmation condition before putting into operation and washing, S2 putting into operation and washing, S3 pre-confirmation condition before regeneration, S4 filling water in the regeneration filter, S5 hydraulic resin transportation to the regeneration filter, S6 air pressure transportation to the regeneration filter, S7 washing pipeline, S8 drainage of the regeneration filter, S9 scrubbing, S10 filling water in the regeneration filter, S11 backwashing, S12 acid feeding, S13 regeneration washing, S14 filling water in the anion bed, S15 hydraulic resin transportation to the anion bed, S16 air pressure transportation to the anion bed, S17 washing pipeline, and S18 standby. The at least one wastewater discharge operation corresponding to the wastewater with neutral and no solid impurities comprises S2 putting into operation and washing, S5 hydraulic resin transportation to the regeneration filter, S6 air pressure transportation to the regeneration filter, S7 washing pipeline, S8 drainage of the regeneration filter, S15 hydraulic resin transportation to the regeneration filter, S16 air pressure transportation to the regeneration filter, S17 washing pipeline, and S18 standby. The at least one wastewater discharge operation corresponding to the wastewater with neutral and solid impurities comprises S11 backwashing. The at least one wastewater discharge operation corresponding to the wastewater with acid comprises S12 acid feeding. The at least one wastewater discharge operation corresponding to the wastewater with acid to neutral and no solid impurities comprises S13 regeneration washing.

[0018] In one embodiment of the application, the multiple wastewater discharge operations in the process flow of the operation and regeneration of the mixed bed ion exchanger of the condensate polishing system include S1 pre-confirmation condition before putting into operation and washing, S2 putting into operation and washing, S3 pre-confirmation condition before regeneration, S4 filling water in the cation resin regeneration filter, S5 hydraulic conveying resin to the cation resin regeneration filter, S6 air pressure conveying resin to the cation resin regeneration filter, S7 washing pipeline, S8 filling water in the cation resin regeneration filter, S9 backwashing, S10 compaction, S11 hydraulic conveying resin to the anion resin regeneration filter, S12 air pressure conveying to the anion resin regeneration filter, S13 washing pipeline, S14 alkali feeding and washing, S15 filling water in the cation resin regeneration filter, S16 conveying part of resin to the cation resin regeneration filter, S17 washing pipeline, S18 resin scrubbing in the cation resin regeneration filter, S19 resin backwashing in the cation resin regeneration filter, S20 resin scrubbing in the anion resin regeneration filter, S21 resin backwashing in the anion resin regeneration filter, S22 hydraulic conveying resin in the anion resin regeneration filter to the cation resin regeneration filter, S23 air pressure conveying resin in the anion resin regeneration filter to the cation resin regeneration filter, S24 washing pipeline, S25 resin scrubbing in the cation resin regeneration filter, S26 resin backwashing in the cation resin regeneration filter, S27 filling water in the anion resin regeneration filter, S28 first separation of anion resin in the cation resin regeneration filter, S29 resin backwashing in the cation resin regeneration filter, S30 second separation of anion resin in the cation resin regeneration filter, S31 resin backwashing in the cation resin regeneration filter, S32 checking resin separation effect, S33 washing pipeline, S34 acid feeding into resin in the cation resin regeneration filter, S35 resin washing in the cation resin regeneration filter, S36 alkali feeding into resin in the anion resin regeneration filter, S37 resin washing in the anion resin regeneration filter, S38 hydraulic conveying resin in the anion resin regeneration filter to the cation resin regeneration filter, S39 air pressure conveying resin in the anion resin regeneration filter to the cation resin regeneration filter, S40 washing pipeline, S41 mixed resin, S42 filling water in the cation resin regeneration filter, S43 washing of the cation resin regeneration filter, S44 hydraulic conveying resin to the mixed bed, S45 air pressure conveying resin to the cation resin regeneration filter, S46 washing pipeline, S47 mixed resin, S48 filling the mixed bed, and S49 standby.The at least one wastewater discharge operation corresponding to the wastewater characterized as neutral and having no solid impurities includes S9 backwash, S19 backwash of resin in the anion resin regeneration filter, S21 backwash of resin in the cation resin regeneration filter, S26 backwash of resin in the anion resin regeneration filter, S28 first separation of cation resin in the anion resin regeneration filter, S29 backwash of resin in the anion resin regeneration filter, S30 second separation of cation resin in the anion resin regeneration filter, and S31 backwash of resin in the anion resin regeneration filter. The at least one wastewater discharge operation corresponding to the wastewater characterized as acidic includes S34 acid into the anion resin regeneration filter. The at least one wastewater discharge operation corresponding to the wastewater characterized as from acidic to neutral and having no solid impurities includes S35 rinse of resin in the anion resin regeneration filter. The at least one wastewater discharge operation corresponding to the wastewater characterized as basic includes S36 base into the cation resin regeneration filter. The at least one wastewater discharge operation corresponding to the wastewater characterized as from basic to neutral and having no solid impurities includes S37 rinse of resin in the cation resin regeneration filter. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 Fig. 1 shows a flowchart of a method for recycling wastewater of a condensate polishing system according to an embodiment of the present application.

[0020] Figure 2 Fig. 2 shows a flowchart of a method for recycling wastewater of a condensate polishing system according to another embodiment of the present application.

[0021] Figure 3 Fig. 3 shows a flowchart of a method for recycling wastewater of a condensate polishing system according to yet another embodiment of the present application.

[0022] Figure 4 Fig. 1 shows a schematic diagram of a regeneration process of resin in a mixed bed ion exchanger.

[0023] Figure 5 Fig. 2 shows a schematic diagram of a wastewater treatment process for low-salt-content wastewater discharge operation according to an embodiment of the present application. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0025] Figure 1 Fig. 3 shows a schematic diagram of a method for wastewater recycling of a condensate polishing system according to an embodiment of the present application. As shown in Figure 1 The method comprises the following steps.

[0026] S100: In the process flow of operation and regeneration of the cation bed ion exchanger and / or the mixed bed ion exchanger in the condensate polishing system, the wastewater discharged in at least one wastewater discharge operation corresponding to the characteristics of neutral and no solid impurities or neutral and solid impurities is removed of solid impurities and then sent to a water tank before the inlet of the cation bed of the desalted water preparation ion exchange system in the power plant for utilization.

[0027] Specifically, through sampling analysis, it is found that the water used in each operation of the resin in the polishing cation bed and the mixed bed ion exchanger is desalted water, and the water quality of the wastewater discharged in at least one wastewater discharge operation corresponding to the characteristics of neutral and no solid impurities or neutral and solid impurities after removal of solid impurities is better than the water quality at the inlet of the unit desalted water preparation system. The wastewater is sent to the water tank before the inlet of the cation bed of the desalted water preparation ion exchange system in the power plant for utilization.

[0028] In at least one embodiment of the present application, the characteristics of the wastewater discharged in multiple wastewater discharge operations in the process flow of operation and regeneration of the cation bed ion exchanger in the condensate polishing system are shown in Table 1 below.

[0029] Table 1: Characteristics of wastewater discharged from the cation bed ion exchanger in the condensate polishing system

[0030]

[0031]

[0032] In at least one embodiment of the present application, the characteristics of the wastewater discharged in the plurality of wastewater discharge operations in the process of operation and regeneration of the mixed bed ion exchanger in the condensate polishing system are shown in Table 2 below.

[0033] Table 2: Characteristics of the wastewater discharged in the mixed bed ion exchanger in the condensate polishing system

[0034]

[0035]

[0036]

[0037] S200: The wastewater discharged in the at least one wastewater discharge operation corresponding to the characteristics of acidic, from acidic to neutral and without solid impurities, alkaline, or from alkaline to neutral and without solid impurities is connected to the inlet of the seawater desalination system for utilization by the seawater desalination system.

[0038] Specifically, it is found through sampling analysis that the wastewater discharged in the at least one wastewater discharge operation corresponding to the characteristics of acidic, from acidic to neutral and without solid impurities, alkaline, or from alkaline to neutral and without solid impurities mainly contains sodium ions and has very low hardness, and there is no tendency of fouling when using membrane concentration treatment, and is connected to the inlet of the seawater desalination system for utilization by the seawater desalination system.

[0039] It should be noted that the characteristics of the wastewater discharged in the at least one wastewater discharge operation can be known according to working experience or can be known by sampling, and the embodiments of the present application do not make specific limitations thereto.

[0040] According to the technical scheme provided in the embodiments of the present application, by classifying and dividing the characteristics of the wastewater discharged in the mixed bed ion exchanger and / or the mixed bed ion exchanger in the condensate polishing system, the wastewater with different characteristics is classified for reuse, thereby avoiding the complex operation of whether the wastewater is qualified after acid-base neutralization treatment and sampling analysis, reducing the amount of wastewater discharged by the power plant to the environment and the amount of water taken by the power plant from the environment, which is conducive to the protection of the environment by the power plant and also reduces the pressure of the power plant on the production of water source water supply, which is conducive to the utilization of water resources by the power plant. In addition, the method provided in the embodiments of the present application has small changes to the condensate polishing system and can utilize the original equipment of the system, which is economical.

[0041] Figure 2 Fig. 1 shows a flowchart of a method for recycling wastewater in a condensate polishing system according to an embodiment of the present application. Figure 2 The embodiment shown is Figure 1 A variant of the embodiment shown. As Figure 2 The embodiment shown corresponds to Figure 1The difference of the embodiment shown is that, before step S100, the method further comprises S300.

[0042] S300: sampling the wastewater discharged by at least one wastewater discharge operation in the process flow of the operation and regeneration of the anion exchanger and / or the mixed bed ion exchanger in the condensate polishing system to determine the characteristics of the wastewater discharged by the at least one wastewater discharge operation. The characteristics of the wastewater include any one of no wastewater discharge, neutral and no solid impurities, neutral and solid impurities, acidity, from acidity to neutral and no solid impurities, alkalinity, and from alkalinity to neutral and no solid impurities.

[0043] According to the technical scheme provided by the embodiment of the present application, by sampling the wastewater discharged by at least one wastewater discharge operation in the process flow of the operation and regeneration of the anion exchanger and / or the mixed bed ion exchanger in the condensate polishing system, the characteristics of the wastewater discharged by the at least one wastewater discharge operation are determined, which has a solid data basis and strong applicability.

[0044] In at least one embodiment of the present application, before step S300, the method further comprises S400 and / or S500.

[0045] S400: determining at least one wastewater discharge operation in the process flow of the operation and regeneration of the anion exchanger in the condensate polishing system according to the process flow of the operation and regeneration of the anion exchanger in the condensate polishing system.

[0046] For example, the process flow of the operation and regeneration of the anion exchanger in the condensate polishing system can be sorted out, and the wastewater discharge operation can be sorted out according to the process flow of the operation and regeneration of the anion exchanger in the condensate polishing system, for example, see Table 3 below.

[0047] Table 3: Wastewater discharge operation of the anion exchanger in the condensate polishing system

[0048]

[0049]

[0050] S500: determining at least one wastewater discharge operation in the process flow of the operation and regeneration of the mixed bed ion exchanger in the condensate polishing system according to the process flow of the operation and regeneration of the mixed bed ion exchanger in the condensate polishing system.

[0051] For example, the process flow of the operation and regeneration of the mixed bed ion exchanger in the condensate polishing system can be sorted out, and the wastewater discharge operation can be sorted out according to the process flow of the operation and regeneration of the mixed bed ion exchanger in the condensate polishing system, see Table 4 below.

[0052] Table 4: Condensate polishing system mixed bed ion exchanger wastewater discharge operation

[0053]

[0054]

[0055]

[0056]

[0057]

[0058] According to the technical scheme provided by the embodiment of the application, by matching the original design of the positive bed ion exchanger and the mixed bed ion exchanger in the condensate polishing system, all operations of the positive bed ion exchanger and the mixed bed ion exchanger in the condensate polishing system are decomposed, and the practicability is high.

[0059] Figure 3 Fig. 1 shows a flowchart of a method for recycling wastewater of a condensate polishing system according to another embodiment of the application. Figure 3 The embodiment shown is Figure 1 A variant of the embodiment shown. As Figure 3 The embodiment shown, and Figure 1 The difference between the embodiment shown and the embodiment shown is that steps S110 to S140 are Figure 1 A specific implementation mode of step S100 in the embodiment shown.

[0060] S110: In the process flow of the operation and regeneration of the positive bed ion exchanger and / or the mixed bed ion exchanger in the condensate polishing system, at least one wastewater discharge operation corresponding to the characteristics of the discharged wastewater being neutral and having no solid impurities or neutral and having solid impurities is divided into a low-salinity wastewater discharge operation.

[0061] S120: The wastewater of the low-salinity wastewater discharge operation is connected to an intermediate layer resin storage filter to remove the solid impurities in the wastewater of the low-salinity wastewater discharge operation by the intermediate layer resin storage filter. In the regeneration process of the mixed bed ion exchanger in the condensate polishing system, the inert resins filled in the plurality of mixed bed ion exchangers are intermediate layer resins.

[0062] Through sampling analysis, the main impurities in the wastewater of the low-salinity wastewater discharge operation discharged by the positive bed and the mixed bed ion exchanger in the condensate polishing system are broken resins and iron rust. If this part of the resins is directly sent to the wastewater tank, it will become a dangerous chemical according to the national management regulation of dangerous chemicals due to the contact with industrial wastewater, and the treatment cost of dangerous chemicals of the power station is increased.

[0063] For example, the regeneration system of the resin in the mixed bed ion exchanger of the condensate polishing system is originally designed for medium extraction regeneration, see Figure 4 : The original design of the regeneration process of the resin in the mixed bed ion exchanger, A is the mixed bed ion exchanger, B is the positive resin regeneration filter, C is the negative resin regeneration filter, D is the intermediate layer resin storage filter, the steps of the original design of the regeneration process are: 1 pour the intermediate layer resin into the positive resin regeneration filter; 2 pour the spent resin into the positive resin regeneration filter, and backwash with inert resin; 3 introduce the separated negative resin into the negative resin regeneration filter for regeneration; 4 introduce the separated intermediate layer resin into the intermediate layer resin storage filter; 5 pour the regenerated positive resin in the positive resin regeneration filter into the negative resin regeneration filter for mixing; 6 pour the regenerated resin back into the mixed bed. The intermediate layer resin storage filter is used to store the separated intermediate layer resin after each backwash, and this part of the resin needs to be poured into the mixed bed positive resin regeneration filter first when the next mixed bed ion exchange filter is regenerated, so as to participate in the regeneration of the next mixed bed resin, that is, five mixed beds share a set of intermediate layer resin.

[0064] Due to the fact that the amount of intermediate layer resin and the ratio of negative and positive resin cannot meet the design requirements, and the resin separation rate is low, the embodiment of the present application fills inert resin as intermediate layer resin for each mixed bed, so that five mixed beds no longer share a set of inert resin, cross contamination is eliminated and the resin separation rate is improved, the function of the D intermediate layer resin storage filter is cancelled, and the filter is given a new function. The D intermediate layer resin storage filter is connected before the low-salinity wastewater is discharged into the wastewater collection tank, and solid impurities in the low-salinity wastewater are removed by the filter.

[0065] S130: The low-salinity wastewater after removal of solid impurities is sent to the water tank before the inlet of the positive bed of the desalted water preparation ion exchange system for utilization.

[0066] S140: The solid impurities in the low-salinity wastewater are treated as ordinary solid waste.

[0067] Specifically, the low-salinity wastewater treatment process can be seen from Figure 5 : D is the intermediate layer resin storage filter, E is the water tank at the inlet of the positive bed of the desalted water preparation system, and the working process is 1 low-salinity wastewater is connected to D, 2 the treated low-salinity wastewater is sent to the water tank before the positive bed of the desalted water preparation system, 3 the unloaded solid impurities can be treated as ordinary solid waste, 4 water is loaded and compressed air is introduced when the solid impurities are unloaded.

[0068] According to the technical scheme provided in the embodiments of the present application, the solid impurities (such as broken resin) in the wastewater discharged in the operation and regeneration of the anion bed and the ion exchanger of the mixed bed are collected and treated, so that the solid impurities are prevented from entering the wastewater tank to become hazardous waste, the amount of hazardous chemicals in the power plant is reduced, and the treatment cost of the hazardous chemicals in the power plant is saved.

[0069] In at least one embodiment of the present application, steps S210 and S220 are Figure 1 a specific implementation of step S200 in the embodiment shown.

[0070] S210: At least one wastewater discharge operation corresponding to the characteristics of the wastewater discharged in the plurality of wastewater discharge operations, i.e. acidic, from acidic to neutral and without solid impurities, alkaline, or from alkaline to neutral and without solid impurities, is classified as a high-salt-content wastewater discharge operation.

[0071] S220: The wastewater of the high-salt-content wastewater discharge operation is connected to the inlet of the seawater desalination system for utilization by the seawater desalination system.

[0072] For example, according to the sampling results of the wastewater discharged by the anion bed ion exchanger of the condensate polishing system, the wastewater discharged by the anion bed ion exchanger of the condensate polishing system is classified and collected according to low-salt content and high-salt content (corresponding to steps S110 and S210 described above). According to the sampling results, the wastewater discharged by the anion bed ion exchanger of the condensate polishing system is classified and collected according to low-salt content and high-salt content as shown in Table 5 below.

[0073] Table 5: Classification of wastewater discharged by the anion bed ion exchanger of the condensate polishing system

[0074]

[0075]

[0076] In addition, according to the sampling results of the wastewater discharged by the mixed bed ion exchanger in the condensate polishing system, the wastewater discharged by the mixed bed ion exchanger in the condensate polishing system is classified and collected according to low-salt content and high-salt content (corresponding to steps S110 and S210 described above). According to the sampling results, the wastewater discharged by the mixed bed ion exchanger in the condensate polishing system is classified and collected according to low-salt content and high-salt content as shown in Table 6 below.

[0077] Table 6: Classification of wastewater discharged by the mixed bed ion exchanger of the condensate polishing system

[0078]

[0079]

[0080] In the embodiment of the present application, the multiple wastewater discharge operations in the operation and regeneration of the ion exchanger of the condensate polishing system are classified and collected to divide into low-salinity wastewater discharge operation and high-salinity wastewater discharge operation, so as to facilitate subsequent targeted treatment of the low-salinity wastewater discharge operation and the high-salinity wastewater discharge operation, and more facilitate the rational use of water resources of the power plant.

[0081] It should be noted that the combination of various technical features in the embodiments of the present application is not limited to the combination manner described in the embodiments of the present application or the combination manner described in the specific embodiments, and all the technical features described in the present application can be freely combined or combined in any manner, unless contradictory to each other.

[0082] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method of condensate polishing system wastewater recycling, characterized by, The method comprises the following steps: In the process of operation and regeneration of the cation bed ion exchanger and / or the mixed bed ion exchanger in the condensate polishing system, the wastewater discharged in at least one of the plurality of wastewater discharge operations is neutral and free of solid impurities, or neutral and contains solid impurities, and the wastewater after removal of the solid impurities is sent to a water tank before the inlet of the cation bed of the ion exchange system for desalted water preparation in the power station for utilization. The wastewater discharged in at least one of the plurality of wastewater discharge operations is acidic, from acidic to neutral and free of solid impurities, alkaline, or from alkaline to neutral and free of solid impurities, and the wastewater is connected to the inlet of the seawater desalination system for utilization by the seawater desalination system.

2. The method of claim 1, wherein, The method of utilizing the wastewater discharged in at least one of the plurality of wastewater discharge operations, wherein the wastewater is neutral and free of solid impurities, or neutral and contains solid impurities, after removal of the solid impurities, comprises the following steps: At least one of the plurality of wastewater discharge operations is divided into a low-salinity wastewater discharge operation, wherein the wastewater discharged in the low-salinity wastewater discharge operation is neutral and free of solid impurities, or neutral and contains solid impurities. The wastewater in the low-salinity wastewater discharge operation is connected to an intermediate-layer resin storage filter to remove the solid impurities in the wastewater in the low-salinity wastewater discharge operation by the intermediate-layer resin storage filter, wherein the plurality of mixed bed ion exchangers are respectively filled with inert resins as intermediate-layer resins during the regeneration of the mixed bed ion exchanger in the condensate polishing system. The wastewater in the low-salinity wastewater discharge operation after removal of the solid impurities is sent to a water tank before the inlet of the cation bed of the ion exchange system for desalted water preparation in the power station for utilization. The solid impurities in the wastewater in the low-salinity wastewater discharge operation are treated as ordinary solid waste.

3. The method of claim 1, wherein, The method of utilizing the wastewater discharged in at least one of the plurality of wastewater discharge operations, wherein the wastewater is acidic, from acidic to neutral and free of solid impurities, alkaline, or from alkaline to neutral and free of solid impurities, comprises the following steps: At least one of the plurality of wastewater discharge operations is divided into a high-salinity wastewater discharge operation, wherein the wastewater discharged in the high-salinity wastewater discharge operation is acidic, from acidic to neutral and free of solid impurities, alkaline, or from alkaline to neutral and free of solid impurities. The wastewater in the high-salinity wastewater discharge operation is connected to the inlet of the seawater desalination system for utilization by the seawater desalination system.

4. The method of claim 1, wherein, The method further comprises the following steps: The wastewater discharged in at least one of the plurality of wastewater discharge operations in the process of operation and regeneration of the cation bed ion exchanger and / or the mixed bed ion exchanger in the condensate polishing system is sampled to determine the characteristics of the wastewater discharged in the at least one wastewater discharge operation, wherein the characteristics of the wastewater include any one of no wastewater discharge, neutral and free of solid impurities, neutral and containing solid impurities, acidity, from acidity to neutrality and free of solid impurities, alkalinity, and from alkalinity to neutrality and free of solid impurities.

5. The method of claim 4, wherein, Before sampling the wastewater discharged by at least one wastewater discharge operation in the process flow of operation and regeneration of the anion bed ion exchanger and / or the mixed bed ion exchanger in the condensate polishing system, the method further comprises: determining at least one wastewater discharge operation in the process flow of operation and regeneration of the anion bed ion exchanger in the condensate polishing system according to the process flow of operation and regeneration of the anion bed ion exchanger in the condensate polishing system; and / or determining at least one wastewater discharge operation in the process flow of operation and regeneration of the mixed bed ion exchanger in the condensate polishing system according to the process flow of operation and regeneration of the mixed bed ion exchanger in the condensate polishing system.

6. The method of any one of claims 1 to 5, wherein the plurality of wastewater discharge operations in the process flow of operation and regeneration of the anion bed ion exchanger in the condensate polishing system comprises S1 pre-commissioning condition, S2 commissioning flush, S3 pre-regeneration condition, S4 regeneration filter priming, S5 hydraulic resin transfer to regeneration filter, S6 air pressure transfer to regeneration filter, S7 flush line, S8 regeneration filter drain, S9 scrubbing, S10 regeneration filter priming, S11 backwash, S12 acid feed, S13 regeneration flush, S14 anion bed priming, S15 hydraulic resin transfer to anion bed, S16 air pressure transfer to anion bed, S17 flush line, and S18 standby, wherein the at least one wastewater discharge operation corresponding to the characteristic of neutral and no solid impurities of the wastewater comprises S2 commissioning flush, S5 hydraulic resin transfer to regeneration filter, S6 air pressure transfer to regeneration filter, S7 flush line, S8 regeneration filter drain, S15 hydraulic resin transfer to regeneration filter, S16 air pressure transfer to regeneration filter, S17 flush line, and S18 standby, the at least one wastewater discharge operation corresponding to the characteristic of neutral and solid impurities of the wastewater comprises S11 backwash, the at least one wastewater discharge operation corresponding to the characteristic of acid of the wastewater comprises S12 acid feed, the at least one wastewater discharge operation corresponding to the characteristic of from acid to neutral and no solid impurities of the wastewater comprises S13 regeneration flush.

7. The method of any one of claims 1 to 5, wherein The multiple wastewater discharge operations in the process flow of the operation and regeneration of the mixed bed ion exchanger in the condensate polishing system include S1 pre-confirmation condition before commissioning and flushing, S2 commissioning and flushing, S3 pre-regeneration confirmation condition, S4 filling water in the cation resin regeneration filter, S5 hydraulic conveying resin to the cation resin regeneration filter, S6 air pressure conveying resin to the cation resin regeneration filter, S7 flushing pipeline, S8 filling water in the cation resin regeneration filter, S9 backwashing, S10 compaction, S11 hydraulic conveying resin to the anion resin regeneration filter, S12 air pressure conveying to the anion resin regeneration filter, S13 flushing pipeline, S14 alkali flushing, S15 filling water in the cation resin regeneration filter, S16 conveying part of resin to the cation resin regeneration filter, S17 flushing pipeline, S18 resin scrubbing in the cation resin regeneration filter, S19 resin backwashing in the cation resin regeneration filter, S20 resin scrubbing in the anion resin regeneration filter, S21 resin backwashing in the anion resin regeneration filter, S22 hydraulic conveying of resin in the anion resin regeneration filter to the cation resin regeneration filter, S23 air pressure conveying of resin in the anion resin regeneration filter to the cation resin regeneration filter, S24 flushing pipeline, S25 resin scrubbing in the cation resin regeneration filter, S26 resin backwashing in the cation resin regeneration filter, S27 filling water in the anion resin regeneration filter, S28 first separation of anion resin in the cation resin regeneration filter, S29 resin backwashing in the cation resin regeneration filter, S30 second separation of anion resin in the cation resin regeneration filter, S31 resin backwashing in the cation resin regeneration filter, S32 checking resin separation effect, S33 flushing pipeline, S34 acid into resin in the cation resin regeneration filter, S35 flushing of resin in the cation resin regeneration filter, S36 alkali into resin in the anion resin regeneration filter, S37 flushing of resin in the anion resin regeneration filter, S38 hydraulic conveying of resin in the anion resin regeneration filter to the cation resin regeneration filter, S39 air pressure conveying of resin in the anion resin regeneration filter to the cation resin regeneration filter, S40 flushing pipeline, S41 mixed resin, S42 filling water in the cation resin regeneration filter, S43 flushing of the cation resin regeneration filter, S44 hydraulic conveying resin to the mixed bed, S45 air pressure conveying resin to the cation resin regeneration filter, S46 flushing pipeline, S47 mixed resin, S48 filling the mixed bed, and S49 standby. Among them, the wastewater is characterized as neutral and free of solid impurities. At least one wastewater discharge operation includes: S2 commissioning flushing, S5 hydraulic transport of resin to the cation regeneration filter, S6 compressed air transport of resin to the cation regeneration filter, S7 flushing pipeline, S10 compaction, S11 hydraulic transport of resin to the anion regeneration filter, S12 compressed air transport to the anion regeneration filter, S13 flushing pipeline, S14 alkali inlet flushing, S16 transporting part of the resin to the cation regeneration filter, S17 flushing pipeline, S22 hydraulic transport of resin from the anion regeneration filter to the cation regeneration filter, S2 3. Compressed air delivery of resin from the anion regeneration filter to the cation regeneration filter; S24 flushing line; S33 flushing line; S38 hydraulic delivery of resin from the anion regeneration filter to the cation regeneration filter; S39 compressed air delivery of resin from the anion regeneration filter to the cation regeneration filter; S40 flushing line; S41 mixing; S42 filling the cation regeneration filter with water; S43 flushing the cation regeneration filter; S44 hydraulic delivery of resin to the mixed bed; S45 compressed air delivery of resin to the cation regeneration filter; S46 flushing line; S47 mixing and S49 standby. The wastewater is characterized as neutral and contains solid impurities. At least one wastewater discharge operation includes: S9 backwashing, S19 cation regeneration filter internal resin backwashing, S21 anion regeneration filter internal resin backwashing, S26 cation regeneration filter internal resin backwashing, S28 first separation cation regeneration filter internal anion resin, S29 cation regeneration filter internal resin backwashing, S30 second separation cation regeneration filter internal anion resin, and S31 cation regeneration filter internal resin backwashing. The wastewater is characterized by its acidity, and at least one wastewater discharge operation involves the introduction of acid into the resin of the S34 cation exchange resin regeneration filter. The wastewater is characterized as being acidic to neutral and free of solid impurities. At least one wastewater discharge operation includes resin flushing within the S35 cation exchange filter. The wastewater is characterized by alkalinity, corresponding to at least one wastewater discharge operation involving the introduction of alkali into the resin of the S36 anion exchange resin regeneration filter. The wastewater is characterized as being alkaline to neutral and free of solid impurities. At least one wastewater discharge operation includes resin flushing within the S37 anion exchange resin regeneration filter.

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