CN100503790C - Method for producing chemical products in dual-fuel reforming chemical system - Google Patents

Abstract

The method for producing chemical products by the dual-fuel reforming chemical system of the present invention simultaneously comprehensively and efficiently utilizes two fossil fuels, coal and natural gas, to produce chemical products. According to the respective characteristics of coal and natural gas, the high-temperature heat released by coal combustion is supplied to the reforming reaction of natural gas to produce clean syngas, which not only avoids the waste of direct combustion of natural gas in the traditional natural gas to syngas process, but also does not have coal to syngas The complex process and expensive equipment in the process realize the comprehensive utilization of coal and natural gas, which greatly reduces the energy consumption of the product. Compared with the conventional system, the dual-fuel chemical system can reduce the energy consumption by more than 5% for the production of the same product (taking methanol as an example), and replace the high-priced natural gas with cheap coal, which greatly reduces the production cost of chemical products. Under the premise of using expensive coal gasification equipment, the efficient utilization of coal is realized, and it has a good industrialization prospect.

Description

Method for producing chemical products in dual-fuel reforming chemical system

technical field

The invention relates to the technical field of chemical production, and relates to a method for producing chemical products using natural gas and coal as raw materials.

technical background

Methanol is the raw material of many kinds of chemical products, and it has attracted much attention as the main raw material for the production of non-polluting fuel, gasoline modification additive and methyl tert-butyl ether. Along with the shortage of global oil resources, the utilization of natural gas also has a tendency to promote the production of methanol.

Natural gas is a clean, efficient and convenient energy source, and its use plays an important role in the development of the world economy and the improvement of environmental quality. In recent years, my country's natural gas reserves have grown rapidly, and the "West-to-East Gas Pipeline" project will transport natural gas to 9 provinces and cities across the country, creating favorable conditions for the development of my country's natural gas industry. In the 21st century, my country's natural gas production and consumption will increase rapidly, and its proportion in the energy structure will reach 6% to 8%. At present, products using natural gas as raw materials occupy an important position in the chemical industry, such as 84% of ammonia and 90% of methanol in the world are produced with natural gas as raw materials. Natural gas chemical industry has a long history, and a lot of work has been done to reduce production energy consumption. For example, the international advanced level of energy consumption for producing methanol from natural gas has reached less than 30GJ/t. It is very difficult to further reduce production energy consumption on the existing basis.

The industrial production of methanol using coal as raw material has never been interrupted. Since the 1980s, with the increasing scale of production and the industrial application of advanced coal gasification technology, the synthesis of chemical products using coal as raw material has attracted people's attention again due to the reduction in cost. In order to make full use of the abundant coal resources in our country, coal-based chemical products have also been used in industrial applications. Although the coal gasification technology has been greatly developed, the gasification process is still the most energy-intensive process when coal is used as raw material to prepare chemical products. In addition, coal-based syngas contains sulfur and other harmful substances to catalysts, and its carbon-hydrogen ratio does not meet the needs of synthetic chemical products. Subsequent processing of syngas such as desulfurization, conversion, and decarbonization is still required, which also leads to the production of chemical products from coal. High energy consumption. For example, the energy consumption of the more advanced coal-based methanol production is roughly 40-50GJ/t, which is about 30% higher than that of natural gas. In the traditional coal chemical industry, expensive coal gasification equipment is inseparable, and the cost of coal gasification equipment accounts for as high as 40% to 50% of the total equipment cost. As a result, the investment of chemical plants using coal as raw material is much larger than that of natural gas. Chemical plant for raw materials.

Contents of the invention

The object of the present invention is to provide a method for producing chemical products using coal and natural gas as raw materials, aiming at the respective disadvantages of the current chemical production system using coal and natural gas as raw materials and the respective characteristics of the two fossil energy sources of coal and natural gas. The method significantly reduces the raw materials consumed in the preparation of chemical products without increasing the original equipment and investment, and at the same time retains the clean characteristics of the original natural gas chemical industry, thereby achieving the purpose of reducing energy consumption and reducing investment.

Technical scheme of the present invention is as follows:

A method for producing chemical products in a dual-fuel reforming chemical system is provided, which is a method for simultaneously producing chemical products using existing equipment and using natural gas and coal as raw materials. The chemical system used includes a dual-fuel reforming reaction subsystem, Waste heat recovery subsystem, chemical production subsystem; it includes the following processes:

A) Dual-fuel reforming reaction subsystem process: steam from the waste heat recovery subsystem is mixed with natural gas to form feed gas, which enters the preheater and is heated to ≤500°C by flue gas, and then the feed gas enters the reforming reactor for reforming Reaction tube, the catalyst required for the steam reforming reaction of methane is piled up in the reaction tube, the raw material gas undergoes methane/steam reforming reaction in the reaction tube, and at the same time, the reaction heat required for the reforming reaction is composed of coal, purge gas The mixture with air is obtained by combustion in the furnace of the reforming reactor, and the high-temperature flue gas generated by the combustion then enters the preheater to heat the raw material gas, and the generated medium-temperature flue gas enters the waste heat recovery subsystem;

B) Waste heat recovery subsystem process: the high-temperature raw gas and medium-temperature flue gas generated in the reforming process enter the heat exchanger, and exchange heat with water in the heat exchanger to cool down into raw gas and low-temperature flue gas, and the raw gas is supplied to chemical production sub-systems System, to participate in the product production process, the steam generated by the heat exchanger is divided into three streams, one stream is supplied to the reforming reaction subsystem to participate in the reforming process, one stream is used as external steam, and one stream enters the steam turbine to generate power;

C) The process when the chemical production subsystem is a methanol production subsystem: the raw gas from the waste heat recovery subsystem is boosted by the fresh gas compressor and mixed with the recycle gas, and then further compressed by the mixed gas compressor to the methanol synthesis plant Pressure is required to form high-pressure raw material gas; the high-pressure raw material gas is preheated by the regenerator and enters the methanol synthesis tower for methanol synthesis. Methanol product; part of the unreacted gas separated by the separation and refining unit is used as a cycle gas and then enters the mixed gas compressor to continue to participate in the synthesis reaction, and the other part becomes the relaxation gas and is output to the reforming subsystem as fuel.

In the method for producing chemical products in the dual-fuel reforming chemical system, the steam and natural gas in the waste heat recovery subsystem are mixed at a mixing ratio of 1:3 to 1:3.5.

In the method for producing chemical products in the dual-fuel reforming chemical system, when the C) chemical production subsystem is a hydrogen production subsystem: the raw material gas from the waste heat recovery subsystem enters the conversion unit to generate hydrogen, and then enters the hydrogen The separation unit separates the hydrogen.

The method for producing chemical products in the dual-fuel reforming chemical system, the flow of the hydrogen production subsystem: the raw material gas from the waste heat recovery subsystem enters the first-stage shift reactor or the second-stage shift reactor, and the synthesis gas CO is converted into CO ₂ , and part of hydrogen is generated at the same time. The converted gas enters the hydrogen separation unit to separate hydrogen, and the remaining gas is supplied to the reforming subsystem as fuel.

In the method for producing chemical products in the dual-fuel reforming chemical system, the remaining gas, mainly composed of unreacted methane, carbon dioxide, carbon monoxide and a small amount of hydrogen, can be supplied to the reforming subsystem as fuel.

In the method for producing chemical products by the dual-fuel reforming chemical system, the coal is burned in the furnace, using a fixed bed, fluidized bed or spouted bed combustion mode. When a fluidized bed is used, during the combustion process Desulfurization.

In the method for producing chemical products in the dual-fuel reforming chemical system, the B) waste heat recovery subsystem process also includes recovering the condensed water in the syngas after it is cooled.

In the method for producing chemical products by the dual-fuel reforming chemical system, the C) chemical production subsystem is a separate methanol production subsystem and a separate hydrogen production subsystem or a series connection of the two, which is connected in series, that is The methanol production subsystem is the upstream equipment of the hydrogen production subsystem. At this time, the feed gas of the hydrogen production subsystem is changed to the unreacted release gas of the methanol production subsystem, and the unreacted release gas enters the hydrogen separation unit to separate hydrogen; or It enters a first-stage shift reactor or a second-stage shift reactor, and then enters a hydrogen separation unit to separate hydrogen.

The method for producing chemical products by the dual-fuel reforming chemical system, its C) chemical production subsystem, can also be any subsystem using synthesis gas as raw material, such as DME (dimethyl ether), ammonia and gasoline F-T Subsystem for (Fischer-Tropsch) synthesis.

According to the different characteristics of coal and natural gas, the method of the invention makes comprehensive and complementary utilization of coal and natural gas, and rationally utilizes coal while making full use of clean energy (all natural gas is used as chemical raw materials). The dual-fuel chemical system of the present invention is a method for producing chemical products using natural gas and coal as raw materials at the same time. The method combines a low-energy-consumption natural gas chemical product production system with coal, taking into account the cleanness of natural gas and the richness and low price of coal. , avoiding coal gasification and subsequent processing, achieving the goals of clean production and reducing energy consumption, and maintaining low equipment costs (compared with natural gas chemical plants) while achieving high-efficiency coal utilization (compared with coal gasification equipment) flat).

Compared with the conventional system, the dual-fuel system proposed by the invention can save energy by at least 5%. On the premise of not using expensive coal gasification equipment, the efficient utilization of coal is realized, and the purpose of reducing equipment cost is achieved.

The present invention uses natural gas and coal as the method for producing chemical products with dual fuels as raw materials, compared with the existing method for producing chemical products with only one raw material, it has the following characteristics: (1) Utilize cheap coal to replace traditional natural gas In the steam reforming process, natural gas, which accounts for 1/3 of the total consumption of natural gas and has a high price, reduces the production cost of syngas; (2) organically integrates different chemical systems to make up for the syngas utilization that exists when the two systems are produced separately Unreasonable problems improve energy utilization, save energy and reduce production costs.

In summary, in areas rich in coal and natural gas resources, by virtue of the price advantage of raw materials, the method for producing chemical products with dual fuels according to the present invention will greatly reduce the production cost and energy consumption of chemical products, which is very There are practical prospects.

Description of drawings

Fig. 1. is the method schematic flow sheet of the present invention with natural gas and coal as the dual fuel production chemical product of raw material;

Figure 2 is a schematic flow diagram of the dual-fuel reforming subsystem;

Figure 3. Process flow chart of waste heat recovery subsystem

Figure 4. is a schematic flow diagram of the methanol production subsystem;

Figure 5. Schematic flow diagram of the hydrogen production subsystem.

Detailed ways

Please refer to Fig. 1, Fig. 2 and Fig. 3, the method for producing chemical products in the dual-fuel reforming chemical system of the present invention is to utilize existing equipment and use natural gas and coal as raw materials to simultaneously produce chemical products without increasing investment . The chemical system used mainly includes the following three subsystems: dual-fuel reforming reaction subsystem 1, waste heat recovery subsystem 2, and chemical production subsystem 3.

The method provided by the invention is:

Use coal instead of natural gas as the reforming heat source fuel to produce high-quality clean syngas in the dual-fuel reforming subsystem 1, and the high-temperature flue gas and syngas from the dual-fuel reforming subsystem 1 enter the waste heat recovery subsystem 2 to recover heat , to generate high-pressure steam to drive the compressor in the turbine drive system, and the steam extracted from the turbine is supplied to the reforming subsystem 1 as a reactant for the dual-fuel reforming reaction, and the excess steam is exported as a product. The cooled synthesis gas is sent to the chemical production subsystem 3 to produce chemical products, and then the purge gas is sent to the reforming subsystem 1 to be used as fuel for the reforming subsystem 1 together with coal.

The dual fuel reforming subsystem 1 that the present invention uses, its technological process is:

The steam 5 from the waste heat recovery subsystem 2 is mixed with the natural gas 4 to form raw gas, which enters the preheater 16 and is heated to about 500°C by flue gas. Then feed gas enters reforming reactor 17, and reforming reactor 17 is made up of reforming reaction tube 18 and furnace, and the catalyst placed in reaction tube 18 can be any kind of methane steam reforming catalyst, and feed gas is in reaction tube 18 The methane/steam reforming reaction occurs in , and the reaction equation is as follows:

The methane/steam reforming reaction is a strong endothermic reaction, and the reaction heat required for the reforming reaction is obtained by burning the mixture of coal, purge gas and air in the furnace of the reforming reactor 17 . Part of the methane in the feed gas can also be replaced by CO ₂ , and the reaction proceeds to the right at this time. Syngas with high carbon-to-hydrogen ratio can be obtained by replacing part of methane with CO ₂ , and syngas for preparing different chemical products can be obtained by changing the substitution amount. The high-temperature flue gas 10 generated by combustion in the furnace enters the preheater 16 to heat the raw gas, and then enters the waste heat recovery subsystem 2 . Combustion in the furnace can be carried out in various ways, for example, a fluidized bed combustion method can be used to effectively reduce the content of NOx and SOx in the flue gas.

The chemical product production subsystem 3 provided by the present invention can produce various chemical products, and a production system of a certain chemical product can be configured according to requirements to form different chemical product production subsystems. Such as methanol system, dimethyl ether system, hydrogen system and synthetic ammonia system, etc. It is also possible to produce two or more chemical products at the same time, such as methanol/hydrogen system, methanol/synthetic ammonia and dimethyl ether/synthetic ammonia system, etc.

The waste heat recovery subsystem 2 of the present invention includes a steam turbine. The high-pressure superheated steam produced by waste heat recovery subsystem 2 enters the compressor in the steam turbine drive system. At the same time, part of the medium-pressure steam is extracted from the steam turbine to participate in the methane reforming reaction. Excess steam can be provided as a commodity to other users.

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

Please refer to Fig. 1 and Fig. 2 again, the natural gas 4 and the water vapor 5 from the turbine subsystem are mixed in a certain ratio (generally 1:3-1:3.5), and after being preheated by the high-temperature flue gas 10 in the preheater 16 Enter the reaction tube 18 of the dual-fuel reforming reaction subsystem 1, and the reforming reaction occurs on the surface of the catalyst in the reaction tube 18; at the same time, the coal 9 and the purge gas 15 from the chemical production subsystem 3 also enter the reforming reaction The device 17 has a combustion reaction with air in the furnace cavity outside the reaction tube 18, and the high-temperature heat released by the combustion is used for the reforming reaction. The high-temperature raw gas 6 produced by the reforming reaction and the high-temperature flue gas 10 after coal combustion are preheated to natural gas and steam to become medium-temperature flue gas 11, which enters the waste heat recovery subsystem 2, heats high-pressure water 13, and generates high-pressure superheated steam to drive the turbine To drive the process compressor, in addition to driving the compressor, part of the steam 5 is extracted from the steam turbine and sent to the dual-fuel reforming subsystem 1, and the excess steam 14 is exported as a product. The low-temperature flue gas 12 after heat release is directly discharged into the environment, and the raw material gas 7 generated by the waste heat recovery subsystem 2 enters the chemical production subsystem 3 . The chemical production subsystem 3 produces chemical products 8 and discharges the purge gas 15 at the same time. In the dual-fuel reforming reaction subsystem 1, the purge gas 15 can enter the reforming subsystem 1 as fuel for reforming, and can also be used for Other uses, such as hydrogen production. In this example as reforming fuel.

Fig. 2 is a flowchart of the dual-fuel reforming subsystem 1 of the present invention. The steam 5 from the waste heat recovery subsystem 2 is mixed with the natural gas 4 to form raw gas, which enters the preheater 16 and is heated to 500°C by flue gas. Then the raw material gas enters the reforming reactor 17, and the reforming reactor 17 is made up of the reforming reaction tube 18 and the furnace, and the catalyst required for the steam reforming reaction of methane is piled up in the reaction tube 18, and the raw material gas is generated in the reaction tube 18. Methane/steam reforming reaction, methane/steam reforming reaction is a strong endothermic reaction, the reaction heat required for the reforming reaction is generated by the mixture of coal 9, purge gas 15 and air in the furnace of reforming reactor 17 Obtained by burning. The high-temperature flue gas 10 produced by combustion then enters the preheater 16 to heat the raw gas, and then the medium-temperature flue gas 11 enters the waste heat recovery subsystem 2 . The combustion of coal 9 in the furnace can adopt various methods, for example, in order to reduce the pollution of air caused by the combustion of coal 9, the combustion of coal 9 in the furnace can adopt the combustion method of fluidized bed, effectively reduce NOx and SOx in the flue gas content.

FIG. 3 is a process flow diagram of the waste heat recovery subsystem 2 . The high-temperature raw gas 6 and medium-temperature flue gas 11 produced in the reforming process are exchanged with water 13 in the heat exchanger 34 to cool down into raw gas 7 and low-temperature flue gas 12 . The generated steam is divided into three streams, one stream 5 is supplied to the reforming process, one stream 14 is used as external steam, and one stream 32 enters the steam turbine 33 to generate power.

Fig. 4 is a kind of chemical production subsystem 3 of the present invention: the process flow chart of the methanol production subsystem. As shown in Figure 1, the raw gas 7 from the waste heat recovery subsystem 2 is boosted by the fresh gas compressor 19 and mixed with the recycle gas 24, and then further compressed by the mixed gas compressor 20 to the pressure required for methanol synthesis to form a high pressure Raw gas 25. The high-pressure feed gas 25 is preheated by the regenerator 21 and enters the methanol synthesis tower 22 for methanol synthesis. The synthesized product enters the separation and refining unit 23 after releasing heat in the regenerator 21 to separate the methanol and refine it to obtain the methanol product 8 . A part of the unreacted gas continues to participate in the synthesis reaction as the cycle gas 24, and the other part of the unreacted gas 15 is output to the reforming subsystem 1 as fuel.

Fig. 5 is another kind of chemical production subsystem 3 of the present invention: the process flow chart of the hydrogen production subsystem. As shown in Fig. 1 , the raw material gas 7 from the waste heat recovery subsystem 2 enters the first-stage shift reactor 27 and the second-stage shift reactor 28 in order to convert CO in the synthesis gas into CO ₂ and generate part of hydrogen at the same time. In the second-stage shift reactor 28, the shifted gas enters a hydrogen separation unit 29, where hydrogen 30 is separated. The main components of the remaining gas 31 are unreacted methane, carbon dioxide, carbon monoxide and a small amount of hydrogen, which can be supplied to the reforming subsystem 1 as fuel. When the maximum CO conversion rate is not pursued, it can be simplified to a conversion or completely cancel the conversion process. At this time, the amount of hydrogen produced is reduced, but more fuel can be provided to the reforming subsystem 1 .

In the embodiment of the present invention, the methanol production subsystem and the hydrogen production subsystem can be independent subsystems, and these two subsystems can also be connected in series. At this time, the feed gas of the hydrogen production subsystem is changed from the original 7 to the methanol production subsystem. Unreacted blowdown gas 15 of the system. The above subsystems can be selected during design according to different production needs.

Example:

Example 1 is a dual-fuel methanol chemical system. The methanol production subsystem in FIG. 4 is replaced with the chemical production subsystem in FIG. 1 to form a flow chart of the dual-fuel methanol chemical system. The operating conditions of the dual-fuel reforming sub-process are: gasifier outlet flue gas temperature is 920°C; reforming reaction temperature is 850°C, reforming reaction pressure is 2.3 MPa, CH ₄ /H ₂ O is 3:1, a certain The parameters of natural gas and syngas under equilibrium conditions are shown in Table 1. Table 2 shows the composition of the synthesis gas at the outlet of the reforming reactor 17, and Table 3 shows the energy consumption per ton of methanol produced by the dual-fuel chemical system. It can be seen from Table 3 that the dual-fuel methanol system consumes 26.98GJ of natural gas, 5.90GJ of coal, and 1.522t of steam at 0.5Mpa. In order to reveal the advantages of the dual-fuel system, the energy consumption parameters of the separate production system for the production of the same methanol and steam are also listed in the table. For the sake of fairness, the ratio of natural gas and coal consumed in separate production and combined production is taken as 4.572, and the ratio of obtained methanol and steam is taken as 0.657. Production of natural gas-based methanol consumes 29.28GJ The amount of methanol produced by natural gas is 0.91t, and the amount of steam exported at 0.5Mpa is 0.80t; the production of coal-based methanol consumes 4.16GJ; the amount of coal-based methanol produced is 0.09t; the production of coal-based steam consumes 2.24GJ The amount of steam produced by coal is 0.72t. When producing the same methanol and steam as the dual-fuel system, the total energy consumption is 35.68GJ, which is 7.85% lower than that of the dual-fuel system. It can be seen that the dual-fuel system obviously saves fuel consumption when producing methanol, which greatly reduces the energy consumption and production cost of chemical products.

Example 2 is a dual-fuel hydrogen production chemical system. Replacing the hydrogen production subsystem in Figure 5 with the chemical production subsystem in Figure 1 is the flow chart of the dual-fuel hydrogen production system. The separation conditions of the hydrogen production subsystem are pressure 2Mpa, 30-50°C, _H2 molar content 50-90%. The shift gas composition under certain working conditions is shown in Table 4. The shift gas pressure from the shift reactor is sufficient to meet the separation requirements of the shift adsorption (PSA) without additional compression work. More than 80% of hydrogen can be recovered from the shift gas. Table 5 shows the energy consumption of the dual-fuel hydrogen production system to produce 1000Nm ³ hydrogen products. It can be seen from Table 5 that the dual-fuel hydrogen production system consumes 10.87GJ of natural gas, 2.85GJ of coal, and 0.59t of steam at 0.5Mpa. In order to reveal the advantages of the dual-fuel system, the energy consumption parameters of the separate production system for the production of the same hydrogen and steam are also listed in the table. In order to be fair, the ratio of natural gas and coal consumed in separate production and combined production is taken as 3.812, and the ratio of hydrogen and steam obtained is taken as 1707.95. The production of natural gas-based methanol consumes 11.54GJ of natural gas, the amount of hydrogen produced is 888.30Nm ³ , and the amount of steam exported at 0.5Mpa is 0.21t ^; The amount of steam produced by 1.16GJ coal is 0.37t. The total energy consumption of producing the same amount of hydrogen and steam as that of the dual-fuel system is 14.56GJ, and the energy consumption of the dual-fuel system is 5.76% lower than that of the dual-fuel system. It can be seen that the dual-fuel system significantly saves fuel consumption during hydrogen production, greatly reducing energy consumption and production costs of chemical products.

Each logistics parameter in the inventive method, with reference to accompanying drawing, as shown in table 6.

Table 1 State parameters of natural gas and syngas

Table 2 Composition of synthesis gas at reforming reactor outlet

Table 3 Performance comparison of dual-fuel methanol systems

Table 4 Composition of shift gas

Table 5 Performance comparison of dual-fuel hydrogen production system

Table 6 Logistics parameters

Claims (9)

1. A method for producing chemical products in a dual-fuel reforming chemical system is to utilize existing equipment and use natural gas and coal as raw materials to produce chemical products simultaneously. The chemical system used includes a dual-fuel reforming reaction subsystem , the waste heat recovery subsystem, the chemical production subsystem; it is characterized in that it includes the following processes: A) Process flow of dual-fuel reforming reaction subsystem: steam from the waste heat recovery subsystem is mixed with natural gas to form feed gas, which enters the preheater and is heated to about 500°C by flue gas, and then the feed gas enters the reforming reactor for reforming The reaction tube is filled with the catalyst required for the steam reforming reaction of methane. The raw material gas undergoes the methane/steam reforming reaction in the reaction tube. At the same time, the reaction heat required for the reforming reaction is formed by The mixture with air is obtained by combustion in the furnace of the reforming reactor, and the high-temperature flue gas generated by the combustion then enters the preheater to heat the raw material gas, and the generated medium-temperature flue gas enters the waste heat recovery subsystem; B) Waste heat recovery subsystem process: the high-temperature synthesis gas and medium-temperature flue gas generated in the reforming process enter the heat exchanger, and exchange heat with water in the heat exchanger to cool down into synthesis gas and low-temperature flue gas, and the synthesis gas is supplied to chemical production sub-systems System, the steam generated by the heat exchanger is divided into three streams, one stream is supplied to the reforming reaction process, one stream is used as external steam, and the other stream enters the steam turbine for power generation; C) The process when the chemical production subsystem is a methanol production subsystem: the synthesis gas from the waste heat recovery subsystem is boosted by the fresh gas compressor and mixed with the cycle gas, and then further compressed by the mixed gas compressor to the methanol synthesis plant Pressure is required to form high-pressure synthesis gas; the high-pressure synthesis gas is preheated by the regenerator and enters the methanol synthesis tower for methanol synthesis. After the regenerator releases heat, the synthesis product enters the separation and refining unit to separate methanol and refine it to obtain Methanol product; part of the unreacted gas separated by the separation and refining unit is used as a cycle gas and then enters the mixed gas compressor to continue to participate in the synthesis reaction, and the other part becomes the relaxation gas and is output to the reforming subsystem as fuel. 2. The method for producing chemical products in the dual-fuel reforming chemical system according to claim 1, characterized in that: the steam and natural gas in the waste heat recovery subsystem are mixed at a mixing ratio of 1:3 to 1:3.5. 3. according to the method for the dual-fuel reforming chemical industry system production chemical product described in claim 1, it is characterized in that: when described C) chemical industry production subsystem is hydrogen production subsystem: from the synthesis gas that waste heat recovery subsystem comes, Enter the conversion unit to generate hydrogen, and then enter the hydrogen separation unit to separate the hydrogen. 4. According to the method for producing chemical products in the dual-fuel reforming chemical system according to claim 3, it is characterized in that: the flow process of the hydrogen production subsystem: the synthesis gas from the waste heat recovery subsystem enters a first-stage shift reactor or The two-stage shift reactor converts CO in the synthesis gas into CO ₂ and generates part of hydrogen at the same time. The shifted gas enters the hydrogen separation unit to separate the hydrogen, and the remaining gas is supplied to the reforming subsystem as fuel. 5. The method for producing chemical products according to the dual-fuel reforming chemical system of claim 4, characterized in that: the remaining gas, mainly composed of unreacted methane, carbon dioxide, carbon monoxide and a small amount of hydrogen, can be supplied to the reforming subsystem as fuel. 6. according to the method for the production chemical product of dual-fuel reforming chemical industry system claimed in claim 1, it is characterized in that: described coal burns in furnace, adopts the combustion mode of fixed bed, fluidized bed or spouted bed, when adopting In a fluidized bed, desulfurization occurs during combustion. 7. The method for producing chemical products in the dual-fuel reforming chemical system according to claim 1, characterized in that: said B) waste heat recovery subsystem process also includes recovering the condensed water in the syngas after it is cooled. 8. The method for producing chemical products according to the dual-fuel reforming chemical system of claim 1, 3 or 4, is characterized in that: said C) chemical production subsystem is a separate methanol production subsystem and independent hydrogen production The subsystem or the series connection of the two, the series connection means that the methanol production subsystem is the upstream equipment of the hydrogen production subsystem, at this time, the feed gas of the hydrogen production subsystem is changed to the unreacted release gas of the methanol production The release gas enters the hydrogen separation unit to separate the hydrogen; or enters the first-stage shift reactor or the second-stage shift reactor, and then enters the hydrogen separation unit to separate the hydrogen. 9. according to the method for the dual-fuel reforming chemical industry system production chemical product described in claim 1, it is characterized in that: described C) chemical industry production subsystem is also synthesized by DME, ammonia or gasoline F-T taking syngas as raw material subsystem.

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