The method and the concentration rate instrument that are used for Control Circulation chilled water cycles of concentration
Technical field
The present invention relates to a kind of system that is used for Control Circulation chilled water cycles of concentration, relate in particular to a kind of system that comes Control Circulation chilled water cycles of concentration by the multiple of measuring the increase of fluorescent tracing agent concentration.
Background technology
Concentration rate of circulating cooling water refers to the content of certain material in chilled water and the ratio of content in moisturizing, also can be expressed as the ratio of cooling water replenishment total amount and total amount of pollutants discharged (comprise blowdown, leakage is splashed etc.).
Recirculating cooling water system is in operation, by the evaporation section chilled water to reach the purpose of cooling.Because evaporation is pure water, the mineral matter that contains in the chilled water that is evaporated continues to stay in the chilled water, and this causes chilled water mineral concentration constantly to raise.When the concentration of chilled water mineral reaches certain proportion, must the discharge unit chilled water avoiding fouling, burn into deposition and microorganism a series of problems such as multiply.The amount decision cycles of concentration of discharging chilled water, the amount of discharging greatly then cycles of concentration is low, otherwise, the little then cycles of concentration of the amount height of discharging chilled water.
In China's process water 70~80% is the recirculated cooling water moisturizing, the National Standard Code for design of industrial recirculating cooling water treatment " the recirculated water cycles of concentration is brought up to 5 times from average 3 times (nineteen ninety-five standards) among the GB50050-2007, its water-saving result can improve 0.4 percentage point, in water consumption in 2004,17,600,000,000 tons of water can be saved in the whole nation.In addition, the indirect benefit that also has is to reduce water source scale and water distributing network, reduces the water treatment agent amount, reduces kinetic energy consumption etc.Therefore, accurately, fast, online the recirculated water cycles of concentration being controlled in the reasonable range is to realize water-saving and emission-reducing, one of important step in the protection environment.
At present, Control Circulation cooling water system cycles of concentration mainly contains following method:
(1) fluid level controller: mainly enter the rate of water make-up of cooling water system and the water of outflow system is that blowdown flow rate is finished by control.The method is the control system rate of water make-up accurately, and as using fluid level controller in chilled water cistern or tower basin, when water level is lower than the fluid level controller setting value, water compensating valve just brings into operation.But be difficult to the control system blowdown flow rate, particularly occur leaking when system, overflow or when splashing, blowdown flow rate is uncontrollable just, cycles of concentration is just uncontrollable.
(2) conductivity meter: using conductivity control blowdown is the typical method of control cycles of concentration.Its principle is, owing to have ionic species in the water, makes glassware for drinking water that electric conductivity be arranged, and its electrical conductivity can be measured, is conductivity.When the increase of chilled water intermediate ion concentration, its conductivity also increases, and the multiple of its increase is approximately equal to the chilled water cycles of concentration.So can set a fixedly conductivity value, when the chilled water conductivity reaches this fixed value, begin blowdown.When using conductivity meter control cycles of concentration, when system water supplement changes, perhaps chilled water uses a plurality of moisturizings water source, and conductivity meter just can not accurately be controlled cycles of concentration.If in water treatment, add chemicals such as acid, germifuge etc., the remarkable rising chilled water conductivity of meeting causes blowdown flow rate to increase, and cycles of concentration reduces; Thereby cause chilled water to cross circulation if problems such as system's generation fouling can reduce the chilled water conductivity, will cause water treatment " heavy failure ".
(3) timer: use time of timer control system blowdown and any specific material in the not actual measurement water.Timer can only be similar to by the control blowdown flow rate and control cycles of concentration, but when the variation of cooling water system evaporation capacity, environment temperature, humidity change, and cycles of concentration will be changed.
It is directly to measure cycles of concentration accurately, online that the method for above-mentioned several Control Circulation cooling water system cycles of concentration all exists a critical technical problems, and according to this cycles of concentration control blowdown.
Summary of the invention
At above-mentioned prior art, the invention provides a kind of method that is used for Control Circulation chilled water cycles of concentration, this control method can be measured the cycles of concentration of Control Circulation water directly, accurately, fast, online.
In order to solve the problems of the technologies described above, the present invention is used for the technical scheme that the method for Control Circulation chilled water cycles of concentration is achieved and is: come Control Circulation water cycles of concentration according to the fluorescent tracer concentration change, its step is as follows:
Step 1, to add concentration in the recirculated cooling water moisturizing be the fluorescent tracer of 0.01ppm-1ppm;
Step 2, use one first photofluorometer, the concentration of fluorescent tracer described in the moisturizing of on-line measurement recirculated cooling water, and, meet above-mentioned concentration requirement in order to guarantee the fluorescent tracer that in the recirculated cooling water moisturizing, is added by the automatic dosing pump of regulating of a concentration rate instrument controller;
Step 3, use one second photofluorometer, the concentration of the fluorescent tracer in the on-line measurement recirculated cooling water;
Step 4, according to the measured value of above-mentioned second photofluorometer and first photofluorometer, draw in the recirculated water cycles of concentration=recirculated cooling water of current state fluorescent tracing agent concentration in fluorescent tracing agent concentration/recirculated cooling water moisturizing;
Step 5, the above-mentioned concentration rate instrument controller of use are controlled a chilled water blowdown motorized valve, when the recirculated water cycles of concentration reaches setting value, and the operation of blowdown motorized valve, chilled water blowdown; Otherwise, return above-mentioned steps two.
The present invention is used for the concentration rate instrument of recirculating cooling water system, comprising: one is used for the chemicals dosing plant to recirculated cooling water fluorescent tracer that moisturizing adds; One is used for first photofluorometer of on-line measurement recirculated cooling water moisturizing fluorescent tracing agent concentration; One is used for second photofluorometer of on-line measurement recirculated cooling water fluorescent tracing agent concentration; One is used for the concentration rate instrument controller of computation cycles chilled water cycles of concentration, includes at least in the described concentration rate instrument controller: the PID computing module that is used for on-line automatic control chemicals dosing plant; Two analog quantity load modules that receive above-mentioned two photofluorometer data respectively; Be used to control the switching value output module of blowdown apparatus operation.
Compared with prior art, the invention has the beneficial effects as follows:
Control system of the present invention is to come Control Circulation water cycles of concentration according to the variation of adding fluorescent tracing agent concentration in the recirculated cooling water moisturizing to, be provided with two online concentration that record fluorescent tracer in moisturizing and the recirculated water of photofluorometer, and adopt concentration rate instrument controller to compare, can measure the cycles of concentration of recirculated cooling water directly, accurately, online, and according to this cycles of concentration control blowdown.
Description of drawings
Fig. 1 is the artwork that the present invention is used for Control Circulation chilled water cycles of concentration;
Fig. 2 is the recirculating cooling water system cycles of concentration control block diagram that has concentration rate instrument of the present invention.
Among the figure: 1. fluorescent tracer, 2. dosing pump, 3. water charging system, 4. first photofluorometer, 5. second photofluorometer, 6. concentration rate instrument controller, 7. process heat exchange system, 8. blowdown apparatus, 9. ebullator, 10 cooling towers.
Embodiment
Below in conjunction with the drawings and specific embodiments the present invention is done to describe in further detail.
As shown in Figure 1, the present invention's concentration rate instrument of being used for recirculating cooling water system comprises: one is used for the chemicals dosing plant 2 to recirculated cooling water moisturizing 3 fluorescent tracer that adds 1; One is used for first photofluorometer 4 of on-line measurement recirculated cooling water moisturizing 3 fluorescent tracing agent concentrations; One is used for second photofluorometer 5 of on-line measurement recirculated cooling water fluorescent tracing agent concentration; One is used to calculate the concentration rate instrument controller 6 with Control Circulation chilled water cycles of concentration,
As shown in Figure 2, include the PID computing module 23 that is used to control on-line automatic control chemicals dosing plant at least in the described concentration rate instrument controller 6; Two analog quantity load modules 24,26 that receive above-mentioned two photofluorometer data respectively; Be used to control the switching value output module 28 of blowdown apparatus 8 operations.
The method that the present invention is used for Control Circulation chilled water cycles of concentration is to come Control Circulation water cycles of concentration according to the fluorescent tracer concentration change, its recirculating cooling water system comprises ebullator 9, cooling tower 10, process heat exchange system 7, water charging system 3 and blowdown apparatus 8 at least, first photofluorometer 4 and second photofluorometer 5 and concentration rate instrument controller 6 are connected in the above-mentioned recirculating cooling water system, and the technological process of control cycles of concentration is as follows:
Step 1, to add concentration in recirculated cooling water moisturizing 3 be 0.01ppm-1ppm (1ppm=0.001 ‰'s) fluorescent tracer 1;
Step 2, use first photofluorometer 4, the concentration of fluorescent tracer 1 described in the moisturizing 3 of on-line measurement recirculated cooling water, and, meet above-mentioned concentration requirement in order to guarantee the fluorescent tracer 1 that in recirculated cooling water moisturizing 3, is added by the concentration rate instrument controller 6 automatic dosing pumps 2 of regulating;
Step 3, use second photofluorometer 5, the concentration of the fluorescent tracer in the on-line measurement recirculated cooling water;
Step 4, according to the measured value of above-mentioned second photofluorometer 5 and first photofluorometer 4, draw in the recirculated water cycles of concentration=recirculated cooling water of current state fluorescent tracing agent concentration in fluorescent tracing agent concentration/recirculated cooling water moisturizing;
Step 5, the motorized valve that uses above-mentioned concentration rate instrument controller 6 to control in the chilled water blowdown apparatus 8, when the recirculated water cycles of concentration reaches setting value, the operation of blowdown motorized valve, chilled water blowdown; Otherwise, return above-mentioned steps two.
The course of work of concentration rate instrument of the present invention is:
Fluorescent tracer 1 adds in the cooling water system moisturizing 3 by variable ratio frequency changer dosing pump 2.
The concentration of fluorescent tracer detects in 4 pairs of moisturizings of first photofluorometer, transfers concentration signal to analog quantity electric signal (4-20mA), and signal is passed to analog quantity load module 24.
Concentration rate instrument controller 6 carries out PID computing 23 according to fluorescent tracer setting value 22 and by the data that analog quantity load module 24 is gathered; Then, regulate to frequency conversion dosing pump 2 by analog output module 21 output analog signalses and to add dose, make that the fluorescent tracing agent concentration reaches tracer agent setting value 22 in the moisturizing.
The concentration of fluorescent tracer detects in 5 pairs of chilled waters of second photofluorometer, transfers concentration signal to analog quantity electric signal (4-20mA), and signal is passed to analog quantity load module 26.
The data that concentration rate instrument controller 6 is gathered analog quantity load module 24, data and the cycles of concentration setting value 25 that analog quantity load module 26 is gathered compare computing 27, when the data ratio (being the recirculated water cycles of concentration of current state) that data of being gathered when analog quantity load module 24 and analog quantity load module 26 are gathered surpasses cycles of concentration setting value 25, concentration rate instrument controller 6 is by switching value output module 28 operation blowdown apparatus 8, and cooling water system begins blowdown.How to judge whether its blowdown finishes, can adopt two kinds of control modes, that is: finish by selecting blowing time length or cycles of concentration lower limit to control blowdown.
Although top invention has been described in conjunction with figure; but the present invention is not limited to above-mentioned embodiment; above-mentioned embodiment only is schematic; rather than it is restrictive; those of ordinary skill in the art is under enlightenment of the present invention; under the situation that does not break away from aim of the present invention, can also make a lot of distortion, these all belong within the protection of the present invention.