CN101311123B - Recirculated cooling water system cascade use method - Google Patents

Abstract

The invention provides a cascade application method for a circulating cooling water system, which comprises that two or more than two circulating water systems are in cascade use, and condensation time of each circulating water system in a cascade chain runs according to the sequence from low to high; the water drainage of a former circulating water system is directly used as the make-up water ofthe next circulating water system, and the water drainage of the last circulating water system is directly drained out. When N circulating water systems are used in cascade, the calculating formula ofthe concentration time in the Kth circulating water system in the cascade chain is the formula on the right; only the last circulating water system among the N circulating water systems by adopting the method of the invention has high condensation time, bad water quality and large processing difficulty, while other circulating water systems have comparatively low condensation time, comparativelygood water quality and easy treatment, thereby ensuring water treatment effect.

Description

The recirculated cooling water system cascade using method

Technical field

The present invention relates to the treatment process that a plurality of recirculated cooling water system cascades use, belong to recirculated cooling water treatment process field.

Background technology

Water coolant is the indispensable general facilities of industrial enterprise, is the water rich and influential family.To recycle after the treatment of cooling water, can satisfy technological process to the water treatment effect of requirement on the one hand, assurance production equipment long period is normally moved; Save service water on the other hand more than 98%; reduce the blowdown of bigger quantity; to protection water resources, protection water surrounding, reducing production costs has huge benefit, thereby obtains people's extensive attention, thereby promoted the fast development and the widespread use of recirculated cooling water technology.

Along with aggravation, the water environment pollution of water resources disparities between supply and demand is on the rise and the raising of circulating water treatment technology level, people adopt the method that improves the recirculated water cycles of concentration to realize the recirculating cooling water system water saving usually and reduce water amount of blowdown.But, raising along with cycles of concentration, fouling tendency ion such as calcium ion, magnesium ion concentration in the recirculated water, with promote corrosive ion such as chlorion, sulfate ion concentration to be multiplied, make the water quality variation, the fouling tendency of water quality and corrodibility strengthen, thereby cause the increase of water treatment difficulty, effect to descend, and produce the contradiction between water saving and the water treatment effect.And in enterprises such as large-scale oil refining, chemical industry, metallurgy and thermoelectricity, generally be provided with a plurality of recirculating cooling water systems and provide recirculated cooling water for different production equipments.At present, these circulating water systems all adopt the independent operating mode to move, i.e. each circulating water system moisturizing alone of enterprise, blowdown alone, move under a certain cycles of concentration alone.Enterprise is in order to realize water saving target, often all circulating water systems all are controlled at than high concentration multiple operation down, cause all circulating water systems all to adopt relatively poor water quality, cause all circulating water system intractabilities all to increase, make treatment effect be difficult to guarantee.

CN1463926A discloses a kind of heat-engine plant circulating water classification concentration series use technology, the cycles of concentration of first step recirculated cooling water≤2, the cycles of concentration of second stage recirculated cooling water≤4.5, and will filter and the weak acid ion exchange treatment through the sewage that the first step concentrate to be discharged.

Summary of the invention

The objective of the invention is to propose a kind of method that helps guaranteeing most of circulating water system treatment effects to having the enterprise of two or more circulating water systems.

The tandem using method of the recirculating cooling water system that the present invention proposes comprises: two or more circulating water system tandems are used, the cycles of concentration of each circulating water system in the daisy chain moves according to order from low to high, and the cycles of concentration of last step circulating water system is the highest.The draining of previous circulating water system is directly as the make up water of next circulating water system, and the draining of last circulating water system is directly outer puts.

The cycles of concentration calculation formula of K circulating water system in the daisy chain is as follows:

$n_N>n_K\&GreaterEqual;\frac{(n_N-1)({\mathrm{<figure-callout\; id="1"\; label="E"\; filenames="H2007100995664E00012.png"\; state="\{\{state\}\}">E</figure-callout>}}_1+E_2+E_3+......+E_K)}{{\mathrm{<figure-callout\; id="1"\; label="E"\; filenames="H2007100995664E00012.png"\; state="\{\{state\}\}">E</figure-callout>}}_1+E_2+E_3+......+E_N}+1$

Wherein: N＞K 〉=1.n _NCycles of concentration when being last circulating water system series operation, the highest cycles of concentration when equaling a plurality of circulating water system isolated operation.E represents evaporated water, the m of unit ³/ h.

When the quantity of circulating water of system and the exit port temperature difference were determined, the steam output of system can calculate by following formula:

$E=\frac{R\&times;\mathrm{\&Delta;t}}{580}$

In the formula, R represents quantity of circulating water, the m of unit ³/ h; Δ t expresses the import temperature difference, unit ℃.The quantity of circulating water of system and the temperature difference can read at the scene.The evaporated water of first system may be different with N system's evaporated water, and this will be decided by the quantity of circulating water of circulating water system and the temperature difference of recirculated water turnover water cooling tower.

When the series connection of a plurality of systems is used, the sewer of last system directly as a supplement water enter in the next system, medicament in the sewer has also entered into next system so, in order to guarantee that water treatment agent is in the finite concentration scope in the circulating water system, the blowdown flow rate of previous system should be less than the blowdown flow rate of next system, so cycles of concentration has certain scope.

The cycles of concentration of K circulating water system in daisy chain calculates according to following formula:

$n_K=\frac{(n_N-1)({\mathrm{<figure-callout\; id="1"\; label="E"\; filenames="H2007100995664E00012.png"\; state="\{\{state\}\}">E</figure-callout>}}_1+E_2+E_3+......+E_K)}{{\mathrm{<figure-callout\; id="1"\; label="E"\; filenames="H2007100995664E00012.png"\; state="\{\{state\}\}">E</figure-callout>}}_1+E_2+E_3+......+E_N}+1$

Only need to add medicament in first step circulating water system, other circulating water systems need not add medicament again, and the draining of previous circulating water system need not carry out purifying treatment, and are directly as the make up water of next circulating water system, simple to operation.

When the cycles of concentration of K circulating water system in following formula computer capacity:

$n_N>n_K>\frac{(n_N-1)({\mathrm{<figure-callout\; id="1"\; label="E"\; filenames="H2007100995664E00012.png"\; state="\{\{state\}\}">E</figure-callout>}}_1+E_2+E_3+......+E_K)}{{\mathrm{<figure-callout\; id="1"\; label="E"\; filenames="H2007100995664E00012.png"\; state="\{\{state\}\}">E</figure-callout>}}_1+E_2+E_3+...+E_N}+1$

Each circulating water system in the daisy chain need be added a certain amount of water and medicament, guarantees the normal operation of circulating water system.

Said water treatment agent can be the corrosion-mitigation scale-inhibition recombiner with inhibition and scale inhibition effect, preferably has organic phosphonates, phosphine carboxylate salt, zinc salt and contains the polycarboxylic acid polymkeric substance of AMPS.

The present invention has following characteristics:

The recirculating cooling water system of a.N identical cycles of concentration independent operating adopts method operation of the present invention, and the moisturizing total amount is identical with N recirculating cooling water system independent operating with the medicament total amount.

The circulating water system of b.N different cycles of concentration independent operatings adopts method operation of the present invention, and moisturizing total amount and medicament total amount all are less than the moisturizing total amount and the medicament total amount of N recirculated cooling water independent operating.

C.N recirculating cooling water system adopts method operation of the present invention, have only the cycles of concentration of last circulating water system higher, water quality is relatively poor, intractability is bigger, and the cycles of concentration of other several cycles water systems is all lower, water quality is better, and processing is easier to, thereby makes the water treatment effect more guaranteed.

Description of drawings

Material balance figure during Fig. 1 N system independent operating in parallel.

Material balance figure during Fig. 2 N system series operation.

Embodiment

Specifically, to having the enterprise of two or more circulating water systems, a plurality of circulating water system tandems are used, the cycles of concentration of each circulating water system in the daisy chain is according to order operation from low to high, be that foremost first concentration multiple of circulating water system is minimum in the daisy chain, its draining is as the make up water of second circulating water system, the draining of second circulating water system is as the make up water of the 3rd circulating water system, the rest may be inferred, last circulating water system in the daisy chain, cycles of concentration is the highest, and draining does not re-use, directly outer putting.This method is compared with several cycles water system independent operating method, total amount of makeup water, water displacement and reagent consumption amount are not higher than total rate of water make-up, water displacement and the reagent consumption amount of several cycles water system independent operating method, have only the cycles of concentration of last circulating water system the highest, water quality is the poorest, intractability is bigger, and the cycles of concentration of other several cycles water systems is all lower, and water quality is better, processing is easier to, thereby makes the water treatment effect more guaranteed.

Principle of the present invention is: when enterprise has independently recirculating cooling water system of N, the quantity of circulating water of each independent system is respectively R ₁, R ₂, R ₃... R _K... R _N, the exit port water temperature difference is Δ t ₁, Δ t ₂, Δ t ₃.... Δ t _K... Δ t _N, cycles of concentration is n ₀₁, n ₀₂, n ₀₃... n _0K... n _0N, the water conditioner working concentration is C, according to existing method, and each system's independent operating, the material balance figure of system is as shown in Figure 1.

When the quantity of circulating water of system and the exit port temperature difference were determined, the steam output of system can calculate by (1) formula:

$E=\frac{R\&times;\mathrm{\&Delta;t}}{580}...\left(1\right)$

E-evaporated water in the formula, m ³/ h

The R-quantity of circulating water, m ³/ h

The Δ t-exit port temperature difference, ℃

Can calculate the evaporated water E of each system according to formula (1) ₁, E ₂, E ₃... E _N, obtain total evaporation water yield E by the evaporated water of each system ₀, total water amount of blowdown B ₀, total rate of water make-up M ₀With water conditioner total amount consumed L ₀, that is:

E ₀＝E ₁+E ₂+E ₃+……+E _N

$B_0=\frac{E_1}{n_{01}-1}+\frac{E_2}{n_{02}-1}+\frac{E_3}{n_{03}-1}+...\frac{E_K}{n_{0K}-1}+...\frac{E_N}{n_{0N}-1}$

$M_0=E_0+B_0=({\mathrm{<figure-callout\; id="1"\; label="E"\; filenames="H2007100995664E00012.png"\; state="\{\{state\}\}">E</figure-callout>}}_1+E_2+...E_K+...+E_N)+(\frac{E_1}{n_{01}-1}+\frac{E_2}{n_{02}-1}+...\frac{E_K}{n_{0K}-1}+...+\frac{E_N}{n_{0N}-1})$

$L_0=C\&times;B_0=C(\frac{E_1}{n_{01}-1}+\frac{E_2}{n_{02}-1}+...+\frac{E_K}{n_{0K}-1}+...+\frac{E_N}{n_{0N}-1})$

Adopt the tandem using method when enterprise has the individual independently recirculating cooling water system of N, the cycles of concentration of first step circulating water system is n ₁, the cycles of concentration of second stage circulating water system is n ₂, the cycles of concentration of K level circulating water system is n _K, the cycles of concentration of last step N level circulating water system is n _NMaterial balance as shown in Figure 2 when (during a plurality of circulating water system independent operating the highest cycles of concentration), system series operation.

M ₁＝E ₁+B ₁

M ₁C ₀=B ₁CR ₁Obtain

B _K-1+M _K＝E _K+B _K

B _K-1n _K-1C ₀+ M _KC ₀=CR _KB _KObtain

The cycles of concentration calculation formula of each series connection using system is as follows:

$n_N>n_K\&GreaterEqual;\frac{(n_N-1)({\mathrm{<figure-callout\; id="1"\; label="E"\; filenames="H2007100995664E00012.png"\; state="\{\{state\}\}">E</figure-callout>}}_1+E_2+E_3+......+E_K)}{{\mathrm{<figure-callout\; id="1"\; label="E"\; filenames="H2007100995664E00012.png"\; state="\{\{state\}\}">E</figure-callout>}}_1+E_2+E_3+......E_N}+1...\left(2\right)$

According to above-mentioned material balance principle, the rate of water make-up and the blowdown flow rate of the 1st grade of circulating water system calculate according to following formula:

${\mathrm{<figure-callout\; id="1"\; label="B"\; filenames="H2007100995664E00012.png"\; state="\{\{state\}\}">B</figure-callout>}}_1=\frac{E_1}{n_1-1}...\left(3\right)$

${\mathrm{<figure-callout\; id="1"\; label="M"\; filenames="H2007100995664E00012.png"\; state="\{\{state\}\}">M</figure-callout>}}_1=\frac{n_1{E}_1}{n_1-1}...\left(4\right)$

E in the formula ₁, n ₁Can calculate by formula (1) and (2).

The rate of water make-up of K level circulating water system and blowdown flow rate (except the 1st grade of circulating water system) can calculate according to following formula:

$B_K=\frac{{\mathrm{<figure-callout\; id="1"\; label="E"\; filenames="H2007100995664E00012.png"\; state="\{\{state\}\}">E</figure-callout>}}_1+E_2+E_3+......+E_K}{n_N-1}...\left(5\right)$

$M_K=\frac{E_K{n}_K{n}_{K-1}+({\mathrm{<figure-callout\; id="1"\; label="E"\; filenames="H2007100995664E00012.png"\; state="\{\{state\}\}">E</figure-callout>}}_1+E_2+E_3+......+E_K)n_{K-1}-({\mathrm{<figure-callout\; id="1"\; label="E"\; filenames="H2007100995664E00012.png"\; state="\{\{state\}\}">E</figure-callout>}}_1+E_2+E_3+......+E_K)n_K}{(n_K-1)(n_{K-1}-1)}...\left(6\right)$

$E_K=\frac{R_K\&times;\mathrm{\&Delta;t}}{580}...\left(7\right)$

In the formula: M _KThe rate of water make-up of-Di K level system

E _KThe steam output of-Di K level system

R _KThe quantity of circulating water of-Di K level system can read by the situ metrology pump

B _KThe blowdown flow rate of-Di K level system

C ₀-make up water intermediate ion concentration

n _NThe cycles of concentration of-Di N level system (during N system independent operating the highest cycles of concentration)

According to the aforementioned calculation formula, when N circulating water system series operation, total evaporation water yield E ' ₀, total water amount of blowdown B ' ₀, total rate of water make-up M ' ₀With water conditioner total amount consumed L ' ₀, then:

E′ ₀＝E ₁+E ₂+E ₃+……+E _N

$B_0^{\&prime;}=B_N=\frac{{\mathrm{<figure-callout\; id="1"\; label="E"\; filenames="H2007100995664E00012.png"\; state="\{\{state\}\}">E</figure-callout>}}_1+E_2+E_3+......+E_N}{n_N-1}$

$M_0^{\&prime;}=E_0^{\&prime;}+B_0^{\&prime;}=\frac{n_N({\mathrm{<figure-callout\; id="1"\; label="E"\; filenames="H2007100995664E00012.png"\; state="\{\{state\}\}">E</figure-callout>}}_1+E_2+E_3+......+E_n)}{n_N-1}$

$L_0^{\&prime;}=C\&times;B_0^{\&prime;}=\frac{C({\mathrm{<figure-callout\; id="1"\; label="E"\; filenames="H2007100995664E00012.png"\; state="\{\{state\}\}">E</figure-callout>}}_1+E_2+E_3+...+E_n)}{n_N-1}$

Cycles of concentration is identical during N recirculating cooling water system independent operating, i.e. n ₀₁=n ₀₂=n ₀₃=...=n _0k=...=n _0N, adopt tandem operation and independent operating respectively, n ₀₁=n ₀₂=n ₀₃=...=n _0k=...=n _0N=n _N, the vaporize water total amount is constant, i.e. E ₀'=E ₀The draining total amount equates that last system's water displacement of i.e. tandem operation equals the water displacement sum of each system of independent operating; The moisturizing total amount equates, because total evaporation is identical respectively with total displacement; The medicament total amount equates, because the draining total amount equates.

Cycles of concentration difference during N recirculating cooling water system independent operating adopts the tandem operation, last step concentration multiple of circulating water system the highest cycles of concentration when being up to N circulating water system independent operating.Evaporated water is constant, i.e. E ₀'=E ₀The minimizing of draining total amount is the water displacement sum that last system's water displacement of tandem operation is less than each system of independent operating; Rate of water make-up reduces, because total evaporation is identical and total displacement reduces; The medicament total amount reduces, because water displacement reduces.

The present invention will be further described below by embodiment, but not thereby limiting the invention.

Embodiment 1

Experiment water quality adopts the on-the-spot water of Central Plains petrochemical industry, and general data is as shown in table 1.Data presentation in the table, on-the-spot water are high hard haline waters, belong to strong fouling tendency water quality.

Table 1 experiment water quality general data

Carry out dynamic simulation experiment according to 407 methods in China PetroChemical Corporation's " water coolant analysis and experimental technique ", the quantity of circulating water of system is 150L/h, and the temperature difference of turnover saliva is 10 ℃.On-the-spot water is regulated after the basicity make up water as dynamic simulation experiment with sulfuric acid.The not pre-film of test tube, in vitro water flow velocity is controlled at 0.8m/s, and inflow temperature is controlled at 32 ℃, and leaving water temperature(LWT) is controlled at 40 ℃～42 ℃, and cycles of concentration is controlled at 6.0 ± 0.2, adds the composite water disposal agent of 100mg/L in the system.

Employing is with two circulating water system series operations, and the cycles of concentration of the first step is controlled at 3.5 ± 0.2, and the cycles of concentration of second stage circulating water system is that 6.0 ± 0.2,15 days dynamic simulation experiment result is as shown in table 2.As can be seen from Table 2, the system handles effect that cycles of concentration is lower is better than the cycles of concentration higher system.

Table 2 dynamic simulation experiment result

Embodiment 2

The control condition of experiment water quality and circulating water system is with embodiment 1, with three circulating water system series operations, the cycles of concentration of first step circulating water system is controlled at 2.7 ± 0.2, the cycles of concentration of second stage circulating water system is controlled at 4.3 ± 0.2, the cycles of concentration of third stage circulating water system is controlled at 6.0 ± 0.2,15 days dynamic simulation experiment result such as table 3.Table 3 result shows that cycles of concentration is low more, and treatment effect is good more.

Table 3 dynamic simulation experiment result

Embodiment 3

The control condition of experiment water quality and circulating water system is with embodiment 1, with four circulating water system series operations, the cycles of concentration of first circulating water system is controlled at 2.3 ± 0.2, the cycles of concentration of second stage circulating water system is controlled at 3.5 ± 0.2, the cycles of concentration of third stage circulating water system is 4.8 ± 0.2, the cycles of concentration of fourth stage circulating water system is 6.0 ± 0.2,15 days dynamic simulation experiment result such as table 4.Table 4 is the result show, cycles of concentration is low more, and treatment effect is good more.

Table 4 dynamic simulation experiment result

Embodiment 4

The control condition of experiment water quality and circulating water system is with embodiment 1, with five circulating water system series operations, the cycles of concentration of first step circulating water system is controlled at 2.0 ± 0.2, the cycles of concentration of second stage circulating water system is controlled at 3.0 ± 0.2, the cycles of concentration of third stage circulating water system is controlled at 4.0 ± 0.2, the cycles of concentration of fourth stage circulating water system is controlled at 5.0 ± 0.2, the cycles of concentration of last step circulating water system is controlled at 6.0 ± 0.2,15 days dynamic simulation experiment result such as table 5.As can be seen from Table 5, the treatment effect of low cycles of concentration operational system water conditioner obviously is better than the system of high concentration multiple operation.

Table 5 dynamic simulation experiment result

Embodiment 5

Experiment water quality adopts the on-the-spot water in certain ethylene plant, and experiment water quality is as shown in table 6.From water quality data as can be seen, the chlorion of on-the-spot water and sulfate ion concentration are respectively 110.0mg/L and 113.3mg/L, and basicity and pH are lower, and these features show that it has severe corrosive.

Table 6 experiment water quality general data

Carry out dynamic simulation experiment according to 407 methods in China PetroChemical Corporation's " water coolant analysis and experimental technique ", the quantity of circulating water of system is 150L/h, and the temperature difference of turnover saliva is 10 ℃.On-the-spot water is adopted in experiment, and the experiment initial stage, the disposable sodium bicarbonate 120mg/L that adds was (with CaCO ₃Meter), experimental session is tested the basicity of water about 80mg/L with sodium bicarbonate control.The not pre-film of test tube, in vitro water flow velocity is controlled at 0.8m/s, and inflow temperature is controlled at 32 ℃, and leaving water temperature(LWT) is controlled at 40 ℃～42 ℃, and cycles of concentration is controlled at 6.0 ± 0.2, adds the composite water disposal agent of 100mg/L in the system.

Adopt two circulating water system series operations, the cycles of concentration scope of first step system is 3.5 ± 0.2, and the cycles of concentration of second stage circulating water system is that 6.0 ± 0.2,15 days dynamic simulation experiment result is as shown in table 7.Experimental result in the table 7 shows that the erosion rate of low cycles of concentration operational system test tube obviously reduces than the high concentration multiple operational system, and the treatment effect of water conditioner is better than the high concentration multiple operational system.

Table 7 dynamic simulation experiment result

Embodiment 6

The control condition of experiment water quality and circulating water system is with embodiment 5, five circulating water systems adopt series operation, the cycles of concentration of first step circulating water system is 2.0 ± 0.2, the cycles of concentration of second stage circulating water system is 3.0 ± 0.2, the cycles of concentration of third stage circulating water system is 4.0 ± 0.2, the cycles of concentration of fourth stage circulating water system is 5.0 ± 0.2, and the cycles of concentration of last step circulating water system is controlled to be 6.0 ± 0.2,15 days dynamic simulation experiment result such as table 8.

Table 8 dynamic simulation experiment result

Experimental result in the table 8 shows that the erosion rate of low cycles of concentration operational system test tube obviously reduces than the high concentration multiple operational system, and the treatment effect of water conditioner is better than the high concentration multiple operational system.

Embodiment 7

Experimental water is the standard discharge sewage of certain petroleum chemical enterprise, and water quality is as shown in table 9.

Carry out dynamic simulation experiment according to 407 methods in China PetroChemical Corporation's " water coolant analysis and experimental technique ", the quantity of circulating water of system is 150L/h, and the temperature difference of turnover saliva is 10 ℃.Experimental session, on-the-spot sewage is regulated the make up water of basicity as dynamic simulation experiment with sulfuric acid.The not pre-film of test tube, in vitro water flow velocity is controlled at 0.8m/s, and inflow temperature is controlled at 32 ℃, and leaving water temperature(LWT) is controlled at 40 ℃～42 ℃, and cycles of concentration is controlled at 6.0 ± 0.2, adds compound C, working concentration 100mg/L in the system.

Table 9 Analysis Results of Water Quality

With three circulating water system series operations, the cycles of concentration of first step circulating water system is 2.7 ± 0.2, the cycles of concentration of second stage circulating water system is 4.3 ± 0.2, and the cycles of concentration of third stage circulating water system is 6.0 ± 0.2,15 days dynamic simulation experiment result such as table 10 as requested.Experimental result shows in the table 10, and low cycles of concentration operational system water treatment effect is better than the high concentration multiple operational system.

Table 10 dynamic simulation experiment result

Embodiment 8

Experimental water is the standard discharge sewage of certain petroleum chemical enterprise, and water quality is as shown in table 9.

Carry out dynamic simulation experiment according to 407 methods in China PetroChemical Corporation's " water coolant analysis and experimental technique ", the quantity of circulating water of system is 150L/h, and the temperature difference of turnover saliva is 10 ℃.Experimental session, on-the-spot sewage is regulated the make up water of basicity as dynamic simulation experiment with sulfuric acid.The not pre-film of test tube, in vitro water flow velocity is controlled at 0.8m/s, and inflow temperature is controlled at 32 ℃, leaving water temperature(LWT) is controlled at 40 ℃～42 ℃, the concentration multiple of circulating water system of two independent operatings is respectively 5.0 ± 0.2 and 6.0 ± 0.2, adds compound C, working concentration 100mg/L in the system.

With above-mentioned two circulating water system series operations, the cycles of concentration of second stage circulating water system is 6.0 ± 0.2, and the cycles of concentration of first step circulating water system is 3.5 ± 0.2,15 days dynamic simulation experiment result such as a table 11.Experimental result shows in the table 11, and low cycles of concentration operational system water treatment effect is better than the high concentration multiple operational system.Total dosing and rate of water make-up are lower than the dosing and the rate of water make-up of two system's independent operatings.

Table 11 dynamic simulation experiment result

Claims (2)

1. recirculated cooling water system cascade using method, comprise: plural circulating water system tandem is used, the cycles of concentration of each circulating water system in the daisy chain moves according to order from low to high, the draining of previous circulating water system is directly as the make up water of next circulating water system, and the draining of last circulating water system is directly outer puts.

2. in accordance with the method for claim 1, it is characterized in that the cycles of concentration n of K circulating water system in the daisy chain _KCalculation formula is as follows:

$n_N>n_K\&GreaterEqual;\frac{(n_N-1)(E_1+E_2+E_3+\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;+E_K)}{E_1+E_2+E_3+\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;E_N}+1$

Wherein: n _NHigh concentration multiple when being a plurality of circulating water system isolated operation; E represents evaporated water, the m of unit ³/ h, N＞K 〉=1, evaporated water calculates by following formula:

$E=\frac{R\&times;\mathrm{\&Delta;t}}{580}$

In the formula, R represents quantity of circulating water, the m of unit ³/ h; Δ t expresses the import temperature difference, the C of unit.

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