System and method for cracking methanol by using tail gas of heating furnace

Abstract

The invention discloses a system and method for cracking methanol by using heating furnace tail gas, the system for cracking methanol by using heating furnace tail gas comprises a gasification cracking furnace and a methanol storage device, the methanol storage device is communicated with the gasification cracking furnace through a liquid inlet pipe, and the gasification cracking furnace is communicated with a gas outlet pipe. The gasification cracking furnace exchanges heat with the tail gas of the heating furnace, methanol entering the gasification cracking furnace through the liquid inlet pipe is cracked to generate cracked gas, and the cracked gas enters the gas outlet pipe. The method has the beneficial effects that cracking gas generated by cracking methanol through tail gas of the heating furnace is used for combustion of the heating furnace, compared with coal gas and natural gas, the fuel cost of the heating furnace is greatly reduced, tail gas waste heat is fully utilized, and energy conservation and environmental protection are achieved.

Description

Technical Field

[0001] The present invention relates to the field of heating furnaces, and in particular to a system and method for cracking methanol by utilizing tail gas from a heating furnace. Background Art

[0002] For heating furnaces that generate heat for metal smelting by burning fuel (such as coal gas, natural gas, etc.), the flue gas emitted by the heating furnace during metal smelting contains a large amount of waste heat, and the flue gas temperature is often several hundred degrees Celsius. It would be a waste if this heat energy is directly discharged.

[0003] Methanol is a liquid industrial fuel. Compared to coal gas and natural gas, methanol has a lower cost, but its calorific value is low and it is difficult to burn fully. Therefore, the industry generally uses coal gas and natural gas as fuel for heating furnaces, and few companies use methanol directly as fuel for heating furnaces. However, methanol can be cracked to form pyrolysis gas, the main components of which are hydrogen and carbon monoxide. Obviously, pyrolysis gas has a higher calorific value. If the waste heat from the flue gas emitted during metal smelting in the heating furnace can be used to crack methanol to produce pyrolysis gas as heating furnace fuel, the combustion cost can be significantly reduced compared to using coal gas and natural gas. Although methanol cracking requires a higher temperature, the presence of a catalyst can significantly reduce the cracking temperature. Summary of the Invention

[0004] The main purpose of the present invention is to provide a system and method for cracking methanol using exhaust gas from a heating furnace, aiming to solve the problems mentioned in the background technology.

[0005] To solve the above problems, the present invention proposes a system for cracking methanol using exhaust gas from a heating furnace, comprising a gasification cracking furnace and a methanol storage device. The methanol storage device is connected to the gasification cracking furnace via a liquid inlet pipe, and the gasification cracking furnace is connected to an outlet pipe. The gasification cracking furnace exchanges heat with the exhaust gas from the heating furnace, cracking the methanol entering the gasification cracking furnace through the liquid inlet pipe to produce cracked gas, which enters the outlet pipe. The gasification and cracking furnace is connected to a smoke exhaust pipe, the exhaust gas of the heating furnace is located in the smoke exhaust pipe, the exhaust pipe is connected to the heating furnace, the exhaust gas inlet end of the gasification and cracking furnace is provided with a second temperature detection device, and the exhaust gas outlet end of the gasification and cracking furnace is provided with a fourth temperature detection device; The outlet end of the air outlet pipe is connected to the burner on the heating furnace, the burner is connected to the outlet end of the air inlet pipe three, and the air inlet end of the air inlet pipe three is connected to a blast device; The burner is connected to the gas outlet end of the second gas inlet pipe, and the gas inlet end of the second gas inlet pipe is connected to a combustible gas storage device.

[0006] In one embodiment, a smoke exhaust valve is provided on the smoke exhaust pipe; The heating furnace is provided with a flame detection device, a temperature detection device 1, and a pressure detection device 1; The gasification and cracking furnace is connected to a dust removal device, and the tail gas from the heating furnace enters the dust removal device after heat exchange with the gasification and cracking furnace.

[0007] In one embodiment, the liquid inlet pipe is provided with a delivery pump, a flow detection device 1, a pressure detection device 2, a shut-off valve 1, and a regulating valve 1.

[0008] In one embodiment, the outlet end of the outlet pipe is connected to a cracked gas storage device, and the cracked gas storage device is provided with a third pressure detection device, a third temperature detection device, and a pressure relief valve; The cracked gas storage device is connected to the burner on the heating furnace through an air inlet pipe 1, and the air inlet pipe 1 is provided with a flow detection device 2, a pressure detection device 4, a shut-off valve 2, and a regulating valve 2.

[0009] In one embodiment, the intake pipe three is provided with a flow detection device four, a pressure detection device six, and a regulating valve four.

[0010] In one embodiment, the second intake pipe is provided with a stop valve, a third flow detection device, a fifth pressure detection device, a third shut-off valve, and a third regulating valve.

[0011] In one embodiment, the outlet end of the outlet pipe is connected to the inlet end of the catalyst filter recovery device, and the outlet end of the catalyst filter recovery device is connected to the cracked gas storage device through a gas pipe; The catalyst filtering and recovery device comprises: The tank body is provided with an air inlet, the air inlet is connected to the air outlet end of the air outlet pipe, the upper end of the tank body is detachably and sealedly mounted with a tank cover, the top of the tank cover is connected to the air supply pipe, the bottom of the tank body is provided with a drain pipe, and the drain pipe is mounted with a control valve; The filter screen is located inside the tank body and is sealed with the inner wall of the tank body. The filter screen divides the internal space of the tank body into two parts, an upper part and an lower part. The air inlet is connected to the lower part of the tank body. The cracked gas located in the lower part of the tank body can only reach the upper part of the tank body by passing through the filter screen.

[0012] In one embodiment, an exhaust pipe is provided above the filter screen. The cracked gas passing through the filter screen flows from bottom to top and enters the exhaust pipe from the lower end. A swing hose is connected to the outer wall of the exhaust pipe. One end of the swing hose is connected to the interior of the exhaust pipe. A striking block is installed at the other end of the swing hose. The striking block is provided with a second exhaust hole. The cracked gas in the exhaust pipe enters the swing hose and is discharged from the second exhaust hole, driving the other end of the swing hose to swing up and down to strike the filter screen. The swing hose is made of stainless steel foil.

[0013] In one embodiment, an exhaust hole 1 is provided at the upper end of the exhaust pipe.

[0014] In addition, the present application also proposes a method for cracking methanol using exhaust gas from a heating furnace, wherein any of the aforementioned systems for cracking methanol using exhaust gas from a heating furnace is used to perform the following steps: The blast device is started, the combustible gas storage device is opened, and air and the combustible gas stored in the combustible gas storage device are injected into the burner for combustion to heat the heating furnace and form the exhaust gas of the heating furnace; The tail gas from the heating furnace is sent to the gasification and cracking furnace for heat exchange with the gasification and cracking furnace; The methanol is fed into the gasification cracking furnace, where it is heated and cracked to form cracked gas; The cracking gas is injected into the burner and mixed with air for combustion to heat the heating furnace and form the heating furnace tail gas; Close the combustible gas storage device and stop injecting combustible gas into the burner. Build a closed-loop, self-sustaining system in which the waste heat from the heating furnace exhaust gas is used to crack methanol into cracked gas for use by the burner. The cracked gas is then burned to form the heating furnace exhaust gas, which is then used to crack methanol. Among them, the heating furnace tail gas and methanol meet the following requirements: ; ; ; ; , where is the instantaneous heat required for methanol cracking at an instantaneous flow rate of A. It is the instantaneous waste heat of the heating furnace tail gas required for methanol cracking. is the instantaneous flow rate of the heating furnace exhaust gas, is the instantaneous flow rate of air entering the burner, is the instantaneous flow rate of oxygen in the air entering the burner, is the specific heat of the heating furnace exhaust gas, and It is the temperature of the tail gas from the heating furnace before and after heat exchange with the gasification and cracking furnace. It is the heat exchange efficiency between the heating furnace tail gas and the gasification cracking furnace.

[0015] Beneficial effects: 1. The technical solution of this application realizes the use of the tail gas of the heating furnace to crack methanol to produce cracking gas for combustion in the heating furnace. Compared with coal gas and natural gas, it greatly reduces the fuel cost of the heating furnace, fully utilizes the waste heat of the tail gas, and is energy-saving and environmentally friendly. 2. By optimizing system parameters, the cracked gas produced by methanol can meet the needs of the heating furnace for combustion and metal smelting, eliminating the need for additional raw fuels such as coal gas and natural gas, thereby minimizing the fuel cost of the heating furnace. At the same time, the waste heat from the exhaust gas generated by the heating furnace can completely crack the methanol, ensuring the closed-loop self-sustaining operation of the system. 3. By installing a catalyst filtration and recovery device in the system to recycle the liquid catalyst in methanol, the consumption of catalyst is reduced and the cost of methanol cracking is lowered; 4. Filter the cracking gas through the filter screen to remove the liquid catalyst. The alternating changes in the air pressure in the long swing hose are used to achieve the end of the swing hose connected to the striking block to swing up and down to strike the filter screen, shaking off the catalyst droplets gathered on the filter screen to prevent the droplets from clogging the filter holes and affecting the filtration efficiency, ensuring that the filter screen maintains high-efficiency filtration for a long time. At the same time, the swing hose is made of stainless steel foil, also known as hand-torn steel, which is soft, thin, high-temperature resistant, and can be bent repeatedly; 5. Energy is obtained from the cracking airflow to achieve a swing hose connected to one end of the striking block to swing up and down to strike the filter screen, which fully utilizes the energy contained in the cracking airflow, has a low striking cost, and does not require an additional set of mechanisms with power sources to strike the filter screen, thus avoiding increased failures caused by an overly complex structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 This is a schematic diagram of a system for cracking methanol using tail gas from a heating furnace according to the present invention; Figure 2 It is a structural schematic diagram of the catalyst filtration and recovery device of the present invention; Figure 3 This is a diagram of the internal structure of the catalyst filtration and recovery device of the present invention; Figure 4 yes Figure 3 Enlarged view of part C in ; Figure 5 It is a schematic structural diagram of the filter screen of the present invention; Figure 6 The present invention is a schematic diagram of the exhaust pipe, swing hose position in the filter screen; Figure 7 yes Figure 6 A magnified view of part A in FIG; Figure 8This is a schematic diagram of the structure of the swing hose of the present invention Figure 1 ; Figure 9 yes Figure 8 A magnified view of part B in FIG; Figure 10 This is a schematic diagram of the structure of the swing hose of the present invention Figure 2 .

[0018] The following are the descriptions of the reference numerals: 1. Heating furnace; 2. Flame detection device; 3. Temperature detection device 1; 4. Pressure detection device 1; 5. Smoke exhaust pipe; 6. Smoke exhaust valve; 7. Temperature detection device 2; 8. Gasification and cracking furnace; 9. Dust removal device; 10. Methanol storage device; 11. Delivery pump; 12. Flow detection device 1; 13. Pressure detection device 2; 14. Shut-off valve 1; 15. Regulating valve 1; 16. Liquid inlet pipe; 17. Gas outlet pipe 18. Catalyst filtration and recovery device; 181. Tank body; 182. Support legs; 183. Drain pipe; 184. Control valve; 185. Inclined surface; 186. Tank cover; 187. Stopper; 188. Mounting ring 1; 189. Pressing ring; 1810. Filter screen; 1811. Swinging track; 1812. Exhaust pipe; 1813. Exhaust hole 1; 1814. Mounting ring 2; 1815. Connecting rod; 1816. Mounting pipe; 1817. Swinging hose; 1818. Strike block; 1819. Exhaust hole 2; 1820. Gas hood; 1821. Air inlet; 19. Gas pipeline; 20. Cracking gas storage device; 21. Pressure detection device three; 22. Temperature detection device three; 23. Inlet pipe one; 24. Flow detection device two; 25. Pressure detection device four; 26. Shut-off valve two; 27. Regulating valve two; 28. Burner; 29. Inlet pipe two; 30. Combustible gas storage device; 31. Shut-off valve; 32. Flow detection device three; 33. Pressure detection device five; 34. Shut-off valve three; 35. Regulating valve three; 36. Inlet pipe three; 37. Flow detection device four; 38. Blowing device; 39. Pressure detection device six; 40. Regulating valve four; 41. Pressure relief valve; 42. Temperature detection device four. DETAILED DESCRIPTION

[0019] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0020] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.

[0021] In the present invention, unless otherwise specified or limited, the terms "connection" and "fixation" should be understood in a broad sense. For example, "fixation" can mean fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will be able to understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0022] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the meaning of "and / or" appearing throughout the text includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme in which A and B are satisfied at the same time. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0023] The present invention provides a system for cracking methanol using exhaust gas from a heating furnace. This system utilizes exhaust gas from a heating furnace to crack methanol, generating cracked gas for combustion in a heating furnace (1). Compared to coal gas and natural gas, this significantly reduces the fuel cost of the heating furnace (1), fully utilizes the waste heat from the exhaust gas, and is energy-efficient and environmentally friendly. Adding a certain proportion of liquid catalyst to methanol can significantly lower its cracking temperature, facilitating full utilization of the waste heat from the exhaust gas. Of course, if the exhaust gas temperature is relatively high, the addition of a catalyst to the methanol is also acceptable.

[0024] Furthermore, by optimizing the system parameters, the cracking gas produced by methanol can meet the needs of the heating furnace 1 for burning and smelting metals, without the need for additional raw fuels such as coal gas and natural gas, thereby minimizing the fuel cost of the heating furnace 1. At the same time, the waste heat from the tail gas generated by the heating furnace 1 can completely crack the methanol, ensuring the closed-loop self-sustaining operation of the system.

[0025] Furthermore, by providing a catalyst filtering and recovery device 18 in the system, the liquid catalyst in the methanol can be recovered for secondary use, thereby reducing the consumption of the catalyst and lowering the cost of methanol cracking.

[0026] In addition, the cracking gas is filtered through the filter screen 1810 to remove the liquid catalyst, and the alternating changes in the air pressure in the long swinging hose 1817 are used to enable the end of the swinging hose 1817 connected to the striking block 1818 to swing back and forth up and down to strike the filter screen 1810, so as to shake off the catalyst droplets gathered on the filter screen 1810, and prevent the droplets from clogging the filter holes and affecting the filtration efficiency, thereby ensuring that the filter screen 1810 maintains high-efficiency filtration for a long time. At the same time, the swinging hose 1817 is made of stainless steel foil, that is, hand-torn steel, which is soft, light, and high-temperature resistant. It can be bent repeatedly and obtains energy from the cracking airflow to enable the end of the swinging hose 1817 connected to the striking block 1818 to swing back and forth up and down to strike the filter screen 1810, thereby making full use of the cracking airflow and having a low striking cost. There is no need to set up an additional mechanism with a power source to strike the filter screen 1810, thereby avoiding an increase in failures caused by an overly complex structure.

[0027] Specifically, in one embodiment of the invention, Figure 1 As shown, the system for cracking methanol using exhaust gas from a heating furnace includes a gasification cracking furnace 8 and a methanol storage device 10. The methanol storage device 10 is used to store the methanol to be cracked, and the methanol is mixed with a liquid catalyst, such as [BMIM][HSO4] or [HSO3-BMIM][HSO4], with a liquid catalyst content of 5-10% (mass fraction).

[0028] Specifically, the gasification cracking furnace 8 is essentially a heat exchanger, which exchanges heat with the tail gas from the heating furnace and then acts on methanol to crack the methanol.

[0029] In this embodiment, if Figure 1 As shown, the methanol storage device 10 is connected to the gasification cracking furnace 8 through the liquid inlet pipe 16, and the methanol in the methanol storage device 10 enters the gasification cracking furnace 8 through the liquid inlet pipe 16. Figure 1 As shown, the gasification and cracking furnace 8 is connected to an outlet pipe 17, through which cracked gas is discharged from the gasification and cracking furnace 8. The gasification and cracking furnace 8 exchanges heat with the exhaust gas from the heating furnace, increasing the temperature of the gasification and cracking furnace 8. The methanol entering the gasification and cracking furnace 8 through the liquid inlet pipe 16 is then heated, causing it to crack under the action of the liquid catalyst to produce cracked gas (hydrogen and carbon monoxide). The cracked gas in the gasification and cracking furnace 8 is then discharged from the outlet pipe 17.

[0030] Specifically, such as Figure 1As shown, the gasification cracking furnace 8 is connected to the exhaust pipe 5, the exhaust gas of the heating furnace is located in the exhaust pipe 5, the exhaust pipe 5 is connected to the heating furnace 1, and the exhaust gas generated by the heating furnace 1 enters the gasification cracking furnace 8 through the exhaust pipe 5 and exchanges heat with the gasification cracking furnace 8; Figure 1 As shown, the heating furnace tail gas inlet end of the gasification and cracking furnace 8 is provided with a temperature detection device 2 7, and the heating furnace tail gas discharge end of the gasification and cracking furnace 8 is provided with a temperature detection device 4 42. The temperature detection device 2 7 and the temperature detection device 4 42 are used to detect the temperature of the heating furnace tail gas before and after heat exchange with the gasification and cracking furnace 8.

[0031] In this embodiment, the outlet end of the outlet pipe 17 is connected to the burner 28 on the heating furnace 1, and the cracking gas in the outlet pipe 17 enters the burner 28. The burner 28 is connected to the outlet end of the inlet pipe three 36. The inlet end of the inlet pipe three 36 is connected to a blower 38. The outside air is sent into the inlet pipe three 36 through the blower 38. The air enters the burner 28 through the inlet pipe three 36 and is mixed with the cracking gas to burn to heat the heating furnace 1 and generate heating furnace exhaust.

[0032] In addition, if Figure 1 As shown, the burner 28 is also connected to the outlet end of the second inlet pipe 29, and the inlet end of the second inlet pipe 29 is connected to a combustible gas storage device 30. The combustible gas storage device 30 stores combustible gases such as coal gas and natural gas. In the initial stage of operation of the heating furnace 1, methanol cannot be cracked yet. Therefore, the combustible gas storage device 30 is required to supply combustible gas to the burner 28 for mixing with air for combustion to heat the heating furnace 1 and generate heating furnace tail gas. The heating furnace tail gas is used to preheat the gasification cracking furnace 8. After the temperature of the gasification cracking furnace 8 reaches the methanol cracking temperature, the gasification cracking furnace 8 is supplied with the gasification cracking furnace 8. Methanol is injected into the chemical cracking furnace 8 for cracking to produce cracking gas. The cracking gas enters the burner 28 to replace the combustible gas and mixes with air for combustion, thereby generating heating furnace tail gas. Afterwards, while maintaining the normal operation of the system, the supply of combustible gas is gradually reduced until the supply of combustible gas is completely stopped, so that the cracking gas produced by methanol can meet the needs of the heating furnace 1 for burning and smelting metals, without the need for additional supplementation of raw fuels such as coal gas and natural gas. At the same time, the flue gas generated by the heating furnace 1 can completely crack the methanol, thereby realizing closed-loop self-sustaining operation of the system and minimizing the fuel cost of the heating furnace 1.

[0033] Furthermore, in this embodiment, Figure 1 As shown, the exhaust pipe 5 is provided with an exhaust valve 6, which is used to adjust the instantaneous flow of the exhaust gas from the heating furnace. Figure 1As shown, the heating furnace 1 is provided with a flame detection device 2, a temperature detection device 3, and a pressure detection device 4. The flame detection device 2 is used to detect the combustion condition of the burner 28 in the heating furnace 1 to prevent explosion. The temperature detection device 3 is used to detect the temperature in the heating furnace 1. The pressure detection device 4 is used to detect the pressure in the heating furnace 1 to ensure the normal operation of the heating furnace 1 and the burner 28.

[0034] Furthermore, in this embodiment, Figure 1 As shown, the gasification and cracking furnace 8 is connected to a dust removal device 9. The exhaust gas from the heating furnace exchanges heat with the gasification and cracking furnace 8 and enters the dust removal device 9 for dust removal. The exhaust gas from the heating furnace after dust removal is discharged into the atmosphere.

[0035] Furthermore, in this embodiment, Figure 1 As shown, the liquid inlet pipe 16 is provided with a delivery pump 11, a flow detection device 12, a pressure detection device 13, a shut-off valve 14, and a regulating valve 15. The delivery pump 11 is used to pump methanol into the gasification cracking furnace 8, the flow detection device 12 is used to detect the methanol flow in the liquid inlet pipe 16, the pressure detection device 13 is used to detect the methanol delivery pressure in the liquid inlet pipe 16, the shut-off valve 14 is used to control the on-off of the liquid inlet pipe 16, and the regulating valve 15 is used to adjust the instantaneous flow of methanol in the liquid inlet pipe 16.

[0036] Furthermore, in this embodiment, Figure 1 As shown, the outlet end of the outlet pipe 17 is connected to a cracked gas storage device 20, which temporarily stores the cracked gas in the cracked gas storage device 20 to prevent pressure fluctuations from affecting the combustion effect of the burner 28. In addition, the methanol cracking efficiency does not reach 100%, and is generally around 95%. Therefore, in order to ensure that the pressure of the cracked gas sent to the burner 28 is stable and without fluctuations, it is usually necessary to produce more cracked gas, and then use the cracked gas storage device 20 to store this excess cracked gas to provide a guarantee for subsequent adjustment of the instantaneous flow rate of the cracked gas sent to the burner 28; the cracked gas storage device 20 is provided with a pressure detection device 3 21, a temperature detection device 3 22, and a pressure relief valve 41. The pressure detection device 3 21 is used to detect the air pressure in the cracked gas storage device 20, the temperature detection device 3 22 is used to detect the temperature in the cracked gas storage device 20, and the pressure relief valve 41 is used to relieve the high pressure in the cracked gas storage device 20 to protect the safety of the cracked gas storage device 20.

[0037] Furthermore, in this embodiment, Figure 1As shown, the cracked gas storage device 20 is connected to the burner 28 on the heating furnace 1 through the air inlet pipe 1 23. The air inlet pipe 1 23 is provided with a flow detection device 2 24, a pressure detection device 4 25, a shut-off valve 26, and a regulating valve 27. The flow detection device 24 is used to detect the flow of the cracked gas sent to the burner 28 in the air inlet pipe 1 23, the pressure detection device 4 25 is used to detect the air pressure in the air inlet pipe 1 23, the shut-off valve 26 is used to control the opening and closing of the air inlet pipe 1 23, and the regulating valve 27 is used to adjust the instantaneous flow of the cracked gas sent to the burner 28 in the air inlet pipe 1 23.

[0038] Furthermore, in this embodiment, Figure 1 As shown, the intake pipe three 36 is provided with a flow detection device four 37, a pressure detection device six 39, and a regulating valve four 40. The flow detection device four 37 is used to detect the air flow in the intake pipe three 36, the pressure detection device six 39 is used to detect the air pressure in the intake pipe three 36, and the regulating valve four 40 is used to adjust the air flow in the intake pipe three 36.

[0039] Furthermore, in this embodiment, Figure 1 As shown, the intake pipe 2 29 is provided with a stop valve 31, a flow detection device 3 32, a pressure detection device 5 33, a shut-off valve 34, and a regulating valve 35. The stop valve 31 is used to prevent the combustible gas from flowing back. The flow detection device 3 32 is used to detect the flow of the combustible gas in the intake pipe 2 29. The pressure detection device 5 33 is used to detect the pressure of the combustible gas in the intake pipe 2 29. The shut-off valve 34 is used to control the on-off of the intake pipe 2 29. The regulating valve 35 is used to adjust the flow of the combustible gas in the intake pipe 2 29.

[0040] Furthermore, in this embodiment, Figure 1 As shown, the outlet end of the outlet pipe 17 is connected to the air inlet end of the catalyst filtering and recovery device 18, and the outlet end of the catalyst filtering and recovery device 18 is connected to the cracked gas storage device 20 through the gas transmission pipe 19. In this design, the cracked gas discharged from the gasification and cracking furnace 8 is first filtered by the catalyst filtering and recovery device 18 and then sent to the cracked gas storage device 20. The liquid catalyst in the cracked gas is recovered by the catalyst filtering and recovery device 18 for secondary use, thereby reducing the consumption of the catalyst and reducing the cost of methanol cracking.

[0041] Specifically, such as Figure 2-Figure 9 As shown, the catalyst filtering and recovery device 18 includes a tank body 181 and a filter mesh 1810. The filter mesh 1810 is made of twisted metal wire or non-metal wire and is used to filter liquid and liquid foam in the gas. In this embodiment, the filter mesh 1810 can filter out liquid (liquid droplet diameter 3-50μm) in high-temperature gas (for example, about 400°C).

[0042] In this embodiment, if Figure 2 and Figure 3 As shown, the tank body 181 is provided with an air inlet 1821, and the air inlet 1821 is connected to the air outlet end of the air outlet pipe 17. The upper end of the tank body 181 is detachably and sealedly installed with a tank cover 186, and the top of the tank cover 186 is connected to the air supply pipe 19. The bottom of the tank body 181 is provided with support legs 182 and a drain pipe 183. The drain pipe 183 is installed with a control valve 184. When the control valve 184 is opened, the liquid catalyst gathered at the bottom of the tank body 181 is discharged from the drain pipe 183. Figure 3 As shown, the inner bottom surface of the tank body 181 is a slope 185 . This design facilitates the liquid catalyst to gather at the bottom of the tank body 181 .

[0043] In this embodiment, if Figure 3 As shown, the filter mesh 1810 is located inside the tank body 181, and the filter mesh 1810 is sealed and connected to the inner wall of the tank body 181. The filter mesh 1810 divides the internal space of the tank body 181 into two parts, an upper part and an lower part. The air inlet 1821 is connected to the lower part of the space inside the tank body 181. The cracked gas in the lower part of the space inside the tank body 181 can only pass through the filter mesh 1810 to reach the upper part of the space inside the tank body 181. Therefore, the cracked gas can be filtered through the filter mesh 1810 to remove the liquid catalyst.

[0044] In this embodiment, if Figure 3 、 Figure 6 、 Figure 8 、 Figure 10 As shown, an exhaust pipe 1812 is provided above the filter screen 1810, and the cracking gas passing through the filter screen 1810 flows from bottom to top and enters the exhaust pipe 1812 from the lower end thereof. The outer wall of the exhaust pipe 1812 is connected to a swing hose 1817, and the swing hose 1817 is made of stainless steel foil, that is, hand-torn steel, which is soft, thin, high-temperature resistant, and can be bent repeatedly.

[0045] In this embodiment, if Figure 3 、 Figure 6 、 Figure 8 、 Figure 10As shown, one end of the swing hose 1817 is connected to the inside of the exhaust cylinder 1812 through the mounting tube 1816. The mounting tube 1816 is hard in texture. One end of the mounting tube 1816 is fixedly connected to the hard exhaust cylinder 1812, and the other end is detachably plugged and sealed to the swing hose 1817. Preferably, the mounting tube 1816 and the exhaust cylinder 1812 are integrally formed. The other end of the swing hose 1817 is detachably and fixedly installed with a striking block 1818. The striking block 1818 is hard in texture and can knock on the filter screen 1810, causing the filter screen 1810 to vibrate.

[0046] In this embodiment, if Figure 9 As shown, the striking block 1818 is provided with a second exhaust hole 1819. The cracked gas entering the exhaust cylinder 1812 passes through the swing hose 1817 and is discharged from the second exhaust hole 1819. Since the swing hose 1817 is soft and thin, when the air pressure in the swing hose 1817 is low, the striking block 1818 drives the other end of the swing hose 1817 to fall, causing the end of the swing hose 1817 connected to the mounting tube 1816 to bend. After the swing hose 1817 is bent, the cracked gas does not flow smoothly in the swing hose 1817. As the cracked gas continuously enters, The air pressure in the swing hose 1817 increases, causing the bent swing hose 1817 to gradually return to its original shape, that is, the swing hose 1817 drives the striking block 1818 and the other end of the swing hose 1817 to rise, and then the cracking gas smoothly passes through the swing hose 1817 and is discharged from the second exhaust hole 1819. After the cracking gas is discharged from the second exhaust hole 1819, the air pressure in the swing hose 1817 drops, causing the swing hose 1817 to bend again, and this cycle repeats, so that the other end of the swing hose 1817 swings up and down to hit the filter screen 1810. The swing trajectory 1811 is shown as Figure 3 As shown by the middle dotted line, the swinging principle of the swinging hose 1817 is similar to the inflatable dancing dolls used for welcoming guests or promotions on the market. The other end of the swinging hose 1817 swings up and down to hit the filter screen 1810, shaking off the catalyst droplets gathered on the filter screen 1810, preventing the droplets from clogging the filter pores and affecting the filtration efficiency, ensuring that the filter screen 1810 maintains high-efficiency filtration for a long time.

[0047] It can be seen that the catalyst filtering and recovery device 18 of this embodiment filters the cracking gas through the filter screen 1810 to filter out the liquid catalyst, and uses the alternating changes in the air pressure in the long swinging hose 1817 to realize the swinging hose 1817 connected to the striking block 1818 to swing back and forth up and down to strike the filter screen 1810, so as to shake off the catalyst droplets gathered on the filter screen 1810, thereby preventing the droplets from clogging the filter holes and affecting the filtering efficiency, and ensuring that the filter screen 1810 maintains high-efficiency filtration for a long time. At the same time, the swinging hose 1817 is made of stainless steel foil, that is, hand-torn steel, which is soft, light, and high-temperature resistant. It can be bent repeatedly, especially obtaining energy from the cracking gas flow to realize the swinging hose 1817 connected to the striking block 1818. One end of the striking block 1818 swings back and forth up and down to strike the filter screen 1810, fully utilizing the energy contained in the cracking gas flow, with low striking cost, and no additional mechanism with a power source for striking the filter screen 1810 is required, thereby avoiding the problems of increased failures and high striking cost caused by overly complex structure.

[0048] Preferably, the cross-section of the swing hose 1817 is flat, such as an oval or a long rectangle. The advantage of this design is that the swing hose 1817 is easier to bend without affecting the gas transmission capacity of the swing hose 1817, and the swing sensitivity is higher, which is conducive to fully hitting the filter screen 1810 and keeping the filter screen 1810 filtering the cracking gas efficiently for a long time.

[0049] Preferably, Figure 8 and Figure 10 As shown, there are multiple swing hoses 1817, and they are symmetrically distributed around the exhaust pipe 1812. This design can fully hit the filter screen 1810 without omission, avoiding droplets clogging the filter holes and affecting the filtration efficiency, ensuring that the filter screen 1810 maintains high-efficiency filtration for a long time. Accordingly, the filter screen 1810 is preferably designed to be an open cup, such as Figure 5 As shown, the impact on the filter screen 1810 is more comprehensive, and the up and down swing of the swing hose 1817 can be fully utilized, such as Figure 6 As shown, the other end of the swing hose 1817 can swing upward or downward to hit the filter screen 1810, and the swing trajectory 1811 is as shown in FIG. Figure 3 As shown by the dotted line, this design has a better striking effect, and the open cup-shaped filter screen 1810 has a larger filtering area and higher filtering capacity than the flat filter screen 1810. Figure 5 The filter screen 1810 is shown with Figure 8 The plurality of swing hoses 1817 shown form Figure 6 The wire mesh demister shown has the advantages of high filtration efficiency, strong filtration capacity and large filtration area.

[0050] Further, such as Figure 3 、 Figure 8 and Figure 10 As shown, the lower end of the exhaust cylinder 1812 is connected to a gas gathering hood 1820, which gathers more cracking gas through the gas gathering hood 1820 to increase the gas volume in the exhaust cylinder 1812, ensuring that when there are many swing hoses 1817, there is enough gas volume to drive all the swing hoses 1817 to swing up and down, and at the same time, the exhaust cylinder 1812 is placed more stably on the filter screen 1810.

[0051] Of course, in order to facilitate the disassembly and replacement of the filter screen 1810 and ensure the sealing of the connection between the filter screen 1810 and the inner wall of the tank body 181, and to avoid the air flow speed being too fast to cause the filter screen 1810 to shake and drive the exhaust pipe 1812 to shake, affecting the swing hose 1817 to drive the striking block 1818 to hit the filter screen 1810, as shown Figure 3-Figure 6 As shown, a plurality of blocks 187 are fixedly installed on the inner wall of the tank body 181, and a mounting ring 188 is placed on the block 187. The outer circumference of the mounting ring 188 is sealed tightly against the inner wall of the tank body 181, and the upper open outer edge of the filter screen 1810 is bonded to the lower surface of the mounting ring 188. The outer wall of the exhaust pipe 1812 is tightly sleeved with a mounting ring 2 1814, and the mounting ring 2 1814 and the mounting ring 188 are coaxially fixedly connected through a connecting rod 1815. A clamping ring 189 is screwed on the inner wall of the tank body 181, and the lower end surface of the clamping ring 189 is tightly against the mounting ring 188. The clamping ring 189 cooperates with the block 187 to clamp and fix the mounting ring 188 to prevent the exhaust pipe 1812 from shaking and ensure the stability of the exhaust pipe 1812 and the gas collection hood 1820.

[0052] In this embodiment, if Figure 6 and Figure 7 As shown, the upper end of the exhaust cylinder 1812 is provided with a plurality of exhaust holes 1813, and the exhaust holes 1813 are used to open and close as needed to adjust the frequency of the up and down swinging of the swinging hose 1817. For example, when the amount of air in the exhaust cylinder 1812 is large, the swinging hose 1817 swings up and down faster. At this time, a plurality of exhaust holes 1813 can be opened to adjust the amount of air entering the swinging hose 1817, thereby reducing the frequency of the up and down swinging of the swinging hose 1817 so that the frequency of the up and down swinging of the swinging hose 1817 meets the demand. The exhaust holes 1813 can be sealed by means of sealing plugs, and the number of exhaust holes 1813 to be opened can be selected as needed.

[0053] In addition, the present application also proposes a method for cracking methanol using exhaust gas from a heating furnace, wherein any of the aforementioned systems for cracking methanol using exhaust gas from a heating furnace is used to perform the following steps: S1, start the blast device 38, open the combustible gas storage device 30, inject air and the combustible gas stored in the combustible gas storage device 30 into the burner 28 for combustion to heat the heating furnace 1 and form the heating furnace exhaust; S2, sending the tail gas from the heating furnace into the gasification and cracking furnace 8 to perform heat exchange with the gasification and cracking furnace 8; S3, after the temperature of the gasification cracking furnace 8 is raised to a temperature suitable for cracking methanol, methanol is fed into the gasification cracking furnace 8, where the methanol is heated and cracked to form cracked gas; S4, injecting the cracked gas into the burner 28 and mixing it with air for combustion to heat the heating furnace 1 and form the heating furnace tail gas; S5. After a period of time, the methanol cracking rate and the cracked gas combustion rate remain dynamically stable. The combustible gas storage device 30 is closed, and the injection of combustible gas into the burner 28 is stopped. The system is then operated in a closed loop and self-sustaining manner, in which methanol is cracked by the residual heat of the heating furnace tail gas to form cracked gas for use by the burner 28, and the cracked gas is burned to form heating furnace tail gas to completely crack the methanol. Among them, the heating furnace tail gas and methanol meet the following requirements: ; ; ; ; , where is the instantaneous heat required for methanol cracking at an instantaneous flow rate of A. It is the instantaneous waste heat of the heating furnace tail gas required for methanol cracking. is the instantaneous flow rate of the heating furnace exhaust gas, is the instantaneous flow rate of air entering the burner, is the instantaneous flow rate of oxygen in the air entering the burner, is the specific heat of the heating furnace exhaust gas, and It is the temperature of the tail gas from the heating furnace before and after heat exchange with the gasification and cracking furnace. It is the heat exchange efficiency between the exhaust gas of the heating furnace and the gasification cracking furnace. When the exhaust gas flow, waste heat and methanol supply of the heating furnace meet the above conditions, a closed-loop self-sustaining operation of the system can be constructed in which the waste heat of the exhaust gas of the heating furnace is used to crack methanol to form cracking gas for use by the burner, and the cracking gas is burned to form the exhaust gas of the heating furnace to completely crack the methanol. There is no need to additionally supplement the original fuel such as coal gas and natural gas, thereby minimizing the fuel cost of the heating furnace.

[0054] The following is a detailed description of a method for cracking methanol using heating furnace tail gas according to the present application using a specific embodiment.

[0055] 1. Assuming the instantaneous flow rate of methanol is A = 1t / h, the methanol cracking stage occurs: CH3OH→CO+2H2(ΔH=+90kJ / mol), so the instantaneous heat required for the complete cracking of methanol with an instantaneous flow rate of A is =1000kg / h 32g / mol×90kJ / mol=2812500kJ / h≈781kWh; 2. Based on the instantaneous methanol flow rate A=1t / h, the gasification cracking furnace volume can be designed to be 10 m³, and the material is 316L stainless steel + ceramic lining to make it resistant to corrosion by acidic ionic liquids (i.e. liquid catalysts such as [BMIM][HSO4] or [HSO3-BMIM][HSO4]). The heat exchange area in the gasification cracking furnace is designed to be 200 m², and plate heat exchangers are preferably used; 3. The instantaneous flow rate of methanol is A=1t / h. For the convenience of calculation, it is assumed that the instantaneous flow rate of methanol cracking gas is also 1t / h. All the methanol cracking gas is used for combustion in the burner. In fact, the methanol cracking efficiency cannot reach 100%, generally around 95%. In addition, in order to ensure that the pressure of the cracking gas sent to the burner is stable and has no fluctuations, it is usually necessary to produce more cracking gas, that is, the instantaneous flow rate of methanol is slightly greater than 1t / h. Slightly more than 781kWh, and then the excess cracked gas is stored in a cracked gas storage device; 4. The combustion reaction in the burner is: 2H2+O2→2H2O 2CO+O2→2CO2 Burner air requirement (taking excess air coefficient α=1.2 as an example): H2 requires O2: 125 kg / h ÷ 2 g / mol ÷ 2 = 31250 mol / h CO requires O2: 875 kg / h ÷ 28 g / mol ÷ 2 = 15625 mol / h Total O2 demand: 31250 mol / h + 15625 mol / h = 46875 mol / h; Corresponding instantaneous air flow rate = 46875 ÷ 0.21 ≈ 223214 mol / h ≈ 6467 kg / h; Actual instantaneous air flow = 6467X1.2 = 7760 kg / h; 5. Instantaneous flow rate of exhaust gas generated by heating furnace = 7760 kg / h + 1t / h = 8760 kg / h; 6. Instantaneous waste heat of heating furnace tail gas required for methanol cracking = × ×( − )× , Take 1.1, Take 0.8, Take 150℃ (the cracking temperature of methanol drops to 150-200℃ after adding liquid catalyst), and get =8760 kg / h×1.1×( −150)×0.8≥ =2812500kJ / h, we get ≥515℃, the temperature difference of the heating furnace tail gas before and after passing through the cracking furnace is ≥365℃. It can be seen that when the instantaneous flow rate of methanol A=1t / h, the condition for stable closed-loop self-sustaining operation of the system is; the temperature difference of the heating furnace tail gas before and after passing through the cracking furnace is ≥365℃, the instantaneous flow rate of air entering the burner =6467X1.2=7760 kg / h, and the instantaneous flow rate of the heating furnace tail gas flowing through the gasification cracking furnace is 8760 kg / h.

[0056] 7. The heat released after the cracking gas and air in the heating furnace are mixed and fully burned: Q 燃烧 =125kg / h×120MJ / kg+875kg / h×10MJ / kg=23750MJ / h≈6597kWh; Heat required for methanol cracking It is 781kWh, 781 6597=11.8%, the heating furnace thermal efficiency is calculated as 60%, 23750MJ / h-2812500kJ / h=20.9GJ / h, 20.9GJ / hX60%=12.54GJ / h is used for steelmaking. Assuming that each ton of scrap steel requires 500 kWh, the amount of scrap steel that can be smelted is 12.54GJ / h 3.6MJ / kWh 500kWh / t=7t / h; 8. According to the heat release of 6597kWh after the cracking gas and air are fully burned in the heating furnace and the scrap steel loading capacity of 7t / h, the power of the heating furnace can be designed to be 15 MW and the furnace size can be Φ3m×6m.

[0057] In this embodiment, the heat exchange area in the gasification and cracking furnace can also be designed to other areas, but it is necessary to ensure that the methanol stays in the gasification and cracking furnace for a long enough time to ensure that the methanol is fully and thoroughly cracked.

[0058] In this embodiment, the capacity of the cracked gas storage device can be designed to be 5 t, which can buffer the cracked gas production for 5 hours and the pressure is 0.5 MPa, thereby maintaining stable delivery of the cracked gas to the burner.

[0059] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention description and drawings under the inventive concept of the present invention, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A system for cracking methanol using tail gas from a heating furnace, characterized in that: It includes a gasification cracking furnace and a methanol storage device, wherein the methanol storage device is connected to the gasification cracking furnace through a liquid inlet pipe, and the gasification cracking furnace is connected to an outlet pipe. The gasification cracking furnace exchanges heat with the tail gas of the heating furnace, cracks the methanol entering the gasification cracking furnace through the liquid inlet pipe to produce cracked gas, and the cracked gas enters the outlet pipe; The gasification and cracking furnace is connected to a smoke exhaust pipe, the exhaust gas of the heating furnace is located in the smoke exhaust pipe, the exhaust pipe is connected to the heating furnace, the exhaust gas inlet end of the gasification and cracking furnace is provided with a second temperature detection device, and the exhaust gas outlet end of the gasification and cracking furnace is provided with a fourth temperature detection device; The outlet end of the air outlet pipe is connected to the burner on the heating furnace, the burner is connected to the outlet end of the air inlet pipe three, and the air inlet end of the air inlet pipe three is connected to a blast device; The burner is connected to the gas outlet end of the second gas inlet pipe, and the gas inlet end of the second gas inlet pipe is connected to a combustible gas storage device.

2. The system for cracking methanol using exhaust gas from a heating furnace according to claim 1, wherein: The smoke exhaust pipe is provided with a smoke exhaust valve; The heating furnace is provided with a flame detection device, a temperature detection device 1, and a pressure detection device 1; The gasification and cracking furnace is connected to a dust removal device, and the tail gas from the heating furnace enters the dust removal device after heat exchange with the gasification and cracking furnace.

3. The system for cracking methanol using exhaust gas from a heating furnace according to claim 1, wherein: The liquid inlet pipe is provided with a delivery pump, a flow detection device 1, a pressure detection device 2, a cut-off valve 1, and a regulating valve 1.

4. The system for cracking methanol using exhaust gas from a heating furnace according to claim 1, wherein: The outlet end of the gas outlet pipe is connected to a cracked gas storage device, and the cracked gas storage device is provided with a third pressure detection device, a third temperature detection device, and a pressure relief valve; The cracked gas storage device is connected to the burner on the heating furnace through an air inlet pipe 1, and the air inlet pipe 1 is provided with a flow detection device 2, a pressure detection device 4, a shut-off valve 2, and a regulating valve 2.

5. The system for cracking methanol using exhaust gas from a heating furnace as claimed in claim 4, characterized in that: The air intake pipe three is provided with a flow detection device four, a pressure detection device six, and a regulating valve four.

6. The system for cracking methanol using exhaust gas from a heating furnace as claimed in claim 4, characterized in that: The second air inlet pipe is provided with a stop valve, a third flow detection device, a fifth pressure detection device, a third shut-off valve, and a third regulating valve.

7. The system for cracking methanol using exhaust gas from a heating furnace as claimed in claim 4, characterized in that: The outlet end of the outlet pipe is connected to the inlet end of the catalyst filter recovery device, and the outlet end of the catalyst filter recovery device is connected to the cracked gas storage device through the gas pipe; The catalyst filtering and recovery device comprises: The tank body is provided with an air inlet, the air inlet is connected to the air outlet end of the air outlet pipe, the upper end of the tank body is detachably and sealedly mounted with a tank cover, the top of the tank cover is connected to the air supply pipe, the bottom of the tank body is provided with a drain pipe, and the drain pipe is mounted with a control valve; The filter screen is located inside the tank body and is sealed with the inner wall of the tank body. The filter screen divides the internal space of the tank body into two parts, an upper part and an lower part. The air inlet is connected to the lower part of the tank body. The cracked gas located in the lower part of the tank body can only reach the upper part of the tank body by passing through the filter screen.

8. The system for cracking methanol using exhaust gas from a heating furnace as claimed in claim 7, characterized in that: An exhaust pipe is provided above the filter screen. The cracked gas passing through the filter screen flows from bottom to top and enters the exhaust pipe from the lower end. A swing hose is connected to the outer wall of the exhaust pipe. One end of the swing hose is connected to the interior of the exhaust pipe. A striking block is installed at the other end of the swing hose. A second exhaust hole is provided on the striking block. The cracked gas in the exhaust pipe enters the swing hose and is discharged from the second exhaust hole, driving the other end of the swing hose to swing up and down to hit the filter screen. The swing hose is made of stainless steel foil.

9. The system for cracking methanol using exhaust gas from a heating furnace according to claim 8, characterized in that: An exhaust hole 1 is provided at the upper end of the exhaust cylinder.

10. A method for cracking methanol using tail gas from a heating furnace, characterized in that: The system for cracking methanol using heating furnace tail gas according to any one of claims 1 to 9 is used to perform the following steps: The blast device is started, the combustible gas storage device is opened, and air and the combustible gas stored in the combustible gas storage device are injected into the burner for combustion to heat the heating furnace and form the exhaust gas of the heating furnace; The tail gas from the heating furnace is sent to the gasification and cracking furnace for heat exchange with the gasification and cracking furnace; The methanol is fed into the gasification cracking furnace, where it is heated and cracked to form cracked gas; The cracking gas is injected into the burner and mixed with air for combustion to heat the heating furnace and form the heating furnace tail gas; Close the combustible gas storage device and stop injecting combustible gas into the burner. Build a closed-loop, self-sustaining system in which the waste heat from the heating furnace exhaust gas is used to crack methanol into cracked gas for use by the burner. The cracked gas is then burned to form the heating furnace exhaust gas, which is then used to crack methanol. Among them, the heating furnace tail gas and methanol meet the following requirements: ； ； ； ； , where is the instantaneous heat required for methanol cracking at an instantaneous flow rate of A. It is the instantaneous waste heat of the heating furnace tail gas required for methanol cracking. is the instantaneous flow rate of the heating furnace exhaust gas, is the instantaneous flow rate of air entering the burner, is the instantaneous flow rate of oxygen in the air entering the burner, is the specific heat of the heating furnace exhaust gas, and It is the temperature of the tail gas from the heating furnace before and after heat exchange with the gasification and cracking furnace. It is the heat exchange efficiency between the heating furnace tail gas and the gasification cracking furnace.

Images