Heat supply temperature adjusting method for reducing condensate pump power consumption and heat supply device

Abstract

The invention relates to a heat supply temperature adjusting method for reducing condensate pump power consumption and a heat supply device.The method comprises the steps that the unit load state, the heat supply steam outlet temperature, the heat supply steam pipeline pressure and the condensate water pressure are obtained in real time, and the desuperheating water flow needed by a unit and the control valve opening degree of a heat supply desuperheating water adjusting valve are calculated; when the condensed water pressure is larger than the heat supply steam pipeline pressure or the control valve opening degree is smaller than the opening degree threshold value, the booster water pump set is stopped, the control valve opening degree of a heat supply desuperheating water adjusting valve and the frequency of a condensed water pump are adjusted, and the heat supply steam outlet temperature is stabilized within the specified temperature interval; otherwise, starting the booster pump, reducing the frequency of the condensate pump to the lowest economic rotating speed, and adjusting the frequency of the booster pump and the control valve opening degree of the heat supply desuperheating water adjusting valve. Compared with the prior art, the overall power consumption is remarkably reduced, and the contradiction that a traditional single-pump system is difficult to consider economic, efficiency and pressure requirements within a wide load range is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of power generation equipment, and in particular to a heating temperature regulating method and a heating device for reducing the power consumption of a condensing pump. Background Art

[0002] In a thermal power plant, various pumps and fans account for approximately 85% of the plant's own electricity consumption. The condensate pump is a key auxiliary equipment in the steam turbine thermal system. Its function is not only to pump condensate from the condenser into the low-pressure heater for heating and then to feed it into the deaerator, but also to pump condensate into the heating steam pipeline to cool it. Excessively high steam temperatures can damage equipment components that come into contact with the steam. Heating steam temperature must be strictly controlled within the range of 320°C-345°C. Without or inappropriate cooling, the outlet temperature of the heating steam can easily become excessively high. A stable heating temperature prevents damage to the heating pipelines caused by excessive temperature fluctuations, extending their service life and ensuring that the heating quality meets user requirements.

[0003] In current thermal power plant heating systems, condensate pumps face several pressing challenges. First, they consume high amounts of electricity. When cooling steam using condensate, under high-load conditions, when the heating desuperheating water regulating valve reaches 100% opening, the condensate pump frequency must be increased to lower the steam temperature. This results in a reduction in the main regulating valve opening, increasing throttling losses, and, in turn, increasing condensate pump power consumption, plant power utilization, and operating costs. Second, heating temperatures are unstable. Due to untimely desuperheating water adjustments, the heating steam outlet temperature can easily become excessively high. While heating temperatures must be strictly controlled between 320°C and 345°C, large temperature fluctuations can shorten the service life of heating pipes and impact the safety and stability of equipment.

[0004] Chinese patent application CN118517424A discloses a variable frequency automatic control method for a condensate pump to save energy and reduce consumption. This method, based on a condensate desuperheating system, includes a condensate pump, a deaerator, and a turbine exhaust. The method includes: selecting the turbine exhaust as the steam source, desuperheating the initial gas output by the steam source with condensate water, and then outputting cooled heating gas; obtaining the temperature of the cooled heating gas, adjusting the opening of the deaerator's water level regulator main valve based on the temperature, and simultaneously obtaining the pressure of the cooled heating gas to perform frequency modulation control on the condensate pump. The frequency modulation control target is to ensure that the pressure of the condensate main pipe is equal to the sum of the heating gas pressure and the pressure offset. However, this patent relies solely on a single condensate pump for pressure regulation and fails to consider the differences in pressure requirements under high and low load conditions. Insufficient condensate pressure under high load conditions may require the condensate pump to operate continuously at high frequency, resulting in high power consumption.

[0005] Therefore, an improved heating and cooling water control method is urgently needed to solve the above problems. Summary of the Invention

[0006] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and provide a heating temperature regulation method and a heating device that reduce the power consumption of the condensing pump.

[0007] The purpose of the present invention can be achieved by the following technical solutions:

[0008] A heating temperature regulation method for reducing power consumption of a condensing pump, the method comprising:

[0009] Obtain the unit load status, heating steam outlet temperature, heating steam pipeline pressure and condensate pressure in real time, and calculate the required desuperheating water flow rate and the throttle opening of the heating desuperheating water regulating valve;

[0010] When the condensate pressure is greater than the heating steam pipeline pressure or the regulating valve opening is less than the opening threshold, the booster water pump group is stopped, and the PID algorithm is used to adjust the regulating valve opening of the heating and desuperheating water regulating valve, and the condensate pump frequency is adjusted according to the water pump head-flow characteristics to stabilize the heating steam outlet temperature within the specified temperature range; otherwise, the booster pump is activated, the condensate pump frequency is reduced to the lowest economic speed, and the booster pump outlet pressure is used as a reference to recalculate the regulating valve opening of the heating and desuperheating water regulating valve, and the booster pump frequency is adjusted according to the water pump head-flow characteristics, and the PID algorithm is used to adjust the regulating valve opening of the heating and desuperheating water regulating valve to stabilize the heating steam outlet temperature within the specified temperature range;

[0011] There are at least two booster pumps, and when the outlet pressure difference between the booster pumps is greater than a threshold, an alarm is triggered.

[0012] Furthermore, the calculation expression for the desuperheating water flow rate required by the unit is:

[0013]

[0014] Among them, m 蒸汽 is the heating steam flow rate, h1 is the enthalpy of the heating steam before desuperheating, h2 is the target enthalpy of the heating steam, c is the specific heat capacity of water, t2 is the target steam temperature, and t1 is the condensate temperature.

[0015] Furthermore, the calculation expression of the regulating valve opening of the heating and desuperheating water regulating valve is:

[0016]

[0017] Among them, μ is the regulating valve opening of the heating and cooling water regulating valve, m 减温水 is the desuperheating water flow required by the unit, K is the flow coefficient of the valve, A is the flow cross-sectional area when the valve is fully open, ΔP is the pressure difference between the condensate and the heating steam, and ρ is the condensate density.

[0018] Furthermore, according to the pump head-flow characteristics, the adjustment expression of the condensate pump frequency is:

[0019]

[0020] Among them, f0 is the rated frequency of the condensate pump, H i is the target head of the condensate pump, H imax is the rated head of the condensate pump, S is the pipeline resistance coefficient, Q 2 is the condensate flow rate, H i0 is the theoretical condensate pump head, ρ is the condensate density, P i is the target condensate pump outlet pressure, and g is the acceleration due to gravity.

[0021] Furthermore, the PID algorithm expression for adjusting the valve opening of the heating and cooling water regulating valve is:

[0022]

[0023] Among them, μ0 is the initial opening of the heating and cooling water regulating valve, e(t) is the temperature deviation at time t, K p is the proportional coefficient, T i is the integration time, T d is the differential time;

[0024] e(t)=T 实测 -332.5

[0025] Among them, T 实测 The outlet temperature of the heating steam is measured in real time.

[0026] Furthermore, according to the pump head-flow characteristics, the adjustment expression of the booster pump frequency is:

[0027]

[0028] Among them, f0 is the rated frequency of the booster pump, H j is the target head of the booster pump, H jmax is the rated head of the booster pump, S is the pipeline resistance coefficient, Q 2 is the condensate flow rate, H j0 is the theoretical booster pump head, ρ is the condensate density, P j is the target booster pump outlet pressure, P i is the outlet pressure of the condensate pump at the lowest economic speed, and g is the acceleration due to gravity.

[0029] Furthermore, the minimum economic speed is a speed at which the flow rate of the condensate pump is greater than 30% of the rated flow rate of the condensate pump.

[0030] Furthermore, when the valve opening is 100% and the heating steam outlet temperature is still higher than 345°C, an alarm is triggered and the booster water pump group is forced to start, and the booster water pump group is used to adjust the heating temperature.

[0031] Furthermore, when the regulating valve opening is lower than 5% and the outlet temperature of the heating steam is lower than 320°C, the heating and cooling water regulating valve is closed.

[0032] A heating device based on the heating temperature regulation method for reducing the power consumption of a condensing pump as described in any one of the above items, the device comprising:

[0033] Heating system: generates heating steam and outputs heating steam through heating steam pipelines;

[0034] Condensate system: provides condensate for cooling;

[0035] Heating steam pipeline: outputs heating steam to the outside;

[0036] Desuperheating water boosting module: Based on the data collected by the monitoring module, the condensate pump and booster water pump are dynamically adjusted to pump condensate to the heating steam pipeline to cool the heating steam pipeline;

[0037] Monitoring module: obtains unit load status, heating steam outlet temperature, heating steam pipeline pressure and condensate pressure.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] 1. This invention achieves precise matching of high and low load conditions through dynamic switching between the condensate pump and the booster pump. During high load conditions, the booster pump is disabled and directly regulated by the condensate pump. During low load conditions, the booster pump is enabled and the condensate pump frequency is reduced to prevent it from operating in an inefficient range. This phased control strategy significantly reduces overall power consumption and resolves the difficulty of traditional single-pump systems in balancing efficiency and pressure requirements across a wide load range.

[0040] 2. The present invention comprehensively considers multiple parameters such as unit load, steam temperature, pressure, and valve opening, and constructs a complete closed-loop control system, which can achieve precise control of temperature.

[0041] 3. The present invention sets multiple safety thresholds. These mechanisms ensure that the system can still operate stably under extreme working conditions, prevent equipment damage and heating accidents, and improve the safety of the heating system.

[0042] 4. This invention is applicable to all types of cogeneration units, especially peak-shaving units with large load fluctuations. The system only requires the addition of a booster pump and control system to the existing condensate system, resulting in low modification costs and high promotion value. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 Flow chart of the method of the present invention;

[0044] Figure 2 Schematic diagram of the heating device of the present invention. DETAILED DESCRIPTION

[0045] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0046] Example 1

[0047] This embodiment discloses a method for regulating the heating temperature to reduce the power consumption of the condensing pump. Figure 1 Shown, including:

[0048] Step S1, real-time acquisition of unit load status, heating steam outlet temperature, heating steam pipeline pressure, and condensate pressure;

[0049] Step S2, calculating the required desuperheating water flow rate and the throttle opening of the heating desuperheating water regulating valve of the computer group;

[0050] Step S3, when the condensate pressure is greater than the heating steam pipeline pressure or the valve opening is less than the opening threshold, the booster pump group is stopped, and the PID algorithm is used to adjust the valve opening of the heating and desuperheating water regulating valve, and the condensate pump frequency is adjusted according to the water pump head-flow characteristics, so that the condensate pump can stabilize the heating steam outlet temperature within the specified temperature range; otherwise, the booster pump is enabled, the condensate pump frequency is reduced to the lowest economic speed, and the booster pump outlet pressure is used as a reference to recalculate the valve opening of the heating and desuperheating water regulating valve, and the booster pump frequency is adjusted according to the water pump head-flow characteristics, and the PID algorithm is used to adjust the valve opening of the heating and desuperheating water regulating valve.

[0051] The condensate pump must meet the dual flow requirements of deaerator water supply and heating and desuperheating water at the same time, and its design head must cover the maximum pressure of both (such as deaerator pressure + heating steam pressure + pipeline resistance).

[0052] In this embodiment, there are at least two booster pumps, and an alarm is triggered when the outlet pressure difference between the booster pumps is greater than a threshold.

[0053] When the valve opening is 100% and the heating steam outlet temperature is still higher than 345°C, the alarm is triggered and the booster water pump group is forced to start, and the booster water pump group is used to adjust the heating temperature.

[0054] When the regulating valve opening is lower than 5% and the heating steam outlet temperature is lower than 320℃, close the heating and cooling water regulating valve.

[0055] In another embodiment, there are at least two booster pumps, one for boosting and the other as a backup booster pump to replace the other booster pump when it is damaged.

[0056] In this embodiment, the heating system using the heating temperature adjustment method for reducing the power consumption of the condensing pump is as follows: Figure 2 shown.

[0057] Figure 2 The power generation section consists of two 650MW coal-fired steam turbine generator sets, each with an ultra-high-pressure (UHP) and high-pressure (HP) cylinder. The heating section uses a shared steam cylinder, with primary reheat steam for low loads and secondary reheat steam for high loads, depending on the load. Two heating desuperheating water booster pumps (one for operation and one for backup) and a condensate pump are also provided, along with various valves, piping, and other components.

[0058] Steam flow direction:

[0059] Main steam: The main steam enters the ultra-high pressure cylinder. Part of the exhaust steam from the ultra-high pressure cylinder can flow to the heating system through related pipelines, and the other part enters the subsequent process (such as to No. 1 high pressure heater, etc.).

[0060] Primary reheat steam: Primary high-temperature reheat steam A and B enter the high-pressure cylinder. Part of the exhaust steam from the high-pressure cylinder can enter the heating system, and the other part goes to the secondary reheat system (such as to the shaft steam header, No. 3 high-pressure heater, feed water pump turbine, etc.).

[0061] Desuperheating water flow direction:

[0062] Condensate: Condensate is used as a source of cooling water and can be connected to the heating cooling water booster pumps A and B (the two are connected in parallel) through pipes.

[0063] Booster Pump: After passing through the booster pump, the desuperheated water is piped to the heating system to regulate the heating steam temperature. During high loads, when condensate pressure is sufficient, the temperature can be adjusted directly by regulating the desuperheated water flow rate through the condensate pump, with the booster pump deactivated. During low loads or when the heating flow rate decreases, and specific valve opening conditions are met, the condensate pump can also be adjusted to control the temperature, with the booster pump deactivated.

[0064] The system also has connecting pipes such as those to the condenser ventilation pipes, various heaters (such as No. 1 high-pressure heater and No. 3 high-pressure heater), feed water pump turbine, etc., which are used to transmit media such as steam and water to achieve coordinated operation of the entire power generation and heating system.

[0065] In step S2, the calculation expression for the desuperheating water flow rate required by the unit is:

[0066]

[0067] Among them, m 蒸汽 is the heating steam flow rate, h1 is the enthalpy of the heating steam before desuperheating, h2 is the target enthalpy of the heating steam, c is the specific heat capacity of water, t2 is the target steam temperature, and t1 is the condensate temperature.

[0068] The value of t2 is between 320° and 345°, which is the standard temperature for heating steam.

[0069] The calculation expression of the regulating valve opening of the heating and cooling water regulating valve is:

[0070]

[0071] Among them, μ is the regulating valve opening of the heating and cooling water regulating valve, m 减温水 is the desuperheating water flow required by the unit, K is the flow coefficient of the valve, A is the flow cross-sectional area when the valve is fully open, ΔP is the pressure difference between the condensate and the heating steam, and ρ is the condensate density.

[0072] The principle expression of the pump head-flow characteristic mentioned in step S3 is:

[0073] H=H0-S·Q 2

[0074] Among them, H is the pump head, H0 is the theoretical pump head, S is the pipeline resistance coefficient, Q 2 is the condensate flow rate;

[0075]

[0076] Where ρ is the density of condensate, P is the pump outlet pressure, and g is the acceleration due to gravity.

[0077] In step S3, according to the pump head-flow characteristics, the adjustment expression of the condensate pump frequency in the logging reservoir evaluation method based on variational mode decomposition and geological prior constraints is:

[0078]

[0079] Among them, f0 is the rated frequency of the condensate pump, H i is the target head of the condensate pump, H imax is the rated head of the condensate pump, S is the pipeline resistance coefficient, Q 2 is the condensate flow rate, H i0 is the theoretical condensate pump head, ρ is the condensate density, P i is the target condensate pump outlet pressure, and g is the acceleration due to gravity.

[0080] The PID algorithm expression for adjusting the valve opening of the heating and cooling water regulating valve is:

[0081]

[0082] Among them, μ0 is the initial opening of the heating and cooling water regulating valve, e(t) is the temperature deviation at time t, K p is the proportional coefficient, T i is the integration time, T d is the differential time;

[0083] e(t)=T 实测 -332.5

[0084] Among them, T 实测 The outlet temperature of the heating steam is measured in real time.

[0085] The value of 332.5° here is the middle value within the range of 320℃-345℃, ensuring that the temperature is in a safe range.

[0086] According to the pump head-flow characteristics, the adjustment expression of the booster pump frequency is:

[0087]

[0088] Among them, f0 is the rated frequency of the booster pump, H j is the target head of the booster pump, H jmax is the rated head of the booster pump, S is the pipeline resistance coefficient, Q 2 is the condensate flow rate, H j0 is the theoretical booster pump head, ρ is the condensate density, P j is the target booster pump outlet pressure, P i is the outlet pressure of the condensate pump at the lowest economic speed, and g is the acceleration due to gravity.

[0089] In step S3, the lowest economic speed is a speed at which the flow rate of the condensate pump is greater than 30% of the rated flow rate of the condensate pump. Maintaining the lowest economic speed can avoid cavitation.

[0090] After installing the booster pump, the frequency of the condensate pump can be reduced to 30Hz at low load, the speed is reduced → the impeller wear is reduced → the life is extended.

[0091] Example 2

[0092] This embodiment discloses a heating device based on the heating temperature adjustment method for reducing the power consumption of the condensing pump in Example 1, comprising:

[0093] Heating system: generates heating steam and outputs heating steam through heating steam pipelines;

[0094] Condensate system: provides condensate for cooling;

[0095] Heating steam pipeline: outputs heating steam to the outside;

[0096] Desuperheating water boosting module: Based on the data collected by the monitoring module, the condensate pump and booster water pump are dynamically adjusted to pump condensate to the heating steam pipeline to cool the heating steam pipeline;

[0097] Monitoring module: obtains unit load status, heating steam outlet temperature, heating steam pipeline pressure and condensate pressure.

[0098] The specific details of the above modules and systems can be understood by referring to the relevant descriptions and effects in Example 1.

[0099] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and such modifications or substitutions are intended to be within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be subject to the scope of protection of the claims.

Claims

1. A heating temperature regulation method for reducing the power consumption of a condensing pump, characterized in that: The method comprises: Obtain the unit load status, heating steam outlet temperature, heating steam pipeline pressure and condensate pressure in real time, and calculate the required desuperheating water flow rate and the throttle opening of the heating desuperheating water regulating valve; When the condensate pressure is greater than the heating steam pipeline pressure or the regulating valve opening is less than the opening threshold, the booster water pump group is stopped, and the PID algorithm is used to adjust the regulating valve opening of the heating and desuperheating water regulating valve, and the condensate pump frequency is adjusted according to the water pump head-flow characteristics to stabilize the heating steam outlet temperature within the specified temperature range; otherwise, the booster pump is activated, the condensate pump frequency is reduced to the lowest economic speed, and the booster pump outlet pressure is used as a reference to recalculate the regulating valve opening of the heating and desuperheating water regulating valve, and the booster pump frequency is adjusted according to the water pump head-flow characteristics, and the PID algorithm is used to adjust the regulating valve opening of the heating and desuperheating water regulating valve to stabilize the heating steam outlet temperature within the specified temperature range; There are at least two booster pumps, and when the outlet pressure difference between the booster pumps is greater than a threshold, an alarm is triggered.

2. A heating temperature regulation method for reducing the power consumption of a condensing pump according to claim 1, characterized in that: The calculation expression of the desuperheating water flow required by the unit is: Among them, m 蒸汽 is the heating steam flow rate, h1 is the enthalpy of the heating steam before desuperheating, h2 is the target enthalpy of the heating steam, c is the specific heat capacity of water, t2 is the target steam temperature, and t1 is the condensate temperature.

3. A heating temperature regulation method for reducing power consumption of a condensate pump according to claim 1, characterized in that: The calculation expression of the regulating valve opening of the heating and desuperheating water regulating valve is: Among them, μ is the opening of the heating and cooling water regulating valve, m 减温水 is the desuperheating water flow required by the unit, K is the flow coefficient of the valve, A is the flow cross-sectional area when the valve is fully open, ΔP is the pressure difference between the condensate and the heating steam, and ρ is the condensate density.

4. A heating temperature regulation method for reducing power consumption of a condensate pump according to claim 1, characterized in that: According to the pump head-flow characteristics, the adjustment expression of the condensate pump frequency is: Among them, f0 is the rated frequency of the condensate pump, H i is the target head of the condensate pump, H imax is the rated head of the condensate pump, S is the pipeline resistance coefficient, Q 2 is the condensate flow rate, H i0 is the theoretical condensate pump head, ρ is the condensate density, P i is the target condensate pump outlet pressure, and g is the acceleration due to gravity.

5. A heating temperature regulation method for reducing power consumption of a condensate pump according to claim 1, characterized in that: The PID algorithm expression for adjusting the valve opening of the heating and desuperheating water regulating valve is: Among them, μ0 is the initial opening of the heating and cooling water regulating valve, e(t) is the temperature deviation at time t, K p is the proportional coefficient, T i is the integration time, T d is the differential time; e(t)=T 实测 -332.5 Among them, T 实测 The outlet temperature of the heating steam is measured in real time.

6. A heating temperature regulation method for reducing power consumption of a condensate pump according to claim 1, characterized in that: According to the pump head-flow characteristics, the adjustment expression of the booster pump frequency is: Among them, f0 is the rated frequency of the booster pump, H j is the target head of the booster pump, H jmax is the rated head of the booster pump, S is the pipeline resistance coefficient, Q 2 is the condensate flow rate, H j0 is the theoretical booster pump head, ρ is the condensate density, P j is the target booster pump outlet pressure, P i is the outlet pressure of the condensate pump at the lowest economic speed, and g is the acceleration due to gravity.

7. A heating temperature regulation method for reducing power consumption of a condensate pump according to claim 1, characterized in that: The minimum economic speed is a speed at which the flow rate of the condensate pump is greater than 30% of the rated flow rate of the condensate pump.

8. A heating temperature regulation method for reducing power consumption of a condensate pump according to claim 1, characterized in that: When the valve opening is 100% and the heating steam outlet temperature is still higher than 345°C, the alarm is triggered and the booster water pump group is forced to start, and the booster water pump group is used to adjust the heating temperature.

9. A heating temperature regulation method for reducing power consumption of a condensate pump according to claim 1, characterized in that: When the regulating valve opening is lower than 5% and the heating steam outlet temperature is lower than 320℃, close the heating and cooling water regulating valve.

10. A heating device based on the heating temperature regulation method for reducing the power consumption of a condensing pump according to any one of claims 1 to 9, characterized in that: The device comprises: Heating system: generates heating steam and outputs heating steam through heating steam pipelines; Condensate system: provides condensate for cooling; Heating steam pipeline: outputs heating steam to the outside; Desuperheating water boosting module: Based on the data collected by the monitoring module, the condensate pump and booster water pump are dynamically adjusted to pump condensate to the heating steam pipeline to cool the heating steam pipeline; Monitoring module: obtains unit load status, heating steam outlet temperature, heating steam pipeline pressure and condensate pressure.

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