CN111612308B - A General Calculation Method for Evaluating Coal Consumption Index of Coal-fired Heating Units - Google Patents

Abstract

The invention discloses a general calculation method for evaluating coal consumption indexes of a coal-fired heat supply unit, and relates to the technical field of energy and power production; the method comprises the steps of S1, calculating the thermalization power generation rate of a heat supply unit, S2, calculating the power generation heat consumption of the heat supply unit, S3, calculating the power generation efficiency of the heat supply unit and S4, calculating the power generation coal consumption of the heat supply unit; the coal consumption of the coal-fired heat supply unit is evaluated by the steps of calculating the thermalization power generation rate of the heat supply unit by S1, calculating the power generation heat consumption of the heat supply unit by S2, calculating the power generation efficiency of the heat supply unit by S3, calculating the power generation coal consumption of the heat supply unit by S4 and the like.

Description

A General Calculation Method for Evaluating Coal Consumption Index of Coal-fired Heating Units

technical field

The invention relates to the technical field of energy and electric power production, in particular to a general calculation method for evaluating the coal consumption index of a coal-fired heating unit.

Background technique

At present, more than half of the coal in my country is used to produce electricity. The huge consumption of coal has brought serious environmental pressure. In the process of electricity production, the coal consumption index of thermal power units is an index that indicates the technical perfection of the energy conversion process of the power plant. The comprehensive index is both a quantitative index and a quality index. The algorithm is simple, but for the heating unit, it uses part of the steam that has done work in the steam turbine to supply heat to the outside. The quality of the two products is different. Different parameters lead to different heating quality. It is urgent to find a method that can comprehensively evaluate the technical perfection of the cogeneration production process. For comparison, the calculation method is concise technical indicators. Using this index can reasonably evaluate the technology, management and operation level of existing coal-fired power plants, and can also be used to guide the selection of technical parameters and equipment selection of new units, and promote the active adoption of new energy-saving technologies in power plants, greatly improving the efficiency of units. Thermal efficiency.

Traditionally, in order to calculate various economic indicators of coal-fired power plants, the power industry has specially formulated the "Calculation Method of Technical and Economic Indicators of Thermal Power Plants" (DL/T 904-2015), which provides the calculation of various technical and economic indicators of thermal power plants method. The efficiency index η, which evaluates the coal-fired efficiency of thermal power plants in this standard, is established based on the first law of thermodynamics. It can also reflect the energy conversion efficiency of the unit, which is a comprehensive index. For the heating unit, the calculation result is the ratio of the total energy of the two products of heat and electricity to the input energy of coal combustion, and the high-grade electric energy is converted into heat units. After 3600W is added to the low-grade heat supply, the difference in grade between heat and electricity cannot be distinguished. The calculation formula is:

In the formula, W-generating capacity of heating unit, kWh;

Q- heat supply of heating unit, kJ/h;

B- Coal consumption of heating unit, kg/h.

There are three problems with the calculation results:

1. With different heating steam parameters and under the same heat supply conditions, the coal consumption of the same type of unit will have a large difference.

2. When the same type of unit is supplied and the hot steam parameters are the same, the coal consumption under different heat supply is also very different.

3. Even if it is the most advanced super (super) critical unit, its coal consumption cannot be compared with that of a small back pressure unit.

In addition to causing unfairness in the evaluation process, it will also have a certain impact on the energy efficiency evaluation of new thermal power unit projects.

The calorimetric method assigns all the energy-saving heat economic benefits of cogeneration to power generation, making heat users require high heating parameters, resulting in the assumption of high heating costs and wasting national energy. The actual enthalpy drop method assigns all the thermal economic benefits of cogeneration to heating. Although it takes into account the difference in the quality of heating steam, heating is not equal to work; Apportionment, the actual enthalpy drop method is corrected. Some scholars believe that fire has no method, and they have not considered the role of fire in heat supply. The result is still beneficial to heat supply and not conducive to power generation, and it is not suitable. It doesn't work at all (exergy method), thus a combined thermoelectric method is proposed. Some scholars believe that the distribution of Qtp should not only improve the heating efficiency from the "hot end", but also fully consider the "cold end" (including the grade of heating, the connection method between heat users and the heating network, and the heat exchange equipment for heat use, etc.) , put forward the apportionment method of the unit consumption of cogeneration heating, and should try to minimize the "artificial regulation" to a minimum. There are too many such documents and will not be listed. It can be seen that theoretically discussing the rational distribution of Qtp is still one of the theoretical issues to be solved urgently in the development of the heating industry.

Based on this, it is necessary to establish a new coal combustion index or efficiency calculation method for heating units. Through this method, the power supply coal consumption of the combined heat and power unit is converted into the power supply coal consumption in the corresponding pure condensation state, which can effectively eliminate The heat and power cogeneration unit has an impact on the power supply coal consumption of the unit due to the amount of heat supplied and the level of steam extraction parameters.

China Electricity Union Science and Technology [2014] No. 219 "National Thermal Power Coal-fired Units Competition Evaluation Management Measures" (2014 Edition) stipulates that the national thermal power coal-fired large-scale competition technical plan for the calculation and correction method of coal consumption for different types of units:

Coal consumption for power supply = annual standard coal consumption/power supply -72*industrial extraction pressure correction factor*industrial heat-to-electricity ratio-82.8*heating extraction pressure correction factor*heating heat-to-electricity ratio

S4 and S5 are correction coefficients of steam extraction pressure for industrial heating and heating heating respectively.

This method is simple and easy to operate in practice, and has strong operability, and it also has certain theoretical support. However, the source of the correction coefficient for industrial steam extraction and heating extraction lacks reliable theoretical demonstration.

Existing technical problems and thinking:

How to solve the technical problem of evaluating the coal consumption of coal-fired heating units.

Contents of the invention

The technical problem to be solved by the present invention is to provide a general calculation method for evaluating the coal consumption index of coal-fired heating units, which uses S1 to calculate the thermal power generation rate of the heating units, S2 to calculate the power generation heat consumption of the heating units, and S3 to calculate the heating units The power generation efficiency and the steps of calculating the coal consumption of the heating unit for power generation in S4 realize the evaluation of the coal consumption of the coal-fired heating unit.

In order to solve the above technical problems, the technical solution adopted by the present invention is: a general calculation method for evaluating the coal consumption index of a coal-fired heating unit, including S1 calculating the thermal power generation rate of the heating unit, S2 calculating the heat consumption of the heating unit for power generation, and S3 Calculating the power generation efficiency of the heating unit and the step of calculating the coal consumption of the heating unit in S4, in the step of calculating the heat consumption of the heating unit in S2,

In Equation 4: q _tp —heat consumption of power generation, kJ/kWh; Q _tp —heat consumption of unit, GJ/h; Pe—actual output electric power of the unit, kW; W _h —thermal equivalent power of the unit, kW .

A further technical solution is: in the step of calculating the thermal power generation rate of the heating unit in S1,

In formula 1: ω——thermalization power generation rate, kWh/GJ; h _o ——new steam enthalpy, kJ/kg; h _h ——heat supply and extraction steam enthalpy, kJ/kg; h'h——heat supply return Specific enthalpy of water, kJ/kg; η _m η _g —mechanical efficiency of the generator, %; e——relative thermal power generation share, %.

A further technical solution is: in formula 1, e is the ratio of internal and external thermal power generation,

——内部热化发电功率，kW；

——外部热化发电功率，kW；D_im——假想回热抽汽量，kg/h；D_h.t——供热抽汽量，kg/h；h_im——假想混合式加热器的加热蒸汽比焓，kJ/kg；h'_im——假想混合式加热器的蒸汽凝结水焓，kJ/k；h_fw——给水焓，kJ/kg；

——返回水焓，kJ/kg。In formula 2:

——internal heating power generation, kW;

——external thermal power generation power, kW; D _im ——imaginary regenerative steam extraction capacity, kg/h; D _ht ——heating extraction steam amount, kg/h; h _im ——imaginary hybrid heater heating Steam specific enthalpy, kJ/kg; h' _im —— steam condensate enthalpy of imaginary hybrid heater, kJ/k; h _{fw ——feed} water enthalpy, kJ/kg;

——return water enthalpy, kJ/kg.

Further technical solutions are:

W _h = Q _h ω (3)

In formula 3: W _h —— thermal equivalent power, kW; Q _h —— heat supply, GJ/h.

A further technical solution is: in the step of calculating the power generation efficiency of the heating unit in S3,

In Formula 5: η _{tp ——thermal} efficiency of power generation, %.

A further technical solution is: in the step of calculating the coal consumption of the heating unit for power generation in S4,

In formula 6: b _tp - coal consumption for power generation, g/kWh.

A further technical solution is to manually execute the steps of S1 calculating the thermal power generation rate of the heating unit, S2 calculating the heat consumption of the heating unit for power generation, S3 calculating the power generation efficiency of the heating unit, and S4 calculating the coal consumption of the heating unit for power generation.

A further technical solution lies in: calculating the thermal power generation rate of the heating unit by running S1 through the computer, calculating the heat consumption of the heating unit in S2, calculating the power generation efficiency of the heating unit in S3, and calculating the coal consumption of the heating unit in S4.

A further technical solution is to display calculation results through a display connected to a computer.

A further technical solution is to print the calculation results through a printer connected to the computer.

The beneficial effects produced by adopting the above-mentioned technical scheme are:

It realizes the evaluation of coal consumption of coal-fired heating units by calculating the thermal power generation rate of heating units in S1, calculating the heat consumption of power generation in S2, calculating the power generation efficiency in S3, and calculating the coal consumption in power generation in S4.

For details, see the description in the specific implementation mode.

Description of drawings

Fig. 1 is a flow chart of the present invention;

Fig. 2 is a schematic block diagram of the steam extraction heat supply generating set;

Fig. 3 is a functional block diagram of a back pressure heating generator set;

Figure 4 is a T-S diagram of the Rankine cycle and the heating cycle.

detailed description

The following will clearly and completely describe the technical solutions in the embodiments of the application with reference to the drawings in the embodiments of the application. Apparently, the described embodiments are only some of the embodiments of the application, not all of them. The following description of at least one exemplary embodiment is merely illustrative in nature and in no way serves as any limitation of the application, its application or uses. Based on the embodiments in this application, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of this application.

In the following description, a lot of specific details are set forth in order to fully understand the application, but the application can also be implemented in other ways different from those described here, and those skilled in the art can do without violating the connotation of the application. By analogy, the present application is therefore not limited by the specific embodiments disclosed below.

As shown in Figure 1, the present invention discloses a general calculation method for evaluating the coal consumption index of a coal-fired heating unit, specifically as follows:

S1 Calculation of thermal power generation rate of heating unit

In Formula 1:

ω——heating power generation rate, kWh/GJ;

h _o — new steam enthalpy, kJ/kg;

h _h ——Heating extraction steam enthalpy, kJ/kg;

h' _h - specific enthalpy of heat supply and return water, kJ/kg;

η _m η _g ——generator mechanical efficiency, %;

e——The share of relative thermal power generation, %.

where e is the ratio of internal to external thermal power generation.

In formula 2:

——内部热化发电功率，kW；

——internal heating power generation, kW;

——外部热化发电功率，kW；

——External thermal power generation, kW;

D _im ——imaginary regenerative steam extraction capacity, kg/h;

D _ht ——heat extraction steam capacity, kg/h;

h _im ——heating steam specific enthalpy of imaginary hybrid heater, kJ/kg;

h' _im ——the steam condensate enthalpy of imaginary hybrid heater, kJ/k;

h _{fw ——feed} water enthalpy, kJ/kg;

——返回水焓，kJ/kg。

——return water enthalpy, kJ/kg.

W _h = Q _h ω (3)

In formula 3:

W _h — thermal equivalent power, kW;

Q _h - heat supply, GJ/h.

S2 calculates the heat consumption of the heating unit for power generation

In formula 4:

q _{tp ——heat} consumption of power generation, kJ/kWh;

Q _tp ——heat consumption of unit, GJ/h;

Pe - the actual output electric power of the unit, kW;

W _h ——heating equivalent power of the unit, kW.

S3 calculates the power generation efficiency of the heating unit

In Formula 5:

η _{tp ——thermal} efficiency of power generation, %.

S4 Calculation of coal consumption for power generation of heating units

In formula 6:

b _tp —coal consumption for power generation, g/kWh.

Purpose of this application:

A new coal-fired calculation correction method is proposed, which has both the concept of quantity and the concept of quality, and can comprehensively reflect the technical perfection of the energy conversion process of different types of coal-fired steam turbine units. The technical and economical comparison of heating units can also accurately evaluate the technical and economical performance of different heating units, which is convenient for industry benchmarking and index competitions. The method is simple and practical.

The inventive concept of the application:

The essence of thermal power plant production is energy conversion, that is, the chemical energy in the fuel is converted into heat energy of steam through combustion in the boiler, and converted into mechanical energy through the rotation of the steam turbine, and finally converted into the required electrical energy through the generator. my country's thermal power plants use the calorimetric method to quantitatively evaluate their thermal economy. The commonly used thermal economic indicators mainly include energy consumption measured per hour and per year, including steam consumption, heat consumption and coal consumption; measured per kW·h or MW·h The energy consumption rate, including steam consumption rate, heat consumption rate and coal consumption rate; the thermal efficiency measured as a percentage, the object of measurement is the steam turbine generator set or the entire power plant.

The standard coal consumption rate reflects the technical perfection of the energy conversion process of a power plant or generating set, and is also a comprehensive index reflecting its management level and operation level. one of the important indicators.

As shown in Figure 2 and Figure 3, there are two types of production forms of thermal power plants: heat and electricity separate production and heat and power cogeneration. Industrial boilers or heating hot water boilers and even civil stoves produce heat to heat users, also known as single energy production, that is, only one kind of energy is supplied, electric energy or heat energy. Combined heat and power energy production is referred to as combined heat and power or thermalization. It converts the chemical energy of fuel into high-grade thermal energy for power generation, and at the same time converts part of the work done in the heating turbine to generate electricity or thermal power generation. The final low-grade heat energy is used for external heating.

As shown in Figure 4, it is the enthalpy and entropy diagram of the thermodynamic cycle of the pure condensing power unit and the heating unit. The left (a) is the Rankine cycle, and the left (b) is the heating cycle. It can be seen that the η of the heating cycle _th and η _ih are both 1, because not only the ideal exhaust heat q _ha , but also the irreversible heat loss Δqh of steam work are all used for external heat supply, and it has no heat loss from cold source like Rankine cycle at all, so it can be large The thermal economy of the thermal power plant can be greatly improved, and the heat consumption rate and coal consumption rate can be greatly reduced accordingly. Calculation shows that the value of η _tp (e) of heating unit calculated by calorimetric method is much higher than that of Rankine cycle with the same parameters.

The heat supply steam turbine has different forms such as single pumping C type or double pumping CC type condensing steam turbine, back pressure type B type or pumping back type CB type. It should be pointed out that, for the steam extraction type, only the heating steam flow Dh that generates electricity first and then heats it belongs to cogeneration, while its condensing steam flow Dc still belongs to separate power generation. The definition of combined heat and power by the European Cogeneration Alliance is: From a dynamic point of view, cogeneration is a primary energy system that sequentially produces two or more forms of energy.

According to the traditional definition, a series of comprehensive indicators need to be used to evaluate the economics of heating units and thermal power plants, including fuel utilization coefficient, thermal power generation rate, heat-to-power ratio, coal consumption for power generation, coal consumption for power supply, and coal consumption for heating, among which the standard coal consumption is only It is a quantitative index, and the coal consumption index we require is a comprehensive index indicating the technical perfection of the power plant's energy conversion process. It is both a quantitative index and a quality index. , thermal power plants, and it is also convenient to compare between condensing power plants and thermal power plants.

Basic definition of heat consumption of generator set:

In the formula:

q——heat consumption of power generation, kJ/kWh;

Q——heat consumption of unit, GJ/h;

P——the output electric power of the unit, kW.

In the heat consumption rate of the heating unit calculated by the calorimetric method, since the heat supply is subtracted from the heat consumption of the whole unit, it is replaced by the sum of the energy of the pure condensing steam flow and the heating steam flow without loss of the cold source. The benefits of production all belong to power generation. Compared with pure condensing generating units, with the increase of heat supply, the coal consumption for power generation calculated by heating units has dropped significantly, which cannot normally reflect the real equipment level and management level.

The feature of this application proposes to use the heating steam flow to calculate the equivalent coal consumption of the heating unit according to the degree of perfection of the unit and the power generation capacity of the thermal cycle, that is, the thermal equivalent power.

The equivalent coal consumption index is based on the second law of thermodynamics, considering the influence of different heating parameters, quality and work ability on coal consumption.

Using this index can reasonably evaluate the technology, management and operation level of existing power plants, and can also be used to guide the selection of technical parameters and equipment selection of new units, and promote the active adoption of new energy-saving technologies in power plants to greatly improve the thermal efficiency of units.

Technical contributions of this application:

A general calculation method for evaluating the coal consumption index of coal-fired heating units is as follows:

1. First calculate the thermal power generation rate of the heating unit:

The thermal power generation rate is the thermal power generation per GJ, which represents the technical perfection of the combined heat and power generation, and is only related to the heat and electricity of the co-generation part. The thermal equivalent power of the unit is calculated through the thermal power generation rate, which is the heating energy converted into achievable power generation.

In Formula 1:

ω——heating power generation rate, kWh/GJ;

h _o — new steam enthalpy, kJ/kg;

h _h ——Heating extraction steam enthalpy, kJ/kg;

h' _h - specific enthalpy of heat supply and return water, kJ/kg;

η _m η _g ——generator mechanical efficiency, %;

e——The share of relative thermal power generation, %.

where e is the ratio of internal to external thermal power generation.

In formula 2:

——内部热化发电功率，kW；

——internal heating power generation, kW;

——外部热化发电功率，kW；

——External thermal power generation, kW;

D _im ——imaginary regenerative steam extraction capacity, kg/h;

D _ht ——heat extraction steam capacity, kg/h;

h _im ——heating steam specific enthalpy of imaginary hybrid heater, kJ/kg;

h' _im ——the steam condensate enthalpy of imaginary hybrid heater, kJ/k;

h _{fw ——feed} water enthalpy, kJ/kg;

——返回水焓，kJ/kg。

——return water enthalpy, kJ/kg.

W _h = Q _h ω (3)

In formula 3:

W _h — thermal equivalent power, kW;

Q _h - heat supply, GJ/h.

2. Then calculate the heat consumption of the heating unit for power generation:

In formula 4:

q _{tp ——heat} consumption of power generation, kJ/kWh;

Q _tp ——heat consumption of unit, GJ/h;

Pe - the actual output electric power of the unit, kW;

W _h ——heating equivalent power of the unit, kW.

3. Recalculate the power generation efficiency of the heating unit:

In Formula 5:

η _{tp ——thermal} efficiency of power generation, %.

4. Finally, calculate the coal consumption of the heating unit for power generation:

In formula 6:

b _tp —coal consumption for power generation, g/kWh.

The calculation method introduces the concept of thermal equivalent power. In the traditional calculation method, even if the heating steam parameters of the same type of unit are the same, the calculated coal consumption for power supply due to the different heat supply is also very different, and the calculation results cannot be true. It reflects the technical level and management level of the actual equipment of the power plant. An extreme example is that due to the very large heat supply ratio, the coal consumption of small back pressure thermal power units is much lower than that of the most advanced supercritical units at present, but in fact, Regardless of the technical level of its equipment or the level of power plant operation and management, it cannot be compared with the current large supercritical units. In addition to causing unfairness in the evaluation process, it will also have a certain impact on the energy efficiency evaluation of new thermal power unit projects.

After replacing the actual generating power Pe of the unit with Pe+W _h , since the thermalization power generation rate ω is the thermalization of each gigajoule based on the heating cycle, that is, the combined heat and power generation, this calculation index shows that the combined heat and power generation technical sophistication.

The traditional calorimetric method attributes all the benefits of cogeneration to power generation, while the actual enthalpy drop method attributes all the benefits to heating. Although the working capacity method is between the two, due to the exhaust temperature of the heating turbine and the environment The temperature difference is small, and the heating coal consumption calculated by the sequential method is close to the actual enthalpy drop method, which also attributes most of the benefits of cogeneration to heating, and the coal consumption rate of the heating unit for power generation is still higher than that of the condensing type in the power system. Units and thermal power companies still cannot accept this method of heat distribution, which is not conducive to the development of combined heat and power generation, and is not conducive to the country's energy conservation and improvement of the ecological environment.

Description of technical solution:

By extracting the coal, electricity, steam, water and other parameters in the production process of power generation enterprises or generating units, it is possible to calculate the real-time coal consumption of a single device, and also conduct annual and monthly statistical analysis and calculation of the whole plant or a single device to obtain the average power consumption. Or power supply coal consumption value.

Calculation example 1:

A thermal power plant is equipped with a C50-8.83/0.118 single-extraction heating unit, p _o = 8.83MPa, t _o = 535°C, h _o = 3475.04kJ/kg, S _o = 6.7801kJ/(kg.k). Heating regulation extraction steam pressure p _h ＝0.118MPa, actual extraction steam specific enthalpy h _h ＝2620.52kJ/kg, return water specific enthalpy _h ' _h ＝334.94kJ/kg(80℃), Sh ＝7.1410kJ/(kg. k), water return rate φ = 100%, η _hs = 0.97. Minimum condensate flow rate Dc=17000kg/h, actual exhaust steam specific enthalpy hc=2391.5kJ/kg, feed water specific enthalpy 315.7kJ/kg, condensate water specific enthalpy h _c '=97.3kJ/kg, η' _b =η _b η _p = 0.88, η _mg = η _m η _g = 0.98. The annual utilization hours of heating heat load ζ=4000h, Ten=273.15K.

Find the coal consumption for power generation of this unit.

1. Steam consumption D _o ＝(3600P _e /η _mg -D _c (h _h -h _c )/(h _o -h _h )＝(3600*5000/0.98-17000*(2620.52-2391.5)/(3475.04 -2620.52) = 210387 kg/h.

2. Heating and steam extraction = D _o -D _c = 210387-17000 = 193387kg/h.

3. Total heat consumption Q _tp =(D _o (h _o -h _fw ))/(η _b η _p *10 ⁶ )=755.31GJ/h.

4. Heat supply Q _h =D _h (h _h -h' _h )*10 ^-6 =193387*(2620.52-334.94)*10 ^-6 =442GJ/h.

5. Thermal power generation rate ω=278(h _o -h _h )η _mg /(h _h -h' _h )=278(3475.04-2620.52)*0.98/(2620.52-334.94)=101.86kWh/GJ.

6. Thermal power generation power W _h =442*101.86=45022.12kW.

7. Heat consumption of power generation=Q _tp /(P+W _h )=755.31/(50000+45022.12)=7948.79kJ/kW.

8. Thermal efficiency of power generation η _tp = 3600/7948.9 = 45.29%.

9. Coal consumption for power generation b _tp =123/η _tp =123/0.4529=271.58g/kWh.

As shown in Table 1, the results obtained by using this method are between the calorimetric method and the working capacity method. The benefits of the calorimetric method belong to electricity, which does not fully reflect the technical level of cogeneration and the quality of heat supply. The calculated coal consumption for power generation Low, although it can stimulate the development of cogeneration business, it is not conducive to the further technical upgrading of cogeneration units and the potential of energy saving. Only by greatly increasing the heat supply, the coal consumption of power generation can be reduced, and it is not conducive to fair and just competition .

Table 1: Calculation results of thermal economic indicators by traditional three allocation methods

Calculation example 2:

A 300MW heat and power cogeneration steam turbine unit, the unit model is C330/258-16.7/0.55/537/537, the annual coal consumption is 931851t, the average low calorific value of coal is 19771kJ/kg, the annual heat supply is 2577570GJ, and the power generation is 1865.91 million kWh , power supply 1,738.85 million kWh, heating parameters: heating extraction pressure/temperature 0.43MPa/264.3℃, heating supply/return water temperature 84, 65℃, supply and return water pressure 0.8/0.2MPa respectively.

Calculation results:

①The rules of the CEC unit competition

Coal consumption for power generation=annual standard coal consumption/power generation-72*industrial extraction pressure correction factor*industrial thermoelectricity ratio-82.8*heating extraction pressure correction coefficient*heating thermoelectricity ratio=931851000*19771/(29310*1856910000)-82.8 *1.45*2577570/(186591*36)＝290.83kg/kWh.

②Calorimetric method

Coal consumption for power generation = (931851000*19771/29310-2577570*40)/1865910000=281.6g/kWh.

③Equivalent power method

Thermal power generation rate=278(3394.12-2993.01)*0.98/(2993.01-272.17)=40.16kWh/GJ.

Coal consumption for power generation=(931851000*19771/29310)/(1865910000+2577570*40.16)=319g/kWh.

After the application has been kept secret for a period of time, the feedback from the on-site technicians is beneficial:

The calculation method is simple and practical, and it establishes a unified benchmark for the economic comparison of different types of thermal power units. The economy between thermal units, thermal power plants, condensing steam units and heating units encourages power generation companies to not only improve the comprehensive utilization rate of energy through cogeneration, but also pay attention to technological progress and improve thermal power conversion efficiency. Especially in recent years, the coal consumption competition of large-scale steam turbine units carried out nationwide must not only consider the efficiency of energy utilization of cogeneration units, but also make the heating load moderately reflected, and it is not possible to reduce the coal consumption of power generation by simply increasing the heating load. index.

Claims (7)

1. A general calculation method for evaluating coal consumption indexes of a coal-fired heat supply unit is characterized by comprising the following steps: comprises the steps of S1 calculating the thermalization power generation rate of the heat supply unit, S2 calculating the power generation heat consumption of the heat supply unit, S3 calculating the power generation efficiency of the heat supply unit and S4 calculating the power generation coal consumption of the heat supply unit,

in the step of calculating the thermalization power generation rate of the heating unit in S1,

in formula 1: omega-thermalization Generation, kWh/GJ; h is a total of _o -new steam enthalpy, kJ/kg; h is _h -enthalpy of heat extraction, kJ/kg; h' _h -specific enthalpy of return heat supply, kJ/kg; eta _m η _g -generator mechanical efficiency,%; e-relative thermalization power generation fraction,%;

in the step of calculating the power generation heat consumption of the heat supply unit S2,

in formula 4: q. q.s _tp -power generation heat consumption, kJ/kWh; q _tp -unit heat consumption, GJ/h; pe-actual output electric power of the unit, kW; w is a group of _h -unit thermalization equivalent power, kW;

in the step of calculating the generating efficiency of the heating unit S3,

in formula 5: eta _tp -generating thermal efficiency,%;

in the step of calculating the coal consumption of the heat supply unit in S4,

in formula 6: b _tp -electricity generation coal consumption, g/kWh.

2. The general calculation method for evaluating the coal consumption index of the coal-fired heat supply unit according to claim 1, characterized by comprising the following steps: where e in formula 1 is the ratio of internal to external thermalization generation,

in formula 2:

-internal thermalization power generation, kW;

-external thermalization power generation, kW; d _im The regenerative steam extraction amount is assumed to be kg/h; d _h.t -the amount of heat supply extraction, kg/h; h is a total of _im -specific enthalpy of heating steam, kJ/kg, for the hypothetical hybrid heater; h is _i ' _m -assuming steam condensate enthalpy, kJ/k, for the hybrid heater; h is _fw -feed water enthalpy, kJ/kg;

-return water enthalpy, kJ/kg.

3. The general calculation method for evaluating the coal consumption index of the coal-fired heat supply unit according to claim 1, characterized by comprising the following steps: w _h ＝Q _h ω(3)

In formula 3: w is a group of _h -thermalization equivalent power, kW; q _h -heat supply, GJ/h.

4. The general calculation method for evaluating the coal consumption index of the coal-fired heat supply unit according to claim 1, characterized by comprising the following steps: and manually executing the steps of S1 calculating the thermalization power generation rate of the heat supply unit, S2 calculating the power generation heat consumption of the heat supply unit, S3 calculating the power generation efficiency of the heat supply unit and S4 calculating the power generation coal consumption of the heat supply unit.

5. The general calculation method for evaluating the coal consumption index of the coal-fired heat supply unit according to claim 1, characterized by comprising the following steps: and operating the computer to calculate the thermalization power generation rate of the heat supply unit by S1, calculating the power generation heat consumption of the heat supply unit by S2, calculating the power generation efficiency of the heat supply unit by S3 and calculating the power generation coal consumption of the heat supply unit by S4.

6. The general calculation method for evaluating the coal consumption index of the coal-fired heat supply unit according to claim 5, is characterized in that: and displaying the calculation result through a display connected with the computer.

7. The general calculation method for evaluating the coal consumption index of the coal-fired heat supply unit according to claim 5, is characterized in that: the calculation result is printed by a printer connected to the computer.

Images