CN216891062U - Production system for using natural gas for gas-based direct reduced iron - Google Patents
Production system for using natural gas for gas-based direct reduced iron Download PDFInfo
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Abstract
The utility model provides a production system for using natural gas for gas-based direct reduced iron, which comprises the following components: a preheating device; the natural gas pre-conversion reactor is connected with the outlet of the preheating device; and the direct reduced iron system is connected with the outlet of the natural gas pre-conversion reactor. The natural gas production system for the gas-based direct reduced iron provided by the utility model is generally exothermic reaction, is beneficial to reducing the load of gas heating in the subsequent direct reduced iron flow, and increases the total amount of converted effective gas. By high content of C2 +Natural gas and water vapor with component content in the converterReacting to obtain high-temperature natural gas which meets the technical requirements of gas-based direct reduced iron and has the function of reducing C2 +The risk of carbon deposition reaction, the content and the total amount of methane are improved, and the energy consumption in the heating process is reduced.
Description
Technical Field
The utility model belongs to the technical field of natural gas pretreatment in the field of metallurgy, relates to a production system of natural gas for gas-based direct reduced iron, and particularly relates to a method for producing high-C natural gas2+The natural gas with the components is used for a production system of gas-based direct reduced iron.
Background
With the global greenhouse effect becoming more serious, the global iron-making industry is conducting CO2And (4) emission reduction work. In this context, the gas-based direct reduced iron process uses low-carbon natural gas instead of coke, thereby significantly reducing carbon emissions and drawing industrial attention. The gas-based direct reduced iron refers to a method for producing metallic iron by performing a reduction reaction with oxidized pellets or iron ore at a temperature below the melting temperature of the iron ore by using a reducing gas such as hydrogen and/or carbon monoxide. The product can be directly used for electric furnaces, converters and blast furnaces. In this process, natural gas is reformed at high temperature to produce CO and H2The main reducing gas is raw natural gas which is a widely used reducing gas production source. Wherein the high-temperature reforming refers to the reaction of natural gas with steam and/or CO under the action of a catalyst2A reaction is carried out, which reaction produces CO and H2. Process for directly reducing iron in natural gas by gas base2 +(referring to hydrocarbon gases other than methane in natural gas) content is desirable, too high of C2 +The components easily cause carbon deposition reaction in the gas reforming and heating processes, and the carbon deposition is solid and can be continuously accumulated, so that the components of the reducing gas are influenced, and equipment cannot be continuously produced. By consulting the relevant international standard (SN/T2491-2010) Different from the Chinese national standard (GB19204-2020), natural gas has a great difference in composition, such as LNG (liquefied Natural gas), C2 +The component content has a wide variation range exceeding that of the direct reduced iron process pair C2 +The requirements of the components. Thus, if C is to be used2 +The natural gas with high component content needs to be pre-converted to meet the requirements of the direct reduced iron process, which has important significance for effective utilization of the natural gas in the direct reduced iron process.
For pretreatment of natural gas, the current process generally uses water and CO in the natural gas2And C2 +The components are removed by deep cooling, and temperature reduction and rise are needed, so as to remove C2 +The components are separated from the methane component. Or the natural gas is firstly subjected to steam reforming, the steam content in the reformed gas is high, the gas needs to be cooled and dehydrated, and secondary heating is needed in the subsequent direct reduced iron process flow, so that the energy utilization efficiency is relatively low. The two schemes have the problems of long process flow, high energy consumption, high investment and the like.
Therefore, how to find a treatment system for natural gas directly used for direct reduced iron, which improves energy utilization efficiency and ensures continuous and stable operation of natural gas used for a direct reduced iron production system has become one of the problems to be solved by related production enterprises in the field.
SUMMERY OF THE UTILITY MODEL
In view of the above, the technical problem to be solved by the present invention is to provide a natural gas production system for gas-based direct reduced iron, especially a system for producing high-C content natural gas2+The natural gas with the components is used for a system for gas-based direct reduced iron, and the obtained high-temperature natural gas which meets the technical requirements of the gas-based direct reduced iron has the advantages of controlling carbon deposition reaction, improving the content and the total amount of methane and reducing energy consumption in the heating process.
The utility model provides a production system for using natural gas for gas-based direct reduced iron, which comprises the following components:
a preheating device;
the natural gas pre-conversion reactor is connected with the outlet of the preheating device;
and the direct reduced iron system is connected with the outlet of the natural gas pre-conversion reactor.
Preferably, the preheating device comprises a preheating furnace and/or a heat exchange device;
the outlet of the preheating device comprises a preheating steam outlet and a preheating mixed gas outlet.
Preferably, the outlet of the preheated mixed gas is connected with the natural gas pre-conversion reactor.
Preferably, the preheating steam outlet is communicated with a raw natural gas pipeline before preheating.
Preferably, the direct reduced iron system comprises a metallurgical shaft furnace;
the metallurgical shaft furnace is connected with an outlet of the natural gas pre-conversion reactor.
Preferably, a reheating device and/or a reforming conversion device is/are further included between the outlet of the natural gas pre-conversion reactor and the direct reduced iron system.
Preferably, the reforming conversion apparatus comprises a tubular reformer.
Preferably, the flue of the convection section of the reforming conversion device is provided with a heat exchange device to preheat water vapor.
Preferably, a flue of the convection section of the reforming conversion device is provided with a heat exchange device to preheat a raw material mixed gas of raw material natural gas and steam.
Preferably, the heat of the preheating device comes from the sensible heat of the subsequent natural gas conversion high-temperature flue gas.
The utility model provides natural gas for gas-based direct reduced iron, which is characterized in that C in the natural gas for gas-based direct reduced iron2 +The molar content of (A) is less than 0.1%;
the methane mole content of the natural gas for the gas-based direct reduced iron is more than 84%.
Preferably, the temperature of the natural gas for gas-based direct reduced iron is 380-550 ℃;
in the natural gas for gas-based direct reduction of iron, CO2And H2The total molar content of O is less than 10%.
Preferably, the natural gas for gas-based direct reduced iron is obtained by converting raw natural gas;
c in the raw natural gas2 +The molar content of (A) is more than or equal to 10%;
compared with the raw material natural gas, the methane mole content of the natural gas for directly reducing iron by gas base is increased by 19-52%.
Preferably, the conversion is an exothermic reaction process;
the temperature of the natural gas for the gas-based direct reduced iron is increased by 1-63 ℃ compared with the temperature of the raw material natural gas before treatment;
the volume of the natural gas for the gas-based direct reduced iron is 115-140% of the volume of the raw material natural gas before treatment under the same pressure.
The utility model provides a preparation method of natural gas for gas-based direct reduced iron, which comprises the following steps:
1) preheating a mixed gas of raw material natural gas and steam to obtain a preheated mixed gas;
2) and (3) carrying out conversion reaction on the preheated mixed gas obtained in the step to obtain the natural gas for gas-based direct reduced iron.
Preferably, the feed natural gas comprises high C2 +Content of raw natural gas;
the temperature of the raw material natural gas is 10-40 ℃;
c in the raw material natural gas2 +The molar ratio of hydrocarbon carbon to water vapor is 1: (0.5 to 1.2).
Preferably, the temperature of the preheated mixed gas is 350-500 ℃;
the temperature of the water vapor is 350-500 ℃;
the water vapor comprises preheated water vapor.
Preferably, the conversion reaction also comprises a pressurizing step before;
the pressure of the pressurized preheated mixed gas is 0.9-1.2 MPaG;
the conversion reaction is a reaction in which the effective volume of natural gas is increased.
Preferably, the catalyst for the conversion reaction comprises a metal-noble metal composite catalyst;
the conversion reaction is exothermic.
Preferably, the temperature of the conversion reaction is 380-550 ℃;
the carbon airspeed of the conversion reaction is 500-2000 h-1；
And after the conversion reaction, the temperature of the obtained natural gas for the gas-based direct reduced iron is 380-550 ℃.
The utility model provides a production system for using natural gas for gas-based direct reduced iron, which comprises the following components: a preheating device; the natural gas pre-conversion reactor is connected with the outlet of the preheating device; and the direct reduced iron system is connected with the outlet of the natural gas pre-conversion reactor. Compared with the prior art, the prior natural gas pre-conversion treatment process has the defects that the steam content in the reformed gas is high, the pressure is too high, and both the steam content and the pressure exceed the requirement range of gas-based reduced iron. The gas is further subjected to cooling dehydration and/or decarburization treatment, and secondary heating and pressure reduction are also performed in the subsequent direct reduced iron process flow, which results in energy loss and relatively low energy utilization efficiency. And the process flow is increased, the energy consumption is high, the investment is high and the like.
The utility model designs a production system for applying natural gas to gas-based direct reduced iron, and C in the prepared natural gas2 +Less than 0.1% by mole, and methane more than 84% by mole, and has a relatively high temperature. The natural gas with the components meeting the requirements can be directly used in the gas-based direct iron reduction process, and has the advantages of controlling the converted carbon deposition reaction, improving the total amount of methane and reducing the energy consumption in the heating process.
The utility model provides a high-content C2 +The natural gas of the composition is used for gas after being pre-convertedA production system and a method of base direct reduced iron, which is to lead high C content2 +The natural gas of the components is converted and used for a production system of gas-based direct reduced iron, and C is added2 +Introducing natural gas with high component content and steam into a preheating furnace for heating, and then converting the preheated mixed gas in a heat-insulating converter to obtain the natural gas meeting the subsequent conversion and utilization requirements, and the natural gas can be directly used for producing reducing gas by gas-based direct reduced iron. The overall conversion reaction is exothermic, the temperature of the converted natural gas is higher than that of the raw material natural gas of the preheated mixed steam, and the load of gas heating in the subsequent direct reduction iron flow is reduced; moreover, the conversion reaction is overall volume increase reaction, and the effective gas amount after conversion is increased. The utility model adopts the high C content2 +The reaction of the natural gas and the water vapor in the adiabatic converter to obtain the high-temperature natural gas which meets the technological requirements of the gas-based direct reduced iron has the advantages of controlling carbon deposition reaction, improving the total amount of methane and reducing energy consumption in the heating process.
The results of the study show that, under the given gas composition conditions, for C2 +Natural gas and C in the raw material of 10-15-20%2 +Preheating the mixture and water vapor to 350-500 ℃ according to the ratio of 1: 0.5-1: 1.2, wherein the total carbon space velocity is 500-2000 h under the pressure of 0.9-1.2 MPaG-1In the range of, product gas, CH, after adiabatic conversion4Content greater than 84%, (CO)2+H2O) less than 10%, C2 +The content is less than 0.1 percent, the temperature of the process gas is increased to a certain extent (1-63 ℃), and the subsequent process requirements of the direct reduced iron are met. Increase in volume and temperature after reaction, CH4The content is increased, the effective gas content can be increased, and the heating energy consumption of the subsequent procedure is saved.
Drawings
FIG. 1 is a schematic diagram of a production system for producing natural gas for gas-based direct reduced iron according to the present invention;
fig. 2 is a schematic process flow diagram of the process for preparing natural gas for gas-based direct reduced iron provided by the utility model.
Detailed Description
For a further understanding of the utility model, preferred embodiments of the utility model are described below in conjunction with the examples, but it should be understood that these descriptions are included merely to further illustrate the features and advantages of the utility model and are not intended to limit the utility model to the claims.
All of the starting materials of the present invention, without particular limitation as to their source, may be purchased commercially or prepared according to conventional methods well known to those skilled in the art.
All the raw materials of the present invention are not particularly limited in purity, and the present invention preferably employs industrial pure or purity conventional in the field of gas-based direct reduced iron.
All the noun expressions and acronyms of the utility model belong to the conventional noun expressions and acronyms in the field, each noun expression and acronym is clearly and definitely clear in the relevant application field, and a person skilled in the art can clearly, exactly and uniquely understand the noun expressions and acronyms.
The utility model provides a production system for using natural gas for direct reduced iron, which comprises:
a preheating device;
the natural gas pre-conversion reactor is connected with the outlet of the preheating device;
and the direct reduced iron system is connected with the outlet of the natural gas pre-conversion reactor.
In the present invention, the preheating means preferably comprises a preheating furnace and/or a heat exchange means.
In the present invention, the outlet of the preheating device preferably includes a preheating steam outlet and a preheating mixed gas outlet, and the purpose of the preheating device is to preheat the steam for the first time and then preheat the mixed gas of the steam and the raw natural gas again.
In the present invention, the preheated mixed gas outlet is preferably connected to the natural gas pre-reforming reactor.
In the present invention, the preheated steam outlet is preferably communicated with a raw natural gas pipeline before preheating. The method aims to mix preheated steam with raw natural gas to obtain mixed gas and then introduce the mixed gas into a preheating device. Specifically, the raw natural gas pipeline before preheating is preheated by the preheating device, and then is connected with an outlet of the preheating device, so as to enter the natural gas pre-conversion reactor.
The heat of the preheating device comes from the sensible heat of the subsequent natural gas converted high-temperature flue gas.
In the present invention, the direct reduced iron system preferably comprises a metallurgical shaft furnace.
In the present invention, the metallurgical shaft furnace is preferably connected to the outlet of the natural gas pre-reforming reactor.
In the present invention, the metallurgical shaft furnace is preferably connected to the outlet of the natural gas pre-reforming reactor.
In the present invention, it is preferable that a reheating apparatus and/or a reforming conversion apparatus is further included between the outlet of the natural gas pre-reforming reactor and the direct reduced iron system.
In the present invention, the reforming conversion apparatus preferably comprises a tubular reformer.
In the utility model, the flue of the convection section of the reforming conversion device is preferably preheated by water vapor through a heat exchange device.
In the utility model, the flue of the convection section of the reforming conversion device is preferably used for preheating raw material mixed gas of raw material natural gas and steam through a heat exchange device.
Referring to fig. 1, fig. 1 is a schematic view of a production system for producing natural gas for gas-based direct reduced iron according to the present invention. Wherein, 1 is a natural gas pre-conversion reactor, 2 is a preheating device, 3 is a tubular converter, 4 is a direct reduced iron system, 5 is a water vapor source storage and conveying device, and 6 is a raw material natural gas storage and conveying device.
The utility model provides natural gas for gas-based direct reduced iron, which is characterized in that C in the natural gas for gas-based direct reduced iron2 +The molar content of (A) is less than 0.1%;
the natural gas for the gas-based direct reduced iron has a methane molar content of 84% or more.
In the utility model, C in the natural gas for gas-based direct reduced iron2 +The molar content of (b) is less than 0.1%, more preferably 0.08% or less, and still more preferably 0.05% or less.
In the present invention, the content (by mole) of methane in the natural gas for gas-based direct reduction of iron is 85% or more, more preferably 85% or more, and still more preferably 86% or more.
In the utility model, the temperature of the natural gas for the gas-based direct reduced iron is preferably 380-550 ℃, more preferably 400-530 ℃, more preferably 420-510 ℃, and more preferably 450-480 ℃.
In the present invention, in the natural gas for gas-based direct reduction of iron, CO2And H2The total molar content of O is preferably 10% or less, more preferably 8% or less, and still more preferably 5% or less.
In the present invention, C in the raw natural gas2 +Preferably greater than 10%, more preferably greater than 15%, more preferably greater than 20%.
In the present invention, the methane molar content of the natural gas for gas-based direct reduction of iron is preferably increased by 19% to 52%, more preferably by 31% to 52%, and still more preferably by 49% to 52% as compared with the raw natural gas.
In the utility model, the natural gas for the gas-based direct reduced iron is obtained by preferably converting raw natural gas.
In the present invention, the raw natural gas preferably includes Liquefied Natural Gas (LNG).
In the present invention, the treatment is preferably an exothermic reaction process.
In the utility model, the temperature of the natural gas for gas-based direct reduced iron is preferably increased by 1-63 ℃, more preferably increased by 15-63 ℃, and more preferably increased by 25-63 ℃ compared with the temperature of the raw material natural gas before treatment.
In the present invention, the volume of the natural gas for gas-based direct reduced iron is preferably 115 to 140%, more preferably 125 to 140%, and still more preferably 135 to 140% of the volume of the raw material natural gas before treatment.
The utility model also provides a preparation method of the natural gas for gas-based direct reduced iron, which comprises the following steps:
1) preheating a mixed gas of raw material natural gas and steam to obtain a preheated mixed gas;
2) and (3) carrying out conversion reaction on the preheated mixed gas obtained in the step to obtain the natural gas for gas-based direct reduced iron.
The method comprises the steps of preheating a mixed gas of raw material natural gas and steam to obtain a preheated mixed gas.
In the present invention, the feed natural gas preferably comprises high C2+Content of raw natural gas. In particular, liquefied natural gas may be used.
In the utility model, the temperature of the raw material natural gas is preferably 10-40 ℃, more preferably 15-35 ℃, and more preferably 20-30 ℃.
In the utility model, C in the raw natural gas2 +Amount of (in terms of C)2Molar content conversion) and water vapor is preferably 1: (0.5 to 1.2), more preferably 1: (0.7 to 1.2), more preferably 1: (0.9-1.2). In the present invention, the total hydrocarbon carbon, i.e., hydrocarbons (including methane and C) contained in natural gas2 +Etc.) of all hydrocarbons, and the steam, i.e., the steam contains H in terms of the number of C atoms2The number of moles of O.
In the utility model, the temperature of the water vapor is preferably 350-500 ℃, more preferably 400-500 ℃, and more preferably 450-500 ℃.
In the present invention, the water vapor includes preheated water vapor.
In the utility model, the temperature of the preheated mixed gas is preferably 350-500 ℃, more preferably 400-500 ℃, and more preferably 450-500 ℃.
The utility model further carries out conversion reaction on the preheated mixed gas obtained in the step to obtain the natural gas for gas-based direct reduced iron.
In the present invention, the conversion reaction preferably includes a pressurization step before the conversion reaction.
In the present invention, the pressure of the pressurized preheated mixed gas is preferably 0.9 to 1.2MPaG, more preferably 0.95 to 1.15MPaG, and still more preferably 1.0 to 1.1 MPaG.
In the present invention, the conversion reaction is preferably a reaction in which the effective volume of natural gas is increased.
In the present invention, the catalyst for the conversion reaction includes a metal noble metal composite catalyst, more preferably a high-activity carbon deposit resistant metal noble metal composite catalyst. Specifically, the catalyst for the conversion reaction may be a nickel palladium @ aluminum noble metal catalyst, and more specifically, a metal noble metal composite catalyst which takes Ni and Pd as active centers and takes a magnesium aluminate spinel system as a carrier is preferred.
In the present invention, the conversion reaction is preferably an exothermic reaction.
In the utility model, the temperature of the conversion reaction is preferably 380-550 ℃, more preferably 400-530 ℃, more preferably 420-510 ℃, and more preferably 450-480 ℃.
In the utility model, the time of the conversion reaction is preferably 5-10 min, more preferably 6-9 min, and more preferably 7-8 min.
In the utility model, the carbon space velocity of the conversion reaction is selected to be 500-2000 h-1More preferably 500 to 1500 hours-1More preferably 500 to 1000 hours-1。
In the utility model, after the conversion reaction, the temperature of the obtained natural gas for the gas-based direct reduced iron is preferably 380-550 ℃, more preferably 400-530 ℃, more preferably 420-510 ℃, and more preferably 450-480 ℃.
The utility model provides a high-content C2 +A method for directly reducing iron with natural gas containing components comprises preheating C in a preheating furnace2 +Preheating mixed gas of natural gas with high component content and steam; then the preheated natural gas and the steam enter an adiabatic reformer together, and finally the converted high-temperature natural gas meeting the requirement can be directly used for the production flow of the gas-based direct reduced iron.
In particular, the natural gas of the feedstock includes all of the natural gas having a higher C content2 +Natural gas of composition to achieve high C content2 +The natural gas with the components is effectively utilized in the gas-based direct reduced iron process.
In the present invention, the steam is preferably heated together with the natural gas, and more preferably, the steam is preheated first and then is preheated together with the natural gas. The water vapor and the natural gas are preheated together, so that the high C content can be effectively avoided2 +The coking problem of the raw material natural gas with component content in the preheating process.
In the present invention, the mixture of natural gas and steam is pressurized and then introduced into the reformer, and the inlet pressure may be determined according to the outlet pressure and the pressure loss.
C in the treated natural gas2 +The content of the components is less than 0.1 percent. And the content and the total amount of methane in the treated natural gas are increased compared with the natural gas before conversion. CO in natural gas after simultaneous treatment2And H2The content of O is low, and the total content is not more than 10%. In particular, the temperature of the treated natural gas is higher than the pre-heating temperature before reforming.
Referring to fig. 2, fig. 2 is a schematic diagram of a process flow for preparing natural gas for gas-based direct reduced iron according to the present invention.
The high C provided by the steps of the utility model2 +The method of using natural gas with components in gas-based direct reduced iron project can effectively reduce C in natural gas2 +Component (b) of (C), increasing CH4The content and the total amount of (methane) reduce the occurrence of carbon deposition reaction; the gas CO treated by the device or the method2And H2The content of O is low, the temperature of the converted gas is higher than the preheating temperature before the conversion, the temperature reaches about 500 ℃, and the high-temperature converted gas can be directly used for the subsequent processDirect reduction iron process. The preparation method and the production system can effectively utilize high C2 +Natural gas such as LNG and the like, and reduces the loss of equipment and catalyst in the production of the direct reduced iron and reduces the energy consumption in the production of the direct reduced iron.
The steps of the utility model provide a method for reducing high C2 +The natural gas with the components is used for the production system and the method of the gas-based direct reduced iron. The utility model designs a production system for applying natural gas to gas-based direct reduced iron, and C in the prepared natural gas2 +Less than 0.1% by mole, and methane more than 84% by mole, and has a relatively high temperature. The natural gas with the components meeting the requirements can be directly used in the gas-based direct iron reduction process, and has the advantages of controlling the converted carbon deposition reaction, improving the total amount of methane and reducing the energy consumption in the heating process.
The utility model provides a high-content C2 +The production system and method for gas-based direct reduced iron by pre-converting natural gas with components are used for producing high-C content direct reduced iron2 +The natural gas of the components is converted and used for a production system of gas-based direct reduced iron, and C is added2 +Introducing natural gas with high component content and steam into a preheating furnace for heating, and then converting the preheated mixed gas in a heat-insulating converter to obtain the natural gas meeting the subsequent conversion and utilization requirements, and the natural gas can be directly used for producing reducing gas by gas-based direct reduced iron. The overall conversion reaction is exothermic, the temperature of the converted natural gas is higher than that of the raw material natural gas of the preheated mixed steam, and the load of gas heating in the subsequent direct reduction iron flow is reduced; moreover, the conversion reaction is a volume-increasing reaction as a whole, and the amount of the effective gas after the conversion increases. The utility model adopts the high C content2 +The reaction of the natural gas and the water vapor in the adiabatic converter to obtain the high-temperature natural gas which meets the technological requirements of the gas-based direct reduced iron has the advantages of controlling carbon deposition reaction, improving the total amount of methane and reducing energy consumption in the heating process.
The results of the study show that, under the given gas composition conditions, for C2 +Natural gas and C in the raw material of 10-15-20%2 +Preheating the mixture and water vapor to 350-500 ℃ according to the ratio of 1: 0.5-1: 1.2, wherein the total carbon space velocity is 500-2000 h under the pressure of 0.9-1.2 MPaG-1In the range of, product gas, CH, after adiabatic conversion4Content greater than 84%, (CO)2+H2O) less than 10%, C2 +The content is less than 0.1 percent, the temperature of the process gas is increased to a certain extent (1-63 ℃), and the subsequent process requirements of the direct reduced iron are met. Increase in volume and temperature after reaction, CH4The content is increased, the effective gas content can be increased, and the heating energy consumption of the subsequent procedure is saved.
To further illustrate the present invention, a system and a method for producing gas-based direct reduced iron according to the present invention will be described in detail with reference to the following examples, but it should be understood that the present invention is not limited to the following examples, and that the present invention is not limited to the following examples.
Examples
The utility model provides a production system for using natural gas for gas-based direct reduced iron, which comprises a preheating device, a natural gas pre-conversion reactor connected with an outlet of the preheating device and a direct reduced iron system, namely a metallurgical shaft furnace, connected with an outlet of the natural gas pre-conversion reactor.
Wherein, the preheating device comprises a preheating furnace and a heat exchange device. And the outlet of the preheating device comprises a preheating steam outlet and a preheating mixed gas outlet, the preheating mixed gas outlet is connected with the natural gas pre-conversion reactor, and the preheating steam outlet is communicated with a raw material natural gas pipeline before preheating.
The metallurgical shaft furnace is connected with an outlet of the natural gas pre-conversion reactor.
In addition, the heat of the preheating device can be directly heated by heating equipment (such as the initial start of the production system or the unstable state of the production system), and can also come from the sensible heat of the subsequent natural gas converted high-temperature flue gas (such as the normal operation of the production system).
Specifically, a reheating device and a reforming conversion device, namely a tubular converter, are arranged between the outlet of the natural gas pre-conversion reactor and the direct reduced iron system.
Wherein, the flue of the convection section of the reforming conversion device is provided with a second heat exchange device, and the steam is preheated by the second heat exchange device.
Furthermore, a third heat exchange device is arranged in a flue of the convection section of the reforming conversion device, and the raw material mixed gas of the raw material natural gas and the steam is preheated through the third heat exchange device.
Referring to fig. 1, fig. 1 is a schematic view of a production system for producing natural gas for gas-based direct reduced iron according to the present invention. Wherein, 1 is a natural gas pre-conversion reactor, 2 is a preheating device, 3 is a tubular converter, 4 is a direct reduced iron system, 5 is a water vapor source storage and conveying device, and 6 is a raw material natural gas storage and conveying device.
The production system for applying natural gas to gas-based direct reduced iron provided by the utility model is adopted to carry out subsequent experiments.
Example 1
Using a certain LNG as a raw material, C2 +Content-15% and composition N2 0.11％，CH4 84.71％，C2H6 12.33％，C3H8 2.64％，C4H10 0.21％。
Raw natural gas according to C2 +Mixing with water vapor at a ratio of 1:1, further preheating to 400 deg.C under a pressure of 1.1MPaG and a carbon space velocity of 1000h-1Under the conditions, the process gas composition and temperature before and after adiabatic reforming are shown in table 1, where table 1 shows the process gas composition and temperature before and after adiabatic reforming.
TABLE 1
After transformationThe temperature of the process gas is increased by 32 ℃, the absolute amount of methane is increased by 28mol, and the relative amount is increased by 33%. The content of methane is 89 percent based on the converted unit gas, C2+ content 0.01%, oxidizing gas (CO)2+H2O) content is 7.5 percent.
Example 2
Starting with the LNG of example 1, the feed natural gas is as per C2 +Mixing with water vapor at a ratio of 1:1, further preheating to 450 deg.C under a pressure of 1.0MPaG and a carbon space velocity of 500h-1Under the conditions, the process gas composition and temperature before and after adiabatic reforming are shown in table 2, where table 2 shows the process gas composition and temperature before and after adiabatic reforming.
TABLE 2
The temperature of the converted process gas rises by 16 ℃, the absolute amount of methane is increased by 27mol, and the relative amount is increased by 32%. The content of methane is 88 percent based on the converted unit gas, C2+ content 0.01%, oxidizing gas (CO)2+H2O) content is 7.1 percent.
Example 3
Starting with the LNG of example 1, the feed natural gas is as per C2 +Mixing with water vapor at a ratio of 1:0.5, further preheating to 400 deg.C under a pressure of 1.0MPaG and a carbon space velocity of 1500 hr-1Under the conditions, the process gas composition and temperature before and after adiabatic reforming are shown in Table 3, where Table 3 shows the process gas composition and temperature before and after adiabatic reforming.
TABLE 3
The temperature of the converted process gas rises by 20 ℃, the absolute amount of methane is increased by 27mol, and the relative amount is increased by 32%. Calculated by converted unit gas, the content of methane is 95 percent, C2+ content 0.09%, oxidizing gas (CO)2+H2O) content is 1.8 percent.
Example 4
Starting with the LNG of example 1, the feed natural gas is as per C2 +Mixing with water vapor at a ratio of 1:1.2, further preheating to 450 deg.C under a pressure of 1.1MPaG and a carbon space velocity of 2000h-1Under the conditions, the process gas composition and temperature before and after adiabatic reforming are shown in Table 4, where Table 4 shows the process gas composition and temperature before and after adiabatic reforming.
TABLE 4
The temperature of the converted process gas rises to 13 ℃, the absolute amount of methane is increased to 27mol, and the relative amount is increased to 32%. Calculated by converted unit gas, the content of methane is 85 percent, C2+ content of 0.01%, oxidizing gas (CO)2+H2O) content is 9.1 percent.
Example 5
Adopting natural gas of a certain pipeline as a raw material, wherein the raw material natural gas is according to C2 +Content ~ 10%, C2 +Mixing with water vapor at a ratio of 1:1, further preheating to 350 deg.C under a pressure of 1.0MPaG and a carbon space velocity of 1000h-1Under the conditions, the process gas composition and temperature before and after adiabatic reforming are shown in table 5, where table 5 shows the process gas composition and temperature before and after adiabatic reforming.
TABLE 5
The temperature of the converted process gas rises by 30 ℃, the absolute quantity of methane is increased by 18mol, and the relative quantity is increased by 21%. Calculated by converted unit gas, the content of methane is 92 percent, C2+ content 0.01%, oxidizing gas (CO)2+H2O) content is 5.6 percent.
Example 6
The natural gas of example 5 was used as feed, feed natural gas C2 +Mixing with water vapor 1:1, and further mixingPreheating to 400 ℃ at the pressure of 1.1MPaG and the carbon space velocity of 1500h-1Under the conditions, the process gas composition and temperature before and after adiabatic reforming are shown in Table 6, and Table 6 shows the process gas composition and temperature before and after adiabatic reforming.
TABLE 6
The temperature of the converted process gas rises by 20 ℃, the absolute amount of methane is increased by 18mol, and the relative amount is increased by 20%. The content of methane is 92 percent and C is calculated by converted unit gas2+ content 0.01%, oxidizing gas (CO)2+H2O) content is 5.6 percent.
Example 7
Using associated gas of a certain oil field as a raw material, and C in the raw material gas2 +Content-20% according to C2 +Mixing with water vapor at a ratio of 1:1, further preheating to 350 deg.C under a pressure of 1.2MPaG and a carbon space velocity of 1000h-1Under the conditions, the process gas composition and temperature before and after adiabatic reforming are shown in Table 7, and Table 7 shows the process gas composition and temperature before and after adiabatic reforming.
TABLE 7
The temperature of the converted process gas rises to 62 ℃, the absolute amount of methane is increased to 40mol, and the relative amount is increased to 51%. The content of methane is 88 percent based on the converted unit gas, C2+ content 0.01%, oxidizing gas (CO)2+H2O) content is 9.1 percent.
Example 8
Starting from example 7, according to C2 +Mixing with water vapor at a ratio of 1:1, further preheating to 500 deg.C under a pressure of 0.9MPaG and a carbon space velocity of 2000h-1Under the conditions, the process gas composition and temperature before and after adiabatic reforming are shown in Table 8, where Table 8 shows the process gas composition and temperature before and after adiabatic reforming.
TABLE 8
The temperature of the converted process gas rises by 7 ℃, the absolute amount of methane is increased by 38mol, and the relative amount is increased by 49 mol. Calculated by converted unit gas, the content of methane is 84 percent, C2+ content 0.02%, oxidizing gas (CO)2+H2O) content is 7.7 percent.
The utility model provides a high C2+The detailed description of the system for producing gas-based direct reduced iron using natural gas as a constituent is given herein using specific examples to explain the principles and embodiments of the present invention, and the above examples are only given to help understand the method of the present invention and its core ideas, including the best mode, and also to enable any person skilled in the art to practice the utility model, including making and using any device or system, and implementing any combined method. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention. The scope of the utility model is defined by the claims and may include other embodiments that occur to those skilled in the art. Such other embodiments are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.
Claims (7)
1. A system for using natural gas for producing gas-based direct reduced iron, comprising:
a preheating device;
the outlet of the preheating device comprises a preheating steam outlet and a preheating mixed gas outlet;
the natural gas pre-conversion reactor is connected with the outlet of the preheating device;
the preheating mixed gas outlet is connected with the natural gas pre-conversion reactor;
the preheating steam outlet is communicated with a raw natural gas pipeline before preheating;
a direct reduced iron system connected to the outlet of the natural gas pre-reforming reactor;
the direct reduced iron system comprises a metallurgical shaft furnace;
the metallurgical shaft furnace is connected with an outlet of the natural gas pre-conversion reactor.
2. The production system of claim 1, wherein the preheating device comprises a preheating furnace and/or a heat exchange device.
3. The production system of claim 1, further comprising a reheating device and/or a reforming conversion device between the outlet of the natural gas pre-reforming reactor and the direct reduced iron system.
4. The production system of claim 3, wherein said reforming reformer comprises a tubular reformer.
5. The production system of claim 3, wherein the flue of the convection section of the reforming unit is preheated by a heat exchange unit.
6. The production system of claim 3, wherein the flue of the convection section of the reforming conversion device is provided with a heat exchange device to preheat the raw mixed gas of raw natural gas and steam.
7. The production system of claim 1, wherein the preheater heat is derived from the sensible heat of a subsequent natural gas conversion high temperature flue gas.
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