A method for calculating carbon emission intensity of IGCC power plants

Abstract

The present invention belongs to the technical field of carbon emission calculation, and specifically relates to a method for calculating the carbon emission intensity of an IGCC power plant, including: defining the emission source of carbon emissions of the IGCC power plant; and determining the air flow and oxygen content corresponding to its oxygen source from the defined emission source; determining the excess air coefficient required for the emission source to fully react, using the excess air coefficient to correct the air flow, and obtaining the actual air flow; determining the correction coefficient based on interference factors; constructing a calculation model based on the actual air flow, oxygen content and correction coefficient, and calculating the carbon emissions of the emission source based on the calculation model. The calculation method provided by the present invention requires fewer detection values, is simple to operate, and can effectively improve the calculation efficiency of carbon emission data.

Description

Technical Field

[0001] The invention belongs to the technical field of carbon emission calculation, and in particular relates to a method for calculating the carbon emission intensity of an IGCC power plant. Background Art

[0002] Since the 1990s, the changes in the global climate system characterized by global warming have increasingly attracted widespread attention from the international community. The mainstream view of the international community is that global warming is the result of the increasing greenhouse effect caused by the increasing accumulation of greenhouse gases emitted by humans since the industrial revolution. After research, it was found that among the six greenhouse gases (CO 2 , CH 4 、N 2 O, HFCs, PFCs, SF 6 ), CO 2 The carbon emissions account for more than 50% of the global temperature rise, and the power generation industry is one of the main sources of carbon emissions.

[0003] IGCC (Integrated Gasification Combined Cycle) integrated coal gasification combined cycle power generation system is an advanced power system that combines coal gasification technology with efficient combined cycle. It consists of two major parts, namely the coal gasification and purification part and the gas-steam combined cycle power generation part. Compared with traditional coal-fired power generation technology, IGCC integrates coal gasification and gas-steam combined cycle power generation technology with advantages such as high power generation efficiency and low pollutant emissions. It is currently the most internationally verified, industrialized, and most promising clean, efficient, and low-carbon coal-fired power generation technology.

[0004] In order to more conveniently realize the statistics of carbon emissions from power plants, a convenient and fast method for calculating carbon emissions is needed.

[0005] Chinese patent number CN106442852A discloses a method for calculating carbon dioxide emissions from a coal-fired power plant from an output end, the method comprising the following steps: S1. obtaining the volume fraction of carbon dioxide in the flue gas emitted from a coal-fired boiler of a coal-fired power plant, S2. detecting the exhaust gas temperature of the coal-fired boiler, S3. using the formula according to the volume fraction of carbon dioxide in the flue gas emitted by the coal-fired boiler and the exhaust gas temperature of the coal-fired boiler Calculate the carbon dioxide emissions per unit of electricity generated by the generator set, where Indicates carbon dioxide emissions t / m3; T py Indicates exhaust gas temperature, °C; It represents the volume fraction of carbon dioxide in flue gas, %. This method can also be applied to IGCC power plants.

[0006] The invention patent of China Publication No. CN106650068A discloses a calculation method for predicting carbon emissions of power plants, which includes the following steps: S1. Establishing a mathematical model to obtain a relationship of the fuel characteristic coefficient β, S2. Calculating the value of the fuel characteristic coefficient β of the coal burned in the power plant, S3. Calculating the percentage content of carbon dioxide in the flue gas, S4. Calculating the total amount of flue gas emissions, S5. Calculating the total amount of carbon dioxide emissions, this invention uses MATLAB software to perform multivariate stepwise linear regression to fit the linear equation of the fuel characteristic coefficient β and calculates the carbon dioxide emissions based on the oxygen and sulfur dioxide concentrations detected in the flue gas. This method can also be applied to IGCC power plants to calculate carbon emissions.

[0007] The existing methods for calculating carbon emissions during the operation of IGCC power plants have the following problems: (1) During the calculation process, a large number of values ​​need to be detected, and the content of a certain component needs to be detected, which requires the installation of a large number of measuring instruments. The process is relatively complicated and the cost is relatively high. (2) Some calculation processes use fitting, which requires a large amount of data to support and takes a long time. In addition, the fitting results can only be used for the calculation of a certain type of coal, and the universality of the fitting results cannot be guaranteed.

[0008] Therefore, for IGCC power plants, it is urgent to design a calculation method to solve the above problems. Summary of the invention

[0009] In order to overcome the defects of the prior art mentioned above, the technical problem to be solved by the present invention is to propose a method for calculating the carbon emission intensity of an IGCC power plant with a small number of detection values ​​and simple calculation.

[0010] In order to solve the above technical problems, the technical solution adopted by the present invention is: a method for calculating the carbon emission intensity of an IGCC power plant, comprising:

[0011] Define the sources of carbon emissions from IGCC power plants;

[0012] The air flow rate and oxygen content corresponding to the oxygen source of the emission source defined are determined;

[0013] Determining an excess air coefficient required for the emission source to fully react, correcting the air flow rate using the excess air coefficient, and obtaining an actual air flow rate;

[0014] Determine correction factors based on interference factors;

[0015] A calculation model is constructed based on the actual air flow, oxygen content and correction coefficient, and the carbon emissions of the emission source are calculated based on the calculation model.

[0016] The beneficial effects of the present invention are:

[0017] 1) The calculation process of the carbon emission intensity of the IGCC power plant provided by the present invention is simple. It only needs to measure the air flow rate and calculate the excess air coefficient in the IGCC power plant to use this model to calculate the carbon emission of the IGCC power plant. The measurement data is relatively small, which can effectively save the manpower, material resources and time costs required for measuring the data, and is convenient and fast;

[0018] 2) The method for calculating the carbon emission intensity of an IGCC power plant provided by the present invention can calculate the carbon emissions of IGCC power plants with different parameters, and has no special requirements on the type of coal used in the operation of the power plant. It can be used for the calculation process of units with different parameters and different types of coal, and there is no need to provide separate calculation models for different units, and has strong versatility;

[0019] 3) At the same time, the method for calculating the carbon emission intensity of an IGCC power plant provided by the present invention uses the amount of air consumed by the power plant to indirectly calculate the carbon emissions during the operation of the IGCC power plant, avoiding the detection of raw materials and gas production, reducing the difficulty of detecting related data, and making the calculation process simpler. DETAILED DESCRIPTION

[0020] In order to explain the technical content, achieved objectives and effects of the present invention in detail, the following is an explanation in conjunction with the implementation modes.

[0021] A method for calculating the carbon emission intensity of an IGCC power plant includes:

[0022] Define the sources of carbon emissions from IGCC power plants;

[0023] The air flow rate and oxygen content corresponding to the oxygen source of the emission source defined are determined;

[0024] Determining an excess air coefficient required for the emission source to fully react, correcting the air flow rate using the excess air coefficient, and obtaining an actual air flow rate;

[0025] Determine correction factors based on interference factors;

[0026] A calculation model is constructed based on the actual air flow, oxygen content and correction coefficient, and the carbon emissions of the emission source are calculated based on the calculation model.

[0027] Among them, the emission source is defined as the carbon emission generated by the chemical reaction of coal in the system, that is, it is necessary to exclude other emission sources related to non-coal chemical reactions from the total carbon emissions when determining the carbon emissions of IGCC power plants. The other emission sources mainly include carbon emissions generated by externally purchased electricity, externally purchased heat, personnel activities, unit operation and other processes. Although coal chemical reactions and other emission sources should be included in the calculation of IGCC power plant carbon emissions, since carbon dioxide emissions generated by coal chemical reactions are the main source of carbon emissions, and carbon dioxide emissions from other emission sources account for a small proportion, only carbon dioxide generated by coal chemical reactions is calculated in the calculation method of carbon emission intensity of IGCC power plants provided by the present invention.

[0028] Specifically, the calculation method of the carbon emission intensity of the IGCC power plant provided by the present invention is to derive the formula according to the following steps:

[0029] S1. Define the coal chemical reaction as the emission source in the carbon emissions of IGCC power plants, and determine the main process of this emission source as:

[0030] C+H 2 O→CO+H 2

[0031] 2H 2 +O 2 →2H 2 O

[0032] 2CO+O 2 →2CO 2

[0033] From the reaction equation, it can be seen that the molar amount of oxygen consumed is the same as the molar amount of carbon dioxide generated, so formula (1) can be derived:

[0034]

[0035] in, It is the amount of carbon dioxide generated during the operation of the system, in t / h; It is the amount of oxygen required during the operation of the system, in t / h; is the molar mass of carbon dioxide, in g / mol; is the molar mass of oxygen in g / mol.

[0036] S2. The source of oxygen consumption in formula (1) is the air introduced into the system by the compressor, and the air introduced into the system by the compressor is mainly consumed by the coal gasifier and the gas turbine combustion chamber, that is, the air introduced into the system by the compressor is determined by the amount of air consumed by the coal gasifier and the amount of air consumed by the gas turbine combustion chamber. Therefore, formula (2) can be derived:

[0037]

[0038] Among them, m air，1 is the amount of air consumed by the gasifier, in t / h; m air，2 is the amount of air consumed by the gas turbine combustion chamber, in t / h; It is the oxygen content in the air, dimensionless, and is generally taken as 0.23117.

[0039] S3. During the operation of the system, in order to ensure sufficient reaction, the system usually needs to introduce more air, so formula (3) can be derived:

[0040]

[0041] Among them, α is the excess air coefficient, dimensionless;

[0042] S4. The excess air coefficient α depends on the carbon-oxygen ratio of the water-gas reaction and the carbon-oxygen ratio of the air in the combustion chamber of the gas turbine during the operation of the power plant. That is, the excess air coefficient is determined by the oxygen-carbon ratio of the water-gas reaction and the oxygen-carbon ratio of the air in the combustion chamber of the gas turbine. Therefore, formula (4) can be derived:

[0043]

[0044] Among them, ROCN is the carbon-oxygen ratio in the water-gas reaction process, dimensionless; ALAMN is the carbon-oxygen ratio in the air in the gas turbine combustion chamber, dimensionless.

[0045] S5. There are usually some interfering factors in the process of calculating the carbon emissions of the system, such as air leakage during operation and / or a certain consumption of oxygen by hydrogen in the air. However, since the content of hydrogen in coal is relatively low and the proportion of hydrogen in different types of coal is roughly the same, and the impact of air leakage on the calculation is also relatively weak, the formula can be corrected by a correction coefficient. The correction coefficient is usually a constant, and in the present invention, it is taken as 0.9, and formula (5) can be obtained:

[0046]

[0047] Among them, the air flow, the carbon-oxygen ratio of the water-gas reaction, the carbon-oxygen ratio of the air in the gas turbine combustion chamber, and the oxygen content in the air can all be obtained through power plant monitoring and calculation. Therefore, after obtaining and sorting these data, the sorted data are substituted into formula (5) to calculate the carbon emission data of the IGCC power plant.

[0048] Although in the formula, if the correction coefficient is taken as 0.9 and the oxygen content is taken as 0.23117, there will be a certain error in the result, the error is still within an acceptable range (the allowable error range for calculating carbon dioxide emissions from the energy sector required by the IPCC guidelines is ±5%). Therefore, the carbon emission data calculated by the calculation method of the carbon emission intensity of the IGCC power plant provided by the present invention is of reference significance.

[0049] Example 1

[0050] A method for calculating the carbon emission intensity of an IGCC power plant is used. The carbon emission calculation of a 265MW IGCC power plant during a variable load process is taken as an example. The carbon emission calculation is performed according to the above formula (5), where the ROCN value is 1.1 and the ALAMN value is 3. The results are shown in Table 1.

[0051] Table 1

[0052]

[0053] Comparative Example 1

[0054] A technical method for calculating the carbon emission intensity of an IGCC cell, with the same test object as in Example 1 (a 265MW IGCC power plant load variation process), and a specific calculation method as that disclosed in Chinese Patent No. CN106442852A. The results are shown in Table 2.

[0055] Table 2

[0056]

[0057] In Tables 1 and 2, the actual carbon emissions are calculated by detailed modeling of the units using EBSILON professional software.

[0058] By comparing the data in Table 1 and Table 2, it can be seen that compared with the existing calculation method, the present invention uses less data, is easier to obtain, and has a simple calculation process. Although the relative error is slightly larger than that of other methods, it is still within the range of ±5%, which is acceptable in the engineering calculation process.

[0059] In summary, the calculation process of the carbon emission intensity of the IGCC power plant provided by the present invention is simple. It only needs to measure the air flow rate and calculate the excess air coefficient in the IGCC power plant to use this model to calculate the carbon emissions of the IGCC power plant. There are fewer measurement data, which can effectively save the manpower, material resources and time costs required for measuring data, and is convenient and fast; the calculation method of the carbon emission intensity of the IGCC power plant provided by the present invention can calculate the carbon emissions of IGCC power plants with different parameters, and has no special requirements for the types of coal used in the operation of the power plant. It can be used for the calculation process of units with different parameters and different types of coal, and there is no need to provide separate calculation models for different units. It has strong versatility; at the same time, the calculation method of the carbon emission intensity of the IGCC power plant provided by the present invention uses the amount of air consumed by the power plant to indirectly calculate the carbon emissions during the operation of the IGCC power plant, avoiding the detection of raw materials and gas production, reducing the difficulty of detecting related data, and making the calculation process simpler.

[0060] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent transformations made using the contents of the present invention specification, or directly or indirectly applied in related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for calculating carbon emission intensity of an IGCC power plant, characterized in that: include: Define the sources of carbon emissions from IGCC power plants; The air flow rate and oxygen content corresponding to the oxygen source of the emission source defined are determined; Determining an excess air coefficient required for the emission source to fully react, correcting the air flow rate using the excess air coefficient, and obtaining an actual air flow rate; Determine correction factors based on interference factors; Building a calculation model based on actual air flow, oxygen content and correction coefficient, and calculating the carbon emissions of the emission source based on the calculation model; According to the emission source defined, the amount of air consumed by the coal gasifier m is obtained. air，1 , the amount of air consumed by the gas turbine combustion chamber m air，2 , the oxygen content in the air The oxygen-carbon ratio ROCN of the water-gas reaction process and the carbon-oxygen ratio ALAMN of the air in the gas turbine combustion chamber; The carbon emissions generated by the system are calculated as follows in, is the molar mass of carbon dioxide, is the molar mass of oxygen.

2. The calculation method according to claim 1, characterized in that: The emission sources are defined as carbon emissions generated by chemical reactions of coal in the system.

3. The calculation method according to claim 1, characterized in that: The source of oxygen is air introduced into the system by a compressor.

4. The calculation method according to claim 3, characterized in that: The air introduced into the system by the compressor is determined by the amount of air consumed by the coal gasifier and the amount of air consumed by the gas turbine combustion chamber.

5. The calculation method according to claim 1, characterized in that: The excess air ratio is determined by the oxygen-carbon ratio of the water-gas reaction and the oxygen-carbon ratio of the air in the gas turbine combustion chamber.

6. The calculation method according to claim 1, characterized in that: The interfering factors are system leakage and / or consumption of oxygen by hydrogen in the system air.

7. The calculation method according to claim 1, characterized in that: The oxygen content is 0.23117.

8. The calculation method according to claim 1, characterized in that: The correction coefficient is set to 0.9.

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