CN109298690B - Open type circulating water cooling end system optimization control method - Google Patents
Open type circulating water cooling end system optimization control method Download PDFInfo
- Publication number
- CN109298690B CN109298690B CN201811112696.1A CN201811112696A CN109298690B CN 109298690 B CN109298690 B CN 109298690B CN 201811112696 A CN201811112696 A CN 201811112696A CN 109298690 B CN109298690 B CN 109298690B
- Authority
- CN
- China
- Prior art keywords
- circulating water
- circulating
- pressure
- condenser
- pump
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 title claims abstract description 231
- 238000000034 method Methods 0.000 title claims abstract description 38
- 238000001816 cooling Methods 0.000 title claims abstract description 26
- 238000005457 optimization Methods 0.000 title claims abstract description 19
- 238000004364 calculation method Methods 0.000 claims description 25
- 239000000498 cooling water Substances 0.000 claims description 20
- 238000012360 testing method Methods 0.000 claims description 16
- 241000242583 Scyphozoa Species 0.000 claims description 13
- 230000014509 gene expression Effects 0.000 claims description 11
- 238000006243 chemical reaction Methods 0.000 claims description 10
- 238000012937 correction Methods 0.000 claims description 10
- 238000010998 test method Methods 0.000 claims description 9
- 238000010521 absorption reaction Methods 0.000 claims description 7
- 238000011010 flushing procedure Methods 0.000 claims description 3
- 230000007613 environmental effect Effects 0.000 abstract description 4
- 238000012546 transfer Methods 0.000 description 10
- 230000001105 regulatory effect Effects 0.000 description 4
- 238000005259 measurement Methods 0.000 description 3
- 239000003245 coal Substances 0.000 description 2
- 238000004891 communication Methods 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000003203 everyday effect Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000011056 performance test Methods 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 239000013589 supplement Substances 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B19/00—Programme-control systems
- G05B19/02—Programme-control systems electric
- G05B19/418—Total factory control, i.e. centrally controlling a plurality of machines, e.g. direct or distributed numerical control [DNC], flexible manufacturing systems [FMS], integrated manufacturing systems [IMS] or computer integrated manufacturing [CIM]
- G05B19/41865—Total factory control, i.e. centrally controlling a plurality of machines, e.g. direct or distributed numerical control [DNC], flexible manufacturing systems [FMS], integrated manufacturing systems [IMS] or computer integrated manufacturing [CIM] characterised by job scheduling, process planning, material flow
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B2219/00—Program-control systems
- G05B2219/30—Nc systems
- G05B2219/31—From computer integrated manufacturing till monitoring
- G05B2219/31457—Factory remote control, monitoring through internet
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P90/00—Enabling technologies with a potential contribution to greenhouse gas [GHG] emissions mitigation
- Y02P90/02—Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS]
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Quality & Reliability (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Automation & Control Theory (AREA)
- Control Of Positive-Displacement Pumps (AREA)
- Control Of Non-Positive-Displacement Pumps (AREA)
Abstract
The invention relates to the field of circulating water systems of thermal power plants along rivers or coastal areas, in particular to an open type circulating water cooling end system optimization control method. The invention provides an open type circulating water cooling end system optimization control method, aiming at the characteristic that the operation of a coastal (along river) open type circulating water cooling end system is influenced by multiple external environmental factors, comprehensively considering the equipment safety and reliability such as lowest pressure p of a circulating water main pipe through multivariable input such as load, tide level, water inlet temperature and the like and considering the equipment safety and reliabilityminAnd the cold end system economy optimally controls the circulating water pump set, reduces the power consumption of the circulating water pump, and further effectively excavates the energy-saving potential of the cold end system of the coastal (along river) thermal power plant.
Description
Technical Field
The invention relates to the field of circulating water systems of thermal power plants along rivers or coastal areas, in particular to an open type circulating water cooling end system optimization control method, which is used for deep energy-saving optimization and operation of a variable-frequency circulating water pump unit.
Background
The cold end system of the large-scale thermal power plant is an important component of a thermal power generating unit, provides a stable cold source for thermal circulation, takes away almost half of heat generated by coal combustion through circulating cooling water, and has huge energy-saving potential because a circulating water pump consumes great power in work, but the open circulating water cold end system is greatly influenced by environmental factors, and has numerous factors influencing the economy of the cold end system, and the representation of the influence on the economy of the unit is not obvious relative to the hot end parameters of the unit, such as main steam temperature and reheat steam temperature, so that the energy-saving potential of the unit is easily ignored by operators. In addition, the open circulating water cooling end system provides a cooling water source for closed water and auxiliary machines of the unit, and the operation state of the system also influences the safety and reliability of the operation of corresponding equipment, so that the optimal operation mode of cold end system equipment needs to comprehensively consider the factors of economy and equipment reliability. At present, each unit of a domestic thermal power plant is generally provided with 2-3 circulating water pumps, and each circulating water pump has two running modes of high speed and low speed; the high-speed/low-speed state of the circulating water pump needs manual switching, a communication valve is arranged on a circulating water main pipe between units, and the circulating water pump group has a plurality of operation combination modes on the basis of the configuration, for example, 12 operation combination modes are provided for cold end systems of 4 high-speed/low-speed circulating water pumps configured for 2 units of units; furthermore, some power plant circulating water pumps are provided with frequency conversion devices, the circulating water pump combination does not need to be manually switched, and the use is more convenient.
Most of the economic operation of the existing cold end system focuses on the energy-saving potential of the cold end system of the unit under different circulating water inlet temperatures (or weather states) and loads by establishing a condenser variable working condition model, a low-pressure cylinder micro-increase output and exhaust pressure characteristic curve, then comprehensively considering the power consumption of a circulating water pump and the output change of the low-pressure cylinder caused by the vacuum change of the condenser to obtain the optimal operation vacuum of the condenser, and finally giving the optimal pump-following operation combination or the optimal operation rotating speed. For open circulating water systems along the sea, factors influencing cold end systems such as tide level and circulating water temperature are numerous, particularly, the tide level of a water source in the open circulating water systems has great influence on the flow rate of a circulating water pipeline and the power consumption of a circulating water pump, and the tide level and the low tide level change every day by 7-8 meters. The existing cold end system control method which takes the weather state (or the inlet water temperature of circulating water) as a single input element, completely takes the unit economy as an optimization target and does not consider the operation reliability of other equipment is not suitable for the open-type circulating cold end system along the coast.
Disclosure of Invention
The invention provides an open-type circulating water cooling end system optimization control method, aiming to solve the technical problems that the weather state (or the inlet water temperature of circulating water) is taken as a single input element, the unit economy is completely taken as an optimization target, the influence of the water source tide level on the power consumption of a circulating water pump is ignored, the operation reliability of other equipment is not considered, and the like in the conventional coastal open-type circulating cold end system control method.
The technical scheme adopted by the invention for solving the technical problem is as follows: an open cycle water-cooling end system optimization control method comprises the following steps in sequence:
firstly, establishing a cold end system operation process and a minimum pressure p of a circulating water main pipeminDuring the operation process, the pressure of the circulating water main pipe is ensured to be always greater than the minimum pressure p of the circulating water main pipe through the opening of a butterfly valve at the outlet of the circulating water main pipemin；
Secondly, establishing a relation formula of a head (H) -flow (G), a relation formula of the head (H) -power (P) and a relation formula of the head (H) -efficiency (eta) of a circulating pump group of the circulating water pumps at different rotating speeds;
thirdly, establishing a relational expression between the pressure (p) of the circulating water main pipe and the flow (Q) of the circulating water main pipe when the butterfly valve of the circulating water outlet is fully opened, and measuring a plurality of test points p through tests1，p2… … -hour flow Q of main circulating water pipe1，Q2… …, then fitting to obtain the relation p ═ p (q);
fourthly, when the input variables of tide level h, the circulating pump rotating speed r and the circulating pump number n are given, the minimum pressure p of the comprehensive circulating water main pipeminAnd the flow Q of the circulating water main pipe and the power consumption p of the circulating pump combination of the cold end system at the moment are calculated through iterative calculationn；
Fifthly, establishing different loads p through a test modeel0The load P of the unitelAnd back pressure p of condensercRelation P ofel＝Pel0/(1+f(pc-pc0) /100) and relation HR of heat consumption rate and load of unit0＝HR(pel0) The pel0 is a load when the steam inlet parameter and the back pressure of the thermodynamic cycle are rated values, and pc0 is a rated back pressure value;
sixthly, establishing a variable working condition model of the condenser, and setting the flow Q of circulating water entering the condensercAnd the inlet temperature t of the circulating waterw1Thermal load Tl of condensercThen, the back pressure p of the condenser is obtainedcThe relation of (a), the circulating water flow rate QcSubtracting the cooling water and the open water flow of the vacuum pump from the flow of the circulating water main pipe of the single unit;
seventhly, obtaining the tide level h and the inlet water temperature t of the circulating water at corresponding input variables through iterative calculation according to the relational expressions given in the fourth step, the fifth step and the sixth stepw1The number n and the rotation speed r of the pump units, and the load P of the unitelTime condenser back pressure pcThermodynamic cycle heat absorption capacity TlabAnd deducting the net output power Pel of the power consumption of the circulating water pump and other service powernetAnd the power supply heat consumption rate HR of the unitnet；
The eighth step, the DCS system is executedTidal level h and load P collected by the systemelInlet temperature t of circulating waterw1And as input variables, comparing the power supply and heat consumption rates of the units under different tracking pump numbers n and rotating speed r states, obtaining the optimal circulating water pump combination and rotating speed by taking the minimum power supply and heat consumption rate as a target, issuing a rotating speed instruction to a corresponding frequency conversion unit through a unit DCS (distributed control system), and changing the rotating speed of the circulating water pump so as to realize closed-loop control.
Aiming at the characteristic that the operation of a cold end system of open circulating water at the coast (along the river) is influenced by multiple external environmental factors, the optimal control method of the circulating water cooling end system comprehensively considers the safety and reliability of equipment such as the minimum pressure p of a circulating water main pipe through multivariable input such as load, tide level, inlet water temperature and the likeminAnd the cold end system economy optimally controls the circulating water pump set, reduces the power consumption of the circulating water pump, and further effectively excavates the energy-saving potential of the cold end system of the coastal (along river) thermal power plant. In addition, the open circulating water cold end system matched with the system is configured as follows: the circulating pump set is a variable-rotating-speed circulating water pump, and the related speed regulating system can be connected to a unit DCS control system and issues rotating speed instructions through the control system; each steam turbine set can be provided with 2-3 variable-speed circulating water pump sets, and a circulating water pipeline of each set can be connected with a circulating water pipeline of an adjacent set through a communication valve, so that the main control operation of a circulating water system is realized; a butterfly valve is arranged at the tail end of a circulating water main pipe (at the outlet of a condenser) to adjust the pressure of the circulating water main pipe, and the method is the prior art in the field.
As a further improvement and supplement to the above technical solution, the present invention adopts the following technical measures: in the first step, the minimum pressure p of the circulating water main pipe is determined by a field test methodminThe minimum pressure p of the circulating water main pipeminThe minimum cooling requirement and the secondary filter screen flushing capacity of a closed water system and the cooling water of the vacuum pump can be ensured. Open water provides cooling water for closed water and a vacuum pump, and the pressure of the circulating water main pipe is ensured to be always greater than the minimum pressure p of the circulating water main pipe through the opening of a butterfly valve at the outlet of the circulating water main pipe in the actual operation processmin。
In the second step, the lowest rotation of the variable-frequency circulating water pump is carried outSpeed rminAnd maximum rotational speed rmaxA plurality of test points r are set at regular intervals of rotation speed (10-20 r/min)1,r2,r3… …, measuring the relation G (G) of the head (H) -flow (G) of the circulating water pump at the several rotating speed points by a field test method1，H)，G＝G(r2H) … …; head (H) -power (P) relation P ═ P (r)1，H)，P＝P(r2H) … …, lift (H) -efficiency of pump group (η) relation η - η (r)1，H)，η＝η(r2H) … …; at a set rotation speed point r1、r2The relation of the lift (H) -flow (G), the relation of the lift (H) -power (P) and the relation of the lift (H) -efficiency (η) of the circulating water pump at the rotating speed r can be calculated by the similar law of the circulating water pump to obtain:
at a set rotation speed point r1、r2The head-flow relation at the rotating speed r
Head (H) -efficiency (η) relationship
Head (H) -power (P) relation
The above-mentionedG、ηIs a correction factor.
The correction coefficientG、ηWhere r is r1Time of flightG(r1，H)＝1，η(r1，H)＝1；
When r is r2Time of flight
Two measuring points r1，r2And the correction coefficients at other rotating speeds r are calculated by a linear interpolation method to obtain:
in the fourth step, a pressure p of a circulating water main pipe is set0Initial value is set to pminThe lift H of the circulating water pump at the moment is obtained by combining the input variable tide level H, the flow rate G (r, H) and the power P (r, H) of 1 circulating water pump at the moment are obtained by the relational expression established in the second step, and then the flow rate Q of a main circulating water pipe is n × G (r, H) and the total power P of a circulating pump combination are obtainednN × P (r, H), and calculating the pressure P of the circulating header at the flow rate of the circulating water according to the relation formula established in the third step1If p is1Is less than pminAssuming the pressure of the circulating jellyfish pipe to be p0Is pminSubstituting into the above steps to calculate if p1Greater than pminThen, the pressure of the circulating jellyfish pipe is assumed to be p0Is set to p1Substituting the above steps to perform iterative calculation until p1And p0And when the difference is less than 0.001, the result after the iteration is finished is the pressure, the flow and the power of the circulating pump set of the circulating jellyfish under the given boundary condition.
In the seventh step, the unit load is PelFirstly, the back pressure p of the condenser is setc1Determining the back pressure as a desired value p from said fifth stepc0Load P of rated thermodynamic cycle corresponding to the thermodynamic cycleel0And heat rate HR0(ii) a The thermal load Tl of the thermodynamic cycle condenserc＝HR0×Pel0-PelThermodynamic cycle heat absorption of Tlab＝HR0×Pel0And according to the condenser variable working condition model established in the sixth step, setting the inlet water temperature t of the circulating waterw1And the flow Q of the circulating water entering the condensercIn time, the back pressure p of the condenser is obtainedc2Presume the condenser back pressure to be pc1Is set to pc2Repeatedly carrying out iterative calculation until the difference value between the two is less than 0.001, and finishing the iterative calculation to obtain the condenser pressure pcCondenser pressure over given boundary conditions.
The invention provides an open type circulating water cooling end system optimization control method which comprehensively considers the thermodynamic cycle economy and the equipment safety and reliability, changes the operation mode of a cold end system according to external environmental factors such as load, tide level and inlet water temperature in real time, reduces the power consumption of a circulating water pump and exploits the energy-saving potential of the cold end system.
Drawings
FIG. 1: the invention relates to a control method schematic diagram.
FIG. 2: the invention relates to a configuration schematic diagram of an open cycle water cooling end system.
In the figure: 1. frequency conversion circulating water pump package A, 2, frequency conversion circulating water pump package B, 3, frequency conversion circulating water pump package C, 4, frequency conversion circulating water pump package D, 5, circulating water main pipe contact valve, 6, circulating water main pipe outlet butterfly valve.
Detailed Description
The invention is further described with reference to the following description and embodiments in conjunction with the accompanying drawings.
As shown in fig. 1-2, an open circulating water cooling system optimization control method is disclosed, wherein the open circulating water cooling system configuration related to the control method in this embodiment is as shown in fig. 2, each generator set is configured with 4 variable-speed circulating water pump groups according to the circulating cooling water requirement of a certain thermal power plant, and the 4 variable-speed circulating water pump groups are respectively a variable-frequency circulating water pump group a1, a variable-frequency circulating water pump group B2, a variable-frequency circulating water pump group C3 and a variable-frequency circulating water pump group D4; each variable-frequency circulating water pump set is a variable-rotating-speed circulating water pump and is provided with a motor and a corresponding circulating water pump, the rotating speed of the circulating water pump is changed by adding a variable-frequency device at the motor end or adding a speed regulating device such as a permanent magnet speed regulating device between the motor and the circulating water pump, the related variable-frequency device or the related permanent magnet speed regulating device is connected to a DCS control system of the unit, and a rotating speed instruction is issued by the control system; the circulating water pipeline of each variable-frequency circulating water pump group is connected with the circulating water pipeline of the adjacent variable-frequency circulating water pump group through a circulating water main pipe connecting valve 5, so that the main pipe system of the circulating water system is operated; a circulating water main pipe outlet butterfly valve 6 is arranged at the tail end (the outlet of the condenser) of the circulating water main pipe, and the resistance characteristic of the circulating water main pipe can be changed by adjusting the opening of the butterfly valve in use so as to adjust the pressure of the circulating water main pipe; in the figure, closed water cooling water and vacuum pump cooling water are cooling water supplied to closed water and cooling water supplied to a vacuum pump, respectively, which is the prior art.
The control method comprises the following steps which are carried out in sequence:
firstly, establishing a cold end system operation process and a minimum pressure p of a circulating water main pipeminDuring the operation process, the pressure of the circulating water main pipe is ensured to be always greater than the minimum pressure p of the circulating water main pipe through the opening of a butterfly valve at the outlet of the circulating water main pipeminIn particular to the minimum pressure p of a main pipe of the circulating waterminThe minimum cooling requirement and the secondary filter screen flushing capacity of a closed water system and the cooling water of a vacuum pump can be ensured, and when the pressure of a circulating jellyfish pipe in the operation process is lower than the minimum pressure pminWhen the pressure of the circulating water main pipe is equal to p, the butterfly valve at the outlet of the circulating water main pipe, namely the butterfly valve 6 at the outlet of the circulating water main pipe, is turned down until the pressure of the circulating water main pipe is equal to pminAnd then shut down. When the pressure of the circulating jellyfish pipe is higher than the lowest pressure p in the running processminWhen the pressure of the main pipe of the circulating water is equal to p, the butterfly valve is opened greatlyminWhen the outlet butterfly valve is fully opened;
lowest pressure p of circulating water main pipeminThe relation between the cooling flow of the open cooling water and the vacuum pump of the power plant and the pressure of the circulating water main pipe measured by the high-precision flowmeter is shown in the table, and the table shows that when the pressure of the circulating water main pipe is lower than 160kPa, the cooling water of the open cooling water and the vacuum pump has the tendency of accelerating to slide downwards, so that the minimum pressure p of the circulating water main pipe is determinedminDetermined as 160kPa
| Pressure of circulating jellyfish pipe (Absolute pressure, kPa) | 187.5 | 156.1 | 150 |
| Open water flow (t/h) | 4200 | 3900 | 3708 |
| Vacuum pump cooling water flow t/h) | 190 | 178 | 175 |
Secondly, establishing a relation among a head (H) -flow (G), a head (H) -power (P) and a head (H) -efficiency (η) of the circulating water pump at different rotating speeds, and determining a relation (characteristic curve) among the head (H) -flow (G), the head (H) -power (P) and the head (H) -efficiency (η) of the circulating water pump at a set rotating speed point by a field test method, particularly the lowest rotating speed r of the variable-frequency circulating water pumpminAnd maximum rotational speed rmaxA plurality of test points r are set at regular intervals of rotation speed (10-20 r/min)1,r2,r3… …, and measuring the relation G (H) -flow (G) of the circulating water pump at the several rotating speed points by using a field test method1，H)，G＝G(r2H) … …; head (H) -power (P) relation P ═ P (r)1，H)，P＝P(r2H) … …, lift (H) -efficiency of pump group (η) relation η - η (r)1，H)，η＝η(r2H) … …; the circulating pump efficiency obtained by calculation comprises the motor, pump body efficiency and coupling transmission efficiency; at a set rotation speed point r1、r2The relation between the lift (H) and the flow (G) of the circulating water pump at the rotating speed r, the relation between the lift (H) and the power (P), and the lift: (H) -the efficiency relation of the tracking pump group (η) can be calculated by the similar law of the circulating water pump:
head-flow relation between set rotational speed points r1, r2
Head (H) -efficiency (η) relationship
Head (H) -power (P) relation
The correction coefficientG、ηWhere r is r1Time of flightG(r1，H)＝1，η(r1，H)＝1；
When r is r2Time of flight
Two measuring points r1，r2And the correction coefficients at other rotating speeds r are calculated by a linear interpolation method to obtain:
G、ηin order to correct the coefficients, the calculated values and the actual values will deviate to some extent under the influence of the similar law model and the variation of the motor efficiency, for which the invention introducesG、ηMaking corrections to greatly improve the accuracy of the calculations
Thirdly, establishing full-open time circulation of a butterfly valve of a circulating water outletThe method comprises the following steps of determining a pipeline resistance characteristic curve by a field test method, specifically, measuring a plurality of test points p by the field test method1，p2… … -hour flow Q of main circulating water pipe1，Q2… …, and then fitting to obtain the relation p ═ p (q). The circulating water flow measurement can be obtained by fitting a comprehensive condenser heat balance calculation value and a high-precision ultrasonic flowmeter measurement value, so that the flow measurement accuracy can be improved; and thirdly, because the pressure head of the outlet of the circulating water pipeline is unchanged, when the opening of the circulating water outlet valve of the condenser is 100%, the flow Q of the circulating water pipeline can be regarded as a single function of the pressure p of the circulating water main pipe, and based on the measured data, a relational expression of the pressure p of the circulating water main pipe and the flow Q of the circulating water can be fitted.
Fourthly, when the input variables of tide level h, the circulating pump rotating speed r and the circulating pump number n are given, the minimum pressure p of the comprehensive circulating water main pipeminAnd the flow Q of the circulating water main pipe and the power consumption p of the circulating pump combination of the cold end system at the moment are calculated through iterative calculationn(ii) a In the fourth step, a pressure p of a circulating water main pipe is set0Initial value is set to pminThe lift H of the circulating water pump at the moment is obtained by combining the input variable tide level H, the flow rate G (r, H) and the power P (r, H) of 1 circulating water pump at the moment are obtained by the relational expression established in the second step, and then the flow rate Q of a main circulating water pipe is n × G (r, H) and the total power P of a circulating pump combination are obtainednN × P (r, H), and calculating the pressure P of the circulating header at the flow rate of the circulating water according to the relation formula established in the third step1If p is1Is less than pminAssuming the pressure of the circulating jellyfish pipe to be p0Is pminSubstituting into the above steps to calculate if p1Greater than pminThen, the pressure of the circulating jellyfish pipe is assumed to be p0Is set to p1Substituting the above steps to perform iterative calculation until p1And p0And when the difference is less than 0.001, the result after the iteration is finished is the pressure, the flow and the power of the circulating pump set of the circulating jellyfish under the given boundary condition. Step four shows that on the basis of the known resistance characteristic of the circulating water pipeline and the characteristic of the circulating water pump, the resistance characteristic is calculated by an iterative methodThe flow Q of the circulating water pipeline and the power consumption P of the circulating pump group are obtained when the rotating speed r of the circulating pump, the number n of the running stations and the tide level h are knownn。
Fifthly, establishing different loads p through a test modeel0The load P of the unitelAnd back pressure p of condensercRelation P ofel＝Pel0/(1+f(pc-pc0) /100) and relation HR of heat consumption rate and load of unit0＝HR(pel0) Said p isel0Load when the inlet steam parameter and back pressure of the thermodynamic cycle are rated values, pc0The nominal back pressure value (the design value, from which the actual operation deviates a little). Fifthly, the relational expression between the heat rate and the load of the unit can be obtained by fitting through a conventional thermal performance test; unit load P at different load pointselAnd back pressure pcThe relation is generally called as the low pressure cylinder micro-increase force characteristic and is related to the low pressure cylinder model selection, the relation manufacturer gives a design value, but in order to accurately express the actual state on site, the relation can be obtained by fitting through a site test method, a plurality of load points (100% THA, 75% THA and 50% THA) can be selected during the test, other parameters except the back pressure of the thermodynamic cycle are corrected to the same value, and the unit load P at the load points can be obtained by fittingelAnd back pressure pcThe relationship of (a) and (b) is such that the low cylinder micro-boost force output characteristic for other loads between the two test load points is obtained by linear interpolation.
Sixthly, establishing a variable working condition model of the condenser, and setting the flow Q of circulating water entering the condensercAnd the inlet temperature t of the circulating waterw1Thermal load Tl of condensercThen, the back pressure p of the condenser is obtainedcThe relation of (a), the circulating water flow rate QcAnd subtracting the cooling water and the open water flow of the vacuum pump from the flow of the circulating water main pipe of the single unit. And step six, a condenser variable working condition model: because the steam exhaust of the low-pressure cylinder is in a saturated state; condenser pressure pcThe condenser pressure p is in one-to-one correspondence with the exhaust temperaturecCan be controlled by the exhaust temperature tcCalculated by a water vapor formula. Exhaust temperature t of low-pressure cylindercCan be calculated from the following formula:
tc＝tw1+Δt+t,Δt＝tw2-tw1,t＝tc-tw2
tc: low pressure cylinder exhaust temperature, deg.C; t is tw1: the inlet temperature of circulating water is at DEG C; t is tw2The temperature of the circulating water is controlled at the temperature of △ t, and the temperature of the condenser is controlled at the temperature of the end difference of the condenser;
wherein the temperature rise delta t of the circulating water and the end difference t of the condenser can be calculated by the following formula:
Tlccondenser heat load, MJ/h; and Qc: the flow rate t/h of the circulating water entering the condenser is the flow rate Q of a main pipe of the circulating water minus the flow rate of cooling water of the open type cooling water and the vacuum pump; k: total heat transfer coefficient of condenser, kJ/(m)2H. degree.C.); f: cooling area of condenser, m2；
The heat transfer calculation K of the condenser is complex, a simplified calculation method is often adopted in engineering calculation, the whole cooling area is considered to have an average heat transfer coefficient, namely the total heat transfer coefficient of the condenser, the total heat transfer coefficient calculation methods are many, but empirical formulas obtained according to experiments are more representative, the former Sulian Coleman formula BT and the American heat transfer society formula HEI are available, and some coefficients in the calculation formulas are inconsistent with the conditions of the tube bundle arrangement of the tested condenser, the scaling degree of tubes, the cohesive air volume of the condenser and the like, so that some deviations exist between the heat transfer coefficient calculated theoretically and the test heat transfer coefficient; in order to correct the deviation factor, the heat transfer coefficient K of the condenser calculated according to the formulacalAnd actually measuring the heat transfer coefficient K of the condensertestThe error of (2) is corrected by introducing a deviation correction coefficient mu into a calculation formula, wherein mu is Ktest/Kcal(ii) a The accuracy of the condenser variable working condition calculation model is further improved.
Seventhly, obtaining corresponding outputs through iterative computation according to the relational expressions given in the fourth step, the fifth step and the sixth stepVariable input tidal level h and circulating water inlet temperature tw1The number n and the rotation speed r of the pump units, and the load p of the unitelTime condenser back pressure pcThermodynamic cycle heat absorption capacity TlabAnd deducting the net output power Pel of the power consumption of the circulating water pump and other service powernetAnd the power supply heat consumption rate HR of the unitnet. In the seventh step, the load of the unit is PelFirstly, the back pressure p of the condenser is setc1Determining the back pressure as a desired value p from said fifth stepc0Load P of rated thermodynamic cycle corresponding to the thermodynamic cycleel0And heat rate HR0(ii) a The thermal load Tl of the thermodynamic cycle condenserc＝HR0×Pel0-PelThermodynamic cycle heat absorption of Tlab＝HR0×Pel0And according to the condenser variable working condition model established in the sixth step, setting the inlet water temperature t of the circulating waterw1And the flow Q of the circulating water entering the condensercIn time, the back pressure p of the condenser is obtainedc2Presume the condenser back pressure to be pc1Is set to pc2Repeatedly carrying out iterative calculation until the difference value between the two is less than 0.001, and finishing the iterative calculation to obtain the condenser pressure pcCondenser pressure over given boundary conditions. In the seventh step, through the relational expression established in the fourth, fifth and sixth steps, the known rotation speed r of the circulating pump, the number n of the circulating pumps, the sea level h and the unit load P are determinedelAnd the inlet temperature t of the circulating waterw1According to the iterative method described in step 7, the condenser pressure p is usedcThe condenser pressure under the boundary condition and the heat absorption Tl of the thermodynamic cycle can be obtained by calculation for intermediate iteration variablesabThe power supply heat rate under the boundary condition can be calculated by the following formula:
taking a certain working condition of a certain open type circulating water system as an example, the circulating pump rotating speed r is 370r/min, n is 2, h is 9m, and t isw1＝20℃，Pel660MW, iterateThe procedure is shown in the following table:
eighthly, the tide level h and the load P collected by the DCS are processedelInlet temperature t of circulating waterw1And as input variables, comparing the power supply and heat consumption rates of the units under different tracking pump numbers n and rotating speed r states, obtaining the optimal circulating water pump combination and rotating speed by taking the minimum power supply and heat consumption rate as a target, issuing a rotating speed instruction to a corresponding frequency conversion unit through a unit DCS (distributed control system), and changing the rotating speed of the circulating water pump so as to realize closed-loop control. In step eight, the tide level h and the unit load PelAnd the inlet temperature t of the circulating waterw1Inputting data collected by the DCS system as input variables into an optimization model, calculating power supply and heat consumption rates corresponding to different numbers of circulating pumps n and rotating speeds r according to the method in the seventh step, outputting optimization results of the numbers of circulating pumps n and the rotating speeds r corresponding to the working conditions with the minimum power supply coal consumption rates through comparison, calculating the comparison through external program programming, transmitting the results to the DCS control system, inputting the results to a circulating pump frequency conversion unit (namely a frequency conversion device at the front end of a motor) by the DCS system, adjusting the rotating speeds of the circulating pumps and starting and stopping the corresponding circulating pumps, and achieving the purpose of closed-loop control.
Claims (6)
1. An open cycle water-cooling end system optimization control method comprises the following steps in sequence:
firstly, establishing a cold end system operation process and a minimum pressure p of a circulating water main pipeminDuring the operation process, the pressure of the circulating water main pipe is ensured to be always greater than the minimum pressure p of the circulating water main pipe through the opening of a butterfly valve at the outlet of the circulating water main pipemin；
Secondly, establishing a relation formula of a head (H) -flow (G), a relation formula of the head (H) -power (P) and a relation formula of the head (H) -efficiency (eta) of a circulating pump group of the circulating water pumps at different rotating speeds;
thirdly, establishing a relational expression between the pressure (p) of the circulating water main pipe and the flow (Q) of the circulating water main pipe when the butterfly valve of the circulating water outlet is fully opened, and measuring if the pressure (p) is fully opened through testsDry number test point p1，p2… … -hour flow Q of main circulating water pipe1，Q2… …, then fitting to obtain the relation p ═ p (q);
fourthly, when the input variables of tide level h, the circulating pump rotating speed r and the circulating pump number n are given, the minimum pressure p of the comprehensive circulating water main pipeminAnd the flow Q of the circulating water main pipe and the power consumption p of the circulating pump combination of the cold end system at the moment are calculated through iterative calculationn；
Fifthly, establishing different loads p through a test modeel0The load P of the unitelAnd back pressure p of condensercRelation P ofel＝Pel0/(1+f(pc-pc0) /100) and relation HR of heat consumption rate and load of unit0＝HR(Pel0) Said p isel0Load when the inlet steam parameter and back pressure of the thermodynamic cycle are rated values, pc0Is a rated back pressure value;
sixthly, establishing a variable working condition model of the condenser, and setting the flow Q of circulating water entering the condensercAnd the inlet temperature t of the circulating waterw1Thermal load Tl of condensercThen, the back pressure p of the condenser is obtainedcThe relation of (a), the circulating water flow rate QcSubtracting the cooling water and the open water flow of the vacuum pump from the flow of the circulating water main pipe of the single unit;
seventhly, obtaining the tide level h and the inlet water temperature t of the circulating water at corresponding input variables through iterative calculation according to the relational expressions given in the fourth step, the fifth step and the sixth stepw1The number n and the rotation speed r of the pump units, and the load p of the unitelTime condenser back pressure pcThermodynamic cycle heat absorption capacity TlabAnd deducting the net output power Pel of the power consumption of the circulating water pump and other service powernetAnd the power supply heat consumption rate HR of the unitnet；
Eighthly, the tide level h and the load P collected by the DCS are processedelInlet temperature t of circulating waterw1As input variables, comparing the power supply and heat consumption rates of the units under the states of different numbers n of circulating pumps and the rotating speed r, obtaining the optimal circulating water pump combination and rotating speed by taking the minimum power supply and heat consumption rate as a target, and passing through a DCS (distributed control System) of the unitsAnd a rotating speed instruction is issued to the corresponding frequency conversion unit in a unified mode, and the rotating speed of the circulating water pump is changed so as to realize closed-loop control.
2. The open cycle water-cooling end system optimization control method according to claim 1, wherein the minimum pressure p of the circulating water main pipe is determined by a field test method in the first stepminThe minimum pressure p of the circulating water main pipeminThe minimum cooling requirement and the secondary filter screen flushing capacity of a closed water system and the cooling water of the vacuum pump can be ensured.
3. The open cycle water-cooling end system optimization control method according to claim 1, wherein in the second step, the minimum rotating speed r of the variable frequency circulating water pump isminAnd maximum rotational speed rmaxA plurality of test points r are set at regular intervals of rotation speed (10-20 r/min)1,r2,r3… …, measuring the relation G (G) of the head (H) -flow (G) of the circulating water pump at the several rotating speed points by a field test method1，H)，G＝G(r2H) … …; head (H) -power (P) relation P ═ P (r)1，H)，P＝P(r2H) … …, lift (H) -efficiency of pump group (η) relation η - η (r)1，H)，η＝η(r2H) … …; at a set rotation speed point r1、r2The relation of the lift (H) -flow (G), the lift (H) -power (P) and the efficiency (η) of the lift (H) -circulating pump group at the set rotating speed r can be calculated by the similarity law of the circulating water pump1、r2The head-flow relation at the rotating speed r is
Head (H) -efficiency (η) relationship
Head (H) -power (P) relation
The above-mentionedG、ηIs a correction factor.
4. The open cycle water-cooling end system optimization control method of claim 3, wherein the correction factorG、ηWhere r is r1Time of flightG(r1，H)＝1，η(r1，H)＝1；
When r is r2Time of flight
Two measuring points r1，r2And the correction coefficients at other rotating speeds r are calculated by a linear interpolation method to obtain:
5. the open cycle water-cooling end system optimization control method according to claim 4, wherein the fourth step is to set a pressure p of a circulating water main pipe0Initial value is set to pminCombining with input variable tide level H, the lift H of the circulating water pump at the moment is obtained, the flow rate G (r, H) and the power P (r, H) of 1 circulating water pump at the moment are obtained by the relational expression established in the second step, and then the flow rate Q of the circulating water main pipe is n × G (r, H) and the total power P of the circulating pump combination are obtainednN × P (r, H);
calculating the pressure p of the circulating jellyfish pipe under the circulating water flow according to the relation established in the third step1If p is1Is less than pminAssuming the pressure of the circulating jellyfish pipe to be p0Is pminSubstituting into the above steps to calculate if p1Greater than pminThen, the pressure of the circulating jellyfish pipe is assumed to be p0Is set to p1Substituting the above steps to perform iterative calculation until p1And p0And when the difference is less than 0.001, the result after the iteration is finished is the pressure, the flow and the power of the circulating pump set of the circulating jellyfish under the given boundary condition.
6. The optimal control method for the circulating water cooling end system according to claim 1, wherein the unit load in the seventh step is PelFirstly, the back pressure p of the condenser is setc1Determining the back pressure as a desired value p from said fifth stepc0Load P of rated thermodynamic cycle corresponding to the thermodynamic cycleel0And heat rate HR0(ii) a The thermal load Tl of the thermodynamic cycle condenserc＝HR0×Pel0-PelThermodynamic cycle heat absorption of Tlab＝HR0×Pel0And according to the condenser variable working condition model established in the sixth step, setting the inlet water temperature t of the circulating waterw1And the flow Q of the circulating water entering the condensercIn time, the back pressure p of the condenser is obtainedc2Presume the condenser back pressure to be pc1Is set to pc2Repeatedly carrying out iterative calculation until the difference value between the two is less than 0.001, and finishing the iterative calculation to obtain the condenser pressure pcCondenser pressure over given boundary conditions.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811112696.1A CN109298690B (en) | 2018-09-25 | 2018-09-25 | Open type circulating water cooling end system optimization control method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811112696.1A CN109298690B (en) | 2018-09-25 | 2018-09-25 | Open type circulating water cooling end system optimization control method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109298690A CN109298690A (en) | 2019-02-01 |
| CN109298690B true CN109298690B (en) | 2020-09-01 |
Family
ID=65163913
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201811112696.1A Active CN109298690B (en) | 2018-09-25 | 2018-09-25 | Open type circulating water cooling end system optimization control method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109298690B (en) |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110111916A (en) * | 2019-03-29 | 2019-08-09 | 中国船舶重工集团公司第七一九研究所 | Marine PWR circulation and its flow control methods with flow control function |
| CN110032155A (en) * | 2019-04-12 | 2019-07-19 | 华能国际电力股份有限公司 | Seawater direct current cooling water system operation optimization guidance system of thermal power plant |
| CN110298492B (en) * | 2019-06-06 | 2021-08-03 | 浙江浙能技术研究院有限公司 | Method for evaluating energy-saving reconstruction benefits of condenser vacuumizing system |
| CN110454373B (en) * | 2019-08-20 | 2020-09-15 | 华能国际电力股份有限公司 | Optimized operation method for variable frequency pump of seawater direct-current cooling water system |
| CN111352400B (en) * | 2020-03-13 | 2021-05-07 | 中国大唐集团科学技术研究院有限公司华东电力试验研究院 | Heat supply unit sliding pressure operation optimization method and sliding pressure operation control system |
| CN112069677A (en) * | 2020-09-03 | 2020-12-11 | 润电能源科学技术有限公司 | Method, device and equipment for determining running mode of cold end circulating pump of power plant and storage medium |
| CN112348414B (en) * | 2020-12-01 | 2023-12-15 | 浙江浙能技术研究院有限公司 | Load distribution adjustment method based on circulating water system operation mode |
| CN113806885B (en) * | 2021-09-06 | 2023-11-03 | 苏州西热节能环保技术有限公司 | Method for determining optimization curve of cold end of steam turbine based on seawater direct-supply condenser |
| CN113864013B (en) * | 2021-10-09 | 2023-07-14 | 中国大唐集团科学技术研究院有限公司西北电力试验研究院 | Cold end optimization method for all-condition of wet-cooling thermal power unit |
| CN114017150B (en) * | 2021-11-05 | 2023-03-17 | 西安热工研究院有限公司 | Multi-circulating-pump coordinated dispatching control system and method for gas-steam combined cycle unit |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06185765A (en) * | 1992-12-18 | 1994-07-08 | Toshiba Corp | Cooling facility in power plant |
| JP2002162087A (en) * | 2000-11-22 | 2002-06-07 | Dai-Dan Co Ltd | Variable flow control system for exhaust heat recovery and heat source |
| CN103244433A (en) * | 2013-05-09 | 2013-08-14 | 国家电网公司 | Operation optimizing and monitoring method for variable-frequency circulating water pump of power plant |
| CN106371314A (en) * | 2016-09-29 | 2017-02-01 | 国电科学技术研究院 | Cooling working medium throttling regulation-based load control system and variable working condition calculation method |
| CN107368680A (en) * | 2017-07-14 | 2017-11-21 | 中国华能集团清洁能源技术研究院有限公司 | A kind of steam turbine optimum vacuum real-time computing technique |
| CN107917089A (en) * | 2017-11-17 | 2018-04-17 | 上海交通大学 | Water circulating pump pumps leaf aperture optimal regulation method |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3603145B2 (en) * | 1998-07-28 | 2004-12-22 | 株式会社日立製作所 | Operating device for seawater pump |
| JP2003167089A (en) * | 2001-11-29 | 2003-06-13 | Toshiba Corp | Nuclear energy facility internal cooling system |
| CN204098971U (en) * | 2014-09-29 | 2015-01-14 | 大唐韩城第二发电有限责任公司 | A kind of Turbine Cold Junction optimization system |
| CN204535449U (en) * | 2015-04-16 | 2015-08-05 | 陕西万方节能科技股份有限公司 | A kind of thermal power plant Air-cooled Unit, water chiller cold junction intermodal system |
-
2018
- 2018-09-25 CN CN201811112696.1A patent/CN109298690B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06185765A (en) * | 1992-12-18 | 1994-07-08 | Toshiba Corp | Cooling facility in power plant |
| JP2002162087A (en) * | 2000-11-22 | 2002-06-07 | Dai-Dan Co Ltd | Variable flow control system for exhaust heat recovery and heat source |
| CN103244433A (en) * | 2013-05-09 | 2013-08-14 | 国家电网公司 | Operation optimizing and monitoring method for variable-frequency circulating water pump of power plant |
| CN106371314A (en) * | 2016-09-29 | 2017-02-01 | 国电科学技术研究院 | Cooling working medium throttling regulation-based load control system and variable working condition calculation method |
| CN107368680A (en) * | 2017-07-14 | 2017-11-21 | 中国华能集团清洁能源技术研究院有限公司 | A kind of steam turbine optimum vacuum real-time computing technique |
| CN107917089A (en) * | 2017-11-17 | 2018-04-17 | 上海交通大学 | Water circulating pump pumps leaf aperture optimal regulation method |
Non-Patent Citations (7)
| Title |
|---|
| 不同判定准则确定循环水系统优化运行的分析;石书雨; 于刚; 张光;《热力发电》;20080915;15-18 * |
| 以电厂循环水为热泵低温热源的联产供热系统的冷端优化;宰相; 张光;《现代电力》;20110210;62-65 * |
| 国产超临界600MW汽轮机冷端优化运行方式的确定;赵伟光; 刘明远; 王丰; 王野;《东北电力技术》;20150620;1-3,23 * |
| 基于改进型综合成本煤耗率的循环水系统优化研究;石书雨;于刚;张光;;《煤矿现代化》;20071215;42-43 * |
| 循环水系统优化运行的经济分析;秦攀; 林闽成; 叶劲松; 孙永平; 董益华;《浙江电力》;20110925;51-60 * |
| 火电厂冷端系统全面数学模型研究及其优化软件开发;李保亮;张光;武东战;;《沈阳工程学院学报(自然科学版)》;20060101;15-18 * |
| 火电机组冷端系统优化运行研究;马帅;《中国优秀硕士学位论文全文数据库》;20101231;34-43 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN109298690A (en) | 2019-02-01 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109298690B (en) | Open type circulating water cooling end system optimization control method | |
| CN101644173B (en) | Method for optimizing steam distribution way of steam turbine | |
| CN107368680A (en) | A kind of steam turbine optimum vacuum real-time computing technique | |
| CN105201564A (en) | Main-steam-flow-based steam turbine sliding pressure optimization control method | |
| CN105787211B (en) | For the Combined Cycle Heat Recovery Boiler pressure method of adjustment of combustion gas turbine deterioration | |
| CN104632302B (en) | A kind of condensing steam turbine sliding pressure operation curve test/implementation methods | |
| CN111577410B (en) | Gas turbine inlet air temperature control device and gas turbine inlet air temperature control method | |
| CN111396301B (en) | Double-frequency-conversion energy-saving control system and method for circulating water pump of seaside power plant | |
| CN111352400B (en) | Heat supply unit sliding pressure operation optimization method and sliding pressure operation control system | |
| CN110566295B (en) | Double-unit coupling peak shaving method and device based on power plant electricity and heat load cooperative scheduling | |
| CN109538317A (en) | A kind of Dynamic calculation method of the heat regenerative system that can be improved peak load regulation ability and heat regenerative system heat storage can vapor (steam) temperature | |
| CN100385092C (en) | Rapid power producing system and method for steam turbine | |
| CN114239218B (en) | Optimization calculation method for main steam pressure of steam turbine set under variable working conditions | |
| CN209978005U (en) | Primary frequency modulation control system for secondary reheating unit | |
| CN106765520B (en) | Automatic control method for realizing optimal initial pressure operation of heat supply unit | |
| CN108131238A (en) | A kind of New PID Control method for inhibiting water hammer pressure fluctuation | |
| CN106932201A (en) | Consider that the fired power generating unit pure condensate operating mode sliding pressure curve of valve throttle loss determines method | |
| CN111507011B (en) | Method for correcting influence quantity of heat supply extraction steam on sliding pressure operation of steam turbine | |
| EP2423459A2 (en) | Method and apparatus for varying flow source to aid in windage heating issue at FSNL | |
| CN114483214B (en) | Condensing and high back pressure switching heat supply system | |
| CN112836419B (en) | Heat source shunting type waste heat power generation system and particle swarm optimization control method thereof | |
| CN112855297B (en) | Heat source shunting type waste heat power generation system and optimization control method thereof | |
| CN114439559B (en) | Heat supply method for switching condensing type and high back pressure of steam turbine generator set | |
| CN214170638U (en) | Gas turbine inlet temperature control device | |
| CN113087055B (en) | Multi-point vacuumizing system and multi-point vacuumizing method of low-temperature multi-effect sea water desalting device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |