Method and system for acquiring carbon dioxide emission of coal-fired unit

Abstract

The invention discloses a coal-fired unit carbon dioxide emission obtaining method and system, and relates to the technical field of carbon dioxide emission. The method comprises the steps that the total output heat of a boiler and the total coal feeding amount of the coal-fired unit are obtained, then the calculation value of the calorific value of unit mass coal of the coal-fired unit is obtained through calculation, and the calculation value of the calorific value of unit mass coal of the coal-fired unit is compared with the mathematical relation of the unit fire coal carbon content-calorific value preset in a database; and then, the carbon dioxide emission amount of the coal-fired unit is obtained through calculation. According to the method, the carbon dioxide emission amount of the coal-fired unit can be obtained under the condition that coal as fired quality testing is not carried out or even carbon oxidation rate related information is not needed, the real-time performance and accuracy are met, and powerful support is provided for calculation and monitoring of the carbon dioxide emission amount of the unit.

Description

Technical Field

[0001] The present invention belongs to the technical field of carbon emission, and in particular to a method and system for obtaining carbon dioxide emissions from a coal-fired unit. Background Art

[0002] Accurately measuring carbon emissions is the basis for carbon reduction and the foundation for the safe, orderly, and stable operation of the carbon market. Currently, there are three main technical approaches to measuring carbon emissions: the first is the material balance method, which is based on elemental analysis of coal and consumption calculations. However, this method suffers from issues such as coal quality fluctuations and verification lags, making it difficult to achieve real-time performance over shorter timescales. For example, Chinese patent publication CN115343417A discloses a method for calculating carbon emissions from coal-fired units. However, due to large statistical errors in coal consumption, its calculation of real-time carbon emissions from coal-fired units is quite limited. The second method is the flue gas monitoring method, which calculates carbon emissions by measuring flue gas flow and CO2 concentration. However, there are technical difficulties such as the difficulty in accurately measuring flue gas flow and CO2 content in large-scale, high-humidity, and multi-component chimneys. For example, (1) the Chinese patent document with publication number CN204649246U proposes a continuous carbon emission monitoring system for coal-fired power plants, but the system needs to add a flue gas flow calculation method for continuous carbon emission monitoring and cannot directly measure the carbon emissions of coal-fired power plants. (2) The Chinese patent document with publication number CN116401492A proposes a real-time monitoring and control system for carbon emissions of coal-fired units, but the accuracy of the measured carbon emissions needs to be verified. The third type is the AI ​​prediction model, which uses methods such as neural networks to predict carbon emissions. However, it is limited by the quality of training data and sudden changes in the unit's operating status, and has problems such as insufficient model generalization ability. For example, the Chinese patent document with publication number CN117591906A proposes a dynamic carbon emission factor calculation method based on coal-fired unit operating data. This method relies on the extensiveness of the unit's historical data, and the calculation results have limitations.

[0003] In summary, providing a method for accurately obtaining the carbon emissions of coal-fired units in real time is an urgent problem to be solved by those skilled in the art.

[0004] The information disclosed in this Background Art is only for understanding the background of the present inventive concept and therefore it may include information that does not constitute prior art. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a method and system for obtaining carbon dioxide emissions from coal-fired units, so as to solve the problem that existing coal-fired unit carbon dioxide emission monitoring technology is difficult to achieve accurate online real-time measurement.

[0006] To this end, the present invention adopts the following technical solutions.

[0007] In a first aspect, the present invention provides a method for obtaining carbon dioxide emissions from a coal-fired unit, comprising:

[0008] Obtain the total heat output of the boiler and the total coal supply of the coal-fired unit, and calculate the estimated calorific value of the unit mass of coal in the coal-fired unit;

[0009] Compare the estimated calorific value per unit mass of coal for the coal-fired unit with the preset mathematical relationship between carbon content and calorific value of the unit's coal in the database to obtain the estimated carbon content of the unit's incoming coal;

[0010] The carbon dioxide emissions of the coal-fired unit are further calculated based on the estimated carbon content of the coal entering the unit.

[0011] The process of obtaining the carbon dioxide emission of the coal-fired unit according to the present invention does not involve real-time chemical testing of the combustion coal quality, and is convenient and accurate.

[0012] Furthermore, the effective heat output and heat loss of the boiler are obtained, and the sum of the two is obtained to obtain the total heat output of the boiler; or the total heat output of the boiler is obtained by dividing the effective heat output of the boiler by the thermal efficiency of the boiler.

[0013] Furthermore, the calorific value per unit mass of coal in the coal-fired unit is calculated as follows:

[0014]

[0015] Where Q coal Q is the estimated calorific value of coal per unit mass in coal-fired units; total is the total heat output of the boiler; M coal It is the total coal supply of coal-fired units.

[0016] Furthermore, a database of the mathematical relationship between the carbon content and calorific value of coal fired by a preset unit is established based on the historical coal quality test data of the commonly used coal types of coal-fired units. The mathematical relationship between the carbon content and calorific value of coal fired by a preset unit is expressed as: C C =f(Q),C C is the carbon content of the coal used in the unit, and Q is the calorific value of the coal per unit mass in the coal-fired unit.

[0017] Furthermore, the mathematical relationship between the carbon content and calorific value of the coal fired unit is simplified to C C ~f(Q) linear function relationship; the calorific value per unit mass of coal in the coal-fired unit is estimated to be Q coal As the Q value, C calculated using the linear function relationship C The value is used as the estimated value of the carbon content of the coal fed into the unit. At this time, the carbon dioxide emissions of the coal-fired unit are calculated using the following formula:

[0018]

[0019] Where, is the carbon dioxide emission of coal-fired units; η cor is the carbon oxidation rate of coal; M coal is the total coal supply of the coal-fired unit; a is the linear fitting slope constant of the linear function relationship; b is the linear fitting intercept constant of the linear function relationship; is the molecular weight of carbon dioxide; Mr c is the molecular weight of carbon atoms.

[0020] Furthermore, the heat loss Q of boiler ash is not included in the heat loss of boiler. hz And the heat loss Q of the boiler stone coal szm , the carbon dioxide emissions of coal-fired units are calculated using the following formula:

[0021]

[0022] Where Q tot Does not include Q hz and Q szm The total heat output of the boiler.

[0023] Furthermore, the coal feeding amount of each coal feeder of the unit is obtained through a measuring device, and then the total coal feeding amount of the coal-fired unit is calculated.

[0024] In a second aspect, the present invention provides a system for obtaining carbon dioxide emissions from a coal-fired unit, which is used to implement the above-mentioned method for obtaining carbon dioxide emissions from a coal-fired unit, and comprises:

[0025] Unit unit coal calorific value calculation unit: used to calculate the calorific value of the unit coal by using the total heat output of the boiler and the total coal supply of the coal-fired unit;

[0026] The unit's coal carbon content estimated value acquisition unit is used to compare the estimated calorific value of the coal per unit mass of the coal-fired unit with the unit's coal carbon content-calorific value mathematical relationship preset in the database to obtain the unit's furnace-input coal carbon content estimated value;

[0027] Coal-fired unit carbon dioxide emissions calculation unit: used to calculate the coal-fired unit carbon dioxide emissions based on the estimated value of the carbon content of the coal entering the furnace of the unit.

[0028] Furthermore, the mathematical relationship between the carbon content and calorific value of the coal fired unit is simplified to C C ~f(Q) linear function relationship; the calorific value per unit mass of coal in the coal-fired unit is estimated to be Q coal As the Q value, C calculated using the linear function relationship C The value is used as the estimated value of the carbon content of the coal fed into the unit. At this time, the carbon dioxide emissions of the coal-fired unit are calculated using the following formula:

[0029]

[0030] Where, is the carbon dioxide emissions from coal-fired units; is the carbon oxidation rate of coal; Q total is the total heat output of the boiler; M coal is the total coal supply of the coal-fired unit; a is the linear fitting slope constant of the linear function relationship; b is the linear fitting intercept constant of the linear function relationship; C C is the carbon content of the coal burned in the unit; Q is the calorific value per unit mass of coal in the coal-fired unit; is the molecular weight of carbon dioxide; Mr c is the molecular weight of carbon atoms.

[0031] Furthermore, in the calculation unit of carbon dioxide emissions of the coal-fired unit, the heat loss of boiler ash Q is not included in the heat loss of boiler hz And the heat loss Q of the boiler stone coal szm , the carbon dioxide emissions of coal-fired units are calculated using the following formula:

[0032]

[0033] Where Q tot Does not include Q hz and Q szm The total heat output of the boiler.

[0034] The beneficial effects of the present invention are as follows: the present invention avoids the chemical testing of the coal quality used during carbon emission monitoring, can simplify the coal quality testing in the process of obtaining the carbon dioxide emissions of the coal-fired unit, and makes the process of obtaining the carbon dioxide emissions of the coal-fired unit faster and more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without any creative work.

[0036] Figure 1 This is a flow chart of a method for obtaining carbon dioxide emissions from a coal-fired unit according to the present invention;

[0037] Figure 2 This is a composition diagram of a system for acquiring carbon dioxide emissions from a coal-fired unit according to the present invention. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0039] On the contrary, the present invention covers any alternatives, modifications, equivalents, and solutions that fall within the spirit and scope of the present invention as defined by the claims. Furthermore, to facilitate a better understanding of the present invention, certain specific details are described in detail below in the detailed description of the present invention. Those skilled in the art will be able to fully understand the present invention without these details.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention pertains. The terms used herein are for the purpose of describing specific embodiments only and are not intended to limit the present invention.

[0041] Example 1

[0042] The present invention provides a method for obtaining carbon dioxide emissions from a coal-fired unit, such as Figure 1 As shown, it includes: obtaining the effective output heat and loss heat of the boiler, and obtaining the total output heat Q of the boiler according to the effective output heat and loss heat total ;

[0043] The coal feeding amount of each coal feeder of the unit is obtained by measuring the device, and then the total coal feeding amount M of the coal-fired unit is calculated. coal ;

[0044] According to the total heat output of the boiler Q total and the total coal supply of coal-fired units M coal , calculate the estimated calorific value Q of unit mass coal coal , the formula is as follows:

[0045]

[0046] Among them, Q coal The unit is kJ / kg; Q total The unit is kJ / h; M coal The unit is kg / h.

[0047] Based on the historical coal quality test data of commonly used coal types in coal-fired units, a preset mathematical relationship between coal carbon content and calorific value C is established. C ~f(Q) database. The mathematical relationship between the carbon content and calorific value of the coal fired unit is expressed as: C C =f(Q),C C is the carbon content of the coal used in the unit, and Q is the calorific value of the coal per unit mass in the coal-fired unit.

[0048] It should be noted that the total heat output Q of the boiler can be calculated by referring to the Technical Guidelines for Real-time Online Monitoring of Thermal Efficiency of Power Plant Boilers (DL / T 2799-2024). total .

[0049] In a specific embodiment, the mathematical relationship between the carbon content and calorific value of the coal fired by the unit is simplified to C C ~f(Q) linear function relationship; the calorific value per unit mass of coal in the coal-fired unit is estimated to be Q coal As the Q value, the Cc value calculated using the linear function relationship is used as the estimated value of the carbon content of the coal entering the unit. At this time, the carbon dioxide emissions of the coal-fired unit are calculated using the following formula:

[0050]

[0051] Where, is the carbon dioxide emission of the coal-fired unit, in kg / h; η cor is the carbon oxidation rate of coal; Q total is the total heat output of the boiler; M coal is the total coal supply of the coal-fired unit; a is the linear fitting slope constant of the linear function relationship, in kg / kJ; b is the linear fitting intercept constant of the linear function relationship, dimensionless; is the molecular weight of carbon dioxide; Mr c is the molecular weight of carbon atoms.

[0052] In another specific embodiment, the heat loss of boiler ash and the heat loss of boiler pebble coal in the boiler heat loss are not taken into account, and the calorific value per unit mass of coal in the coal-fired unit is estimated as Q coal As the Q value, C calculated using the linear function relationship C The value is used as the estimated value of the carbon content of the coal fed into the unit, and the carbon dioxide emissions of the coal-fired unit are calculated using the following formula:

[0053]

[0054] Where Q tot Does not include Q hz and Q szm The total heat output of the boiler is in kJ / h; M coal is the total coal supply of the coal-fired unit; a is the linear fitting slope constant of the linear function relationship; b is the linear fitting intercept constant of the linear function relationship; is the molecular weight of carbon dioxide; Mr c is the molecular weight of carbon atoms; Q hz Q is the heat loss of boiler ash (mainly the chemical heat loss of carbon in ash, which may or may not include sensible heat loss); szmHeat loss from the pebble coal in the boiler (mainly chemical heat loss from the carbon content of the pebble coal, which may or may not include sensible heat loss).

[0055] It should be noted that the units marked after the physical quantities in the specification of the present invention are the units applicable in the formulas, but are not limited to these units. As long as the use of the formulas is met, overall adjustments can be made.

[0056] The present invention can obtain the carbon dioxide emissions of coal-fired units without conducting coal quality testing, and meets the requirements of real-time and accuracy, providing strong support for the calculation and monitoring of carbon dioxide emissions of the units.

[0057] Example 2

[0058] This embodiment is a system for obtaining carbon dioxide emissions from coal-fired units. Figure 2 As shown, the method for obtaining carbon dioxide emissions from a coal-fired unit described in Example 1 is implemented, and is composed of a calculation unit for estimating the calorific value per unit mass of coal for the unit, a unit for obtaining an estimated value of the carbon content of coal burned by the unit, and a unit for calculating carbon dioxide emissions from the coal-fired unit.

[0059] The unit unit mass coal calorific value calculation unit is used to calculate the calorific value per unit mass of coal of the coal-fired unit using the total heat output of the boiler and the total coal supply of the coal-fired unit.

[0060] The unit's coal carbon content estimated value acquisition unit is used to compare the estimated calorific value of the coal per unit mass of the coal-fired unit with the unit's coal carbon content-calorific value mathematical relationship preset in the database to obtain the estimated value of the unit's coal entering the furnace.

[0061] The carbon dioxide emission calculation unit of the coal-fired unit is used to calculate the carbon dioxide emission of the coal-fired unit based on the estimated carbon content of the coal entering the furnace of the unit.

[0062] It should be noted that each unit in the above-mentioned coal-fired unit carbon dioxide emission acquisition system can be implemented in whole or in part by software, hardware and a combination thereof. The above-mentioned units can be embedded in or independent of the processor in the computer device in the form of hardware, or can be stored in the memory of the computer device in the form of software, so that the processor can call and execute the operations corresponding to the above-mentioned units. For the specific definition of a coal-fired unit carbon dioxide emission acquisition system, please refer to the definition of a coal-fired unit carbon dioxide emission acquisition method (i.e., Example 1) above. The two have the same functions and effects and will not be repeated here.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the scope of protection of the claims of the present invention.

Claims

1. A method for obtaining carbon dioxide emissions from a coal-fired unit, characterized in that: include: Obtain the total heat output of the boiler and the total coal supply of the coal-fired unit, and calculate the estimated calorific value of the unit mass of coal in the coal-fired unit; Compare the estimated calorific value per unit mass of coal for the coal-fired unit with the preset mathematical relationship between carbon content and calorific value of the unit's coal in the database to obtain the estimated carbon content of the unit's incoming coal; The carbon dioxide emissions of the coal-fired unit are further calculated based on the estimated carbon content of the coal entering the unit.

2. The method for obtaining carbon dioxide emissions from a coal-fired unit according to claim 1, characterized in that: Obtain the effective heat output and heat loss of the boiler, and sum them to get the total heat output of the boiler; or divide the effective heat output of the boiler by the thermal efficiency of the boiler to get the total heat output of the boiler.

3. The method for obtaining carbon dioxide emissions from a coal-fired unit according to claim 1, characterized in that: The formula for calculating the calorific value per unit mass of coal in the coal-fired unit is: Where Q coal Q is the estimated calorific value of coal per unit mass in coal-fired units; total is the total heat output of the boiler; M coal It is the total coal supply of coal-fired units.

4. The method for obtaining carbon dioxide emissions from a coal-fired unit according to claim 1, characterized in that: Based on the historical coal quality test data of commonly used coal types in coal-fired units, a database of the mathematical relationship between the carbon content and calorific value of the coal used in the preset units is established. The mathematical relationship between the carbon content and calorific value of the coal used in the units is expressed as: C C =f(Q),C C is the carbon content of the coal used in the unit, and Q is the calorific value of the coal per unit mass in the coal-fired unit.

5. The method for obtaining carbon dioxide emissions from a coal-fired unit according to claim 4, characterized in that: The mathematical relationship between the carbon content and calorific value of the unit coal is simplified to C C ~f(Q) linear function relationship; the calorific value per unit mass of coal in the coal-fired unit is estimated to be Q coal As the Q value, C calculated using the linear function relationship C The value is used as the estimated value of the carbon content of the coal fed into the unit. At this time, the carbon dioxide emissions of the coal-fired unit are calculated using the following formula: Where, is the carbon dioxide emissions from coal-fired units; η cor is the carbon oxidation rate of coal; Q total is the total heat output of the boiler; M coal is the total coal supply of the coal-fired unit; a is the linear fitting slope constant of the linear function relationship; b is the linear fitting intercept constant of the linear function relationship; is the molecular weight of carbon dioxide; Mr c is the molecular weight of carbon atoms.

6. The method for obtaining carbon dioxide emissions from a coal-fired unit according to claim 5, characterized in that: The heat loss Q of boiler ash is not included in the heat loss of boiler hz And the heat loss Q of the boiler stone coal szm , the carbon dioxide emissions of coal-fired units are calculated using the following formula: Where Q tot Does not include Q hz and Q szm The total heat output of the boiler.

7. The method for obtaining carbon dioxide emissions from a coal-fired unit according to claim 1, characterized in that: The coal feeding amount of each coal feeder of the unit is obtained through the measuring device, and then the total coal feeding amount of the coal-fired unit is calculated.

8. A system for obtaining carbon dioxide emissions from a coal-fired unit, used to implement the method for obtaining carbon dioxide emissions from a coal-fired unit according to any one of claims 1 to 7, characterized in that: include: Unit unit coal calorific value calculation unit: used to calculate the calorific value of the unit coal by using the total heat output of the boiler and the total coal supply of the coal-fired unit; The unit's coal carbon content estimated value acquisition unit is used to compare the estimated calorific value of the coal per unit mass of the coal-fired unit with the unit's coal carbon content-calorific value mathematical relationship preset in the database to obtain the unit's furnace-input coal carbon content estimated value; Coal-fired unit carbon dioxide emissions calculation unit: used to calculate the coal-fired unit carbon dioxide emissions based on the estimated value of the carbon content of the coal entering the furnace of the unit.

9. A system for obtaining carbon dioxide emissions from a coal-fired unit according to claim 8, characterized in that: In the carbon dioxide emission calculation unit of the coal-fired unit, the mathematical relationship between the carbon content and calorific value of the coal fired unit is simplified to C C ~f(Q) linear function relationship; the calorific value per unit mass of coal in the coal-fired unit is estimated to be Q coal As the Q value, C calculated using the linear function relationship C The value is used as the estimated value of the carbon content of the coal fed into the unit. At this time, the carbon dioxide emissions of the coal-fired unit are calculated using the following formula: Where, is the carbon dioxide emissions from coal-fired units; η cor is the carbon oxidation rate of coal; Q total is the total heat output of the boiler; M coal is the total coal supply of the coal-fired unit; a is the fitting slope constant of the linear function relationship; b is the linear fitting intercept constant of the linear function relationship; C C is the carbon content of the coal burned in the unit, Q is the calorific value per unit mass of coal in the coal-fired unit; is the molecular weight of carbon dioxide; Mr c is the molecular weight of carbon atoms.

10. A system for obtaining carbon dioxide emissions from a coal-fired unit according to claim 9, characterized in that: Ignore the heat loss of boiler ash Q in the heat loss of boiler hz And the heat loss Q of the boiler stone coal szm , the carbon dioxide emissions of coal-fired units are calculated using the following formula: Where Q tot Does not include Q hz and Q szm The total heat output of the boiler.

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