Method and system for preparing synthesis gas through parallel connection of dry reforming and non-catalytic partial oxidation

Abstract

The invention provides a method and system for preparing synthesis gas through dry reforming parallel non-catalytic partial oxidation, and the method comprises the following steps: carrying out pretreatment operation on raw material gas to obtain pretreated raw material gas, dividing the pretreated raw material gas into two branches, introducing the first branch into a dry reforming self-heating furnace, and introducing the second branch into a dry reforming self-heating furnace; the second branch is mixed with steam and then is introduced into a non-catalytic partial oxidation converter; introducing oxygen and carbon dioxide into a dry reforming reactor, and carrying out a methane dry reforming reaction with the pretreated raw material gas in the presence of a catalyst to obtain first crude synthesis gas; introducing oxygen into the non-catalytic partial oxidation converter, and carrying out methane non-catalytic partial oxidation reaction on the oxygen and the raw material gas to obtain second crude synthesis gas; the first crude synthesis gas and the second crude synthesis gas respectively enter a first waste heat boiler and a second waste heat boiler for heat exchange operation, and after heat recovery, the first crude synthesis gas and the second crude synthesis gas are mixed to obtain mixed crude synthesis gas; and after the mixed crude synthesis gas is subjected to heat exchange operation and refining operation in sequence, the downstream required synthesis gas is finally obtained. The hydrogen-carbon ratio of the synthesis gas can be adjusted in a wide range, the utilization rate of the feed gas is high, and carbon dioxide and heat energy can be fully absorbed.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of syngas preparation, and particularly relates to a method and system for preparing syngas through dry reforming and parallel non-catalytic partial oxidation. BACKGROUND

[0002] Syngas, mainly composed of hydrogen and carbon monoxide, is an important chemical raw material. Syngas is mainly prepared by reforming reaction of methane as raw material. The hydrogen-carbon ratio of syngas varies greatly with the change of raw materials and process. The hydrogen-carbon ratio of syngas produced by different processes ranges from 0.8 to 6.0. The raw materials of syngas are relatively wide, which can be produced from solid fuels such as coal, coke or biomass, and can also be produced from light hydrocarbons such as natural gas, coal bed gas and naphtha. In addition, the fermentation biogas of agricultural and forestry waste, municipal waste and other waste, as well as part of industrial tail gas, can be used to produce syngas. Correspondingly, the downstream products of syngas are various and widely used, and the main chemical products include synthetic ammonia, methanol, acetic acid, dimethyl ether, olefins, gasoline and diesel oil. Therefore, syngas is an important hub connecting upstream resources such as natural gas, oil, coal and biomass with downstream products such as liquid fuel, olefin, acetic acid and aromatic hydrocarbon.

[0003] Different downstream products have different specific requirements for the hydrogen-carbon ratio (H2:CO) of syngas, and the main raw materials and reaction routes determine the hydrogen-carbon ratio of the product syngas. Methane, as one of the main raw materials for syngas, its conversion process covers a variety of reaction routes, including steam reforming, non-catalytic partial oxidation and dry reforming.

[0004] Among them, the steam reforming technology is relatively mature and widely used, and the hydrogen-carbon ratio of the exported syngas is 3-6, which is commonly used in hydrogen production to supply downstream chemical products such as methanol, ammonia, oil refinery, etc. However, due to the need to consume a large amount of steam, there are problems of high energy consumption and carbon deposition. Compared with steam reforming technology, non-catalytic partial oxidation technology does not require catalysts and does not have subsequent complex shift reaction and purification process. When the raw material gas is natural gas, the hydrogen-carbon ratio of the exported syngas is 1.6-2, which can be applied to the production of oil, methanol, ethylene glycol and its derivative products, etc.

[0005] Steam reforming technology and non-catalytic partial oxidation technology are very mature in producing high hydrogen-carbon ratio syngas, which can meet the existing market demand. However, in the downstream application of syngas, such as Fischer-Tropsch synthesis, hydroformylation and DMC production, the demand for low hydrogen-carbon ratio syngas has not been effectively met. The syngas produced by dry reforming technology has a theoretical hydrogen-carbon ratio of 1 and can be adjusted in a wide range, which can fill the market gap of this specific demand. In addition, dry reforming technology has the ability to absorb carbon dioxide. In the Chinese invention patent with the application number CN202321970029.3, a waste heat boiler is used to recover heat in multiple stages to preheat the raw material natural gas at the inlet of the self-heating furnace. Although energy consumption is saved, the raw material gas still needs to be preheated, which increases the equipment cost. In addition, the hydrogen-carbon ratio of the outlet syngas has a small adjustment range, which is difficult to meet the production demand of more products. The Chinese invention patent with the publication number CN106929107A proposes a process of partial oxidation and dry reforming in series to meet the requirement of adjustable hydrogen-carbon ratio. However, due to the large heat exchange demand of the system and the use of a tube reactor for high-temperature and high-pressure reaction in the dry reforming part, it will lead to high investment cost and insufficient operation stability.

[0006] In summary, by adjusting the parameters such as raw material ratio, reaction temperature and pressure, the existing syngas preparation technology can only adjust the hydrogen-carbon ratio of syngas within a certain range, and each process can only meet the demand of part of the products. At the same time, these processes often consume a large amount of energy in the process of preparing syngas. How to expand the adjustment range of the hydrogen-carbon ratio of syngas, effectively reduce the energy consumption, and at the same time improve the preparation efficiency of syngas, is a problem to be solved in the preparation technology of syngas. SUMMARY

[0007] In view of the above-mentioned shortcomings of the prior art, the purpose of the present application is to provide a method and system for preparing syngas by dry reforming and parallel non-catalytic partial oxidation. The method connects the dry reforming part and the non-catalytic partial oxidation part in parallel, fully utilizes the raw material gas, and achieves the purpose of adjusting the hydrogen-carbon ratio of syngas. To achieve the above-mentioned purposes and other related purposes, the present application first provides a method for preparing syngas by dry reforming and parallel non-catalytic partial oxidation, which comprises the following steps:

[0008] S1, obtaining desulfurized raw material gas by pretreating the raw material gas through pressurization, desulfurization and other operations, and dividing the desulfurized raw material gas into two branches, the first branch is introduced into a dry reforming self-heating furnace through a burner, and the second branch is introduced into a non-catalytic partial oxidation converter with steam;

[0009] S2, oxygen and carbon dioxide are introduced into a dry reforming reactor, and methane dry reforming reaction is carried out with the pretreated raw material gas in the presence of a catalyst to obtain a first crude synthesis gas; oxygen is introduced into a non-catalytic partial oxidation converter, and methane non-catalytic partial oxidation reaction is carried out with the raw material gas to obtain a second crude synthesis gas;

[0010] S3, the first crude synthesis gas and the second crude synthesis gas enter a first waste heat boiler and a second waste heat boiler respectively, and after heat recovery, a mixed crude synthesis gas is obtained by mixing;

[0011] S4, the mixed crude synthesis gas is sequentially subjected to heat exchange operation and refining operation, and finally a downstream required synthesis gas is obtained.

[0012] The application also provides a system for preparing synthesis gas by dry reforming and parallel non-catalytic partial oxidation, comprising: a raw material gas pretreatment unit, a dry reforming-non-catalytic partial oxidation combined unit, a heat exchange unit and a refining unit which are sequentially connected; the dry reforming-non-catalytic partial oxidation combined unit comprises a dry reforming unit and a non-catalytic partial oxidation unit which are in parallel distribution, and is used for synthesizing a first crude synthesis gas and a second crude synthesis gas;

[0013] The raw material gas pretreatment unit comprises a pressurizing device, or a desulfurization device, or a pressurizing device and a desulfurization device, and the raw material gas is pretreated and then enters the dry reforming-non-catalytic partial oxidation combined unit;

[0014] The dry reforming unit comprises a dry reforming self-heating furnace and a first waste heat boiler, and a burner which communicates the inside and outside of the reforming self-heating furnace is arranged at the upper part of the dry reforming self-heating furnace, and the first waste heat boiler is arranged in series downstream of the dry reforming self-heating furnace; the non-catalytic partial oxidation unit comprises a non-catalytic partial oxidation converter and a second waste heat boiler which are sequentially connected;

[0015] The discharge end of the dry reforming-non-catalytic partial oxidation combined unit is sequentially connected with the heat exchange unit and the refining unit, which are used for cooling, deaminating, dehydrating and removing carbon dioxide of the crude synthesis gas to obtain a downstream required synthesis gas.

[0016] The application has the following beneficial effects:

[0017] 1) The hydrogen-carbon ratio adjustment range is wide, and the operation flexibility is large. The desulfurized raw material gas is synthesized into a first crude synthesis gas and a second crude synthesis gas by the dry reforming-non-catalytic partial oxidation combined unit, the ratio of the first branch stream and the second branch stream of the raw material gas is adjusted, the hydrogen-carbon ratio of the synthesis gas is adjusted, and the flexible operation mode improves the flexibility of the process, so that the hydrogen-carbon ratio can be finely adjusted according to the actual demand.

[0018] 2) The application has high utilization rate of raw material gas. The raw material gas is directly introduced into the dry reforming-non-catalytic partial oxidation combined unit for dry reforming reaction and non-catalytic partial oxidation reaction in parallel with the dry reforming technology and the non-catalytic partial oxidation technology. According to different downstream syngas requirements, the raw material gas can be fully utilized. Compared with the non-catalytic partial oxidation technology or the dry reforming technology which has a relatively limited hydrogen-carbon ratio adjustment range, the parallel application of the two technologies does not need to separate the syngas, thereby avoiding waste of the raw material gas.

[0019] 3) The process can recycle carbon dioxide and heat energy. According to the requirements, the reaction heat can be recovered and utilized in multiple stages by means of the waste heat boiler, the heat exchanger and the decarburization device, and the carbon dioxide can be recycled and utilized by means of the decarburization device, thereby fully utilizing the carbon dioxide and the heat energy. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 The figure shows a flow system schematic diagram of the dry reforming and parallel non-catalytic partial oxidation for preparing syngas according to the embodiment of the application.

[0021] Figure 2 The figure shows a traditional methane reforming process flow chart.

[0022] Figure 3 The figure shows a traditional non-catalytic partial oxidation process flow chart.

[0023] REFERENCE SIGNS:

[0024] 1 pretreatment unit

[0025] 2 dry reforming autothermal furnace

[0026] 21 burner

[0027] 22 syngas outlet

[0028] 3 first waste heat boiler

[0029] 4 non-catalytic partial oxidation converter

[0030] 5 second waste heat boiler

[0031] 6 fifth heat exchanger

[0032] 7 sixth heat exchanger

[0033] 8 water system device

[0034] 9 decarburization device

[0035] 100 first pipeline

[0036] 200 second pipeline

[0037] 300 first water vapor input pipeline

[0038] 400 carbon dioxide input pipeline

[0039] 500 first oxygen input pipeline

[0040] 501 first heat exchanger

[0041] 600 second oxygen input pipeline

[0042] 601 second heat exchanger

[0043] 700 first boiler feed water pipeline

[0044] 701 third heat exchanger

[0045] 800 second boiler feed water pipeline

[0046] 801 fourth heat exchanger

[0047] 900 second oxygen input pipeline DETAILED DESCRIPTION

[0048] The present application is described herein with reference to specific embodiments thereof which are illustrated in the accompanying drawings. The advantages and features of the present application will become apparent to those skilled in the art upon examination of the following details. Various modifications can be made to the specific embodiments disclosed within the scope and spirit of the present application without departing from the scope of the application. Thus, it should be understood that the following description is not intended to limit the present application to the specific embodiments described.

[0049] The first aspect of the present application provides a method for preparing synthesis gas by dry reforming and parallel non-catalytic partial oxidation, which specifically comprises the following steps:

[0050] S1, obtaining a pretreated feed gas by pretreating a raw material gas, and dividing the pretreated feed gas into two substreams, a first substream being introduced into a dry reforming autothermal furnace, and a second substream being mixed with steam and then introduced into a non-catalytic partial oxidation converter;

[0051] S2, introducing oxygen and carbon dioxide into the dry reforming autothermal furnace to perform a dry reforming reaction with the pretreated feed gas in the presence of a catalyst to obtain a first crude synthesis gas, and introducing oxygen into the non-catalytic partial oxidation converter to perform a non-catalytic partial oxidation reaction with the raw material gas to obtain a second crude synthesis gas;

[0052] S3, introducing the first crude synthesis gas and the second crude synthesis gas into a first waste heat boiler and a second waste heat boiler, respectively, to perform heat exchange operations, and then mixing the two to obtain a mixed crude synthesis gas;

[0053] S4, performing heat exchange operations and refining operations on the mixed crude synthesis gas in sequence to finally obtain a synthesis gas required by a downstream process.

[0054] In step S1, the methane-rich gas can be used as the raw material gas. For example, at least one of natural gas, coal bed gas, coke oven gas, metallurgical waste gas, chemical process purge gas, oil refining process purge gas, hydrogen production tail gas, or two of them can be used simultaneously.

[0055] According to the process or production requirements, the raw material gas can be fed at a rate of 10000-1000000 Nm 3 , for example, 10000-200000 Nm 3 , 200000-400000 Nm 3 , 400000-600000 Nm 3 , 600000-800000 Nm 3 , or 800000-1000000 Nm 3 , which can be 35818 Nm 3 , 36286 Nm 3 , 37886 Nm 3 , 43600 Nm 3 , 53205 Nm 3 , 64378 Nm 3 , or 70045 Nm 3 .

[0056] The pre-treatment operation can be a pressurization operation, or a desulfurization operation, or a pressurization operation and a desulfurization operation. Through the pressurization operation, the conversion rate of the raw material gas is improved; through the desulfurization operation, the damage of sulfides to the catalyst is reduced, and the loss of sulfides to the metal pipeline and equipment is reduced. Specifically, the sulfur content of the raw material gas after the desulfurization operation is less than 0.5 ppm, and preferably less than 0.2 ppm.

[0057] The dry reforming autothermal furnace and the non-catalytic partial oxidation conversion furnace are arranged in parallel. By adjusting the amount of raw material gas distributed to the dry reforming autothermal furnace and the amount of raw material gas distributed to the non-catalytic partial oxidation conversion furnace, the hydrogen-carbon ratio of the synthesis gas is adjusted. More specifically, the pre-treated raw material gas in step S1 is divided into two branches, which are respectively introduced into the dry reforming autothermal furnace and the non-catalytic partial oxidation conversion furnace. The distribution of the raw material gas in the two branches is carried out according to the following scheme, and the distribution ratio of the raw material gas between the dry reforming autothermal furnace and the non-catalytic partial oxidation conversion furnace is:

[0058] 1) when the hydrogen-carbon ratio required by the downstream product is 1.0-1.3, the preferred distribution ratio of the feed gas of the dry reforming autothermal furnace and the non-catalytic partial oxidation converter is (1.4-21):1; 2) when the hydrogen-carbon ratio required by the downstream product is 1.3-1.5, the preferred distribution ratio of the feed gas of the dry reforming autothermal furnace and the non-catalytic partial oxidation converter is (0.6-2.3):1; 3) when the hydrogen-carbon ratio required by the downstream product is 1.5-1.7, the preferred distribution ratio of the feed gas of the dry reforming autothermal furnace and the non-catalytic partial oxidation converter is 1:(0.9-3.8); 4) when the hydrogen-carbon ratio required by the downstream product is 1.7-2.0, the preferred distribution ratio of the feed gas of the dry reforming autothermal furnace and the non-catalytic partial oxidation converter is 1:(1.4-34).

[0059] In a preferred embodiment, the distribution ratio of the feed gas of the aforementioned dry reforming autothermal furnace and the non-catalytic partial oxidation converter is:

[0060] 1) when the hydrogen-carbon ratio required by the downstream product is 1.0-1.3, if coke oven gas is used as the feed gas, the distribution ratio of the feed gas of the dry reforming autothermal furnace and the non-catalytic partial oxidation converter is (2.3-21):1, and if natural gas is used as the feed gas, the distribution ratio of the feed gas of the dry reforming autothermal furnace and the non-catalytic partial oxidation converter is (1.4-5.5):1; 2) when the hydrogen-carbon ratio required by the downstream product is 1.3-1.5, if coke oven gas is used as the feed gas, the distribution ratio of the feed gas of the dry reforming autothermal furnace and the non-catalytic partial oxidation converter is (1.1-2.3):1, and if natural gas is used as the feed gas, the distribution ratio of the feed gas of the dry reforming autothermal furnace and the non-catalytic partial oxidation converter is (0.6-1.4):1; 3) when the hydrogen-carbon ratio required by the downstream product is 1.5-1.7, if coke oven gas is used as the feed gas, the distribution ratio of the feed gas of the dry reforming autothermal furnace and the non-catalytic partial oxidation converter is 1:(0.9-1.4), and if natural gas is used as the feed gas, the distribution ratio of the feed gas of the dry reforming autothermal furnace and the non-catalytic partial oxidation converter is 1:(1.6-3.8); 4) when the hydrogen-carbon ratio required by the downstream product is 1.7-2.0, if coke oven gas is used as the feed gas, the distribution ratio of the feed gas of the dry reforming autothermal furnace and the non-catalytic partial oxidation converter is 1:(1.4-2.3), and if natural gas is used as the feed gas, the distribution ratio of the feed gas of the dry reforming autothermal furnace and the non-catalytic partial oxidation converter is 1:(3.8-34).

[0061] In step S2, the oxygen is preheated to 150-350°C, and then introduced into the dry reforming autothermal furnace and the non-catalytic partial oxidation converter, respectively. Specifically, the oxygen can be preheated to 150-250°C or 250-350°C. The oxygen is introduced into the dry reforming autothermal furnace at an oxygen-carbon ratio (O2 / CH4) of 0.2-1.0, preferably an oxygen-carbon ratio (O2 / CH4) of 0.6-0.8. The amount of oxygen depends on the amount of the specific raw gas and its ratio. Too little oxygen will not reach the reaction temperature, and too much oxygen will result in a too high reaction temperature. The amount of oxygen can be adjusted according to the actual demand, generally within the above range. Specifically, the amount of oxygen introduced into the dry reforming autothermal furnace is 400-250000 Nm 3 , for example, 400-100000 Nm 3 , 100000-200000 Nm 3 , or 200000-250000 Nm 3 . It can be 5308 Nm 3 , 10965 Nm 3 , 13000 Nm 3 , 16366 Nm 3 , 16545 Nm 3 , 19106 Nm 3 . The amount of oxygen introduced into the non-catalytic partial oxidation converter is 500-650000 Nm 3 , for example, 500-150000 Nm 3 , 150000-300000 Nm 3 , 300000-450000 Nm 3 , or 450000-650000 Nm 3 . It can be 1666 Nm 3 , 2574 Nm 3 , 4364 Nm 3 , 5902 Nm 3 , 7151 Nm 3 , 11237 Nm 3 , 20506 Nm 3 .

[0062] Specifically, the dry reforming autothermal furnace comprises a furnace body and a burner communicating the inside and outside of the furnace body, and the burner is used for introducing oxygen and pretreated raw gas. More specifically, the oxygen enters the dry reforming autothermal furnace through an oxygen flow channel. More specifically, the pretreated raw gas enters the dry reforming autothermal furnace through a process gas flow channel. More specifically, the carbon dioxide enters the dry reforming autothermal furnace through a process gas flow channel, or the carbon dioxide and the pretreated raw gas are mixed and then enter the dry reforming autothermal furnace through a process gas flow channel.

[0063] In a preferred embodiment, the pretreated feed gas is preheated before being fed into the dry reforming autothermal reactor. Preferably, the carbon dioxide is preheated to 150-350°C before being fed into the dry reforming autothermal reactor, and more specifically, it can be preheated to 150-250°C or 250-350°C.

[0064] Specifically, the steam is mixed with the pretreated feed gas before being fed into the dry reforming autothermal reactor and the non-catalytic partial oxidation converter, respectively. More specifically, the steam is fed into the dry reforming autothermal reactor through the process gas flow channel, or the steam is mixed with the pretreated feed gas before being fed into the dry reforming autothermal reactor through the process gas flow channel.

[0065] Preferably, the amount of the carbon dioxide fed is 1200-2500000 Nm 3 , which can be 2450, 6000, 7636, 13907, 24123, 36005, 42032 Nm 3 Preferably, the molar ratio of the pretreated feed gas mixed with the carbon dioxide and the steam is H2O:CO2:CH4=1:0.6-3:1, which can prevent the reactor from coking.

[0066] More specifically, the pretreated feed gas is reformed with the carbon dioxide in the presence of a catalyst, which is selected from a carbon-coking-resistant methane-carbon dioxide reforming catalyst, and more specifically, it is selected from a high-dispersion, high-loading and high-activity nickel-based catalyst (NiO / Al). The reaction pressure of the dry reforming autothermal reactor is 0.5-6.0 MPa, for example, 0.5-2.0 MPa, 2.0-3.5 MPa, 3.5-5.0 MPa or 5.0-6.0 MPa, and more specifically, it can be 1 MPa, 2 MPa, 3 MPa, 4 MPa, 5 MPa or 6 MPa. The reaction temperature of the dry reforming autothermal reactor is 600-1200°C, and more specifically, it can be 600-800°C, 800-1000°C or 1000-1200°C, and more specifically, it can be 925°C.

[0067] The reaction pressure of the non-catalytic partial oxidation is 0.5-6.0 MPa, for example, 0.5-6.0 MPa, for example, 0.5-2.0 MPa, 2.0-3.5 MPa, 3.5-5.0 MPa or 5.0-6.0 MPa, and more specifically, it can be 1 MPa, 2 MPa, 3 MPa, 4 MPa, 5 MPa or 6 MPa. The reaction temperature of the non-catalytic partial oxidation converter is 1200-1500°C, and more specifically, it can be 1200-1300°C, 1300-1400°C or 1400-1500°C, and more specifically, it can be 1200°C, 1300°C, 1400°C or 1500°C.

[0068] In step S3, the heat exchange medium of the first waste heat boiler and the second waste heat boiler is boiler feed water, which is preheated and then introduced into the waste heat boiler to produce by-product saturated steam. Specifically, the saturated steam produced by the first waste heat boiler and the second waste heat boiler is divided into two parts, one part is used to supply steam required by the dry reforming autothermal furnace and the non-catalytic partial oxidation reformer, and the other part provides a heat source for oxygen preheating. The energy in the system can be fully utilized, and good economic benefits can be achieved.

[0069] Specifically, the temperature of the first crude synthesis gas and the second crude synthesis gas after passing through the first waste heat boiler and the second waste heat boiler is 200-400℃, which can be 200-300℃ or 300-400℃, and specifically can be 200℃, 250℃, 300℃, 350℃, or 400℃.

[0070] In step S4, after the mixed crude synthesis gas is subjected to heat exchange operation, the temperature is 40-100℃, which can be 40-70℃ or 70-100℃, and specifically can be 40℃, 50℃, 60℃, 70℃, 80℃, 90℃, or 100℃. Specifically, the mixed crude synthesis gas is further subjected to heat recovery after heat exchange, which is used to preheat the boiler feed water of the waste heat boiler.

[0071] The refining operation can be water washing operation, or decarburization operation, or water washing operation and decarburization operation. Specifically, the mixed crude synthesis gas is subjected to water washing operation in the water washing tower to further wash and cool the mixed crude synthesis gas, remove water, remove ammonia and nitrogen, and remove solid carbon. Specifically, the decarburization device is used to perform decarburization operation on the mixed crude synthesis gas to obtain the required synthesis gas downstream. Further, the carbon dioxide removed by the decarburization operation is returned to the upstream and introduced into the integrated burner together with the raw material gas and fresh carbon dioxide to perform dry reforming reaction, thereby realizing recycling and reuse of carbon dioxide.

[0072] The second aspect of the present application provides a system for preparing synthesis gas by dry reforming and parallel non-catalytic partial oxidation, as shown in Figure 1 The embodiment provides a system for preparing synthesis gas by dry reforming and parallel non-catalytic partial oxidation, which comprises, in sequence, a raw material gas pretreatment unit 1, a dry reforming-non-catalytic partial oxidation combined unit, a heat exchange unit, and a refining unit. The dry reforming-non-catalytic partial oxidation combined unit comprises dry reforming units and non-catalytic partial oxidation units distributed in parallel, which are used to synthesize first crude synthesis gas and second crude synthesis gas.

[0073] The above device can be applied to the process for preparing synthesis gas by dry reforming and parallel non-catalytic partial oxidation provided by the first aspect of the present application. After the raw material gas is pretreated by the pretreatment unit, it is divided into two branches. The first branch is subjected to dry reforming reaction by the dry reforming unit to obtain the first crude synthesis gas, and the second branch is subjected to non-catalytic partial oxidation reaction by the non-catalytic partial oxidation unit to obtain the second crude synthesis gas. By adjusting the flow rates of the first branch and the second branch, the hydrogen-carbon ratio of the synthesis gas is adjusted. The first crude synthesis gas and the second crude synthesis gas are combined, cooled by the heat exchange unit, and subjected to deamination and denitrification by the refining unit to obtain the synthesis gas required by the downstream. In summary, the dry reforming reaction unit and the non-catalytic partial oxidation reaction unit are arranged in parallel, which not only can adjust the hydrogen-carbon ratio of the synthesis gas to meet the requirements of various downstream processes, but also can make full use of the raw material gas and improve the atomic utilization rate.

[0074] It is worth noting that in the system for preparing synthesis gas by dry reforming and parallel non-catalytic partial oxidation of the present application, the first branch enters the dry reforming reaction unit, reacts with carbon dioxide to obtain synthesis gas, and recovers carbon dioxide after the refining unit for dry reforming reaction, which fully absorbs carbon dioxide.

[0075] Specifically, the pretreatment unit 1 can be a pressurizing device, or a desulfurization device, or a pressurizing device and a desulfurization device connected in sequence. The raw material gas is pressurized by the pressurizing device to improve the conversion rate of the raw material gas. By desulfurizing the raw material gas, the influence of sulfides on the reaction catalyst is prevented, and the damage to metal pipelines and equipment is reduced.

[0076] In a preferred embodiment, the dry reforming unit comprises a dry reforming autothermal furnace 2 and a first waste heat boiler 3, and the dry reforming autothermal furnace is provided with a burner 21 and a synthesis gas outlet 22 for communicating between the inside and outside of the reforming autothermal furnace, and the first waste heat boiler 3 is arranged downstream of the dry reforming autothermal furnace 2 in series. The non-catalytic partial oxidation unit comprises a non-catalytic partial oxidation converter 4 and a second waste heat boiler 5 connected in sequence.

[0077] In a preferred embodiment, the burner 21 is located at the upper part of the dry reforming autothermal furnace 2 and comprises a process gas flow channel and an oxygen flow channel connected in sequence from outside to inside. Specifically, the process gas flow channel and the oxygen flow channel are annular channels connected in sequence from outside to inside. More specifically, the process gas flow channel is an annular channel or a cylindrical channel.

[0078] In a specific embodiment, a circulating water vapor channel is further arranged between the process gas flow channel and the oxygen flow channel inside the burner. The circulating water vapor channel can be supplied with water vapor as needed. The appropriate amount of water vapor can control the temperature inside the burner, thereby protecting the burner nozzle and prolonging the service life of the burner.

[0079] In a preferred embodiment, the pre-treatment unit 1 is connected to the upper burner 21 of the dry reforming autothermal reactor by a first pipeline 100, and is connected to the non-catalytic partial oxidation converter 4 by a second pipeline 200. Specifically, the first pipeline 100 is connected to a process gas flow channel. The system further comprises a first water vapor input pipeline 300 connected to the process gas flow channel, or a first water vapor input pipeline 300 connected to the first pipeline 100; a second water vapor input pipeline 900 connected to the non-catalytic partial oxidation converter 4, or a second water vapor input pipeline 900 connected to the second pipeline 200. The system further comprises a carbon dioxide input pipeline 400 connected to the process gas flow channel, or a carbon dioxide input pipeline 400 connected to the first pipeline 100. The system further comprises a first oxygen input pipeline 500 connected to an oxygen flow channel, and a second oxygen input pipeline 600 connected to the non-catalytic partial oxidation converter 4, or a second oxygen input pipeline 600 connected to the second pipeline 200. In a specific embodiment, the first oxygen input pipeline 500 and the second oxygen input pipeline 600 are respectively connected to a first heat exchanger 501 and a second heat exchanger 502 for preheating oxygen.

[0080] In a preferred embodiment, the dry reforming unit further comprises a preheating furnace connected between the pre-treatment unit and the dry reforming autothermal reactor 2 for preheating the pre-treated raw gas to provide an initial temperature for the dry reforming reaction of the dry reforming autothermal reactor 2.

[0081] In a preferred embodiment, the heat exchange medium of the first waste heat boiler 3 and the second waste heat boiler 5 is boiler feed water, and the first waste heat boiler 3 and the second waste heat boiler 5 are respectively connected to a first boiler feed water pipeline 700 and a second boiler feed water pipeline 800 for inputting boiler feed water, and the first waste heat boiler 3 and the first boiler feed water pipeline 700 are connected in series through a third heat exchanger 701, and the second waste heat boiler 5 and the second boiler feed water pipeline 800 are connected in series through a fourth heat exchanger 801, so that the water is preheated by the heat exchangers before entering the waste heat boiler, and finally becomes medium-high pressure steam output.

[0082] In order to further utilize the steam heat, the steam generated by the waste heat boiler is divided into at least two branches, a first branch connected to the first water vapor input pipeline 300 and the second water vapor input pipeline 900 for supplying the required protective steam of the dry reforming autothermal reactor 2 and the non-catalytic partial oxidation converter 4, and a second branch connected to the first heat exchanger 501 and the second heat exchanger 502 for providing a heat source for preheating oxygen, fully utilizing the by-product steam and heat energy, and bringing certain economic benefits.

[0083] In a preferred embodiment, the first waste heat boiler 3 and the second waste heat boiler 5 are connected at the outlet end, and the first waste heat boiler 3 and the second waste heat boiler 5 are connected in series with a heat exchange unit, which can be a heat exchanger. Specifically, 1-3 heat exchangers are used in series. In a preferred embodiment, the heat exchange unit includes a fifth heat exchanger 6 and a sixth heat exchanger 7 in series, further recovering low-grade heat to provide heat for the third heat exchanger 701 and the fourth heat exchanger 801.

[0084] In a preferred embodiment, the heat exchange unit is connected in series with a refining unit. Specifically, the refining unit can be a washing device 8, a decarburization device 9, or a washing device 8 and a decarburization device 9 in series. The washing device 8 is used for washing and cooling, removing water and ammonia nitrogen, and removing solid carbon. The decarburization device 9 is selected from one of an MDEA decarburization device, a PSA decarburization device, a gas separation membrane device, or a low-temperature rectification device. Specifically, the decarburization device 9 is provided with a circulating carbon dioxide outlet, which is in communication with the first pipeline 100, or in communication with the process gas flow channel, or in communication with the carbon dioxide input pipeline 400, for recycling and utilizing carbon dioxide.

[0085] In order to better understand the present application, the following refers to specific embodiments, it should be noted that these embodiments are merely descriptive and do not limit the present application in any way.

[0086] Example 1

[0087] 35818Nm 3 The natural gas is sent to a desulfurization device to obtain desulfurized natural gas with a sulfur content of less than 0.2 ppm, and the desulfurized natural gas is divided into two branches with a distribution ratio of 2.46 and sent to the downstream.

[0088] The first branch (25455Nm 3 ) is mixed with 7636Nm 3 carbon dioxide (including fresh carbon dioxide and circulating carbon dioxide) and a small amount of steam, and then sent to a dry reforming self-heating furnace through a burner, while 16545Nm 3 oxygen is introduced to assist combustion and increase the temperature of the reactant, and further dry reforming reaction of methane and carbon dioxide is carried out in the presence of sufficient nickel-based catalyst (NiO / Al catalyst) to obtain synthesis gas. The reaction temperature of the dry reforming reactor is 925℃, and the reaction pressure is 2MPa. The synthesis gas is cooled to 300℃ by a waste heat boiler, and then mixed with another branch of synthesis gas cooled to 300℃.

[0089] The second branch (10364Nm 3 ) is introduced into a non-catalytic partial oxidation conversion furnace, while 7151Nm 3oxygen, and the non-catalytic partial oxidation reaction is carried out in an oxygen-deficient environment to obtain synthesis gas. The reaction temperature of the non-catalytic partial oxidation converter is 1200℃, and the reaction pressure is 4 MPa. The synthesis gas is cooled to 300℃ by a waste heat boiler and mixed with another branch stream of synthesis gas cooled to 300℃.

[0090] After the two branch streams of crude synthesis gas are mixed, they are sequentially introduced into a secondary heat exchanger and a tertiary heat exchanger and cooled to 80℃. After the multi-stage cooled synthesis gas is deaminated and dewatered in a water washing tower, it is introduced into a decarburization device, and after decarburization, synthesis gas with a hydrogen-carbon ratio of 1.2 is obtained. In addition, the waste heat boiler by-product 3 MPa medium-pressure steam is divided into two parts, one part is used to supply steam required by the dry reforming autothermal furnace and the non-catalytic partial oxidation converter, and the other part provides a heat source for the oxygen preheater and the raw material preheater.

[0091] In this embodiment, 35818 Nm 3 Natural gas can produce 100000 Nm 3 Synthesis gas with a hydrogen-carbon ratio of 1.2 meets the synthesis gas demand of the downstream butyl octanol synthesis process by the BASF synthesis method.

[0092] Example 2

[0093] The 36286 Nm 3 Natural gas is sent to a desulfurization device to obtain desulfurized natural gas with a sulfur content of less than 0.2 ppm, and the desulfurized natural gas is divided into two branch streams with a distribution ratio of 1.23 and sent to the downstream.

[0094] The first branch stream (20000 Nm 3 ) is mixed with 6000 Nm 3 Carbon dioxide (including fresh carbon dioxide and recycled carbon dioxide) and a small amount of steam, and then introduced into a dry reforming autothermal furnace through a burner, and 13000 Nm 3 Oxygen is introduced at the same time, which helps to increase the temperature of the reaction material and further promotes the dry reforming reaction of methane and carbon dioxide in the presence of sufficient nickel-based catalyst (NiO / Al catalyst) to obtain synthesis gas. The reaction temperature of the dry reforming reactor is 925℃, and the reaction pressure is 2 MPa. The synthesis gas is cooled to 300℃ by a waste heat boiler and mixed with another branch stream of synthesis gas cooled to 300℃.

[0095] The second branch stream (16286 Nm 3 ) is introduced into a non-catalytic partial oxidation converter, and 11237 Nm 3 Oxygen is introduced at the same time, and the non-catalytic partial oxidation reaction is carried out in an oxygen-deficient environment to obtain synthesis gas. The reaction temperature of the non-catalytic partial oxidation converter is 1200℃, and the reaction pressure is 4 MPa. The synthesis gas is cooled to 300℃ by a waste heat boiler and mixed with another branch stream of synthesis gas cooled to 300℃.

[0096] The two substreams of the crude synthesis gas are mixed, and then sequentially passed into a secondary heat exchanger and a tertiary heat exchanger to be cooled to 80°C. The synthesis gas after multi-stage cooling is passed into a water washing tower to remove ammonia and water, and then into a decarbonization device to obtain synthesis gas with a hydrogen-carbon ratio of 1.33. In addition, the waste heat boiler by-product 3MPa medium-pressure steam is divided into two parts, one part is used to supply steam required by the dry reforming autothermal furnace and the non-catalytic partial oxidation reformer, and the other part provides heat source for the oxygen preheater and the raw material preheater.

[0097] In this embodiment, 36286Nm 3 The natural gas can produce 100000Nm 3 The synthesis gas with a hydrogen-carbon ratio of 1.33 meets the synthesis gas demand of the downstream methanol carbonyl oxidation method for preparing dimethyl carbonate process or synthesis gas for preparing methyl glycolate process.

[0098] Example 3

[0099] The 37886Nm 3 The natural gas is sent into a desulfurization device to obtain desulfurized natural gas with a sulfur content of less than 0.2ppm, and the desulfurized natural gas is divided into two substreams with a distribution ratio of 0.27 and sent to the downstream.

[0100] The first substream (8167Nm 3 ) is mixed with 2450Nm 3 Carbon dioxide (including fresh carbon dioxide and recycled carbon dioxide) and a small amount of steam, and then sent into a dry reforming autothermal furnace through a burner, and 5308Nm 3 Oxygen is also passed in to assist combustion and increase the temperature of the reactant, and further dry reforming reaction of methane and carbon dioxide is carried out in the presence of sufficient nickel-based catalyst (NiO / Al catalyst) to obtain synthesis gas. The reaction temperature of the dry reforming reactor is 925°C, and the reaction pressure is 2MPa. The synthesis gas is cooled to 300°C by a waste heat boiler, and then mixed with the synthesis gas of the other substream cooled to 300°C.

[0101] The second substream (29719Nm 3 ) is passed into a non-catalytic partial oxidation reformer, and 20506Nm3 oxygen is also passed in to carry out non-catalytic partial oxidation reaction to obtain synthesis gas in an oxygen-deficient environment. The reaction temperature of the non-catalytic partial oxidation reformer is 1200°C, and the reaction pressure is 4MPa. The synthesis gas is cooled to 300°C by a waste heat boiler, and then mixed with the synthesis gas of the other substream cooled to 300°C.

[0102] The two substreams of the crude synthesis gas are mixed, and then sequentially passed into a secondary heat exchanger and a tertiary heat exchanger to be cooled to 80°C. The synthesis gas after multi-stage cooling is passed into a water washing tower to remove ammonia and water, and then into a decarbonization device to obtain synthesis gas with a hydrogen-carbon ratio of 1.65. In addition, the waste heat boiler by-product 3MPa medium-pressure steam is divided into two parts, one part is used to supply steam required by the dry reforming autothermal furnace and the non-catalytic partial oxidation reformer, and the other part provides heat source for the oxygen preheater and the raw material preheater.

[0103] In this embodiment, 37886Nm 3 The natural gas can produce 100000Nm 3 The synthesis gas with a hydrogen-carbon ratio of 1.65 meets the synthesis gas demand of the downstream methanol co-production dimethyl carbonate, dimethoxy methane and dimethyl ether process.

[0104] Example 4

[0105] 70045Nm 3 The coke oven gas is sent into a desulfurization device to obtain desulfurized natural gas with a sulfur content of less than 0.2ppm, and the desulfurized natural gas is divided into two substreams with a distribution ratio of 10.01 and sent to the downstream.

[0106] The first substream (63685Nm 3 ) is mixed with 42032Nm 3 Carbon dioxide (including fresh carbon dioxide and recycled carbon dioxide) and a small amount of steam are mixed, and then sent into a dry reforming autothermal furnace through a burner, and 19106Nm 3 Oxygen is also passed in to assist combustion and increase the temperature of the reactant, and further dry reforming reaction of methane and carbon dioxide is carried out in the presence of sufficient nickel-based catalyst (NiO / Al catalyst) to obtain synthesis gas. The reaction temperature of the dry reforming reactor is 925°C, and the reaction pressure is 2MPa. The synthesis gas is cooled to 300°C by a waste heat boiler, and then mixed with the synthesis gas of the other substream cooled to 300°C.

[0107] The second substream (6360Nm 3 ) is passed into a non-catalytic partial oxidation reformer, and 1666Nm 3 Oxygen is also passed in to carry out non-catalytic partial oxidation reaction in an oxygen-deficient environment to obtain synthesis gas. The reaction temperature of the non-catalytic partial oxidation reformer is 1200°C, and the reaction pressure is 4MPa. The synthesis gas is cooled to 300°C by a waste heat boiler, and then mixed with the synthesis gas of the other substream cooled to 300°C.

[0108] The two streams of crude synthesis gas are mixed, and then sequentially passed into a secondary heat exchanger and a tertiary heat exchanger to be cooled to 80°C. The synthesis gas after multi-stage cooling is passed into a water washing tower to remove ammonia and water, and then into a decarbonization device to obtain synthesis gas with a hydrogen-carbon ratio of 1.2. In addition, the waste heat boiler by-product 3MPa medium-pressure steam is divided into two parts, one part is used to supply steam required by the dry reforming autothermal furnace and the non-catalytic partial oxidation reformer, and the other part provides heat source for the oxygen preheater and the raw material preheater.

[0109] In this embodiment, 70045Nm 3 Natural gas can produce 100000Nm 3 Synthesis gas with a hydrogen-carbon ratio of 1.2 meets the synthesis gas requirement of the downstream butyl octanol synthesis process by the BASF synthesis method.

[0110] Example 5

[0111] The 64378Nm 3 Natural gas is sent to a desulfurization device to obtain desulfurized natural gas with a sulfur content of less than 0.2ppm, and the desulfurized natural gas is divided into two streams with a distribution ratio of 5.55 and sent to the downstream.

[0112] The first stream (54554Nm 3 ) is mixed with 36005Nm 3 Carbon dioxide (including fresh carbon dioxide and recycled carbon dioxide) and a small amount of steam, and then sent into a dry reforming autothermal furnace through a burner, while 16366Nm 3 Oxygen is passed in to assist combustion and increase the temperature of the reactant material, and further dry reforming reaction of methane and carbon dioxide is carried out under the action of sufficient nickel-based catalyst (NiO / Al catalyst) to obtain synthesis gas. The reaction temperature of the dry reforming reactor is 925°C, and the reaction pressure is 2MPa. The synthesis gas is cooled to 300°C by a waste heat boiler, and then mixed with the synthesis gas after the other stream is cooled to 300°C.

[0113] The second stream (9824Nm 3 ) is passed into a non-catalytic partial oxidation reformer, while 2574Nm 3 Oxygen is passed in to carry out non-catalytic partial oxidation reaction to obtain synthesis gas. The reaction temperature of the non-catalytic partial oxidation reformer is 1200°C, and the reaction pressure is 4MPa. The synthesis gas is cooled to 300°C by a waste heat boiler, and then mixed with the synthesis gas after the other stream is cooled to 300°C.

[0114] The two substreams of the crude synthesis gas are mixed, and then sequentially passed into a secondary heat exchanger and a tertiary heat exchanger to be cooled to 80℃. After the multi-stage cooling, the synthesis gas is passed into a water washing tower to remove ammonia and water, and then into a decarbonization device to obtain synthesis gas with a hydrogen-carbon ratio of 1.33. In addition, the waste heat boiler produces 3MPa medium-pressure steam, which is divided into two parts, one part is used to supply steam required by the dry reforming autothermal furnace and the non-catalytic partial oxidation reformer, and the other part is used to provide heat source for the oxygen preheater and the raw material preheater.

[0115] In this embodiment, 64378Nm 3 The natural gas can produce 100000Nm 3 The synthesis gas with a hydrogen-carbon ratio of 1.33 meets the synthesis gas demand of the downstream methanol carbonyl oxidation method for preparing dimethyl carbonate process or synthesis gas for preparing methyl glycolate process.

[0116] Example 6

[0117] The 53205Nm 3 The natural gas is sent into a desulfurization device to obtain desulfurized natural gas with a sulfur content of less than 0.2ppm, and the desulfurized natural gas is divided into two substreams with a distribution ratio of 2.19 and sent to the downstream.

[0118] The first substream (36549Nm 3 ) is mixed with 24123Nm 3 Carbon dioxide (including fresh carbon dioxide and recycled carbon dioxide) and a small amount of steam, and then sent into a dry reforming autothermal furnace through a burner, and 10965Nm 3 Oxygen is passed in to assist combustion and increase the temperature of the reactant, and further dry reforming reaction of methane and carbon dioxide is carried out under the action of sufficient nickel-based catalyst (NiO / Al catalyst) to obtain synthesis gas. The reaction temperature of the dry reforming reactor is 925℃, and the reaction pressure is 2MPa. The synthesis gas is cooled to 300℃ by a waste heat boiler, and then mixed with the synthesis gas of the other substream cooled to 300℃.

[0119] The second substream (16656Nm 3 ) is passed into a non-catalytic partial oxidation reformer, and 4364Nm 3 Oxygen is passed in to carry out non-catalytic partial oxidation reaction to obtain synthesis gas. The reaction temperature of the non-catalytic partial oxidation reformer is 1200℃, and the reaction pressure is 4MPa. The synthesis gas is cooled to 300℃ by a waste heat boiler, and then mixed with the synthesis gas of the other substream cooled to 300℃.

[0120] The two substreams of the crude synthesis gas are mixed, and then sequentially passed into a secondary heat exchanger and a tertiary heat exchanger to be cooled to 80°C. The synthesis gas after multi-stage cooling is passed into a water washing tower to remove ammonia and water, and then into a decarbonization device to obtain synthesis gas with a hydrogen-carbon ratio of 1.2. In addition, the waste heat boiler by-product 3MPa medium-pressure steam is divided into two parts, one part is used to supply steam required by the dry reforming autothermal furnace and the non-catalytic partial oxidation reformer, and the other part provides heat source for the oxygen preheater and the raw material preheater.

[0121] In this embodiment, 53205Nm 3 Natural gas can produce 100000Nm 3 Synthesis gas with a hydrogen-carbon ratio of 1.65, which meets the synthesis gas demand of the downstream methanol co-production dimethyl carbonate, dimethoxy methane and dimethyl ether process.

[0122] Example 7

[0123] The 43600Nm 3 Natural gas is sent to a desulfurization device to obtain desulfurized natural gas with a sulfur content of less than 0.2ppm, and the desulfurized natural gas is divided into two substreams with a distribution ratio of 0.94 and sent to the downstream.

[0124] The first substream (21072Nm 3 ) is mixed with 13907Nm 3 Carbon dioxide (including fresh carbon dioxide and recycled carbon dioxide) and a small amount of steam, and then sent into a dry reforming autothermal furnace through a burner, while 10965Nm 3 Oxygen is passed in to assist combustion and increase the temperature of the reactant, and further dry reforming reaction of methane and carbon dioxide is carried out under the action of sufficient nickel-based catalyst (NiO / Al catalyst) to obtain synthesis gas. The reaction temperature of the dry reforming reactor is 925°C, and the reaction pressure is 2MPa. The synthesis gas is cooled to 300°C by a waste heat boiler, and then mixed with the synthesis gas of the other substream cooled to 300°C.

[0125] The second substream (22528Nm 3 ) is passed into a non-catalytic partial oxidation reformer, while 5902Nm 3 Oxygen is passed in to carry out non-catalytic partial oxidation reaction to obtain synthesis gas. The reaction temperature of the non-catalytic partial oxidation reformer is 1200°C, and the reaction pressure is 4MPa. The synthesis gas is cooled to 300°C by a waste heat boiler, and then mixed with the synthesis gas of the other substream cooled to 300°C.

[0126] The two branches of the crude synthesis gas are mixed, and then sequentially passed into a secondary heat exchanger and a tertiary heat exchanger to be cooled to 80°C. The synthesis gas after multi-stage cooling is passed into a water washing tower to remove ammonia and water, and then into a decarbonization device to obtain synthesis gas with a hydrogen-carbon ratio of 2.0. In addition, the waste heat boiler byproduct produces 3 MPa medium-pressure steam, which is divided into two parts, one part is used to supply steam required by the dry reforming autothermal furnace and the non-catalytic partial oxidation reformer, and the other part is used to provide heat source for the oxygen preheater and the raw material preheater.

[0127] In the present embodiment, 43600 Nm 3 The natural gas can produce 100000 Nm 3 The synthesis gas with a hydrogen-carbon ratio of 2.0 meets the synthesis gas requirement of the synthesis gas to methanol process.

[0128] In summary, the system for preparing synthesis gas by dry reforming and parallel non-catalytic partial oxidation of the present application is suitable for the method for preparing synthesis gas by dry reforming and parallel non-catalytic partial oxidation of the present application. By connecting the dry reforming technology and the non-catalytic partial oxidation technology in parallel through the system, the distribution ratio of the pretreated raw material gas passing into the dry reforming autothermal furnace and the non-catalytic partial oxidation reformer is adjusted, the raw material gas is fully utilized, the hydrogen-carbon ratio of the synthesis gas can be adjusted in a wide range, and the downstream process requirements can be met. Moreover, through the waste heat boiler device, the reaction heat energy is recycled and utilized, and through the decarbonization device, the system carbon dioxide is recycled and utilized, which has good economic benefits.

[0129] The above embodiments only exemplarily illustrate the principles and effects of the present application, and are not used to limit the present application. Any person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes completed by those skilled in the art without departing from the spirit and technical thought disclosed by the present application should be covered by the claims of the present application.

Claims

1. A method for preparing synthesis gas by dry reforming and parallel non-catalytic partial oxidation, characterized in that: The method comprises the following steps: S1. Pre-treating the raw gas to obtain pre-treated raw gas, dividing the pre-treated raw gas into two streams, the first stream flowing into a dry reforming autothermal furnace, and the second stream flowing into a non-catalytic partial oxidation reformer after mixing with steam; S2. Passing oxygen and carbon dioxide into a dry reforming autothermal furnace to undergo a methane dry reforming reaction with the pretreated feed gas in the presence of a catalyst to obtain a first crude synthesis gas; passing oxygen into a non-catalytic partial oxidation converter to undergo a methane non-catalytic partial oxidation reaction with the feed gas to obtain a second crude synthesis gas; S3, the first crude synthesis gas and the second crude synthesis gas enter the first waste heat boiler and the second waste heat boiler respectively for heat exchange operation, and after heat recovery, they are mixed to obtain mixed crude synthesis gas; S4. The mixed crude synthesis gas is subjected to heat exchange and refining operations in sequence to finally obtain the synthesis gas required by the downstream.

2. The method for preparing synthesis gas by dry reforming and parallel non-catalytic partial oxidation according to claim 1, characterized in that: In step S1, at least one of the following technical features is included: a1) The raw gas is selected from at least one of natural gas, coalbed methane, coke oven gas, metallurgical waste gas, chemical process purge gas, oil refining process purge gas, and hydrogen production tail gas, or two of these raw gas are used at the same time. The feed rate of the raw gas is 10,000 to 1,000,000 Nm 3 ; a2) the pretreatment operation includes a pressurization operation, or a desulfurization operation, or a pressurization operation and a desulfurization operation. Preferably, the pressure of the raw gas after the pressurization operation is 0.5 to 6.0 MPa; the sulfur content of the raw gas after the desulfurization operation is less than 0.5 ppm; a3) Dry reforming autothermal furnace and non-catalytic partial oxidation reformer arranged in parallel; a4) The distribution ratio of the raw gas between the dry reforming self-heating furnace and the non-catalytic partial oxidation converter is as follows: 1) When the hydrogen-carbon ratio required by the downstream product is 1.0-1.3, the preferred distribution ratio of the raw gas between the dry reforming self-heating furnace and the non-catalytic partial oxidation converter is (1.4-21):1; 2) When the hydrogen-carbon ratio required by the downstream product is 1.3-1.5, the preferred distribution ratio of the raw gas between the dry reforming self-heating furnace and the non-catalytic partial oxidation converter is (0.6-2.3):1; 3) When the hydrogen-carbon ratio required by the downstream product is 1.5-1.7, the preferred distribution ratio of the raw gas between the dry reforming self-heating furnace and the non-catalytic partial oxidation converter is 1:(0.9-3.8); 4) When the hydrogen-carbon ratio required by the downstream product is 1.7-2.0, the preferred distribution ratio of the raw gas between the dry reforming self-heating furnace and the non-catalytic partial oxidation converter is 1:(1.4-34).

3. The method for preparing synthesis gas by dry reforming and parallel non-catalytic partial oxidation according to claim 2, characterized in that: The raw gas distribution ratio of the dry reforming self-heating furnace and the non-catalytic partial oxidation converter is as follows: 1) when the hydrogen-carbon ratio required by the downstream product is 1.0-1.3, if coke oven gas is used as the raw gas, the preferred raw gas distribution ratio of the dry reforming self-heating furnace and the non-catalytic partial oxidation converter is (2.3-21):1; if natural gas is used as the raw gas, the preferred raw gas distribution ratio of the dry reforming self-heating furnace and the non-catalytic partial oxidation converter is (1.4-5.5):1; 2) when the hydrogen-carbon ratio required by the downstream product is 1.3-1.5, if coke oven gas is used as the raw gas, the preferred raw gas distribution ratio of the dry reforming self-heating furnace and the non-catalytic partial oxidation converter is (1.1-2.3):1; if natural gas is used as the raw gas, the preferred raw gas distribution ratio of the dry reforming self-heating furnace and the non-catalytic partial oxidation converter is (1.2-2.3):

1. The ratio is (0.6-1.4):1; 3) when the hydrogen-carbon ratio required by the downstream product is 1.5-1.7, if coke oven gas is used as the raw gas, the preferred distribution ratio of the raw gas for the dry reforming self-heating furnace and the non-catalytic partial oxidation converter is 1:(0.9-1.4); if natural gas is used as the raw gas, the preferred distribution ratio of the raw gas for the dry reforming self-heating furnace and the non-catalytic partial oxidation converter is 1:(1.6-3.8); 4) when the hydrogen-carbon ratio required by the downstream product is 1.7-2.0, if coke oven gas is used as the raw gas, the preferred distribution ratio of the raw gas for the dry reforming self-heating furnace and the non-catalytic partial oxidation converter is 1:(1.4-2.3); if natural gas is used as the raw gas, the preferred distribution ratio of the raw gas for the dry reforming self-heating furnace and the non-catalytic partial oxidation converter is 1:(3.8-34).

4. The method for preparing synthesis gas by dry reforming and parallel non-catalytic partial oxidation according to claim 1, characterized in that: In step S2, at least one of the following technical features is included: b1) mixing the pretreated raw gas with steam and then introducing the mixture into a dry reforming autothermal furnace and a non-catalytic partial oxidation reforming furnace respectively; b2) oxygen is preheated to 150-350°C and then introduced into the dry reforming autothermal furnace and the non-catalytic partial oxidation converter respectively; b3) The oxygen-carbon ratio (O2 / CH4) of the oxygen fed into the dry reforming self-heating furnace is 0.2 to 1.0, and the preferred oxygen feed rate in the dry reforming self-heating furnace is 400 to 250,000 Nm 3 The oxygen feed rate in the non-catalytic partial oxidation converter is 500~650000Nm 3 ; b4) The feed rate of carbon dioxide is 1200~2500000Nm 3 , the molar ratio of the raw gas after mixing with carbon dioxide and water vapor is H2O:CO2:CH4=1:0.6~3:1; b5) The catalyst used is a methane-carbon dioxide reforming catalyst that is resistant to carbon deposition, and a nickel-based catalyst (NiO / Al) is generally used; b6) The reaction pressure of the dry reforming autothermal furnace is 0.5-6.0 MPa, and the reaction temperature is 600-1200°C; the pressure of the non-catalytic partial oxidation reaction is 0.5-6.0 MPa, and the reaction temperature is 1200-1500°C.

5. The method for preparing synthesis gas by dry reforming and parallel non-catalytic partial oxidation according to claim 1, characterized in that: Step S3 includes at least one of the following technical features: c1) The heat exchange medium between the first and second waste heat boilers is boiler feed water. The water is divided into two parts after passing through the first and second waste heat boilers. One part is used to supply steam required by the dry reforming autothermal furnace and the non-catalytic partial oxidation reformer, and the other part provides a heat source for oxygen preheating; c2) The temperature of the first crude synthesis gas and the second crude synthesis gas after passing through the first waste heat boiler and the second waste heat boiler is 200-400°C.

6. The method for preparing synthesis gas by dry reforming and parallel non-catalytic partial oxidation according to claim 1, characterized in that: Step S4 includes at least one of the following technical features: d1) After the mixed crude synthesis gas undergoes heat exchange operation, the temperature thereof is 40-100°C; d2) the refining operation may be a water washing operation, or a decarburization operation, or a water washing operation and a decarburization operation; d3) The mixed crude synthesis gas is subjected to a decarbonization operation to remove carbon dioxide, and the removed carbon dioxide is returned to the upstream to enter the dry reforming autothermal furnace for dry reforming reaction.

7. A system for preparing synthesis gas by dry reforming in parallel with non-catalytic partial oxidation, characterized in that: The invention comprises a raw gas pretreatment unit (1), a dry reforming-non-catalytic partial oxidation combined unit, a heat exchange unit and a refining unit which are connected in sequence. The dry reforming-non-catalytic partial oxidation combined unit comprises a dry reforming unit and a non-catalytic partial oxidation unit which are distributed in parallel.

8. The system for preparing synthesis gas by dry reforming and parallel non-catalytic partial oxidation according to claim 7, characterized in that: Also includes at least one of the following technical features: e1) The pretreatment unit (1) may be a pressurizing device, or a desulfurizing device, or a pressurizing device and a desulfurizing device connected in sequence; e2) The dry reforming unit comprises a dry reforming self-heating furnace (2) and a first waste heat boiler (3), the dry reforming self-heating furnace (2) is provided with a burner (21) and a synthesis gas outlet (22) communicating with the inside and outside of the reforming self-heating furnace, and the first waste heat boiler (3) is arranged in series downstream of the dry reforming self-heating furnace (2); e3) the non-catalytic partial oxidation unit comprises a non-catalytic partial oxidation reformer (4) and a second waste heat boiler (5) which are connected in sequence; e4) The heat exchange unit may be a heat exchanger, preferably 1-3 heat exchangers connected in series; e5) The refining unit may be a washing device (8), or a decarbonization device (9), or a washing device (8) and a decarbonization device (9) arranged in series.

9. The system for preparing synthesis gas by dry reforming and parallel non-catalytic partial oxidation according to claim 8, characterized in that: Also includes at least one of the following technical features: f1) the pretreatment unit (1) is connected to the burner (21) via a first pipe (100), and is connected to the non-catalytic partial oxidation reformer (4) via a second pipe (200). Preferably, the first pipe (100) is connected to the process gas flow channel; f2) The system further comprises a first steam input pipeline (300) and a second steam input pipeline (900), wherein the first steam input pipeline (300) is in communication with the process gas flow channel, or the first steam input pipeline (300) is in communication with the first pipeline (100); the second steam input pipeline (900) is in communication with the non-catalytic partial oxidation reformer (4), or the second steam input pipeline (900) is in communication with the second pipeline (200); f3) the system further comprises a carbon dioxide input pipeline (400), the carbon dioxide input pipeline (400) being connected to the process gas flow channel, or the carbon dioxide input pipeline (400) being connected to the first pipeline (100); f4) The system further comprises a first oxygen input pipeline (500) and a second oxygen input pipeline (600), wherein the first oxygen input pipeline (500) is in communication with the oxygen flow channel, or the first oxygen input pipeline (500) is in communication with the oxygen flow channel; the second oxygen input pipeline (600) is in communication with the non-catalytic partial oxidation converter (4), or the second oxygen input pipeline (600) is in communication with the second pipeline (200), and preferably, the first oxygen input pipeline (500) and the second oxygen input pipeline (600) are respectively connected to a first heat exchanger (501) and a second heat exchanger (502); f5) The first waste heat boiler (3) and the second waste heat boiler (5) are respectively connected to a first boiler feed water pipe (700) and a second boiler feed water pipe (800) for inputting boiler feed water; a third heat exchanger (701) is connected in series between the first waste heat boiler (3) and the first boiler feed water pipe (700); and a fourth heat exchanger (801) is connected in series between the second waste heat boiler (5) and the second boiler feed water pipe (800); f6) The decarbonization device (9) is selected from one of an MDEA decarbonization device, a PSA decarbonization device, a gas separation membrane device or a cryogenic distillation device, and the decarbonization device (9) is provided with a circulating carbon dioxide outlet, and the circulating carbon dioxide outlet is connected to the first pipeline (100), or is connected to the process gas flow channel, or is connected to the carbon dioxide input pipeline (400).

10. Use of the system for preparing synthesis gas by dry reforming and parallel non-catalytic partial oxidation according to any one of claims 7 to 9 in preparing synthesis gas.

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