CN104991579A - System and method for controlling concentration ratio of open type circulating cooling water system - Google Patents

Abstract

The invention relates to a system and method for controlling the concentration ratio of an open type circulating cooling water system. The system for controlling the concentration ratio of the open type circulating cooling water system includes a control system and a cooling tower; a cooling tower water tank with a cooling tower water tank liquidometer is arranged below the cooling tower; the bottom of the cooling tower water tank is provided with a pollution discharge pipeline; the pollution discharge pipeline is provided with a circulating water conductivity meter, a circulating water temperature gauge, a pollution discharge electric control valve and a pollution discharge flowmeter; a water entering pipeline used for supplementing the cooling tower water tank with water is arranged above the cooling tower water tank; and the water entering pipeline is provided with a water supplementation flowmeter, a water supplementation conductivity meter, a water supplementation electric control valve and a water supplementation temperature gauge, wherein the water supplementation electric control valve is connected with the cooling tower water tank liquidometer. With the system and method of the invention adopted, automatic continuous and stable water supplementation and pollution discharge of the open type circulating cooling water system can be realized; automatic continuous on-line monitoring on the concentration ratio of circulating water can be realized; and concentration ratio fluctuation which is caused by intermittent water supplementation and pollution discharge of the circulating cooling water system can be avoided, so that the quality of the circulating water can be stabilized.

Description

A kind of system and method controlling Open recirling cooling water system concentration rate

Technical field

The invention belongs to technology of industrial recirculating cooling water treatment field, be specifically related to a kind of system and method controlling Open recirling cooling water system concentration rate.

Background technology

Open recirling cooling water system in operational process due to vaporization loss be not with leak water in salinity, the dissolved salts in recirculated water is constantly concentrated, and the ratio through concentrated recirculated water salt content and circulating water system salt content is called concentration rate.At present, the concentration rate of open type circulating water water system controls generally to take with under type, namely first labor measurement calculates concentration rate sometime, then according to the concentration rate manual adjustments circulating cooling make-up water amount of gained and blowdown flow rate, thus recycling water formulation concentration rate is at setting range.

Because the salt content in recirculated water cannot on-line monitoring, the power plant adopting the circulation cooling water system of open pattern all cannot on-line continuous monitoring concentration rate, generally by adopting the chloride ion content in regular labor measurement recirculated water and circulating cooling make-up water to calculate.The method can not reflect the concentration rate of actual motion in time, has certain hysteresis quality.

By the concentration rate of labor measurement, operations staff is regular recycling water formulation rate of water make-up and blowdown flow rate again.When the concentration rate measuring gained exceedes setting value, open blowoff valve and blowdown is carried out to circulation; When the concentration rate of mensuration gained is lower than setting value, close Circulating water effluent valve.The moisturizing of circulation is by manually regularly carrying out according to cooling tower liquid level.Be uncontinuity operation due to circulating cooling make-up water and blowdown and lag behind the change of recirculated water concentration rate, cause the concentration rate fluctuation range of circulation larger, reduce even at double or increase, thus cause circulating water quality unstable, blowdown flow rate is increased when concentration rate is lower, waste valuable water resource, corrosion and the fouling risk of cooling system when concentration rate is higher, can be increased again.Meanwhile, because existing recirculated water control system automaticity is lower, it is large that operations staff measures the workload such as concentration rate, operated valve.

Summary of the invention

For solving prior art Problems existing, the object of this invention is to provide a kind of system and method controlling Open recirling cooling water system concentration rate, the open type circulation of application the method, can realize monitoring the on-line continuous of concentration rate, and according to the data of Real-Time Monitoring, realize recirculated water automatic water supplement and blowdown by control system, make circulating cooling make-up water and continuous, stable the carrying out of blowdown operation.

For achieving the above object, the present invention adopts following technical scheme:

A kind of system controlling Open recirling cooling water system concentration rate, comprise control system and cooling tower, the pond of cooling tower with pond of cooling tower liquid level gauge is provided with below described cooling tower, be provided with blow-off line bottom pond of cooling tower, blow-off line be provided with recirculated water conductivity meter, circulating water temperature meter and blowdown electric control valve; Recirculated water conductivity meter is all connected with control system with circulating water temperature meter;

Be provided with for the inlet channel of pond of cooling tower supplementing water above pond of cooling tower, inlet channel is provided with moisturizing conductivity meter, moisturizing electric control valve and moisturizing thermometer, moisturizing electric control valve is also connected with pond of cooling tower liquid level gauge, and pond of cooling tower liquid level gauge, moisturizing electric control valve are all connected with control system, moisturizing thermometer is connected with moisturizing conductivity meter, and moisturizing conductivity meter is also connected with control system.

Described blow-off line is provided with water circulating pump, and recirculated water delivery side of pump is divided into two-way, a road is connected with Circulating water effluent electric control valve, and another road is connected with cooling tower.

Blowdown flow meter is provided with between described circulating water temperature meter and blowdown electric control valve.

Described inlet channel is provided with refill flow meter.

A kind of method controlling Open recirling cooling water system concentration rate, aperture and the pond of cooling tower liquid level gauge of moisturizing electric control valve are interlocked, when cooling tower liquid level is lower than the aperture increasing moisturizing electric control valve during setting value, when cooling tower liquid level is higher than the aperture reducing moisturizing electric control valve during setting value;

The data gathering moisturizing conductivity meter and moisturizing thermometer obtain moisturizing salt content S by control system _mend, the data gathering recirculated water conductivity meter and moisturizing thermometer obtain recirculated water salt content S by control system _follow, S _followwith S _mendratio N be concentration rate;

Aperture and the concentration rate N of blowdown electric control valve interlock, and when concentration rate N is greater than setting value, increases blowdown motorized adjustment valve opening, increase blowdown flow rate; When concentration rate N is less than setting value, reduces blowdown motorized adjustment valve opening, reduce blowdown flow rate, realize the automatic control to concentration rate N.

When moisturizing or recirculated water conductivity are less than 1200 μ s/cm, then moisturizing or recirculated water salt content $S=0.8382e^{(0.0001828t^2-0.03200t)}{K}^{1.0809};$

When moisturizing or recirculated water conductivity are greater than 1500 μ s/cm, then moisturizing or recirculated water salt content $S=0.5736e^{(0.0002281t^2-0.03322t)}{K}^{1.0713};$

In all the other situations, moisturizing or recirculated water salt content $S=0.4381e^{(0.0001800t^2-0.03206t)}{K}^{1.1351};$

Wherein e is constant, and K is moisturizing conductivity or recirculated water conductivity, and t is the temperature of moisturizing or recirculated water.

Compared with prior art, the beneficial effect that has of the present invention:

Owing to arranging recirculated water conductivity meter and circulating water temperature meter in system of the present invention, be connected with control system, pond of cooling tower liquid level gauge, moisturizing electric control valve are all connected with control system, moisturizing thermometer is connected with control system with moisturizing conductivity meter, the moisturizing motorized adjustment valve opening of recirculated water is regulated automatically according to the liquid level of pond of cooling tower, when the low liquid level of pond of cooling tower, the aperture of moisturizing electric control valve is increased by automatically appropriate after control system PID calculating, when pond of cooling tower high liquid level, the aperture of moisturizing electric control valve is reduced by automatically appropriate after control system PID calculating, make the level stability of pond of cooling tower within the specific limits, achieve the continuous autostable moisturizing of cooling tower, decrease the concentration rate fluctuation that uncontinuity moisturizing causes.The control system adopted can require to arrange according to the operational factor of different Open recirling cooling water system, has good widespread use; This system automation degree is high, greatly reduces the manual operation workload of operations staff.

Further, refill flow meter and blowdown flow meter can realize the on-line monitoring to rate of water make-up and blowdown flow rate.

In the present invention in control system method, the data gathering moisturizing conductivity meter and moisturizing thermometer obtain moisturizing salt content S by control system _mend, the data gathering recirculated water conductivity meter and moisturizing thermometer obtain recirculated water salt content S by control system _follow, S _followwith S _mendratio N be concentration rate; Visible the present invention can automatically according to the S calculating gained _followwith S _mendratio determination concentration rate N, thus greatly reduce the working strength of operations staff's labor measurement concentration rate, achieve the continuous real-time monitoring of recirculated water concentration rate.The concentration rate numerical value calculating gained by blowdown motorized adjustment valve opening and control system in the present invention is interlocked, when calculating gained operation concentration rate and being greater than setting value, increase the aperture of blowdown electric control valve, when calculating gained concentration rate and being less than setting value, reduce the aperture of blowdown electric control valve, thus achieve the automatic continuous blowdown of recirculating cooling water system.By Automatic continuous stably moisturizing and blowdown, the present invention can reduce the concentration rate fluctuation because the moisturizing of recirculated water discontinuity and blowdown cause greatly, recirculated water concentration rate is controlled within the scope of setting value ± 0.5, thus stabilize circulating water quality, ensure that the security of operation of circulation, decrease water amount of blowdown and amount of makeup water simultaneously, have significant water-saving result.The present invention can realize Automatic continuous stably moisturizing and the blowdown of Open recirling cooling water system, Automatic continuous on-line monitoring is realized to recirculated water concentration rate, the concentration rate fluctuation because the intermittent moisturizing of circulation and blowdown cause can be avoided, ensure that recirculated water runs concentration rate within the scope of setting concentration rate ± 0.5, thus stabilize circulating water quality, reduce the corrosion and scaling risk of circulation, ensure recirculating cooling water system safe and stable operation; And the Circulating water effluent water yield and amount of makeup water can be reduced, have significant water-saving result

Accompanying drawing explanation

Fig. 1 is structural representation of the present invention.

Fig. 2 adopts method of the present invention to contrast figure with the concentration rate variation tendency of conventional method for discharging pollution.

In figure, 1-cooling tower, 2-pond of cooling tower, 3-water circulating pump, 4-moisturizing electric control valve, 5-blowdown electric control valve, 6-refill flow meter, 7-blowdown flow meter, 8-moisturizing conductivity meter, 9-recirculated water conductivity meter, 10-pond of cooling tower liquid level gauge, 11-moisturizing thermometer, 12-circulating water temperature meter, 13-control system; M-circulating cooling make-up water, E-vaporization loss, D-windage loss, B-blowdown is lost.

Embodiment

Below in conjunction with accompanying drawing, the present invention is described in further detail.

See Fig. 1, control a system for Open recirling cooling water system concentration rate, comprise cooling tower 1, pond of cooling tower 2, water circulating pump 3, moisturizing electric control valve 4, blowdown electric control valve 5, refill flow meter 6, blowdown flow meter 7, moisturizing conductivity meter 8, recirculated water conductivity meter 9, pond of cooling tower liquid level gauge 10, moisturizing thermometer 11, circulating water temperature meter 12 and control system 13.

Wherein, below described cooling tower 1, pond of cooling tower 2 is set, pond of cooling tower 2 is arranged pond of cooling tower liquid level gauge 10, be provided with bottom pond of cooling tower 2 for blow-off line, this blow-off line is provided with water circulating pump 3, recirculated water conductivity meter 9, circulating water temperature meter 12 and blowdown electric control valve 5, between circulating water temperature meter 12 and blowdown electric control valve 5, is provided with blowdown flow meter 7.Recirculated water conductivity meter 9 is all connected with control system 13 with circulating water temperature meter 12; The outlet of described water circulating pump 3 is divided into two-way, and a road is connected with Circulating water effluent electric control valve 5, and another road is connected with cooling tower 1.

Also be provided with for the pipeline of pond of cooling tower supplementing water above pond of cooling tower 2, this pipeline is provided with moisturizing conductivity meter 8, moisturizing electric control valve 4, moisturizing thermometer 11 and refill flow meter 6, moisturizing electric control valve 4 is also connected with pond of cooling tower liquid level gauge 10, and pond of cooling tower liquid level gauge 10, moisturizing electric control valve 4 are all connected with control system 13, moisturizing thermometer 11 is all connected with control system 13 with moisturizing conductivity meter 8.

Wherein, aperture and the pond of cooling tower liquid level gauge 10 of moisturizing electric control valve 4 are interlocked, when cooling tower liquid level is lower than the aperture increasing moisturizing electric control valve 4 during setting value, when cooling tower liquid level is higher than the aperture reducing moisturizing electric control valve 4 during setting value.The data gathering moisturizing conductivity meter 8 and moisturizing thermometer 11 obtain moisturizing salt content S by control system 13 _mend, the data gathering recirculated water conductivity meter 9 and moisturizing thermometer 12 obtain recirculated water salt content S by control system 13 _follow, S _followwith S _mendratio N be operation concentration rate.

Salt content in water generally cannot on-line determination, but conductance and temperature all can measure online, and there is certain quantitative relationship with salt content in water.Control system set by this system can by the circulating cooling make-up water of on-line measurement gained and circulation electrical conductivity of water K _mendwith K _followand temperature T _mendwith T _followbe converted into the salt content S of circulating cooling make-up water and recirculated water _mendwith S _follow, its computing formula is:

When moisturizing or recirculated water conductivity are less than 1200 μ s/cm, then moisturizing or recirculated water salt content $S=0.8382e^{(0.0001828t^2-0.03200t)}{K}^{1.0809}$

When moisturizing or recirculated water conductivity are greater than 1500 μ s/cm, then moisturizing or recirculated water salt content $S=0.5736e^{(0.0002281t^2-0.03322t)}{K}^{1.0713};$

In all the other situations, moisturizing or recirculated water salt content $S=0.4381e^{(0.0001800t^2-0.03206t)}{K}^{1.1351};$

Wherein e is constant, and K is moisturizing conductivity or recirculated water conductivity, and t is the temperature of moisturizing or recirculated water.

The aperture of blowdown electric control valve 5 is interlocked with operation concentration rate N, when running concentration rate N and being greater than setting value, increases blowdown electric control valve 5 aperture, increases blowdown flow rate; When running concentration rate N and being less than setting value, reduce blowdown electric control valve 5 aperture, reduce blowdown flow rate.Refill flow meter 6 and blowdown flow meter 7 can realize the on-line monitoring to rate of water make-up and blowdown flow rate.

The water that in the present invention, inlet channel adds in pond of cooling tower 2 is circulating cooling make-up water M, and cooling tower 1, under evaporation wind, also exists vaporization loss E and vaporization loss D, there is blowdown loss B during blow-off line effluent sewerage.

The method controlling Open recirling cooling water system concentration rate is: aperture and the pond of cooling tower liquid level gauge of moisturizing electric control valve are interlocked, when cooling tower liquid level is lower than the aperture increasing moisturizing electric control valve during setting value, when cooling tower liquid level is higher than the aperture reducing moisturizing electric control valve during setting value;

The data gathering moisturizing conductivity meter and moisturizing thermometer obtain moisturizing salt content S by control system _mend, the data gathering recirculated water conductivity meter and moisturizing thermometer obtain recirculated water salt content S by control system _follow, S _followwith S _mendratio N be concentration rate;

Aperture and the concentration rate N of blowdown electric control valve interlock, and when concentration rate N is greater than setting value, increases blowdown motorized adjustment valve opening, increase blowdown flow rate; When concentration rate N is less than setting value, reduces blowdown motorized adjustment valve opening, reduce blowdown flow rate, realize the automatic control to concentration rate N.

Be described below by an instantiation.

Certain thermal power plant 1# unit is 300MW Thermal generation unit, its recirculated water adopts the circulation cooling water system of open pattern, former concentration rate is by operations staff's results of regular determination, and carry out adjust operation concentration rate by the mode of manual control water amount of blowdown and rate of water make-up, the concentration rate fluctuation of unit is comparatively large, and circulating water quality is unstable.

This unit have employed of the present invention a kind of can after the system and method for stability contorting recirculated water concentration rate, the aperture of its moisturizing electric control valve 4 regulates according to pond of cooling tower liquid level gauge 10, aperture is increased during low liquid level, reduce aperture during high liquid level, ensure that the liquid level of pond of cooling tower remains on setting range.By the on-line checkingi to moisturizing conductivity 8, moisturizing thermometer 11, recirculated water conductivity 9 and circulating water temperature 12, the recirculated water that can be calculated automatically and continuously by control system 13 runs concentration rate value N.Circulating water effluent electric adjustable section door 5 aperture and recirculated water run concentration rate N and interlock, when running concentration rate and being greater than setting value, increase the aperture of blowdown electric control valve 5, when running concentration rate and being less than setting value, reduce the aperture of blowdown electric control valve 5, thus realize automatic water supplement and the blowdown of recirculated water.The concentration rate of recirculated water can accurately control in the scope of setting value ± 0.5 by this system simultaneously.

Fig. 2 is the variation tendency of 1# unit recirculated water concentration rate before and after this system of application.As can be seen from Figure 2, the scope that concentration rate can control in setting value ± 0.5 by system of the present invention is accurately applied.

The present invention has the following advantages:

1) the present invention proposes a kind of system and method for stability contorting recirculating cooling water system concentration rate, the Automatic continuous stably moisturizing of Open recirling cooling water system can be realized by the method;

2) the present invention proposes a kind of system and method for stability contorting recirculating cooling water system concentration rate, Automatic continuous on-line monitoring can be realized to recirculated water concentration rate by the method;

3) the present invention proposes a kind of system and method for stability contorting recirculating cooling water system concentration rate, the stably blowdown of circulation Automatic continuous can be realized by the method;

4) the present invention proposes a kind of system and method for stability contorting recirculating cooling water system concentration rate, the concentration rate fluctuation because the intermittent moisturizing of circulation and blowdown cause can be avoided by the method, ensure that recirculated water runs concentration rate within the scope of setting concentration rate ± 0.5, thus stabilize circulating water quality, ensure that the security of operation of circulation;

5) the present invention proposes a kind of system and method for stability contorting recirculating cooling water system concentration rate, the Circulating water effluent water yield and amount of makeup water can be reduced by the method, have significant water-saving result;

6) the present invention proposes a kind of system and method for stability contorting recirculating cooling water system concentration rate, automaticity is high, control system wherein can require to arrange according to the operational factor of different open type circulation, has good widespread use.Circulating water system amount has effectively been saved after adopting the method, stabilize circulating water quality, reduce the corrosion and scaling risk of circulation, ensured recirculating cooling water system safe and stable operation, decrease the workload of operations staff simultaneously, have a good application prospect.

Claims (6)

1. one kind controls the system of Open recirling cooling water system concentration rate, it is characterized in that, comprise control system and cooling tower (1), described cooling tower (1) below is provided with the pond of cooling tower (2) with pond of cooling tower liquid level gauge (10), pond of cooling tower (2) bottom is provided with blow-off line, blow-off line is provided with recirculated water conductivity meter (9), circulating water temperature meter (12) and blowdown electric control valve (5); Recirculated water conductivity meter (9) is all connected with control system (13) with circulating water temperature meter (12);

Pond of cooling tower (2) top is provided with for the inlet channel of pond of cooling tower supplementing water, inlet channel is provided with moisturizing conductivity meter (8), moisturizing electric control valve (4) and moisturizing thermometer (11), moisturizing electric control valve (4) is also connected with pond of cooling tower liquid level gauge (10), and pond of cooling tower liquid level gauge (10), moisturizing electric control valve (4) are all connected with control system (13), moisturizing thermometer (11) is all connected with control system (13) with moisturizing conductivity meter (8).

2. a kind of system controlling Open recirling cooling water system concentration rate according to claim 1, it is characterized in that, described blow-off line is provided with water circulating pump (3), and the outlet of water circulating pump (3) is divided into two-way, one tunnel is connected with Circulating water effluent electric control valve (5), and another road is connected with cooling tower (1).

3. a kind of system controlling Open recirling cooling water system concentration rate according to claim 1, it is characterized in that, between described circulating water temperature meter (12) and blowdown electric control valve (5), be provided with blowdown flow meter (7).

4. a kind of system controlling Open recirling cooling water system concentration rate according to claim 1, is characterized in that, described inlet channel is provided with refill flow meter (6).

5. one kind controls the method for Open recirling cooling water system concentration rate, it is characterized in that, aperture and the pond of cooling tower liquid level gauge (10) of moisturizing electric control valve (4) are interlocked, when cooling tower liquid level is lower than the aperture increasing moisturizing electric control valve (4) during setting value, when cooling tower liquid level is higher than the aperture reducing moisturizing electric control valve (4) during setting value;

The data gathering moisturizing conductivity meter (8) and moisturizing thermometer (11) obtain moisturizing salt content S by control system (13) _mend, the data gathering recirculated water conductivity meter (9) and moisturizing thermometer (12) obtain recirculated water salt content S by control system _follow, S _followwith S _mendratio N be concentration rate;

Aperture and the concentration rate N of blowdown electric control valve (5) interlock, and when concentration rate N is greater than setting value, increase blowdown electric control valve (5) aperture, increase blowdown flow rate; When concentration rate N is less than setting value, reduce blowdown electric control valve (5) aperture, reduce blowdown flow rate, realize the automatic control to concentration rate N.

6. the method controlling Open recirling cooling water system concentration rate as claimed in claim 5, is characterized in that,

When moisturizing or recirculated water conductivity are less than 1200 μ s/cm, then moisturizing or recirculated water salt content $S=0.8382e^{(0.0001828t^2-0.03200t)}{K}^{1.0809};$

When moisturizing or recirculated water conductivity are greater than 1500 μ s/cm, then moisturizing or recirculated water salt content $S=0.5736e^{(0.0002281t^2-0.03322t)}{K}^{1.0713};$

In all the other situations, moisturizing or recirculated water salt content $S=0.4381e^{(0.0001800t^2-0.03206t)}{K}^{1.1351};$

Wherein e is constant, and K is moisturizing conductivity or recirculated water conductivity, and t is the temperature of moisturizing or recirculated water.