Quantitative evaluation method and device for full-life-cycle carbon footprint of sulfuric acid circulating symbiotic utilization system

Abstract

The invention discloses a full-life-cycle carbon footprint quantitative evaluation method and device for a sulfuric acid circulating symbiotic utilization system. The method comprises the following steps: 1) dividing subsystems in the full life cycle of the sulfuric acid circulating symbiotic utilization system and determining a system boundary of carbon footprint quantitative evaluation; 2) determining a carbon emission source of sulfuric acid in each subsystem according to a production process, and constructing a carbon emission list; 3) determining a carbon emission calculation method of each emission source, and constructing a carbon footprint quantitative evaluation model; 4, activity data and carbon emission factors of all carbon emission sources are established, and the carbon footprint of the sulfuric acid circulation symbiotic utilization system.By means of the method, the full-life-cycle emission reduction target function of the sulfuric acid circulation symbiotic utilization system can be determined, and a carbon footprint optimization scheme is formed for different circulation symbiotic utilization scenes.

Description

Technical Field

[0001] The present invention relates to the field of carbon footprint quantification and evaluation, and specifically to a method and device for quantifying the life cycle carbon footprint of an industrial symbiotic system for sulfuric acid recycling in a system composed of nitration reaction, diazotization reaction, coupling reaction of aromatic compounds, and acidolysis reaction of aromatic amines. Background Art

[0002] As an important chemical raw material, sulfuric acid is widely used in the production of dyes and organic chemical intermediates. In this process, sulfuric acid is usually used as a reaction medium (such as nitration reaction, diazotization reaction, coupling reaction), and can also be used as a reaction raw material (such as acidolysis reaction of aromatic amines). After use, the concentration of sulfuric acid usually decreases, generating a large amount of acidic wastewater. Reducing waste generation and saving sulfuric acid consumption through sulfuric acid recycling and symbiotic utilization to achieve synergistic pollution reduction and carbon reduction has become an industry consensus.

[0003] However, there is still little research on the carbon emissions of the sulfuric acid recycling and symbiotic utilization system during the reaction process of dyes and organic chemical intermediates, and there is a lack of a quantitative method for systematically evaluating its pollution reduction and carbon reduction effectiveness. At the same time, in different production systems, the concentration of sulfuric acid often varies significantly, and the types and quantities of used sulfuric acid and the materials and energy used in its treatment process are also different. It is necessary to establish a calculation method for the carbon emissions of the sulfuric acid recycling and symbiotic utilization process according to the actual operating conditions of the system.

[0004] Most sulfuric acid production adopts the sulfur-burning process to produce sulfuric acid. A large amount of chemical reaction heat released during the reaction process can co-produce electricity and steam, replacing the use of fossil energy, and having good carbon reduction benefits. When the used sulfuric acid is recycled and symbiotically utilized, it is coupled with the sulfur-burning process to produce sulfuric acid. By supplementing sulfur trioxide, the concentration of dilute sulfuric acid is increased, reducing the energy consumption and cost of the dilute sulfuric acid concentration and purification process. At the same time, it can also improve the adaptability of sulfuric acid with different concentration gradients to the nitration reaction, diazotization reaction, coupling reaction of aromatic compounds, and acidolysis reaction system of aromatic amines. However, existing research still lacks a method for quantifying the pollution reduction and carbon reduction performance and comprehensive optimization of the system under different coupling strategies of sulfuric acid regeneration, symbiotic utilization, and sulfur-burning process to produce sulfuric acid.

[0005] To solve the problems existing in the prior art, it is necessary to clarify the material flow and energy flow of the sulfuric acid recycling and symbiotic utilization system. From the perspectives of systems engineering and the whole life cycle, a method for quantifying the carbon footprint of the sulfuric acid recycling and symbiotic utilization system is constructed to depict the material flow, energy flow, and carbon emissions in each link of sulfuric acid preparation, dilute sulfuric acid concentration treatment, purification, recycling, symbiotic utilization, and resource disposal during the reaction process of dyes and organic intermediates, and to establish a multi-objective comprehensive optimization method for pollution reduction and carbon reduction of the sulfuric acid recycling and symbiotic utilization system. Summary of the Invention

[0006] The present invention aims to overcome the above-mentioned drawbacks of the prior art and provides a method and device for quantitatively evaluating the carbon footprint of the entire life cycle of a sulfuric acid recycling and symbiotic utilization system.

[0007] For production systems involving the use of sulfuric acid such as the nitration reaction, diazotization reaction, coupling reaction, and acidolysis reaction of aromatic amino acids of aromatic compounds, the present invention constructs a sulfuric acid recycling and regeneration and symbiotic utilization system, quantifies the carbon footprint of sulfuric acid at different concentrations under methods such as recycling utilization, cascade utilization, resource treatment and disposal, and compares the carbon footprint differences with those when taking conventional measures to produce the same products, so as to identify the key links of carbon emissions in the entire life cycle of sulfuric acid, evaluate the carbon emission reduction benefits obtained by different concentrations of sulfuric acid through different recycling and symbiotic utilization methods, and identify the preferred recycling and symbiotic utilization schemes. The present invention can provide decision-making support for sulfuric acid production and use enterprises and help achieve the goal of reducing pollution and carbon emissions.

[0008] A method for quantitatively evaluating the carbon footprint of the entire life cycle of a sulfuric acid recycling and symbiotic utilization system according to the present invention includes the following steps:

[0009] 1) Divide subsystems in the entire life cycle of the sulfuric acid recycling and symbiotic utilization system and determine the system boundary for quantitative evaluation of the carbon footprint;

[0010] 2) Determine the carbon emission sources of sulfuric acid in each subsystem according to the production process and construct a carbon emission inventory;

[0011] 3) Determine the carbon emission calculation methods for each emission source and construct a quantitative evaluation model of the carbon footprint;

[0012] 4) Establish the activity data and carbon emission factors of each carbon emission source and calculate the carbon footprint of the sulfuric acid recycling and symbiotic utilization system.

[0013] Through the above method, the emission reduction objective function of the entire life cycle of the sulfuric acid recycling and symbiotic utilization system can be determined, and a carbon footprint optimization plan can be formed for different recycling and symbiotic utilization scenarios.

[0014] Preferably, the boundary of the sulfuric acid recycling and symbiotic utilization system described in step 1) is all processes from the production of sulfuric acid to the treatment and disposal of acid-containing wastewater, including four types of subsystems: ① sulfuric acid use subsystem, ② sulfuric acid concentration and recycling subsystem, ③ sulfuric acid symbiotic utilization subsystem, and ④ acid-containing wastewater disposal subsystem.

[0015] The carbon footprint calculation formula of the sulfuric acid recycling and symbiotic utilization system is:

[0016] (1)

[0017] In the formula:

[0018] is the carbon footprint of the sulfuric acid recycling and symbiotic utilization system, with the unit of kg CO2 eq;

[0019] is the carbon emission of the th sulfuric acid usage subsystem, in kg CO2 eq;

[0020] is the th carbon emission of the sulfuric acid concentration and recycling subsystem, in kg CO2 eq;

[0021] is the th carbon emission of the sulfuric acid co - utilization subsystem, in kg CO2 eq;

[0022] is the th carbon emission of the acid - containing wastewater treatment subsystem, in kg CO2 eq.

[0023] ① Sulfuric acid usage subsystem

[0024] The said sulfuric acid usage subsystem is: After sulfuric acid is prepared, it participates in a round of reaction process, and the dilute sulfuric acid generated after the reaction enters the subsequent treatment and disposal process in the form of acid - containing wastewater.

[0025] The carbon emission sources of the said sulfuric acid usage subsystem include: Carbon emissions generated during sulfuric acid preparation and carbon emissions generated during acid - containing wastewater treatment.

[0026] The formula for calculating the carbon emission of the sulfuric acid usage subsystem is:

[0027] (2)

[0028] In the formula:

[0029] is the th carbon emission of the sulfuric acid usage subsystem, in kg CO2 eq;

[0030] is the th mass of new sulfuric acid used in the sulfuric acid usage subsystem, in kg;

[0031] is the carbon emission factor of sulfuric acid from cradle to gate, in kg CO2 eq / kg.

[0032] The calculation of carbon emissions generated from the treatment of acid - containing wastewater produced by the sulfuric acid usage subsystem refers to ④ Acid - containing wastewater treatment subsystem.

[0033] ② Sulfuric acid concentration and recycling subsystem

[0034] The sulfuric acid concentration and recycling subsystem is as follows: After sulfuric acid is prepared, it participates in a round of reaction process. The sulfuric acid after the reaction is concentrated and then recycled to the previous reaction process.

[0035] The carbon emission sources of the sulfuric acid concentration and recycling subsystem include: carbon emissions generated during the sulfuric acid preparation process, carbon emissions generated from the energy consumed during the sulfuric acid concentration process, carbon emissions generated from chemical reagents such as sulfur trioxide added in some concentration processes, carbon emissions generated from the disposal of some acid-containing wastewater after sulfuric acid recycling, and the carbon performance brought about by replacing part of the new sulfuric acid after sulfuric acid recycling.

[0036] The calculation formula for the carbon emissions of the sulfuric acid concentration and recycling subsystem is:

[0037] (3)

[0038] In the formula:

[0039] is the carbon emission of the th sulfuric acid concentration and recycling subsystem, with the unit of kg CO2 eq;

[0040] is the carbon emission during the preparation process of the sulfuric acid required in the th sulfuric acid concentration and recycling subsystem, with the unit of kgCO2 eq;

[0041] is the carbon emission of the sulfuric acid concentration in the th sulfuric acid concentration and recycling subsystem, with the unit of kg CO2 eq;

[0042] is the carbon performance of the sulfuric acid recycling in the th sulfuric acid concentration and recycling subsystem, with the unit of kg CO2 eq.

[0043] The calculation formula for the carbon emissions during the preparation process of the sulfuric acid required for the reaction process is:

[0044] (3a)

[0045] In the formula:

[0046] is the carbon emission during the preparation process of the sulfuric acid required for the reaction process in the th sulfuric acid concentration and recycling subsystem, with the unit of kg CO2 eq / kg;

[0047] is the th sulfuric acid concentration and recycling subsystem, with the unit of kg;

[0048] is the cradle-to-gate carbon emission factor of sulfuric acid, with the unit of kg CO2 eq / kg.

[0049] The calculation formula for the emissions during the sulfuric acid concentration process is:

[0050] (3b)

[0051] In the formula:

[0052] is the carbon emission during the sulfuric acid concentration process in the th sulfuric acid concentration cycle subsystem, with the unit of kg CO2eq / kg;

[0053] is the amount of steam consumed during the sulfuric acid concentration process, with the unit of MJ;

[0054] is the carbon emission factor of steam, with the unit of kg CO2 eq / MJ;

[0055] is the electricity consumed during the sulfuric acid concentration process, with the unit of kW·h;

[0056] is the carbon emission factor of electricity, with the unit of kg CO2 eq / kW·h; Some sulfuric acid concentration processes use fossil fuels such as coal or natural gas. is the amount of the th fossil fuel consumed in this process, with the unit of kg or Nm 3 ;

[0057] is the th carbon emission factor of fossil fuel, with the unit of kg CO2 eq / kg or kg CO2 eq / Nm 3 ;

[0058] is the mass of the th chemical consumed during the sulfuric acid concentration process, with the unit of kg;

[0059] is the th cradle-to-gate carbon emission factor of chemical, with the unit of kg CO2 eq / kg.

[0060] The calculation formula for the sulfuric acid cycle carbon performance is:

[0061] (3c)

[0062] In the formula:

[0063] is the carbon performance of sulfuric acid circulation in the th sulfuric acid concentration and circulation subsystem, with the unit of kg CO2 eq;

[0064] is the mass of recycled sulfuric acid, with the unit of kg;

[0065] is the carbon emission factor of sulfuric acid from cradle to gate, with the unit of kg CO2 eq / kg.

[0066] The calculation of carbon emissions generated from the disposal of acid-containing wastewater produced by the sulfuric acid concentration and circulation subsystem refers to the acid-containing wastewater disposal subsystem in ④.

[0067] ③ Sulfuric acid co-utilization subsystem

[0068] The sulfuric acid co-utilization subsystem is as follows: After sulfuric acid is prepared, it participates in one reaction process. The sulfuric acid after the reaction is purified and then participates in another reaction process, forming a symbiotic relationship between the two different reaction processes. After one or more layers of symbiosis, the used sulfuric acid enters the subsequent treatment and disposal process in the form of acid-containing wastewater.

[0069] The carbon emission sources of the sulfuric acid co-utilization subsystem include: carbon emissions generated during the sulfuric acid preparation process, carbon emissions generated during the preparation of chemical reagents such as activated carbon, flocculants, and oxidants consumed during the sulfuric acid purification process, carbon emissions generated when the acid-containing wastewater enters the subsequent treatment and disposal process, and the carbon performance brought about by replacing part of the new sulfuric acid during sulfuric acid symbiosis.

[0070] The formula for calculating the carbon emissions of the sulfuric acid co-utilization subsystem is:

[0071] (4)

[0072] In the formula:

[0073] is the th carbon emission of the sulfuric acid co-utilization subsystem, with the unit of kg CO2 eq;

[0074] is the th carbon emission generated during the preparation of sulfuric acid required for the reaction process in the sulfuric acid co-utilization subsystem, with the unit of kg CO2 eq;

[0075] is the th carbon emission generated during the purification process of the sulfuric acid co-utilization subsystem, with the unit of kg CO2 eq;

[0076] is the The carbon performance of sulfuric acid co - utilization in the sulfuric acid co - utilization subsystem, with the unit of kg CO2eq.

[0077] The carbon emission calculation formula for the preparation process of sulfuric acid required in the reaction process is:

[0078] (4a)

[0079] In the formula:

[0080] is the carbon emission during the preparation process of sulfuric acid required in the th sulfuric acid co - utilization subsystem, with the unit of kgCO2 eq;

[0081] is the mass of new sulfuric acid required for the first reaction process in the th sulfuric acid co - utilization subsystem, with the unit of kg;

[0082] is the mass of new sulfuric acid required for the second reaction process in the th sulfuric acid co - utilization subsystem, with the unit of kg;

[0083] is the carbon emission factor of sulfuric acid from cradle to gate, with the unit of kg CO2 eq / kg.

[0084] The carbon emission calculation formula for the purification process of the sulfuric acid co - utilization subsystem is:

[0085] (4b)

[0086] In the formula:

[0087] is the carbon emission generated during the purification process of the th sulfuric acid co - utilization subsystem, with the unit of kg CO2eq;

[0088] is the amount of electricity consumed in the sulfuric acid purification process, with the unit of kW·h;

[0089] is the carbon emission factor of electricity, with the unit of kg CO2 eq / kW·h;

[0090] is the amount of the th fossil energy consumed, with the unit of kg or Nm 3 ;

[0091] is the Carbon emission factor of the fossil energy source, in kg CO2 eq / kg or kg CO2 eq / Nm 3 ;

[0092] It is The sulfuric acid symbiotic utilization subsystem consumes the first The mass of the chemical reagent, in kg;

[0093] It is The cradle-to-gate carbon emission factors for the chemical agents are expressed in kg CO2 eq / kg.

[0094] The calculation formula for the carbon performance of sulfuric acid symbiosis is:

[0095] (4c)

[0096] Where:

[0097] It is The carbon performance of sulfuric acid symbiotic utilization in each sulfuric acid symbiotic utilization subsystem, in kg CO2eq;

[0098] It is The amount of new sulfuric acid saved through symbiotic utilization in each sulfuric acid symbiotic utilization subsystem, in kg;

[0099] is the cradle-to-gate carbon emission factor for sulfuric acid, expressed in kg CO2 eq / kg.

[0100] In the sulfuric acid symbiotic utilization subsystem, the calculation formula for the amount of new sulfuric acid saved is:

[0101] (4c-1)

[0102] Where:

[0103] It is The amount of new sulfuric acid saved through symbiotic utilization in each sulfuric acid symbiotic utilization subsystem, in kg;

[0104] It is The mass fraction of sulfuric acid that enters the next reaction process after purification in each sulfuric acid symbiotic utilization subsystem, unit is %

[0105] It is The mass fraction of new sulfuric acid used in each sulfuric acid symbiotic utilization subsystem, in %, is usually 98%;

[0106] is the mass of sulfuric acid that enters the next reaction process after purification in the

[0107] For the calculation of carbon emissions generated from the disposal of acid-containing wastewater produced by the sulfuric acid co-utilization subsystem, refer to ④ Acid-containing wastewater disposal subsystem.

[0108] ④ Acid-containing wastewater disposal subsystem

[0109] The acid-containing wastewater disposal subsystem is as follows: The acid-containing wastewater generated in each production link is combined and then neutralized, purified, and concentrated and crystallized to be converted into sulfates, achieving harmlessness and resource utilization.

[0110] The carbon emission sources of the acid-containing wastewater disposal subsystem include: a) Carbon emissions generated during the neutralization process of acid-containing wastewater, b) Carbon emissions during the purification process of acid-containing wastewater, c) Carbon emissions during the concentration and crystallization process of acid-containing wastewater, d) Carbon performance of the recovered by-product sulfates.

[0111] The calculation formula for the carbon emissions of the acid-containing wastewater disposal subsystem is:

[0112] (5)

[0113] In the formula:

[0114] is the carbon emissions of the

[0115] is the carbon emissions during the neutralization process of acid-containing wastewater in the

[0116] is the carbon emissions during the purification process in the

[0117] is the carbon emissions during the concentration and crystallization process in the

[0118] is the carbon performance of the by-product sulfates in the

[0119] a) Carbon emissions generated during the neutralization process of acid-containing wastewater

[0120] The carbon emissions during the neutralization process of acid-containing wastewater include the carbon emissions generated by the energy used and the carbon emissions generated during the preparation of alkaline chemical reagents such as ammonia or lime added. The calculation formula is as follows:

[0121] (5a)

[0122] In the formula:

[0123] is the carbon emissions during the neutralization process of acid-containing wastewater in the th acid-containing wastewater treatment subsystem, in units of kgCO2 eq;

[0124] is the amount of steam consumed during the neutralization process of acid-containing wastewater, in units of MJ;

[0125] is the carbon emission factor of steam, in units of kg CO2 eq / MJ;

[0126] is the amount of electricity consumed during the neutralization process of acid-containing wastewater, in units of kW·h;

[0127] is the carbon emission factor of electricity, in units of kg CO2 eq / kW·h;

[0128] is the mass of the th chemical reagent consumed during the neutralization process of acid-containing wastewater, in units of kg;

[0129] is the th cradle-to-gate carbon emission factor of the chemical reagent, in units of kg CO2 eq / kg.

[0130] b) Carbon emissions during the purification process of acid-containing wastewater

[0131] The carbon emissions during the purification process of acid-containing wastewater include the carbon emissions generated by the electricity, fossil energy, and chemical reagents used during the purification process. The calculation formula is as follows:

[0132] (5b)

[0133] In the formula:

[0134] is the carbon emissions during the purification process in the th acid-containing wastewater treatment subsystem, in units of kg CO2 eq;

[0135] is the amount of electricity consumed during the purification process of acid-containing wastewater, in units of kW·h;

[0136] is the carbon emission factor of electricity, with the unit of kg CO2 eq / kW·h;

[0137] is the amount of the th fossil energy consumed in the purification process of acid-containing wastewater. When the consumed fossil energy is coal, the unit is kg; when the consumed fossil energy is natural gas, the unit is Nm 3 ;

[0138] is the th carbon emission factor of fossil energy, with the unit of kg CO2 eq / kg or kg CO2 eq / Nm 3 ;

[0139] is the mass of the th chemical reagent consumed in the purification process of acid-containing wastewater, with the unit of kg;

[0140] is the th cradle-to-gate carbon emission factor of chemical reagent, with the unit of kg CO2 eq / kg.

[0141] c) Carbon emissions in the process of concentrating and crystallizing acid-containing wastewater

[0142] The carbon emissions in the process of concentrating and crystallizing acid-containing wastewater include the carbon emissions generated by electricity, steam and fossil energy used during concentration and crystallization. The calculation formula is:

[0143] (5c)

[0144] In the formula:

[0145] is the carbon emission in the process of concentrating and crystallizing in the th acid-containing wastewater treatment subsystem, with the unit of kg CO2eq;

[0146] is the amount of steam consumed in the process of concentrating and crystallizing acid-containing wastewater, with the unit of MJ;

[0147] is the carbon emission factor of steam, with the unit of kg CO2 eq / MJ;

[0148] is the amount of electricity consumed in the process of concentrating and crystallizing acid-containing wastewater, with the unit of kW·h;

[0149] is the carbon emission factor of electricity, with the unit of kg CO2 eq / kW·h;

[0150] is the quantity of the th type of fossil energy consumed in the concentrated crystallization process of acid-containing wastewater. When the consumed fossil energy is coal, the unit is kg; when the consumed fossil energy is natural gas, the unit is Nm 3 ;

[0151] is the th type of fossil energy's carbon emission factor, with the unit of kg CO2 eq / kg or kg CO2 eq / Nm 3 .

[0152] d) Carbon performance of the recovered by-product sulfate

[0153] The calculation formula for the carbon performance of the by-product sulfate in the acid-containing wastewater treatment subsystem is:

[0154] (5d)

[0155] In the formula:

[0156] is the th carbon performance of the by-product sulfate in the

[0157] th acid-containing wastewater treatment subsystem, with the unit of kg CO2 eq; is the mass of the by-product sulfate in the

[0158] th acid-containing wastewater treatment subsystem, with the unit of kg;

[0159] The target parameters in the life cycle emission reduction objective function of the sulfuric acid recycling and symbiotic utilization system described in step 5) include: the life cycle carbon emissions of the system, the treatment and emissions of acid-containing wastewater, and the life cycle operation cost and benefits of the system.

[0160] The variables when setting different recycling and symbiotic utilization scenarios include: the quantities of sulfuric acid with different concentrations respectively undergoing concentrated treatment, recycled use, symbiotic utilization, and directly used for the treatment of acid-containing wastewater.

[0161] The second aspect of the present invention relates to a device for quantitatively evaluating the life cycle carbon footprint of a sulfuric acid recycling and symbiotic utilization system, including a memory and one or more processors. The memory stores executable code, and when the one or more processors execute the executable code, it is used to implement the method for quantitatively evaluating and optimizing the life cycle carbon footprint of the sulfuric acid recycling and symbiotic utilization system of the present invention.

[0162] The advantages of the present invention are as follows: A carbon emission inventory and carbon footprint quantification evaluation model for the entire life cycle of a sulfuric acid recycling and symbiotic utilization system with a more complete system, clearer modular unit processes, and wider applicability is constructed. Corresponding carbon emission calculation methods are constructed for the entire life cycle of sulfuric acid from production to use and then to waste treatment and disposal, improving the comprehensiveness and usability of the model, providing more complete and comprehensive carbon emission data for decision-makers, and promoting the reduction of the overall carbon footprint of the sulfuric acid industrial chain. The use process of sulfuric acid is divided into three categories: new sulfuric acid use, sulfuric acid concentration recycling, and sulfuric acid symbiotic utilization. Different processes can be flexibly combined according to the requirements of the product system and reaction system for the concentration and quality of sulfuric acid, forming a carbon footprint accounting model for sulfuric acid use systems with a wide range of applicability, enabling the scientific quantification of the carbon emission benefits of different sulfuric acid use modes.

[0163] On this basis, an optimization method for the sulfuric acid recycling and symbiotic utilization system is established, which can provide data support for decision-makers to optimize the reaction process and use sulfuric acid efficiently and with low carbon emissions. BRIEF DESCRIPTION OF THE DRAWINGS

[0164] Figure 1 is a schematic flow chart of the method of the present invention;

[0165] Figure 2 is a schematic diagram of the boundaries of the sulfuric acid recycling and symbiotic utilization system and its subsystems in the present invention.

[0166] Figure 3 is a schematic diagram of the sulfuric acid recycling and symbiotic utilization system in the dye and intermediate production system.

[0167] Figure 4 is a carbon footprint distribution diagram of the sulfuric acid symbiotic utilization system in the dye intermediate production system.

[0168] Figure 5 is a schematic diagram of the device for quantifying the carbon footprint of the entire life cycle of the sulfuric acid recycling and symbiotic utilization system in the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0169] To better understand the technical solutions and effects of the present invention, the following will refer to the accompanying drawings and describe specifically and clearly in combination with the embodiments of the present invention. However, it should be understood that these descriptions are only exemplary and not all embodiments, only facilitating better understanding of the present invention by those skilled in the art, and not intended to limit the scope protected by the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the protection scope of the present invention.

[0170] In addition, in the following description, descriptions of well-known common knowledge and technologies are omitted to avoid unnecessarily confusing the concepts of the present disclosure. All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted to have meanings consistent with the context of this specification, and should not be interpreted in an idealized or overly rigid manner.

[0171] Example 1

[0172] As Figure 1 shown, a method for quantifying and evaluating the life-cycle carbon footprint of a sulfuric acid recycling and co-utilization system includes the following steps:

[0173] 1) Divide subsystems in the life cycle of the sulfuric acid recycling and co-utilization system and determine the system boundary for carbon footprint quantification and evaluation;

[0174] 2) Determine the carbon emission sources of sulfuric acid in each subsystem according to the production process and construct a carbon emission inventory;

[0175] 3) Determine the carbon emission calculation methods for each emission source and construct a carbon footprint quantification and evaluation model;

[0176] 4) Establish the activity data and carbon emission factors for each carbon emission source and calculate the carbon footprint of the sulfuric acid recycling and co-utilization system;

[0177] 5) Determine the life-cycle emission reduction objective function of the sulfuric acid recycling and co-utilization system and form a carbon footprint optimization plan for different recycling and co-utilization scenarios.

[0178] As Figure 2 shown, the boundary of the sulfuric acid recycling and co-utilization system is all processes from the production of sulfuric acid to the treatment and disposal of acid-containing wastewater in the sulfuric acid life cycle, including four types of subsystems: ① sulfuric acid use subsystem, ② sulfuric acid concentration and recycling subsystem, ③ sulfuric acid co-utilization subsystem, ④ acid-containing wastewater disposal subsystem.

[0179] In the present invention, by dividing the sulfuric acid recycling and co-utilization system into different subsystems, the carbon emissions of different sulfuric acid use modes can be more clearly identified, calculated, and managed. Through the separate calculation of the carbon emissions of each subsystem, the carbon emission differences of sulfuric acid with the same concentration under different use modes can be more intuitively compared, and then targeted emission reduction measures can be taken in the construction and process optimization of the production process system. Different types and different subsystems of the same type can be combined with each other, so as to simulate the complex sulfuric acid recycling and co-utilization system with multiple reaction processes, sulfuric acid with different concentrations, and integrated coupling of various subsystems in the actual chemical engineering scenario, making the applicability of the carbon footprint calculation method of the present invention more extensive.

[0180] ① Sulfuric acid use subsystem

[0181] The sulfuric acid usage subsystem is the basic mode of sulfuric acid usage in the chemical reaction process, and its boundary is from sulfuric acid preparation to the conversion of sulfuric acid into acid-containing wastewater for disposal. In this subsystem, after sulfuric acid preparation is completed, it is put into a specific reaction process. After reacting with other raw and auxiliary materials, it exists in the form of acid-containing wastewater and enters the subsequent recycling, symbiotic, treatment, and disposal links. In this subsystem, sulfuric acid carbon emissions come from the sulfuric acid preparation process and the acid-containing wastewater disposal process. Calculating the carbon emissions of this subsystem can quantitatively evaluate the emissions of the chemical production system when no sulfuric acid recycling or symbiotic utilization measures are taken, and provide a control benchmark for evaluating the carbon emission reduction performance of sulfuric acid recycling or symbiotic utilization measures.

[0182] ② Sulfuric acid concentration and recycling subsystem

[0183] The sulfuric acid concentration and recycling subsystem includes sulfuric acid preparation, sulfuric acid usage, sulfuric acid concentration treatment, and sulfuric acid recycling. In this subsystem, the used sulfuric acid is concentrated and treated by physical or chemical methods and then reused in the reaction process to replace new sulfuric acid. The content of carbon footprint calculation for this subsystem includes: carbon emissions generated during the preparation of new sulfuric acid entering the subsystem, carbon emissions generated during the concentration and disposal of dilute sulfuric acid after participating in the reaction, and carbon performance brought by sulfuric acid recycling. Different reaction processes require different sulfuric acid concentrations, and the carbon emissions generated during the concentration and disposal of dilute sulfuric acid will also change accordingly. The higher the requirement for increasing the concentration of dilute sulfuric acid, the more energy and chemicals consumed in the concentration process, the corresponding higher the carbon emissions, and the lower the overall carbon performance of the concentration and recycling subsystem. By calculating the carbon footprint of this subsystem, the carbon emissions of sulfuric acid concentration and recycling at different concentrations can be quantitatively characterized, and it can be accurately evaluated whether the overall process increases or reduces carbon, thus helping decision-makers design a more low-carbon sulfuric acid recycling system more scientifically.

[0184] ③ Sulfuric acid symbiotic utilization subsystem

[0185] The sulfuric acid co-utilization subsystem consists of at least two reaction processes in series. In this subsystem, after sulfuric acid is prepared, it is fed into the reaction process. After the reaction, the concentration decreases. The sulfuric acid with a lower concentration is purified and then fed into another reaction process with a lower requirement for sulfuric acid concentration as a raw material, replacing part of the fresh sulfuric acid. Thus, a layer of sulfuric acid co-utilization relationship is formed between the two different reaction processes. In engineering practice, according to the sulfuric acid concentration required for different reaction processes and the change in sulfuric acid concentration after the reaction, one or more layers of sulfuric acid co-utilization relationships can be constructed to make full use of sulfuric acid. Finally, the part that is difficult to be utilized enters the subsequent treatment and disposal process in the form of acid-containing wastewater. Since there are differences in the sulfuric acid concentration and the corresponding purification process involved in each layer of sulfuric acid co-utilization relationship, the carbon emissions need to be calculated separately. Therefore, in the method constructed in the present invention, each layer of sulfuric acid co-utilization relationship is divided into a sulfuric acid co-utilization subsystem. By calculating the carbon footprint of this subsystem, the carbon emissions brought by purification and the carbon performance brought by replacing fresh sulfuric acid in the sulfuric acid co-utilization process can be comprehensively quantified, and the carbon performance of sulfuric acid co-utilization systems with different concentration gradients can be accurately evaluated. By calculating the carbon emissions of multiple sulfuric acid co-utilization subsystems separately and then summing them up, the carbon emissions of multi-layer sulfuric acid co-utilization relationships can be quantitatively evaluated, realizing the quantitative characterization of the carbon emissions of complex sulfuric acid co-utilization systems and helping the low-carbon design and optimization of the overall system.

[0186] ④ Acid-containing wastewater treatment and disposal subsystem

[0187] The acid-containing wastewater treatment and disposal subsystem is the end link of the life cycle of sulfuric acid. After sulfuric acid goes through different usage links, it enters this subsystem in the form of acid-containing wastewater. In this subsystem, first, sulfuric acid is converted into sulfate by a neutralization reaction with alkaline substances containing ammonia, magnesium, and calcium. Then, the sulfate and impurities in the solution are removed through a purification method. Furthermore, high-efficiency concentration and crystallization processes such as steam mechanical recompression (MVR) and multi-effect evaporation are used to separate the sulfate, and finally, the high-efficiency utilization of sulfuric acid is realized. The carbon emissions of this subsystem mainly come from the chemical substances used in the neutralization process and the purification process, as well as the consumed energy; the recovery of sulfate can generate certain carbon performance. Currently, ammonia neutralization is mainly used to by-produce ammonium sulfate, and some processes produce magnesium sulfate or calcium sulfate, and further hazardous waste disposal is carried out. By calculating the carbon footprint of this subsystem, the carbon emissions when different disposal processes are used for sulfuric acid with different concentrations can be quantitatively evaluated, helping decision-makers choose a more low-carbon treatment and disposal method from the perspective of synergistic reduction of pollution and carbon emissions.

[0188] In the sulfuric acid recycling and co-utilization system, carbon emissions are generated during the use of sulfuric acid, while the sulfuric acid concentration and recycling process, sulfuric acid co-utilization process, and acid-containing wastewater treatment and disposal process all involve both carbon emissions and carbon performance, and vary with the differences in sulfuric acid concentration and actual working conditions in each chemical process. This requires a more systematic and comprehensive method to evaluate the carbon footprint of the entire life cycle.

[0189] In the full - life - cycle carbon footprint accounting of the sulfuric acid recycling symbiotic utilization system, based on production practice, the use process of sulfuric acid is divided into four types of subsystems. Flexible combinations between different subsystems can construct diverse sulfuric acid recycling symbiotic utilization systems, thereby depicting the carbon footprints of sulfuric acid recycling symbiotic utilization systems in different product systems and supporting decision - makers in selecting appropriate options.

[0190] Specifically, the calculation method of the carbon emissions of the sulfuric acid recycling symbiotic utilization system is as follows:

[0191] It should be noted that the calculation of the carbon emissions in the acid - containing wastewater treatment and disposal processes involved in ① the sulfuric acid use subsystem, ② the sulfuric acid concentration and recycling subsystem, and ③ the sulfuric acid symbiotic utilization subsystem is the same as the calculation method of the carbon emissions in ④ the acid - containing wastewater disposal subsystem, and will not be elaborated one by one.

[0192] ① Sulfuric acid use subsystem

[0193] The calculation formula for the carbon emissions of the sulfuric acid use subsystem is:

[0194] (2)

[0195] In the formula:

[0196] is the carbon emission of the th sulfuric acid use subsystem, with the unit of kg CO2 eq;

[0197] is the th mass of new sulfuric acid used in the sulfuric acid use subsystem, with the unit of kg;

[0198] is the carbon emission factor of sulfuric acid from cradle to gate, with the unit of kg CO2 eq / kg.

[0199] ② Sulfuric acid concentration and recycling subsystem

[0200] The calculation formula for the carbon emissions of the sulfuric acid concentration and recycling subsystem is:

[0201] (3)

[0202] In the formula:

[0203] is the carbon emission of the th sulfuric acid concentration and recycling subsystem, with the unit of kg CO2 eq;

[0204] is the th carbon emission in the preparation process of the sulfuric acid required in the sulfuric acid concentration and recycling subsystem, with the unit of kgCO2 eq;

[0205] is the carbon emission of sulfuric acid concentration treatment in the th sulfuric acid concentration cycle subsystem, with the unit of kg CO2 eq;

[0206] is the carbon performance of sulfuric acid circulation in the th sulfuric acid concentration cycle subsystem, with the unit of kg CO2 eq.

[0207] In the sulfuric acid concentration cycle subsystem, sulfuric acid enters the reaction process as a reaction raw material. Indirect carbon emissions will be generated during the preparation of this part of sulfuric acid. The calculation formula for the carbon emission of sulfuric acid required for the reaction process during preparation is:

[0208] (3a)

[0209] In the formula:

[0210] is the carbon emission of sulfuric acid required for the reaction process during preparation in the th sulfuric acid concentration cycle subsystem, with the unit of kg CO2 eq / kg;

[0211] is the mass of new sulfuric acid required for the reaction process in the th sulfuric acid concentration cycle subsystem, with the unit of kg;

[0212] is the carbon emission factor of sulfuric acid from cradle to gate, with the unit of kg CO2 eq / kg.

[0213] The concentration of sulfuric acid decreases after the reaction process. If it is recycled, concentration and purification treatments are required. For example, physical concentration processes such as vacuum concentration and kettle concentration can be used to heat and concentrate to remove water and increase the sulfuric acid concentration, or sulfur trioxide can be added to increase the concentration. The carbon emissions of this process come from the consumed energy and chemical reagents such as added sulfur trioxide. The calculation formula for the emissions during the sulfuric acid concentration treatment process is:

[0214] (3b)

[0215] In the formula:

[0216] is the carbon emission of the sulfuric acid concentration process in the th sulfuric acid concentration cycle subsystem, with the unit of kg CO2eq / kg;

[0217] is the amount of steam consumed during the sulfuric acid concentration treatment process, with the unit of MJ;

[0218] is the carbon emission factor of steam, with the unit of kg CO2 eq / MJ;

[0219] is the electricity consumed in the sulfuric acid concentration process, with the unit of kW·h;

[0220] is the carbon emission factor of electricity, with the unit of kg CO2 eq / kW·h; Some sulfuric acid concentration processes use fossil fuels such as coal or natural gas, is the amount of the th type of fossil fuel consumed in this process, with the unit of kg or Nm 3 ;

[0221] is the th type of fossil fuel carbon emission factor, with the unit of kg CO2 eq / kg or kg CO2 eq / Nm 3 ;

[0222] is the mass of the th type of chemical consumed in the sulfuric acid concentration process, with the unit of kg;

[0223] is the th type of chemical cradle-to-gate carbon emission factor, with the unit of kg CO2 eq / kg.

[0224] The concentrated sulfuric acid can be recycled back to the reaction process, saving the amount of new sulfuric acid. The sulfuric acid recycling carbon performance calculation formula is:

[0225] (3c)

[0226] In the formula:

[0227] is the carbon performance of sulfuric acid recycling in the th sulfuric acid concentration cycle subsystem, with the unit of kg CO2 eq;

[0228] is the mass of the recycled sulfuric acid, with the unit of kg;

[0229] is the cradle-to-gate carbon emission factor of sulfuric acid, with the unit of kg CO2 eq / kg.

[0230] ③ Sulfuric acid co-utilization subsystem

[0231] The calculation formula for the carbon emissions of the sulfuric acid co-utilization subsystem is:

[0232] (4)

[0233] Wherein:

[0234] is the carbon emission of the th sulfuric acid co - utilization subsystem, in kg CO2 eq;

[0235] is the carbon emission during the preparation of sulfuric acid required for the reaction process in the th sulfuric acid co - utilization subsystem, in kg CO2 eq;

[0236] is the carbon emission generated during the purification process of the th sulfuric acid co - utilization subsystem, in kg CO2 eq;

[0237] is the carbon performance of sulfuric acid co - utilization in the th sulfuric acid co - utilization subsystem, in kg CO2eq.

[0238] The sulfuric acid co - utilization subsystem involves two different reaction processes. Each reaction process requires a certain amount of sulfuric acid, and carbon emissions are generated during the preparation of this sulfuric acid. The calculation formula is:

[0239] (4a)

[0240] Wherein:

[0241] is the carbon emission during the preparation of sulfuric acid required in the th sulfuric acid co - utilization subsystem, in kgCO2 eq;

[0242] is the mass of fresh sulfuric acid required for the first reaction process in the th sulfuric acid co - utilization subsystem, in kg;

[0243] is the mass of fresh sulfuric acid required for the second reaction process in the th sulfuric acid co - utilization subsystem, in kg;

[0244] is the carbon emission factor of sulfuric acid from cradle to gate, in kg CO2 eq / kg.

[0245] In the sulfuric acid co-utilization subsystem, the sulfuric acid produced after the first reaction process needs to be purified to remove impurities therein to avoid interference of these impurities with the second reaction process and the quality of the products. The calculation formula for the carbon emissions in the purification process of the sulfuric acid co-utilization subsystem is:

[0246] (4b)

[0247] Where:

[0248] is the carbon emissions generated in the purification process of the th sulfuric acid co-utilization subsystem, with the unit of kg CO2eq;

[0249] is the amount of electricity consumed in the sulfuric acid purification process, with the unit of kW·h;

[0250] is the carbon emission factor of electricity, with the unit of kg CO2 eq / kW·h;

[0251] is the amount of the th type of fossil energy consumed, with the unit of kg or Nm 3 ;

[0252] is the th type of fossil energy's carbon emission factor, with the unit of kg CO2 eq / kg or kg CO2 eq / Nm 3 ;

[0253] is the th sulfuric acid co-utilization subsystem's mass of the th type of chemical reagent consumed in the purification process, with the unit of kg;

[0254] is the th type of chemical reagent's cradle-to-gate carbon emission factor, with the unit of kg CO2 eq / kg.

[0255] After the sulfuric acid produced in the first reaction process is purified, it can enter the second reaction process, replacing part of the new sulfuric acid in the second reaction process, thereby reducing the use of new sulfuric acid and the carbon emissions generated in its preparation process, and thus generating carbon emission reduction performance. The calculation formula for the sulfuric acid co-utilization carbon performance is:

[0256] (4c)

[0257] Where:

[0258] is the The carbon performance of sulfuric acid co-utilization in the sulfuric acid co-utilization subsystem, in kg CO2eq;

[0259] is the amount of new sulfuric acid saved through co-utilization in the

[0260] th sulfuric acid co-utilization subsystem, in kg;

[0261] The calculation formula for the amount of new sulfuric acid saved through co-utilization is:

[0262] (4c-1)

[0263] In the formula:

[0264] is the amount of new sulfuric acid saved through co-utilization in the

[0265] th sulfuric acid co-utilization subsystem, in kg; is the mass fraction of sulfuric acid entering the next reaction process after purification in the

[0266] th sulfuric acid co-utilization subsystem, in %; is the mass fraction of new sulfuric acid used in the

[0267] th sulfuric acid co-utilization subsystem, in %, and the mass fraction is usually 98%; is the mass of sulfuric acid entering the next reaction process after purification in the

[0268] ④ Acid-containing wastewater treatment subsystem

[0269] The calculation formula for the carbon emissions of the acid-containing wastewater treatment subsystem is:

[0270] (5)

[0271] In the formula:

[0272] is the carbon emissions of the

[0273] th acid-containing wastewater treatment subsystem, in kg CO2 eq; Carbon emissions during the neutralization of acidic wastewater in the acidic wastewater treatment subsystem, in kgCO2 eq;

[0274] is the carbon emissions during the purification process in the acidic wastewater treatment subsystem, in kg CO2 eq;

[0275] is the carbon emissions during the concentration and crystallization process in the acidic wastewater treatment subsystem, in kg CO2eq;

[0276] is the carbon performance of by - product sulfates in the acidic wastewater treatment subsystem, in kg CO2 eq.

[0277] The calculation formula for the carbon emissions during the neutralization of acidic wastewater is:

[0278] (5a)

[0279] In the formula:

[0280] is the carbon emissions during the neutralization of acidic wastewater in the acidic wastewater treatment subsystem, in kgCO2 eq;

[0281] is the amount of steam consumed during the neutralization of acidic wastewater, in MJ;

[0282] is the carbon emission factor of steam, in kg CO2 eq / MJ;

[0283] is the amount of electricity consumed during the neutralization of acidic wastewater, in kW·h;

[0284] is the carbon emission factor of electricity, in kg CO2 eq / kW·h;

[0285] is the mass of the th chemical reagent consumed during the neutralization of acidic wastewater, in kg;

[0286] is the carbon emission factor from cradle - to - gate of the th chemical reagent, in kg CO2 eq / kg.

[0287] After neutralization, the wastewater needs to be purified, for example, by means of activated carbon adsorption, membrane filtration, etc., to remove impurities in the wastewater and improve the purity of sulfate, thus laying a foundation for the recovery of sulfate. The carbon emissions of this process include the carbon emissions generated by the electricity, fossil energy, and chemical reagents used in the purification process. The calculation formula is:

[0288] (5b)

[0289] In the formula:

[0290] is the carbon emission of the purification process in the th acid-containing wastewater treatment subsystem, with the unit of kg CO2 eq;

[0291] is the amount of electricity consumed in the purification process of acid-containing wastewater, with the unit of kW·h;

[0292] is the carbon emission factor of electricity, with the unit of kg CO2 eq / kW·h;

[0293] is the amount of the th fossil energy consumed in the purification process of acid-containing wastewater. When the consumed fossil energy is coal, the unit is kg; when the consumed fossil energy is natural gas, the unit is Nm 3 ;

[0294] is the th carbon emission factor of fossil energy, with the unit of kg CO2 eq / kg or kg CO2 eq / Nm 3 ;

[0295] is the mass of the th chemical reagent consumed in the purification process of acid-containing wastewater, with the unit of kg;

[0296] is the th cradle-to-gate carbon emission factor of chemical reagent, with the unit of kg CO2 eq / kg.

[0297] After purification, the purity of sulfate in the wastewater is relatively high. At this time, it is necessary to extract the sulfate in the wastewater in solid form through concentration and crystallization, so as to ultimately achieve the efficient resource symbiotic utilization of sulfuric acid as a by-product. This process can be carried out through processes such as mechanical vapor recompression (MVR) and multi-effect evaporation. These processes all require the consumption of energy such as electricity and steam, and some processes also require the consumption of fossil fuels such as coal or natural gas. The carbon emissions in the process of concentrating and crystallizing the acid-containing wastewater come from the consumed steam, electricity, and fossil fuels. The carbon emission calculation formula is:

[0298] (5c)

[0299] Where:

[0300] is the carbon emission of the concentration and crystallization process in the th acid-containing wastewater treatment subsystem, in kg CO2eq;

[0301] is the amount of steam consumed in the process of concentrating and crystallizing the acid-containing wastewater, in MJ;

[0302] is the carbon emission factor of steam, in kg CO2 eq / MJ;

[0303] is the amount of electricity consumed in the process of concentrating and crystallizing the acid-containing wastewater, in kW·h;

[0304] is the carbon emission factor of electricity, in kg CO2 eq / kW·h;

[0305] is the amount of the th fossil fuel consumed in the process of concentrating and crystallizing the acid-containing wastewater. When the consumed fossil fuel is coal, the unit is kg; when the consumed fossil fuel is natural gas, the unit is Nm 3 ;

[0306] is the th carbon emission factor of fossil fuel, in kg CO2 eq / kg or kg CO2 eq / Nm 3 .

[0307] After concentration and crystallization, the acid-containing wastewater treatment subsystem can recover by-product sulfates. These sulfates can be used as raw materials in other chemical reaction processes and put into production to replace the sulfates prepared by other processes. Thus, a certain amount of carbon emission reduction performance can be generated. The calculation formula is:

[0308] (5d)

[0309] In the formula:

[0310] is the carbon performance of by - product sulfate in the th acid - containing wastewater treatment subsystem, with the unit of kg CO2 eq;

[0311] is the th mass of by - product sulfate in the acid - containing wastewater treatment subsystem, with the unit of kg;

[0312] is the cradle - to - gate carbon emission factor of this sulfate, with the unit of kg CO2 eq / kg.

[0313] In the actual product system, the sulfuric acid recycling and symbiotic utilization system may simultaneously include multiple different sulfuric acid usage subsystems, sulfuric acid concentration and recycling subsystems, sulfuric acid symbiotic utilization subsystems, and acid - containing wastewater treatment subsystems. Therefore, after calculating the carbon footprint of each subsystem separately, the subsystems need to be combined according to the actual production process system. When combining, the types and quantities of products of each subsystem need to be consistent with the actual working conditions, and the corresponding carbon footprints of each subsystem are converted, and finally summed up to obtain the carbon footprint of the entire sulfuric acid recycling and symbiotic system.

[0314] The carbon footprint calculation formula of the sulfuric acid recycling and symbiotic utilization system is:

[0315] (1)

[0316] In the formula:

[0317] is the carbon footprint of the sulfuric acid recycling and symbiotic utilization system, with the unit of kg CO2 eq;

[0318] is the th carbon emission of the sulfuric acid usage subsystem, with the unit of kg CO2 eq;

[0319] is the th carbon emission of the sulfuric acid concentration and recycling subsystem, with the unit of kg CO2 eq;

[0320] is the th carbon emission of the sulfuric acid symbiotic utilization subsystem, with the unit of kg CO2 eq;

[0321] is the th carbon emission of the acid - containing wastewater treatment subsystem, with the unit of kg CO2 eq.

[0322] Example 2

[0323] Taking the circular symbiotic utilization of sulfuric acid in dye and intermediate products as an example, this embodiment fully illustrates a method for quantitatively evaluating the full-life cycle carbon footprint of a sulfuric acid circular symbiotic utilization system provided by the present invention in combination with actual statistical experimental data. The boundary of the sulfuric acid full-life cycle system for this dye intermediate product is as Figure 3 shown.

[0324] The boundary of this system is the full life cycle from sulfuric acid production to sulfuric acid use and then to final treatment and disposal, including three reaction processes: benzene nitration, reductant nitration, and diamine hydrolysis.

[0325] In the basic production system, that is, in the case where no measures for sulfuric acid recycling and symbiotic utilization are taken, according to the reaction process, this system can be divided into three sulfuric acid use subsystems and three corresponding acid-containing wastewater disposal subsystems. After sulfuric acid preparation is completed, it enters reaction processes such as benzene nitration, dye diazo coupling, reductant nitration, and m-phenylenediamine hydrolysis respectively, and then acid-containing wastewater with different concentrations is generated. Then, resource disposal and utilization of the wastewater are realized through neutralization, purification, and concentration crystallization. By separately collecting the consumption of sulfuric acid in each sulfuric acid use subsystem and the consumption of energy and chemical reagents in the acid-containing wastewater disposal subsystem, the carbon footprint of this system can be calculated.

[0326] As Figure 3 , in the basic production system:

[0327] I. Sulfuric acid use subsystem

[0328] The sulfuric acid use data is shown in Table 1.

[0329] Table 1 List of emission activity data for the sulfuric acid use subsystem

[0330]

[0331] The carbon emissions of the sulfuric acid use subsystem originate from the carbon emissions generated during the sulfuric acid preparation process, and the calculation formula is:

[0332] (2a)

[0333] In the formula:

[0334] is the carbon emission of the sulfuric acid use subsystem, with the unit of kg CO2 eq;

[0335] is the th mass of new sulfuric acid used in the sulfuric acid use subsystem, with the unit of kg;

[0336] is the The mass concentration of the new sulfuric acid used in the sulfuric acid usage subsystem;

[0337] is the carbon emission factor of sulfuric acid from cradle to gate, with the unit of kg CO2 eq / kg.

[0338] The calculation process is as follows:

[0339]

[0340] Using the data in Table 1, the carbon footprint of the sulfuric acid usage subsystem is calculated to be 3293.63 kg CO2 eq.

[0341] II. Acid-containing wastewater treatment subsystem

[0342] The activity data of the emission sources in the acid-containing wastewater treatment subsystem are shown in Table 2.

[0343] Table 2 Activity data of the emission sources in the acid-containing wastewater treatment subsystem

[0344]

[0345] The calculation formula for the carbon emissions in the neutralization process of acid-containing wastewater is:

[0346] (5a - 1)

[0347] In the formula:

[0348] is the carbon emission in the neutralization process of the th acid-containing wastewater treatment subsystem, with the unit of kgCO2 eq;

[0349] is the amount of electricity consumed in the neutralization process of acid-containing wastewater, with the unit of kW·h;

[0350] is the carbon emission factor of electricity, with the unit of kg CO2 eq / kW·h;

[0351] is the mass of the th chemical reagent consumed in the neutralization process of acid-containing wastewater, with the unit of kg;

[0352] is the th carbon emission factor of the chemical reagent from cradle to gate, with the unit of kg CO2 eq / kg.

[0353] The calculation process is as follows:

[0354]

[0355] The carbon emission calculation formula for the wastewater purification process is as follows:

[0356] (5b)

[0357] In the formula:

[0358] is the carbon emission during the purification process in the th acidic wastewater treatment subsystem, with the unit of kg CO2 eq;

[0359] is the amount of electricity consumed during the purification process of acidic wastewater, with the unit of kW·h;

[0360] is the carbon emission factor of electricity, with the unit of kg CO2 eq / kW·h;

[0361] is the amount of the th type of fossil energy consumed during the purification process of acidic wastewater. When the consumed fossil energy is coal, the unit is kg; when the consumed fossil energy is natural gas, the unit is Nm 3 ;

[0362] is the th carbon emission factor of fossil energy, with the unit of kg CO2 eq / kg or kg CO2 eq / Nm 3 ;

[0363] is the mass of the th type of chemical reagent consumed during the purification process of acidic wastewater, with the unit of kg;

[0364] is the th cradle-to-gate carbon emission factor of chemical reagent, with the unit of kg CO2 eq / kg.

[0365] The calculation process is as follows:

[0366]

[0367] After purification, the sulfate in the wastewater is extracted in solid form through concentration and crystallization. The carbon emission calculation formula for this process is:

[0368] (5c-1)

[0369] In the formula:

[0370] is the Carbon emissions during the concentration and crystallization process in the acid-containing wastewater treatment subsystem, in kg CO2eq;

[0371] is the amount of steam consumed during the concentration and crystallization process of acid-containing wastewater, in kg;

[0372] is the carbon emission factor of steam, in kg CO2 eq / kg;

[0373] is the amount of electricity consumed during the concentration and crystallization process of acid-containing wastewater, in kW·h;

[0374] is the carbon emission factor of electricity, in kg CO2 eq / kW·h.

[0375] The calculation process is as follows:

[0376]

[0377] After concentration and crystallization, the acid-containing wastewater treatment subsystem can recover by-product sulfates, which can be used as raw materials in other chemical reaction processes and replace sulfates prepared by other processes, thus generating a certain amount of carbon emission reduction performance. The calculation formula is:

[0378] (5d)

[0379] In the formula:

[0380] is the carbon performance of by-product sulfates in the th acid-containing wastewater treatment subsystem, in kg CO2 eq;

[0381] is the th acid-containing wastewater treatment subsystem, in kg;

[0382] is the cradle-to-gate carbon emission factor of this sulfate, in kg CO2 eq / kg.

[0383] The calculation process is as follows:

[0384]

[0385] The carbon emission calculation formula for the acid-containing wastewater treatment subsystem is:

[0386] (5)

[0387] In the formula:

[0388] is the carbon emission of the th acidic wastewater treatment subsystem, in kg CO2 eq;

[0389] is the carbon emission during the neutralization of acidic wastewater in the th acidic wastewater treatment subsystem, in kgCO2 eq;

[0390] is the carbon emission during the purification process in the th acidic wastewater treatment subsystem, in kg CO2 eq;

[0391] is the carbon emission during the concentration and crystallization process in the th acidic wastewater treatment subsystem, in kg CO2eq;

[0392] is the carbon performance of by - product sulfate in the th acidic wastewater treatment subsystem, in kg CO2 eq.

[0393] The calculation process is as follows:

[0394]

[0395] III. Summary of the Carbon Footprint of Sulfuric Acid in the Basic Production System throughout its Life Cycle

[0396] The formula for calculating the carbon footprint of sulfuric acid in the basic production system throughout its life cycle is:

[0397] (1a)

[0398] In the formula:

[0399] is the carbon footprint of sulfuric acid in the basic production system throughout its life cycle, in kg CO2 eq;

[0400] is the carbon emission of the th sulfuric acid - using subsystem, in kg CO2 eq;

[0401] is the carbon emission of the th acidic wastewater treatment subsystem, in kg CO2 eq.

[0402] The calculation process is as follows:

[0403]

[0404] After the above production process, the product data of the basic production system is shown in Table 3.

[0405] Table 3 Product Data of Basic Production System

[0406]

[0407] The calculation results show that when producing the product portfolio shown in Table 3, the sulfuric acid carbon footprint of the basic production system is 37,259.66 kg CO2 eq. Among them, the carbon footprints of the three sulfuric acid usage subsystems corresponding to benzene nitration, nitro reduction, and diamine hydrolysis account for 2.73%, 2.60%, and 3.51% of the carbon footprint of the entire system respectively. The carbon emission of the acid-containing wastewater treatment subsystem is 33,966.02 kg CO2 eq, and the carbon performance brought by the recovery of by-product ammonium sulfate is 24,240.18 kg CO2 eq. The disposal of acid-containing wastewater is an important source of carbon emissions. By resourcefully disposing and utilizing it and by-producing ammonium sulfate, its carbon emissions can be effectively reduced.

[0408] Based on the basic production system, the transformation of sulfuric acid recycling and symbiotic utilization is implemented to form a sulfuric acid recycling and symbiotic utilization system. In this system, after sulfuric acid is prepared, it enters the benzene nitration process. The acid-containing wastewater with a sulfuric acid concentration of 69% generated after the reaction is concentrated. One part is concentrated to sulfuric acid with a concentration of 98% and then recycled to the benzene nitration process, forming a sulfuric acid concentration recycling subsystem in this system. The other part is concentrated to sulfuric acid with a concentration of 93% and then used as a raw material in the nitro reduction process to prepare nitro reductant. After the reaction is completed, it becomes acid-containing wastewater with a sulfuric acid concentration of 28%. The third part can enter the diazo coupling process of dyes. After the reaction is completed, it becomes wastewater with a sulfuric acid concentration of 5%. Thus, the first sulfuric acid symbiotic utilization subsystem in this system is formed. After the acid-containing wastewater with a sulfuric acid concentration of 28% is purified by sulfuric acid, it is again used as a raw material in the diamine hydrolysis process to produce hydroquinone. After the reaction is completed, it becomes acid-containing wastewater with a sulfuric acid concentration of 6%. Thus, the second sulfuric acid symbiotic utilization subsystem in this system is formed. Finally, the acid-containing wastewater with sulfuric acid concentrations of 5% and 6% is resourcefully disposed and utilized through neutralization, purification, and concentrated crystallization, and by-produces ammonium sulfate. This sulfuric acid recycling and symbiotic utilization system includes a sulfuric acid concentration recycling subsystem, two sulfuric acid symbiotic utilization subsystems, and an acid-containing wastewater treatment subsystem. Collect the material and energy consumption of each link in each subsystem and calculate its carbon footprint. After establishing the full-life cycle carbon emission model of the sulfuric acid recycling and symbiotic utilization system, set different recycling and symbiotic utilization scenarios, formulate a carbon footprint optimization plan, and determine the mass of sulfuric acid with different concentrations distributed to different utilization routes, then the carbon footprint of the entire system under the comprehensive optimization scenario of carbon reduction and pollution reduction can be calculated.

[0409] In the calculation, production data when using the sulfuric acid cycle symbiotic utilization system to produce the product combination shown in Table 3 are used. First, calculate the change in carbon footprint (including carbon performance and increase in carbon footprint) of the sulfuric acid cycle symbiotic utilization system relative to the basic production system and the carbon footprint of the sulfuric acid-containing wastewater treatment process in the sulfuric acid cycle symbiotic utilization system. Then, integrate the results with the carbon footprint calculation results of the basic production system to obtain the carbon footprint calculation result of the sulfuric acid cycle symbiotic utilization system.

[0410] As Figure 3 , in the sulfuric acid cycle symbiotic utilization system:

[0411] I. Sulfuric acid usage subsystem

[0412] The sulfuric acid usage subsystem uses the recycled symbiotic sulfuric acid data as shown in Table 4.

[0413] Table 4 Recycled symbiotic sulfuric acid data used by the sulfuric acid usage subsystem

[0414]

[0415] The carbon performance calculation formula for the sulfuric acid usage subsystem using recycled symbiotic sulfuric acid is:

[0416] (3c - 1)

[0417] In the formula:

[0418] is the carbon performance of the sulfuric acid cycle symbiotic process, with the unit of kg CO2 eq;

[0419] is the th mass of the recycled symbiotic sulfuric acid used by the sulfuric acid usage subsystem, with the unit of kg;

[0420] is the carbon emission factor of sulfuric acid from cradle to gate, with the unit of kg CO2 eq / kg.

[0421] The calculation process is as follows:

[0422]

[0423] Based on the data in Table 4, the carbon emission reduction performance of the sulfuric acid cycle symbiotic process is calculated to be 2364.61 kg CO2 eq.

[0424] II. Sulfuric acid concentration subsystem

[0425] The emission source data for the sulfuric acid concentration process are shown in Table 5.

[0426] Table 5 Emission source data for the sulfuric acid concentration process

[0427]

[0428] The calculation formula for the emissions during the sulfuric acid concentration process is as follows:

[0429] (3b - 1)

[0430] In the formula:

[0431] is the carbon emission of the sulfuric acid concentration process in the th sulfuric acid concentration cycle subsystem, with the unit of kg CO2eq;

[0432] is the amount of steam consumed in the sulfuric acid concentration process, with the unit of kg;

[0433] is the carbon emission factor of steam, with the unit of kg CO2 eq / kg;

[0434] is the amount of electricity consumed in the sulfuric acid concentration process, with the unit of kW·h;

[0435] is the carbon emission factor of electricity, with the unit of kg CO2 eq / kW·h;

[0436] is the mass of the th chemical consumed in the sulfuric acid concentration process, with the unit of kg;

[0437] is the th cradle-to-gate carbon emission factor of the chemical, with the unit of kg CO2 eq / kg.

[0438] The calculation process is as follows:

[0439]

[0440] III. Sulfuric acid purification subsystem

[0441] The data of the sulfuric acid purification process is shown in Table 6.

[0442] Table 6 Data of sulfuric acid purification process

[0443]

[0444] The calculation formula for the carbon emissions of the sulfuric acid co-utilization subsystem purification process is:

[0445] (4b)

[0446] In the formula:

[0447] is the carbon emissions generated during the purification process of the th sulfuric acid co-utilization subsystem, with the unit of kg CO2eq;

[0448] is the amount of electricity consumed during the sulfuric acid purification process, with the unit of kW·h;

[0449] is the carbon emission factor of electricity, with the unit of kg CO2 eq / kW·h;

[0450] is the amount of the th fossil fuel consumed, with the unit of kg or Nm 3 ;

[0451] is the th carbon emission factor of fossil fuel, with the unit of kg CO2 eq / kg or kg CO2 eq / Nm 3 ;

[0452] is the th sulfuric acid co-utilization subsystem's consumption of the th chemical reagent's mass, with the unit of kg;

[0453] is the th chemical reagent's cradle-to-gate carbon emission factor, with the unit of kg CO2 eq / kg.

[0454] The calculation process is as follows:

[0455]

[0456] IV. Acid-containing wastewater treatment subsystem

[0457] The process emission source activity data of the acid-containing wastewater treatment subsystem is shown in Table 7.

[0458] Table 7 Process emission source activity data of the acid-containing wastewater treatment subsystem

[0459]

[0460] The carbon emissions calculation formula for the acid-containing wastewater neutralization process is:

[0461] (5a-1)

[0462] In the formula:

[0463] is the carbon emission during the neutralization process of acidic wastewater in the th acidic wastewater treatment subsystem, with the unit of kgCO2 eq;

[0464] is the amount of electricity consumed during the neutralization process of acidic wastewater, with the unit of kW·h;

[0465] is the carbon emission factor of electricity, with the unit of kg CO2 eq / kW·h;

[0466] is the mass of the th chemical reagent consumed during the neutralization process of acidic wastewater, with the unit of kg;

[0467] is the th cradle-to-gate carbon emission factor of the chemical reagent, with the unit of kg CO2 eq / kg.

[0468] The calculation process is as follows:

[0469]

[0470] The carbon emission calculation formula for the wastewater purification process is:

[0471] (5b)

[0472] In the formula:

[0473] is the carbon emission during the purification process in the th acidic wastewater treatment subsystem, with the unit of kg CO2 eq;

[0474] is the amount of electricity consumed during the purification process of acidic wastewater, with the unit of kW·h;

[0475] is the carbon emission factor of electricity, with the unit of kg CO2 eq / kW·h;

[0476] is the amount of the th fossil energy consumed during the purification process of acidic wastewater. When the consumed fossil energy is coal, the unit is kg; when the consumed fossil energy is natural gas, the unit is Nm 3 ;

[0477] is the th carbon emission factor of fossil energy, with the unit of kg CO2 eq / kg or kg CO2 eq / Nm 3 ;

[0478] is the mass of the th chemical reagent consumed in the purification process of acid-containing wastewater, with the unit of kg;

[0479] is the th carbon emission factor of the chemical reagent from cradle to gate, with the unit of kg CO2 eq / kg.

[0480] The calculation process is as follows:

[0481]

[0482] After purification, the sulfate in the wastewater is extracted in solid form through concentration and crystallization. The carbon emission calculation formula for this process is:

[0483] (5c - 1)

[0484] In the formula:

[0485] is the carbon emission of the concentration and crystallization process in the th acid-containing wastewater treatment subsystem, with the unit of kg CO2eq;

[0486] is the amount of steam consumed in the concentration and crystallization process of acid-containing wastewater, with the unit of kg;

[0487] is the carbon emission factor of steam, with the unit of kg CO2 eq / kg;

[0488] is the amount of electricity consumed in the concentration and crystallization process of acid-containing wastewater, with the unit of kW·h;

[0489] is the carbon emission factor of electricity, with the unit of kg CO2 eq / kW·h.

[0490] The calculation process is as follows:

[0491]

[0492] After concentration and crystallization, the acid-containing wastewater treatment subsystem can recover by-product sulfate, which can be used as raw materials in other chemical reaction processes and replace the sulfate prepared by other processes, thus generating a certain amount of carbon emission reduction performance. The calculation formula is:

[0493] (5d)

[0494] In the formula:

[0495] is the carbon performance of by - product sulfate in the th acid - containing wastewater treatment subsystem, in kg CO2 eq;

[0496] is the th mass of by - product sulfate in the acid - containing wastewater treatment subsystem, in kg;

[0497] is the cradle - to - gate carbon emission factor of this sulfate, in kg CO2 eq / kg.

[0498] The calculation process is as follows:

[0499]

[0500] The carbon emission calculation formula for the acid - containing wastewater treatment subsystem is:

[0501] (5)

[0502] In the formula:

[0503] is the th carbon emission of the acid - containing wastewater treatment subsystem, in kg CO2 eq;

[0504] is the th carbon emission in the neutralization process of acid - containing wastewater in the acid - containing wastewater treatment subsystem, in kgCO2 eq;

[0505] is the th carbon emission in the purification process of the acid - containing wastewater treatment subsystem, in kg CO2 eq;

[0506] is the th carbon emission in the concentration and crystallization process of the acid - containing wastewater treatment subsystem, in kg CO2eq;

[0507] is the th carbon performance of by - product sulfate in the acid - containing wastewater treatment subsystem, in kg CO2 eq.

[0508] The calculation process is as follows:

[0509]

[0510] The formula for the life - cycle carbon footprint of the sulfuric acid cycle symbiotic utilization system is:

[0511] (1b)

[0512] Wherein:

[0513] is the life cycle carbon footprint of the sulfuric acid recycling and symbiotic utilization system, with the unit of kg CO2 eq;

[0514] is the carbon emission of the th sulfuric acid usage subsystem of the basic production system, with the unit of kg CO2 eq;

[0515] is the carbon performance of using recycled and symbiotic sulfuric acid in the sulfuric acid usage subsystem, with the unit of kg CO2 eq;

[0516] is the th carbon emission of the sulfuric acid concentration and treatment subsystem, with the unit of kg CO2 eq;

[0517] is the th carbon emission of the sulfuric acid purification and treatment subsystem, with the unit of kg CO2 eq;

[0518] is the th carbon emission of the acid-containing wastewater disposal subsystem, with the unit of kg CO2 eq.

[0519] The calculation process is as follows:

[0520]

[0521] The calculation result of the life cycle carbon footprint of the sulfuric acid recycling and symbiotic utilization system is as Figure 4 shown. When producing the product combination shown in Table 3, the life cycle carbon footprint of the sulfuric acid recycling and symbiotic utilization system is reduced by 19459.24 kg CO2 eq compared with the basic production system. Among them, the sulfuric acid concentration subsystem generates an additional 3230.48 kg CO2 eq of carbon emission during the sulfuric acid concentration and disposal process, and the purification treatment of sulfuric acid generates an additional 1674.82 kg CO2 eq of carbon emission, but a carbon performance of 2364.61 kg CO2 eq is achieved through the recycling and symbiosis of sulfuric acid; due to the reduction in the generation and treatment amount of acid-containing wastewater, the carbon emission of the acid-containing wastewater disposal subsystem is reduced by 21999.94 kg CO2 eq compared with the basic production system.

[0522] The results show that for the carbon emissions generated during the preparation of sulfuric acid required for the reaction process, the sulfuric acid use system can be transformed for circular symbiotic utilization. By replacing new sulfuric acid with recycled and symbiotically utilized sulfuric acid, the utilization efficiency of sulfuric acid can be effectively improved, the generation amount of acid-containing wastewater can be significantly reduced, and thus the life-cycle carbon footprint of sulfuric acid can be more effectively reduced.

[0523] Example 3

[0524] This example is a device for quantitatively evaluating the life-cycle carbon footprint of a sulfuric acid circular symbiotic utilization system, as Figure 5 shown. The device includes a memory and one or more processors. The memory stores executable code that can input the life-cycle operation data of the sulfuric acid circular symbiotic utilization system. When the one or more processors execute the executable code, they are used to implement the method for quantitatively evaluating and optimizing the life-cycle carbon footprint of the sulfuric acid circular symbiotic utilization system in Example 1 or Example 2, and output the results of quantitatively evaluating and optimizing the life-cycle carbon footprint of the sulfuric acid circular symbiotic utilization system.

[0525] The content described in the embodiments of this specification is only a list of the implementation forms of the inventive concept. The protection scope of the present invention should not be regarded as limited to the specific forms stated in the embodiments. The protection scope of the present invention also extends to equivalent technical means that can be conceived by those skilled in the art based on the inventive concept of the present invention.

Claims

1. A method for quantitatively evaluating the carbon footprint of the entire life cycle of a sulfuric acid recycling and symbiotic utilization system, comprising the following steps: 1) Divide subsystems in the entire life cycle of the sulfuric acid recycling and symbiotic utilization system and determine the system boundary for quantitatively evaluating the carbon footprint; 2) Determine the carbon emission sources of sulfuric acid in each subsystem according to the production process and construct a carbon emission inventory; 3) Determine the carbon emission calculation methods for each emission source and construct a carbon footprint quantitative evaluation model; 4) Establish the activity data and carbon emission factors for each carbon emission source and calculate the carbon footprint of the sulfuric acid recycling and symbiotic utilization system.

2. The method according to claim 1, characterized in that, The boundary of the sulfuric acid recycling and symbiotic utilization system described in step 1) is all processes from the production of sulfuric acid to the treatment and disposal of acid-containing wastewater, including four types of subsystems: ① sulfuric acid use subsystem, ② sulfuric acid concentration and recycling subsystem, ③ sulfuric acid symbiotic utilization subsystem, ④ acid-containing wastewater disposal subsystem; The carbon footprint calculation formula of the sulfuric acid recycling and symbiotic utilization system is: （1） Where: is the carbon footprint of the sulfuric acid recycling symbiotic utilization system, with the unit of kg CO2 eq; is the carbon emission of the th sulfuric acid usage subsystem, in kg CO2 eq; is the carbon emission of the th sulfuric acid concentration recycling subsystem, in kg CO2 eq; is the carbon emission of the th sulfuric acid co-utilization subsystem, in kg CO2 eq; is the carbon emission of the th acid-containing wastewater treatment subsystem, in kg CO2 eq.

3. The method according to claim 2, characterized in that, The sulfuric acid use subsystem described includes: after sulfuric acid preparation, it participates in a reaction process, and the dilute sulfuric acid generated after the reaction enters the subsequent treatment and disposal process in the form of acid-containing wastewater; The carbon emission sources of the sulfuric acid use subsystem include: carbon emissions generated during the sulfuric acid preparation process and carbon emissions generated during the disposal of acid-containing wastewater; The carbon emission calculation formula of the sulfuric acid use subsystem is: （2） Where: is the carbon emission of the th sulfuric acid usage subsystem, in kg CO2 eq; is the mass of the new sulfuric acid used in the th sulfuric acid usage subsystem, in kg; is the cradle-to-gate carbon emission factor of sulfuric acid, with the unit of kg CO2 eq / kg; The carbon emission calculation for the disposal of acid-containing wastewater refers to the acid-containing wastewater disposal subsystem in ④.

4. The method according to claim 2, characterized in that The sulfuric acid concentration and recycling subsystem is: after sulfuric acid preparation, it participates in a reaction process, and the sulfuric acid after the reaction is concentrated and then recycled back to the previous reaction process; The carbon emission sources of the sulfuric acid concentration and recycling subsystem include: carbon emissions generated during the sulfuric acid preparation process, carbon emissions generated by the energy consumed during the sulfuric acid concentration process, and carbon emissions generated by the sulfur trioxide chemical reagent added in some concentration processes, carbon emissions generated during the disposal of some acid-containing wastewater after sulfuric acid recycling, and the carbon performance brought about by replacing part of the new sulfuric acid after sulfuric acid recycling; The carbon emission calculation formula of the sulfuric acid concentration and recycling subsystem is: （3） Where: is the carbon emission of the th sulfuric acid concentration recycling subsystem, in kg CO2 eq; is the carbon emissions during the preparation of sulfuric acid required in the th sulfuric acid concentration recycling subsystem, with the unit of kg CO2eq; For the carbon emissions from sulfuric acid concentration treatment in the th sulfuric acid concentration cycle subsystem, in kg CO2 eq; For the carbon performance of sulfuric acid circulation in the th sulfuric acid concentration circulation subsystem, in kg CO2 eq; The carbon emission calculation formula for the sulfuric acid required in the reaction process during the preparation process is: （3a） Where: is the carbon emission during the preparation of sulfuric acid required for the reaction process in the th sulfuric acid concentration recycling subsystem, with the unit of kg CO2 eq / kg; is the mass of fresh sulfuric acid required for the reaction process in the th sulfuric acid concentration recycle subsystem, with the unit of kg; is the cradle-to-gate carbon emission factor of sulfuric acid, with the unit of kg CO2 eq / kg; The calculation formula for the emissions during the sulfuric acid concentration process is: （3b） Where: is the carbon emission during the sulfuric acid concentration process in the th sulfuric acid concentration cycle subsystem, with the unit of kg CO2 eq / kg; is the amount of steam consumed in the sulfuric acid concentration process, in MJ; is the carbon emission factor of steam, with the unit of kg CO2 eq / MJ; is the electricity consumed in the sulfuric acid concentration process, in kW·h; is the carbon emission factor of electricity, with the unit of kg CO2 eq / kW·h; some sulfuric acid concentration processes use coal or natural gas fossil energy, is the amount of the th type of fossil energy consumed in this process, with the unit of kg or Nm 3 ; is the carbon emission factor of the th fossil energy, with the unit of kg CO2 eq / kg or kg CO2 eq / Nm 3 ; The mass of the th chemical consumed in the sulfuric acid concentration process, in kg; For the cradle-to-gate carbon emission factor of the nth chemical, in kg CO2 eq / kg; The calculation formula for the carbon performance of sulfuric acid recycling is: （3c） Where: is the carbon performance of sulfuric acid circulation in the th sulfuric acid concentration circulation subsystem, in kg CO2 eq; is the mass of recycled sulfuric acid, in kg; is the cradle-to-gate carbon emission factor of sulfuric acid, with the unit of kg CO2 eq / kg; The carbon emission calculation for the disposal of acid-containing wastewater generated by the sulfuric acid concentration and recycling subsystem refers to the acid-containing wastewater disposal subsystem in ④.

5. The method according to claim 2, wherein The sulfuric acid symbiotic utilization subsystem includes: after sulfuric acid preparation, it participates in a reaction process, and the sulfuric acid after the reaction is purified and then participates in another reaction process, forming a symbiotic relationship between two different reaction processes. After one or more layers of symbiosis, the sulfuric acid used enters the subsequent treatment and disposal process in the form of acid-containing wastewater; The carbon emission sources of the sulfuric acid symbiotic utilization subsystem include: carbon emissions generated during the sulfuric acid preparation process, carbon emissions generated during the preparation of the activated carbon, flocculant, and oxidant chemical reagents consumed during the sulfuric acid purification process, carbon emissions generated when the acid-containing wastewater enters the subsequent treatment and disposal process, and the carbon performance brought about by replacing part of the new sulfuric acid during sulfuric acid symbiosis; The carbon emission calculation formula of the sulfuric acid symbiotic utilization subsystem is: （4） Where: is the carbon emission of the th sulfuric acid co-utilization subsystem, in kg CO2 eq; is the carbon emission during the preparation of sulfuric acid required for the reaction process in the th sulfuric acid co-utilization subsystem, with the unit of kg CO2 eq; is the carbon emission generated by the th sulfuric acid co-utilization subsystem during the purification process, with the unit of kg CO2 eq; is the carbon performance of sulfuric acid co-utilization in the th sulfuric acid co-utilization subsystem, with the unit of kg CO2 eq; The carbon emission calculation formula for the preparation process of sulfuric acid required in the reaction process of the sulfuric acid co-utilization subsystem is as follows: （4a） Where: is the carbon emission during the preparation of sulfuric acid required in the th sulfuric acid co-utilization subsystem, with the unit of kg CO2eq; is the mass of the new sulfuric acid required for the first reaction process in the first sulfuric acid co-utilization subsystem, with the unit of kg; is the mass of the new sulfuric acid required for the second reaction process in the second sulfuric acid co-utilization subsystem, in kg; is the cradle-to-gate carbon emission factor of sulfuric acid, with the unit of kg CO2 eq / kg; The carbon emission calculation formula for the purification process of the sulfuric acid co-utilization subsystem is as follows: （4b） Where: is the carbon emission generated by the th sulfuric acid co-utilization subsystem during the purification process, with the unit of kg CO2 eq; is the amount of electricity consumed in the sulfuric acid purification process, in kW·h; is the carbon emission factor of electricity, with the unit of kg CO2 eq / kW·h; is the quantity of the th fossil energy consumed, with the unit of kg or Nm 3 ; For the carbon emission factor of the 3 th fossil energy, unit: kg CO2 eq / kg or kg CO2 eq / Nm is the mass of the th chemical reagent consumed in the purification process of the sulfuric acid co-utilization subsystem, with the unit of kg; is the carbon emission factor of the nth chemical reagent from cradle to gate, in kg CO2 eq / kg; The calculation formula for the sulfuric acid co-utilization carbon performance of the sulfuric acid co-utilization subsystem is as follows: （4c） Where: is the carbon performance of sulfuric acid co-utilization in the th sulfuric acid co-utilization subsystem, with the unit of kg CO2 eq; is the new amount of sulfuric acid saved through symbiotic utilization in the th symbiotic sulfuric acid utilization subsystem, with the unit of kg; is the cradle-to-gate carbon emission factor of sulfuric acid, with the unit of kg CO2 eq / kg; In the sulfuric acid co-utilization carbon performance, the calculation formula for the saved new sulfuric acid usage is as follows: （4c-1） Where: is the new amount of sulfuric acid saved through symbiotic utilization in the is the mass fraction of sulfuric acid entering the next reaction process after purification in the sulfuric acid co-utilization subsystem, with the unit of %; is the new sulfuric acid mass fraction used in the th sulfuric acid co-utilization subsystem, in %, and the mass fraction is usually 98%; is the mass of sulfuric acid that enters the next reaction process after purification in the th sulfuric acid co-utilization subsystem, with the unit of kg; The carbon emission calculation for the disposal of acid-containing wastewater generated by the sulfuric acid co-utilization subsystem refers to the acid-containing wastewater disposal subsystem in ④.

6. The method according to claim 2, wherein The acid-containing wastewater disposal subsystem includes: the acid-containing wastewater generated in each production link is combined and then converted into sulfates through neutralization, purification, and concentration crystallization to achieve harmlessness and resource utilization; The carbon emission sources of the acid-containing wastewater disposal subsystem include: carbon emissions generated during the neutralization process of acid-containing wastewater, carbon emissions during the purification process of acid-containing wastewater, carbon emissions during the concentration crystallization process of acid-containing wastewater, and the carbon performance of recovered by-product sulfates; The carbon emission calculation formula for the acid-containing wastewater disposal subsystem is as follows: （5） Where: is the carbon emission of the th acid-containing wastewater treatment subsystem, in kg CO2 eq; is the carbon emission during the neutralization process of acidic wastewater in the th acidic wastewater treatment subsystem, with the unit of kg CO2eq; is the carbon emission during the purification process in the th acid-containing wastewater treatment subsystem, in kg CO2 eq; is the carbon emission during the concentration and crystallization process of the acid-containing wastewater treatment subsystem, with the unit of kg CO2 eq; is the carbon performance of by - product sulfate in the th acid - containing wastewater treatment subsystem, with the unit of kg CO2 eq; The carbon emissions generated during the neutralization process of the acid-containing wastewater include: The carbon emissions during the neutralization process of acid-containing wastewater include the carbon emissions generated by the energy used and the carbon emissions generated during the preparation process of the added alkaline chemical reagents. The calculation formula is as follows: （5a） Where: is the carbon emission during the neutralization process of acidic wastewater in the th acidic wastewater treatment subsystem, with the unit of kg CO2eq; is the amount of steam consumed during the neutralization process of acid-containing wastewater, in MJ; is the carbon emission factor of steam, with the unit of kg CO2 eq / MJ; is the amount of electricity consumed in the neutralization process of acidic wastewater, in the unit of kW·h; is the carbon emission factor of electricity, with the unit of kg CO2 eq / kW·h; is the mass of the chemical reagent consumed in the neutralization process of the acidic wastewater, in kg; is the cradle-to-gate carbon emission factor of the th chemical reagent, with the unit of kg CO2 eq / kg; The carbon emissions during the purification process of acid-containing wastewater include the carbon emissions generated by the electricity, fossil energy, and chemical reagents used during the purification process. The calculation formula is as follows: （5b） Where: is the carbon emission during the purification process in the th acid-containing wastewater treatment subsystem, with the unit of kg CO2 eq; is the amount of electricity consumed in the purification process of acid-containing wastewater, in units of kW·h; is the carbon emission factor of electricity, with the unit of kg CO2 eq / kW·h; is the amount of the type of fossil energy consumed in the purification process of acid-containing wastewater. When the consumed fossil energy is coal, the unit is kg; when the consumed fossil energy is natural gas, the unit is Nm 3 ; is the carbon emission factor of the th fossil energy, with the unit of kg CO2 eq / kg or kg CO2 eq / Nm 3 ; is the mass of the chemical reagent consumed in the purification process of acid-containing wastewater, in kg; is the cradle-to-gate carbon emission factor of the th chemical reagent, with the unit of kg CO2 eq / kg; The carbon emissions during the concentration crystallization process of acid-containing wastewater include the carbon emissions generated by the electricity, steam, and fossil energy used during concentration crystallization. The calculation formula is as follows: （5c） Where: is the carbon emission during the concentration and crystallization process of the acid-containing wastewater treatment subsystem, in kg CO2 eq; is the amount of steam consumed during the concentration and crystallization process of acid-containing wastewater, with the unit of MJ; is the carbon emission factor of steam, with the unit of kg CO2 eq / MJ; is the amount of electricity consumed in the concentrated crystallization process of acid-containing wastewater, in the unit of kW·h; is the carbon emission factor of electricity, with the unit of kg CO2 eq / kW·h; is the amount of the type of fossil energy consumed in the acid-containing wastewater concentration and crystallization process. When the consumed fossil energy is coal, the unit is kg; when the consumed fossil energy is natural gas, the unit is Nm 3 ; is the carbon emission factor of the th fossil energy, with the unit of kg CO2 eq / kg or kg CO2 eq / Nm 3 ; The calculation formula for the carbon performance of by-product sulfates in the acid-containing wastewater disposal subsystem is as follows: （5d） Where: is the carbon performance of by - product sulfate in the th acid - containing wastewater treatment subsystem, with the unit of kg CO2 eq; is the mass of by - product sulfate in the th acid - containing wastewater treatment subsystem, in kg; is the cradle-to-gate carbon emission factor of the sulfate, in the unit of kg CO2 eq / kg.

7. The method according to claim 1, characterized in that, The target parameters in the full-life cycle emission reduction target function of the sulfuric acid cycle co-utilization system include: the full-life cycle carbon emissions of the system, the disposal and emissions of acid-containing wastewater, and the full-life cycle operating costs and benefits of the system; The variables when setting different cycle co-utilization scenarios include: the amounts of sulfuric acid with different concentrations respectively subjected to concentration disposal, recycled, co-utilized, and directly disposed of as acid-containing wastewater.

8. An apparatus for quantitatively evaluating the carbon footprint of the entire life cycle of a sulfuric acid recycling symbiotic utilization system, characterized in that, It includes a memory and one or more processors. When the one or more processors execute the executable code stored in the memory, it is used to implement the full-life cycle carbon footprint quantitative evaluation method of the sulfuric acid cycle co-utilization system according to any one of claims 1-7.

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