Zero-carbon emission hydrogen-ammonia electrofusion steel rolling heating furnace system and control method

Abstract

This invention discloses a zero-carbon emission hydrogen-ammonia-electricity fusion steel rolling furnace system and control method. It includes a liquid ammonia storage tank, electronic flow valve, vaporizer, decomposition furnace, variable frequency fan, burner gas distribution system, burner, electric radiant tubes, condenser, and chimney. After vaporization in the vaporizer, a portion of the ammonia gas is directly distributed to the burner for combustion via the burner gas distribution system, while the other portion is catalytically decomposed into nitrogen and hydrogen in the decomposition furnace, and then distributed to the burner for combustion via the burner gas distribution system. Hydrogen is more flammable, burns faster, and has a higher calorific value than ammonia, enabling stable ignition and combustion of the ammonia. The advantages of this invention are that the preheating section uses electric radiant tubes for heating, increasing the use of green electricity in the steel rolling furnace; the heating and soaking sections use a mixture of hydrogen and ammonia for combustion, solving the problems of difficult ignition and slow combustion when using only ammonia, which is of great significance for improving the comprehensive utilization of ammonia energy.

Description

Technical Field

[0001] This invention relates to the field of steel rolling heating furnace system technology, specifically to a zero-carbon emission hydrogen-ammonia-electric fusion steel rolling heating furnace system and control method. Background Technology

[0002] Major economies around the world have successively formulated corresponding carbon emission reduction targets and plans.

[0003] Electricity generated by wind and solar energy is called green electricity. Using small-scale electric radiant tubes in steel rolling furnaces is one way to save energy and reduce emissions. Hydrogen is one of the cleanest energy sources, but it is expensive to produce and difficult to store and transport. Ammonia is a good carrier for hydrogen energy. Compared to hydrogen, ammonia's main advantages are its high hydrogen content and high volumetric energy density; liquid ammonia even has a higher hydrogen content and volumetric energy density per unit volume than liquid hydrogen. Furthermore, due to its mature production process, easy liquefaction for storage and transportation, and high safety, it is considered a more promising clean fuel and can effectively serve as a carrier for hydrogen and energy. However, ammonia has poor combustion characteristics, is difficult to ignite, and burns slowly. Mixing hydrogen and ammonia for combustion can solve this problem.

[0004] Existing technologies for the fusion of hydrogen, ammonia, and electricity are mostly concentrated in internal combustion engines or power plant boiler burners. There are virtually no applications of this technology in steel rolling heating furnaces. Furthermore, existing steel rolling heating furnace systems primarily use natural gas, coal gas, and hydrogen as fuels. Using natural gas and coal gas as fuels results in significant carbon emissions, while using hydrogen as fuel would substantially increase production costs. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a zero-carbon emission hydrogen-ammonia-electric fusion steel rolling heating furnace system and control method to address the shortcomings of the existing technology, which can achieve both zero carbon emissions and control reasonable production costs.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0007] I. A zero-carbon emission hydrogen-ammonia-electric fusion steel rolling heating furnace system

[0008] This invention provides a zero-carbon emission hydrogen-ammonia-electric fusion steel rolling heating furnace system, including a liquid ammonia storage tank 1, an electronic flow valve 2, a vaporizer 3, a decomposition furnace 4, a variable frequency fan 5, an electric radiation tube 6, a burner gas distribution system 7, a burner 8, an ammonia separator 9, a condenser 10, and a chimney 11.

[0009] The liquid ammonia storage tank 1 is connected to the first input end of the vaporizer 3 via a liquid ammonia pipeline. An electronic flow valve 2 is installed on the liquid ammonia pipeline. The first output end of the vaporizer 3 is directly connected to the first input end of the burner gas distribution system 7. The second output end of the vaporizer 3 is connected to the first input end of the decomposition furnace 4 via a second pipeline. The first output end of the decomposition furnace 4 is connected to the second input end of the burner gas distribution system 7. The third input end of the burner gas distribution system 7 is connected to air via a variable frequency fan 5. Multiple output ends of the burner gas distribution system 7 are respectively connected to multiple sets of burners 8 in the rolling mill heating furnace. The flue gas pipeline of the rolling mill heating furnace is connected to the second input end of the decomposition furnace 4. The second output end of the decomposition furnace 4 is connected to the second input end of the vaporizer 3. The second output end of the vaporizer 3 is connected to the chimney 11 after passing through an ammonia separator 9 and a condenser 10 in sequence.

[0010] Preferably, the multiple sets of burners 8 are located in the heating section and the soaking section of the steel rolling furnace, and the preheating section of the steel rolling furnace is equipped with an electric radiation tube 6.

[0011] Preferably, the electric radiant tube 6 is powered by a wind or solar generator.

[0012] Preferably, the heating temperature of the electric radiant tube 6 is 800-900℃.

[0013] Preferably, the decomposition furnace 4 is equipped with a specially made catalyst with high surface area and high nickel content.

[0014] Preferably, the ammonia separator 9 is equipped with an ammonia adsorbent.

[0015] Preferably, the first input end of the burner gas distribution system 7 is directly connected to the vaporizer 3 through an ammonia input pipe, the second input end of the burner gas distribution system 7 is connected to the decomposition furnace 4 through a hydrogen-nitrogen mixed gas input pipe, and the third input end of the burner gas distribution system 7 is connected to the variable frequency fan 5 through an air input pipe.

[0016] Preferably, an igniter 8-1 is provided at the center of the burner 8, a primary air duct 8-2 is provided around the igniter 8-1, a hydrogen-nitrogen mixture duct 8-3 is provided around the primary air duct 8-2, a secondary air duct 8-4 is provided around the hydrogen-nitrogen mixture duct 8-3, and an ammonia duct 8-5 is provided around the secondary air duct 8-4.

[0017] Preferably, the primary air pipe 8-2 and the secondary air pipe 8-4 are both connected to the air output end of the burner gas distribution system 7, the hydrogen-nitrogen mixture pipe 8-3 is connected to the hydrogen-nitrogen mixture output end of the burner gas distribution system 7, the ammonia pipe 8-5 is connected to the ammonia output end of the burner gas distribution system 7, and the gas output of the ammonia pipe 8-5 is more than twice the gas output of the hydrogen-nitrogen mixture pipe 8-3.

[0018] II. A Control Method for a Zero-Carbon Emission Hydrogen-Ammonia-Electric Fusion Steel Rolling Heating Furnace System

[0019] Based on the same inventive concept, this invention also provides a zero-carbon emission hydrogen-ammonia-electric fusion steel rolling furnace system control method, which uses the steel rolling furnace system described above and specifically includes the following steps:

[0020] S1, Ammonia preparation: Liquid ammonia in the liquid ammonia storage tank is transported to the vaporizer and vaporized into ammonia by the waste heat of high-temperature flue gas. A preset amount of ammonia is directly sent to the burner gas distribution system, while a preset amount of ammonia is sent to the decomposition furnace.

[0021] S2, ammonia is decomposed into a hydrogen-nitrogen mixture. The ammonia in the decomposition furnace is decomposed into hydrogen and nitrogen by the nickel catalyst and the waste heat of the high-temperature flue gas provided by the furnace. The hydrogen and nitrogen are then sent to the burner gas distribution system.

[0022] S3, Air Pump In, the variable frequency fan pumps a preset amount of combustion air into the burner gas distribution system;

[0023] S4, the burner gas distribution system distributes the input ammonia, hydrogen-nitrogen mixture and combustion air to multiple sets of burners in the heating section and soaking section of the rolling mill heating furnace according to a preset ratio for combustion, and at the same time turns on the electric radiant tubes in the preheating section of the rolling mill heating furnace.

[0024] In this case, the proportion of ammonia in a single burner is more than twice that of a hydrogen-nitrogen mixture;

[0025] S5, waste heat utilization of flue gas: the high-temperature flue gas generated by combustion in the steel rolling heating furnace is sequentially transported to the decomposition furnace and vaporizer through the flue gas pipeline for waste heat utilization.

[0026] S6 separates unburned ammonia. After the waste heat of the flue gas is used up, it enters the ammonia separator, where unburned ammonia is captured by an adsorbent.

[0027] S7, the flue gas after ammonia separation is condensed by the condenser and then discharged through the chimney.

[0028] Compared with the prior art, the present invention has the following main advantages:

[0029] 1. This invention utilizes the waste heat of high-temperature flue gas from a steel rolling furnace to heat the vaporizer and decomposition furnace, vaporizing and decomposing liquid ammonia to obtain fuels such as ammonia and hydrogen. Multi-nozzle burners are used for mixed combustion in the heating and soaking sections of the furnace, and electric radiant tubes are arranged in the preheating section of the steel rolling furnace. Power is supplied by wind or solar energy, enabling the steel rolling furnace to achieve zero carbon emissions and control reasonable production costs.

[0030] 2. By using the waste heat of flue gas to heat the decomposition furnace and vaporizer, liquid ammonia is vaporized and decomposed to obtain ammonia and hydrogen mixed for combustion. This not only improves the utilization efficiency of waste heat of flue gas, but also solves the problem of poor combustion characteristics of ammonia, and can reduce production costs.

[0031] 3. The preheating section uses electric radiant tube heating, which can increase the use of green electricity in the steel rolling heating furnace. The heating section and soaking section use a mixture of hydrogen and ammonia for combustion, which solves the problems of difficult ignition and slow combustion speed when using ammonia alone, and is of great significance for improving the comprehensive utilization of ammonia energy. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the overall rolling mill heating furnace system in an embodiment of the present invention;

[0033] Figure 2 This is a cross-sectional view of the burner in an embodiment of the present invention;

[0034] Figure 3 This is a flowchart of the control method in an embodiment of the present invention.

[0035] In the diagram: 1. Liquid ammonia storage tank; 2. Electronic flow valve; 3. Vaporizer; 4. Decomposition furnace; 5. Variable frequency fan; 6. Radiant tube; 7. Burner gas distribution system; 8. Burner; 9. Ammonia separation device; 10. Condenser; 11. Chimney; 8-1. Ignition device; 8-2. Primary air pipeline; 8-3. Hydrogen-nitrogen mixture pipeline; 8-4. Secondary air pipeline; 8-5. Ammonia pipeline. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0037] It should be noted that, depending on the implementation needs, the various steps / components described in this application can be broken down into more steps / components, or two or more steps / components or parts of the operation of steps / components can be combined into new steps / components to achieve the purpose of this invention.

[0038] Example 1: This example provides a zero-carbon emission hydrogen-ammonia-electric fusion steel rolling heating furnace system, such as... Figures 1-2 As shown, it mainly includes a liquid ammonia storage tank 1, an electronic flow valve 2, a vaporizer 3, a decomposition furnace 4, a variable frequency fan 5, an electric radiant tube 6, a burner gas distribution system 7, a burner 8, an ammonia separator 9, a condenser 10, and a chimney 11, etc.

[0039] The electric radiation tube 6 is arranged in the preheating section of the heating furnace, and the burner 8 is arranged in the heating section and the homogenization section of the heating furnace. The liquid ammonia storage tank 1 is connected to the vaporizer 3 through a pipeline, and the pipeline is equipped with an electronic flow valve 2 to control the flow rate of liquid ammonia.

[0040] After liquid ammonia is vaporized into ammonia gas by vaporizer 3, part of the ammonia gas is directly distributed to the corresponding burner 8 for combustion via burner gas distribution system 7, and the other part of the ammonia gas is catalytically decomposed into nitrogen and hydrogen gas by decomposition furnace 4, and then distributed to the corresponding burner 8 for combustion via burner gas distribution system 7. Combustion air is pumped into burner gas distribution system 7 by variable frequency fan 5 according to the actual combustion flow rate required, and then distributed to each burner 8. The flue gas generated after combustion is used for waste heat utilization in decomposition furnace 4 and vaporizer 3 in sequence, then unburned ammonia gas is separated in ammonia gas separator 9, then condensed in condenser 10, and finally discharged through chimney 11.

[0041] in:

[0042] 1) The vaporizer is heated internally by a flue gas duct, and the waste heat of the flue gas is used to vaporize the liquid ammonia.

[0043] The decomposition furnace is equipped with a specially designed high-surface-area, high-nickel catalyst. The flue gas temperature from the heating furnace is 850-900℃, which is just enough to provide the temperature required for the decomposition reaction to decompose ammonia into a mixture of hydrogen and nitrogen.

[0044] First, the high surface area and high nickel catalyst inside the decomposition furnace provides the temperature required for the decomposition reaction, decomposing ammonia into a mixture of hydrogen and nitrogen. Then, the flue gas passes through a vaporizer to vaporize the liquid ammonia.

[0045] 2) The burner gas distribution system is connected to the air pipeline, the ammonia pipeline and the pipeline from the decomposition furnace, and then the gas in the three pipelines is distributed to each burner.

[0046] 3) The burner includes an igniter 8-1, a primary air pipe 8-2, a hydrogen and nitrogen mixture pipe 8-3, a secondary air pipe 8-4, and an ammonia pipe 8-5. The igniter is located at the center of the primary air pipe, and the hydrogen and nitrogen mixture pipes are distributed around the primary air pipes. The secondary air pipes are distributed around the hydrogen and nitrogen mixture pipes, and the ammonia pipes are distributed on the outermost side of the burner.

[0047] The air in the primary air pipe 8-2 and the secondary air pipe 8-4 provides combustion support for the hydrogen in the hydrogen-nitrogen mixture pipe 8-3 and the ammonia in the ammonia pipe 8-5. Hydrogen has excellent combustion characteristics and a high calorific value. The combustion of hydrogen inside the ammonia can provide a large amount of heat for the combustion of ammonia, thus driving the ammonia to burn completely.

[0048] 4) The fuel contains hydrogen, nitrogen and ammonia. During combustion, it will produce a high amount of NOx. It is necessary to add an excess of ammonia during combustion. The excess ammonia will reduce the NOx produced by combustion to nitrogen, thus avoiding the emission of NOx in the flue gas. The excess ammonia is separated by an ammonia separator along with the flue gas and then re-enters the heating furnace for combustion.

[0049] 5) The electric radiation heating tubes are arranged in the preheating section of the heating furnace, and the heating temperature is 800-900℃.

[0050] 6) The ammonia separator described above has good ammonia capture capability under low partial pressure and high temperature conditions. The adsorbent can selectively separate ammonia from NH3 / N2 and NH3 / H2O with high selectivity.

[0051] Example 2, based on the same inventive concept, also provides a zero-carbon emission hydrogen-ammonia-electric fusion steel rolling furnace system control method, employing the steel rolling furnace system as described above, such as... Figure 3 As shown, the specific steps include the following:

[0052] S1, Ammonia preparation: Liquid ammonia in the liquid ammonia storage tank is transported to the vaporizer and vaporized into ammonia by the waste heat of high-temperature flue gas. A preset amount of ammonia is directly sent to the burner gas distribution system, while a preset amount of ammonia is sent to the decomposition furnace.

[0053] S2, ammonia is decomposed into a hydrogen-nitrogen mixture. The ammonia in the decomposition furnace is decomposed into hydrogen and nitrogen by the nickel catalyst and the waste heat of the high-temperature flue gas provided by the furnace. The hydrogen and nitrogen are then sent to the burner gas distribution system.

[0054] S3, Air Pump In, the variable frequency fan pumps a preset amount of combustion air into the burner gas distribution system;

[0055] S4, the burner gas distribution system distributes the input ammonia, hydrogen-nitrogen mixture and combustion air to multiple sets of burners in the heating section and soaking section of the rolling mill heating furnace according to a preset ratio for combustion, and at the same time turns on the electric radiant tubes in the preheating section of the rolling mill heating furnace.

[0056] In this case, the proportion of ammonia in a single burner is more than twice that of a hydrogen-nitrogen mixture;

[0057] S5, waste heat utilization of flue gas: the high-temperature flue gas generated by combustion in the steel rolling heating furnace is sequentially transported to the decomposition furnace and vaporizer through the flue gas pipeline for waste heat utilization.

[0058] S6 separates unburned ammonia. After the waste heat of the flue gas is used up, it enters the ammonia separator, where unburned ammonia is captured by an adsorbent.

[0059] S7, the flue gas after ammonia separation is condensed by the condenser and then discharged through the chimney.

[0060] Furthermore, all parts of this application that are not described in detail are the same as or implemented using existing technology.

[0061] In summary:

[0062] 1. This invention utilizes the waste heat of high-temperature flue gas from a steel rolling furnace to heat the vaporizer and decomposition furnace, vaporizing and decomposing liquid ammonia to obtain fuels such as ammonia and hydrogen. Multi-nozzle burners are used for mixed combustion in the heating and soaking sections of the furnace, and electric radiant tubes are arranged in the preheating section of the steel rolling furnace. Power is supplied by wind or solar energy, enabling the steel rolling furnace to achieve zero carbon emissions and control reasonable production costs.

[0063] 2. By using the waste heat of flue gas to heat the decomposition furnace and vaporizer, liquid ammonia is vaporized and decomposed to obtain ammonia and hydrogen mixed for combustion. This not only improves the utilization efficiency of waste heat of flue gas, but also solves the problem of poor combustion characteristics of ammonia, and can reduce production costs.

[0064] 3. The preheating section uses electric radiant tube heating, which can increase the use of green electricity in the steel rolling heating furnace. The heating section and soaking section use a mixture of hydrogen and ammonia for combustion, which solves the problems of difficult ignition and slow combustion speed when using ammonia alone, and is of great significance for improving the comprehensive utilization of ammonia energy.

[0065] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A zero-carbon emission hydrogen-ammonia-electric fusion steel rolling heating furnace system, characterized in that, The system includes a liquid ammonia storage tank (1), which is connected to the first input end of a vaporizer (3) via a liquid ammonia pipeline. An electronic flow valve (2) is installed on the liquid ammonia pipeline. The first output end of the vaporizer (3) is directly connected to the first input end of a burner gas distribution system (7). The second output end of the vaporizer (3) is connected to the first input end of a decomposition furnace (4) via a second pipeline. The first output end of the decomposition furnace (4) is connected to the second input end of the burner gas distribution system (7). The third input end of the gas system (7) is connected to the air through a variable frequency fan (5). The multiple output ends of the burner gas distribution system (7) are respectively connected to multiple sets of burners (8) in the steel rolling heating furnace. The flue gas pipeline of the steel rolling heating furnace is connected to the second input end of the decomposition furnace (4). The second output end of the decomposition furnace (4) is connected to the second input end of the vaporizer (3). The second output end of the vaporizer (3) is connected to the chimney (11) after passing through the ammonia separator (9) and the condenser (10) in sequence.

2. The zero-carbon emission hydrogen-ammonia-electric fusion steel rolling heating furnace system according to claim 1, characterized in that, The multiple sets of burners (8) are located in the heating section and the soaking section of the steel rolling furnace, and the preheating section of the steel rolling furnace is equipped with electric radiation tubes (6).

3. The zero-carbon emission hydrogen-ammonia-electric fusion steel rolling heating furnace system according to claim 2, characterized in that, The electric radiant tube (6) is specifically powered by a wind or solar generator, and the heating temperature of the electric radiant tube (6) is 800-900℃.

4. The zero-carbon emission hydrogen-ammonia-electric fusion steel rolling heating furnace system according to claim 1, characterized in that, The decomposition furnace (4) is equipped with a nickel-containing catalyst with a preset surface area.

5. The zero-carbon emission hydrogen-ammonia-electric fusion steel rolling heating furnace system according to claim 1, characterized in that, The ammonia separator (9) is equipped with an ammonia adsorbent.

6. The zero-carbon emission hydrogen-ammonia-electric fusion steel rolling heating furnace system according to claim 1, characterized in that, The first input end of the burner gas distribution system (7) is directly connected to the vaporizer (3) through an ammonia gas input pipe. The second input end of the burner gas distribution system (7) is connected to the decomposition furnace (4) through a hydrogen-nitrogen mixed gas input pipe. The third input end of the burner gas distribution system (7) is connected to the variable frequency fan (5) through an air input pipe.

7. The zero-carbon emission hydrogen-ammonia-electric fusion steel rolling heating furnace system according to claim 1, characterized in that, An igniter (8-1) is provided at the center of the burner (8). A primary air duct (8-2) is provided around the igniter (8-1). A hydrogen-nitrogen mixed gas duct (8-3) is provided around the primary air duct (8-2). A secondary air duct (8-4) is provided around the hydrogen-nitrogen mixed gas duct (8-3). An ammonia gas duct (8-5) is provided around the secondary air duct (8-4).

8. A zero-carbon emission hydrogen-ammonia-electric fusion steel rolling heating furnace system according to claim 7, characterized in that, The primary air duct (8-2) and the secondary air duct (8-4) are both connected to the air output end of the burner gas distribution system (7), the hydrogen-nitrogen mixed gas duct (8-3) is connected to the hydrogen-nitrogen mixed gas output end of the burner gas distribution system (7), and the ammonia gas duct (8-5) is connected to the ammonia gas output end of the burner gas distribution system (7).

9. A zero-carbon emission hydrogen-ammonia-electric fusion steel rolling heating furnace system according to claim 7, characterized in that, The ammonia gas pipeline (8-5) has an output volume that is more than twice that of the hydrogen-nitrogen mixed gas pipeline (8-3).

10. A control method for a zero-carbon emission hydrogen-ammonia-electric fusion steel rolling heating furnace system, employing the steel rolling heating furnace system as described in any one of claims 1 to 9, characterized in that, Includes the following steps: S1, Ammonia preparation: Liquid ammonia in the liquid ammonia storage tank is transported to the vaporizer and vaporized into ammonia by the waste heat of high-temperature flue gas. A preset amount of ammonia is directly sent to the burner gas distribution system, while a preset amount of ammonia is sent to the decomposition furnace. S2, ammonia is decomposed into a hydrogen-nitrogen mixture. The ammonia in the decomposition furnace is decomposed into hydrogen and nitrogen by the nickel catalyst and the waste heat of the high-temperature flue gas provided by the furnace. The hydrogen and nitrogen are then sent to the burner gas distribution system. S3, Air Pump In, the variable frequency fan pumps a preset amount of combustion air into the burner gas distribution system; S4, the burner gas distribution system distributes the input ammonia, hydrogen-nitrogen mixture and combustion air to multiple sets of burners in the heating section and soaking section of the rolling mill heating furnace according to a preset ratio for combustion, and at the same time turns on the electric radiant tubes in the preheating section of the rolling mill heating furnace. In this case, the proportion of ammonia in a single burner is more than twice that of a hydrogen-nitrogen mixture; S5, waste heat utilization of flue gas: the high-temperature flue gas generated by combustion in the steel rolling heating furnace is sequentially transported to the decomposition furnace and vaporizer through the flue gas pipeline for waste heat utilization. S6 separates unburned ammonia. After the waste heat of the flue gas is used up, it enters the ammonia separator, where unburned ammonia is captured by an adsorbent. S7, the flue gas after ammonia separation is condensed by the condenser and then discharged through the chimney.

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