阅读说明：本技术 一种凝结水泵深度变频预期效果分析方法 (Method for analyzing expected effect of depth frequency conversion of condensate pump ) 是由 韩立 马汀山 居文平 荆涛 万超 贾明晓 杨珍帅 李高潮 邹洋 李永康 于 2021-09-29 设计创作，主要内容包括：本发明公开了一种凝结水泵深度变频预期效果分析方法,该方法通过大量的运行数据,拟合出来机组负荷和凝结水泵的出口压力、除氧器水位调阀后水压力及除氧器压力的自适应函数曲线,然后计算出不同负荷下的凝结水泵的出口压力、除氧器水位调阀后水压力及除氧器压力值。拟合除氧器上水调门开度超过85％时,机组负荷和凝结水泵的出口压力、除氧器水位调阀后水压力及除氧器压力的自适应函数曲线,预测出此时不同负荷下的凝结水泵出口压力、除氧器水位调阀后水压力及除氧器压力值。比较此时计算出来的不同参数的差值,计算功耗下降值,观察除氧器压力及除氧器水位调阀后水压力的变化量。(The invention discloses a depth frequency conversion expected effect analysis method of a condensate pump, which is characterized in that self-adaptive function curves of unit load, outlet pressure of the condensate pump, water pressure behind a deaerator water level regulating valve and deaerator pressure are fitted through a large amount of operation data, and then the outlet pressure of the condensate pump, the water pressure behind the deaerator water level regulating valve and the deaerator pressure value under different loads are calculated. And fitting the self-adaptive function curves of the unit load, the outlet pressure of the condensate pump, the water pressure behind the water level regulating valve of the deaerator and the deaerator pressure when the opening of the water feeding regulating valve of the deaerator exceeds 85%, and predicting the outlet pressure of the condensate pump, the water pressure behind the water level regulating valve of the deaerator and the deaerator pressure value under different loads at the moment. And comparing the calculated difference values of different parameters, calculating a power consumption reduction value, and observing the pressure of the deaerator and the variable quantity of the water pressure behind the water level regulating valve of the deaerator.)

1. A depth frequency conversion expected effect analysis method of a condensate pump is characterized by comprising the following steps:

step 1, selecting historical data, wherein the historical data comprises unit load, condensate pump outlet pressure, deaerator upper regulating valve opening and deaerator water level regulating valve back water pressure;

step 2, fitting a first function curve representing the relation between the unit load and the outlet pressure of the condensate pump, fitting a second function curve representing the unit load and the deaerator pressure, and fitting a third function curve representing the unit load and the deaerator water pressure after water level adjustment;

step 3, selecting historical data when the opening of an upper regulating valve of the deaerator is larger than 85%, fitting a fourth function curve representing the relation between the unit load and the outlet pressure of the condensate pump, fitting a fifth function curve representing the unit load and the deaerator pressure, and fitting a sixth function curve representing the unit load and the water pressure after the water level of the deaerator is regulated;

step 4, acquiring a difference value of the first function curve and the fourth function curve, wherein the difference value is a change value of outlet pressure of the condensate pump; acquiring a difference value between the second function curve and the fifth function curve, wherein the difference value is a change value of the deaerator pressure; acquiring a difference value between the third function curve and the sixth function curve, wherein the difference value is a change value of the pressure of the deaerator after the water level is adjusted;

when the change value of the pressure of the deaerator is smaller than 0.08MPa and the change value of the pressure of the deaerator after the water level regulating valve is smaller than 0.08, the opening of the water feeding regulating valve of the deaerator is larger than 85% to meet the requirement of the deep frequency conversion effect.

2. The method for analyzing the expected effect of the depth frequency conversion of the condensate pump according to claim 1, wherein in the step 1, the historical data is data between 50% of rated load and 100% of rated load of the unit.

3. The method for analyzing the expected effect of the depth frequency conversion of the condensate pump according to claim 1, wherein in the step 1 and the step 3, historical data are read from a DCS (distributed control System) of the unit.

4. The method for analyzing the expected effect of the depth frequency conversion of the condensate pump according to claim 1, wherein the expression of the first function curve is as follows:

the expression of the fourth function curve is as follows:

wherein, P_NThe outlet pressure value of the condensate pump under the daily operation of the unit is obtained; p_NOThe outlet pressure value of the condensate pump is the value when the opening of the water feeding door is more than 85%; p_eThe load value of the unit under the daily operation of the unit; p_eoThe unit load value is the unit load value when the opening of the water feeding door is more than 85%; a. the₁、A₂、B₁And B₂Are all coefficients; c₁And C₂Are all constants.

5. The method for analyzing the expected effect of the depth frequency conversion of the condensate pump according to claim 1, wherein the expression of the second function curve is as follows:

P_C＝D₁P_e+E₁ (2)

the expression of the fifth function is:

P_CO＝D₂P_eo+E₂ (5)

wherein, P_CIs the pressure value P of a deaerator under the daily operation of a unit_eThe load value of the unit under the daily operation of the unit; p_eoThe unit load value is the unit load value when the opening of the water feeding door is more than 85%; p_COThe pressure value of the deaerator is the pressure value when the opening degree of the water feeding door is more than 85 percent; d₁And D₂Are all coefficients, E₁And E₂Are all constants.

6. The method according to claim 1, wherein the third function is expressed by the following expression:

P_fw＝F₁P_e+G₁ (3)

the expression of the sixth function is:

P_fwo＝F₂P_eo+G₂ (6)

wherein, P_fwRegulating the water pressure behind a valve for the water level of a deaerator in the daily operation of a unit; p_eThe load value of the unit under the daily operation of the unit; p_fwoWhen the opening degree of the water feeding door is more than 85%, the water pressure of the deaerator after the water level is adjusted; p_eoThe unit load value is the unit load value when the opening of the water feeding door is more than 85 percent.

7. The method for analyzing the expected effect of the depth frequency conversion of the condensate pump according to claim 1, wherein after the step 4, a power consumption change rate of the condensate pump and a power consumption reduction value of the condensate pump are calculated.

8. The analysis method for the expected effect of the depth frequency conversion of the condensate pump according to claim 7, wherein the calculation formula of the change rate of the power consumption of the condensate pump is as follows:

the calculation formula of the power consumption reduction value of the condensate pump is as follows:

ΔQ＝Q*δ (11)

the described Δ P_NTo predict condensate pump outlet pressure difference, P_NThe outlet pressure value of the condensate pump under the daily operation of the unit is obtained.

9. The method for analyzing the expected effect of the depth frequency conversion of the condensate pump according to claim 7, wherein the plant power consumption rate of the condensate pump of the unit with the power of more than 600MW grade is reduced to 0.16% -0.18%.

Technical Field

The invention belongs to the field of energy conservation and consumption reduction of coal-fired units, and particularly relates to a depth frequency conversion expected effect analysis method of a condensate pump.

Background

In order to further reduce the power consumption of the condensate pump, the depth frequency conversion of the condensate pump becomes more significant when a part of power plants explores the depth frequency conversion of the condensate pump, especially under the condition that the current unit needs to carry out depth peak regulation. But because some units, condensate pump need provide sealed water for the feed pump, in order to guarantee sealed water's pressure, maintain condensate pump outlet pressure at the high level through adjusting throttle the deaerator upper water, adopt to increase the tubing pump and maintain sealed water pressure the complex degree that can increase the system simultaneously also increased the energy consumption. The current main reason that the deep frequency conversion cannot be realized is that the pressure reduction value of an outlet of a current condensate pump after the opening of a water feeding water regulating valve of a deaerator is increased cannot be estimated.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a depth frequency conversion expected effect analysis method of a condensate pump, so as to solve the problem that the outlet pressure reduction value and further the frequency modulation effect are difficult to predict after the opening of a water feeding and regulating valve of a deaerator is increased in the prior condensate pump.

In order to achieve the purpose, the invention adopts the following technical scheme to realize the purpose:

a depth frequency conversion expected effect analysis method for a condensate pump comprises the following steps:

step 1, selecting historical data, wherein the historical data comprises unit load, condensate pump outlet pressure, deaerator upper regulating valve opening and deaerator water level regulating valve back water pressure;

step 2, fitting a first function curve representing the relation between the unit load and the outlet pressure of the condensate pump, fitting a second function curve representing the unit load and the deaerator pressure, and fitting a third function curve representing the unit load and the deaerator water pressure after water level adjustment;

step 3, selecting historical data when the opening of an upper regulating valve of the deaerator is larger than 85%, fitting a fourth function curve representing the relation between the unit load and the outlet pressure of the condensate pump, fitting a fifth function curve representing the unit load and the deaerator pressure, and fitting a sixth function curve representing the unit load and the water pressure after the water level of the deaerator is regulated;

step 4, acquiring a difference value of the first function curve and the fourth function curve, wherein the difference value is a change value of outlet pressure of the condensate pump; acquiring a difference value between the second function curve and the fifth function curve, wherein the difference value is a change value of the deaerator pressure; acquiring a difference value between the third function curve and the sixth function curve, wherein the difference value is a change value of the pressure of the deaerator after the water level is adjusted;

when the change value of the pressure of the deaerator is smaller than 0.08MPa and the change value of the pressure of the deaerator after the water level regulating valve is smaller than 0.08, the opening of the water feeding regulating valve of the deaerator is larger than 85% to meet the requirement of the deep frequency conversion effect.

The invention is further improved in that:

preferably, in step 1, the historical data is data between 50% of rated load and 100% of rated load of the unit.

Preferably, in step 1 and step 3, the historical data is read from the DCS system of the plant.

Preferably, the expression of the first function curve is:

P_N＝A₁P_e ²-B₁P_e+C₁ (1)

the expression of the fourth function curve is as follows:

wherein, P_NThe outlet pressure value of the condensate pump under the daily operation of the unit is obtained; p_NOThe outlet pressure value of the condensate pump is the value when the opening of the water feeding door is more than 85%; p_eThe load value of the unit under the daily operation of the unit; p_eoThe unit load value is the unit load value when the opening of the water feeding door is more than 85%; a. the₁、A₂、B₁And B₂Are all coefficients; c₁And C₂Are all constants.

Preferably, the expression of the second function curve is:

P_C＝D₁P_e+E₁ (2)

the expression of the fifth function is:

P_CO＝D₂P_eo+E₂ (5)

wherein, P_CIs the pressure value P of a deaerator under the daily operation of a unit_eThe load value of the unit under the daily operation of the unit; p_eoThe unit load value is the unit load value when the opening of the water feeding door is more than 85%; p_COThe pressure value of the deaerator is the pressure value when the opening degree of the water feeding door is more than 85 percent; d₁And D₂Are all coefficients, E₁And E₂Are all constants.

Preferably, the expression of the third function is:

P_fw＝F₁P_e+G₁ (3)

the expression of the sixth function is:

P_fwo＝F₂P_eo+G₂ (6)

wherein, P_fwRegulating the water pressure behind a valve for the water level of a deaerator in the daily operation of a unit; p_eThe load value of the unit under the daily operation of the unit; p_fwoWhen the opening degree of the water feeding door is more than 85%, the water pressure of the deaerator after the water level is adjusted; p_eoThe unit load value is the unit load value when the opening of the water feeding door is more than 85 percent.

Preferably, after the step 4, the power consumption change rate of the condensate pump and the power consumption reduction value of the condensate pump are calculated.

Preferably, the calculation formula of the power consumption change rate of the condensate pump is as follows:

the calculation formula of the power consumption reduction value of the condensate pump is as follows:

ΔQ＝Q*δ (11)

the described Δ P_NTo predict condensate pump outlet pressure difference, P_NThe outlet pressure value of the condensate pump under the daily operation of the unit is obtained.

Preferably, the service power consumption of the condensate pump of the unit with the power of more than 600MW grade is reduced to 0.16-0.18%.

Compared with the prior art, the invention has the following beneficial effects:

the invention discloses a depth frequency conversion expected effect analysis method of a condensate pump, which is characterized in that self-adaptive function curves of unit load, outlet pressure of the condensate pump, water pressure behind a deaerator water level regulating valve and deaerator pressure are fitted through a large amount of operation data, and then the outlet pressure of the condensate pump, the water pressure behind the deaerator water level regulating valve and the deaerator pressure value under different loads are calculated. And fitting the self-adaptive function curves of the unit load, the outlet pressure of the condensate pump, the water pressure behind the water level regulating valve of the deaerator and the deaerator pressure when the opening of the water feeding regulating valve of the deaerator exceeds 85%, and predicting the outlet pressure of the condensate pump, the water pressure behind the water level regulating valve of the deaerator and the deaerator pressure value under different loads at the moment. And comparing the calculated difference values of different parameters, calculating a power consumption reduction value, and observing the pressure of the deaerator and the variable quantity of the water pressure behind the water level regulating valve of the deaerator. Through comparison, after the opening degree is increased, the power consumption is obviously reduced, other parameters are not changed greatly, and the condition that the pressure of the sealing water of the pump is insufficient is avoided. After the opening of the water feeding regulating valve of the deaerator is increased, the throttling of the water feeding regulating valve of the deaerator is reduced, and the large power consumption of the condensate pump is reduced.

Drawings

FIG. 1 is a block diagram of a condensate pump deep conversion system according to the present invention;

FIG. 2 is a diagram showing the relationship between parameters such as outlet pressure of a condensate pump and unit load during daily operation;

FIG. 3 is a diagram showing the relationship between water pressure and unit load after the deaerator water level is adjusted to a valve in daily operation;

FIG. 4 is a diagram showing the relationship between parameters such as outlet pressure of a condensate pump and unit load when the opening of a water gate is greater than 85%;

FIG. 5 is a diagram showing the relationship between water pressure and unit load after the deaerator water level is adjusted when the opening of the water feeding door is larger than 85%;

wherein: 1-a steam turbine; 2-a condenser; 3-deaerator pressure; 4-a deaerator; 5-a low-pressure heater; 6-water pressure after the water level of the deaerator is adjusted; 7-a water feeding regulating valve of the deaerator; 8-condensate pump motor current; 9-condensate pump speed; 10-condensate pump outlet pressure; 11-a condensate pump; 12-condensate pump motor frequency converter.

Detailed Description

The invention is described in further detail below with reference to the accompanying drawings:

the invention discloses a depth frequency conversion expected effect analysis method of a condensate pump, and a system for the method comprises a steam turbine 1, a condensate pump 11, a condenser 2, a deaerator 4, a deaerator water feeding regulating valve 7 and the like as shown in figure 1. The exhaust steam output end of the steam turbine 1 is communicated with the condenser 2, the condensed water output end of the condenser 2 is communicated with the condensed water pump 11, the output end of the condensed water pump 11 is connected with the low-pressure heater 5, and the output end of the low-pressure heater 5 is connected with the deaerator 4. The condensate pump 11 is connected to a condensate pump motor frequency converter 12 for adjusting the operating frequency of the condensate pump 11. A deaerator water-feeding regulating valve 7 is arranged between the condensate pump 11 and the low-pressure heater 5, a third pressure gauge 10 and a condensate pump revolution meter 9 are sequentially arranged between the condensate pump 11 and the deaerator water-feeding regulating valve 7, the third pressure gauge 10 is used for measuring the outlet pressure of the condensate pump 11, and meanwhile deaerator water is the water pressure before a regulating valve. Be provided with motor ammeter 8 on the motor of drive condensate pump 11, motor ammeter 8 measures the current value of drive condensate pump 11, is provided with second manometer 6 between oxygen-eliminating device sail governing valve 7 and the low pressure feed water heater 5, and second manometer 6 is used for measuring oxygen-eliminating device water level governing valve back water pressure. The deaerator 4 is connected with a first pressure gauge for measuring the pressure of the deaerator 4.

The outlet pressure value of the deaerator 4 after the opening of the water feeding regulating valve is increased can be analyzed through an accurate prediction method to meet the pressure requirement of sealing water for the pump, and an operator can gradually increase the opening of the water feeding regulating valve of the deaerator through a valve regulating test to reduce the running rotating speed of the condensed water pump.

The method for analyzing the expected effect of the depth frequency conversion of the condensate pump based on the device comprises the following steps:

step 1, selecting historical data from a DCS, wherein the historical data comprises unit load, condensate pump outlet pressure, deaerator upper regulating valve opening and deaerator water level regulating valve back water pressure; the historical data is data between 50% of rated load and 100% of rated load of the unit.

Step 2, fitting a first function curve representing the relation between the unit load and the outlet pressure of the condensate pump according to data between 50% of rated load and 100% of rated load, fitting a second function curve representing the unit load and the deaerator pressure, and fitting a third function curve representing the unit load and the deaerator water pressure after water level adjustment;

the expression of the first function curve is:

P_N＝A₁P_e ²-B₁P_e+C₁ (1)

the expression of the second function curve is:

P_C＝D₁P_e+E₁ (2)

the expression of the third function is:

P_fw＝F₁P_e+G₁ (3)

wherein, P_NThe outlet pressure value P of the condensate pump under the daily operation of the unit_CIs the pressure value P of a deaerator under the daily operation of a unit_eIs a unit load value P under the daily operation of the unit_fwRegulating the water pressure behind a valve for the water level of a deaerator in the daily operation of a unit; a. the₁、B₁、D₁、F₁Are all coefficients; c₁、E₁And G₁Are all constants.

Step 3, selecting historical data when the opening of an upper regulating valve of the deaerator is larger than 85%, fitting a fourth function curve representing the relation between the unit load and the outlet pressure of the condensate pump, fitting a fifth function curve representing the unit load and the deaerator pressure, and fitting a sixth function curve representing the unit load and the water pressure after the water level of the deaerator is regulated;

the expression of the fourth function curve is:

the expression of the fifth function is:

P_CO＝D₂P_eo+E₂ (5)

the expression of the sixth function is:

P_fwo＝F₂P_eo+G₂ (6)

P_NOthe outlet pressure value P of the condensate pump when the opening of the water feeding door is more than 85 percent_eoThe unit load value is the unit load value when the opening of the water feeding door is more than 85%; p_NOThe outlet pressure value of the condensate pump is the value when the opening of the water feeding door is more than 85%; p_eThe load value of the unit under the daily operation of the unit; p_eoThe opening degree of the water feeding door is larger thanA unit load value at 85%; p_fwoWhen the opening degree of the water feeding door is more than 85%, the water pressure of the deaerator after the water level is adjusted; a. the₂、B₂、D₂、F₂Are all coefficients; c₂、E₂And G₂Are all constants.

Step 4, acquiring a difference value of the first function curve and the fourth function curve, wherein the difference value is a change value of outlet pressure of the condensate pump; acquiring a difference value between the second function curve and the fifth function curve, wherein the difference value is a change value of the deaerator pressure; acquiring a difference value between the third function curve and the sixth function curve, wherein the difference value is a change value of the pressure of the deaerator after the water level is adjusted;

the difference between the first function curve and the fourth function curve is:

ΔP_C＝D₂P_eo+E₂-D₁P_e-E₁ (8)

ΔP_fw＝F₂P_eo+G₂-F₁P_e-G₁ (9)

when the change value of the pressure of the deaerator is smaller than 0.08MPa and the change value of the pressure of the deaerator after the water level regulating valve is smaller than 0.08MPa, the fact that the opening of the water feeding regulating valve of the deaerator is larger than 85% meets the requirement of the deep frequency conversion effect is shown, and basically no influence is caused on rear-end equipment needing the condensate pump to provide the pressure. And the power consumption of the feed water pump is increased basically negligibly in the pressure variation range. Meanwhile, the opening of the water feeding regulating valve of the deaerator is increased, the pressure value of the outlet of the condensate pump 11 is reduced, and the throttling loss of the outlet of the condensate pump 11 is effectively reduced.

The change rate and change value of the power consumption value of the condensate pump caused by the pressure reduction at the outlet of the condensate pump are as follows

ΔQ＝Q*δ (11)

Note: delta-rate of change of power consumption value of condensate pump;

delta Q-power consumption change value of condensate pump;

q- -the current power consumption value of the condensate pump, and Q is obtained by calculating the current value measured by the motor ammeter 8.

Examples

Firstly, historical data of unit load, condensate pump outlet pressure, deaerator water feeding regulating opening and deaerator water level regulating valve back water pressure are taken out from a unit DCS system, data points are guaranteed to exist from 50% THA to 100% THA load, and then adaptive function curves of the unit load, the condensate pump outlet pressure, deaerator water level regulating valve back water pressure and deaerator pressure are fitted out, and the adaptive function curves are shown in fig. 2 and fig. 3.

P_N＝0.00000274P_e ²-0.00264838P_e+2.32217 (12)

P_C＝0.001P_e+0.0738 (13)

P_fw＝0.0017P_e+0.1867 (14)

Note: p_N- -condensate pump outlet pressure value under daily operation of the unit

P_e- -unit load value under daily operation of the unit

P_C- -deaerator pressure value under daily operation of unit

P_fw- - -deaerator water level post-valve regulation water pressure under daily operation of unit

The self-adaptive function curves of the unit load, the condensate pump outlet pressure, the deaerator water level regulating valve back water pressure and the deaerator pressure are obtained by combining the fig. 2 and fig. 3 with the deaerator water-feeding regulating valve characteristic analysis, and when the fitted deaerator water-feeding regulating valve opening exceeds 85% (when the regulating valve opening is greater than 85%, the throttling loss becomes very small). Fig. 4 and 5 result.

P_CO＝0.0009P_eo+0.1309 (16)

P_fwo＝0.0017P_eo+0.2323 (17)

Note: p_NO-outlet pressure value of condensate pump when opening of water supply gate is greater than 85%

P_eo-when the opening of the water supply gate is greater than 85%, the load value of the unit

P_CO-when the opening of the water feeding door is more than 85%, the pressure value of the deaerator

P_fwo-when the opening of the water feeding door is more than 85%, the water pressure behind the water level regulating valve of the deaerator

By making a difference of the relational expression of the previous and subsequent steps, when the opening of the water feeding regulating valve of the deaerator is more than 85% above 50% THA load, the outlet pressure of the condensate pump, the pressure of the deaerator and the water pressure change value behind the water level regulating valve of the deaerator are as follows:

ΔP_C＝0.0009P_eo-0.001P_e+0.0571 (19)

ΔP_fw＝0.0017P_eo-0.0017P_e+0.0456 (20)

note: delta P_NPredicting condensate pump outlet pressure differential

ΔP_CPredicting the deaerator pressure differential

ΔP_fw-predicting the water pressure behind the deaerator water level regulating valve

Taking a 1000MW unit as an example, the load values of the unit before and after prediction are the same, and under a representative load, the difference value of the current value of the predicted value can be obtained, and the result is as follows:

TABLE 1 Difference

It can be seen from the above table that by reducing the throttling of the water-feeding regulating valve of the deaerator, the pressure drop of the outlet of the condensate pump under low load is obvious, and meanwhile, after the opening of the regulating valve is increased, the pressure drop of the deaerator is not obvious, and the water pressure change value after the water level regulating valve of the deaerator is increased to a certain extent, so that the pressure of the sealing water of the pump cannot be influenced. By reducing the condensate pump outlet pressure, a reduced value of the condensate pump power consumption can be calculated.

The change rate and change value of the power consumption value of the condensate pump caused by the pressure reduction at the outlet of the condensate pump are as follows

ΔQ＝Q*δ (22)

Note: delta-rate of change of power consumption value of condensate pump;

delta Q-power consumption change value of condensate pump;

q-current power consumption value of condensate pump

Taking a 1000MW unit as an example, the power consumption reduction value can be obtained under a representative load, and the result is as follows:

TABLE 2 Power consumption reduction Table

As can be seen from the table, below 750MW, the unit power is obviously reduced, the flow cannot be greatly reduced, and the normal operation of the unit cannot be influenced.

The annual energy consumption reduction can be calculated by counting the unit load rate, the unit operation hours of every 10% THA load section can be counted in a detailed mode, and then the annual condensed water pump electricity saving rate of the unit is calculated according to the reduction values of the condensed water pump power consumption under different loads.

Effect of putting into operation

After the opening of the water feeding throttle of the deaerator is increased, the throttle of the water feeding throttle of the deaerator is reduced, the large power consumption of a condensate pump is reduced, the plant power consumption rate of the condensate pump of a unit with the power grade of more than 600MW is about 0.2% before frequency conversion, and the predicted energy after frequency conversion can be reduced to 0.16% -0.18%.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.