A high pressure gas-based shaft furnace process system

Abstract

The utility model discloses a kind of high-pressure gas-based shaft furnace process systems, comprising: pellet lockhopper 1, high-pressure shaft furnace 2, DRI buffer tank 3 and DRI lockhopper 4;Wherein pellet lockhopper 1 is located at the top of shaft furnace, receives iron ore material under high-pressure state and inputs high-pressure shaft furnace 2 under high-pressure state, high-pressure shaft furnace 2 connects pellet lockhopper 1 and the DRI buffer tank 3, and the DRI pellet obtained by reaction in the high-pressure shaft furnace 2 is discharged to the DRI buffer tank 3;DRI buffer tank 3 discharges DRI pellet to DRI lockhopper 4 under high-pressure state.By using the high-pressure gas-based shaft furnace process system provided by the utility model, the whole process of gas-based shaft furnace from feeding, in-furnace reaction to discharging is completed under high pressure, the reduction reaction rate is accelerated, the gas utilization rate is improved, the single-furnace production capacity is increased, thereby reducing production cost, saving energy consumption, improving the overall economy of shaft furnace technology.

Description

Technical Field

[0001] This utility model relates to the field of gas-based vertical furnace technology, and in particular to a high-pressure gas-based vertical furnace process system. Background Technology

[0002] Currently, the steel industry is developing towards a sustainable direction characterized by rational layout, advanced equipment, and green, low-carbon practices. Electric arc furnace (EAF) short-process steelmaking is one of the encouraged directions in the steel industry. Increasingly, scrap steel is being used as a steelmaking raw material, thereby increasing the production of direct reduced iron (DRI), promoting the development of non-blast furnace ironmaking, and providing strong technical and production support for the transformation and upgrading of large integrated steel enterprises.

[0003] However, the operating pressure of existing gas-based vertical shaft furnaces generally does not exceed 0.7 MPaG, resulting in large-scale equipment, long installation cycles, and high investment and construction costs. Furthermore, as a fixed-bed structure, the vertical shaft furnace has a long reaction time, is not sensitive to the reaction rate, and has low reducing gas utilization. Utility Model Content

[0004] The purpose of this invention is to provide a high-pressure gas-based vertical shaft furnace process system to at least partially solve the above-mentioned problems of the prior art.

[0005] To achieve the above objectives, this utility model provides a high-pressure gas-based vertical shaft furnace process system, comprising: a pellet lock hopper 1, a high-pressure vertical shaft furnace 2, a DRI buffer tank 3, and a DRI lock hopper 4; wherein

[0006] The pellet lock hopper 1 is located at the top of the vertical shaft furnace and includes a feed valve, a discharge valve, an air inlet, and a pressure relief valve. The air inlet is connected to the first pressurizing device. The pellet lock hopper 1 is used to receive iron ore pellets from the upper storage silo through the feed valve. When the level of iron ore pellets reaches a threshold, the feed valve is closed. Pressurized gas is received through the air inlet. When the gas pressure in the pellet lock hopper 1 is consistent with the gas pressure in the high-pressure vertical shaft furnace 2, pressurization is stopped. The discharge valve is opened to discharge the iron ore pellets into the high-pressure vertical shaft furnace 2. After the discharge is completed, the discharge valve is closed. The pressure relief valve is opened. When the gas pressure in the pellet lock hopper 1 is consistent with the gas pressure in the upper storage silo, the pressure relief valve is closed.

[0007] The high-pressure vertical furnace 2 is connected to the pellet lock hopper 1 and the DRI buffer tank 3, and the DRI pellets obtained from the reaction in the high-pressure vertical furnace 2 are discharged into the DRI buffer tank 3;

[0008] The DRI buffer tank 3 is connected to the DRI lock hopper 4 via a discharge valve;

[0009] The DRI hopper 4 includes a receiving valve, a discharging valve, a pressurizing port, and a depressurizing valve. The pressurizing port is connected to a second pressurizing device. The DRI hopper 4 is pressurized by the second pressurizing device. Pressurization is stopped when the air pressure in the DRI hopper 4 is consistent with that in the DRI buffer tank 3. The receiving valve is then opened to receive the DRI pellets from the DRI buffer tank 3. After receiving the pellets, the depressurizing valve is opened to release the pressure. The pressure release is stopped when the air pressure in the DRI hopper 4 is consistent with that of the downstream equipment. The discharging valve is then opened to discharge the DRI pellets.

[0010] Preferably, the pipe wall of the DRI buffer tank 3 includes, from the inside out, a wear-resistant lining layer, a refractory material layer, an equipment outer wall layer, a jacket water channel layer, and a jacket outer wall layer.

[0011] Preferably, the high-pressure vertical furnace 2 discharges the DRI pellets into the DRI buffer tank 3 through the high-pressure rotary discharge valve 19.

[0012] Preferably, the high-pressure vertical furnace 2 includes a sampler and a controller. The sampler samples in real time online, and the controller adjusts the gas temperature, gas composition, and / or gas flow rate inside the high-pressure vertical furnace 2 according to the sampling results.

[0013] Preferably, the high-pressure vertical furnace 2 is sequentially connected to the waste boiler 5 and the reducing gas preheater 6; the reducing gas preheater 6 includes a first channel connected to a reducing gas purification device, which outputs reducing gas treated by the waste boiler 5 to the reducing gas purification device; the reducing gas preheater 6 includes a second channel connected to the reducing gas purification device, which receives the reducing gas purified by the reducing gas purification device, and the purified reducing gas is preheated by the reducing gas in the first channel before being input into the high-pressure vertical furnace 2.

[0014] Preferably, the second channel of the reducing gas preheater 6 includes a heating furnace 18 between it and the high-pressure vertical furnace 2. The heating furnace 18 is also connected to the incoming fresh gas to heat the mixed fresh gas and the reducing gas.

[0015] Preferably, the waste boiler 5 is a shell-and-tube heat exchanger, the top gas output from the high-pressure vertical furnace 2 flows through the shell side, the boiler water flows through the tube side, and the boiler water is sent out of the boundary area through the steam generated by heat exchange with the top gas.

[0016] Preferably, the reducing gas purification equipment includes a reducing gas venturi 7, a reducing gas scrubbing tower 8, a reducing gas condenser separator 9, and a decarbonization device connected in sequence; the system also includes a compressor for compressing the pre-reduction gas processed by the reducing gas purification equipment to the reducing gas preheater 6.

[0017] Preferably, the bottom of the reducing gas scrubbing tower 8 is connected to a flash tank 12, the bottom of the flash tank 12 is connected to a settling tank 13, and the settling tank 13 is connected to an ash water tank 14 and a separation device 15; wherein, the ash water at the bottom of the reducing gas scrubbing tower 8 enters the flash tank 12, the black water after flashing in the flash tank 12 enters the settling tank 13 for gravity settling and solid-liquid separation, the overflow water at the top of the settling tank 13 enters the ash water tank 14, and the sludge at the bottom of the settling tank 13 is pumped to the separation device 15.

[0018] Preferably, the pressure reducing valve of the DRI lock hopper 4 is connected to the lock hopper depressurization gas venturi 16, and the lock hopper depressurization gas venturi 16 is connected to the lock hopper depressurization gas scrubbing tower 17.

[0019] Compared with the prior art, the present invention has at least the following advantages:

[0020] By adopting the high-pressure gas-based vertical shaft furnace process system provided by this utility model, high-pressure feeding of iron ore and high-pressure output of DRI pellets are achieved, enabling the entire process of the gas-based vertical shaft furnace from feeding and in-furnace reaction to discharge to be completed under high pressure. As the furnace pressure increases, the reduction reaction rate accelerates, the gas utilization rate improves, and the single-furnace production capacity increases, thereby reducing production costs, saving energy consumption, and improving the overall economic efficiency of vertical shaft furnace technology. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of a high-pressure gas-based vertical furnace process system provided for an embodiment of the present invention.

[0022] Figure 2 A schematic diagram of the pipe wall structure of the DRI buffer tank in the high-pressure gas-based vertical furnace process system provided in this embodiment of the utility model. Detailed Implementation

[0023] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0024] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate to understand the embodiments of the utility model described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a product or device comprising a series of units is not necessarily limited to those explicitly listed, but may include other units not explicitly listed or inherent to such product or device.

[0025] In this invention, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this invention and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0026] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this utility model according to the specific circumstances.

[0027] Furthermore, the terms "installation," "setup," "equipped with," "connection," "linking," and "socketing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this utility model based on the specific circumstances.

[0028] It should be noted that, where there is no conflict, the embodiments and features in the embodiments of this utility model can be combined with each other. The present utility model will now be described in detail with reference to the accompanying drawings and embodiments.

[0029] Example 1

[0030] This utility model embodiment provides a high-pressure gas-based vertical furnace process system. Figure 1 A schematic diagram of the system is shown. (Reference) Figure 1 As shown, the system includes a pellet lock hopper 1, a high-pressure vertical furnace 2, a DRI buffer tank 3, and a DRI lock hopper 4; wherein...

[0031] The pellet lock hopper 1 is located at the top of the vertical shaft furnace and includes a feed valve, a discharge valve, an air inlet, and a pressure relief valve. The air inlet is connected to the first pressurizing device. The pellet lock hopper 1 is used to receive iron ore pellets from the upper storage bin through the feed valve. When the level of iron ore pellets reaches the threshold, the feed valve is closed, and pressurized gas is received through the air inlet. When the gas pressure in the pellet lock hopper 1 is consistent with the gas pressure in the high-pressure vertical shaft furnace 2, pressurization is stopped, the discharge valve is opened, and the iron ore pellets are discharged into the high-pressure vertical shaft furnace 2. After the discharge is completed, the discharge valve is closed, and the pressure relief valve is opened. When the gas pressure in the pellet lock hopper 1 is consistent with the gas pressure in the upper storage bin, the pressure relief valve is closed.

[0032] The high-pressure vertical furnace 2 is connected to the pellet lock hopper 1 and the DRI buffer tank 3. The DRI pellets obtained from the reaction in the high-pressure vertical furnace 2 are discharged into the DRI buffer tank 3.

[0033] DRI buffer tank 3 is connected to DRI lock hopper 4 via a discharge valve;

[0034] DRI hopper 4 includes a receiving valve, a discharging valve, a pressurizing port, and a depressurizing valve. The pressurizing port is connected to a second pressurizing device. The second pressurizing device pressurizes the DRI hopper 4. When the air pressure inside the DRI hopper 4 is consistent with that inside the DRI buffer tank 3, pressurization is stopped, the receiving valve is opened, and DRI pellets are received from the DRI buffer tank 3. After receiving, the depressurizing valve is opened to release pressure. When the air pressure inside the DRI hopper 4 is consistent with that of the downstream equipment, pressure release is stopped, and the discharging valve is opened to discharge the DRI pellets.

[0035] This invention matches the feeding requirements (temperature, pressure, flow rate, material characteristics, etc.) of a high-pressure pellet lock hopper, developing a pellet feeding and discharging conveying and control method to meet these requirements. A high-pressure feeding and discharging system suitable for iron ore pellets is developed. By combining process methods, the material properties are maximized, and equipment materials and structures are rationally selected. The pressurization and depressurization rates and operating cycles of the pellet lock hopper 1 are rationally controlled to reduce pellet pulverization and raw material loss caused by pressurization and depressurization. Preferably, different types of level sensors can be installed inside the pellet lock hopper 1 to prevent the feed valve from shutting off due to material carrying. An emergency vent can also be provided at the cone section of the lock hopper to prevent valve jamming caused by inaccurate material levels.

[0036] In this invention, the DRI lock hopper can be pressurized with inert gas. After pressurization, it receives high-temperature DRI from upstream under high-pressure conditions. To prevent room-temperature gas from heating and expanding inside the DRI lock hopper, causing overpressure, the inert gas is preheated to increase its temperature, thus solving the problem of overpressure caused by heat transfer and expansion of the pressurized gas inside the lock hopper due to high-temperature materials. Furthermore, by rationally controlling the pressurization and depressurization rates and times, the loss of DRI powder due to pressurization and depressurization can be reduced.

[0037] In a preferred embodiment, reference Figure 2As shown, the tube wall of the DRI buffer tank 3, from the inside out, includes a wear-resistant lining layer, a refractory material layer, an outer wall layer, a jacket water channel layer, and a jacket outer wall layer. This tube wall structure of the DRI buffer tank 3 meets the unloading requirements of DRI pellets. Utilizing the combination of the jacket water system and refractory material under high temperature and high pressure, heat transfer between the high-temperature pellets and the outer wall of the equipment is achieved through a combination of conductive and radiative heat transfer. Furthermore, the equipment materials, which are resistant to high temperatures, impact, and wear, are rationally selected to meet the harsh operating conditions requiring heat resistance and impact resistance. In other embodiments, the tube wall of the DRI buffer tank 3 can be a tube wall structure found in existing technologies.

[0038] In one embodiment, the high-pressure vertical shaft furnace 2 discharges DRI pellets into the DRI buffer tank 3 via a high-pressure rotary discharge valve 19. The high-pressure rotary discharge valve is a specialized device used in high-pressure, high-dust, or corrosive environments to achieve continuous and stable material discharge. It can discharge material from a high-pressure vessel while maintaining system sealing. Typically, its valve core is driven by a motor or pneumatic actuator, and the blades carry the material from the inlet to the outlet, achieving continuous discharge. In other embodiments, a conventional discharge valve can be used.

[0039] In one embodiment, the high-pressure vertical furnace 2 includes a sampler and a controller. The sampler takes samples online in real time, and the controller adjusts the gas temperature, gas composition, and / or gas flow rate inside the high-pressure vertical furnace 2 based on the sampling results. Since the reaction state inside the high-pressure vertical furnace 2 is related to the temperature, composition, and flow rate of the reducing gas, analysis can be used to adjust the gas temperature, gas composition, and / or gas flow rate inside the high-pressure vertical furnace 2 accordingly, so as to improve the reaction inside the furnace.

[0040] In one embodiment, the high-pressure vertical furnace 2 is sequentially connected to the waste boiler 5 and the reducing gas preheater 6; the reducing gas preheater 6 includes a first channel connected to the reducing gas purification equipment, which outputs the reducing gas treated by the waste boiler 5 to the reducing gas purification equipment; the reducing gas preheater 6 includes a second channel connected to the reducing gas purification equipment, which receives the reducing gas purified by the reducing gas purification equipment, and the purified reducing gas is preheated by the reducing gas in the first channel and then input into the high-pressure vertical furnace 2.

[0041] The reducing gas preheater 6 may include a heating furnace 18 between its second channel and the high-pressure vertical furnace 2. The heating furnace 18 is also connected to the incoming fresh gas, heating the mixed fresh gas and reducing gas. Alternatively, the second channel of the reducing gas preheater 6 can be directly connected to the high-pressure vertical furnace 2, allowing the reducing gas to be directly input into the furnace. The heating furnace can then heat only the incoming fresh gas and input the heated fresh gas into the high-pressure vertical furnace 2, where the fresh gas and reducing gas mix within the furnace.

[0042] This invention addresses the challenges of high-temperature gas cooling methods that often result in wasted sensible heat and low energy efficiency. A furnace top gas heat recovery system is developed, incorporating a combination of a waste boiler and a reducing gas preheater at the furnace top gas outlet to recover heat from the ash-containing furnace top gas. To address the complex flow and heat transfer issues associated with ash particles in the reducing gas preheater, a reasonable flow and temperature field can be created by analyzing the characteristics of the ash and slag, reducing internal dead zones and ash accumulation on the pipe walls, and maximizing the transfer of heat to the clean reducing gas.

[0043] In one embodiment, the waste boiler 5 is a shell-and-tube heat exchanger. The top gas output from the high-pressure vertical furnace 2 flows through the shell side, while the boiler water flows through the tube side. The boiler water is sent out of the boundary area through the steam generated by heat exchange with the top gas.

[0044] The reducing gas purification equipment may include a reducing gas venturi 7, a reducing gas scrubbing tower 8, a reducing gas condenser separator 9, and a decarbonization device connected in sequence. The system also includes a compressor for compressing the purified reducing gas before reduction to the reducing gas preheater 6. The decarbonization device can employ various high-pressure decarbonization methods, including MDEA or low-temperature methanol washing. The circulating gas is first sent to the decarbonization device and then to the compressor, thereby reducing the gas flow rate into the compressor, reducing the compressor outlet head, and significantly reducing overall energy consumption.

[0045] In one embodiment, the bottom of the reducing gas scrubbing tower 8 is connected to a flash tank 12, the bottom of the flash tank 12 is connected to a settling tank 13, and the settling tank 13 is connected to an ash water tank 14 and a separation device 15. The ash water at the bottom of the reducing gas scrubbing tower 8 enters the flash tank 12, the black water after flashing in the flash tank 12 enters the settling tank 13 for gravity settling and solid-liquid separation, the overflow water at the top of the settling tank 13 enters the ash water tank 14, and the slurry at the bottom of the settling tank 13 is pumped to the separation device 15.

[0046] In one embodiment, the pressure-reducing valve of the DRI lock hopper 4 is connected to the lock hopper venturi 16, which is connected to the lock hopper venturi scrubbing tower 17. The vent gas from the DRI lock hopper 4 is a high-temperature, ash-containing gas. After being treated by the lock hopper venturi 16, the ash water wets and cools the particles in the gas before it enters the lock hopper venturi scrubbing tower 17. The clean gas is then vented from the top of the lock hopper venturi scrubbing tower 17. The lock hopper venturi scrubbing tower 17 can be connected to a settling tank 13. The black water at the bottom of the lock hopper venturi scrubbing tower 17 enters the settling tank 13 for gravity settling and solid-liquid separation. The overflow water from the top of the settling tank 13 enters the ash water tank 14, and the slurry at the bottom of the settling tank 13 is pumped to the separation device 15.

[0047] Ash water tank 14 is a buffer tank for the water system of the entire gasification unit. Part of the ash water recovered from ash water tank 14 is pumped to the reducing gas venturi and reducing gas scrubbing tower by a high-pressure pump, and part of the ash water is sent to the on-site wastewater treatment plant as wastewater.

[0048] By adopting the high-pressure gas-based vertical shaft furnace process system provided by this invention, high-pressure feeding of iron ore and high-pressure output of DRI pellets are achieved, ensuring that the entire process of the gas-based vertical shaft furnace, from feeding and in-furnace reaction to discharge, is completed under high pressure. As the furnace pressure increases, the reduction reaction rate accelerates, gas utilization improves, and single-furnace production capacity increases, thereby reducing production costs, saving energy, and improving the overall economic efficiency of the vertical shaft furnace technology. Furthermore, the high-pressure gas-based vertical shaft furnace process has a high gas reduction rate, reducing the total heat and energy requirements of the gas entering the high-pressure furnace, thus lowering the requirements for the reducing gas heating system and saving energy. In addition, the high-pressure gas-based vertical shaft furnace process system provided by this invention decarbonizes the circulating gas before compression, reducing the gas flow rate into the compressor and the compressor outlet head, significantly reducing total energy consumption.

[0049] Example 2

[0050] Embodiment 2 of this utility model provides a high-pressure gas-based vertical furnace process system, referencing... Figure 1 As shown, the system includes the following main equipment: pellet lock hopper 1, high-pressure vertical furnace 2, DRI buffer tank 3, DRI lock hopper 4, waste heat boiler 5, reducing gas preheater 6, reducing gas venturi 7, reducing gas scrubbing tower 8, reducing gas condenser 9, decarbonization device 10, compressor 11, flash tank 12, settling tank 13, ash water tank 14, filtration equipment 15, lock hopper depressurization gas venturi 16, lock hopper depressurization gas scrubbing tower 17, heating furnace 18, and high-pressure rotary discharge valve 19.

[0051] The high-pressure vertical shaft furnace needs to overcome the problems brought about by the coupling of high temperature and high pressure, including the selection of furnace equipment materials, the selection and arrangement of refractory materials, and protecting the outer wall of the equipment from overheating. Under high pressure, the pellet conversion rate is higher. A reasonable hydrogen-to-carbon ratio and operating temperature are used to ensure a high metal conversion rate in the pellets, ensuring that the furnace top section and cooling section do not overheat and that the pellets do not stick. To match the high-pressure vertical shaft furnace, the feeding and unloading systems in the high-pressure gas-based vertical shaft furnace system need to meet the requirements of high-pressure feeding and high-pressure unloading. The system provided in this embodiment adopts an integral forging and multi-layer water-cooled jacket combination, which has higher sealing performance compared to the rotary unloading valve of a low-pressure vertical shaft furnace. In the high-pressure feeding and unloading system, a pioneering three-valve feeding and unloading type is used, overcoming the problem of sealing with material on the ground.

[0052] In the above system, the pellet lock hopper 1 is located at the top of the vertical shaft furnace, and the outlet of the lock hopper is connected to the high-pressure vertical shaft furnace 2. After the pellet lock hopper receives the material and pressurizes it to the pressure of the high-pressure vertical shaft furnace, it releases the pellets into the high-pressure vertical shaft furnace 2.

[0053] Inside the high-pressure vertical furnace 2, the reduced DRI pellets are cooled by fresh gas and then discharged into the lower storage tank through the high-pressure rotary discharge valve 19.

[0054] The key equipment in the high-temperature and high-pressure receiving and unloading system for DRI pellets is the DRI storage tank 3 and the DRI lock hopper 4. The high-pressure rotary discharge valve 19 is connected to the inlet of the DRI storage tank 3 and the outlet is connected to the DRI lock hopper 4. The DRI pellets are fed downstream through the DRI lock hopper 4.

[0055] The key equipment in the furnace top gas heat recovery system is the waste boiler 5 and the reducing gas preheater 6. The furnace top gas outlet of the high-pressure vertical furnace 2 is connected to the inlet of the waste boiler 5, and the outlet is connected to the reducing gas preheater 6. The purified low-temperature circulating gas enters the heating furnace 18 after exchanging heat with the furnace top gas.

[0056] The key equipment in the high-pressure reducing gas heating system is the heating furnace 18. After purification, the circulating gas is compressed by a compressor to the reducing gas preheater 6, and the preheated reducing gas is sent to the heating furnace for heating.

[0057] The high-pressure circulating gas scrubbing system consists of a reducing gas venturi 7, a reducing gas scrubbing tower 8, and a reducing gas condenser separator 9. The reducing gas preheater 6 is connected to the reducing gas venturi 7, the outlet of the reducing gas venturi 7 is connected to the inlet of the reducing gas scrubbing tower 8, and the outlet of the reducing gas scrubbing tower 8 is connected to the inlet of the reducing gas condenser separator 9, and then the gas is sent to the downstream decarbonization unit.

[0058] The DRI lock hopper 4 vent gas scrubbing system connects the DRI lock hopper 4 outlet vent gas to the lock hopper depressurization gas venturi 16, and the lock hopper depressurization gas venturi 16 is connected to the lock hopper depressurization gas scrubbing tower 17.

[0059] The decarbonization device 10 is connected to the reducing gas condenser 9, and the decarbonized gas is sent to the compressor 11 for pressurization.

[0060] The compressor 11 is connected to the decarbonization device at its inlet and to the reducing gas preheater 6 at its outlet to preheat the low-temperature reducing gas.

[0061] The greywater treatment system includes a primary flash tank 12, a settling tank 13, a greywater tank 14, and a filter device 15. Blackwater discharged from the reducing gas scrubbing tower 8 is connected to the flash tank 12. The blackwater from the flash tank 12, after cooling, is connected to the settling tank 13, and the solid-liquid discharge outlet at the bottom of the settling tank 13 is connected to the filter device 15. The clarified water outlet of the settling tank 13 is connected to the greywater tank 14, which serves as a buffer for the greywater system. A portion of the drainage from the greywater tank 14 is pressurized by a pump and connected to the reducing gas venturi 7 and the reducing gas scrubbing tower 8. A portion of the drainage from the greywater tank 14 is cooled and discharged as wastewater. The gas from the flash tank 12, after cooling and condensation, is sent to the flare.

[0062] The following is an illustrative description of the workflow of the high-pressure gas-based vertical furnace process system provided in this embodiment.

[0063] Iron ore pellets are fed into the pellet storage silo via a bucket elevator and discharged into pellet lock hopper 1 via a discharge valve. After receiving one hopper of pellets, pellet lock hopper 1 interlocks and closes the pellet storage silo's baffle valve based on the high material level in the hopper, then seals it off to isolate it from the pellet storage silo. High-pressure inert gas is used to pressurize pellet lock hopper 1, and the pressure is reduced to above the hopper's operating pressure via a regulating valve. When the pressure measurement point of pellet lock hopper 1 matches that of the high-pressure vertical furnace 2, the pellets are discharged into the high-pressure vertical furnace 1 by gravity. After discharge, when the hopper's material level reaches 0, the hopper's discharge valve is closed, and pressure release begins. Pressure release is achieved by releasing gas from the hopper at a certain flow rate via a regulating valve. The released gas can be directly discharged into the air or first filtered in a gas recovery device. When the pressure in pellet lock hopper 1 matches that of the upper storage silo, feeding continues, completing one cycle.

[0064] Iron ore pellets undergo a reduction reaction with heated reducing gas in a high-pressure vertical furnace 2. The gas after the reaction is discharged from the furnace through the furnace top outlet. The reduced DRI pellets pass through the reduction section of the vertical furnace and enter the cooling section. Fresh gas is introduced into the cooling section to cool the DRI pellets. After cooling, the DRI pellets are discharged into the lower DRI storage tank 3 through the high-pressure rotary discharge valve 19.

[0065] The rotational speed of the high-pressure rotary discharge valve 19 is adjusted by the material level in the DRI storage tank 3. High-pressure inert gas is used to pressurize the DRI lock hopper 4, and the pressure is reduced to above the lock hopper's operating pressure via a regulating valve. When the pressure in the DRI lock hopper 4 matches the pressure measuring point in the DRI storage tank 3, the DRI lock hopper 4 begins to collect material, and then begins to depressurize. When the pressure in the DRI lock hopper 4 matches the pressure measuring point in the downstream equipment, the DRI lock hopper 4 begins to discharge material downstream. The vent gas from the DRI lock hopper 4 is high-temperature, ash-containing gas. After passing through the lock hopper vent gas venturi 16, the ash water wets and cools the particles in the gas before it enters the lock hopper vent gas scrubbing tower 17, where clean gas is released into the atmosphere.

[0066] The ash-laden, high-temperature top gas discharged from the top outlet of the vertical shaft furnace first passes through waste boiler 5 to lower its temperature. Waste boiler 5 is a shell-and-tube heat exchanger; the high-temperature top gas flows through the shell side, while the boiler water flows through the tube side. The boiler water generates steam through heat exchange with the high-temperature gas. The generated steam is then separated by steam-water separation in the steam drum and sent out of the boundary area. The gas exiting waste boiler 5 passes through reducing gas preheater 6, where it is preheated by heat exchange through the indirect wall. The recovery of heat from the top gas is key to energy saving in the entire system, thereby reducing the consumption of fuel gas in heating furnace 18. The cooled top gas then enters reducing gas venturi 7. At the venturi throat, the ash water and gas energy are at their maximum, allowing the ash water to wet the solid particles in the gas, laying the foundation for gas-solid separation. The venturi is directly connected to reducing gas scrubbing tower 8. The gas-water mixture flows upward from the tower bottom, coming into cross-flow contact with the ash water entering from the tower tray, removing the remaining solid particles. Then, it is sent to reducing gas condenser separator 9 for cooling before being sent to the decarbonization unit. The reducing gas first enters the gas-liquid separator of the decarbonization unit, and after dehydration, it enters the bottom of the absorption tower. Inside the tower, it flows countercurrently upwards, contacting the decarbonization solvent coming down from the top of the tower, undergoing heat and mass transfer. The CO2 in the gas is absorbed, and the purified gas is drawn out from the top of the tower, which is the decarbonized circulating gas. The decarbonized circulating gas is compressed by a compressor to the reducing gas preheater 6. The preheated reducing gas is mixed with fresh gas and then sent to the heating furnace for heating. The temperature is controlled by adjusting the fuel gas flow rate.

[0067] The ash water at the bottom of the reducing gas scrubbing tower 8 is sent to the flash tank 12 for flash evaporation after depressurization. After condensation and separation, the non-condensable gas is sent to the flare for treatment. The black water at the bottom of the flash tank 12 is discharged to the settling tank 13 for gravity settling and solid-liquid separation. To promote solid settling, a reagent is added to the settling tank 13. The slurry at the bottom of the settling tank 13 is pumped to the separation device 15 for solid-liquid separation. The overflow water from the top of the settling tank 13 flows by gravity into the ash water tank 14. The ash water tank 14 is the buffer tank of the water system of the entire gasification unit. Part of the ash water recovered from the ash water tank 14 is pumped to the reducing gas venturi and reducing gas scrubbing tower by a high-pressure pump, and part of the ash water is sent to the on-site wastewater treatment plant as wastewater.

[0068] By adopting the high-pressure gas-based vertical shaft furnace process system provided by this invention, high-pressure feeding of iron ore and high-pressure output of DRI pellets are achieved, ensuring that the entire process of the gas-based vertical shaft furnace, from feeding and in-furnace reaction to discharge, is completed under high pressure. As the furnace pressure increases, the reduction reaction rate accelerates, gas utilization improves, and single-furnace production capacity increases, thereby reducing production costs, saving energy, and improving the overall economic efficiency of the vertical shaft furnace technology. Furthermore, the high-pressure gas-based vertical shaft furnace process has a high gas reduction rate, reducing the total heat and energy requirements of the gas entering the high-pressure furnace, thus lowering the requirements for the reducing gas heating system and saving energy. In addition, the high-pressure gas-based vertical shaft furnace process system provided by this invention decarbonizes the circulating gas before compression, reducing the gas flow rate into the compressor and the compressor outlet head, significantly reducing total energy consumption.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Those skilled in the art should understand that modifications can be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A high-pressure gas-based vertical shaft furnace process system, characterized in that, include: Pellet lock hopper (1), high-pressure vertical furnace (2), DRI buffer tank (3), and DRI lock hopper (4); among which The pellet lock hopper (1) is located at the top of the vertical furnace and includes a feed valve, a discharge valve, an air inlet, and a pressure relief valve. The air inlet is connected to the first pressurizing device. The pellet lock hopper (1) is used to receive iron ore pellets from the upper storage silo through the feed valve. When the level of the iron ore pellets reaches the threshold, the feed valve is closed. Pressurized gas is received through the air inlet. When the gas pressure in the pellet lock hopper (1) is consistent with the gas pressure in the high-pressure vertical furnace (2), pressurization is stopped. The discharge valve is opened to discharge the iron ore pellets into the high-pressure vertical furnace (2). After the discharge is completed, the discharge valve is closed and the pressure relief valve is opened. When the gas pressure in the pellet lock hopper (1) is consistent with the gas pressure in the upper storage silo, the pressure relief valve is closed. The high-pressure vertical furnace (2) is connected to the pellet lock hopper (1) and the DRI buffer tank (3), and the DRI pellets obtained from the reaction in the high-pressure vertical furnace (2) are discharged into the DRI buffer tank (3); The DRI buffer tank (3) is connected to the DRI lock hopper (4) via a discharge valve; The DRI lock hopper (4) includes a receiving valve, a discharging valve, a pressurizing port, and a depressurizing valve. The pressurizing port is connected to a second pressurizing device. The DRI lock hopper (4) is pressurized by the second pressurizing device. When the air pressure in the DRI lock hopper (4) is consistent with that in the DRI buffer tank (3), the pressurization is stopped, the receiving valve is opened, and the DRI pellets are received from the DRI buffer tank (3). After the material collection is completed, the pressure relief valve is opened to release the pressure. When the air pressure in the DRI lock hopper (4) is consistent with that of the downstream equipment, the pressure relief is stopped, and the discharge valve is opened to discharge the DRI pellets.

2. The high-pressure gas-based vertical shaft furnace process system according to claim 1, characterized in that, The wall of the DRI buffer tank (3) consists of, from the inside out, a wear-resistant lining layer, a refractory material layer, an outer wall layer, a jacket water channel layer, and a jacket outer wall layer.

3. The high-pressure gas-based vertical shaft furnace process system according to claim 1, characterized in that, The high-pressure vertical furnace (2) discharges the DRI pellets into the DRI buffer tank (3) through the high-pressure rotary unloading valve (19).

4. The high-pressure gas-based vertical shaft furnace process system according to claim 1, characterized in that, The high-pressure vertical furnace (2) includes a sampler and a controller. The sampler samples online in real time, and the controller adjusts the gas temperature, gas composition, and / or gas flow rate in the high-pressure vertical furnace (2) according to the sampling results.

5. The high-pressure gas-based vertical shaft furnace process system according to claim 1, characterized in that, The high-pressure vertical furnace (2) is connected in sequence to the waste boiler (5) and the reducing gas preheater (6); the reducing gas preheater (6) includes a first channel, which is connected to the reducing gas purification equipment and outputs the reducing gas processed by the waste boiler (5) to the reducing gas purification equipment; the reducing gas preheater (6) includes a second channel, which is connected to the reducing gas purification equipment and receives the reducing gas purified by the reducing gas purification equipment. The purified reducing gas is preheated by the reducing gas in the first channel and then input into the high-pressure vertical furnace (2).

6. The high-pressure gas-based vertical shaft furnace process system according to claim 5, characterized in that, The second channel of the reducing gas preheater (6) includes a heating furnace (18) between it and the high-pressure vertical furnace (2). The heating furnace (18) is also connected to the incoming fresh gas to heat the mixed fresh gas and the reducing gas.

7. The high-pressure gas-based vertical shaft furnace process system according to claim 5, characterized in that, The waste boiler (5) is a shell-and-tube heat exchanger. The top gas output from the high-pressure vertical furnace (2) flows through the shell side, and the boiler water flows through the tube side. The boiler water is sent out of the boundary area through the steam generated by heat exchange with the top gas.

8. The high-pressure gas-based vertical shaft furnace process system according to claim 5, characterized in that, The reducing gas purification equipment includes a reducing gas venturi (7), a reducing gas scrubbing tower (8), a reducing gas condenser (9), and a decarbonization device connected in sequence; the system also includes a compressor for compressing the reducing gas before reduction after being processed by the reducing gas purification equipment to the reducing gas preheater (6).

9. The high-pressure gas-based vertical shaft furnace process system according to claim 8, characterized in that, The bottom of the reducing gas scrubbing tower (8) is connected to a flash tank (12), the bottom of the flash tank (12) is connected to a settling tank (13), and the settling tank (13) is connected to an ash water tank (14) and a separation device (15). The ash water at the bottom of the reducing gas scrubbing tower (8) enters the flash tank (12), the black water after flashing in the flash tank (12) enters the settling tank (13) for gravity settling and solid-liquid separation, the overflow water at the top of the settling tank (13) enters the ash water tank (14), and the sludge at the bottom of the settling tank (13) is pumped to the separation device (15).

10. The high-pressure gas-based vertical shaft furnace process system according to claim 1, characterized in that, The pressure reduction valve of the DRI lock bucket (4) is connected to the lock bucket depressurization gas venturi (16), and the lock bucket depressurization gas venturi (16) is connected to the lock bucket depressurization gas scrubbing tower (17).

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