CN116643514A - Operation control method of power plant pretreatment system based on water balance - Google Patents

Operation control method of power plant pretreatment system based on water balance Download PDF

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Publication number
CN116643514A
CN116643514A CN202310396735.XA CN202310396735A CN116643514A CN 116643514 A CN116643514 A CN 116643514A CN 202310396735 A CN202310396735 A CN 202310396735A CN 116643514 A CN116643514 A CN 116643514A
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flow
pretreatment
pretreatment system
liquid level
water tank
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张林涛
顿小宝
刘世雄
何信林
郭云飞
李昭
张向涛
王凯
赵威
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Xian Thermal Power Research Institute Co Ltd
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Xian Thermal Power Research Institute Co Ltd
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    • GPHYSICS
    • G05CONTROLLING; REGULATING
    • G05BCONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B19/00Programme-control systems
    • G05B19/02Programme-control systems electric
    • G05B19/04Programme control other than numerical control, i.e. in sequence controllers or logic controllers
    • G05B19/042Programme control other than numerical control, i.e. in sequence controllers or logic controllers using digital processors
    • G05B19/0423Input/output
    • GPHYSICS
    • G05CONTROLLING; REGULATING
    • G05BCONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B2219/00Program-control systems
    • G05B2219/20Pc systems
    • G05B2219/25Pc structure of the system
    • G05B2219/25257Microcontroller

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  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Automation & Control Theory (AREA)
  • Control Of Non-Electrical Variables (AREA)

Abstract

The invention discloses a power plant pretreatment system operation control method based on water balance, wherein before a pretreatment device is started, an operator needs to confirm a target liquid level value of a clean water tank; when the pretreatment equipment is started, determining the flow of the pretreatment system through a control system; according to the height of the current liquid level of the clean water tank and the target liquid level, the liquid level difference between the current liquid level of the clean water tank and the target liquid level is reduced by adjusting the flow of the pretreatment system, so that the flow of the pretreatment system is matched with the flow of the pretreatment follow-up system, the current liquid level of the clean water tank is maintained at the target liquid level, and further continuous and stable operation of pretreatment equipment is maintained, water balance control between the pretreatment system and the pretreatment follow-up system is realized, short-time and wide-range fluctuation of the flow of the pretreatment system is reduced, the relation between the opening of a butterfly valve and the inflow flow is controlled, the sufficient residence time and the suspended matter separation effect of medicines are ensured, and the aim of stable water quality of effluent of the pretreatment system is further realized.

Description

Operation control method of power plant pretreatment system based on water balance
Technical Field
The invention belongs to the technical field of power plant water treatment, and relates to an operation control method of a power plant pretreatment system based on water balance.
Background
The purpose of the pretreatment of the boiler make-up water of the thermal power plant is to remove suspended matters, colloid, organic matters and other partial impurities in raw water, so that the treated water quality meets the requirement of subsequent water treatment equipment on the water quality of the inlet water. The common pretreatment process comprises coagulation clarification, filtration, active carbon adsorption and the like, wherein common equipment in the coagulation clarification process comprises a mechanical stirring clarification tank, a hydraulic circulation clarification tank, a pulse clarification tank and a suspension clarification tank, and the raw water is clarified by adding medicines such as coagulant and the like. Common equipment in the filtering process comprises a common rapid filter, a siphon filter, a gravity type valveless filter, a pressure type filter, a pore-changing filter and the like, and can effectively filter suspended granular impurities in water.
The effluent water of the pretreatment system has a great influence on the operation of a subsequent system, taking a mechanical acceleration clarification tank as an example, in a first reaction chamber, the medicine needs to be fully mixed, in a second reaction chamber, the medicine needs to be ensured to have enough reaction time, in a separation chamber, proper flow rate needs to be met, the separation of clear water and suspended matters is ensured, if the treatment capacity of the pretreatment system is frequently changed, frequent fluctuation of the flow rate easily causes the medicine to be not fully mixed, suspended matters cannot be separated and settled, even the pool turning site is caused, and the effluent water quality is influenced. Meanwhile, the water inlet regulating valve of the pretreatment system is usually an electric butterfly valve, the water inlet flow is regulated by the opening of the butterfly valve, but the linearity between the opening of the butterfly valve and the pipeline flow is poor, firstly, the effective interval of the opening of the valve is smaller, and secondly, the opening is slightly regulated in the effective interval to correspond to larger change of the flow, so that inconvenience is brought to the regulation of the flow. Therefore, how to solve the water balance control between the pretreatment system and the subsequent system, reduce the short-time and large-scale fluctuation of the flow of the pretreatment system, control the relation between the opening of a butterfly valve and the inflow flow, ensure the sufficient residence time of the medicines and the separation effect of suspended matters, and ensure the quality of the discharged water to reach the standard is a problem to be solved urgently.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides a power plant pretreatment system operation control method based on water balance, thereby achieving the purposes of automatically and stably controlling the flow of the pretreatment system and further achieving the stable water quality of the effluent of the pretreatment system.
The invention is realized by the following technical scheme:
a method for controlling the operation of a pretreatment system of a power plant based on water balance comprises,
s1, before the pretreatment equipment 4 is started, an operator needs to confirm a target liquid level value of a clear water tank;
s2, when the pretreatment equipment 4 is started, the pretreatment system flow is determined through the control system, and the calculation method of the pretreatment system flow is as follows:
wherein the matching coefficient is 1;
s3, according to the level of the current liquid level of the clean water tank 5 and the target liquid level, the liquid level difference between the current liquid level of the clean water tank 5 and the target liquid level is reduced by adjusting the flow of the pretreatment system, so that the flow of the pretreatment system is matched with the flow of the pretreatment follow-up system, the current liquid level of the clean water tank 5 is maintained at the target liquid level, and then the continuous and stable operation of the pretreatment equipment 4 is maintained,
preferably, the control system in S2 determines that the flow rate of the pretreatment system is specifically: firstly judging whether a subsequent pretreatment system is in an operating state, when the subsequent pretreatment system is in the operating state, taking the sum of the flow of the subsequent pretreatment system as the reference flow of the pretreatment system, calculating the difference value between the current liquid level of the clean water tank 5 and the target liquid level, multiplying the ratio of the difference value and the target liquid level by a matching coefficient to obtain an adjustment ratio, and adjusting the reference flow of the pretreatment system by using the adjustment ratio to obtain the flow value of the pretreatment system.
Preferably, when the pretreatment device 4 is started in S3, if the current liquid level of the clean water tank 5 is lower than the target liquid level, after the pretreatment system flow is adjusted, the pretreatment system flow is larger than the subsequent pretreatment system flow, along with the operation of the pretreatment device 4, the liquid level difference between the current liquid level of the clean water tank 5 and the target liquid level gradually decreases, the pretreatment system flow gradually maintains the same as the subsequent pretreatment system flow until the current liquid level of the clean water tank 5 reaches the target liquid level, at this time, the pretreatment system flow and the subsequent pretreatment system flow are completely matched, the current liquid level of the clean water tank 5 is maintained at the target liquid level, and the pretreatment device 4 continuously and stably operates.
Preferably, when the pretreatment device 4 is started in S3, if the current liquid level of the clean water tank 5 is higher than the target liquid level, after the pretreatment system flow is adjusted, the pretreatment system flow is smaller than the subsequent pretreatment system flow, and as the pretreatment device 4 operates, the liquid level difference between the current liquid level of the clean water tank 5 and the target liquid level gradually decreases, the pretreatment system flow gradually maintains the same as the subsequent pretreatment system flow until the current liquid level of the clean water tank reaches the target liquid level, at this time, the pretreatment system flow and the subsequent pretreatment system flow are completely matched, the current liquid level of the clean water tank is maintained at the target liquid level, and the pretreatment device 4 continuously and stably operates.
Preferably, the target level value of the clean water tank in S1 is determined by combining a recent or current day water usage schedule with a subsequent start-stop schedule of the pretreatment device.
Preferably, before the pretreatment device 4 is started in S1, an operator needs to confirm the flow value under the optimal operation condition of the pretreatment system.
Preferably, when the pretreatment follow-up equipment is not started, the pretreatment system only prepares water for the clean water tank 5, the pretreatment system runs stably, when the effluent quality reaches the standard, the flow of the pretreatment system at the moment is set as the flow value under the optimal operation condition of the pretreatment system, the pretreatment system runs continuously and stably until the current liquid level of the clean water tank 5 reaches the target liquid level, and then the pretreatment system stops running.
Preferably, a single set or a plurality of sets of pretreatment equipment exist in the pretreatment system, when the flow of the pretreatment system is adjusted, the single set or the plurality of sets of pretreatment equipment in the pretreatment system uniformly divide the current operation flow of the pretreatment system, and the operation flow of each set of pretreatment equipment does not exceed the rated treatment capacity of the pretreatment system.
Preferably, when the flow of the pretreatment system is adjusted, the flow adjustment precision is reduced by the control system, and when the flow of the pretreatment system reaches within the rated flow range of the pretreatment system of which the target value is +/-5%, the target value of the flow adjustment of the pretreatment system is considered to be reached; the target value of the pretreatment system flow is a pretreatment system flow value when the current liquid level of the clear water tank is lifted to the target liquid level.
Preferably, when the flow of the pretreatment system is adjusted, the adjustment rate of the flow of the pretreatment system is kept consistent with the treatment capacity of the pretreatment system through the control system; the control system adopts a DCS control system.
Compared with the prior art, the invention has the following beneficial technical effects:
the invention provides an operation control method of a power plant pretreatment system based on water balance, which is characterized in that before pretreatment equipment is started, an operator needs to confirm a target liquid level value of a clean water tank; when the pretreatment equipment is started, determining the flow of the pretreatment system through a control system; according to the height of the current liquid level of the clean water tank and the target liquid level, the liquid level difference between the current liquid level of the clean water tank and the target liquid level is reduced by adjusting the flow of the pretreatment system, so that the flow of the pretreatment system is matched with the flow of the pretreatment follow-up system, the current liquid level of the clean water tank is maintained at the target liquid level, and further continuous stable operation of pretreatment equipment is maintained, water balance control between the pretreatment system and the pretreatment follow-up system is realized, short-time wide-range fluctuation of the flow of the pretreatment system is reduced, the relation between the opening of a butterfly valve and the inflow flow is controlled, the sufficient residence time and the suspended matter separation effect of medicines are ensured, and the purposes of automatically and stably controlling the flow of the pretreatment system and stabilizing the water quality of effluent of the pretreatment system are achieved.
Further, after the flow of the pretreatment system is adjusted by the control method, if the current liquid level of the clean water tank is lower than the target liquid level during starting, the flow of the pretreatment system is larger than the flow of the subsequent system after the system is adjusted, at the moment, the pretreatment system can ensure the water supply of the subsequent system and can also maintain the water supplementing of the clean water tank, the larger the liquid level difference value is, the faster the water supplementing is, the liquid level difference is gradually reduced along with the running of the equipment, the flow of the pretreatment system is gradually maintained to be the same as the flow of the subsequent system until the current liquid level of the clean water tank reaches the target liquid level, at the moment, the flow of the pretreatment system is completely matched with the flow of the subsequent system, the liquid level of the water tank is maintained at the target liquid level, and the equipment continuously and stably runs. Otherwise, if the current liquid level of the clean water tank is higher than the target liquid level during starting, after the system is adjusted, the flow of the pretreatment system is smaller than the flow of the follow-up system, at the moment, the follow-up system can consume a part of the current liquid level of the clean water tank, the larger the liquid level difference value is, the faster the consumption is, along with the running of equipment, the liquid level difference is gradually reduced, the flow of the pretreatment system is gradually maintained to be the same as the flow of the follow-up system until the current liquid level of the clean water tank reaches the target liquid level, at the moment, the flow of the pretreatment system is completely matched with the flow of the follow-up system, the liquid level of the water tank is maintained at the target liquid level, and the equipment continuously and stably runs.
Further, when the flow of the pretreatment system is adjusted, in order to avoid the phenomenon that suspended matters are separated and settled poorly and even the pool is turned over due to the too fast change of the flow, the speed of the flow adjustment of the pretreatment system is controlled to be about 100% of the rated flow of the pretreatment system by the control system, so that the stable and even change process is ensured in the flow adjustment process of the pretreatment system, and the phenomenon that flocculates cannot be settled due to the too fast rising flow rate is avoided.
Further, when the flow is regulated, the flow regulation precision is reduced by the control system, and when the flow reaches within the range of a target value (+/-) (5% of rated throughput of the pretreatment system, t/h), the regulated target value is considered to be reached, so that the stable and continuous operation of the pretreatment system under the required flow is realized.
Drawings
FIG. 1 is a diagram of a power plant pretreatment system operation control system based on water balance.
FIG. 2 is a logic diagram of preprocessing system flow adjustment.
In the figure, a pretreatment water inlet regulating valve 1, a pretreatment water supply pump 2, a pretreatment flowmeter 3, a pretreatment device 4, a clean water tank 5, a clean water tank current level meter 6, a makeup water treatment water supply pump 7, a makeup water treatment flowmeter 8, a makeup water treatment device 9, an industrial water system water supply pump 10, an industrial water system flowmeter 11 and an industrial water system device 12 are shown.
Detailed Description
In order that those skilled in the art will better understand the present invention, a technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in which it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present invention without making any inventive effort, shall fall within the scope of the present invention.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.
A method for controlling the operation of a water balance based power plant pretreatment system, as shown in fig. 2, comprises,
s1, before the pretreatment equipment 4 is started, an operator needs to confirm a target liquid level value of a clear water tank and a flow value under the optimal operation condition of a pretreatment system; the pretreatment device 4 is generally a coagulating sedimentation and filtration device, such as a coagulating sedimentation clarifier, an inclined plate clarifier, etc. The makeup water treatment apparatus 9 may be a whole membrane process or a membrane process+ion exchange treatment apparatus.
The target level value of the clean water tank in S1 is determined by combining a recent or current day water consumption plan and a subsequent start-stop plan of the pretreatment equipment.
And S1, when the subsequent equipment is not started, the pretreatment system only prepares water for the clean water tank 5, the pretreatment system stably operates, and when the effluent quality reaches the standard, the flow value is the flow value under the optimal operation condition of the pretreatment system.
S2, when the pretreatment equipment 4 is started, the pretreatment system flow is determined through the control system, and the calculation method of the pretreatment system flow is as follows:
wherein the matching coefficient is 1;
s3, according to the height of the current liquid level of the clean water tank 5 and the target liquid level, the liquid level difference between the current liquid level of the clean water tank 5 and the target liquid level is reduced by adjusting the flow of the pretreatment system, so that the flow of the pretreatment system is matched with the flow of a subsequent pretreatment system, the current liquid level of the clean water tank 5 is maintained at the target liquid level, and then continuous and stable operation of the pretreatment equipment 4 is maintained.
In S3, when the pretreatment device 4 is started, if the current liquid level of the clean water tank 5 is lower than the target liquid level, after the pretreatment system flow is adjusted, the pretreatment system flow is larger than the pretreatment subsequent system flow, along with the operation of the pretreatment device 4, the liquid level difference between the current liquid level of the clean water tank 5 and the target liquid level gradually decreases, the pretreatment system flow gradually maintains the same as the pretreatment subsequent system flow until the current liquid level of the clean water tank 5 reaches the target liquid level, at this time, the pretreatment system flow is completely matched with the pretreatment subsequent system flow, the current liquid level of the clean water tank 5 is maintained at the target liquid level, and the pretreatment device 4 continuously and stably operates.
In S3, when the pretreatment device 4 is started, if the current liquid level of the clean water tank 5 is higher than the target liquid level, after the pretreatment system flow is adjusted, the pretreatment system flow is smaller than the pretreatment subsequent system flow, along with the operation of the pretreatment device 4, the liquid level difference between the current liquid level of the clean water tank 5 and the target liquid level gradually decreases, the pretreatment system flow gradually maintains the same as the pretreatment subsequent system flow until the current liquid level of the clean water tank reaches the target liquid level, at this time, the pretreatment system flow is completely matched with the pretreatment subsequent system flow, the current liquid level of the clean water tank is maintained at the target liquid level, and the pretreatment device 4 continuously and stably operates.
When the flow of the pretreatment system is adjusted, the single or multiple pretreatment devices in the pretreatment system divide the current operation flow of the pretreatment system equally, and the operation flow of each pretreatment device does not exceed the rated treatment capacity of the pretreatment system.
When the flow of the pretreatment system is regulated, the flow regulation precision is reduced by the control system, and when the flow of the pretreatment system reaches within the range of target value + -5% of rated treatment capacity of the pretreatment system, the target value of the flow regulation of the pretreatment system is considered to be reached.
When the flow of the pretreatment system is regulated, the regulating speed of the flow of the pretreatment system is kept consistent with the treatment capacity of the pretreatment system through the control system.
The control system adopts a DCS control system.
In the case of example 1,
the operation control method of the power plant pretreatment system based on water balance is shown in fig. 1, and comprises a pretreatment water inlet regulating valve 1, a pretreatment water supply pump 2, a pretreatment flowmeter 3, a pretreatment device 4, a clean water tank 5, a current liquid level meter 6 of the clean water tank, a makeup water treatment water supply pump 7, a makeup water treatment flowmeter 8, a makeup water treatment device 9, an industrial water system water supply pump 10, an industrial water system flowmeter 11 and an industrial water system device 12. The equipment or the measuring point is connected with a DCS or other control systems, and the states of the equipment and the measuring point can be monitored and operated through the DCS or other control systems. Raw water of the pretreatment system enters the pretreatment system through a pretreatment water inlet regulating valve 1 by a pipeline, and the water inlet flow can be regulated by regulating the opening of the regulating valve. After raw water enters the pretreatment feed pump 2, the raw water is fed into the pretreatment equipment 4, a pretreatment flowmeter 3 is installed on a pipeline between the pretreatment equipment and the pretreatment feed pump, flow rate is monitored, water discharged from the pretreatment equipment 4 enters the clear water tank 5, a current level meter 6 of the clear water tank is installed on the clear water tank 5, and the water level of the water tank can be determined through the level meter. The pretreatment system mainly comprises a makeup water treatment system and an industrial water system, wherein the makeup water treatment system water is a clean water tank 5, a makeup water treatment flow meter 8 is arranged on a pipeline between the makeup water treatment water pump 7 and the makeup water treatment equipment 9, the flow rate is monitored, the industrial water system water is the clean water tank 5, the industrial water system water pump 10 is arranged on a pipeline between the industrial water system water pump 10 and the industrial water system equipment 12, and an industrial water system flow meter 11 is arranged on the pipeline between the industrial water system water pump and the industrial water system equipment, and the flow rate is monitored.
Before the pretreatment equipment is started, an operator needs to confirm two data, namely, a target value of the current liquid level 6 of the clean water tank and a flow value under the optimal operation condition of the pretreatment system. The target value of the current liquid level 6 of the clean water tank can be determined by combining a recent or today water consumption plan, a follow-up equipment start-stop plan and the like, and when the equipment operates, the pretreatment system can control the operation flow on the premise of ensuring the follow-up system flow to reach the target value of the liquid level. When the following equipment is not started, the pretreatment system only prepares water for the clean water tank 5, and at the moment, the stable operation of the pretreatment system is ensured as much as possible, the fluctuation is reduced, and the better effluent quality is kept, so that the flow under the optimal operation condition is determined by combining the previous operation experience of the pretreatment system, and the pretreatment system is operated under the condition.
As shown in fig. 2, when the pretreatment device is started, the control system first determines the flow rate of the pretreatment system, first determines whether the subsequent pretreatment system is in an operation state, and when the subsequent pretreatment system is in the operation state, uses the sum of the flow rates of the subsequent pretreatment system as the reference flow rate of the pretreatment system, calculates the difference between the current liquid level and the target liquid level of the clean water tank, multiplies the ratio of the difference to the target liquid level by a matching coefficient to obtain an adjustment ratio, and adjusts the reference flow rate of the pretreatment system by using the adjustment ratio, namely the flow rate value of the pretreatment system. Wherein the matching coefficient defaults to 1, and can be modified according to the actual conditions of different projects. The flow calculation method of the pretreatment system comprises the following steps:
after the flow of the pretreatment system is regulated according to the method, if the current liquid level of the clean water tank is lower than the target liquid level during starting, the flow of the pretreatment system is larger than the flow of the subsequent system after the system is regulated, at the moment, the pretreatment system can ensure the water supply of the subsequent system and can also maintain the water supplementing of the clean water tank, the larger the liquid level difference value is, the faster the water supplementing is, the liquid level difference is gradually reduced along with the running of the equipment, the flow of the pretreatment system is gradually maintained to be the same as the flow of the subsequent system until the current liquid level of the clean water tank reaches the target liquid level, at the moment, the flow of the pretreatment system is completely matched with the flow of the subsequent system, the liquid level of the water tank is maintained at the target liquid level, and the equipment continuously and stably runs. Otherwise, if the current liquid level of the clean water tank is higher than the target liquid level during starting, after the system is adjusted, the flow of the pretreatment system is smaller than the flow of the follow-up system, at the moment, the follow-up system can consume a part of the current liquid level of the clean water tank, the larger the liquid level difference value is, the faster the consumption is, along with the running of equipment, the liquid level difference is gradually reduced, the flow of the pretreatment system is gradually maintained to be the same as the flow of the follow-up system until the current liquid level of the clean water tank reaches the target liquid level, at the moment, the flow of the pretreatment system is completely matched with the flow of the follow-up system, the liquid level of the water tank is maintained at the target liquid level, and the equipment continuously and stably runs.
In one of the preferred embodiments, when the subsequent system is not in the operation state, the operation target of the pretreatment system is to raise the current liquid level of the clean water tank to the target liquid level, so that the continuous and stable operation of the pretreatment system is only required to be maintained, and the effluent quality reaches the standard. At this time, the flow of the pretreatment system is set to be the flow value under the optimal operation condition of the pretreatment system, so that the continuous and stable operation requirement of the pretreatment system is met, and the pretreatment system is stopped after the liquid level reaches the target liquid level.
In the preferred embodiment, when the flow of the pretreatment system is adjusted, in order to avoid the phenomenon of poor separation and sedimentation effects of suspended matters and even pool turning caused by too fast change of the flow, the speed of the flow adjustment of the pretreatment system is controlled to be about 100% of the treatment capacity of the pretreatment system by a control system, so that the stable and uniform change process is ensured in the flow adjustment process of the pretreatment system, and the phenomenon that flocculates cannot be settled caused by too fast rising flow is avoided.
In one preferred embodiment, the inlet water regulating valve of the pretreatment system is usually an electric butterfly valve, the inlet water flow is regulated by the opening of the butterfly valve, but the linearity between the opening of the butterfly valve and the pipeline flow is poor, firstly, the effective interval of the opening of the valve is small, secondly, the opening is slightly regulated in the effective interval to correspond to the large change of the flow, when the flow is regulated, the small opening regulation of the valve possibly causes the excessive correction of the flow, so that the flow continuously fluctuates up and down and cannot be stabilized. Considering that the flow calculation of the pretreatment system can realize the dynamic adjustment of the flow, the flow is not required to be controlled to be at a very accurate target value through a water inlet butterfly valve, therefore, when the flow is adjusted, the flow adjustment precision is reduced through the control system, and when the flow reaches the range of the target value (+/-) (5% of the rated throughput of the pretreatment system, t/h), the adjusted target value is considered to be reached, so that the stable and continuous operation of the pretreatment system under the required flow is realized.
In one preferred embodiment, there may be a single set or multiple sets of pretreatment devices in the pretreatment system, and when the flow is adjusted, the single set or multiple sets of devices equally divide the current operation flow of the pretreatment system, and the operation flow of each set of pretreatment devices does not exceed the rated treatment capacity.
Based on judging whether the subsequent equipment operates or not, the invention correspondingly adjusts the operation flow of the pretreatment system according to the level of the water tank based on the total flow of the subsequent equipment; meanwhile, the flow adjustment speed of the pretreatment system is controlled, the matching value of the flow during adjustment of the water inlet adjusting valve is controlled, and the flow of the pretreatment system can be adjusted in advance and stably.
The above description is only of the preferred embodiments of the present invention, and is not intended to limit the present invention in any way; those skilled in the art will readily appreciate that the present invention may be implemented as shown in the drawings and described above; however, those skilled in the art will appreciate that many modifications, adaptations, and variations of the present invention are possible in light of the above teachings without departing from the scope of the invention; meanwhile, any equivalent changes, modifications and evolution of the above embodiments according to the essential technology of the present invention still fall within the scope of the present invention.

Claims (10)

1. A method for controlling the operation of a pretreatment system of a power plant based on water balance is characterized by comprising the following steps,
s1, before the pretreatment equipment is started, an operator needs to confirm a target liquid level value of a clear water tank;
s2, when the pretreatment equipment is started, the flow of the pretreatment system is determined through the control system, and the flow of the pretreatment system is calculated as follows:
wherein the matching coefficient is 1;
s3, according to the height of the current liquid level and the target liquid level of the clean water tank, the liquid level difference between the current liquid level and the target liquid level of the clean water tank is reduced by adjusting the flow of the pretreatment system, so that the flow of the pretreatment system is matched with the flow of a subsequent pretreatment system, the current liquid level of the clean water tank is maintained at the target liquid level, and continuous and stable operation of pretreatment equipment is further maintained.
2. The method for controlling the operation of a pretreatment system of a power plant based on water balance according to claim 1, wherein the control system determines the flow rate of the pretreatment system in S2 specifically as follows: firstly judging whether a pretreatment subsequent system is in an operation state, when the pretreatment subsequent system is in the operation state, taking the sum of the flow of the pretreatment subsequent system as the reference flow of the pretreatment system, calculating the difference value between the current liquid level of the clear water tank and the target liquid level, multiplying the ratio of the difference value and the target liquid level by a matching coefficient to obtain an adjustment ratio, and adjusting the reference flow of the pretreatment system by using the adjustment ratio to obtain the flow value of the pretreatment system.
3. The operation control method of a power plant pretreatment system based on water balance according to claim 1, wherein in S3, when the pretreatment device is started, if the current liquid level of the clean water tank is lower than the target liquid level, after the pretreatment system flow is adjusted, the pretreatment system flow is larger than the subsequent pretreatment system flow, as the pretreatment device is operated, the liquid level difference between the current liquid level of the clean water tank and the target liquid level gradually decreases, the pretreatment system flow is gradually maintained to be the same as the subsequent pretreatment system flow until the current liquid level of the clean water tank reaches the target liquid level, at this time, the pretreatment system flow is completely matched with the subsequent pretreatment system flow, the current liquid level of the clean water tank is maintained at the target liquid level, and the pretreatment device continuously and stably operates.
4. The operation control method of a power plant pretreatment system based on water balance according to claim 1, wherein in S3, when the pretreatment device is started, if the current liquid level of the clean water tank is higher than the target liquid level, after the pretreatment system flow is adjusted, the pretreatment system flow is smaller than the subsequent pretreatment system flow, as the pretreatment device is operated, the liquid level difference between the current liquid level of the clean water tank and the target liquid level gradually decreases, the pretreatment system flow is gradually maintained to be the same as the subsequent pretreatment system flow until the current liquid level of the clean water tank reaches the target liquid level, at this time, the pretreatment system flow is completely matched with the subsequent pretreatment system flow, the current liquid level of the clean water tank is maintained at the target liquid level, and the pretreatment device 4 continuously and stably operates.
5. The method for controlling the operation of a pretreatment system of a power plant based on water balance according to claim 1, wherein the target level value of the clean water tank in S1 is determined by combining a recent or current water consumption schedule and a subsequent start-stop schedule of the pretreatment equipment.
6. The method for controlling operation of a pretreatment system of a power plant based on water balance according to claim 1, wherein before the pretreatment device is started in S1, an operator needs to confirm a flow value under an optimal operation condition of the pretreatment system.
7. The operation control method of a power plant pretreatment system based on water balance according to claim 6, wherein the flow value under the optimal operation condition of the pretreatment system is obtained by making water only for a clean water tank by the pretreatment system when the pretreatment follow-up equipment is not started, the pretreatment system is stably operated, when the effluent quality reaches the standard, the flow of the pretreatment system at the moment is set to be the flow value under the optimal operation condition of the pretreatment system, and the pretreatment system is continuously and stably operated until the current liquid level of the clean water tank reaches the target liquid level, and then the pretreatment system is stopped.
8. The method for controlling the operation of a pretreatment system of a power plant based on water balance according to claim 1, wherein a single or multiple sets of pretreatment devices are arranged in the pretreatment system, when the flow of the pretreatment system is adjusted, the single or multiple sets of pretreatment devices in the pretreatment system uniformly divide the current operation flow of the pretreatment system, and the operation flow of each set of pretreatment devices does not exceed the rated treatment capacity of the pretreatment system.
9. The method for controlling the operation of a pretreatment system of a power plant based on water balance according to claim 1, wherein the accuracy of the flow adjustment is reduced by the control system when the flow of the pretreatment system is adjusted, and the target value of the flow adjustment of the pretreatment system is considered to be reached when the flow of the pretreatment system is within a range of a target value + -5% of a rated flow of the pretreatment system; the target value of the pretreatment system flow is a pretreatment system flow value when the current liquid level of the clear water tank is lifted to the target liquid level.
10. The method for controlling the operation of a pretreatment system of a power plant based on water balance according to claim 1, wherein when the flow rate of the pretreatment system is adjusted, the adjustment rate of the flow rate of the pretreatment system is kept consistent with the throughput of the pretreatment system by the control system; the control system adopts a DCS control system.
CN202310396735.XA 2023-04-13 2023-04-13 Operation control method of power plant pretreatment system based on water balance Pending CN116643514A (en)

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