CN102620143A - Optimization method for industrial circulating water system - Google Patents

Abstract

The invention discloses an optimization method for an industrial circulating water system. The optimization method comprises the following steps: 1, carrying out field measurement on the inlet and outlet temperature and the mass flow-rate of a cooling medium and a cooled medium in a heat exchanger in the circulating water system, and the input energy of water supply equipment; 2, according to the measurement data, determining the optimal mass flow-rate of the cooling medium in each heat exchanger, and according to the height difference and the temperature of the least favorable point of the system, determining the optimal pressure of the system; and 3, according to the obtained optimal mass flow-rate of the cooling medium and the obtained optimal pressure of the system, estimating and calculating the savable energy of a pump house by using an energy consumption balance method to determine whether the equipment is replaced or not, and if the savable energy is more than 5% of the input energy, considering the reconfiguration of the equipment. According to the optimization method, the optimal water supply amount and the necessary minimum pressure can be accurately calculated and the system is controlled to reach the requirements, the energy can be saved for the circulating water supply equipment, the running life of the system can be prolonged, and the production process is more reasonable.

Description

A kind of optimization method of industrial cycle water system

Technical field

The invention belongs to the industrial cycle water system, be specifically related to a kind of optimization method of industrial cycle water system.

Background technique

The circulation of present most of industrial and mining enterprise only rests on the level that guarantees to produce, and for various reasons, most of circulations energy in running is not fully used; Efficiency is lower; Energy consumption is higher, and its capacity usage ratio has only reached 25%～40%.Inlet temperature t ' like the medium that is cooled of the key equipment heat exchanger in the circulation ₁, outlet temperature t " ₁All less than design load, this possibly cause following problem under many circumstances:

1) medium that is cooled is cold excessively, influences the productivity effect of subsequent technique;

2) heat exchanger surface of heat exchanger is cold excessively, possibly cause fouling, slagging scorification, sticking ash easily, influences the life-span of heat exchanger;

3) circulating water of excessive supply is a kind of waste of energy;

4) the excessive system pressure that often causes of flow raises, and causes the run, drip, leak of system easily, influences the working life of whole system, increases the frequency of maintenance.

For the water system reducing energy consumption, existing technology provides some solutions, as the Chinese patent document just disclose " a kind of method for correcting error of online fluid system " (application number: 200710066873.2, publication number: CN101008475A).Although this method can be improved the energy-saving and cost-reducing problem of system to a certain extent; But it mainly solves is the do not match problem of (being commonly called as low load with strong power) of water pump assembly and system; Do not have system, solve in the circulation terminal mismatch problem all sidedly; Therefore whole system is optimized, makes its energy-saving and cost-reducing optimum level that reaches.

Summary of the invention

The object of the invention just provide a kind of can Accurate Analysis industrial cycle water system energy consumption level and through changing and transform the optimization method that water supply equipment significantly improves the industrial cycle water system of energy consumption level again.

Realize that the technological scheme that the object of the invention adopts is: the optimization method of industrial cycle water system may further comprise the steps:

One, the inlet temperature t ' of cooling medium in the heat exchanger in the in-site measurement circulation ₂, outlet temperature t " ₂Inlet temperature t ' with the medium that is cooled ₁, outlet temperature t " ₁, cooling medium flow mass M ₂Flow mass M with the medium that is cooled ₁Measure the intake P of water supply equipment in the circulation simultaneously _i

Two, according to the t ' that measures ₂, t " ₂, t ' ₁, t " ₁, M ₁, the best in quality flow M of the cooling medium of confirming each heat exchanger with the heat load equation of equilibrium and the iterative calculation method of heat exchanger _{2 (the bests)}, then the optimum flow value M of all heat exchangers _{2 (the bests)}Add up, obtain ∑ M _{2 (the bests)}, and confirm the optimum pressure H of system according to the discrepancy in elevation and the temperature of said system least favorable point _{(the best)}

Three, according to the best in quality flow ∑ M of the resulting cooling medium of step 2 _{2 (the bests)}, the optimum pressure H of system _{(the best)}But, with the conserve energy P of energy consumption balancing method reckoning pump house _j, analyze the energy consumption level of circulation; But according to conserve energy P _jDetermine whether more exchange device, if but conserve energy P _jBe less than or equal to intake P _i5%, do not need more exchange device, otherwise the new configuration device of quadruple set by step;

Four, according to the determined cooling medium best in quality of step 2 flow ∑ M _{2 (the bests)}With the optimum pressure H of system _{(the best)}, again optimal design, the adjustment circulation key parameter and equipment disposition.

Further technological scheme is:

In the said step 2, the best in quality flow M of cooling medium _{2 (the bests)}Confirm by following method:

According to formula (2)-(4) and formula group (5), establish M ₂Be variable, progressively approach, adopt iterative computing method, make t " ₁=t " _{1 (design)}Find the solution M _{2 (the bests)}

Q′＝M ₁c ₁(t″ ₁-t′ ₁)＝M ₂c ₂(t′ ₂-t″ ₂) (2)

Q′＝KFψΔt _m，c (3)

${\mathrm{\Δt}}_m,c=\frac{({t_1}^{\′\′}-{t_2}^{\′})-({t_1}^{\′}-{t_2}^{\′\′})}{\ln \frac{({t_1}^{\′\′}-{t_2}^{\′})}{({t_1}^{\′}-{t_2}^{\′\′})}}---\left(4\right)$

$\left\{\begin{array}{c}{M}_2{c}_2(t_2^{\′}-t_2^{\′\′})=M_1{c}_1(t_1^{\′\′}-t_1^{\′})=\mathrm{KF\ψ}{\mathrm{\Δt}}_m,c\\ {\mathrm{\Δt}}_m,c=\frac{({t_1}^{\′\′}-{t_2}^{\′})-({t_1}^{\′}-{t_2}^{\′\′})}{\ln \frac{({t_1}^{\′\′}-{t_2}^{\′})}{({t_1}^{\′}-{t_2}^{\′\′})}}\end{array}\right.---\left(5\right)$

In the formula:

c ₁For be cooled medium its inlet/outlet temperature temperature t ' ₁～t " ₁Level pressure quality specific heat in the scope;

c ₂For cooling medium its inlet/outlet temperature temperature t ' ₂～t " ₂Level pressure quality specific heat in the scope;

K is the mean heat transfer coefficient on the heat exchanger whole heat transfer face;

F is the heat exchanger heat transfer area;

ψ is the correction factor of various heat exchange device;

Δ t _m, c is a logarithmic mean temperature difference;

T " _{1 (design)}Design outlet temperature for the medium that is cooled;

In the said step 2, the said optimum pressure H of system _{(the best)}Confirm by following method:

The optimum pressure H of system _{(the best)}Under the situation by the discrepancy in elevation of least favorable point and temperature, the maintenance malleation is a principle, and by formula (6) are confirmed;

H _{(the best)}=H _{(safe clearance)}+ H _{(saturation vapour pressure)}+ H _{(pipe decreases)}(6)

In the formula:

H _{(safe clearance)}Be the safe clearance pressure of system, confirm with reference to industry standard or design handbook according to different industries and technology;

H _{(saturation vapour pressure)}Be the saturation vapour pressure of system, can in handbook, search the saturation vapour pressure under the different temperatures;

H _{(pipe decreases)}Pipe damage pressure for system is the frictional head loss Δ H on the whole pipeline _(mo)With the Δ H of local head loss _(j)Sum, Δ H _(no)With Δ H _(j)Calculate by formula (7) and (8) respectively:

${\mathrm{\ΔH}}_{\left(\mathrm{mo}\right)}=\mathrm{\λ}\frac{1}{d}\frac{v^2}{2g}---\left(7\right)$

${\mathrm{\ΔH}}_{\left(j\right)}=\mathrm{\ζ}\frac{v^2}{2g}---\left(8\right)$

In the formula: λ is the on-way resistance coefficient, and l is a flow development length, and d is a caliber, and υ is the mean velocity on the effective section, g gravity accleration, ζ coefficient of partial resistance;

In the said step 3, but the conserve energy P of pump house _jConfirm by following method:

S1 confirms the essential hydraulic energy P that water pump externally provides with formula (9) _e:

$P_e=\frac{\mathrm{\ρgQH}}{1000}=\frac{\mathrm{\γQH}}{1000}---\left(9\right)$

In the formula:

ρ is a Media density;

γ is a medium severe;

Q is the ∑ M that previous calculations draws _{2 (the bests)}, M _{2 (the bests)}Be mass flow rate in the formula in front, bring this formula into and should convert volume flowrate into;

H is system's optimum pressure that previous calculations draws _{H (the best)}

G is a gravity accleration;

S2 with formula (10), (11) thus but calculate the conserve energy P that the pump house loss calculates system _j

P _Loss=P _i-P _e(10)

P _j=P _Loss-P _b(11)

Intake P wherein _iDirectly the electric energy meter with pump house measures, or calculates through the electric energy formula of standard, establishes P _bBe necessary loss, add up the necessary loss P of whole pump house according to practical experience _bAt P _e17%～25% between.

In the said step 4, said equipment disposition is confirmed by following method:

The flow of water pump is directly pressed ∑ M _{2 (the bests)}The optimum pressure H of the system that configuration, the lift of water pump draw by previous calculations _{(the best)}Configuration; Motor running load rate is 75% when following, the allocating power canceller, and load factor should be changed motor 50% when following.

Described heat exchanger comprises preheater (or heater), cooler, condenser, vaporizer etc.

Be cooled medium and the cooling medium chatted should be understood like this:

Medium is cooled: in actual production, in order to guarantee normal process requirements and production safety, needing by the fluid of control temperature and flow, is the main body in the production technology;

Cooling medium: reaching required temperature and flow in order to guarantee and to control the medium that is cooled, be used for absorbing and increasing the fluid of the medium temperature that is cooled, is to be auxiliary in the production technology;

So the medium that is cooled is the convenience in order to call just, and may not be exactly the hot fluid on the engineering, cooling medium also is the convenience in order to call, and may not be exactly the cold fluid on the engineering.

The beneficial effect of the inventive method:

The present invention regards whole circulation water as a total system and studies, calculates; Utilization to energy consumption is more reasonable; The operating energy consumption of heat-transfer effect, pumping station that the inventive method can be handled heat exchanger (in enterprise, also being called end) is utilized the associated design problem of effect and heat exchanger and pumping station; Can be widely used in the energy consumption monitoring of industrial circulating water; More can be used in the budget and energy saving optimizing design to the energy saving of system potentiality, be that a kind of theoretical foundation is abundant, the reckoning process is clear, thinking is tight, the energy-conservation technological transformation method of strong operability.

The inventive method can accurately calculate and control system reaches optimum water output and necessary pressure minimum, except can be on the circulating water water supply equipment energy-conservation, the service life of system is increased, and production technology is more reasonable.

Description of drawings

Fig. 1 is the industrial circulating water system schematic.

Fig. 2 is a heat exchanger parameter measurement key plan.

Embodiment

The industrial cycle water system is as shown in Figure 1, comprises cooling unit, water supply installation and water device, and the water device mainly is a heat exchanger.The optimization method method of industrial cycle water system of the present invention may further comprise the steps:

One, as shown in Figure 2, the inlet temperature t ' of cooling medium in the heat exchanger in the in-site measurement circulation ₂, outlet temperature t " ₂Inlet temperature t ' with the medium that is cooled ₁, outlet temperature t " ₁, cooling medium flow mass M ₂, the medium that is cooled flow mass M ₁, the intake P of water supply equipment in the circulation (pump house) _i

Measure temperature and use thermometer; Measure mass flow rate with fixed or portable flowmeter, also can adopt corresponding sensor and teletransmission equipment to carry out remote detection and can also adopt corresponding sensor to carry out the strange land detection through signal collecting device and wireless (wired) signal transmission apparatus.The intake P of pump house _iCan measure with three-phase electric energy meter, also can calculate through the electric energy formula of standard, computational methods are following:

1) detects electric current I, voltage U, the powerfactorcos that pump house is imported;

2) substitution formula (1) calculates

Two, according to the t ' of last planar survey ₂, t " ₂, t ' ₁, t " ₁, M ₂, M ₁, the best in quality flow M that confirms cooling medium with the heat load equation of equilibrium (2) and the iterative calculation method of heat exchanger _{2 (the bests)}, confirm the optimum pressure H of system according to the discrepancy in elevation and the temperature of system's least favorable point _{(the best)}, specific practice is following:

S1 confirms cooling medium best in quality flow M _{2 (the bests)}: the heat load equation of equilibrium of heat exchanger is:

Q′＝M ₁c ₁(t″ ₁-t′ ₁)＝M ₂c ₂(t′ ₂-t″ ₂) (2)

In the formula:

M ₁Mass flow rate for the medium that is cooled;

T ' ₁And t " ₁Be respectively be cooled medium inlet temperature and outlet temperature;

T ' ₂And t " ₂Be respectively cooling medium inlet temperature and outlet temperature;

c ₁For be cooled medium its inlet/outlet temperature temperature t ' ₁～t " ₁Level pressure quality specific heat (can check in) in the scope by the related tool book;

c ₂For cooling medium its inlet/outlet temperature temperature t ' ₂～t " ₂Level pressure quality specific heat (can check in) in the scope by the related tool book;

Q ' is the actual heating load of heat exchanger;

The heat transfer formula of heat exchanger is:

Q′＝KFψΔt _m，c (3)

In the formula:

Q ' is the actual heating load of heat exchanger;

K is the mean heat transfer coefficient on the heat exchanger whole heat transfer face;

F is the heat exchanger heat transfer area;

ψ is the correction factor (produced in test provide by heat exchanger manufacturer) of various heat exchange device;

Δ t _m, c for by reflux type by formula (4) calculate logarithmic mean temperature difference;

${\mathrm{\Δt}}_m,c=\frac{({t_1}^{\′\′}-{t_2}^{\′})-({t_1}^{\′}-{t_2}^{\′\′})}{\ln \frac{({t_1}^{\′\′}-{t_2}^{\′})}{({t_1}^{\′}-{t_2}^{\′\′})}}---\left(4\right)$

Following formula group (5) is carried out simultaneous solution:

$\left\{\begin{array}{c}{M}_2{c}_2(t_2^{\′}-t_2^{\′\′})=M_1{c}_1(t_1^{\′\′}-t_1^{\′})=\mathrm{KF\ψ}{\mathrm{\Δt}}_m,c\\ {\mathrm{\Δt}}_m,c=\frac{({t_1}^{\′\′}-{t_2}^{\′})-({t_1}^{\′}-{t_2}^{\′\′})}{\ln \frac{({t_1}^{\′\′}-{t_2}^{\′})}{({t_1}^{\′}-{t_2}^{\′\′})}}\end{array}\right.---\left(5\right)$

In the formula:

K, F, ψ all confirm (being generally the data of dispatching from the factory) by the experiment of dispatching from the factory of producer, and be known;

c ₁, c ₂Check in by reference book respectively, known;

M ₁, t ' ₁For the in-site measurement data, known; T ' ₂For the temperature of bringing after cooling tower (pond) radiating treatment, also be constant, bring the in-site measurement data into, known;

In formula group (5), we are made as variable M ₂, progressively approach, adopt iterative computing method, find the solution M _{2 (the bests)}: promptly M ₂Reduce on the basis of former flow that (general per step reduces former flow M ₂0.1%) calculate t " ₁, t ₂" numerical value, constantly like this repeat above process, " until the in-site measurement outlet temperature t of the medium that is cooled ₁Equal its design outlet temperature t " _{1 (design)}, just meet design requirement M at this time ₂Be cooling medium best in quality flow M _{2 (the bests)}T wherein ₂" just in computational process, keeping the balance of formula, is not the result that we need, and for the situation of many heat exchangers, only needs the optimum flow M with each heat exchanger _{2 (the bests)}Numerical value add up ∑ M _{2 (the bests)}

S2 confirms the optimum pressure H of system according to the discrepancy in elevation and the temperature of system's least favorable point by conventional method _{(the best)}:

The optimum pressure H of system _{(the best)}Under the situation by the discrepancy in elevation (potential energy) of least favorable point and temperature, the maintenance malleation is a principle, and the pressure of least favorable point must be put the setting pressure instrument at least favorable and monitor, and guarantees security of system;

The optimum pressure H of system _{(the best)}=H _{(safe clearance)}+ H _{(saturation vapour pressure)}+ H _{(pipe decreases)}(6)

In the formula: H _{(safety is surplus)}Be the safe clearance pressure of system, confirm with reference to industry standard or design handbook according to different industries and technology;

H _{(saturation vapour pressure)}Be the saturation vapour pressure of system, can in handbook, search about the saturation vapour pressure under the different temperatures of the cold true medium of native system;

H _{(pipe decreases)}Pipe damage pressure for system is the frictional head loss Δ H on the whole pipeline _(mo)With the Δ H of local head loss _(j)Sum, Δ H _(mo)With Δ H _(j)Calculate by formula (7) and (8) respectively:

${\mathrm{\ΔH}}_{\left(\mathrm{mo}\right)}=\mathrm{\λ}\frac{1}{d}\frac{v^2}{2g}---\left(7\right)$

${\mathrm{\ΔH}}_{\left(j\right)}=\mathrm{\ζ}\frac{v^2}{2g}---\left(8\right)$

In the formula: λ is on-way resistance coefficient (looking into handbook), and l is a flow development length, and d is a caliber, and υ is the mean velocity on the effective section, and g is a gravity accleration, and ζ is coefficient of partial resistance (looking into handbook);

Three, according to the best in quality flow ∑ M of the resulting cooling medium of step 2 _{2 (the bests)}With system's optimum pressure _{H ( Good)}But, with the conserve energy P of energy consumption balancing method reckoning pump house _i:

S1 confirms the necessary hydraulic energy P that water pump externally provides with formula (9) _e:

$P_e=\frac{\mathrm{\ρgQH}}{1000}=\frac{\mathrm{\γQH}}{1000}---\left(9\right)$

In the formula:

ρ is a Media density;

γ is that medium is heavy;

Q is the ∑ M that previous calculations draws _{2 (the bests)}, M _{2 (the bests)}Be mass flow rate in the formula in front, bring this formula into and should convert volume flowrate into;

H is the optimum pressure H of system that previous calculations draws _{(the best)}

G is a gravity accleration;

P _eBe necessary hydraulic energy;

S2 through formula (10), (11) thus but calculate the conserve energy P that the pump house loss calculates system _j

The energy consumption equation of equilibrium of pump house is:

P _Loss=P _i-P _e(10)

Intake P wherein _iDirectly the electric energy meter with pump house measures, or calculates through the electric energy formula of standard, establishes P _bBe necessary loss, add up the necessary loss P of whole pump house according to practical experience _bAt P _e17%～25% between, but conserve energy P so _jAvailable formula (11) calculates

P _j=P _Loss-P _b(11)

But according to conserve energy P _jDetermine whether more exchange device, if but conserve energy P _jBe less than or equal to intake P _i5%, do not need more exchange device, otherwise the new configuration device of quadruple set by step;

Four, according to the determined cooling medium best in quality of step 2 flow ∑ M _{2 (the bests)}, again optimal design, the adjustment circulation key parameter and equipment disposition:

The flow of water pump is directly pressed cooling medium best in quality flow ∑ M _{2 (the bests)}Configuration, the lift of water pump add the pressure loss sum configuration of transfer conduit by system's optimum pressure; Wherein, the pressure loss of transfer conduit draws by plumbing criterion calculation method; Motor running load rate is 75% when following, the allocating power canceller, and load factor is changed motor, in order to avoid because the low influence that electrical network is caused of power factor 50% when following.

Application example:

Organization name: certain dress ornament city (central air-conditioning system)

One, the inlet temperature t ' of cooling medium in the heat exchanger in the in-site measurement circulation ₂, outlet temperature t " ₂Inlet temperature t ' with the medium that is cooled ₁, outlet temperature t " ₁, the medium that is cooled flow mass M ₁, the intake P of system's (pump house) _i, and with design load t " _{2 (designs)}Compare;

Air-conditioner host nameplate parameter:

Title	The centrifugal unit of water-cooled (CVHE/G)
		Model	CVHG107RA2BOCCY293CCAECBIC
Unit design cold	389(1100)KW(TONS)

Be under 36.7 ℃ the situation, to measure air-conditioner host runnability (the normal and stable operation is after 1 hour) in current environmental temperature:

The parameter title	Code name	Measured value	Design load	Unit
					The rapid steamer entering water temp	t′ 1	12.2	12.5	℃
The rapid steamer water-exit temperature	t″ 1	7	8.8	℃
					The rapid steamer chilled-water flow	M 1	950	663	m 3/h
The condenser entering water temp	t′ 2	30.7	31	℃
					The condenser water-exit temperature	t″ 2	35.2	37	℃
The condenser cooling water flow	M 2	1050	783	m 3/h
					The main frame electric current		781×3		A

Measure former coolant pump runnability:

Draw the intake P of pump house by last table _iBe 59.7w;

Two, according to the t ' that measures ₂, t " ₂T ' ₁, t " ₁, M ₂, M ₁, confirm the best in quality flow M of cooling medium with formula (2)-(5) and iterative calculation method _{2 (the bests)}, confirm system's optimum pressure according to the discrepancy in elevation and the temperature of system's least favorable point _{H (the best)}

During iterative computation: M ₂Per step reduces 0.1% of former flow on the basis of former flow, until t " 1=t " _{1 (design)}, just meet design requirement, as t " ₂In the time of=8.8 ℃, try to achieve M _{2 (the bests)}=790m ³/ h

Optimum pressure according to formula (6)-(8) computing system _{H (the best)}

Through searching handbook, H _{(safe clearance)}, H _{(saturation vapour pressure)}Be respectively 0.8m, 0.58m, through calculating H _{(pipe decreases)}Be 13.4m, draw H _{(the best)}Be about 15m;

Three, according to resulting optimum flow M ₂, the optimum pressure H of system _{(the best)}Intake P with the pump house of measuring _i, with the formula in the energy consumption balancing method (9)-(11) but calculate pump house conserve energy P _i

Calculating P _jThe time establish P _Loss=19%

But through calculating pump house conserve energy P _j=31.7Kw is greater than the intake P of pump house _i5%, conclusion is that input and output are bigger, should carry out energy-conservation technological transformation;

Four, according to determined optimum flow M ₂, the key parameter of optimal design, adjustment circulation is to the M of above-mentioned calculating again _{2 (the bests)}, H _{(the best)}And carry out corresponding equipment disposition, design supporting water pump again;

Water pump parameter and runnability after supporting are:

And adjustment exit of pump valve opening is 100%, and last tower valve opening is 100%, and the coolant pump amount of electricity saving is 30.46% after the system reform.

Claims (5)

1. the optimization method of an industrial cycle water system is characterized in that may further comprise the steps:

One, the inlet temperature t ' of cooling medium in the heat exchanger in the in-site measurement circulation ₂, outlet temperature t " ₂Inlet temperature t ' with the medium that is cooled ₁, outlet temperature t " ₁, cooling medium flow mass M ₂Flow mass M with the medium that is cooled ₁Measure the intake P of water supply equipment in the circulation simultaneously _i

Two, according to the t ' that measures ₂, t " ₂, t ' ₁, t " ₁, M ₁, the best in quality flow M of the cooling medium of confirming each heat exchanger with the heat load equation of equilibrium and the iterative calculation method of heat exchanger _{2 (the bests)}, then the optimum flow value M of all heat exchangers _{2 (the bests)}Add up, obtain ∑ M _{2 (the bests)}, and confirm the optimum pressure H of system according to the discrepancy in elevation and the temperature of said system least favorable point _{(the best)}

Three, according to the best in quality flow ∑ M of the resulting cooling medium of step 2 _{2 (the bests)}, the optimum pressure H of system _{(the best)}But, with the conserve energy P of energy consumption balancing method reckoning pump house _j, analyze the energy consumption level of circulation; But according to conserve energy P _iDetermine whether more exchange device, if but conserve energy P _jBe less than or equal to intake P _i5%, do not need more exchange device, otherwise the new configuration device of quadruple set by step;

Four, according to the determined cooling medium best in quality of step 2 flow ∑ M _{2 (the bests)}With the optimum pressure H of system _{(the best)}, again optimal design, the adjustment circulation key parameter and equipment disposition.

2. the optimization method of industrial cycle water system according to claim 1 is characterized in that:

In the said step 2, the best in quality flow M of cooling medium _{2 (the bests)}Confirm by following method:, establish M according to formula (2)-(4) and formula group (5) ₂Be variable, progressively approach, adopt iterative computing method, make t ' ₁=t " _{1 (design)}Find the solution M _{2 (the bests)}

Q′＝M ₁c ₁(t″ ₁-t′ ₁)＝M ₂c ₂(t′ ₂-t″ ₂) (2)

Q′＝KFψΔt _m，c (3)

${\mathrm{\Δt}}_m,c=\frac{({t_1}^{\′\′}-{t_2}^{\′})-({t_1}^{\′}-{t_2}^{\′\′})}{\ln \frac{({t_1}^{\′\′}-{t_2}^{\′})}{({t_1}^{\′}-{t_2}^{\′\′})}}---\left(4\right)$

$\left\{\begin{array}{c}{M}_2{c}_2(t_2^{\′}-t_2^{\′\′})=M_1{c}_1(t_1^{\′\′}-t_1^{\′})=\mathrm{KF\ψ}{\mathrm{\Δt}}_m,c\\ {\mathrm{\Δt}}_m,c=\frac{({t_1}^{\′\′}-{t_2}^{\′})-({t_1}^{\′}-{t_2}^{\′\′})}{\ln \frac{({t_1}^{\′\′}-{t_2}^{\′})}{({t_1}^{\′}-{t_2}^{\′\′})}}\end{array}\right.---\left(5\right)$

In the formula:

c ₁For be cooled medium its inlet/outlet temperature temperature t ' ₁～t " ₁Level pressure quality specific heat in the scope;

c ₂For cooling medium its inlet/outlet temperature temperature t ' ₂～t " ₂Level pressure quality specific heat in the scope;

K is the mean heat transfer coefficient on the heat exchanger whole heat transfer face;

F is the heat exchanger heat transfer area;

ψ is the correction factor of various heat exchange device;

Δ t _m, c is a logarithmic mean temperature difference;

T " _{1 (design)}Design outlet temperature for the medium that is cooled.

3. the optimization method of industrial cycle water system according to claim 1 is characterized in that:

In the said step 2, the said optimum pressure H of system _{(the best)}Confirm by following method:

The optimum pressure H of system _{(the best)}Under the situation by the discrepancy in elevation of least favorable point and temperature, the maintenance malleation is a principle, and by formula (6) are confirmed;

H _{(the best)}=H _{(safe clearance)}+ H _{(saturation vapour pressure)}+ H _{(pipe decreases)}(6)

In the formula:

H _{(safe clearance)}Be the safe clearance pressure of system, confirm with reference to industry standard or design handbook according to different industries and technology;

H _{(saturation vapour pressure)}Be the saturation vapour pressure of system, can in handbook, search the saturation vapour pressure under the different temperatures;

H _{(pipe decreases)}Pipe damage pressure for system is the frictional head loss Δ H on the whole pipeline _(mo)With the Δ H of local head loss _(j)Sum, Δ H _(mo)With Δ H _(j)Calculate by formula (7) and (8) respectively:

${\mathrm{\ΔH}}_{\left(\mathrm{mo}\right)}=\mathrm{\λ}\frac{1}{d}\frac{v^2}{2g}---\left(7\right)$

${\mathrm{\ΔH}}_{\left(j\right)}=\mathrm{\ζ}\frac{v^2}{2g}---\left(8\right)$

In the formula: λ is the on-way resistance coefficient, and l is a flow development length, and d is a caliber, and υ is the mean velocity on the effective section, g gravity accleration, ζ coefficient of partial resistance.

4. the optimization method of industrial cycle water system according to claim 1 is characterized in that:

In the said step 3, but the conserve energy P of pump house _jConfirm by following method:

S1 confirms the essential hydraulic energy P that water pump externally provides with formula (9) _e:

$P_e=\frac{\mathrm{\ρgQH}}{1000}=\frac{\mathrm{\γQH}}{1000}---\left(9\right)$

In the formula:

ρ is a Media density;

γ is a medium severe;

Q is the ∑ M that previous calculations draws _{2 (the bests)}, M _{2 (the bests)}Be mass flow rate in the formula in front, bring this formula into and should convert volume flowrate into;

H is the optimum pressure H of system that previous calculations draws _{(the best)}

G is a gravity accleration;

S2 with formula (10), (11) thus but calculate the conserve energy P that the pump house loss calculates system _j

P _Loss=P _i-P _e(10)

P _j=P _Loss-P _b(11)

Intake P wherein _iDirectly the electric energy meter with pump house measures, or calculates through the electric energy formula of standard, establishes P _bBe necessary loss, add up the necessary loss P of whole pump house according to practical experience _bAt P _e17%～25% between.

5. the optimization method of industrial cycle water system according to claim 1 is characterized in that:

In the said step 4, said equipment disposition is confirmed by following method:

The flow of water pump is directly pressed ∑ M _{2 (the bests)}The optimum pressure H of the system that configuration, the lift of water pump draw by previous calculations _{(the best)}Configuration; Motor running load rate is 75% when following, the allocating power canceller, and load factor should be changed motor 50% when following.

Images