Waste heat recovery transformation process for tail section of converter outlet flue

Abstract

The invention discloses a waste heat recovery transformation process for the tail section of a converter outlet flue, which comprises the following steps: 1, a waste heat recovery inlet section flue tee joint is arranged, and two ports of the waste heat recovery inlet section flue tee joint in the horizontal direction are respectively a first port and a second port; the first port is connected with an outlet of a tail section flue of a converter outlet flue in a sealed mode, the second port is blocked, and a connecting section of the waste heat recovery inlet section flue tee joint is connected with an inlet of a top evaporator of an evaporative cooler in a sealed mode; secondly, a tail-section flue waste heat recovery system is additionally arranged, and thirdly, after the tail-section flue waste heat recovery system is installed, an inlet of the waste heat recovery system is communicated with a second port of the waste heat recovery inlet section flue tee joint in a sealed mode; and the connecting section is separated from the top inlet of the evaporative cooler, and a gas output pipe of the evaporative cooler is closed. The method has the advantages that original equipment and converter production are not affected in the transformation process, switching is fast after transformation is completed, waste heat of high-temperature coal gas is fully recycled, and heat energy waste is avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of converter waste heat recovery, in particular to a waste heat recovery modification process for the last section of the converter outlet flue. BACKGROUND

[0002] The LT method is a dry method of purifying and recovering converter gas. The heat and oxidized iron dust in the gas, high-temperature flue gas and dust generated during the converter steelmaking process are recovered, purified and removed by the LT method. The LT method converter waste heat recovery and purification system includes a waste heat recovery system and a purification system, wherein the waste heat recovery system is directly linked to the production process of the converter steelmaking and directly participates in the production as part of the steelmaking process.

[0003] The flue gas outlet of the converter is connected with the converter outlet flue, and the last section of the converter outlet flue is the last section flue. The LT method is usually used for processing the last section flue. The current LT method processing mode is that a spray gun is arranged in the last section flue of the converter outlet flue for spraying and cooling the high-temperature flue gas, the outlet of the last section flue is connected with an evaporative cooler, and the evaporative cooler is provided with a spray hole for arranging the spray gun. The bottom of the evaporative cooler is provided with an evaporative cooler gas output pipe connected with a gas discharge pipe. The high-temperature gas generated by the converter has a temperature of about 1450℃, and is cooled by the converter outlet flue. The temperature of the gas in the last section flue is still about 900℃. The LT method is used to process the high-temperature gas at 900℃, that is, the temperature of the flue gas is rapidly reduced from about 900℃ to about 200℃ by spraying water mist in the last section flue and the evaporative cooler, and the gas at about 200℃ is outputted to the outside through the evaporative cooler gas output pipe and the gas discharge pipe for further dust removal. The above LT method processing mode results in complete waste of the waste heat resource at 900-200℃, and produces mud and sewage to pollute the environment. SUMMARY

[0004] The present application needs to solve the technical problem of providing a waste heat recovery modification process for the last section of the converter outlet flue, which does not affect the original LT method processing equipment and the converter production during the modification process, and can fully recover and utilize the waste heat of the high-temperature gas in the last section of the outlet flue after the modification is completed, thereby avoiding the waste of heat energy and reducing the cost of converter steelmaking.

[0005] To solve the above problems, the technical scheme adopted by the present application is as follows: a waste heat recovery modification process for the last section of the converter outlet flue, comprising the following steps: first, a waste heat recovery inlet section flue tee is arranged, the waste heat recovery inlet section flue tee includes a flue body arranged horizontally, a connecting section is arranged at the bottom of the flue body, and the two ends of the flue body in the horizontal direction are respectively a first port and a second port; the first port is sealingly connected with the outlet of the last section flue of the converter outlet flue, the second port is plugged, and the connecting section is sealingly connected with the top evaporator inlet of the evaporative cooler; Before the modification is completed, the high-temperature coal gas generated by the converter is led to the end section flue of the converter outlet flue, and after being sprayed and cooled in the end section flue, the high-temperature coal gas is led to the spray cooling evaporative cooler through the waste heat recovery inlet section flue three-way pipe and the connecting section; the heat energy of the high-temperature coal gas is recovered by the original waste heat recovery system of the converter outlet flue, and the high-temperature coal gas is treated by the LT method; II. An end section flue waste heat recovery system is additionally provided, and the end section flue waste heat recovery system comprises a waste heat recovery system inlet, a waste heat recovery system outlet, a waste heat drum, and a waste heat recovery mechanism; the installation of the end section flue waste heat recovery system does not affect the normal operation of the converter, the converter outlet flue, and the original waste heat recovery system of the converter outlet flue; III. After the installation of the end section flue waste heat recovery system is completed, the waste heat recovery system inlet is in sealed communication with the second port of the waste heat recovery inlet section flue three-way pipe; the connecting section is disconnected from the top inlet of the evaporative cooler, and the evaporative cooler coal gas output pipe at the bottom of the evaporative cooler is closed; after the modification is completed, the high-temperature coal gas generated by the converter is not sprayed after being led to the end section flue of the converter outlet flue, but is treated and cooled by the full dry method in the waste heat recovery mechanism through the second port of the waste heat recovery inlet section flue three-way pipe, the waste heat recovery system inlet, and the waste heat recovery system outlet.

[0006] Further, the foregoing waste heat recovery modification process for the end section of the converter outlet flue, wherein the waste heat recovery inlet section flue three-way pipe adopts a water-cooled vaporization structure, the left and right ends of the flue body are respectively provided with a flue body upper header and a flue body lower header, and the upper and lower ends of the connecting section are respectively provided with a connecting section upper header and a connecting section lower header; the flue body upper header and the connecting section upper header are in communication with the first drum in the original waste heat recovery system of the converter outlet flue through the inlet section flue riser pipe; the flue body lower header is connected with a flue body lower header water inlet pipe provided with a first control valve, and the connecting section lower header is connected with a connecting section lower header water inlet pipe provided with a second control valve; the flue body lower header water inlet pipe and the connecting section lower header water inlet pipe are both in communication with the inlet section flue downcomer pipe, and the inlet section flue downcomer pipe is in communication with the first drum in the original waste heat recovery system of the converter outlet flue.

[0007] Further, the foregoing waste heat recovery modification process for the end section of the converter outlet flue, wherein in the second port of the first step, a water-cooled cover plate is used for plugging; after the installation of the end section flue waste heat recovery system is completed, the water-cooled cover plate is removed to enable the waste heat recovery system inlet to be in sealed communication with the second port of the waste heat recovery inlet section flue three-way pipe; a heat preservation cover plate is used to disconnect the connecting section from the top inlet of the evaporative cooler, and the evaporative cooler coal gas output pipe at the bottom of the evaporative cooler is closed by the evaporative cooler coal gas output control valve.

[0008] Further, the aforementioned waste heat recovery transformation process for the last section of the converter outlet flue, wherein the waste heat recovery mechanism comprises: a cooling flue, the inlet of the cooling flue is the inlet of the waste heat recovery system, the outlet end of the cooling flue is provided with an adiabatic transition flue tee joint, the adiabatic transition flue tee joint has three flue ports, one of which is in communication with the outlet end of the cooling flue, and the other two are in communication with the first and second gas-solid coupling separators respectively, the top of the first gas-solid coupling separator is connected with the flue gas inlet end of the vertically arranged first quenching fire tube heat exchanger through a first connecting flue; the top of the second gas-solid coupling separator is connected with the flue gas inlet end of the vertically arranged second quenching fire tube heat exchanger through a second connecting flue; the lower end of the first quenching fire tube heat exchanger is connected with a first flue gas output pipe and a first ash discharge pipe, and the lower end of the second quenching fire tube heat exchanger is connected with a second flue gas output pipe and a second ash discharge pipe; the cooling flue, the first connecting flue and the second connecting flue all adopt water-cooled wall vaporization flue structure; the outer wall of the first gas-solid coupling separator is provided with a first separator heat exchange pipe cooling mechanism, and the outer wall of the second gas-solid coupling separator is provided with a second separator heat exchange pipe cooling mechanism; the cooling flue, the first connecting flue, the second connecting flue, the cylinder of the first quenching fire tube heat exchanger, the cylinder of the second quenching fire tube heat exchanger, the first separator heat exchange pipe cooling mechanism and the second separator heat exchange pipe cooling mechanism are all in communication with the waste heat drum through a plurality of riser pipes and a plurality of downcomer pipes.

[0009] Further, the aforementioned waste heat recovery transformation process for the last section of the converter outlet flue, wherein the cooling flue comprises a cooling flue section and a cooling flue section two which are sequentially connected in the flue gas flow direction, the inlet of the cooling flue section is the inlet of the waste heat recovery system, the inlet of the cooling flue section is used for sealing connection with the second port of the waste heat recovery inlet section flue tee joint, and the outlet of the cooling flue section two is connected with the adiabatic transition flue tee joint; the cooling flue section and the cooling flue section two are respectively provided with a cooling flue upper header and a cooling flue lower header, the cooling flue upper header is in communication with the waste heat drum through a riser pipe, and the cooling flue lower header is in communication with the waste heat drum through a downcomer pipe.

[0010] Further, the aforementioned waste heat recovery transformation process for the last section of the converter outlet flue, wherein the first connecting flue comprises a first connecting flue section one and a first connecting flue section two connected in sequence along the direction of flue gas flow, the lower end of the first connecting flue section one is connected with the first separator flue gas outlet at the top of the first gas-solid coupling separator, the first connecting flue section one is upwardly bent to transition and connect with the upper end of the first connecting flue section two, the first connecting flue section two is downwardly bent, and the lower end of the first connecting flue section two is connected with the first flue gas inlet of the first quenching fire tube heat exchanger; the two ends of the first connecting flue section one are respectively provided with a first connecting flue section one upper header and a first connecting flue section one lower header, and the two ends of the first connecting flue section two are respectively provided with a first connecting flue section two upper header and a first connecting flue section two lower header; the first connecting flue section one upper header and the first connecting flue section two upper header are respectively connected with the waste heat drum through riser pipes, and the first connecting flue section one lower header and the first connecting flue section two lower header are respectively connected with the waste heat drum through downcomer pipes. The second connecting flue comprises a second connecting flue section one and a second connecting flue section two connected in sequence along the direction of flue gas flow, the lower end of the second connecting flue section one is connected with the second separator flue gas outlet at the top of the second gas-solid coupling separator, the second connecting flue section one is upwardly bent to transition and connect with the upper end of the second connecting flue section two, the second connecting flue section two is downwardly bent, and the lower end of the second connecting flue section two is connected with the second flue gas inlet of the second quenching fire tube heat exchanger; the two ends of the second connecting flue section one are respectively provided with a second connecting flue section one upper header and a second connecting flue section one lower header, and the two ends of the second connecting flue section two are respectively provided with a second connecting flue section two upper header and a second connecting flue section two lower header; the second connecting flue section one upper header and the second connecting flue section two upper header are respectively connected with the waste heat drum through riser pipes, and the second connecting flue section one lower header and the second connecting flue section two lower header are respectively connected with the waste heat drum through downcomer pipes.

[0011] Further, the aforementioned waste heat recovery transformation process for the last section of the converter outlet flue, wherein the first gas-solid coupling separator is provided with a first dust collecting hopper at the bottom, the bottom of the first dust collecting hopper is connected with the first dust cooling device through a first dust collecting hopper output pipe, and the first dust cooling device is connected with the first dust bin; the second gas-solid coupling separator is provided with a second dust collecting hopper at the bottom, the bottom of the second dust collecting hopper is connected with the second dust cooling device through a second dust collecting hopper output pipe, and the second dust cooling device is connected with the second dust bin.

[0012] Further, the aforementioned waste heat recovery modification process for the last section of the converter outlet flue, wherein the first gas-solid coupling separator comprises a first body section cylindrical body and a first conical section body, the first separator heat exchange pipe cooling mechanism comprises: a first heat exchange coil assembly and a first straight section heat exchange pipe assembly, the first heat exchange coil assembly comprises first heat exchange coils wound on the outer wall of the first conical section body, the first straight section heat exchange pipe assembly comprises a plurality of first straight section heat exchange pipes arranged at intervals around the outer wall of the first body section cylindrical body, the upper ends of all the first straight section heat exchange pipes are in communication with the first straight section heat exchange upper header, the lower ends of all the first straight section heat exchange pipes are in communication with the first straight section heat exchange lower header, the first straight section heat exchange upper header and the first straight section heat exchange lower header are arranged around the upper and lower ends of the outer wall of the first body section cylindrical body; the inlet end of the first heat exchange coil in the first heat exchange coil assembly is in communication with the waste heat drum through a downcomer, the outlet end of the first heat exchange coil in the first heat exchange coil assembly is in communication with the waste heat drum through an upcomer; the first straight section heat exchange upper header is in communication with the waste heat drum through an upcomer, the first straight section heat exchange lower header is in communication with the waste heat drum through a downcomer; the second gas-solid coupling separator comprises a second body section cylindrical body and a second conical section body, the second separator heat exchange pipe cooling mechanism comprises: a second heat exchange coil assembly and a second straight section heat exchange pipe assembly, the second heat exchange coil assembly comprises second heat exchange coils wound on the outer wall of the second conical section body, the second straight section heat exchange pipe assembly comprises a plurality of second straight section heat exchange pipes arranged at intervals around the outer wall of the second body section cylindrical body, the upper ends of all the second straight section heat exchange pipes are in communication with the second straight section heat exchange upper header, the lower ends of all the second straight section heat exchange pipes are in communication with the second straight section heat exchange lower header, the second straight section heat exchange upper header and the second straight section heat exchange lower header are arranged around the upper and lower ends of the outer wall of the second body section cylindrical body; the inlet end of the second heat exchange coil in the second heat exchange coil assembly is in communication with the waste heat drum through a downcomer, the outlet end of the second heat exchange coil in the second heat exchange coil assembly is in communication with the waste heat drum through an upcomer; the second straight section heat exchange upper header is in communication with the waste heat drum through an upcomer, the second straight section heat exchange lower header is in communication with the waste heat drum through a downcomer.

[0013] Further, the aforementioned waste heat recovery modification process for the last section of the converter outlet flue, wherein the first smoke gas output pipe and the second smoke gas output pipe are both connected to a smoke gas output main pipe; the smoke gas output main pipe; the outlet of the smoke gas output main pipe is the outlet of the waste heat recovery system; The output end of the evaporative cooler gas output pipe at the bottom of the evaporative cooler is provided with a tee joint, a evaporative cooler gas output control valve is arranged on the evaporative cooler gas output pipe, one end of the tee joint is connected to the gas discharge pipe, and the other end of the tee joint is used to be connected to the smoke gas output main pipe; In the third step, when the tail flue waste heat recovery system is installed, the evaporative cooler gas output pipe at the bottom of the evaporative cooler is closed through the evaporative cooler gas output control valve, and the flue gas output main pipe is connected with the three-way connector, so that the waste heat recovery system outlet of the added tail flue waste heat recovery system is connected with the flue gas discharge pipe of the original converter outlet flue waste heat recovery system.

[0014] Further, the converter outlet flue tail section waste heat recovery reconstruction process has the advantages that the first dust discharge pipe and the second dust discharge pipe are connected with the heat exchanger dust discharge main pipe; and the heat exchanger dust discharge main pipe.

[0015] The converter outlet flue tail section waste heat recovery reconstruction process provided by the application has the advantages that the added tail flue waste heat recovery system is outside the original converter outlet flue waste heat recovery system, and the construction, installation and debugging of the tail flue waste heat recovery system do not affect the normal work of the converter, the converter outlet flue and the original converter outlet flue waste heat recovery system. After the tail flue waste heat recovery system is installed, only the waste heat recovery system inlet is sealed and connected with the second port of the tail flue three-way connector, the connecting section is separated from the evaporative cooler inlet, and the evaporative cooler gas output pipe is closed, so that the new tail flue waste heat recovery system can be operated, the switching time of the new system is very short, and the switching is very convenient. The new tail flue waste heat recovery system replaces the traditional LT method and realizes full dry method treatment, can effectively recover the heat energy of the high-temperature flue gas at 900 DEG C in the tail flue, avoids heat energy loss and reduces the steelmaking cost, avoids the pollution of the environment caused by a large amount of sludge due to the LT method treatment, and effectively improves the enthalpy value of the coal gas product, thereby improving the quality of the coal gas product. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 FIG. 1 is a structural schematic diagram of a tail flue waste heat recovery system added in a converter outlet flue tail section waste heat recovery reconstruction process according to the application.

[0017] Figure 2 FIG. 2 is a schematic diagram of the arrangement structure of a waste heat drum and its rising pipe and falling pipe in the tail flue waste heat recovery system added in the converter outlet flue tail section waste heat recovery reconstruction process according to the application.

[0018] Figure 3 FIG. 3 is a schematic diagram of the pipeline connection principle structure between the waste heat inlet section flue three-way connector and the first drum in the original converter outlet flue waste heat recovery system. DETAILED DESCRIPTION

[0019] The application will be further described in detail below with reference to the drawings and preferred embodiments.

[0020] As shown in Figure 1 , Figure 2 indicated, a waste heat recovery modification process for the last section of the converter outlet flue, I. First, set the waste heat recovery inlet section flue tee 1, the waste heat recovery inlet section flue tee 1 includes a horizontally arranged flue body 11, the bottom of the flue body 11 is provided with a connecting section 12, the two ends of the flue body 11 in the horizontal direction are respectively a first port 13 and a second port 14; the first port 13 is sealingly connected with the outlet of the last flue 2 of the converter outlet flue 200, the second port 14 is plugged, and the connecting section 12 is sealingly connected with the evaporator cooler inlet 3001 at the top of the evaporative cooler 300. In this embodiment, the second port 14 is plugged with a water-cooled cover plate 141.

[0021] Before the modification is completed, the high-temperature gas generated by the converter passes through the converter outlet flue 200 to the last flue 2, and the high-temperature gas is sprayed and cooled in the last flue 2, then enters the evaporative cooler 300 through the waste heat recovery inlet section flue tee 1 and the connecting section 12 for spraying and cooling. The heat energy of the high-temperature gas is recovered by the original converter outlet flue waste heat recovery system, and the high-temperature gas is treated by the LT method.

[0022] II. Add a last flue waste heat recovery system, which includes a waste heat recovery system inlet 310, a waste heat recovery system outlet, a waste heat drum 9, and a waste heat recovery mechanism. The last flue waste heat recovery system does not affect the normal operation of the converter, the converter outlet flue 200, and the original converter outlet flue waste heat recovery system during installation.

[0023] III. After the installation of the last flue waste heat recovery system is completed, the waste heat recovery system inlet 310 is sealingly communicated with the second port 14 of the waste heat recovery inlet section flue tee 1, specifically, the water-cooled cover plate 141 is removed so that the waste heat recovery system inlet is sealingly communicated with the second port 14 of the waste heat recovery inlet section flue tee 1. The connecting section 12 is separated from the evaporator cooler inlet 3001, and the evaporative cooler gas output pipe 3002 at the bottom of the evaporative cooler 300 is closed. Specifically, in this embodiment, the connecting section 12 and the evaporator cooler inlet 3001 are separated by a heat preservation cover plate 3003. The evaporative cooler gas output pipe 3002 at the bottom of the evaporative cooler 300 is closed by the evaporative cooler gas output control valve 3004.

[0024] After the modification is completed, the high-temperature gas generated by the converter enters the last flue 2 through the converter outlet flue 200 and is not sprayed, but is treated and cooled by the full dry method in the waste heat recovery mechanism through the second port 14 of the waste heat recovery inlet section flue tee 1, the waste heat recovery system inlet 310, and then discharged from the waste heat recovery system outlet. As shown in Figure 3As shown, in the embodiment, the waste heat recovery inlet section flue tee 1 adopts a water-cooled vaporization structure, the left and right ends of the flue body 11 are respectively provided with a flue body upper header 111 and a flue body lower header 112, and the upper and lower ends of the connecting section 12 are respectively provided with a connecting section upper header 121 and a connecting section lower header 122. The flue body upper header 111 and the connecting section upper header 121 are connected in communication with the first drum 100 in the original converter outlet flue waste heat recovery system through the inlet section flue riser 101. The flue body lower header 112 is connected with a flue body lower header water inlet pipe 1121, and the connecting section lower header 122 is connected with a connecting section lower header water inlet pipe 1221 with a first control valve 1222. The flue body lower header water inlet pipe 1121 and the connecting section lower header water inlet pipe 1222 are both connected in communication with the inlet section flue downcomer 102, and the inlet section flue downcomer 102 is connected in communication with the first drum 100 in the original converter outlet flue waste heat recovery system.

[0025] As shown in Figure 1 , Figure 2 As shown in the embodiment, the waste heat recovery mechanism includes: a cooling flue 3, the cooling flue inlet is a waste heat recovery system inlet 310, one end of the waste heat recovery inlet section flue tee 1 is communicated with the outlet of the last section flue 2 of the converter outlet flue, the other end of the waste heat recovery inlet section flue tee 1 is connected with the cooling flue 3, and the outlet end of the cooling flue 3 is provided with an adiabatic transition flue tee 4. The adiabatic transition flue tee 4 has three flue ports, one of which is communicated with the outlet end of the cooling flue 3, and the other two are respectively communicated with a first gas-solid coupling separator 5 and a second gas-solid coupling separator 6.

[0026] The top of the first gas-solid coupling separator 5 is connected with the flue gas inlet end of a vertically arranged first quenching fire tube heat exchanger 7 through a first connecting flue. The top of the second gas-solid coupling separator 6 is connected with the flue gas inlet end of a vertically arranged second quenching fire tube heat exchanger 8 through a second connecting flue. The lower end of the first quenching fire tube heat exchanger 7 is connected with a first flue gas output pipe 71 and a first ash discharge pipe 72. The lower end of the second quenching fire tube heat exchanger 8 is connected with a second flue gas output pipe 81 and a second ash discharge pipe 82. The cooling flue 3, the first connecting flue and the second connecting flue all adopt a water-cooled wall vaporization flue structure. The first flue gas output pipe 71 and the second flue gas output pipe 81 are both connected to a flue gas output main pipe 10. The first ash discharge pipe 72 and the second ash discharge pipe 82 are both connected with a heat exchanger dust discharge main pipe 20. The outlet of the flue gas output main pipe 10 is the waste heat recovery system outlet 101.

[0027] The above-mentioned adiabatic transition flue tee 4 plays a role of transition and adiabatic, and the high-temperature coal gas in the cooling flue 3 is divided into two streams through the adiabatic transition flue tee 4 and then enters the first gas-solid coupling separator 5, the first quenching fire tube heat exchanger 7, and the second gas-solid coupling separator 6, the second quenching fire tube heat exchanger 8, respectively, so that the heat recovery of the high-temperature coal gas generated in the converter is shared by two sets of equipment, which can effectively reduce the weight of the quenching fire tube heat exchanger and the gas-solid coupling separator, and can ensure that the heat energy of the high-temperature coal gas is fully released.

[0028] The output end of the evaporative cooler gas output pipe 3002 at the bottom of the evaporative cooler 300 in the original converter outlet flue waste heat recovery system is provided with a tee connector 50, the evaporative cooler gas output pipe 300 is provided with an evaporative cooler gas output control valve 3004, one end of the tee connector 50 is connected with the gas discharge pipe 40, and the other end of the tee connector 50 is used to be connected with the flue gas output main pipe 10. When the final-stage flue waste heat recovery system is installed, the evaporative cooler gas output pipe 3002 at the bottom of the evaporative cooler 300 is closed through the evaporative cooler gas output control valve 3004, and at the same time, the flue gas output main pipe 10 is connected with the tee connector 50, so that the waste heat recovery system outlet 101 of the added final-stage flue waste heat recovery system is connected with the gas discharge pipe 40 of the original converter outlet flue waste heat recovery system.

[0029] The outer wall of the first gas-solid coupling separator 5 is provided with a first separator heat exchange pipe cooling mechanism, and the outer wall of the second gas-solid coupling separator 6 is provided with a second separator heat exchange pipe cooling mechanism. The cooling flue 3, the first and second connecting flues, the cylinder of the first quenching fire tube heat exchanger 7, the cylinder of the second quenching fire tube heat exchanger 8, the first separator heat exchange pipe cooling mechanism, and the second separator heat exchange pipe cooling mechanism are respectively connected with the waste heat drum 9 through the ascending pipes and the descending pipes.

[0030] The cooling flue 3 includes a first cooling flue section 31 and a second cooling flue section 32 which are sequentially connected along the flue gas flow direction, the inlet of the first cooling flue section 31 is connected with the waste heat inlet section flue 1, and the outlet of the second cooling flue section 32 is connected with one flue port of the adiabatic transition flue tee 4. The two ends of the first cooling flue section 31 are provided with a first cooling flue section upper header 311 and a first cooling flue section lower header 312, and the two ends of the second cooling flue section 32 are provided with a second cooling flue section upper header 321 and a second cooling flue section lower header 322. The first cooling flue section upper header 311 is connected with the waste heat drum 9 through a first ascending pipe 3111, the second cooling flue section upper header 321 is connected with the waste heat drum 9 through a second ascending pipe 3211, and the waste heat drum 9 is provided with a first descending pipe 91 which is connected with the first cooling flue section lower header 312 and the second cooling flue section lower header 322 through two water supply pipes, respectively.

[0031] In this embodiment, the first connecting flue comprises a first connecting flue section 51 and a first connecting flue section 52 connected in sequence along the direction of flue gas flow, the lower end of the first connecting flue section 51 is connected with the first separator flue gas outlet 501 at the top of the first gas-solid coupling separator 5, the first connecting flue section 51 is bent upward to transition and connect with the upper end of the first connecting flue section 52, the first connecting flue section 52 is bent downward, and the lower end of the first connecting flue section 52 is connected with the first flue gas inlet 701 of the first quenching fire tube heat exchanger 7. The two ends of the first connecting flue section 51 are respectively provided with a first connecting flue section upper header 511 and a first connecting flue section lower header 512, and the two ends of the first connecting flue section 52 are respectively provided with a first connecting flue section upper header 521 and a first connecting flue section lower header 522. The first connecting flue section upper header 511 and the first connecting flue section lower header 512 are respectively connected with the waste heat drum 9 through a third rising pipe 5111 and a fourth rising pipe 5121; the first connecting flue section lower header 512 and the first connecting flue section lower header 522 are connected with the waste heat drum 9 through a second falling pipe 92.

[0032] The second connecting flue comprises a second connecting flue section 61 and a second connecting flue section 62 connected in sequence along the direction of flue gas flow, the lower end of the second connecting flue section 61 is connected with the second separator flue gas outlet 601 at the top of the second gas-solid coupling separator 6, the second connecting flue section 61 is bent upward to transition and connect with the upper end of the second connecting flue section 62, the second connecting flue section 62 is bent downward, and the lower end of the second connecting flue section 62 is connected with the second flue gas inlet 801 of the second quenching fire tube heat exchanger 8. The two ends of the second connecting flue section 61 are respectively provided with a second connecting flue section upper header 611 and a second connecting flue section lower header 612, and the two ends of the second connecting flue section 62 are respectively provided with a second connecting flue section upper header 621 and a second connecting flue section lower header 622. The second connecting flue section upper header 611 and the second connecting flue section lower header 612 are respectively connected with the waste heat drum 9 through a fifth rising pipe 6111 and a sixth rising pipe 6211; the second connecting flue section lower header 612 and the second connecting flue section lower header 622 are connected with the waste heat drum 9 through a third falling pipe 93.

[0033] The first gas-solid coupling separator 5 comprises a first body segment columnar cylinder 53 and a first conical segment cylinder 54, and the first separator heat exchange pipe cooling mechanism comprises a first heat exchange coil assembly and a first straight segment heat exchange pipe assembly. The first heat exchange coil assembly comprises first heat exchange coils 541 wound on the outer wall of the first conical segment cylinder 54, and the first straight segment heat exchange pipe assembly comprises a plurality of straight segment heat exchange pipes arranged at intervals around the outer wall of the first body segment columnar cylinder 53. The upper ends of all the first straight segment heat exchange pipes are in communication with a first straight segment heat exchange upper header 531, and the lower ends of all the first straight segment heat exchange pipes are in communication with a first straight segment heat exchange lower header 532. The first straight segment heat exchange upper header 531 and the first straight segment heat exchange lower header 532 are arranged around the upper and lower ends of the outer wall of the first body segment columnar cylinder 53. The second gas-solid coupling separator 6 comprises a second body segment columnar cylinder 63 and a second conical segment cylinder 64, and the second separator heat exchange pipe cooling mechanism comprises a second heat exchange coil assembly and a second straight segment heat exchange pipe assembly. The second heat exchange coil assembly comprises second heat exchange coils 641 wound on the outer wall of the second conical segment cylinder 64, and the second straight segment heat exchange pipe assembly comprises a plurality of second straight segment heat exchange pipes arranged at intervals around the outer wall of the second body segment columnar cylinder 63. The upper ends of all the second straight segment heat exchange pipes are in communication with a second straight segment heat exchange upper header 631, and the lower ends of all the second straight segment heat exchange pipes are in communication with a second straight segment heat exchange lower header 632. The second straight segment heat exchange upper header 631 and the second straight segment heat exchange lower header 632 are arranged around the upper and lower ends of the outer wall of the second body segment columnar cylinder 63. For simplicity of the view, Figure 2 The first straight segment heat exchange pipes and the second straight segment heat exchange pipes are not shown in the figure.

[0034] In this embodiment, the inlet ends of the first heat exchange coils 541 in the first heat exchange coil assembly and the inlet ends of the second heat exchange coils 641 in the second heat exchange coil assembly are in communication with the waste heat drum 9 through the fourth downcomer 94. The outlet ends of the first heat exchange coils 541 in the first heat exchange coil assembly and the outlet ends of the second heat exchange coils 641 in the second heat exchange coil assembly are in communication with the waste heat drum 9 through the seventh upcomer 90.

[0035] The first straight segment heat exchange upper header 531 is in communication with the waste heat drum 9 through an eighth upcomer 5311, and the second straight segment heat exchange upper header 631 is in communication with the waste heat drum 9 through a ninth upcomer 6311. The first straight segment heat exchange lower header 533 and the second straight segment heat exchange lower header 633 are in communication with the waste heat drum 9 through the fifth downcomer 95.

[0036] The bottom of the first gas-solid coupling separator 5 is provided with a first dust hopper 502, the bottom of the first dust hopper 502 is connected with a first dust hopper output pipe 503, the first dust hopper output pipe 503 is connected with a first dust cooler 504, and the first dust cooler 504 is connected with a first dust bin 505; the bottom of the second gas-solid coupling separator 6 is provided with a second dust hopper 602, the bottom of the second dust hopper 602 is connected with a second dust hopper output pipe 603, the second dust hopper output pipe 603 is connected with a second dust cooler 604, and the second dust cooler 604 is connected with a second dust bin 605.

[0037] First, the structure of the original converter outlet flue waste heat recovery system of the traditional converter gas outlet is introduced. The original converter outlet flue waste heat recovery system includes: the original water-cooled vaporization structure converter outlet flue 200 connected with the converter gas outlet and the original first steam drum 100, the water circulation between the converter outlet flue 200 and the first steam drum 100 is realized through the riser and the downcomer, the last section of the converter outlet flue 200 is the last section flue 2, the last section flue 2 is communicated with the evaporative cooler 300, the last section flue 2 and the evaporative cooler 300 both use the spraying method to spray and cool the high-temperature coal gas, that is, the LT method is used for treatment. The output end of the evaporative cooler gas output pipe 3002 at the bottom of the evaporative cooler 300 is communicated with the coal gas discharge pipe 40. The coal gas discharge pipe 40 is connected with the electrostatic dust removal system.

[0038] The reconstruction process in the application is as follows: before the reconstruction is completed, the high-temperature coal gas with a temperature of about 1450℃ generated by the converter is cooled to about 900℃ through the converter outlet flue 200, then enters the last section flue 2, and the high-temperature coal gas is sprayed and cooled in the last section flue 2, then enters the evaporative cooler 300 through the waste heat recovery inlet section flue tee 1 and the connecting section 12, and is sprayed and cooled to about 200℃ in the evaporative cooler 300. The coal gas sprayed and cooled in the evaporative cooler 300 enters the electrostatic dust removal system through the evaporative cooler gas output pipe 3002 and the coal gas discharge pipe 40 for further dust removal. That is, before the reconstruction is completed, the original converter outlet flue waste heat recovery system is used for heat recovery and high-temperature coal gas treatment. Obviously, the temperature of the flue gas is rapidly reduced from about 900℃ to about 200℃, and the heat energy is completely wasted, and a large amount of sludge and sewage is produced by the spraying and cooling, which causes environmental pollution.

[0039] Since the newly added last section flue waste heat recovery system is outside the original converter outlet flue waste heat recovery system, the construction, installation and debugging of the last section flue waste heat recovery system do not affect the normal work of the converter, the converter outlet flue and the original converter outlet flue waste heat recovery system.

[0040] After the installation of the tail flue waste heat recovery system is completed, the water-cooled cover plate 141 is removed, so that the waste heat recovery system inlet is in sealed communication with the second port of the waste heat recovery inlet section flue tee joint; the connecting section 12 and the evaporator cooler inlet 3001 are separated by the heat preservation cover plate 3003, and the evaporative cooler gas output control valve 3004 is closed, so that the evaporative cooler gas output pipe 3002 is closed. After the transformation is completed, the high-temperature gas of about 1450 DEG C generated in the converter enters the converter outlet flue 200 from the flue gas outlet of the converter, and then enters the tail flue 2, at this time the temperature is reduced to about 900 DEG C. The high-temperature gas in the tail flue 2 in the application is not sprayed directly through the waste heat recovery inlet section flue tee joint 1 in sequence through the cooling flue first section 31 and the cooling flue second section 32, and the high-temperature gas releases heat in the cooling flue first section 31 and the cooling flue second section 32, thereby recovering heat. The temperature of the gas discharged from the cooling flue second section 32 is 650 DEG C to 700 DEG C. Then it is divided into two ways through the adiabatic transition flue tee joint 4, one way enters the first gas-solid coupling separator 5, and the other way enters the second gas-solid coupling separator 6.

[0041] The high-temperature gas realizes preliminary dust removal in the first gas-solid coupling separator 5 and the second gas-solid coupling separator 6. The high-temperature gas transfers heat to the first separator heat exchange pipe cooling mechanism and the second separator heat exchange pipe cooling mechanism. The dust in the first gas-solid coupling separator 5 is collected in the first dust collector 502, and the dust of the first dust collector 502 enters the first dust cooler 504 through the first dust collector output pipe 503 and is cooled to enter the first dust bin 505. The dust in the second gas-solid coupling separator 6 is collected in the second dust collector 602, and the dust of the second dust collector 602 enters the second dust cooler 604 through the second dust collector output pipe 603 and is cooled to enter the second dust bin 605.

[0042] The high-temperature gas in the first gas-solid coupling separator 5 after preliminary dust removal enters the flue gas inlet end of the first quenching fire tube heat exchanger 7 through the first connecting flue, and then enters the heat exchange tube bundle in the first quenching fire tube heat exchanger 7 for rapid cooling. The high-temperature gas in the second gas-solid coupling separator 6 after preliminary dust removal enters the flue gas inlet end of the second quenching fire tube heat exchanger 8 through the second connecting flue, and then enters the heat exchange tube bundle in the second quenching fire tube heat exchanger 8 for rapid cooling. The high-temperature gas is further cooled to 200 DEG C while being further dusted in the first quenching fire tube heat exchanger 7 and the second quenching fire tube heat exchanger 8. The cooled gas is gathered from the first flue gas output pipe 71 of the first quenching fire tube heat exchanger 7 and from the second flue gas output pipe 81 of the second quenching fire tube heat exchanger 8, and then is transported into the electrostatic dust removal system for further dust removal through the gas discharge pipe 40. The dust in the first quenching fire tube heat exchanger 7 and the second quenching fire tube heat exchanger 8 is respectively discharged to the heat exchanger dust removal main pipe 20 through the first dust discharge pipe 72 and the second dust discharge pipe 82, and then is discharged outward.

[0043] As can be seen from the above, the application provides a waste heat recovery transformation process for the end section of the converter outlet flue. The newly added end section flue waste heat recovery system is outside the original converter outlet flue waste heat recovery system. The construction, installation and debugging of the end section flue waste heat recovery system do not affect the normal work of the converter, the converter outlet flue and the original converter outlet flue waste heat recovery system. After the installation of the end section flue waste heat recovery system is completed, only the waste heat recovery system inlet needs to be sealed and communicated with the second port of the waste heat recovery system inlet section flue tee joint, the connecting section 12 needs to be separated from the evaporator cooler inlet 3001, and the evaporative cooler gas output pipe 3002 needs to be closed. The new end section flue waste heat recovery system can be operated. The switching time of the new system is very short and very convenient. By using the new end section flue waste heat recovery system, the traditional LT method is replaced, and full dry method treatment is realized. Not only can the heat energy of the high-temperature gas at 900℃ in the end section flue 2 be effectively recovered, thereby avoiding heat energy loss and reducing steelmaking cost, but also the pollution of the environment caused by a large amount of sludge due to LT method treatment can be avoided. In addition, since no spraying treatment is performed, the enthalpy value of the gas product can be effectively improved, thereby improving the quality of the gas product.

Claims

1. A waste heat recovery retrofit process for the terminal section of a converter outlet flue, characterized in that: First, install a waste heat recovery inlet flue tee. The waste heat recovery inlet flue tee includes a horizontally arranged flue body with a connecting section at the bottom. The two horizontal ports of the flue body are the first port and the second port, respectively. Seal the first port to the outlet of the last section of the converter outlet flue, block the second port, and seal the connecting section to the top evaporator inlet of the evaporator cooler. Before the renovation was completed, the high-temperature gas generated by the converter was sent from the converter outlet flue to the last section of the converter outlet flue. After being sprayed and cooled in the last section of the flue, the high-temperature gas entered the evaporative cooler for spray cooling through the waste heat recovery inlet section flue tee and connecting section. The heat energy of the high-temperature gas was recovered by the original converter outlet flue waste heat recovery system. The high-temperature gas was treated using the LT method.

2. An additional terminal flue waste heat recovery system is added. The terminal flue waste heat recovery system includes a waste heat recovery system inlet, a waste heat recovery system outlet, a waste heat steam drum, and a waste heat recovery mechanism. The installation of the terminal flue waste heat recovery system will not affect the normal operation of the converter, the converter outlet flue, or the original converter outlet flue waste heat recovery system.

3. After the waste heat recovery system of the final section of the flue is installed, seal and connect the inlet of the waste heat recovery system to the second port of the tee of the waste heat recovery inlet section of the flue; isolate the connecting section from the top inlet of the evaporative cooler and seal the gas output pipe of the evaporative cooler at the bottom of the evaporative cooler; after the modification is completed, the high-temperature gas generated by the converter enters the final section of the flue through the converter outlet flue and is not sprayed, but enters the waste heat recovery mechanism through the second port of the tee of the waste heat recovery inlet section of the flue and the inlet of the waste heat recovery system for dry treatment and cooling, and then is discharged from the outlet of the waste heat recovery system.

2. The waste heat recovery modification process for the terminal section of the converter outlet flue as described in claim 1, characterized in that: The waste heat recovery inlet flue tee adopts a water-cooled vaporization structure. The left and right ends of the flue body are respectively equipped with an upper flue body header and a lower flue body header. The upper and lower ends of the connecting section are respectively equipped with an upper connecting section header and a lower connecting section header. The upper flue body header and the upper connecting section header are connected to the first steam drum in the original converter outlet flue waste heat recovery system through the inlet flue riser pipe. The lower flue body header is connected to a lower flue body header water inlet pipe with a first control valve. The lower connecting section header is connected to a lower connecting section header water inlet pipe with a second control valve. Both the lower flue body header water inlet pipe and the lower connecting section header water inlet pipe are connected to the inlet flue downcomer pipe. The inlet flue downcomer pipe is connected to the first steam drum in the original converter outlet flue waste heat recovery system.

3. The waste heat recovery modification process for the terminal section of the converter outlet flue according to claim 1, characterized in that: In the first step, the second port is sealed with a water-cooled cover plate; after the waste heat recovery system of the last section of the flue is installed, the water-cooled cover plate is removed so that the inlet of the waste heat recovery system is sealed and connected to the second port of the flue tee of the waste heat recovery inlet section; the connection section is separated from the top inlet of the evaporative cooler by an insulated cover plate, and the evaporative cooler gas output pipe at the bottom of the evaporative cooler is closed by the evaporative cooler gas output control valve.

4. The waste heat recovery modification process for the terminal section of the converter outlet flue as described in claim 1, characterized in that: The waste heat recovery mechanism includes: a cooling flue, the inlet of which serves as the inlet for the waste heat recovery system; an insulated transition flue tee at the outlet of the cooling flue, the insulated transition flue tee having three flue ports, one of which connects to the outlet of the cooling flue, and the other two flue ports connect to a first gas-solid coupling separator and a second gas-solid coupling separator, respectively; the top of the first gas-solid coupling separator is connected to the flue gas inlet of a vertically arranged first quench fire-tube heat exchanger via a first connecting flue; the top of the second gas-solid coupling separator is connected to the flue gas inlet of a vertically arranged second quench fire-tube heat exchanger via a second connecting flue; and the lower end of the first quench fire-tube heat exchanger is connected to... The first flue gas outlet pipe and the first ash pipe are connected to the lower end of the second quench fire tube heat exchanger. The cooling flue, the first connecting flue, and the second connecting flue all adopt a water-cooled wall vaporization flue structure. The outer wall of the first gas-solid coupling separator is equipped with a first separator heat exchange tube cooling mechanism, and the outer wall of the second gas-solid coupling separator is equipped with a second separator heat exchange tube cooling mechanism. The cooling flue, the first connecting flue, the second connecting flue, the cylinder of the first quench fire tube heat exchanger, the cylinder of the second quench fire tube heat exchanger, the first separator heat exchange tube cooling mechanism, and the second separator heat exchange tube cooling mechanism are all connected to the waste heat steam drum through several riser pipes and several downcomer pipes.

5. The waste heat recovery modification process for the terminal section of the converter outlet flue according to claim 4, characterized in that: The cooling flue includes a first cooling flue section and a second cooling flue section connected sequentially along the flue gas flow direction. The inlet of the first cooling flue section is the inlet of the waste heat recovery system. The inlet of the first cooling flue section is used for a sealed connection with the second port of the flue tee of the waste heat recovery inlet section. The outlet of the second cooling flue section is connected to the insulated transition flue tee. The first and second cooling flue sections are respectively equipped with an upper cooling flue header and a lower cooling flue header. The upper cooling flue header is connected to the waste heat steam drum through a riser pipe, and the lower cooling flue header is connected to the waste heat steam drum through a downcomer pipe.

6. The waste heat recovery modification process for the terminal section of the converter outlet flue according to claim 4, characterized in that: The first connecting flue includes a first connecting flue section 1 and a first connecting flue section 2 connected sequentially along the flue gas flow direction. The lower end of the first connecting flue section 1 is connected to the flue gas outlet of the first separator at the top of the first gas-solid coupling separator. The upward bend of the first connecting flue section 1 connects to the upper end of the first connecting flue section 2. The first connecting flue section 2 bends downward, and the lower end of the first connecting flue section 2 is connected to the flue gas inlet of the first fire tube heat exchanger of the first quench fire tube heat exchanger. The two ends of the first connecting flue section 1 are respectively provided with an upper header and a lower header. The two ends of the first connecting flue section 2 are respectively provided with an upper header and a lower header. The upper header of the first connecting flue section 1 and the upper header of the first connecting flue section 2 are respectively connected to the waste heat steam drum through riser pipes. The lower header of the first connecting flue section 1 and the lower header of the first connecting flue section 2 are respectively connected to the waste heat steam drum through downcomer pipes. The second connecting flue includes a second connecting flue section 1 and a second connecting flue section 2 connected sequentially along the flue gas flow direction. The lower end of the second connecting flue section 1 is connected to the flue gas outlet of the second separator at the top of the second gas-solid coupling separator. The second connecting flue section 1 bends upward to connect with the upper end of the second connecting flue section 2. The second connecting flue section 2 bends downward, and the lower end of the second connecting flue section 2 is connected to the flue gas inlet of the second fire tube heat exchanger of the second quench fire tube heat exchanger. The two ends of the second connecting flue section 1 are respectively provided with an upper header and a lower header. The two ends of the second connecting flue section 2 are respectively provided with an upper header and a lower header. The upper headers of the second connecting flue section 1 and the upper headers of the second connecting flue section 2 are respectively connected to the waste heat steam drum through riser pipes. The lower headers of the second connecting flue section 1 and the lower headers of the second connecting flue section 2 are respectively connected to the waste heat steam drum through downcomer pipes.

7. The waste heat recovery modification process for the terminal section of the converter outlet flue according to claim 4, characterized in that: The bottom of the first gas-solid coupling separator is provided with a first ash hopper. The bottom of the first ash hopper is connected to the first ash cooler through the first ash hopper output pipe. The first ash cooler is connected to the first ash silo. The bottom of the second gas-solid coupling separator is equipped with a second ash hopper. The bottom of the second ash hopper is connected to the second ash cooler through the second ash hopper output pipe. The second ash cooler is connected to the second ash silo.

8. The waste heat recovery modification process for the terminal section of the converter outlet flue according to claim 4, characterized in that: The first gas-solid coupling separator includes a first main body cylindrical section and a first conical section cylindrical section. The first separator heat exchange tube cooling mechanism includes a first heat exchange coil assembly and a first straight section heat exchange tube assembly. The first heat exchange coil assembly includes a first heat exchange coil wound around the outer wall of the first conical section cylindrical section. The first straight section heat exchange tube assembly includes a plurality of first straight section heat exchange tubes spaced apart around the outer wall of the first main body cylindrical section. The upper ends of all the first straight section heat exchange tubes are connected to the upper header of the first straight section heat exchange tubes. The lower ends are all connected to the lower header of the first straight section heat exchanger. The upper header and the lower header of the first straight section heat exchanger are arranged around the upper and lower ends of the outer wall of the columnar cylinder of the first body section. The inlet end of the first heat exchange coil in the first heat exchange coil assembly is connected to the waste heat steam drum through a downcomer, and the outlet end of the first heat exchange coil in the first heat exchange coil assembly is connected to the waste heat steam drum through a riser. The upper header of the first straight section heat exchanger is connected to the waste heat steam drum through a riser, and the lower header of the first straight section heat exchanger is connected to the waste heat steam drum through a downcomer. The two-gas-solid coupling separator includes a second main body cylindrical section and a second conical section cylindrical section. The heat exchange tube cooling mechanism of the second separator includes a second heat exchange coil assembly and a second straight section heat exchange tube assembly. The second heat exchange coil assembly includes a second heat exchange coil wound around the outer wall of the second conical section cylindrical section. The second straight section heat exchange tube assembly includes a plurality of second straight section heat exchange tubes spaced apart around the outer wall of the second main body cylindrical section. The upper ends of all the second straight section heat exchange tubes are connected to the upper header of the second straight section heat exchange tubes. The lower ends of both are connected to the lower header of the second straight section heat exchanger. The upper header of the second straight section heat exchanger and the lower header of the second straight section heat exchanger are arranged around the upper and lower ends of the outer wall of the columnar cylinder of the second body section. The inlet end of the second heat exchange coil in the second heat exchange coil assembly is connected to the waste heat steam drum through a downcomer. The outlet end of the second heat exchange coil in the second heat exchange coil assembly is connected to the waste heat steam drum through a riser. The upper header of the second straight section heat exchanger is connected to the waste heat steam drum through a riser. The lower header of the second straight section heat exchanger is connected to the waste heat steam drum through a downcomer.

9. The waste heat recovery modification process for the terminal section of the converter outlet flue according to claim 4, characterized in that: Both the first and second flue gas outlet pipes are connected to the main flue gas outlet pipe; the outlet of the main flue gas outlet pipe is the outlet of the waste heat recovery system; A three-way connector is installed at the output end of the evaporator gas output pipe at the bottom of the evaporator. An evaporator gas output control valve is installed on the evaporator gas output pipe. One end of the three-way connector is connected to the main gas output pipe, and the other end of the three-way connector is used to connect to the main flue gas output pipe. In the third step, after the waste heat recovery system of the final section of the flue gas duct is installed, the gas output pipe of the evaporator at the bottom of the evaporator is closed by the gas output control valve of the evaporator, and at the same time the main flue gas output pipe is connected to the three-way pipe, so that the outlet of the waste heat recovery system of the newly added final section of the flue gas duct is connected to the gas output main pipe of the original converter outlet flue gas duct waste heat recovery system.

10. The waste heat recovery modification process for the terminal section of a converter outlet flue according to claim 4, characterized in that: Both the first and second rows of ash pipes are connected to the heat exchanger dust discharge main pipe; heat exchanger dust discharge main pipe.

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