A method for producing synthesis gas using a COREX melter gasifier dome

Abstract

The application provides a method for preparing synthesis gas by using a COREX smelting gasifier dome, and relates to the technical field of synthesis gas preparation. The method is characterized in that a heat exchanger is installed between a COREX smelting gasifier dome outlet gas pipeline and oxygen and natural gas pipelines, high-temperature sensible heat of dome gas is recovered by using the heat exchanger and is used for preheating of the oxygen and the natural gas; a dome area of the COREX smelting gasifier is used as a reaction zone, preheated oxygen and natural gas are used as raw material gas, the raw material gas is sprayed into the dome area by a burner of the COREX smelting gasifier dome, a non-catalytic partial oxidation reaction of methane is carried out, and synthesis gas mainly composed of hydrogen and carbon monoxide is prepared. The application provides good kinetic conditions for the non-catalytic partial oxidation reaction of the natural gas by the structural setting of an oxygen / natural gas burner and a circulating dust injection burner, the structural setting of the heat exchanger and the control of the composition of the raw material gas, and is beneficial to industrial production practice.

Description

Technical Field

[0001] This invention relates to the technical field of syngas preparation, and more particularly to a method for preparing syngas using the dome of a COREX melt gasifier. Background Technology

[0002] The COREX process is a resource- and environmentally efficient ironmaking method that combines gas reduction and molten gasification processes. It utilizes lump coal instead of expensive metallurgical coke to produce direct reduced iron. Therefore, its product quality is high, and it has broad application prospects.

[0003] The gas temperature generated in the dome area of ​​the COREX molten gasifier can typically reach around 1100°C. Such a high temperature is difficult for the subsequent pre-reduction vertical furnace to accept directly and requires a certain degree of cooling.

[0004] The traditional COREX process involves separating a portion of the top gas, cooling and purifying it, and then re-introducing it into the high-temperature generator gas. This lowers the generator gas temperature to approximately 900°C before it is passed through a cyclone dust collector for dust removal. Clearly, a significant portion of the heat is wasted in this process. Therefore, effectively utilizing the sensible heat of the gasifier's dome gas is a crucial issue that the COREX process needs to address.

[0005] Shell-and-tube heat exchangers are widely used heat exchangers, with permissible operating pressures ranging from high vacuum to 41.5 MPa and operating temperatures from below -100℃ to above 1100℃. They also have advantages such as large capacity, simple structure, high heat exchange efficiency, low cost, and easy cleaning. Shell-and-tube heat exchangers made of ceramic materials further enhance corrosion resistance and high-temperature resistance, achieving a heat exchange efficiency of over 92%, making them the best device for recovering waste heat from high-temperature flue gas.

[0006] Natural gas is a clean energy source with promising applications, boasting the lowest carbon emissions per unit of calorific value among all fossil fuels. China's proven conventional natural gas reserves account for only 1.8% of the world's total, but its consumption is projected to maintain rapid growth for a long time. It is estimated that by 2030, natural gas will account for over 10% of primary energy consumption. Therefore, the efficient and rational utilization of natural gas resources will be a crucial breakthrough for reducing carbon emissions and mitigating the greenhouse effect in the coming decades.

[0007] Natural gas's main component is CH4. Currently, the main reactions for converting CH4 into syngas include steam reforming, carbon dioxide reforming, partial methane oxidation, and combinations thereof, often accompanied by forward / reverse water-gas shift reactions. Steam reforming and carbon dioxide reforming are endothermic reactions, while partial methane oxidation is exothermic. Steam reforming and carbon dioxide reforming commonly use catalysts, which can lead to catalyst deactivation due to carbon buildup, requiring catalyst replacement and causing production interruptions. Non-catalytic partial oxidation, on the other hand, does not require a catalyst. The reaction occurs spontaneously under high temperature, high pressure, and specific feedstock ratios, effectively avoiding catalyst deactivation and reducing production costs. It also features low energy consumption and high tolerance to feedstock impurities.

[0008] The drawback of non-catalytic partial oxidation is that the reaction process is at a high temperature, which places high demands on the high-temperature resistance of the reactor. It requires modification of the reactor structure, selection of reactor materials, and the use of a high-temperature heat recovery device to recover and utilize the sensible heat of the syngas.

[0009] Chinese patent CN113526465A discloses a method for producing syngas from natural gas through non-catalytic partial oxidation combined with carbon dioxide reforming. The method involves introducing a mixture of natural gas, oxygen, and carbon dioxide into a reaction channel via a perforated plate burner, where it is ignited at the burner. The reaction proceeds rapidly, and the product is stably output. The product flows out from the reactor outlet and is cooled and separated using water quenching to obtain syngas. This method clearly combines carbon dioxide reforming and methane partial oxidation. While it can synergistically convert carbon dioxide and methane, it suffers from low carbon dioxide conversion rate and requires structural modifications to the apparatus. The mixed gas has a very short residence time in the reaction zone, the reactor space is limited, and the thermal energy utilization rate is low, making it unsuitable for industrial production.

[0010] Chinese patent CN116621118A discloses a method for producing syngas through the non-catalytic partial oxidation of natural gas coupled with pulverized coal. This method requires an oxygen to methane volume ratio of 0.7-0.9:1, increasing the proportion of oxygen in the feed gas. It also requires adding pulverized coal via high-pressure inert gas and a precision burner designed and installed on the top of the furnace, resulting in high cost and low efficiency. The large amount of pulverized coal added necessitates precise control of the oxygen and carbon dioxide levels in the converter, which can trigger other side reactions, such as the adsorption reaction of methane by pulverized coal, leading to low syngas conversion rate and low thermal energy utilization.

[0011] Chinese patent CN102923659A discloses a method for producing syngas from gaseous or liquid hydrocarbons through quenching non-catalytic partial oxidation. In this method, the syngas produced by non-catalytic partial oxidation is cooled and de-ashed in a washing and cooling chamber through a quenching ring and a downcomer. After being fully wetted with water, the syngas enters a water washing tower for further de-ashing before exiting the boundary area and entering downstream equipment. Obviously, this method does not effectively utilize the thermal energy of the syngas, and the conversion rate of the syngas is low, resulting in high production costs. Summary of the Invention

[0012] The present invention aims to solve two problems: first, the waste of heat caused by the need to add purified cold gas to the top gas generated in the traditional COREX molten gasification furnace for cooling; and second, the problems in current non-catalytic partial oxidation methods for preparing syngas, such as high requirements for reactor heat resistance, low syngas thermal energy utilization rate, low quality, and high impurity content.

[0013] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0014] A method for preparing syngas using the dome of a COREX melt gasifier is disclosed. The method involves installing a heat exchanger between the outlet gas pipeline of the COREX melt gasifier dome and the oxygen and natural gas pipelines. The heat exchanger recovers the high-temperature sensible heat of the dome gas and uses it for preheating the oxygen and natural gas. Using the dome area of ​​the COREX melt gasifier as the reaction zone, and using the preheated oxygen and natural gas as feedstock, the gas is injected into the dome area through burners in the COREX melt gasifier dome to carry out a non-catalytic partial oxidation reaction of methane, thereby producing syngas with hydrogen and carbon monoxide as the main components.

[0015] Preferably, the COREX melting gasifier is a reactor in the COREX system that completes the melting and separation of sponge iron into molten iron and the production of reducing gas required for the reducing shaft furnace, and its dome area is the cavity above the semi-coke fixed bed of the melting gasifier.

[0016] Preferably, the heat exchanger is a ceramic shell-and-tube heat exchanger with a heat exchange efficiency of over 92%.

[0017] Preferably, the burners consist of 6 oxygen burners and 4 circulating dust blowing burners, with 1-6 of the 6 oxygen burners modified into oxygen / natural gas coaxial mixed-injection burners.

[0018] Preferably, the volume ratio of oxygen to natural gas in the raw gas is 0.5-0.7, and it is supplied by pipeline; wherein the methane content of the natural gas reaches more than 90%, and the oxygen is industrial pure oxygen.

[0019] Preferably, the oxygen and natural gas need to be pressurized and preheated by a heat exchanger before being injected into the dome area.

[0020] Preferably, the pressure is increased to 300-450 kPa, and the preheating temperature is 100-450 °C.

[0021] Preferably, the flow rates of oxygen and natural gas, the raw materials, introduced into the dome are 4000-7000 Nm³, respectively. 3 / h and 8000-10000Nm 3 / h.

[0022] Preferably, the reaction time for non-catalytic partial oxidation is 0.004-0.008 s.

[0023] Preferably, the average temperature of the dome area of ​​the molten gasifier is 1050-1150℃, and the temperature of the generated gas is 1100±10℃. The gas passes through a pipeline and enters a heat exchanger for heat exchange and a cyclone dust collector to remove unburned particles and dust. The syngas after dust removal can be fed into the COREX pre-reduction vertical shaft furnace or processed and output as gas.

[0024] Preferably, in the method, the methane conversion rate is 99.6-100%, the carbon monoxide yield is 88.3-90.2%, the hydrogen yield is 65.6-66.2%, and the acetylene yield is 0.04-1.20%. The ratio of carbon monoxide to hydrogen in the syngas will reach 95-98%, with carbon monoxide accounting for approximately 45% and hydrogen accounting for approximately 55%.

[0025] Preferably, by recovering and utilizing the waste heat from the high-temperature generated coal gas, the heat exchange efficiency of the existing shell-and-tube heat exchanger can be achieved per 10,000 m³. 3 It is estimated that the generation of coal gas can save 8.3346 × 10⁻⁶ thermal energy. 9 J, approximately 284 kg of standard coal.

[0026] The principle of this invention:

[0027] The COREX molten gasifier is one of the main reactors in the COREX molten reduction ironmaking process. Based on the different chemical reactions and functions, the molten gasifier can be divided into four zones from top to bottom: (i) the dome free space; (ii) the coal-filled bed; (iii) the tuyeres swirl zone; and (iv) the hearth zone. The dome zone of the COREX molten gasifier is a free space with high temperature, high pressure, and relatively intense turbulent kinetic energy.

[0028] This invention fully utilizes the dome area of ​​the COREX molten gasifier and couples it with non-catalytic partial oxidation technology to produce syngas. On the one hand, it can provide high-quality reducing gas to meet the needs of iron-containing raw material reduction in the COREX pre-reduction shaft furnace, further improving the metallization rate of ore in the shaft furnace. On the other hand, it produces a large amount of low-cost, high-quality syngas for the production of coal chemical products such as methanol and ethylene glycol, promoting the formation of a low-carbon and green "steel-chemical" production model and reducing CO2 emissions from the process.

[0029] To meet the reaction requirements of non-catalytic partial oxidation and leverage its advantages, this invention introduces non-catalytic partial oxidation into the COREX melt reduction process, using the dome region of the COREX melt gasifier as the reaction zone. There are two reasons for this: First, the flame temperature of non-catalytic partial oxidation can reach 1800℃, while the tuyeres and dome of the melt gasifier can withstand temperatures exceeding 2000℃, thus the high-temperature resistance of the melt gasifier dome meets the requirements of non-catalytic partial oxidation. Second, the high-pressure environment and high-speed gas flow at the dome of the COREX melt gasifier provide favorable kinetic conditions for the non-catalytic partial oxidation of natural gas. Specifically, the non-catalytic partial oxidation of natural gas is a gas-phase reaction (1-1). The higher pressure within the reactor favors the forward reaction, and the high-speed gas flow allows for rapid mixing and complete reaction of natural gas and oxygen.

[0030]

[0031] The heat required for the non-catalytic partial oxidation reaction is partly provided by the heat carried by the rising coal gas in the lower semi-coke fixed bed of the COREX molten gasifier. The rising furnace gas carries the heat generated by the combustion of coal in the lower semi-coke fixed bed into the dome zone. Another part is provided by a small portion of the natural gas undergoing complete combustion reaction (1-2) near the oxygen / natural gas coaxial mixed-injection burner area. The local ignition temperature of complete combustion can reach 1800-2300℃. Under the combined effect of the two, a high temperature of 1050-1150℃ will be generated in the dome zone. The natural gas consumed by complete combustion accounts for about 1 / 3 of the total natural gas.

[0032]

[0033] While the non-catalytic partial oxidation of natural gas occurs in the dome region, reforming reactions of natural gas, water vapor, and carbon dioxide also occur (1-3)(1-4), producing hydrogen and carbon monoxide, which will further increase the content of effective components in the syngas.

[0034]

[0035]

[0036] The above technical solution has at least the following advantages compared with the existing technology:

[0037] The present invention proposes a method for preparing syngas using the dome of a COREX molten gasifier, which can solve the technical problems in the prior art that are not conducive to the non-catalytic partial oxidation of natural gas, such as reactor material and space, catalyst addition, and coal or pulverized coal addition. At the same time, it solves the technical problem of obviously recovering and reusing the syngas produced in this process, and improves the conversion rate and thermal energy utilization rate of syngas.

[0038] This invention utilizes the dome region of a COREX molten gasifier to perform a non-catalytic partial oxidation reaction, which not only meets the high requirements of the reactor for heat resistance, but also allows for effective control of the reaction environment in the dome region. The control method is convenient and has the advantages of low cost and low pollution.

[0039] The dome area of ​​the COREX melting gasifier of this invention has a high-pressure environment and high-speed airflow. The reaction of the raw material gas is controlled by the oxygen / natural gas burners and the circulating dust injection burners to produce high-quality syngas and significantly improve the quality of the reducing gas produced by the COREX melting gasifier. This is beneficial to improving the reduction effect of the COREX pre-reduction vertical furnace and enhancing the quality of the pre-reduction product.

[0040] This invention achieves heat exchange between the gas pipeline at the arch outlet and the oxygen and natural gas pipelines by installing a heat exchanger, which uses an external heat transfer medium to achieve heat transfer between the pipelines and thus achieves heat exchange of the flowing gas. At the same time, the COREX process does not require the separation of some gas for cooling and purification before adding it to the hot gas at the arch outlet, thus improving the thermal energy utilization rate.

[0041] The syngas prepared by the non-catalytic partial oxidation in the COREX melt gasification furnace of this invention has high industrial value, a wide range of applications, high yields of hydrogen and carbon monoxide in the syngas, low heat energy consumption, and high heat energy utilization rate, making it suitable for industrial production practice.

[0042] In summary, compared with other traditional methods, the method of this invention adopts a reforming reaction technology solution of non-catalytic partial oxidation of natural gas with natural gas, water vapor, and carbon dioxide, which is not found in the prior art. Through the structural design of oxygen / natural gas burners and circulating dust injection burners, the structural design of heat exchangers, and the control of the composition of raw gas, combined with the high-pressure environment and high-speed gas flow in the dome area of ​​the COREX molten gasifier, good kinetic conditions are provided for the non-catalytic partial oxidation reaction of natural gas. The method is simple to operate, has low production cost, high efficiency, and is conducive to large-scale industrial production and promotion. Attached Figure Description

[0043] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0044] Figure 1This is a schematic diagram of the apparatus for a method of preparing syngas using the dome of a COREX melt gasifier according to the present invention, wherein: 1 is a COREX melt gasifier, 2 is a tubular gas heat exchanger, 3 is a natural gas pressure regulating valve, 4 is an oxygen pressure regulating valve, 5 is an oxygen / natural gas coaxial mixed-injection burner, 6 is a hot coal gas cyclone dust collector, 7 is a first scrubbing tower, 8 is a second scrubbing tower, 9 is a COREX pre-reduction vertical furnace, and 10 is a coal bunker;

[0045] Figure 2 This is a schematic diagram of the burner distribution along the axial cross section of the furnace body in the apparatus structure of a method for preparing syngas using the dome of a COREX melting gasifier according to the present invention, after 1-6 of the 6 oxygen burners have been modified into oxygen / natural gas coaxial mixed injection burners. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0047] A method for preparing syngas using the dome of a COREX melt gasifier is disclosed. The method involves installing a heat exchanger between the outlet gas pipeline of the COREX melt gasifier dome and the oxygen and natural gas pipelines. The heat exchanger recovers the high-temperature sensible heat of the dome gas and uses it for preheating the oxygen and natural gas. Using the dome area of ​​the COREX melt gasifier as the reaction zone, and using the preheated oxygen and natural gas as feedstock, the gas is injected into the dome area through burners in the COREX melt gasifier dome to carry out a non-catalytic partial oxidation reaction of methane, thereby producing syngas with hydrogen and carbon monoxide as the main components.

[0048] Specifically, the COREX melting gasifier is a reactor in the COREX system that completes the melting and separation of sponge iron into molten iron and the production of reducing gas required for the reducing shaft furnace. Its dome area is the cavity above the semi-coke fixed bed of the melting gasifier.

[0049] Specifically, the heat exchanger is a ceramic shell-and-tube heat exchanger with a heat exchange efficiency of over 92%.

[0050] Specifically, the burners consist of 6 oxygen burners and 4 circulating dust-blowing burners, with 1-6 of the 6 oxygen burners modified into oxygen / natural gas coaxial mixed-injection burners.

[0051] Specifically, the volume ratio of oxygen to natural gas in the raw gas is 0.5-0.7, and it is supplied via pipeline; wherein the methane content of the natural gas reaches more than 90%, and the oxygen is industrial pure oxygen.

[0052] In particular, oxygen and natural gas need to be pressurized and preheated by heat exchangers before being injected into the vault area.

[0053] Specifically, pressurize until the pressure reaches 300-450 kPa, and preheat the temperature to 100-450 °C.

[0054] Specifically, the flow rates of oxygen and natural gas, the raw materials, introduced into the dome are 4000-7000 Nm³, respectively. 3 / h and 8000-10000Nm 3 / h.

[0055] Specifically, the reaction time for non-catalytic partial oxidation is 0.004-0.008 s.

[0056] Specifically, the average temperature of the dome area of ​​the molten gasifier is 1050-1150℃, and the temperature of the generated gas is 1100±10℃. The gas passes through a pipeline to a heat exchanger for heat exchange and a cyclone dust collector to remove unburned particles and dust. The syngas after dust removal can be fed into the COREX pre-reduction vertical shaft furnace or processed and output as gas.

[0057] Specifically, in the method, the methane conversion rate is 99.6-100%, the carbon monoxide yield is 88.3-90.2%, the hydrogen yield is 65.6-66.2%, and the acetylene yield is 0.04-1.20%. The ratio of carbon monoxide to hydrogen in the syngas will reach 95-98%, with carbon monoxide accounting for approximately 45% and hydrogen accounting for approximately 55%.

[0058] In particular, by recovering and utilizing the waste heat from the high-temperature generated coal gas, the heat exchange efficiency of existing shell-and-tube heat exchangers can be improved per 10,000 m³. 3 It is estimated that the generation of coal gas can save 8.3346 × 10⁻⁶ thermal energy. 9 J, approximately 284 kg of standard coal.

[0059] Example 1

[0060] A method for preparing syngas using the dome of a COREX melt gasification furnace, the main equipment and components involved are as follows: Figure 1 As shown, it includes a COREX melting gasifier 1, a tubular gas heat exchanger 2, a natural gas pressure regulating valve 3, an oxygen pressure regulating valve 4, an oxygen / natural gas coaxial mixed-injection burner 5, a hot coal gas cyclone dust collector 6, a scrubbing tower 7, a scrubbing tower 8, a COREX pre-reduction vertical shaft furnace 9, and a coal bunker 10. Figure 2As shown, the dome area of ​​the COREX molten gasifier is the cavity above the semi-coke fixed bed in the molten gasifier. The burners are 6 oxygen burners and 4 circulating dust injection burners. 6 of the 6 oxygen burners are modified into oxygen / natural gas coaxial mixed injection burners 5.

[0061] A method for preparing syngas using the dome of a COREX melt gasifier, the specific steps of which are as follows:

[0062] Step 1: Select natural gas and oxygen as raw materials, and introduce them into the natural gas pressure regulating valve 3 and oxygen pressure regulating valve 4 through the corresponding gas supply pipelines to increase the pressure to 330 kPa;

[0063] Step 2: The natural gas and oxygen after the pressure was increased in Step 1 are respectively introduced into the tubular gas heat exchanger 2 connected to the natural gas pressure regulating valve 3 and the oxygen pressure regulating valve 4 and preheated to a temperature of 300℃.

[0064] Step 3: The preheated natural gas and oxygen from Step 2 are transported to the COREX melting gasification furnace (part of the oxygen is used for injection into the lower part of the furnace, such as...). Figure 1 (Illustrated), the oxygen / natural gas is mixed and injected into the dome area through the oxygen / natural gas coaxial mixing burner 5, wherein the volume ratio of oxygen to natural gas is 0.55, and the injection ratio of natural gas and oxygen can be effectively adjusted through the natural gas pressure regulating valve 3 and the oxygen pressure regulating valve 4;

[0065] Step 4: In the dome area, oxygen and natural gas mix rapidly under the action of high-speed airflow. A small portion of the natural gas will undergo a complete combustion reaction with the oxygen, releasing a large amount of heat. The local ignition temperature can reach 1800-2300℃. At the same time, the rising furnace gas carries the heat generated by the combustion of coal in the lower semi-coke fixed bed into the dome area. Under the combined effect of the two, a high temperature of about 1050℃ will be generated in the dome area.

[0066] Step 5: The unreacted natural gas from Step 4 will continue to undergo a non-catalytic partial oxidation reaction with oxygen under high temperature and pressure to produce carbon monoxide and hydrogen syngas. After a period of reaction, carbon dioxide and water vapor in the gas phase will also undergo a reforming reaction with the natural gas in the dome, producing carbon monoxide and hydrogen. This will further increase the effective component ratio of the syngas.

[0067] Step Six: After the gas phase in Step Five has fully reacted, and the sensible heat has been recovered through the tubular gas heat exchanger, its temperature is acceptable to the hot coal gas cyclone dust collector 6. After treatment by the hot coal gas cyclone dust collector 6, the dust content will be reduced to 20g / m³. 3 about;

[0068] Step 7: The gas after dust removal can be used as the reducing gas of COREX pre-reduction shaft furnace 9 or, together with the top gas of COREX pre-reduction shaft furnace 9, can be washed and purified by the first scrubbing tower 7 and the first scrubbing tower 8 before being used as output gas. The dust is then blown back into the COREX melting gasifier 1.

[0069] In the method described in this embodiment, the methane conversion rate is 99.6-100%, the carbon monoxide yield is 88.3-90.2%, the hydrogen yield is 65.6-66.2%, the acetylene yield is 0.04-1.20%, and the syngas contains approximately 45% carbon monoxide and approximately 55% hydrogen.

[0070] Example 2

[0071] A method for preparing syngas using the dome of a COREX melt gasification furnace, the main equipment and components involved are as follows: Figure 1 As shown, the system includes a COREX molten gasifier 1, a tubular gas heat exchanger 2, a natural gas pressure regulating valve 3, an oxygen pressure regulating valve 4, an oxygen / natural gas coaxial mixed-injection burner 5, a hot coal gas cyclone dust collector 6, a scrubbing tower 7, a scrubbing tower 8, a COREX pre-reduction vertical shaft furnace 9, and a coal bunker 10. The dome area of ​​the COREX molten gasifier is the cavity above the semi-coke fixed bed in the molten gasifier. The burners consist of 6 oxygen burners and 4 circulating dust injection burners, with 6 of the 6 oxygen burners modified into oxygen / natural gas coaxial mixed-injection burners 5.

[0072] A method for preparing syngas using the dome of a COREX melt gasifier, the specific steps of which are as follows:

[0073] Step 1: Select natural gas and oxygen as raw materials, and introduce them into the natural gas pressure regulating valve 3 and oxygen pressure regulating valve 4 through the corresponding gas supply pipelines to increase the pressure to 350 kPa;

[0074] Step 2: The natural gas and oxygen after the pressure was increased in Step 1 are respectively introduced into the tubular gas heat exchanger 2 connected to the natural gas pressure regulating valve 3 and the oxygen pressure regulating valve 4 and preheated to a temperature of 350℃.

[0075] Step 3: The preheated natural gas and oxygen from Step 2 are transported to the COREX melting gasification furnace (part of the oxygen is used for injection into the lower part of the furnace, such as...). Figure 1 (Illustrated), the oxygen / natural gas is mixed and injected into the dome area through the oxygen / natural gas coaxial mixing burner 5, wherein the volume ratio of oxygen to natural gas is 0.60, and the injection ratio of natural gas and oxygen can be effectively adjusted through the natural gas pressure regulating valve 3 and the oxygen pressure regulating valve 4;

[0076] Step 4: In the dome area, oxygen and natural gas mix rapidly under the action of high-speed airflow. A small portion of the natural gas will undergo a complete combustion reaction with the oxygen, releasing a large amount of heat. The local ignition temperature can reach 1800-2300℃. At the same time, the rising furnace gas carries the heat generated by the combustion of coal in the lower semi-coke fixed bed into the dome area. Under the combined effect of the two, a high temperature of about 1070℃ will be generated in the dome area.

[0077] Step 5: The unreacted natural gas from Step 4 will continue to undergo a non-catalytic partial oxidation reaction with oxygen under high temperature and pressure to produce carbon monoxide and hydrogen syngas. After a period of reaction, carbon dioxide and water vapor in the gas phase will also undergo a reforming reaction with the natural gas in the dome, producing carbon monoxide and hydrogen. This will further increase the effective component ratio of the syngas.

[0078] Step Six: After the gas phase in Step Five has fully reacted, and the sensible heat has been recovered through the tubular gas heat exchanger, its temperature is acceptable to the hot coal gas cyclone dust collector 6. After treatment by the hot coal gas cyclone dust collector 6, the dust content will be reduced to 20g / m³. 3 about;

[0079] Step 7: The gas after dust removal can be used as the reducing gas of COREX pre-reduction shaft furnace 9 or, together with the top gas of COREX pre-reduction shaft furnace 9, can be washed and purified by the first scrubbing tower 7 and the first scrubbing tower 8 before being used as output gas. The dust is then blown back into the COREX melting gasifier 1.

[0080] In the method described in this embodiment, the methane conversion rate is 99.6-100%, the carbon monoxide yield is 88.6-90.2%, the hydrogen yield is 65.7-66.2%, the acetylene yield is 0.04-1.20%, and the syngas contains approximately 45% carbon monoxide and approximately 55% hydrogen.

[0081] Example 3

[0082] A method for preparing syngas using the dome of a COREX melt gasification furnace, the main equipment and components involved are as follows: Figure 1 As shown, the system includes a COREX molten gasifier 1, a tubular gas heat exchanger 2, a natural gas pressure regulating valve 3, an oxygen pressure regulating valve 4, an oxygen / natural gas coaxial mixed-injection burner 5, a hot coal gas cyclone dust collector 6, a scrubbing tower 7, a scrubbing tower 8, a COREX pre-reduction vertical shaft furnace 9, and a coal bunker 10. The dome area of ​​the COREX molten gasifier is the cavity above the semi-coke fixed bed in the molten gasifier. The burners consist of 6 oxygen burners and 4 circulating dust injection burners, with 6 of the 6 oxygen burners modified into oxygen / natural gas coaxial mixed-injection burners 5.

[0083] A method for preparing syngas using the dome of a COREX melt gasifier, the specific steps of which are as follows:

[0084] Step 1: Select natural gas and oxygen as raw materials, and introduce them into the natural gas pressure regulating valve 3 and oxygen pressure regulating valve 4 through the corresponding gas supply pipelines to increase the pressure to 370 kPa;

[0085] Step 2: The natural gas and oxygen after the pressure was increased in Step 1 are respectively introduced into the tubular gas heat exchanger 2 connected to the natural gas pressure regulating valve 3 and the oxygen pressure regulating valve 4 and preheated to a temperature of 380℃.

[0086] Step 3: The preheated natural gas and oxygen from Step 2 are transported to the COREX melting gasification furnace (part of the oxygen is used for injection into the lower part of the furnace, such as...). Figure 1 (Illustrated), the oxygen / natural gas is mixed and injected into the dome area through the oxygen / natural gas coaxial mixing burner 5, wherein the volume ratio of oxygen to natural gas is 0.60, and the injection ratio of natural gas and oxygen can be effectively adjusted through the natural gas pressure regulating valve 3 and the oxygen pressure regulating valve 4;

[0087] Step 4: In the dome area, oxygen and natural gas mix rapidly under the action of high-speed airflow. A small portion of the natural gas will undergo a complete combustion reaction with the oxygen, releasing a large amount of heat. The local ignition temperature can reach 1800-2300℃. At the same time, the rising furnace gas carries the heat generated by the combustion of coal in the lower semi-coke fixed bed into the dome area. Under the combined effect of the two, a high temperature of about 1090℃ will be generated in the dome area.

[0088] Step 5: The unreacted natural gas from Step 4 will continue to undergo a non-catalytic partial oxidation reaction with oxygen under high temperature and pressure to produce carbon monoxide and hydrogen syngas. After a period of reaction, carbon dioxide and water vapor in the gas phase will also undergo a reforming reaction with the natural gas in the dome, producing carbon monoxide and hydrogen. This will further increase the effective component ratio of the syngas.

[0089] Step Six: After the gas phase in Step Five has fully reacted, and the sensible heat has been recovered through the tubular gas heat exchanger, its temperature is acceptable to the hot coal gas cyclone dust collector 6. After treatment by the hot coal gas cyclone dust collector 6, the dust content will be reduced to 20g / m³. 3 about;

[0090] Step 7: The gas after dust removal can be used as the reducing gas of COREX pre-reduction shaft furnace 9 or, together with the top gas of COREX pre-reduction shaft furnace 9, can be washed and purified by the first scrubbing tower 7 and the first scrubbing tower 8 before being used as output gas. The dust is then blown back into the COREX melting gasifier 1.

[0091] In the method described in this embodiment, the methane conversion rate is 99.6-100%, the carbon monoxide yield is 88.9-90.2%, the hydrogen yield is 65.7-66.2%, the acetylene yield is 0.04-1.20%, and the syngas contains approximately 45% carbon monoxide and approximately 55% hydrogen.

[0092] Example 4

[0093] A method for preparing syngas using the dome of a COREX melt gasification furnace, the main equipment and components involved are as follows: Figure 1 As shown, the system includes a COREX molten gasifier 1, a tubular gas heat exchanger 2, a natural gas pressure regulating valve 3, an oxygen pressure regulating valve 4, an oxygen / natural gas coaxial mixed-injection burner 5, a hot coal gas cyclone dust collector 6, a scrubbing tower 7, a scrubbing tower 8, a COREX pre-reduction vertical shaft furnace 9, and a coal bunker 10. The dome area of ​​the COREX molten gasifier is the cavity above the semi-coke fixed bed in the molten gasifier. The burners consist of 6 oxygen burners and 4 circulating dust injection burners, with 6 of the 6 oxygen burners modified into oxygen / natural gas coaxial mixed-injection burners 5.

[0094] A method for preparing syngas using the dome of a COREX melt gasifier, the specific steps of which are as follows:

[0095] Step 1: Select natural gas and oxygen as raw materials, and introduce them into the natural gas pressure regulating valve 3 and oxygen pressure regulating valve 4 through the corresponding gas supply pipelines to increase the pressure to 380 kPa;

[0096] Step 2: The natural gas and oxygen after the pressure was increased in Step 1 are respectively introduced into the tubular gas heat exchanger 2 connected to the natural gas pressure regulating valve 3 and the oxygen pressure regulating valve 4 and preheated to a temperature of 400℃.

[0097] Step 3: The preheated natural gas and oxygen from Step 2 are transported to the COREX melting gasification furnace (part of the oxygen is used for injection into the lower part of the furnace, such as...). Figure 1 (Illustrated), the oxygen / natural gas is mixed and injected into the dome area through the oxygen / natural gas coaxial mixing burner 5, wherein the volume ratio of oxygen to natural gas is 0.65, and the injection ratio of natural gas and oxygen can be effectively adjusted through the natural gas pressure regulating valve 3 and the oxygen pressure regulating valve 4;

[0098] Step 4: In the dome area, oxygen and natural gas mix rapidly under the action of high-speed airflow. A small portion of the natural gas will undergo a complete combustion reaction with the oxygen, releasing a large amount of heat. The local ignition temperature can reach 1800-2300℃. At the same time, the rising furnace gas carries the heat generated by the combustion of coal in the lower semi-coke fixed bed into the dome area. Under the combined effect of the two, a high temperature of about 1110℃ will be generated in the dome area.

[0099] Step 5: The unreacted natural gas from Step 4 will continue to undergo a non-catalytic partial oxidation reaction with oxygen under high temperature and pressure to produce carbon monoxide and hydrogen syngas. After a period of reaction, carbon dioxide and water vapor in the gas phase will also undergo a reforming reaction with the natural gas in the dome, producing carbon monoxide and hydrogen. This will further increase the effective component ratio of the syngas.

[0100] Step Six: After the gas phase in Step Five has fully reacted, and the sensible heat has been recovered through the tubular gas heat exchanger, its temperature is acceptable to the hot coal gas cyclone dust collector 6. After treatment by the hot coal gas cyclone dust collector 6, the dust content will be reduced to 20g / m³. 3 about;

[0101] Step 7: The gas after dust removal can be used as the reducing gas of COREX pre-reduction shaft furnace 9 or, together with the top gas of COREX pre-reduction shaft furnace 9, can be washed and purified by the first scrubbing tower 7 and the first scrubbing tower 8 before being used as output gas. The dust is then blown back into the COREX melting gasifier 1.

[0102] In the method described in this embodiment, the methane conversion rate is 99.6-100%, the carbon monoxide yield is 89.2-90.2%, the hydrogen yield is 65.8-66.2%, the acetylene yield is 0.04-1.20%, and the syngas contains approximately 45% carbon monoxide and approximately 55% hydrogen.

[0103] Example 5

[0104] A method for preparing syngas using the dome of a COREX melt gasification furnace, the main equipment and components involved are as follows: Figure 1 As shown, the system includes a COREX molten gasifier 1, a tubular gas heat exchanger 2, a natural gas pressure regulating valve 3, an oxygen pressure regulating valve 4, an oxygen / natural gas coaxial mixed-injection burner 5, a hot coal gas cyclone dust collector 6, a scrubbing tower 7, a scrubbing tower 8, a COREX pre-reduction vertical shaft furnace 9, and a coal bunker 10. The dome area of ​​the COREX molten gasifier is the cavity above the semi-coke fixed bed in the molten gasifier. The burners consist of 6 oxygen burners and 4 circulating dust injection burners, with 6 of the 6 oxygen burners modified into oxygen / natural gas coaxial mixed-injection burners 5.

[0105] A method for preparing syngas using the dome of a COREX melt gasifier, the specific steps of which are as follows:

[0106] Step 1: Select natural gas and oxygen as raw materials, and introduce them into the natural gas pressure regulating valve 3 and oxygen pressure regulating valve 4 through the corresponding gas supply pipelines to increase the pressure to 390 kPa;

[0107] Step 2: The natural gas and oxygen after the pressure was increased in Step 1 are respectively introduced into the tubular gas heat exchanger 2 connected to the natural gas pressure regulating valve 3 and the oxygen pressure regulating valve 4 for preheating to 420℃.

[0108] Step 3: The preheated natural gas and oxygen from Step 2 are transported to the COREX melting gasification furnace (part of the oxygen is used for injection into the lower part of the furnace, such as...). Figure 1 (Illustrated), the oxygen / natural gas is mixed and injected into the dome area through the oxygen / natural gas coaxial mixing burner 5, wherein the volume ratio of oxygen to natural gas is 0.65, and the injection ratio of natural gas and oxygen can be effectively adjusted through the natural gas pressure regulating valve 3 and the oxygen pressure regulating valve 4;

[0109] Step 4: In the dome area, oxygen and natural gas mix rapidly under the action of high-speed airflow. A small portion of the natural gas will undergo a complete combustion reaction with the oxygen, releasing a large amount of heat. The local ignition temperature can reach 1800-2300℃. At the same time, the rising furnace gas carries the heat generated by the combustion of coal in the lower semi-coke fixed bed into the dome area. Under the combined effect of the two, a high temperature of about 1130℃ will be generated in the dome area.

[0110] Step 5: The unreacted natural gas from Step 4 will continue to undergo a non-catalytic partial oxidation reaction with oxygen under high temperature and pressure to produce carbon monoxide and hydrogen syngas. After a period of reaction, carbon dioxide and water vapor in the gas phase will also undergo a reforming reaction with the natural gas in the dome, producing carbon monoxide and hydrogen. This will further increase the effective component ratio of the syngas.

[0111] Step Six: After the gas phase in Step Five has fully reacted, and the sensible heat has been recovered through the tubular gas heat exchanger, its temperature is acceptable to the hot coal gas cyclone dust collector 6. After treatment by the hot coal gas cyclone dust collector 6, the dust content will be reduced to 20g / m³. 3 about;

[0112] Step 7: The gas after dust removal can be used as the reducing gas of COREX pre-reduction shaft furnace 9 or, together with the top gas of COREX pre-reduction shaft furnace 9, can be washed and purified by the first scrubbing tower 7 and the first scrubbing tower 8 before being used as output gas. The dust is then blown back into the COREX melting gasifier 1.

[0113] In the method described in this embodiment, the methane conversion rate is 99.6-100%, the carbon monoxide yield is 89.6-90.2%, the hydrogen yield is 66.0-66.2%, the acetylene yield is 0.04-1.20%, and the syngas contains approximately 45% carbon monoxide and approximately 55% hydrogen.

[0114] Example 6

[0115] A method for preparing syngas using the dome of a COREX melt gasification furnace, the main equipment and components involved are as follows: Figure 1 As shown, the system includes a COREX molten gasifier 1, a tubular gas heat exchanger 2, a natural gas pressure regulating valve 3, an oxygen pressure regulating valve 4, an oxygen / natural gas coaxial mixed-injection burner 5, a hot coal gas cyclone dust collector 6, a scrubbing tower 7, a scrubbing tower 8, a COREX pre-reduction vertical shaft furnace 9, and a coal bunker 10. The dome area of ​​the COREX molten gasifier is the cavity above the semi-coke fixed bed in the molten gasifier. The burners consist of 6 oxygen burners and 4 circulating dust injection burners, with 6 of the 6 oxygen burners modified into oxygen / natural gas coaxial mixed-injection burners 5.

[0116] A method for preparing syngas using the dome of a COREX melt gasifier, the specific steps of which are as follows:

[0117] Step 1: Select natural gas and oxygen as raw materials, and introduce them into the natural gas pressure regulating valve 3 and oxygen pressure regulating valve 4 through the corresponding gas supply pipelines to increase the pressure to 400 kPa;

[0118] Step 2: The natural gas and oxygen after the pressure was increased in Step 1 are respectively introduced into the tubular gas heat exchanger 2 connected to the natural gas pressure regulating valve 3 and the oxygen pressure regulating valve 4 and preheated to a temperature of 450℃.

[0119] Step 3: The preheated natural gas and oxygen from Step 2 are transported to the COREX melting gasification furnace (part of the oxygen is used for injection into the lower part of the furnace, such as...). Figure 1 (Illustrated), the oxygen / natural gas is mixed and injected into the dome area through the oxygen / natural gas coaxial mixing burner 5, wherein the volume ratio of oxygen to natural gas is 0.7, and the injection ratio of natural gas and oxygen can be effectively adjusted through the natural gas pressure regulating valve 3 and the oxygen pressure regulating valve 4;

[0120] Step 4: In the dome area, oxygen and natural gas mix rapidly under the action of high-speed airflow. A small portion of the natural gas will undergo a complete combustion reaction with the oxygen, releasing a large amount of heat. The local ignition temperature can reach 1800-2300℃. At the same time, the rising furnace gas carries the heat generated by the combustion of coal in the lower semi-coke fixed bed into the dome area. Under the combined effect of the two, a high temperature of about 1150℃ will be generated in the dome area.

[0121] Step 5: The unreacted natural gas from Step 4 will continue to undergo a non-catalytic partial oxidation reaction with oxygen under high temperature and pressure to produce carbon monoxide and hydrogen syngas. After a period of reaction, carbon dioxide and water vapor in the gas phase will also undergo a reforming reaction with the natural gas in the dome, producing carbon monoxide and hydrogen. This will further increase the effective component ratio of the syngas.

[0122] Step Six: After the gas phase in Step Five has fully reacted, and the sensible heat has been recovered through the tubular gas heat exchanger, its temperature is acceptable to the hot coal gas cyclone dust collector 6. After treatment by the hot coal gas cyclone dust collector 6, the dust content will be reduced to 20g / m³. 3 about;

[0123] Step 7: The gas after dust removal can be used as the reducing gas of COREX pre-reduction shaft furnace 9 or, together with the top gas of COREX pre-reduction shaft furnace 9, can be washed and purified by the first scrubbing tower 7 and the first scrubbing tower 8 before being used as output gas. The dust is then blown back into the COREX melting gasifier 1.

[0124] In the method described in this embodiment, the methane conversion rate is 99.6-100%, the carbon monoxide yield is 89.9-90.2%, the hydrogen yield is 66.0-66.2%, the acetylene yield is 0.04-1.20%, and the syngas contains approximately 45% carbon monoxide and approximately 55% hydrogen.

[0125] The present invention proposes a method for preparing syngas using the dome of a COREX molten gasifier, which can solve the technical problems in the prior art that are not conducive to the non-catalytic partial oxidation of natural gas, such as reactor material and space, catalyst addition, and coal or pulverized coal addition. At the same time, it solves the technical problem of obviously recovering and reusing the syngas produced in this process, and improves the conversion rate and thermal energy utilization rate of syngas.

[0126] This invention utilizes the dome region of a COREX molten gasifier to perform a non-catalytic partial oxidation reaction, which not only meets the high requirements of the reactor for heat resistance, but also allows for effective control of the reaction environment in the dome region. The control method is convenient and has the advantages of low cost and low pollution.

[0127] The dome area of ​​the COREX melting gasifier of this invention has a high-pressure environment and high-speed airflow. The reaction of the raw material gas is controlled by the oxygen / natural gas burners and the circulating dust injection burners to produce high-quality syngas and significantly improve the quality of the reducing gas produced by the COREX melting gasifier. This is beneficial to improving the reduction effect of the COREX pre-reduction vertical furnace and enhancing the quality of the pre-reduction product.

[0128] This invention achieves heat exchange between the gas pipeline at the arch outlet and the oxygen and natural gas pipelines by installing a heat exchanger, which uses an external heat transfer medium to achieve heat transfer between the pipelines and thus achieves heat exchange of the flowing gas. At the same time, the COREX process does not require the separation of some gas for cooling and purification before adding it to the hot gas at the arch outlet, thus improving the thermal energy utilization rate.

[0129] The syngas prepared by the non-catalytic partial oxidation in the COREX melt gasification furnace of this invention has high industrial value, a wide range of applications, high yields of hydrogen and carbon monoxide in the syngas, low heat energy consumption, and high heat energy utilization rate, making it suitable for industrial production practice.

[0130] In summary, compared with other traditional methods, the method of this invention adopts a reforming reaction technology solution of non-catalytic partial oxidation of natural gas with natural gas, water vapor, and carbon dioxide, which is not found in the prior art. Through the structural design of oxygen / natural gas burners and circulating dust injection burners, the structural design of heat exchangers, and the control of the composition of raw gas, combined with the high-pressure environment and high-speed gas flow in the dome area of ​​the COREX molten gasifier, good kinetic conditions are provided for the non-catalytic partial oxidation reaction of natural gas. The method is simple to operate, has low production cost, high efficiency, and is conducive to large-scale industrial production and promotion.

[0131] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A process for producing synthesis gas using a COREX melter gasifier roof, characterized in that, The method involves installing a heat exchanger between the coal gas pipeline at the outlet of the COREX molten gasifier dome and the oxygen and natural gas pipelines. The heat exchanger recovers the high-temperature sensible heat of the coal gas at the dome and uses it for preheating the oxygen and natural gas. The dome area of ​​the COREX molten gasifier is used as the reaction zone, and the preheated oxygen and natural gas are used as feed gas. The gas is injected into the dome area through the burners at the dome of the COREX molten gasifier to carry out a non-catalytic partial oxidation reaction of methane, thereby producing syngas with hydrogen and carbon monoxide as the main components. Oxygen and natural gas need to be pressurized and preheated by a heat exchanger before being injected into the vault area.

2. The process for producing synthesis gas using COREX melter gasifier dome according to claim 1, characterized in that, The COREX melting gasifier is a reactor in the COREX system that completes the melting and separation of sponge iron into molten iron and the production of reducing gas required for the reducing shaft furnace. Its dome area is the cavity above the semi-coke fixed bed of the melting gasifier.

3. The process for producing synthesis gas using COREX melter gasifier dome as claimed in claim 1, wherein, The heat exchanger is a ceramic shell-and-tube heat exchanger with a heat exchange efficiency of over 92%.

4. The method for preparing syngas using the dome of a COREX melting gasifier according to claim 1, characterized in that, The volume ratio of oxygen to natural gas in the raw gas is 0.5-0.7, and it is supplied via pipeline; the methane content of the natural gas reaches more than 90%, and the oxygen is industrial pure oxygen.

5. The process for producing synthesis gas using COREX melter gasifier dome as claimed in claim 1, wherein, Pressurize until the pressure reaches 300-450 kPa, and preheat the temperature to 100-450℃.

6. The process for producing synthesis gas using COREX melter gasifier dome as claimed in claim 1, wherein, The flow rate of oxygen and natural gas of the raw material gas into the vault is 4000-7000 Nm 3 / h and 8000-10000 Nm 3 / h.

7. The process for producing synthesis gas using COREX melter gasifier dome as claimed in claim 1, wherein the process is carried out at a temperature in the range of 1250-1350°C. The reaction time for non-catalytic partial oxidation is 0.004-0.008 s.

8. The method for preparing syngas using the dome of a COREX melting gasifier according to claim 1, characterized in that, The average temperature in the dome area of ​​the molten gasifier is 1050-1150℃, and the temperature of the generated gas is 1100±10℃.

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