Summary of the invention
The present invention is directed to the deficiencies in the prior art, it is proposed that a kind of whole process rolling reverse osmosis seawater desalination system operation is excellent
Change method.The method, according to the reverse osmosis mechanism of seawater desalination system and the structure of whole flow process, uses the side of exact mechanism
Formula establishes full-range reverse osmosis controlling the water circulation and the accurate model of water-retention process, and model uses differential algebraic equations to describe, and
Product water process and water supply process are linked up, utilizes the cushioning effect of cistern and the stepped change of electricity price to reduce total gymnastics
Make expense.The optimal problem that the differential algebra form brought to solve Accurate Model describes, uses simultaneous solution technology to excellent
Change proposition to solve.The present invention is conducive to the enforcement of system on-line optimization technology, has extraordinary Energy-saving Perspective.The present invention
Consider the multiple variable element influence factor of seawater desalination system, set up the whole process systematic procedure model of variable element,
By the operation optimization of simultaneous Optimization Solution technical research seawater desalination system, try hard to reduce seawater desalination system further and run
Cost.
The present invention comprises the following steps:
Step 1: set up rolling reverse osmosis seawater desalting controlling the water circulation process model.
The basic procedure of rolling reverse osmosis seawater desalination system is as shown in Figure 1.According to reverse osmosis process mechanism and quality,
Law of conservation of energy, rolling embrane method reverse osmosis process model can use below equation to be described.
Qp=Qf-Qr (1)
QfCf=QrCr+QpCsp (2)
Jv=Aw(Pf-Pd-Pp-Δπ) (4)
Js=Bs(Cm-Cp) (5)
Pb=Pf-Pd (6)
Δ P=(Pb-Pp) (7)
Δ π=RT (Cm-Cp) (10)
Re=ρ Vde/μ (13)
Sc=μ/(ρ DAB) (14)
Js=Jv*Cp (15)
λ=6.23KλRe-0.3 (16)
Rec=Qp/Qf (23)
SEC=(PfQf/ηHP-PrQrηPX)/Qp (24)
Sp=Cp/Cf× 100% (25)
Ry=(1-Cp/Cf) × 100% (26)
In above equation: Qf、Qp、QrRepresent sea water feed rate, infiltration discharge and strong brine flow, C respectivelyf、Cp、Cr
Represent charging salinity, the salinity of infiltration water and strong brine salinity, n respectivelylRepresent the blade quantity of RO film, nPVRepresent pressure
The number of force container, W represents RO film width, and L represents the length of RO passage, JvRepresent solvent flux, JsRepresent Solute flux, Aw
Represent film coefficient of permeability, Aw0Represent the intrinsic coefficient of permeability of film, BsFilm saturating salt coefficient, Bs0Film intrinsic salt coefficient, PbRepresent charging
The pressure of passage maritime interior waters, PdRepresent the pressure loss along RO passage, PpRepresent that the pressure of infiltration water side (is generally defaulted as ring
Border pressure), Δ P represents feed water and the pressure differential of infiltration water in passage, and T represents sea water feeding temperature, α1, α2, β1Represent respectively
Continuative transport parameter, Δ π represents that osmotic pressure, R represent gas law constant, CmRepresent the salinity of the feed side on film surface, φ
Represent concentration polarization parameter, CbRepresenting the salt concentration of sea-water along feeding-passage, Sh represents sherwood number, kcRepresent mass tranfer coefficient, table
Show DABRepresent dynamic viscosity, deRepresenting feed spacer passage hydraulic diameter, Re represents that Reynolds number, Sc represent that Schmidt number, ρ represent
The density of infiltration water, μ represents that apparent viscosity, λ represent coefficient of friction, KλRepresenting empirical parameter, V represents charging axially stream in passage
Speed, hspRepresent the height of feed spacer passage, RecRepresenting Water Sproading rate, SEC representation unit produces water consumption, ηHPRepresent high-pressure pump
Mechanical output, ηPXRepresenting the organic efficiency of energy recycle device, Ry represents that salt rejection rate, Sp are that salt leads to coefficient.
Model above has taken into full account temperature, pressure and the sea water salinity change impact on reverse osmosis process, model
There is the good suitability.In order to ensure the accuracy of model, equation gives physical parameter along with temperature, salinity change
And situation about changing.
Step 2. sets up cistern dynamic process model
The importation of cistern is to come from the infiltration water that reverse osmosis controlling the water circulation process (RO process) obtains, and output unit is divided into
The fresh water of supply user, because the last handling processes such as pH value regulation are the least on the impact of whole water-retention process, can ignore at this.
Therefore, the dynamic process model of cistern is represented by:
Here, t express time, StAnd HtRepresent area and the water level of cistern, Q respectivelypFor infiltration discharge, QoutFor with
Family water requirement, Ct,outFor the fresh water salinity of output to user, CspSalinity for the per-meate side that reverse osmosis controlling the water circulation process obtains
(CpFor CspValue at modular terminal), for guaranteeing that system operates safety, cistern water level must is fulfilled for Ht,lo<Ht<Ht,up。QpWith
CspValue obtained by reverse osmosis process model.
Step 3. sets up system operating cost model
According to rolling reverse osmosis seawater desalting process flow and real process feature, system operating cost
(operational cost, OC) specifically includes that 1) .RO process operation energy consumption cost (OCEN), predominantly high-pressure pump, booster pump
And the energy consumption of energy-recuperation system.2). seawater taking system and early stage preprocessing process energy consumption cost (OCIP).3). chemistry adds
Add the expense (OC of agentCH), predominantly acid adding, add the expense of the aspect such as antisludging agent and flocculant.4). reverse osmosis membrane renewal cost
(OCME).According to design and ruuning situation, the year turnover rate generally according to about 15-20% calculates.5). upkeep cost (OCMN)。
Comprise the upkeep cost of whole system such as film, high-pressure pump, motor etc..6). labour cost (OCLB)。
The operating cost of sea water water intaking and pretreatment system mainly includes chemical addition agent expense and seawater taking system
With early stage preprocessing process energy consumption cost.According to operating experience, the expense of chemical addition agent is represented by:
OCCH=FUCHQf=0.0225Qf (29)
Seawater taking system is expressed as with early stage preprocessing process energy consumption cost:
Here, PinRepresent the outlet pressure of water pump.QfRepresenting feed rate, PLF represents load factor, PelcRepresent electricity
Power price, ηIPRepresent the efficiency of sea water water pump.
For RO process unit, operating cost mainly include high-pressure pump and booster pump energy consumption cost, film renewal cost and
The energy consumption cost that energy recycle device is saved.High-pressure pump energy consumption cost is expressed as:
PfRepresent high pressure pump outlet pressure, P0Represent high pressure pump inlet pressure, ηHPRepresent the mechanical efficiency of high-pressure pump, ηVFD
Representing the efficiency of converter, its value changes along with frequency change.
The energy consumption cost that energy recycle device is saved is expressed as:
OCPX=Qr·(Pr-Pa)·ηPX·Pelc (32)
QrRepresent the flow of concentrated solution, PrRepresent the pressure head of concentrated solution, PaRepresent strong brine from energy recycle device out time
The pressure waited, ηPXRepresent the efficiency of pressure exchanger.The energy consumption cost of booster pump is then expressed as:
OCBP=Q2·(Pf-Ps)/ηBP·Pelc (33)
Here, Q2Represent the flow by high-pressure pump, PsRepresent the seawater pressure after energy regenerating, ηBPRepresent booster pump
Mechanical efficiency.
So energy consumption of reverse osmosis controlling the water circulation process is represented by:
OCEN=OCHP-OCPX+OCBP (34)
Reverse osmosis membrane renewal cost is represented by:
OCME=PriME×MOD×ζre/365 (35)
Here PriMERepresenting the price of single membrane module, MOD represents the number of membrane module, ξreRepresent the year of membrane module more
Change rate.
The upkeep cost of system is relevant with practical operation situation and system investments situation, can be expressed as under normal circumstances
Routine operation expense is multiplied by the proportionality coefficient of a 3%-5%, as follows:
OCMN=OCNom×CoeMN (36)
Here OCNomThe routine operation expense of expression system, CoeMNRepresent proportionality coefficient.Labour cost is then according to workman's
Wage and number determine, typically constitute from the 8%-15% of routine operation expense, are represented by:
OCLB=OCNom×CoeLB (37)
Here CoeLBRepresent the proportionality coefficient of system convention operating cost shared by labour cost.
Step 4. is according to model above and the target of reduction system operating cost, constructing system operation optimization proposition.
In order to reduce the running cost of system, it is required that the operating cost of system is minimum.Because either water supply load
Or electricity rates or ocean temperature, all have the approximation characteristic with a day as cycle, therefore to optimize conveniently, with one day
The minimum target of operating cost carry out the operation optimization of system.In view of facility constraints and electricity rates situation of change, with 1
Hour regulate performance variable (its feed rate Q for unitfWith feed pressure Pf).Therefore, the object function of optimization can represent
For:
In order to solve the operating cost of each several part in object function, meet water supply quality and want summation device security constraint, excellent
The constraint equation changing proposition is represented by following form:
Equality constraint equation:
Reverse osmosis process model (eqn. (1)-(26)) (38b)
Cistern dynamic process model (eqn. (27)-(28)) (38c)
Operating cost model (eqn. (29)-(37)) (38d)
Inequality constraints:
Water quality retrains: Ct,out≤Cwq,limit (38e)
Antiscale retrains: Cr≤Cr,limit (38f)
Concentration polarization restriction on the parameters: φ≤1.2 (38g)
Equipment pressure confines: Pf,lo≤Pf≤Pf,up (38h)
RO module flow rate retrains: Vf,lo≤Vf≤Vf,up (38i)
Cistern restriction of water level Ht,lo<Ht<Ht,up (38j)
Boundary condition:
Ht(0)-Ht(24)=0 (38k)
Initial and end condition:
Z=0, V=Vf=Qf/(nlWhsp);Pb=Pf;Cb=Cf;
Z=L, V=Vr=Qr/(nlWhsp);Z=L, Pb=Pr;Cb=Cr (38l)
Wherein Cwq,limitRepresent water supply salinity limit value, Cr,limitRepresent the strong brine salinity limit that reverse osmosis process produces
Value, Pf,lo、Vf,loAnd Ht,loRepresent the lower limit of relevant parameter, P respectivelyf,up、Vf,upAnd Ht,upRepresent the upper limit of relevant parameter respectively.
Ht(0) water level at the 0th hour, H are representedt(24) water level at the 24th hour is represented.
The operation optimization proposition formed is solved by step 5..
The optimal problem being made up of formula (38a)-(38l) had both comprised strong nonlinearity algebraic equation, comprised again the differential equation, for
Solve conveniently, use finite element collocation method to be formed by its most discrete non-linear algebraic equation that turns to, form formula (39) and represent
Nonlinear optimal problem.Then use large-scale nonlinear solver that it is optimized to solve, it is thus achieved that optimal objective function
Value and the optimal value of performance variable.With the performance variable optimal value that obtains as setting value, autocontrol method is used to strain mutually
Amount controls at setting value, then the operation optimization of feasible system.Here the finite element collocation method used is conventional method, greatly
Scale nonlinear optimization solver is the solver based on sequential quadratic programming algorithm or interior-point algohnhm.Mentioned here automatically
Control method both can be regulatory PID control method, it is also possible to be advanced control method.
The beneficial effects of the present invention is: the present invention considers charging ocean temperature, salinity etc. to reverse osmosis produced water
Impact, establishes strict each several part model accurately, the adaptability of model and accuracy high;The present invention is by controlling the water circulation process and water supply
Combine processes gets up to consider, equal diversity when utilizing water-holding capacity and the electricity rates of cistern, it is possible to obtain the most energy-conservation
Effect;The Optimization Solution strategy that the present invention uses is conducive to the on-line implement of operation optimization, can preferably analyze whole process
Internal state change and operating cost composition.
Detailed description of the invention
Below in conjunction with accompanying drawing, the invention will be further described.
The inventive method comprises the following steps:
Step 1: set up rolling reverse osmosis seawater desalting controlling the water circulation process model.
The basic procedure of rolling reverse osmosis seawater desalination system is as shown in Figure 1.According to reverse osmosis process mechanism and quality,
Law of conservation of energy, rolling embrane method reverse osmosis process model can use below equation to be described.
Qp=Qf-Qr (1)
QfCf=QrCr+QpCsp (2)
Jv=Aw(Pf-Pd-Pp-Δπ) (4)
Js=Bs(Cm-Cp) (5)
Pb=Pf-Pd (6)
Δ P=(Pb-Pp) (7)
Δ π=RT (Cm-Cp) (10)
Re=ρ Vde/μ (13)
Sc=μ/(ρ DAB) (14)
Js=Jv*Cp (15)
λ=6.23KλRe-0.3 (16)
Rec=Qp/Qf (23)
SEC=(PfQf/ηHP-PrQrηPX)/Qp (24)
Sp=Cp/Cf× 100% (25)
Ry=(1-Cp/Cf) × 100% (26)
In above equation: Qf、Qp、QrRepresent sea water feed rate, reverse osmosis water flow and strong brine flow, C respectivelyf、Cp、
CrRepresent charging salinity, the salinity of reverse osmosis water and strong brine salinity, n respectivelylRepresent the blade quantity of RO film, nPVTable
Showing the number of pressure vessel, W represents RO film width, and L represents the length of RO passage, JvRepresent solvent flux, JsRepresent that solute leads to
Amount, AwRepresent film coefficient of permeability, Aw0Represent the intrinsic coefficient of permeability of film, BsFilm saturating salt coefficient, Bs0Film intrinsic salt coefficient, PbRepresent
The pressure of feeding-passage maritime interior waters, PdRepresent the pressure loss along RO passage, PpRepresent that infiltration water lateral pressure (is generally defaulted as
Ambient pressure), Δ P represents feed water and the pressure differential of infiltration water in passage, and T represents sea water feeding temperature, α1, α2, β1Table respectively
Show that continuative transport parameter, Δ π represent that osmotic pressure, R represent gas law constant, CmRepresent the salinity of the feed side on film surface,
φ represents concentration polarization parameter, CbRepresenting along feeding-passage concentration of seawater, Sh represents sherwood number, kcRepresent mass tranfer coefficient, represent
DABRepresent dynamic viscosity, deRepresenting feed spacer passage hydraulic diameter, Re represents that Reynolds number, Sc represent that Schmidt number, ρ represent and ooze
Permeable density, μ represents that apparent viscosity, λ represent coefficient of friction, KλRepresenting empirical parameter, V represents charging axially stream in passage
Speed, hspRepresent the height of feed spacer passage, RecRepresenting Water Sproading rate, SEC representation unit produces water consumption, ηHPRepresent high-pressure pump
Mechanical output, ηPXRepresenting the organic efficiency of energy recycle device, Ry represents that salt rejection rate, Sp are that salt leads to coefficient.
Model above has taken into full account temperature, pressure and the sea water salinity change impact on reverse osmosis process, model
There is the good suitability.In order to ensure the accuracy of model, equation gives physical parameter along with temperature, salinity change
And situation about changing.
Step 2. sets up cistern dynamic process model
The importation of cistern is to come from the infiltration water that reverse osmosis controlling the water circulation process obtains, and output unit is divided into supply user
Fresh water (the most as shown in Figure 2) because the last handling processes such as pH value regulation are the least on the impact of whole water-retention process, can at this
To ignore.Therefore, the dynamic process model of cistern is represented by:
Here t express time, here, StAnd HtRepresent area and the water level of cistern, Q respectivelypFor reverse osmosis water flow,
QoutFor user's water requirement, Ct,outFor the fresh water salinity of output to user, CspObtain permeating water for reverse osmosis controlling the water circulation process
Salinity, for guaranteeing that system operates safety, cistern water level must is fulfilled for Ht,lo<Ht<Ht,up。QpAnd CspValue pass through reverse osmosis
Process model obtains.
Step 3. sets up system operating cost model
According to the rolling reverse osmosis seawater desalting process flow shown in Fig. 1 and real process feature, system operating cost
(operational cost, OC) specifically includes that 1) .RO process operation energy consumption cost (OCEN), predominantly high-pressure pump, booster pump
And the energy consumption of energy-recuperation system.2). seawater taking system and early stage preprocessing process energy consumption cost (OCIP).3). chemistry adds
Add the expense (OC of agentCH), predominantly acid adding, add the expense of the aspect such as antisludging agent and flocculant.4). reverse osmosis membrane renewal cost
(OCME).According to design and ruuning situation, the year turnover rate generally according to about 15-20% calculates.5). upkeep cost (OCMN)。
Comprise the upkeep cost of whole system such as film, high-pressure pump, motor etc..6). labour cost (OCLB)。
The operating cost of sea water water intaking and pretreatment system mainly includes chemical addition agent expense and seawater taking system
With early stage preprocessing process energy consumption cost.According to operating experience, the expense of chemical addition agent is represented by:
OCCH=FUCHQf=0.0225Qf (29)
Seawater taking system is expressed as with early stage preprocessing process energy consumption cost:
Here, PinRepresent the outlet pressure of water pump.QfRepresenting feed rate, PLF represents load factor, PelcRepresent electricity
Power price, ηIPRepresent the efficiency of sea water water pump.
For RO process unit, operating cost mainly include high-pressure pump and booster pump energy consumption cost, film renewal cost and
The energy consumption cost that energy recycle device is saved.High-pressure pump energy consumption cost is expressed as:
PfRepresent high pressure pump outlet pressure, P0Represent high pressure pump inlet pressure, ηHPRepresent the mechanical efficiency of high-pressure pump, ηVFD
Representing the efficiency of converter, its value changes along with frequency change.
The energy consumption cost that energy recycle device is saved is expressed as:
OCPX=Qr·(Pr-Pa)·ηPX·Pelc (32)
QrRepresent the flow of concentrated solution, PrRepresent the pressure head of concentrated solution, PaRepresent strong brine from energy recycle device out time
The pressure waited, ηPXRepresent the efficiency of pressure exchanger.The energy consumption cost of booster pump is then expressed as:
OCBP=Q2·(Pf-Ps)/ηBP·Pelc (33)
Here, Q2Represent the flow by high-pressure pump, PsRepresent the seawater pressure after energy regenerating, ηBPRepresent booster pump
Mechanical efficiency.
So energy consumption of reverse osmosis controlling the water circulation process is represented by:
OCEN=OCHP-OCPX+OCBP (34)
Reverse osmosis membrane renewal cost is represented by:
OCME=PriME×MOD×ζre/365 (35)
Here PriMERepresenting the price of single membrane module, MOD represents the number of membrane module, ξreRepresent the year of membrane module more
Change rate.
The upkeep cost of system is relevant with practical operation situation and system investments situation, can be expressed as under normal circumstances
Routine operation expense is multiplied by the proportionality coefficient of a 3%-5%, as follows:
OCMN=OCNom×CoeMN (36)
Here OCNomThe routine operation expense of expression system, CoeMNRepresent proportionality coefficient.Labour cost is then according to workman's
Wage and number determine, typically constitute from the 8%-15% of routine operation expense, are represented by:
OCLB=OCNom×CoeLB (37)
Here CoeLBRepresent the proportionality coefficient of system convention operating cost shared by labour cost.
Step 4. is according to model above and the target of reduction system operating cost, constructing system operation optimization proposition.
In order to reduce the running cost of system, it is required that the operating cost of system is minimum.Because either water supply load
Or electricity rates or ocean temperature, all have the approximation characteristic with a day as cycle, therefore to optimize conveniently, with one day
The minimum target of operating cost carry out the operation optimization of system.In view of facility constraints and electricity rates situation of change, with 1
Hour regulate performance variable (its feed rate Q for unitfWith feed pressure Pf).Therefore, the object function of optimization can represent
For:
In order to solve the operating cost of each several part in object function, meet water supply quality and want summation device security constraint, excellent
The constraint equation changing proposition is represented by following form:
Equality constraint equation:
Reverse osmosis process model (eqn. (1)-(26)) (38b)
Cistern dynamic process model (eqn. (27)-(28)) (38c)
Operating cost model (eqn. (29)-(37)) (38d)
Inequality constraints:
Water quality retrains: Ct,out≤Cwq,limit (38e)
Antiscale retrains: Cr≤Cr,limit (38f)
Concentration polarization restriction on the parameters: φ≤1.2 (38g)
Equipment pressure confines: Pf,lo≤Pf≤Pf,up (38h)
RO module flow rate retrains: Vf,lo≤Vf≤Vf,up (38i)
Cistern restriction of water level Ht,lo<Ht<Ht,up (38j)
Boundary condition:
Ht(0)-Ht(24)=0 (38k)
Initial and end condition:
Z=0, V=Vf=Qf/(nlWhsp);Pb=Pf;Cb=Cf;
Z=L, V=Vr=Qr/(nlWhsp);Z=L, Pb=Pr;Cb=Cr (38l)
Wherein Cwq,limitRepresent water supply salinity limit value, Cr,limitRepresent the strong brine salinity limit that reverse osmosis process produces
Value, Pf,lo、Vf,loAnd Ht,loRepresent the lower limit of relevant parameter, P respectivelyf,up、Vf,upAnd Ht,upRepresent the upper limit of relevant parameter respectively.
Ht(0) water level at the 0th hour, H are representedt(24) water level at the 24th hour is represented.
The operation optimization proposition formed is solved by step 5..
The optimal problem being made up of formula (38a)-(38l) had both comprised strong nonlinearity algebraic equation, comprised again the differential equation, for
Solve conveniently, use finite element collocation method to be formed by its most discrete non-linear algebraic equation that turns to, form formula (39) and represent
Nonlinear optimal problem.Then use large-scale nonlinear solver that it is optimized to solve, it is thus achieved that optimal objective function
Value and the optimal value of performance variable.With the performance variable optimal value that obtains as setting value, autocontrol method is used to strain mutually
Amount controls at setting value, then the operation optimization of feasible system.Here the finite element collocation method used is conventional method, greatly
Scale nonlinear optimization solver is the solver based on sequential quadratic programming algorithm or interior-point algohnhm.Mentioned here automatically
Control method both can be regulatory PID control method, it is also possible to be advanced control method.
It is embodied as describing to the present invention below in conjunction with embodiment:
The present invention carries out case study to certain rolling reverse osmosis seawater desalination system.This system uses first-stage reverse osmosis stream
Journey, and use PX energy recycle device.Membrane module uses Tao Shi SW30HR series.7 membrane modules of series connection in each pressure vessel,
90 groups of pressure vessels compose in parallel reverse osmosis produced water unit.Cistern is as producing water and the temporary location of water supply, after water quality
Process and realize producing water and the buffering of water supply.The design parameter of system is as shown in table 1, supplies water plan as shown in Figure 3.For solving
This optimal problem, uses 40 finite elements and 3 Radau collocation points to carry out discrete the reverse osmosis module differential equation.To water-retention
The dynamic differential equation of process uses 24 finite elements and 3 Radau collocation points to carry out discrete, the most discrete precision than
Higher, discrete rear optimal problem information is as shown in table 2.To the optimal problem after discretization, use under GMAS24.0 platform based on
The large-scale nonlinear solver IPOPT of interior-point algohnhm is optimized and solves.
Table 1 system feeding condition and cistern parameter information
Feed conditions |
Numerical value |
Input concentration (kg/m3) |
30 |
Feeding temperature (DEG C) |
20 |
Feed pressure (Bar) |
59 |
Charging PH |
5-8 |
Cistern parameter |
Numerical value |
Liquid level area St (m2) |
150 |
The liquid level upper limit (m) |
15 |
Liquid level lower limit (m) |
2 |
Initial concentration (kg/m3) |
0.430 |
Initial liquid height (m) |
4 |
Model information after table 2 discretization
Model Condition |
Numerical value |
Total variable |
70901 |
Equality constraint |
70853 |
Inequality constraints |
25 |
Jacobi non-zero points |
246408 |
Hessian non-zero points |
104450 |
Film finite element number |
40 |
Collocation point |
3 |
Timing departure number |
24 |
Collocation point |
3 |
For guaranteeing the effectiveness of model, use this model that the response rate and salt rejection rate index are calculated, result of calculation
Comparing with real data and ROSA9.0 the data obtained, result is as shown in table 3.As can be seen from Table 3, this model result tool
There is higher accuracy.
Table 3 model data and real data, ROSA9.0 calculate data and compare
Type |
The response rate (%) |
Salt rejection rate (%) |
Real data |
41.6 |
99.37 |
ROSA9.0 data |
42.7 |
99.58 |
Model data |
42.1 |
99.52 |
Below, the present invention will be analyzed in terms of scheme 1 fixing charging parameter, scheme 2 variations in temperature two.Set system
System charging and service condition are as follows: sea water feeding temperature is 20 DEG C;Charging salinity is 30kg/m3;Water supply plan such as Fig. 3 shows, uses
Electricity price lattice such as Fig. 4 shows.In the case optimal problem is solved, and optimum results is compared with routine operation result
Relatively.Here routine operation is defined as CaseA, this behaviour is optimized and is defined as Case B.
Case A does not carry out operation optimization, fixing operation pressure and flow, uses on off control to meet the upper and lower boundary treaty of water level
Bundle and final constraint so that total aquifer yield is equal to water requirement.
In Case B cistern liquid level circle adjustable, reduced by regulation operation pressure, feed rate and cistern liquid level
Total expense cost.
For scheme 1, of substantially equal during in order to ensure the liquid level in the moment when 24 with initial value, use and shut down strategy, and set
Fixed its operates pressure P in runningfFor 64.4bar, operate flow QfFor 1125m3/h.Based on Case A and the meter of Case B
Calculate results contrast and be shown in Table 4 and Fig. 5 a to Fig. 5 d.
Overall expenses and composition situation before and after table 4 optimization
It can be seen from the table, total operation expense is 2.781 ten thousand yuan of every days before optimization, and the most only RO process energy consumption just accounts for
58.1%, add water intaking and preprocessing part, then total energy consumption proportion is 64.8%;And the renewal cost of membrane module is the lowest
In 10%, the most in the highest flight.By the optimization to model, total operating cost can be reduced to 2.039 ten thousand yuan of every days, becomes this section
Province's rate is more than 26%.Wherein the energy consumption of RO module is reduced to 0.9943 ten thousand yuan from 1.6146 ten thousand yuan, is to cause cost to be greatly reduced
Principal element.
In accompanying drawing 5,5a is the pressure changing before and after optimizing, and 5b is the changes in flow rate situation before and after optimizing, and 5c is for producing
The situation of change of water salinity, 5d is then the liquid level situation of change of cistern.Compared to routine operation, optimize operation in operation pressure
Power is the most relatively low with on operation flow, and when the electricity rates shown in Fig. 4 are higher, its flow and pressure reduce bigger.Often
Rule operation completes overall water supply requirement before latter two hour, uses and shuts down strategy so that its flow and pressure are zero.
For scheme 2, the present invention, according to actual temperature change, analyzes sea water feeding temperature behaviour between 16~32 DEG C
Make optimization situation.Here high-pressure pump mechanical efficiency is set as 0.85, and energy recycle device organic efficiency is set as 0.9.The most excellent
Change and the results are shown in Table shown in 5.
Optimum Operation expense and composition situation (DEG C) thereof under the different sea water feeding temperature of table 5
Project |
16 |
18 |
20 |
22 |
24 |
26 |
28 |
30 |
32 |
OCIP |
0.1373 |
0.1357 |
0.1362 |
0.1371 |
0.1335 |
0.1295 |
0.1259 |
0.1281 |
0.1267 |
OCEN |
1.3426 |
1.1322 |
0.9943 |
0.9277 |
0.9236 |
1.001 |
0.9466 |
0.9392 |
0.9395 |
OCCH |
0.2676 |
0.2656 |
0.2636 |
0.2628 |
0.2601 |
0.2591 |
0.2573 |
0.2558 |
0.2545 |
OCME |
0.2170 |
0.2170 |
0.2170 |
0.2170 |
0.2170 |
0.2170 |
0.2170 |
0.2170 |
0.2170 |
OCLB |
0.3200 |
0.3200 |
0.3200 |
0.3200 |
0.3200 |
0.3200 |
0.3200 |
0.3200 |
0.3200 |
OCMN |
0.1080 |
0.1080 |
0.1080 |
0.1080 |
0.1080 |
0.1080 |
0.1080 |
0.1080 |
0.1080 |
OC |
2.392 |
2.178 |
2.039 |
1.973 |
1.962 |
2.035 |
1.978 |
1.968 |
1.966 |
As can be seen from Table 5, temperature has material impact to running cost.Product water cost when 16 DEG C is higher than 32 DEG C
0.426 ten thousand yuan of every days because manually, safeguard and film renewal cost fix, the cost of raising essentially consists in energy consumption cost aspect.This
The rising being because temperature contributes to increasing the penetrating power of water, can obtain and more permeate water under same operation pressure.
As can also be seen from Table 5, total when temperature is more than 24 DEG C operating cost has fluctuated, this is because the raising of temperature also makes
Salinity penetrating power improves, and in order to meet water quality requirement, needs to adjust operation pressure and other parameters, and this makes energy consumption cost occur one
Fixed repeatedly.
Owing to sea water feeding temperature is not only very big along with seasonal variations in real process, within one day, also there is bigger ripple
Dynamic, as shown in following formula (40a) and (40b).Here the operation optimization in the case of constant temperature and alternating temperature is analyzed for.Analysis is divided into
Summer constant temperature STC, alternating temperature STV in summer, constant temperature WTC in winter and tetra-kinds of situations of alternating temperature WTV in winter.Optimum behaviour in the case of these four
The results are shown in Table shown in 6 as Cost Optimization, corresponding optimum manipulation variable curve and performance curve such as Fig. 6 a of desalinization, figure
Shown in 6b and Fig. 6 c.As seen from Table 6, the Optimum Operation expense when 15 DEG C is much higher than the Optimum Operation when 22 DEG C
Expense.Optimum results under summer alternating temperature operating mode, significantly better than constant temperature operating mode, illustrate to change according to operational factor to be optimized
Operation can obtain more preferable effect.
From pressure operation curve (Fig. 6 a), operation pressure is much higher than summer operation pressure in the winter time, and the behaviour in winter
Making flow (Fig. 6 b) and increase ratio than summer the most not quite, after variations in temperature is described, preferential regulation pressure is more suitable.In response rate side
Face (Fig. 6 c), relatively low first 8 hours of electricity price, the response rate of summer condition was higher than winter;And in electricity price relatively
High time interval, although the response rate is greatly lowered, but the response rate of winter condition is higher than summer;This situation
Occur relevant with the dual restriction of membrane module water-yielding capacity in winter and energy consumption.
Optimum Operation expense under table 6 different temperatures parameter
Project |
Temperature (DEG C) |
Optimum Operation expense (ten thousand yuan) |
STC |
T=22 |
2.1031 |
STV |
Equation (40a) |
2.0819 |
WTC |
T=15 |
2.8212 |
WTV |
Equation (40b) |
2.5084 |
Instance analysis shows: 1., compared with the operation of conventional reverse osmosis seawater desalination system, operation optimization in this paper can
System overall operation cost is greatly lowered.Becoming often occurs in actual reverse osmosis seawater desalination system operational factor such as temperature
Dynamic, it is bigger on the impact of Optimum Operation cost and correlation performance parameters;Optimize operation and can effectively reduce operating cost, it is achieved
Water quality and the safe operation of equipment.Optimum results in the case of temperature wide variation again shows that, the system that the present invention is given
Model and solution strategies have the good suitability and robustness.