A Carbon Footprint Accounting Method for High Sulfur Gas Field Products

Abstract

The present invention relates to a carbon footprint accounting method for high-sulfur gas field products, belonging to the technical field of product carbon footprint. This method conducts a series of analyses on high-sulfur gas field products. First, according to the carbon footprint accounting boundary, the involved production processes are divided into different carbon footprint units. Then, the actual existing carbon emission types in each carbon footprint unit are analyzed, including energy emissions and process emissions. According to different carbon emission types, corresponding carbon emission calculation models are designed to obtain the total sum of process emissions generated by producing the products and the total sum of emissions generated by the energy consumed in producing the products. Finally, the calculated amounts obtained from each model are added together to obtain the total carbon emissions of the products, realizing the scientific accounting of the carbon footprint of high-sulfur gas field products, filling the gap in the carbon footprint accounting method for high-sulfur gas field products, and having high application value.

Description

Technical Field

[0001] The present invention belongs to the technical field of product carbon footprint, and particularly relates to a method for calculating the carbon footprint of products in high-sulfur gas fields. Background Art

[0002] At present, green and low-carbon is an important direction for economic and social development, and it is crucial to calculate the carbon footprint of products. The carbon footprint is defined as the measurement of the direct and indirect greenhouse gas emissions caused by a certain product or activity during its life cycle, with the mass equivalent of carbon dioxide as the unit. By calculating the carbon footprint of products, understanding the sources, distributions, and footprints of carbon emissions of enterprise products, factors affecting carbon emissions can be analyzed, and the space, direction, and specific measures for carbon reduction can be clarified to promote the green and low-carbon production of enterprises.

[0003] Commonly used carbon footprint calculation methods include the life cycle assessment method and the input-output method. The data that needs to be collected and analyzed includes activity data and emission factors, which generally come from statistics, input-output tables, or on-site investigation and testing. For example, some domestic research institutions and enterprises have carried out research on the following product carbon footprints and their calculation methods:

[0004] (1) Life cycle assessment method:

[0005] The Chinese invention patent with the publication number CN107451387A proposes "a method for measuring the carbon footprint of petrochemical products". This method is for petrochemical products produced from crude oil as raw materials, including: obtaining the whole life cycle process of the carbon footprint of petrochemical products to obtain a carbon footprint model of petrochemical products; establishing a carbon footprint measurement model based on the whole life cycle process, petrochemical product production process, and greenhouse gas emissions of unit devices; obtaining the numerical values and quantities of the parameters required in the carbon footprint measurement model and calculating the carbon emissions of the whole life cycle of petrochemical products.

[0006] (2) Input-output method:

[0007] The Chinese invention patent with the publication number CN111253967A proposes "a method for allocating co-products in the carbon footprint evaluation of atmospheric and vacuum distillation units". This method is for atmospheric and vacuum distillation units, that is, some specific production links of products, including: calculating the CO2 emissions according to the fuel consumption of the heating furnace; calculating the heat absorbed by each fraction from the heating furnace according to the enthalpy values of each fraction at the inlet and outlet of the heating furnace; and allocating the CO2 emissions to each fraction according to the proportion of the heat absorbed by each fraction from the heating furnace.

[0008] However, high-sulfur gas fields use sulfur-containing natural gas in the subsurface as raw materials to produce commercial natural gas through production processes such as gas production, gathering and transportation, and purification. Since the sulfur content in the raw material natural gas is relatively high, sulfur products are also produced simultaneously. For the carbon footprint accounting of high-sulfur gas field products, although the above-mentioned publicly disclosed invention patents or patent applications can be referred to in some aspects, due to the significant differences between the production process of high-sulfur gas fields and the production process of petrochemical products using crude oil as raw materials, and because the sulfur components contained in the raw material gas must be recovered and treated, its process is more complex than that of general sulfur-free or low-sulfur gas fields, and it involves the carbon emission division of co-produced products. Therefore, the carbon footprint accounting method for high-sulfur gas field products is still blank, and the existing methods are not applicable to the carbon footprint accounting of high-sulfur gas field products. Summary of the Invention

[0009] The object of the present invention is to provide a carbon footprint accounting method for high-sulfur gas field products, which is used to solve the problem that the existing methods are not applicable to the carbon footprint accounting of high-sulfur gas field products.

[0010] Based on the above object, the technical solution of a carbon footprint accounting method for high-sulfur gas field products is as follows:

[0011] 1) Determine the carbon footprint accounting boundary of high-sulfur gas field products, including: from the wellhead of the gas well to the product leaving the factory, and the product is sulfur or natural gas;

[0012] 2) Divide the carbon footprint units according to the production processes involved in the carbon footprint accounting boundary, and determine one or more carbon emission types existing in each carbon footprint unit. The carbon emission types at least include energy emissions and process emissions;

[0013] 3) For the carbon footprint units with the carbon emission type of process emissions, determine the proportion of the process emissions generated by each carbon footprint unit in producing the product in the total process emissions of this unit, multiply this proportion by the process emissions of this unit, and obtain the process emissions generated by this unit in producing the product. Add up the process emissions generated by each unit in producing the product to obtain the total sum of process emissions generated by producing the product;

[0014] For the carbon footprint units with the carbon emission type of energy emissions, determine the emissions generated by the energy consumed by each production unit in each carbon footprint unit in producing the product, which is the total energy emissions of each production unit multiplied by the proportion of the energy emissions consumed by each production unit in producing the product in the total energy emissions of this unit; then add up the emissions generated by the energy consumed by each production unit in each carbon footprint unit in producing the product to obtain the total sum of emissions generated by the energy consumed in producing the product; the production unit is the equipment that generates energy emissions in the carbon footprint unit.

[0015] 4) Sum up the total emissions calculated for each type of carbon emission to obtain the carbon emissions of producing the product.

[0016] The beneficial effects of the above technical solution are:

[0017] Through a series of analyses of high-sulfur gas field products, the present invention first divides the involved production processes into different carbon footprint units according to the carbon footprint accounting boundary, and then analyzes the actual existing carbon emission types in each carbon footprint unit, including energy emissions and process emissions. According to different carbon emission types, corresponding carbon emission calculation models are designed to obtain the total process emissions generated by producing the product and the total emissions generated by the energy consumed in producing the product. Finally, the calculated amounts obtained from each model are added up to obtain the total carbon emissions of the product, realizing the scientific accounting of the carbon footprint of high-sulfur gas field products, filling the gap in the carbon footprint accounting of high-sulfur gas field products, and having high application value.

[0018] Further, in order to improve the accuracy of carbon footprint accounting, in step 3), for the carbon footprint units with carbon emission type of energy emission, it also includes determining the public works carbon emissions of each carbon footprint unit; the calculation formula for obtaining the carbon emissions of producing the product in step 4) is as follows:

[0019]

[0020] In the formula, E GHG_S is the carbon emissions of the product, E GHG_制程 is the process emissions of each carbon footprint unit with carbon emission type of process emission, E GHG_生产 is the energy emissions of each production unit in the carbon footprint unit with carbon emission type of energy emission, E GHG_公辅 is the public works carbon emissions of each carbon footprint unit, n 制程_S is the proportion of the process emissions generated by each carbon footprint unit in producing the product to the total process emissions of this unit, n U_S is the proportion of the energy emissions consumed by each production unit in producing the product to the total energy emissions of this unit, C 公辅_S is the contribution rate of the carbon emissions generated by public works to each production unit.

[0021] Among them, the calculation formula for the public works carbon emissions of each carbon footprint unit is:

[0022]

[0023] In the formula, E GHG_U_公辅 is the public works carbon emissions of each carbon footprint unit, E GHG_公辅 is the total public works carbon emissions, P 工质_U is the consumption of energy-consuming working medium of each carbon footprint unit, P 工质is the output of energy-consuming working medium for utilities.

[0024] Further, when the product is sulfur and the carbon footprint unit is the gathering and transportation unit or the desulfurization unit, the calculation formula for the proportion of the process emissions generated by each carbon footprint unit in producing the product to the total process emissions of this unit is as follows:

[0025]

[0026] In the formula, n 制程_S_集输δ脱硫 is the proportion of the process emissions generated by the gathering and transportation unit or the desulfurization unit in producing the product to the total process emissions of this unit, is the proportion of H2S in the raw gas, is the proportion of CO2 in the raw gas, is the proportion of CH4 in the raw gas;

[0027] The calculation formula for the process emissions of the gathering and transportation or desulfurization unit is:

[0028] E GHG_S_集输δ脱硫制程 = E GHG_集输δ脱硫制程 ×n 制程_S_集输δ脱硫

[0029] In the formula, E GHG_S_集输δ脱硫制程 is the process emissions generated by the gathering and transportation or desulfurization unit in producing sulfur products, and E GHG_集输δ脱硫制程 is the process emissions of the gathering and transportation or desulfurization unit.

[0030] Further, when the product is sulfur and the carbon footprint unit is the sulfur recovery unit, the calculation formula for the proportion of the process emissions generated by each carbon footprint unit in producing the product to the total process emissions of this unit is as follows:

[0031]

[0032] In the formula, n 制程_S_硫磺回收 is the proportion of the process emissions generated by the sulfur recovery unit in producing the product to the total process emissions of this unit, is the proportion of H2S in the raw gas, is the proportion of CO2 in the raw gas, is the proportion of CH4 in the raw gas, is the CO2 content in the natural gas product;

[0033] The calculation formula for the process emissions of the sulfur recovery unit is:

[0034] E GHG_S_硫磺回收制程 = E GHG_硫磺回收制程 ×n 制程_S_硫磺回收

[0035] In the formula, E GHG_S_硫磺回收制程E is the process emissions generated from the production of sulfur products in the sulfur recovery unit. GHG_硫磺回收制程 E is the process emissions of the sulfur recovery unit.

[0036] Furthermore, when the product is sulfur, the method for determining the proportion of the energy emissions consumed by each production unit in producing the product in the total energy emissions of this unit is as follows:

[0037] When the carbon footprint unit is the gathering and transportation unit, the calculation formula for the proportion is as follows:

[0038]

[0039] In the formula, n U_S is the proportion of the energy emissions consumed by each production unit in producing the product in the total energy emissions of this unit, is the proportion of H2S in the raw gas, is the proportion of CO2 in the raw gas, is the proportion of CH4 in the raw gas;

[0040] When the carbon footprint unit is the desulfurization unit or the tail gas treatment unit, the calculation formula for the proportion is as follows:

[0041]

[0042] In the formula, is the CO2 content in the natural gas product;

[0043] When the carbon footprint unit is the dehydration unit, the proportion is zero; when the carbon footprint unit is the sulfur recovery unit, the sour water stripping unit, or the sulfur storage and transportation unit, the proportion is 100%.

[0044] Furthermore, the calculation formula for the emissions generated by the energy consumed by each production unit in producing the product in each carbon footprint unit is as follows:

[0045] E GHG_S_U = E GHG_U × n U_S

[0046] E GHG_S_U is the energy emissions consumed by each production unit in producing sulfur in each carbon footprint unit, and E GHG_U is the total energy emissions of each production unit in each carbon footprint unit. Description of the Drawings

[0047] Figure 1 is a schematic diagram of the carbon footprint accounting process for products in a high-sulfur gas field in an embodiment of the present invention;

[0048] Figure 2 is a schematic diagram of the division of carbon footprint units in an embodiment of the present invention;

[0049] Figure 3 It is the emission type diagram of the carbon footprint unit in the embodiment of the present invention;

[0050] Figure 4 It is the schematic diagram of the carbon footprint chain of sulfur products in the embodiment of the present invention. Specific embodiments

[0051] The following further describes the specific embodiments of the present invention with reference to the accompanying drawings.

[0052] This embodiment proposes a method for calculating the carbon footprint of high-sulfur gas field products. The following combines Figure 1 , taking the specific implementation process of a certain gas field as an example, and describes the method process of the present invention in detail as follows:

[0053] Step 1: Determine the carbon footprint accounting boundary.

[0054] The most commonly used carbon footprint accounting boundaries are the following two:

[0055] One is the product carbon footprint evaluation covering the entire life cycle stage (from cradle to grave). The evaluation stage can be briefly described as raw material - manufacturing - distribution - consumption - treatment / recycling, that is, the evaluation content includes raw material acquisition, product manufacturing, distribution and retail, consumer use, and the entire life cycle of final treatment and recycling.

[0056] The other is the product carbon footprint evaluation from raw material acquisition to the product leaving the production organization (from cradle to gate). The evaluation stage can be briefly described as raw material - manufacturing, that is, the evaluation content includes raw material acquisition and product manufacturing stages. For specific enterprises, the life cycle stage from cradle to grave has too large a coverage boundary, involving different enterprises such as product use and recycling, and it is difficult to obtain data, and the accuracy of the accounting results is relatively low. Therefore, the carbon footprint accounting boundary of enterprise products is generally set as the product stage of "from cradle to gate".

[0057] In this embodiment, specifically for high-sulfur gas fields, the carbon footprint accounting boundary of products can generally be set from the wellhead of the gas well to the product gas and by-product sulfur leaving the factory.

[0058] Step 2: Divide the carbon footprint units.

[0059] The three main components of the produced gas in high-sulfur gas fields are CH4, H2S, and CO2. Among them, for the two products of natural gas and sulfur, except for a small amount of CO2 entering the natural gas product, all other CO2 is discharged. In this embodiment, using the analysis method based on the production process, the entire production process of sulfur from raw material to product is divided into 4 carbon footprint systems (gas production and transportation, purification, auxiliary, and service), and 10 carbon footprint units (gas production, gas gathering and transportation, desulfurization, dehydration, sulfur recovery, tail gas treatment, sour water stripping, sulfur storage and transportation, utilities, office and living), as shown in the appendix Figure 2 as shown.

[0060] Step 3: Determine the carbon emission types of each carbon footprint unit.

[0061] Specifically, the carbon emission types of high-sulfur gas fields can be divided into: stationary source emissions, mobile source emissions, indirect emissions, process emissions, and fugitive emissions. Among them, stationary source emissions, mobile source emissions, and indirect emissions are mainly carbon emissions generated by energy consumption (i.e., energy emissions), and the energy includes natural gas, electricity, diesel, gasoline, etc. Process emissions are carbon emissions generated by gas venting in the process; fugitive emissions are mainly carbon emissions generated by air conditioners, refrigerators, sewage treatment, septic tanks, fire extinguishers, etc., and the emission volume is relatively small.

[0062] In this embodiment, different carbon emission units (i.e., carbon footprint units) involve different emission types. Analyze the emission types corresponding to each emission unit to determine the carbon emission framework of each carbon emission unit. As shown in the appendix Figure 3 as shown. Combining the carbon emission situation in the production process, the emission types of high-sulfur gas fields can be summarized into three categories: process emissions, fugitive emissions, and emissions generated by energy consumption (i.e., energy emissions). Each unit may involve zero, one, two, or multiple carbon emission types. For example, the gas production unit (i.e., the carbon footprint unit of gas production) has no emissions, the dehydration unit, tail gas treatment unit, sour water stripping unit, utilities unit, and storage and transportation unit all involve one carbon emission type, the desulfurization unit, sulfur recovery unit, and office and living unit all involve two carbon emission types, and the gas gathering and transportation unit involves three carbon emission types.

[0063] Step 4: Establish a carbon footprint accounting model for sulfur products.

[0064] Since high-sulfur gas fields have two co-produced products, natural gas and sulfur, calculating the carbon footprint of one product, the carbon footprint of the other product can be calculated through the total carbon amount. Therefore, the present invention gives the carbon footprint accounting model for sulfur products as follows:

[0065]

[0066] In the formula:

[0067] U is the first letter of UNIT, representing the production unit;

[0068] E GHG_S — Sulfur product carbon emissions, in tCO2 equivalent;

[0069] E GHG_制程 、E GHG_生产 、E GHG_公辅 、E GHG_附属 — Total carbon emissions from the process, production unit, utilities, and auxiliary systems respectively, in tCO2 equivalent;

[0070] n 制程_S — Proportion of process emissions from sulfur production in the total process emissions, %;

[0071] n U_S — Proportion of emissions from energy consumed in sulfur production in each production unit in the total energy emissions, %;

[0072] C 公辅_S — Contribution rate of carbon emissions from utilities to each production unit, %, and the contribution rate is determined according to formula (10).

[0073] According to the above formula, it can be seen that the carbon footprint accounting model includes: a process emission proportion model, an energy consumption emission proportion model, and a utilities proportion model. The process emission proportion model is used to determine the total process emissions generated by the carbon footprint unit due to sulfur production, the energy consumption emission proportion model is used to determine the total energy emissions consumed by the carbon footprint unit due to sulfur production, and the utilities proportion model is used to determine the total utilities carbon emissions of the carbon footprint unit. The sum of the emissions calculated by these three models is added to obtain the total emissions generated by sulfur production.

[0074] Specifically, a set of processes and equipment in a high-sulfur gas field produce two products, natural gas and sulfur. According to the IOA method (input-output method), the relationship between the raw material components and products (sulfur or natural gas) in each production unit is analyzed to determine the relevant proportion models for sulfur or natural gas. Taking the relevant proportion model of sulfur as an example, the specific calculation processes of each model are described below:

[0075] (1) Process emission proportion model:

[0076] This model is: determine the proportion of process emissions generated by each carbon emission unit due to sulfur production in the total process emissions of this unit, multiply this proportion by the process emissions of this unit to obtain the process emissions generated by this unit for sulfur production, and add up the process emissions of each unit to obtain the total process emissions generated by the carbon footprint unit due to sulfur production.

[0077] The proportion of sulfur in the process emissions is analyzed by IOA. The main components of the raw gas in high-sulfur gas fields are CH4, H2S, and CO2. The CH4 in the raw gas composition produces natural gas, and the carbon emissions generated belong to the natural gas product; the H2S produces sulfur, and the carbon emissions generated belong to the sulfur product; CO2, as a common impurity in natural gas and sulfur products, the carbon emissions generated are accounted for according to the proportions of CH4 and H2S in the raw gas.

[0078] The carbon emissions are split according to the functional purposes of the emission facilities in each emission unit. The carbon emissions generated by facilities purely set for sulfur products belong to sulfur products; the carbon emissions generated by facilities set for natural gas products belong to natural gas products.

[0079] According to Figure 3 As shown, the process emissions are distributed in the gathering and transportation unit, the desulfurization unit, and the sulfur recovery unit. For the gathering and transportation unit and the desulfurization unit, the gas discharged during the process is the raw gas, and the accounting model for the process emissions is:

[0080] E GHG_S_集输δ脱硫制程 =E GHG_集输δ脱硫制程 ×n 制程_S_集输δ脱硫 (2)

[0081] In the formula:

[0082] E GHG_S_集输δ脱硫制程 —The process emissions generated by the gathering and transportation or desulfurization unit in producing sulfur products, in units of tCO2 equivalent;

[0083] E GHG_集输δ脱硫制程 —The process emissions of the gathering and transportation or desulfurization unit, in units of tCO2 equivalent;

[0084] n 制程_S_集输δ脱硫 —The proportion of the process emissions generated by the gathering and transportation or desulfurization unit in producing sulfur in the total process emissions of this unit. The calculation formula is as follows:

[0085]

[0086] In the formula:

[0087] —The proportion of H2S in the raw gas, %;

[0088] —The proportion of CO2 in the raw gas, %;

[0089] —The proportion of CH4 in the raw gas, %;

[0090] For the sulfur recovery unit, the process emissions are the direct emissions of CO2 in the tail gas into the atmosphere. At this time, part of the CO2 in the raw gas enters the product. Therefore, the accounting model for the process emissions of the sulfur recovery unit is:

[0091] E GHG_S_硫磺回收制程 = E GHG_硫磺回收制程 × n 制程_S_硫磺回收 (4)

[0092] In the formula:

[0093] E GHG_S_硫磺回收制程 — Process emissions generated by the sulfur recovery unit in producing sulfur products, in tCO2 equivalent;

[0094] E GHG_硫磺回收制程 — Process emissions of the sulfur recovery unit, in tCO2 equivalent;

[0095] n 制程_S_硫磺回收 — The proportion of process emissions generated by the sulfur recovery unit in producing sulfur in the total process emissions of this unit. The calculation formula is as follows:

[0096]

[0097] In the formula:

[0098] — CO2 content in natural gas products, %.

[0099] (2) Energy consumption emission ratio model:

[0100] This model is: Determine the emissions generated by the energy consumed in producing sulfur in each production unit, which is the product of the energy emissions of each unit and the proportion of sulfur; then add up the emissions generated by the energy consumed in producing sulfur in each production unit to obtain the total emissions generated by the energy consumed in producing sulfur. The production units mentioned here refer to the equipment that generates energy emissions in the carbon footprint unit, such as hydrogenation furnaces, tail gas incinerators, etc.

[0101] Among them, the accounting model for the emissions generated by the energy consumed in producing sulfur in each production unit is:

[0102] E GHG_S_U = E GHG_U × n U_S (6)

[0103] In the formula:

[0104] E GHG_S_U — Emissions of energy consumed in producing sulfur in each production unit, in tCO2 equivalent;

[0105] E GHG_U — Total energy emissions of each production unit, in tCO2 equivalent;

[0106] n U_S—The proportion of the energy emissions consumed in sulfur production in each production unit to the total energy emissions of this unit, %. Due to the different compositions and operations of each production unit, the calculation methods of n for each production unit are also different, which are divided into the following situations: U_S The calculation methods are also different, which are divided into the following situations:

[0107] 1) The accounting model of n for the gathering and transportation unit: U_S The accounting model of n for the gathering and transportation unit:

[0108] The purpose of the gathering and transportation unit is to transport the high-sulfur raw gas produced by the gas well. The energy emissions generated during this process are: the emissions generated by the consumption of natural gas in the heating furnace, and the emissions generated by the consumption of energy such as electricity, gasoline, and diesel.

[0109] The heating furnace is used to heat the raw gas to a certain temperature through natural gas. The flow rate of the raw gas is basically proportional to the consumption of natural gas in the heating furnace, that is, the more raw gas to be heated, the more natural gas is consumed, and the more carbon emissions are generated. The emissions generated by the consumption of energy such as electricity, gasoline, and diesel are generated during the transportation process of the raw gas and are divided according to the carbon emission division principle of the raw gas. Therefore, the accounting model of n is as follows: U_S The accounting model of n is as follows:

[0110]

[0111] 2) The accounting model of n for the desulfurization unit: U_S The accounting model of n for the desulfurization unit:

[0112]

[0113] In the above formula, because a part of CO2 enters the natural gas product, only the remaining CO2 is split proportionally.

[0114] 3) The accounting model of n for the dehydration unit: U_S The accounting model of n for the dehydration unit:

[0115] The dehydration unit is a process link completely required for natural gas production. The raw material is purified natural gas and has nothing to do with sulfur. n = 0. U_S n = 0.

[0116] 4) The accounting model of n for the sulfur recovery, sour water stripping, and sulfur storage and transportation units: U_S The accounting model of n for the sulfur recovery, sour water stripping, and sulfur storage and transportation units:

[0117] The raw material of the sulfur recovery unit is acid gas, the raw material of the sour water stripping unit is sour water, and the raw material of the sulfur storage and transportation unit is sulfur, which is only related to sulfur. Therefore, n = 100%. U_S n = 100%.

[0118] 5) The accounting model of n for the tail gas treatment unit: U_S The accounting model of n for the tail gas treatment unit:

[0119] The accounting models for the hydrogenation furnace, tail gas incinerator, and incinerator fan in the tail gas treatment unit are as follows: U_S are:

[0120]

[0121] The materials processed by other equipment contain acidic gases, all of which are related to sulfur. Therefore, the emissions of other equipment U_S = 100%. In this embodiment, according to each equipment in the unit, the respective U_S of the equipment are calculated separately. And during actual accounting, the equipment with the same proportion in the same unit is combined for calculation.

[0122] (3) Utility engineering proportion model:

[0123] The utility engineering unit provides energy-consuming working fluids for each production unit. Therefore, the accounting is carried out according to the proportion of the consumption of energy-consuming working fluids in each production unit to the production of the utility engineering. The utility engineering proportion model established according to the relationship between the output of the utility engineering energy-consuming working fluids and the consumption of the production unit is as follows:

[0124]

[0125] In the formula:

[0126] E GHG_U_公辅 —The carbon emissions of the utility engineering for each carbon footprint unit, in tCO2 equivalent;

[0127] E GHG_公辅 —The total carbon emissions of the utility engineering, in tCO2 equivalent;

[0128] P 工质_U —The consumption of energy-consuming working fluids for each carbon footprint unit, t or m 3 ;

[0129] P 工质 —The output of the utility engineering energy-consuming working fluids, in t or m 3 .

[0130] In this embodiment, when calculating the process emissions generated by sulfur products using the process emission proportion model, the process emissions are mainly the carbon emissions generated by gas venting in the gathering and transportation unit, desulfurization unit, and sulfur recovery unit. According to the actual statistical gas venting volume of the gathering and transportation unit, desulfurization unit, and sulfur recovery unit, a suitable emission factor is selected, and the gas venting volume is multiplied by the emission factor to calculate the generated process carbon emissions, that is, E GHG_集输δ脱硫制程 , E GHG_硫磺回收制程 in the process emission proportion model. Furthermore, according to the process emission proportion model, the process emission carbon footprint of sulfur products is accounted for.

[0131] In this embodiment, when calculating the emissions generated by the energy consumed by sulfur products using the energy consumption emission ratio model, the total energy emissions E of each production unit GHG_U are determined as follows:

[0132] First step, according to the energy consumption measurement and statistical data, divide the energy consumption of the purification system into each emission unit;

[0133] Second step, summarize the energy consumption data of each emission unit;

[0134] Third step, calculate the product carbon emissions in each emission unit according to the following accounting model formula.

[0135] E GHG =AD×EF×GWP (11)

[0136] In the formula:

[0137] AD - Activity data, various energy consumption amounts; EF - Emission factor; GWP - Global warming potential.

[0138] According to the energy consumption measurement and statistical data, divide the energy consumption of the purification system into each emission unit (i.e., production unit), and allocate it according to the consumption statistics of natural gas and electricity in the purification system. For example, the natural gas in the purification system is mainly consumed in the hydrogenation furnace, tail gas incinerator, Claus reactor, dehydration TEG stripper, etc., and the natural gas consumption is all counted. Allocate according to the proportion of natural gas consumption of each equipment in the natural gas statistical data of each equipment.

[0139] Since there are many power-consuming equipment without measurement in the purification system, the allocation ratio can be determined through actual power balance tests, that is, determine the allocation ratio through the proportion of electricity consumption of each equipment. The public part of the purification system provides services for the production of each carbon footprint unit. The unit energy consumption is high, and the energy consumption required to provide services is also high. Therefore, the allocation ratio of the public part in each carbon footprint unit can be regarded as the same as the consumption ratio of each carbon footprint unit.

[0140] In this embodiment, when calculating the public works carbon emissions of each carbon footprint unit using the public works ratio model, the determination method of public works carbon emissions is similar to the principle of the determination method of E GHG_U , the difference is: divide the energy consumption of public works into each emission unit, and the energy consumption allocation of public works is as follows:

[0141] Public works mainly provides energy-consuming working fluids for each system unit of purification, and all energy consumption is converted to each system unit of purification. The conversion method is as follows:

[0142] The converted energy consumption of each energy-consuming unit = the usage amount of energy-consuming working fluid of each unit / the output of energy-consuming working fluid of public works × the energy consumption of public works.

[0143] Taking the circulating water system as an example, the process of energy consumption division for each unit is described as follows:

[0144] The circulating water system provides circulating water for each unit of the purification system. The consumption amount, proportion, and annual circulating water volume allocated according to the proportion of each unit during the statistical period of circulating water are shown in Table 1.

[0145] Taking the desulfurization unit as an example, the calculation process of the allocated amount is as follows: According to the energy balance test data of the purification device, during the test statistical period, the total circulating water volume of a single purification device is 6030.6 t / h, of which the desulfurization unit is 2719 t / h, and the proportion = 2719 / 6030.9 = 45.09%. The annual total circulating water volume of the circulating water system is 295818872 t / a (statistical data), and the circulating water volume allocated to the desulfurization unit is: 295818872 × 45.09% = 133384729.38 t / a.

[0146] Table 1 Calculation Table of Circulating Water Allocation for Each Unit of the Purification Device

[0147]

[0148] The electricity consumption of the circulating water field during the statistical period is 3541.75×10 4 kWh, and the natural gas volume is 1869.98×10 4 m 3 . This energy consumption is converted according to the circulating water consumption ratio of the desulfurization unit, dehydration unit, tail gas treatment unit, and acid water stripping unit as shown in Table 2.

[0149] Table 2 Conversion Table of Circulating Water Energy Consumption for Each Unit

[0150]

[0151] In this embodiment, the emission factor EF = calorific value × default EF × 10 -9 , where the reference source of the default EF value is the 2006 IPCC National Greenhouse Gas Inventory Guidelines V2_2_Ch2Table2.2, and the reference source of the calorific value is the 2012 China Energy Statistical Yearbook. According to this formula, the calculated emission factors are shown in Tables 3 and 4.

[0152] Table 3 List of Emission Factors

[0153]

[0154]

[0155] Table 4 Baseline Emission Factors for the Chinese Regional Power Grid in 2015

[0156]

[0157] In this embodiment, the global warming potential value GWP is derived from the fifth assessment report of the IPCC in 2013, as shown in Table 5.

[0158] Table 5 List of global warming potential values

[0159]

[0160] Using the carbon footprint accounting method of the present invention, the carbon footprint of sulfur products is calculated one by one according to the gathering and transportation system, desulfurization unit, sulfur recovery unit, tail gas treatment unit, sour water stripping unit, sulfur storage and transportation unit, utilities, and office and living systems. The greenhouse gas emissions of each unit after calculation are shown in Tables 6 and 7.

[0161] Table 6 Carbon emissions of each unit of sulfur products

[0162] Unit to which it belongs <![CDATA[Sulfur product emissions (tCO2e)]]> Proportion (%) Gathering and transportation system 18274.48 2.47 Desulfurization unit 53145.18 7.18 Sulfur recovery unit 439035.38 59.28 Tail gas treatment unit 216650.2 29.25 Acid water stripping unit 3175.21 0.43 Sulfur storage and transportation unit 6118.87 0.83 Office and living system 4211.72 0.57 Total 740611.04 100

[0163] Table 7 Types of carbon emissions of sulfur products

[0164] Emission type <![CDATA[Sulfur product emissions (tCO2e)]]> Proportion (%) Process emission 300718.17 40.60 Fixed source emission 300742.91 40.61 Indirect emission 137057.58 18.51 Mobile source emission 440.27 0.06 Fugitive emission 1652.11 0.22 Total 740611.04 100.00

[0165] According to the calculation results in the above table, the carbon footprint of sulfur products is 740,611.04 tCO2e, and the carbon footprint per unit sulfur is 0.418 tCO2e / t sulfur product.

[0166] After calculating the carbon footprint of sulfur products, the carbon footprint of natural gas products is calculated as follows:

[0167] During the calculation of the carbon footprint of sulfur products, the carbon emissions of emission units such as the gathering and transportation system, desulfurization unit, sulfur recovery unit, tail gas treatment unit, sour water stripping unit, sulfur storage and transportation unit, utilities, and office and living systems are calculated. The total carbon emissions of this part are summarized as follows:

[0168] Table 8 Summary table of carbon emissions (excluding dehydration unit)

[0169] Unit to which it belongs <![CDATA[Total emissions (tCO2e)]]> Gathering and transportation system 48731.45 Desulfurization unit 159728.13 Sulfur recovery unit 1732282.85 Tail gas treatment unit 733280.91 Acid water stripping unit 3175.21 Sulfur storage and transportation unit 6118.87 Office and living 15348.85 Total 2698666.27

[0170] The carbon emission types of the dehydration unit include fixed-source carbon emissions (natural gas combustion) and indirect emissions (electricity consumption). According to the summary results of the energy consumption of each unit of the purification device, the converted natural gas volume of the dehydration unit is 64.29×10 4 m 3 、 and the power consumption is 56.04×10 4 kWh. The corresponding carbon footprint calculations are shown in Tables 9 and 10.

[0171] Table 9 Fixed-source carbon footprint accounting table

[0172]

[0173] Table 10 Indirect Emission Carbon Footprint Accounting Table

[0174]

[0175] According to the above table, the carbon emission of the dehydration unit can be calculated as 1402.88 + 533.22 = 1936.10 tCO2e. The total carbon emission of this gas field is:

[0176] 2698666.27 + 1936.10 = 2700602.37 tCO2e

[0177] According to the carbon footprint accounting method of the present invention, the carbon footprint of sulfur products is calculated as 740611.04 tCO2e, the carbon footprint of natural gas products is 1959991.33 tCO2e, and the carbon footprint per unit of natural gas products is 0.308 kgCO2e / m 3 Natural gas products.

[0178] According to the calculation results, determine the carbon footprint chain of the product from raw material acquisition to the product leaving the production organization. See Appendix Figure 4 (taking sulfur products as an example). The product carbon footprint analysis is carried out layer by layer. First, analyze the main emission units, then analyze the main emission types in the main emission units, further analyze which emission facilities generate the main emission types, and finally focus on the main emission facilities, analyze their influencing factors, and propose carbon footprint improvement measures.

[0179] In this embodiment, the carbon emissions of the auxiliary system are considered. The auxiliary system refers to non-production systems such as office and living. See Appendix Figure 3 . For the calculation of the carbon emissions of co-produced products, since the energy consumption of the auxiliary system is not directly used in production, it cannot be divided by process analysis. Considering that its energy consumption accounts for a very small proportion of the total energy consumption of the gas field, a simple proportional conversion is adopted, that is: the carbon emissions of the auxiliary system attributed to sulfur products = the emissions of the production system attributed to sulfur products × (auxiliary system emissions / production system emissions).

[0180] As another implementation method, since the carbon emissions of the auxiliary system account for a relatively small proportion, if the carbon emissions of the auxiliary system are not considered, then make E GHG_附属 in formula (1) zero, and the calculation formula for the carbon emissions of producing sulfur is as follows:

[0181]

[0182] In the formula, E GHG_S is the carbon emissions of producing sulfur, E GHG_制程 is the process emissions of each carbon footprint unit with the carbon emission type of process emissions, E GHG_生产$E$ is the energy emission of each production unit in the carbon footprint unit with the carbon emission type of energy emission. GHG_公辅 $n$ is the utility carbon emission of each carbon footprint unit. 制程_S $n$ is the proportion of the process emission generated by the product produced by each carbon footprint unit in the total process emission of this unit. U_S $C$ is the proportion of the energy emission consumed by each production unit to produce the product in the total energy emission of this unit. 公辅_S It is the contribution rate of the carbon emission generated by the utility to each production unit.

[0183] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: the specific implementation manners of the present invention can still be modified or equivalently replaced, and any modification or equivalent replacement without departing from the spirit and scope of the present invention shall be covered by the protection scope of the claims of the present invention.

Claims

1. A method for calculating the carbon footprint of high-sulfur gas field products, characterized in that, It includes the following steps: 1) Determine the carbon footprint accounting boundary of high-sulfur gas field products, including: from the wellhead of the gas well to the product leaving the factory, and the product is sulfur or natural gas; 2) Divide the carbon footprint units according to the production processes involved in the carbon footprint accounting boundary, and determine one or several carbon emission types existing in each carbon footprint unit. The carbon emission types at least include energy emissions and process emissions; 3) For the carbon footprint units with carbon emission type of process emissions, namely the gathering and transportation unit, the desulfurization unit, and the sulfur recovery unit, determine the proportion of the process emissions generated by each carbon footprint unit in producing the product in the total process emissions of this carbon footprint unit, multiply this proportion by the process emissions of this carbon footprint unit to obtain the process emissions generated by this carbon footprint unit in producing the product, and add up the process emissions generated by each carbon footprint unit in producing the product to obtain the total process emissions generated in producing the product; among them, the proportion n 制程_S_集输δ脱硫 of the process emissions generated by the gathering / desulfurization unit in producing sulfur products in the total process emissions of the gathering / desulfurization unit is calculated as follows: The proportion n of the process emissions generated by the sulfur recovery unit in producing sulfur products in the total process emissions of the sulfur recovery unit 制程_S_硫磺回收 is calculated as follows: For carbon footprint units with carbon emission type of energy emission, namely gathering and transportation units, desulfurization units, dehydration units, sulfur recovery units, sour water stripping units, sulfur storage and transportation units, and tail gas treatment units, determine the emissions generated by the energy consumed by each production unit in each carbon footprint unit for producing the product, which is the total energy emission of each production unit multiplied by the proportion of the energy emission consumed by each production unit for producing the product in the total energy emission of this production unit. The production unit is the equipment that generates energy emission in the carbon footprint unit; then add up the emissions generated by the energy consumed by each production unit in all carbon footprint units for producing the product to obtain the total emissions generated by the energy consumed for producing the product; among them, the proportion n' of the energy emission consumed by the production unit in the gathering and transportation unit for producing sulfur products in the total energy emission of this production unit U_S The calculation formula is as follows: The proportion n″ of the energy emissions consumed by the production unit in the sulfur production unit in the desulfurization unit or the tail gas treatment unit to the total energy emissions of this production unit U_S The calculation formula is as follows: The proportion of the energy emissions consumed by the production unit in the dehydration unit for producing sulfur products in the total energy emissions of this production unit is zero; the proportion of the energy emissions consumed by the production unit in the sulfur recovery, sour water stripping or sulfur storage and transportation unit for producing sulfur products in the total energy emissions of this production unit is 100%; In each calculation formula, is the proportion of H2S in the feed gas, is the proportion of CO2 in the feed gas, is the proportion of CH4 in the feed gas, is the CO2 content in the natural gas product; 4) Add up the total emissions calculated under various carbon emission types to obtain the carbon emissions of producing the product.

2. The carbon footprint accounting method for high-sulfur gas field products according to claim 1, wherein In step 3), for the carbon footprint units with the carbon emission type of energy emissions, it also includes determining the public works carbon emissions of each carbon footprint unit; the calculation formula for obtaining the carbon emissions of producing the product in step 4) is as follows: where, E GHG_S is the carbon emission of the product, E GHG_制程 is the process emission of each carbon footprint unit with the carbon emission type of process emission, E GHG_生产 is the energy emission of each production unit in the carbon footprint unit with the carbon emission type of energy emission, E GHG_公辅 is the carbon emission of utilities, E GHG_附属 is the emission of the auxiliary system, n 制程_S is the proportion of the process emission generated by each carbon footprint unit in producing the product to the total process emission of this carbon footprint unit, n U_S is the proportion of the energy emission consumed by each production unit in producing the product to the total energy emission of this production unit, C 公辅_S is the contribution rate of the carbon emission generated by utilities to each production unit.

3. The carbon footprint accounting method for high-sulfur gas field products according to claim 2, wherein The calculation formula for the public works carbon emissions of each carbon footprint unit is: where, E GHG_U_公辅 is the utility carbon emissions of each carbon footprint unit, E GHG_公辅 is the total utility carbon emissions, P 工质_U is the consumption of energy-consuming working fluids of each carbon footprint unit, P 工质 is the output of energy-consuming working fluids for utilities.

4. The carbon footprint accounting method for high-sulfur gas field products according to any one of claims 1-3, characterized in that The calculation formula for the process emissions of the gathering or desulfurization unit is: E GHG_S_集输δ脱硫制程 = E GHG_集输δ脱硫制程 × n 制程_S_集输δ脱硫 where E GHG_S_集输δ脱硫制程 is the process emission generated by the sulfur product produced in the gathering and transportation or desulfurization unit, and E GHG_集输δ脱硫制程 is the process emission of the gathering and transportation or desulfurization unit.

5. The carbon footprint accounting method for high-sulfur gas field products according to any one of claims 1-3, characterized in that The calculation formula for the process emissions of the sulfur recovery unit is: E GHG_S_硫磺回收制程 = E GHG_硫磺回收制程 × n 制程_S_硫磺回收 Wherein, E GHG_S_硫磺回收制程 is the process emission generated by the sulfur recovery unit in the production of sulfur products, and E GHG_硫磺回收制程 is the process emission of the sulfur recovery unit.

6. The carbon footprint accounting method for high-sulfur gas field products according to claim 1, wherein The calculation formula for the emissions generated by the energy consumed by each production unit in each carbon footprint unit for producing the product is as follows: E GHG_S_U = E GHG_U × n U_S E GHG_S_U is the energy emission consumed for producing sulfur by each production unit in each carbon footprint unit, E GHG_U is the total energy emission of each production unit in each carbon footprint unit, n U_S is the proportion of the energy emission consumed for producing sulfur products by the production unit in the total energy emission of this production unit.

Images