KR100650249B1 - Method for determining the design conditions of heater and deaerator in a thermoelectric power plant - Google Patents

Abstract

The present invention relates to a method for determining feedwater heater and degasser design conditions in a thermal power plant.

The present invention comprises the steps of receiving a pressure and enthalpy for each component by selecting the components in the thermal power plant to determine the design conditions, when switching to the design condition determination mode; And determining and outputting a design pressure and a design temperature of the selected component using pressure and enthalpy, in accordance with the design characteristics.

Therefore, the present invention, when determining the design conditions of the feed water heater and deaerator in a thermal power plant, only the pressure and enthalpy of the power plant components input based on the thermal balance of the thermal power plant for the optimal design of the component By automatically determining the pressure and temperature, it is possible to obtain design conditions such as design pressure and design temperature of a component for optimal design by simple data input, and to shorten the overall design time of the corresponding component, and supply water made of the same structure or material. Even if the system manager or designer changes for the heater and the deaerator, constant design conditions are always determined, which has the effect of designing a high quality thermal power plant.

Description

METHODS FOR DETERMINING THE DESIGN CONDITIONS OF HEATER AND DEAERATOR IN A THERMOELECTRIC POWER PLANT}             

Figure 1 is a block diagram showing the configuration of a system for applying the method for determining the feed water heater and deaerator design conditions in the thermal power plant of the present invention.

Figure 2 is a flow chart showing the operation of the water heater and deaerator design conditions determination method in the thermal power plant of the present invention.

Figure 3 is a flow chart showing the process of determining the design conditions of the low-pressure water heater in the feed water heater and deaerator design condition determination method in the thermal power plant of the present invention.

Figure 4 is a flow chart showing the process of determining the design conditions of the high-pressure water heater in the feed water heater and deaerator design condition determination method in the thermal power plant of the present invention.

Figure 5 is a flow chart showing a process of determining the design conditions of the deaerator and tank in the method of determining the feed water heater and deaerator design conditions in the thermal power plant of the present invention.

Figure 6 is an exemplary view showing an example of a data input window of the design condition change mode in the feed water heater and deaerator design condition determination method in the thermal power plant of the present invention.

Figure 7 is an exemplary view showing an example of the data result window of the design condition change mode in the feed water heater and deaerator design condition determination method in the thermal power plant of the present invention.

*** Description of the symbols for the main parts of the drawings ***

10: key input unit 11: display unit

12 control unit 13 design characteristic storage unit

The present invention relates to a thermal power plant, in particular, when determining the design conditions of the water heater and deaerator in a thermal power plant, only the pressure and enthalpy of the power plant components input based on the thermal balance of the thermal power plant By automatically determining the pressure and temperature for the optimal design of the system, the design conditions such as the design pressure and the design temperature of the component for the optimal design can be obtained by simple data input, and the overall design time of the component is shortened. (2) The present invention relates to a method for determining the design conditions of feedwater heaters and deaerators in a thermal power plant that design a high-quality thermal power plant because a constant design condition is always determined even if the system manager or designer changes the feedwater heater and deaerator made of a material. .

In general, in a coal-fired power plant, a water heater and a degasser are mainly used to increase efficiency of the entire coal-fired power plant by heating steam and water supply by extracting steam from a turbine extraction stage.

That is, if the steam discharged after rotating the turbine in the condenser in the thermal power plant condensed with water, the feed water heater serves to heat the boiler feed water condensed in the condenser to supply to the boiler again.

Here, the water heater includes a low pressure water heater (LP HTR) and a high pressure water heater (HP HTR), wherein the low pressure water heater is positioned before the water pump to expand the low pressure turbine. The feed water is heated with some extracted steam, and the high pressure feed water heater refers to a heater after the feed pump, and the feed water is heated by the extracting steam of the high pressure and medium pressure turbine. In addition to being able to design small, it is possible to improve the power plant efficiency by reducing the heat loss lost by the cooling water.

In addition, the deaerator separates oxygen and non-condensable gases such as carbon dioxide from the feed water circulating in the system, and is responsible for heating and storing the feed water.

However, in the prior art, when design conditions are determined to design a water heater and a deaerator which play an important role in increasing the overall efficiency in a thermal power plant, a separate low pressure water heater, a high pressure water heater, and a deaerator may be used separately. By setting, managing, and calculating the design conditions, the design conditions according to the designer became inconsistent and there was a problem in that constant design condition values could not be maintained for the same feedwater heater and deaerator.

Therefore, the present invention has been proposed to solve the above conventional problems, when determining the design conditions of the water heater and deaerator in a thermal power plant, the power plant components input based on the thermal balance of the thermal power plant Its purpose is to provide a method to automatically determine the pressure and temperature for the optimal design of the component with only the pressure and enthalpy of.

In order to achieve the above object, the present invention includes switching to a design condition determination mode, selecting components in a thermal power plant to determine design conditions, and receiving pressure and enthalpy for each component; According to the design characteristics, it characterized in that it comprises the step of determining and outputting the design pressure and the design temperature of the selected component using the pressure and enthalpy.

Hereinafter, an embodiment according to the present invention will be described in detail with reference to the accompanying drawings.

Figure 1 is a block diagram showing the configuration of a system for applying the method for determining the feed water heater and deaerator design conditions in the thermal power plant of the present invention, as shown, a key input unit for receiving a command or data from the system administrator ( 10), the display unit 11 outputs the processing result of the command or data input through the key input unit 10 or displays various menus, and provides a user interface for processing the command of the system administrator through various menus, When the system is switched to the design condition change mode by moving the menu to determine the design condition of the feed water heater or the deaerator, the water supply to which the pre-stored design characteristics are applied using the pressure and enthalpy determined according to the thermal balance of the thermal power plant. Control unit 12 for determining the design conditions such as the design pressure, design temperature of the heater or deaerator, feed water heater and deaerator It constitutes a design characteristic storage section 13 for storing the design features determined by reflecting the specific characteristics, such as the water supply structure, the material of the opening and the deaerator to the optimal design.

In addition, Figure 2 is a flow chart showing the operation process of the method for determining the feed water heater and deaerator design conditions in the thermal power plant of the present invention, as shown in the figure, the design pressure, the design temperature, etc. Receiving a selection of components in a thermal power plant to determine conditions (S20 and S21); Receiving a pressure and an enthalpy for each of the selected components (S22); In operation S23, a design pressure and a design temperature of the selected component are determined by applying design characteristics to the input pressure and enthalpy.

The present invention can be applied to a thermal power plant, in particular, when determining the design conditions of the feed water heater and deaerator of a thermal power plant, the configuration only by the pressure and enthalpy of the power plant components input based on the thermal balance of the thermal power plant By automatically determining the pressure and temperature for the optimal design of the element, the design conditions such as the design pressure and the design temperature of the component for the optimal design can be obtained by simple data input, and the overall design time of the component is shortened. For feedwater heaters and deaerators of construction or material, constant design conditions are always determined even if the system administrator or designer changes.

In FIG. 1, the key input unit 10 is used by a system administrator to input a command or data, and the display unit 11 outputs a processing result of a command or data input through the key input unit 10, or a design condition change mode. Displays various menus.

The control unit 12 controls the key input unit 10 and the display unit 11 to provide a user interface for processing commands of the system administrator through various menus, and the system is switched to the design condition changing mode by moving the menu. If you want to determine the design condition of the heater or deaerator, read the pre-stored design characteristics in the design characteristic storage unit 13 and use the input pressure and enthalpy according to the thermal balance of the thermal power plant. Determine design conditions such as design pressure, design temperature, etc.

The controller 12 may implement a user interface such as a data input window or a data result window by using an Excel program, which is a commercially available Microsoft Windows application, as a spreadsheet.

In addition, the design characteristic storage unit 13 stores design characteristics determined by reflecting inherent characteristics such as structures, materials, etc. of the feedwater heater and deaerator for optimal design of the feedwater heater and the deaerator, and stores the Moliere chart and the steam table. do.

On the other hand, with reference to the drawings of Figures 3 to 7 attached to the operation process according to the present invention.

In general, since the temperature, pressure, and drainage flow rate of the water heater and the deaerator are determined based on the thermodynamic thermal balance of the turbine cycle in the thermal power plant, in the present invention, the system manager is a water heater or a deaerator. When the system is switched to the design condition change mode by moving a menu through the user interface to determine the design condition of the controller (S20), the control unit 12 provides a data input window as shown in FIG. 6 in the switched design condition change mode. By selecting the component to determine the design conditions from the system administrator (S21).

Then, after receiving the pressure and enthalpy of each component determined according to the thermal balance through the key input unit 10 or data communication (S22), and read from the design characteristic storage unit 13 to the input pressure and enthalpy, respectively. By applying previously stored design characteristics, design conditions such as design pressure, design temperature, etc. of the selected component, that is, the water heater or the deaerator are determined, and the data result window as shown in FIG. 7 is output through the display unit 13 ( S23).

At this time, in consideration of the components that are commonly used in thermal power plants, the data input window of Figure 6 to determine the design conditions for the four low pressure water heaters, three high pressure water heaters, one deaerator and tank Accordingly, in step S21, the system manager selects any one or more components among the components and inputs pressure and enthalpy required to determine design conditions of the corresponding components.

First, as shown in FIG. 3, when the system manager selects a low pressure feedwater heater as a component of a thermal power plant to determine design conditions such as design temperature and design pressure in step S21 (S30), the controller 12 The design conditions are determined in different ways according to the shell or tube. When the design conditions are determined for the shell of the low pressure feedwater heater (S31, S32), the design pressure for optimum design is input. By applying a predetermined reference rate of change to the pressure value is determined by raising the value converted to the gauge pressure by 50 psig (S33), the design temperature is determined by using a Mollier chart to the input temperature value It is displayed on the data result window (S34).

That is, in consideration of the error in the steam pressure discharged through the turbine in the VWO (Valve Wide Open) state, a reference change rate of about 115% is applied to the pressure input in the step (S22), and the result is converted into a gauge pressure. The pressure is determined by rounding up to 50 psig. For example, when the input pressure value is '0.19kg / cm2, a = 2.7 psia', such as the low pressure water heater of FIG. 6, the pressure value is absolute pressure. If this is converted into the gauge pressure to which the standard variation rate is applied according to the following equations (1) and (2), it becomes '-11.6 psig', and the result is rounded up by 50 psi. Likewise, '50 psig = 3.5 kg / cm 2, a '.

Absolute pressure (psia) = gauge pressure (psig) + 14.7 (1)

Design pressure (psig) = 2.7 * 1.15-14.7 (2)

In addition, the design temperature is determined by reading the temperature value corresponding to the design pressure of the shell under isotropic conditions using the Moliere chart, and then raising the value by 10 ° F (10 ° F = 5.56 ° C). do.

In addition, in the case of the tube of the low pressure feed water heater, the design pressure is determined by raising the maximum discharge pressure of COP (Condensate Pump) by 50 psig (S35, S36), and the design temperature is the saturation at the design pressure of the shell. Determined by the temperature (S37), for example, if the maximum COP discharge pressure is '9.28kg / ㎠, a = 132psia', the gauge pressure is '117.3paig' by the formula (1), which is 50psig units When rounded up, the final design pressure is '150 psig', and the design temperature is determined by reading the saturation temperature value of the shell's design pressure using a steam table and rounding it up by 10 ° F.

In addition, the design pressure and the design temperature of the shell and tube of the other low pressure feedwater heater are also determined and displayed by the same method. In the present invention, it is assumed that the low pressure feedwater heaters are designed for three low pressure feedwater heaters.

On the other hand, as shown in Figure 4, in the step (S21) when the system manager selects the high-pressure water supply heater as a component of the thermal power plant to determine the design conditions, such as design temperature and design pressure (S40), the control unit 12 The design conditions are determined in different ways according to the shell or tube. When the design conditions are determined for the shell of the high pressure feedwater heater (S41, S42), the design pressure for the optimum design is entered. It is determined by raising the value converted into gauge pressure by 50 psig by applying a predetermined reference rate of change to the pressure value (S43), and the design temperature is determined by using a Moliere chart according to the shell skirt and the main shell. The value is determined and displayed on the data result window (S44).

Here, the design pressure of the shell is determined in the same manner as in the case of the low pressure feed water heater, and the design temperature of the shell is designed for the shell under isotropic conditions using the Moiréer chart using the input operating pressure and enthalpy value for the shell skirt. After reading the temperature value corresponding to the pressure, increase the value by 10 ° F (= 5.56 ° C) and determine the saturation temperature at the shell's design pressure in the case of the main shell.

And, in the case of determining the design conditions for the tube in the high-pressure water heater, the design pressure is determined by raising the maximum BFP discharge pressure in 50 psig units (S45, S46), and the design temperature is desuperheating area and its The saturation temperature at the design pressure of each shell is determined by dividing it into other areas and displayed in the data result window (S47).

Here, the design temperature of the tube is determined by dividing the overheat prevention zone and the other zones according to the fluid state for the high pressure water heater which is divided into the overheat prevention zone, the subcooling zone, and the condensing zone. Outside the overheat protection zone, the saturation temperature at the design pressure of the shell is read and raised in 10 ° F units using the steam table as in the case of the low pressure water heater, and the design temperature in the overheat protection zone is determined. Determines 35 ° F. (10 ° F. = 5.56 ° C.) higher than the determined design temperature.

Lastly, as shown in FIG. 5, when the system manager selects a deaerator as a component of a thermal power plant to determine design conditions such as a design temperature and a design pressure in step S21 (S50), the control unit 12 is demounted. Determine the design pressure of the shell of the low pressure water heater and the high pressure water heater by the design pressure of the equipment, but increase the value by 25 psig to determine the value (S51, S52). 10 ° F. is added to the determined temperature and then rounded up by 10 ° F. and displayed in the data result window (S53).

And, in the case of a tank integrated with the degasser (S54), in carbon steel (carbon steel) uniformly determine the design temperature to 650 ° F and display it in the data result window (S55).

As described above, the present invention, when determining the design conditions of the feed water heater and degasser in the thermal power plant, only the pressure and enthalpy of the power plant components input based on the thermal balance of the thermal power plant By automatically determining the pressure and temperature for the optimal design, the design conditions such as the design pressure and the design temperature of the component for the optimal design can be obtained by simple data input, and the overall design time of the component is shortened. Even if the system manager or the designer changes for the feedwater heater and the deaerator made of materials, constant design conditions are always determined, which has the effect of designing a high quality thermal power plant.

Claims (5)

When switching to the design condition determination mode, selecting components in a thermal power plant to determine design conditions and receiving pressure and enthalpy for each component; And determining and outputting design pressure and design temperature of the selected component using pressure and enthalpy according to the design characteristics. The method of claim 1, wherein determining and outputting a design pressure and a design temperature of the selected component using pressure and enthalpy according to the design characteristic comprises: inputting the design pressure in the case of a shell of the low pressure water heater. After applying the standard rate of change to the measured pressure value, the value converted to gauge pressure is rounded up by 50 psig, and the design temperature is determined by using a Mollier chart on the input temperature value and displayed on the data result window. In the case of design pressure, the maximum discharge pressure of condensate pump (COP) and boiler feed pump (BFP) is raised by 50 psig, and the design temperature is determined by displaying the saturation temperature at the design pressure of the shell and displaying it. Determination of Design Condition of Feedwater Heater and Deaerator in Power Plant. According to claim 1, The step of determining and outputting the design pressure and the design temperature of the selected component using the pressure and enthalpy according to the design characteristics, in the case of the shell of the high-pressure water heater, the design pressure is the input pressure value Round up the value converted to gauge pressure by 50 psig by applying the standard variation rate to the design temperature, and design temperature is determined and displayed by using Moliere chart according to shell skirt and main shell. In the thermal power plant characterized in that the pressure is raised to the maximum BFP discharge pressure in 50psig unit and the design temperature is determined by the saturation temperature at the shell design pressure divided into the desuperheating area and other areas. Method for Determining Design Conditions of Feedwater Heater and Deaerator According to claim 1, The step of determining and outputting the design pressure and the design temperature of the selected component using the pressure and enthalpy according to the design characteristics, in the case of the degasser, the design pressure is a reference rate of change to the input pressure value By applying, increase the value converted into gauge pressure by 25 psig and design temperature is determined by adding 10 ℉ to 10 ℉ and then designating temperature by using Moliere chart. A method for determining feedwater heater and deaerator design conditions in a thermal power plant, characterized in that the design temperature is determined and displayed at 650 ° F. in carbon steel. The water supply in a thermal power plant according to any one of claims 2 to 4, wherein the reference variation rate is 115% of the steam pressure discharged through the turbine in a VWO (Valve Wide Open) state. How to determine heat and deaerator design conditions.

Images