A method for increasing the top gas temperature of a hydrogen-rich carbon circulating oxygen blast furnace

Abstract

The invention discloses a method for increasing the gas temperature at the top of a hydrogen-rich carbon circulating oxygen blast furnace. A combustion heat storage device for burning decarbonized coal gas is installed at the throat steel brick of the hydrogen-rich carbon circulating oxygen blast furnace. The combustion tube of the combustion heat storage device adopts high-speed airflow jet heating technology. The decarbonized coal gas and compressed air flow and mix in a certain proportion in the combustion tube, and are ignited and burned by an electronic spark device on the inner tube wall to form a stable heat source. 85-94% of the mixed gas is burned in the tube, and the rest is completely burned in the heat storage tube. A large amount of excess coal gas, flue gas and hot gas are ejected at a high speed of 110-250m / s, so that strong convection heat transfer is generated in the hydrogen-rich carbon circulating oxygen blast furnace, and due to the strong stirring of a large amount of gas, the mixing temperature of the low-temperature coal gas at the top of the hydrogen-rich carbon circulating oxygen blast furnace is uniform.

Description

Technical Field

[0001] The invention relates to a method for increasing the temperature of top gas in a hydrogen-rich carbon circulating oxygen blast furnace. Background Art

[0002] The hydrogen-rich carbon circulating oxygen blast furnace uses oxygen blast to replace the traditional preheated air blast, and removes CO2 from the top gas before recycling it for use. The recycling of the top gas increases the partial pressure of CO, enhances the reduction potential of the gas, strengthens the reduction of the iron-containing charge, reduces the direct reduction degree, improves the ironmaking production efficiency, reduces fuel consumption, and reduces carbon emissions. This process develops indirect reduction and reduces direct reduction. The top gas after removing CO2 has a higher concentration of reducing components (CO and H2), which increases the reduction potential in the furnace, develops indirect reduction, and reduces the fuel ratio. However, due to the use of pure oxygen blast, the amount of gas in the furnace is reduced. Due to the heat utilization efficiency of the entire furnace body, the flow field and temperature field in the furnace need to be optimized under the condition of circulating gas injection. However, through production practice parameters, the top temperature of the hydrogen-rich carbon circulating oxygen blast furnace is often low and is below 70°C for a long time. Too low top temperature will cause condensation and dust adhesion on the gas riser and downcomer, causing accidents of blocking the gas pipeline. In addition, the water vapor of the water-containing gas condenses and settles with the dust in the gas in the gravity dust collector, blocking the ash discharge channel at the bottom, causing the gas ash to compact in the lower cone section of the gravity dust collector, seriously affecting the normal production of the hydrogen-rich carbon circulating oxygen blast furnace. Summary of the invention

[0003] The object of the present invention is to provide a method for increasing the temperature of the top gas of a hydrogen-rich carbon circulating oxygen blast furnace, which can increase the temperature of the top gas of a hydrogen-rich carbon circulating oxygen blast furnace and ensure normal production.

[0004] The technical solution adopted by the present invention is: a method for increasing the top gas temperature of a hydrogen-rich carbon cycle oxygen blast furnace, a combustion heat storage device for burning decarbonized coal gas is installed at the throat steel brick of the hydrogen-rich carbon cycle oxygen blast furnace, the combustion heat storage device is divided into a combustion tube and a heat storage tube, 85-94% of the mixed gas is burned in the combustion tube, and the rest is completely burned in the heat storage tube. A large amount of excess coal gas, flue gas and hot gas are sprayed into the hydrogen-rich carbon cycle oxygen blast furnace at a high speed of 110-250m / s;

[0005] The end face of the combustion tube device is provided with a decarbonization gas burner, and the top face is provided with a compressed air burner and an electronic spark device. The decarbonization gas burner is connected and installed with a 0.5MPa decarbonization gas pipeline and a control system. The decarbonization gas control system is composed of a gas quick-cut valve, a regulating valve, a gate valve, and a pressure gauge. The decarbonization gas control system is also equipped with a nitrogen security purge system. The compressed air burner is connected and installed with a 0.6MPa compressed air pipeline and a control system. The compressed air pipeline and the control system are composed of a compressed air quick-cut valve, a regulating valve, a gate valve, and a pressure gauge. The compressed air pipeline and the control system are also equipped with a nitrogen security purge system. The controls of the above systems are all connected to the digital control system through cables;

[0006] The heat storage cylinder is cylindrical, with a combustion cylinder installed on the front end, a gas oxygen content detection device and an excess gas and smoke temperature detection device installed on the upper cylinder side, a circular refractory brick wall is built inside, and a honeycomb refractory heat storage masonry shorter than its axial dimension is arranged inside the brick wall, and the excess gas and smoke heat the brick wall and the internal empty heat storage masonry passing through the honeycomb refractory;

[0007] The decarbonized coal gas contains more than 65% CO. The decarbonized coal gas burner and the compressed air burner are mixed and burned at high speed in the combustion tube to produce 1200℃ excess coal gas and flue gas. The control of the decarbonized coal gas flow and compressed air is completed by establishing a 1.15 times excess coal gas coefficient through a digital computer, and automatically adjusting the opening of the regulating valve on the compressed air pipeline and the decarbonized coal gas control system; the usage range of decarbonized coal gas is 900-1100Nm 3 / h, the pressure is controlled at 0.5Mpa, and the amount of compressed air used ranges from 1400-1600Nm 3 / h, pressure controlled at 0.6Mpa, hydrogen-rich carbon circulating oxygen blast furnace top gas flow rate 80000Nm 3 / h, and the pressure is maintained at 0.16-0.18 Mpa; a gas oxygen content detection device is installed on the upper cylinder side of the heat storage cylinder to detect the oxygen content of excess gas and flue gas in real time and control it below 0.8%; an excess gas and flue gas temperature detection device is installed on the upper cylinder side of the heat storage cylinder to detect the excess gas and flue gas temperature in real time and control it at 1200℃.

[0008] The heat storage cylinder, brick wall and honeycomb refractory heat storage masonry of the present invention are heated by excess coal gas and flue gas, wherein the brick holes inside the honeycomb refractory heat storage masonry can pass high-temperature flue gas and store a certain amount of heat. The present invention mainly adopts a method of heating the furnace top gas by using partially decarbonized coal gas from the furnace top combustion to provide high-temperature flue gas or high-temperature flue gas with excess coal gas. Through this method, the furnace top gas can be raised from 70°C to 90-95°C, so that the moisture in the coal gas is not precipitated and is in a gaseous state. It passes through the coal gas riser, downcomer and gravity dust collector together with the coal gas and enters the double-text scrubber, and does not form crystal water before the double-text scrubber.

[0009] The key core technology of the present invention is to install a combustion heat storage device for burning decarbonized coal gas at the throat steel brick of the throat of the hydrogen-rich carbon circulating oxygen blast furnace, and use the combustion heat storage device to generate high-temperature excess coal gas and flue gas, the temperature of which is controlled at about 1200°C, and mixed with the 70°C low-temperature coal gas at the top of the furnace to heat the low-temperature coal gas at the top of the furnace to above 90°C. The combustion heat storage device is divided into a combustion tube and a heat storage tube. The combustion tube of the combustion heat storage device adopts high-speed airflow jet heating technology and is equipped with a high-speed burner. The decarbonized coal gas and compressed air flow and mix in a certain proportion in the combustion tube, and are ignited and burned by the electronic spark device on the inner tube wall to form a stable heat source. 85-94% of the mixed gas burns in the tube, and the rest is completely burned in the heat storage tube. A large amount of excess coal gas and flue gas hot gas is ejected at a high speed of 110 to 250 m / s, which generates strong convective heat transfer in the hydrogen-rich carbon circulating oxygen blast furnace. Due to the strong stirring of a large amount of gas, the mixing temperature of the low-temperature coal gas on the top of the hydrogen-rich carbon circulating oxygen blast furnace becomes uniform.

[0010] Compared with the prior art, the technical solution provided by the present invention has the beneficial effects of: it can make the top gas of the hydrogen-rich carbon circulating oxygen blast furnace rise from 70°C to 90-95°C, so that the moisture in the gas does not precipitate, and is in a gaseous state, and passes through the gas riser, downcomer, and gravity dust collector together with the gas into the Shuangwen scrubber, and does not form crystal water before the Shuangwen scrubber. A gas oxygen content detection device is installed on the upper cylinder side of the cylinder device to detect the oxygen content of excess gas and flue gas in real time, and control the decarbonized gas to below 0.8%, ensuring the safety of the gas. The decarbonized gas control system and the compressed air control system are also equipped with a nitrogen security purge system and a quick-cut valve to quickly cut off the connection between this system and the hydrogen-rich carbon circulating oxygen blast furnace in the event of a machine trip or emergency repair, ensuring safe production. The brick wall and honeycomb refractory heat storage masonry of the heat storage cylinder device store a certain amount of heat, which can be used as a safe ignition source for re-ignition after the burner is extinguished. In order to control the oxygen content for safety reasons, excess gas is burned to make the flue gas composition a reducing atmosphere, meeting the safety requirement that the oxygen content in the gas is less than 0.8%. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Attached Figure 1 It is a schematic diagram of the connection structure of the present invention;

[0012] Figure 2 for Figure 1 Side view of the internal air thermal storage masonry. Implementation

[0013] A method for increasing the temperature of the top gas of a hydrogen-rich carbon circulating oxygen blast furnace, such as Figure 1 , 2 As shown, a combustion heat storage device for burning decarbonized coal gas is installed at the throat steel brick of the hydrogen-rich carbon circulating oxygen blast furnace. The combustion heat storage device is divided into a combustion tube 2 and a heat storage tube 3. The combustion tube 2 of the combustion heat storage device adopts high-speed airflow jet heating technology and is provided with a high-speed burner. The decarbonized coal gas and compressed air flow and mix in a certain proportion in the combustion tube 2, and are ignited and burned by the electronic spark device 6 on the inner tube wall to form a stable heat source. 85-94% of the mixed gas is burned in the tube, and the rest is completely burned in the heat storage tube 3. A large amount of excess coal gas, flue gas and hot gas are ejected at a high speed of 110-250m / s, thus generating strong convective heat transfer in the hydrogen-rich carbon circulating oxygen blast furnace, and due to the strong stirring of a large amount of gas, the mixing temperature of the low-temperature coal gas on the top 1 of the hydrogen-rich carbon circulating oxygen blast furnace is made uniform;

[0014] The end face of the combustion tube device 2 is provided with a decarbonization gas burner 4, and the top face is provided with a compressed air burner 5 and an electronic spark device 6. The decarbonization gas burner 4 is connected and installed with a 0.5MPa decarbonization gas pipeline and a control system 7. The decarbonization gas control system 7 is composed of a gas quick-cut valve, a regulating valve, a gate valve, and a pressure gauge. The decarbonization gas control system 7 is also equipped with a nitrogen security purge system 10. The compressed air burner 5 is connected and installed with a 0.6MPa compressed air pipeline and a control system 8. The compressed air pipeline and the control system 8 are composed of a compressed air quick-cut valve, a regulating valve, a gate valve, and a pressure gauge. The compressed air pipeline and the control system 8 are also equipped with a nitrogen security purge system 11; the controls of the above systems are all connected to the digital control system 9 through cables;

[0015] The heat storage cylinder 3 is cylindrical, with a combustion cylinder 2 installed on the front end, a gas oxygen content detection device 12 and an excess gas and smoke temperature detection device 13 installed on the upper cylinder side, a circular refractory brick wall 14 is built inside, and a honeycomb refractory heat storage masonry 15 shorter than its axial dimension is arranged inside the brick wall 14, and the excess gas and smoke heat the brick wall 14 and the internal empty heat storage masonry 15 passing through the honeycomb refractory;

[0016] The decarbonized coal gas contains more than 65% CO. The decarbonized coal gas burner 4 and the compressed air burner 5 are mixed and burned at high speed in the combustion tube 2 to produce 1200℃ excess coal gas and flue gas. The control of the decarbonized coal gas flow and compressed air is completed by establishing a 1.15 times excess coal gas coefficient through a digital computer, and automatically adjusting the opening of the regulating valve on the compressed air pipeline and the decarbonized coal gas control system; the usage range of the decarbonized coal gas is 900-1100Nm 3 / h, the pressure is controlled at 0.5Mpa, and the amount of compressed air used ranges from 1400-1600Nm 3 / h, pressure controlled at 0.6Mpa, hydrogen-rich carbon circulating oxygen blast furnace top 1 gas flow 80000Nm 3 / h, and the pressure is maintained at 0.16-0.18 Mpa; a gas oxygen content detection device 12 is installed on the upper cylinder side of the heat storage cylinder 3 to detect the oxygen content of excess coal gas and flue gas in real time and control it below 0.8%; an excess coal gas and flue gas temperature detection device 13 is installed on the upper cylinder side of the heat storage cylinder 3 to detect the excess coal gas and flue gas temperature in real time and control it at 1200℃.

[0017] A large amount of excess coal gas and flue gas hot gas is ejected at a high speed of 110-250m / s, which generates strong convection heat transfer in the top space of the hydrogen-rich carbon circulating oxygen blast furnace. Due to the strong stirring of a large amount of gas, the mixing temperature of the low-temperature coal gas at the top of the hydrogen-rich carbon circulating oxygen blast furnace 1 is uniform, rising from 70°C to 90-95°C. Example

[0018] Hydrogen-rich carbon cycle oxygen blast furnace re-air production: Before closing the top ignition manhole, open the regulating valve of the compressed air burner 5 and turn on the electronic spark device 6 for ignition, then open the regulating valve of the decarbonized coal gas burner 4, and burn steadily with a small fire. At this time, the compressed air flow rate is controlled at 50 Nm 3 / h, the flow rate of decarbonized coal gas is controlled at 40 Nm 3 / h, prepare to open the air and close the top ignition manhole of the furnace. The hydrogen-rich carbon circulating oxygen blast furnace is in the stage of resuming production after opening the air. At this time, due to the reaction of the low load (a large amount of fuel coke) off-air material put into the hydrogen-rich carbon circulating oxygen blast furnace, the amount of coal gas at the furnace top is sufficient, and the temperature of the furnace top exceeds 90°C. With the adjustment of the furnace condition after opening the furnace, the gas utilization efficiency is improved, and the temperature of the furnace top tends to decrease. At this time, it is necessary to enter Example 2 to adjust the decarbonization coal gas flow rate of the compressed air flowmeter. Example

[0019] Normal production of hydrogen-rich carbon cycle oxygen blast furnace: the top gas flow rate of hydrogen-rich carbon cycle oxygen blast furnace is 80000m3 / h, the top temperature is lower than 70℃, the control of decarbonized gas flow rate and compressed air is established by digital computer with 1.15 times excess gas coefficient, and the excess gas and flue gas temperature detection device 13 is set to control it at 1200℃, combined with the comprehensive control of the top gas flow rate and temperature of hydrogen-rich carbon cycle oxygen blast furnace, at this time, the decarbonized gas flow rate and compressed air are automatically adjusted by computer through the opening of the regulating valve on the compressed air pipeline and the decarbonized gas control system, and the usage range of decarbonized gas is adjusted to 900-1100Nm 3 / h, the amount of compressed air used is adjusted to 1400-1600Nm 3 / h, so that the hydrogen-rich carbon circulating oxygen blast furnace top gas is heated to 90℃. When the oxygen content of coal gas flue gas exceeds 0.8%, it can be appropriately increased by 10-30 Nm 3 / h decarbonized coal gas volume. Example

[0020] The hydrogen-rich carbon circulating oxygen blast furnace is shut down and production is stopped: before shutting down the production, close the quick-cut valve of the compressed air burner 5 and the quick-cut valve of the decarbonization gas burner 4, and at the same time, open the decarbonization gas control system and the compressed air control system, and match the nitrogen security purge systems 10 and 11 to purge for 2 minutes, then close the purge valve.

Claims

1. A method for increasing the temperature of hydrogen-rich carbon circulating oxygen blast furnace top gas, characterized in that: A combustion heat storage device for burning decarbonized coal gas is installed at the throat steel brick of the hydrogen-rich carbon cycle oxygen blast furnace. The combustion heat storage device is divided into a combustion tube and a heat storage tube. 85-94% of the mixed gas is burned in the combustion tube, and the rest is completely burned in the heat storage tube. A large amount of excess coal gas and flue gas is sprayed into the hydrogen-rich carbon cycle oxygen blast furnace at a high speed of 110-250m / s. The end face of the combustion tube is provided with a decarbonization gas burner, and the top face is provided with a compressed air burner and an electronic spark device. The decarbonization gas burner is connected and installed with a 0.5MPa decarbonization gas pipeline and a decarbonization gas control system. The decarbonization gas control system is composed of a gas quick-cut valve, a regulating valve, a gate valve, and a pressure gauge. The decarbonization gas control system is also equipped with a nitrogen security purge system. The compressed air burner is connected and installed with a 0.6MPa compressed air control system. The compressed air control system is composed of a compressed air quick-cut valve, a regulating valve, a gate valve, and a pressure gauge. The compressed air control system is also equipped with a nitrogen security purge system. The controls of the above systems are all connected to the digital control system through cables; The heat storage cylinder is cylindrical, and a combustion cylinder is installed on its front end surface. A circular refractory brick wall is built inside the heat storage cylinder. A honeycomb refractory heat storage masonry body that is slightly shorter than its axial dimension is arranged inside the brick wall. Excess gas and smoke heat the brick wall and pass through the honeycomb refractory heat storage masonry body. The decarbonized coal gas contains more than 65% CO. The decarbonized coal gas sprayed by the decarbonized coal gas burner and the compressed air sprayed by the compressed air burner are mixed and burned at a high speed in the combustion tube to produce 1200°C excess coal gas and flue gas. The control of the decarbonized coal gas flow and the compressed air flow is completed by establishing a 1.15 times excess coal gas coefficient through a digital computer, and automatically adjusting the opening of the regulating valve on the compressed air control system and the decarbonized coal gas control system; the use range of the decarbonized coal gas is 900-1100Nm 3 / h, the pressure is controlled at 0.5MPa, and the amount of compressed air used ranges from 1400-1600Nm 3 / h, pressure controlled at 0.6MPa, hydrogen-rich carbon circulating oxygen blast furnace top gas flow rate 80000Nm 3 / h, the pressure is maintained at 0.16-0.18MPa; a gas oxygen content detection device is installed on the upper cylinder side of the heat storage cylinder to detect the oxygen content of excess gas and flue gas in real time and control it below 0.8%; a surplus gas and flue gas temperature detection device is installed on the upper cylinder side of the heat storage cylinder to detect the excess gas and flue gas temperature in real time and control it at 1200℃.

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