Ascending pipe waste heat utilization device and method

Abstract

The invention relates to an ascending pipe waste heat utilization device and method. The ascending pipe waste heat utilization device comprises a heated section, a heat release section, a waste heat leading-out pipeline and a working medium leading-in pipeline. The heated section is composed of a lower collecting pipe, heat exchange vertical pipes and an upper collecting pipe, the multiple heat exchange vertical pipes are embedded in the pipe wall of the ascending pipe in the circumferential direction, and fins are arranged on one sides of the heat exchange vertical pipes; the heat release section is arranged in the furnace gas pipeline and consists of a plurality of annular finned tubes; one end of the annular finned tube is connected with the upper collecting tube through a waste heat leading-out pipeline, and the other end is connected with the lower collecting tube through a working medium leading-in pipeline; and a working medium inlet is formed in the waste heat leading-out pipeline close to the heat release section. The raw gas waste heat in the ascending pipe is recovered by the circulating working medium for heating the gas before entering the coke oven, so that the use amount of the heating gas in the coke oven can be effectively reduced, and the heat efficiency is improved; the ascension pipe waste heat utilization device is simple in structure and safe to use, molten salt is adopted as a working medium, an ultrasonic descaling device is arranged, and the inner wall of the ascension pipe is not prone to scaling.

Description

Technical Field

[0001] The present invention relates to the technical field of coke oven coking, and particularly to a waste heat utilization device and method for the riser of a coke oven. Background Art

[0002] The heat losses in the coke oven coking process mainly include four parts: sensible heat of the discharged red coke, sensible heat of the raw gas, sensible heat of the flue gas in the coke oven flue, and heat dissipation from the furnace body surface. The temperature of the raw gas in the coke oven is about 650 - 750°C, and its sensible heat accounts for about 36% of the heat distribution in the coke oven. At present, the waste heat recovery technology for the raw gas in the coke oven is relatively mature and has significant economic benefits.

[0003] Installing a heat exchange device (such as a jacket or coil) on the outer wall of the coke oven riser and using heat transfer oil, water, or organic working medium to absorb the heat of the raw gas is called the waste heat utilization technology for the riser. In the actual application process of the waste heat utilization technology for the coke oven riser, it is necessary to pay attention that the riser heat exchanger needs to adopt effective measures and reasonable structures to avoid deformation and leakage. Even when the above problems occur, the working medium should be prevented from entering the coke oven carbonization chamber to ensure the safety and stability of coke oven production. At the same time, it is necessary to reasonably and effectively control the inner wall temperature of the riser (usually ≥450°C) to avoid the large condensation temperature zone of tar, so as to prevent tar and graphitization on the inner wall of the riser, resulting in blockage of the riser and the resulting environmental problems (such as smoking).

[0004] On the other hand, the traditional method for treating the raw gas in the coking industry is to spray circulating ammonia water at 70 - 75°C into the raw gas. As the circulating ammonia water absorbs heat and evaporates, the temperature of the raw gas decreases and then enters the subsequent chemical production section for recovery and treatment. This treatment process causes serious waste of the sensible heat of the raw gas. Summary of the Invention

[0005] The present invention provides a waste heat utilization device and method for the riser, which uses a circulating working medium to recover the waste heat of the raw gas in the riser and is used to heat the gas before entering the coke oven, which can effectively reduce the consumption of the heating gas in the coke oven and improve the thermal efficiency. The waste heat utilization device for the riser has a simple structure and is safe to use. It uses molten salt as the working medium and is equipped with an ultrasonic descaling device, so that the inner wall of the riser is not easily fouled.

[0006] To achieve the above object, the present invention is realized by adopting the following technical solutions:

[0007] A waste heat utilization device for a riser tube, comprising a heating section, a heat release section, a waste heat export pipeline and a working medium import pipeline; the heating section is composed of a lower header, heat exchange risers and an upper header. Both the lower header and the upper header are annular tubes. The lower header is arranged on the outer periphery of the bottom of the riser tube, and the upper header is arranged on the outer periphery of the top of the riser tube. A plurality of heat exchange risers are embedded in the wall of the riser tube along the circumferential direction. Fins are arranged on the side of the heat exchange riser facing the inside of the riser tube. The lower end of the heat exchange riser is communicated with the lower header, and the upper end of the heat exchange riser is communicated with the upper header. The heat release section is arranged in the furnace inlet gas pipeline and is composed of a plurality of annular finned tubes. Both ends of the annular finned tube extend out of the furnace inlet gas pipeline. One end is connected to the upper header through the waste heat export pipeline, and the other end is connected to the lower header through the working medium import pipeline. A working medium inlet is arranged on the waste heat export pipeline near the heat release section, and a valve is arranged at the working medium inlet.

[0008] The riser tube is composed of a cylinder body, flanges and a heat insulation layer; flanges are respectively arranged at both ends of the cylinder body, a heat insulation layer is arranged on the outer side of the cylinder body, and the heat insulation layer wraps the heat exchange risers therein; a plurality of slits are circumferentially arranged on the cylinder body, and the heat exchange risers are embedded in the slits and welded to the cylinder body, and the inner wall of the cylinder body is a smooth wall surface.

[0009] An outlet valve is arranged on the waste heat export pipeline near the upper header; an inlet valve is arranged on the working medium import pipeline near the lower header.

[0010] There are a plurality of the fins, which are arranged in a radial shape.

[0011] The heating section, the heat release section, the waste heat export pipeline and the working medium import pipeline are all made of stainless steel, and the heating section is made of heat-resistant stainless steel.

[0012] Each heat exchange riser is made of a whole seamless steel pipe.

[0013] A waste heat utilization device for a riser tube further comprises an ultrasonic descaling device; the ultrasonic descaling device consists of an ultrasonic generator, an ultrasonic transducer and a high-frequency cable. The ultrasonic generator is connected to the ultrasonic transducer through the high-frequency cable; the ultrasonic transducer is arranged on a waveguide structure, and the waveguide structure is arranged on the flange at the top of the riser tube.

[0014] A waste heat utilization method for a riser tube comprises the following processes:

[0015] 1) Weld the two flanges of the riser tube to the cylinder body, weld fins on the heat exchange risers of the heating section, and respectively weld the two ends of the heat exchange risers to the upper header and the lower header; weld the heat exchange risers to the slits opened on the cylinder body; weld the waveguide structure to the flange at the top of the riser tube; after all the welding is completed, conduct a pressure test on the assembled parts. After the pressure test is qualified, set a heat insulation layer outside the riser tube;

[0016] 2) Place multiple annular finned tubes in the exothermic section inside the gas pipeline entering the furnace, and perpendicular to the gas flow direction; weld the two ends of the annular finned tubes to the waste heat export pipeline and the working medium import pipeline respectively; connect the waste heat export pipeline to the upper header through an outlet valve, and connect the working medium export pipeline to the lower header through an inlet valve; after the connection is completed, conduct a pressure test on the working medium circulation system; after the pressure test is qualified, fill the working medium using the valve on the waste heat export pipeline;

[0017] 3) The high-temperature raw coke oven gas generated during the production process of the coke oven is led out by the riser pipe. The heating section absorbs the heat of the high-temperature raw coke oven gas and transfers it to the working medium inside the pipe through the wall of the heat exchange riser. After absorbing heat, the working medium boils and evaporates, turning into steam. Under the action of the pressure difference, the steam reaches the exothermic section along the waste heat export pipeline;

[0018] 4) In the exothermic section, the steam exchanges heat with the low-temperature gas in the gas pipeline entering the furnace. The steam condenses and releases the latent heat of vaporization outward. The condensate returns to the heating section through the working medium import pipeline under the action of gravity and exchanges heat with the raw coke oven gas again;

[0019] 5) Steps 3)-4) are carried out cyclically. The waste heat of the high-temperature raw coke oven gas is recovered using the working medium and used to heat the gas entering the furnace. The heated gas entering the furnace directly enters the coke oven for combustion.

[0020] The working medium is molten salt.

[0021] During the production process of the coke oven, start the ultrasonic descaling device to remove the impurities attached to the inner wall of the riser pipe and prevent graphite formation.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] 1) The heating section in the waste heat utilization device of the riser pipe is made of a whole seamless steel pipe, and the two ends are welded to the header, which is beneficial to reducing leakage and extending the service life; fins are provided on the inner side of the heat exchange pipes in the heating section, increasing the heat exchange area and improving the heat exchange efficiency.

[0024] 2) All the pipelines in the waste heat utilization device of the riser pipe are made of stainless steel material, which is corrosion-resistant and not easy to leak; the circulating working medium uses molten salt, which has a high operating temperature. Even if there is a leak, it does not affect the operation of the coke oven and ensures the stable operation of the coke oven.

[0025] 3) The recovered waste heat of the raw coke oven gas is exchanged with the gas before entering the coke oven, and the waste heat of the raw coke oven gas is used to indirectly heat the gas entering the furnace, increasing the temperature of the gas entering the furnace, which is beneficial to reducing the gas consumption during the production of the coke oven and improving the thermal efficiency.

[0026] 4) Use the ultrasonic descaling device to timely remove the scale on the inner wall of the riser pipe to ensure the long-term stable operation of the system. Description of the Drawings

[0027] Figure 1 is a schematic structural view of a riser waste heat utilization device according to the present invention.

[0028] Figure 2 is a top view of the heated section according to the present invention.

[0029] Figure 3 is a schematic structural view of the heat exchange riser pipe according to the present invention.

[0030] Figure 4 is Figure 3 the A-A view in

[0031] In the figure: 1. Riser pipe 101. Cylinder body 102. Flange 103. Thermal insulation layer 21. Heat exchange riser pipe 22. Fins 23. Upper header 24. Lower header 3. Inlet gas pipeline for furnace 41. Annular finned tube 42. Valve 5. Waste heat export pipeline 51. Outlet valve 6. Working medium import pipeline 61. Inlet valve 7. Ultrasonic descaling device 701. Ultrasonic generator 702. High-frequency cable 703. Ultrasonic transducer 704. Waveguide structure Specific embodiments

[0032] The following further describes the specific embodiments of the present invention with reference to the accompanying drawings:

[0033] As Figure 1 , Figure 2 shown, a riser waste heat utilization device according to the present invention includes a heated section, a heat release section, a waste heat export pipeline 5 and a working medium import pipeline 6; the heated section is composed of a lower header 24, a heat exchange riser pipe 21 and an upper header 23, both the lower header 24 and the upper header 23 are annular pipes, the lower header 24 is arranged on the outer periphery of the bottom of the riser pipe 1, and the upper header 23 is arranged on the outer periphery of the top of the riser pipe 1; a plurality of heat exchange riser pipes 21 are embedded in the wall of the riser pipe 1 along the circumferential direction, fins 22 are arranged on the side of the heat exchange riser pipe 21 facing the inside of the riser pipe 1, the lower end of the heat exchange riser pipe 21 is communicated with the lower header 24, and the upper end of the heat exchange riser pipe 21 is communicated with the upper header 23; the heat release section is arranged in the inlet gas pipeline 3 for furnace and is composed of a plurality of annular finned tubes 41; both ends of the annular finned tube 41 extend out of the inlet gas pipeline 3 for furnace, one end of which is connected to the upper header 23 through the waste heat export pipeline 5, and the other end is connected to the lower header 24 through the working medium import pipeline 6; a working medium inlet is arranged on the waste heat export pipeline 5 near the heat release section, and a valve 42 is arranged at the working medium inlet.

[0034] The riser pipe 1 is composed of a cylinder body 101, a flange 102 and a thermal insulation layer 103; flanges 102 are respectively arranged at both ends of the cylinder body 101, a thermal insulation layer 103 is arranged on the outer side of the cylinder body 101, and the thermal insulation layer 103 wraps the heat exchange riser pipe 21 therein; a plurality of slits are circumferentially formed on the cylinder body 101, the heat exchange riser pipe 21 is embedded in the slits and welded to the cylinder body 101, and the inner wall of the cylinder body 101 is a smooth wall surface.

[0035] The waste heat export pipeline 5 is provided with an outlet valve 51 near the upper header 23; the working medium import pipeline 6 is provided with an inlet valve 61 near the lower header 24.

[0036] Such as Figure 3 、 Figure 4 shown, there are multiple fin pieces 22, which are arranged in a radial shape.

[0037] The heat receiving section, the heat releasing section, the waste heat export pipeline 5 and the working medium import pipeline 6 are all made of stainless steel, and the heat receiving section is made of heat-resistant stainless steel.

[0038] Each heat exchange riser 21 is made of a whole seamless steel pipe.

[0039] The waste heat utilization device of the riser pipe described in the present invention further includes an ultrasonic descaling device 7; the ultrasonic descaling device 7 includes an ultrasonic generator 701, an ultrasonic transducer 703 and a high-frequency cable 702. The ultrasonic generator 701 is connected to the ultrasonic transducer 703 through the high-frequency cable 702; the ultrasonic transducer 703 is arranged on a waveguide structure 704, and the waveguide structure 704 is arranged on the flange at the top of the riser pipe 1.

[0040] The waste heat utilization method of the riser pipe described in the present invention includes the following processes:

[0041] 1) Weld the two flanges 102 of the riser pipe 1 to the cylinder body 101, weld the fin pieces 22 on the heat receiving section of the heat exchange riser 21, and weld the two ends of the heat exchange riser 21 to the upper header 23 and the lower header 24 respectively; weld the heat exchange riser 21 to the slit opened on the cylinder body 101; weld the waveguide structure 704 to the flange at the top of the riser pipe 1; after all welding is completed, conduct a pressure test on the assembled part, and set a heat preservation layer 103 outside the riser pipe 1 after the pressure test is qualified;

[0042] 2) Place multiple annular finned tubes 41 of the heat releasing section in the furnace inlet gas pipeline 3 and perpendicular to the gas flow direction; weld the two ends of the annular finned tube 41 to the waste heat export pipeline 5 and the working medium import pipeline 6 respectively; connect the waste heat export pipeline 5 to the upper header 23 through the outlet valve 51, and connect the working medium export pipeline 6 to the lower header 24 through the inlet valve 61; after the connection is completed, conduct a pressure test on the working medium circulation system; after the pressure test is qualified, fill the working medium by using the valve 42 on the waste heat export pipeline 5;

[0043] 3) The high-temperature raw coke oven gas generated during the production process of the coke oven is exported from the riser pipe 1. The heat receiving section absorbs the heat of the high-temperature raw coke oven gas and transfers it to the working medium inside the pipe through the pipe wall of the heat exchange riser 21. After absorbing heat, the working medium boils and evaporates and turns into steam. The steam reaches the heat releasing section along the waste heat export pipeline 5 under the action of the pressure difference;

[0044] 4) In the exothermic section, the vapor exchanges heat with the low-temperature coal gas in the coal gas pipeline 3 entering the furnace. The vapor condenses and releases the latent heat of vaporization outward. The condensate returns to the heating section through the working medium introduction pipeline 6 under the action of gravity and exchanges heat with the raw coal gas again;

[0045] 5) Steps 3)-4) are carried out cyclically. The waste heat of the high-temperature raw coal gas is recovered by using the working medium and used to heat the coal gas entering the furnace. The heated coal gas entering the furnace directly enters the coke oven for combustion.

[0046] The working medium is molten salt.

[0047] During the production process of the coke oven, the ultrasonic descaling device 7 is started to remove the impurities attached to the inner wall of the riser pipe 1 and prevent graphite from forming.

[0048] For the riser pipe waste heat utilization device of the present invention, all the main components (including the heat exchange riser pipe 21, fins 22, upper header 23, lower header 24, outlet valve 51, inlet valve 61, waste heat export pipeline 5, working medium introduction pipeline 6, annular finned tube 41 and valve 42, etc.) are made of stainless steel. Among them, the heat exchange riser pipe 21 is made of a whole seamless steel pipe (without seams), and both ends are welded to the corresponding headers, aiming to reduce leakage and extend the service life. Fins 22 are welded on one side of the heat exchange riser pipe 21 located inside the riser pipe 1 (as shown in Figure 3 、 Figure 4 ), and the side wall of the cylinder body of the riser pipe 1 also serves as a fin, effectively increasing the heat exchange area and improving the heat exchange efficiency. The heat exchange element in the exothermic section is an annular finned tube 41 (a steel pipe with annular fins). The heating section and the exothermic section are connected by the waste heat export pipeline 5 and the working medium introduction pipeline 6 to form a working medium circulation system. The valve 42 on the waste heat export pipeline 5 is used to fill the working medium on-site, and through this valve 42, operations such as vacuum pumping or extraction of non-condensable gases can also be carried out to realize on-site regeneration of the working medium and extend its service life.

[0049] The working medium adopted in the present invention is nitrate or other molten salts.

[0050] For the cylinder body 101 of the riser pipe 1 of the present invention, a seamless steel pipe is used. Multiple slits are longitudinally opened on the cylinder body 101, and the size of the slits is matched with the installation size of the heat exchange riser pipe 21 to ensure that the inner wall of the riser pipe 1 is smooth after welding; the welding of the flange 102 and the cylinder body 101 is carried out inside the cylinder body 101 and ground flat after welding to ensure that the weld is smooth. Since the flange 102 and the cylinder body 101 are directly in contact with the high-temperature raw coal gas, they are both made of heat-resistant metal materials.

[0051] As described above, it is only the preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, making equivalent replacements or changes should be covered within the protection scope of the present invention.

Claims

1. A riser waste heat utilization device, characterized in that, It includes a heating section, a heat release section, a waste heat export pipeline and a working medium import pipeline; the heating section is composed of a lower header, heat exchange risers and an upper header. Both the lower header and the upper header are annular pipes. The lower header is arranged on the outer periphery of the bottom of the riser pipe, and the upper header is arranged on the outer periphery of the top of the riser pipe. A plurality of heat exchange risers are embedded in the wall of the riser pipe along the circumferential direction. Fins are arranged on the side of the heat exchange riser facing the inside of the riser pipe. The lower end of the heat exchange riser is communicated with the lower header, and the upper end of the heat exchange riser is communicated with the upper header. The heat release section is arranged in the furnace inlet gas pipeline and is composed of a plurality of annular finned pipes. Both ends of the annular finned pipe extend out of the furnace inlet gas pipeline. One end is connected to the upper header through the waste heat export pipeline, and the other end is connected to the lower header through the working medium import pipeline. A working medium inlet is arranged on the waste heat export pipeline near the heat release section, and a valve is arranged at the working medium inlet.

2. The waste heat utilization device for the riser pipe according to claim 1, characterized in that, The riser pipe is composed of a cylinder body, flanges and a heat insulation layer; flanges are respectively arranged at both ends of the cylinder body, and a heat insulation layer is arranged on the outer side of the cylinder body. The heat insulation layer wraps the heat exchange riser in it. A plurality of slits are circumferentially arranged on the cylinder body, and the heat exchange riser is embedded in the slits and welded to the cylinder body. The inner wall of the cylinder body is a smooth wall surface.

3. The waste heat utilization device for the riser pipe according to claim 1, wherein An outlet valve is arranged on the waste heat export pipeline near the upper header; an inlet valve is arranged on the working medium import pipeline near the lower header.

4. The waste heat utilization device of a riser pipe according to claim 1, characterized in that, The fins are multiple and are arranged in a radial shape.

5. The waste heat utilization device of a riser pipe according to claim 1, wherein The heating section, the heat release section, the waste heat export pipeline and the working medium import pipeline are all made of stainless steel, and the heating section is made of heat-resistant stainless steel.

6. The waste heat utilization device for the riser pipe according to claim 1, characterized in that, Each heat exchange riser is made of a whole seamless steel pipe.

7. The waste heat utilization device for the riser pipe according to claim 1, characterized in that, It also includes an ultrasonic descaling device; the ultrasonic descaling device is composed of an ultrasonic generator, an ultrasonic transducer and a high-frequency cable. The ultrasonic generator is connected to the ultrasonic transducer through the high-frequency cable. The ultrasonic transducer is arranged on a waveguide structure, and the waveguide structure is arranged on the flange at the top of the riser pipe.

8. A method for utilizing the waste heat of a riser pipe, which is realized by the riser pipe waste heat utilization device described in any one of claims 1 to 7, characterized in that, It includes the following processes: 1) Weld the two flanges of the riser pipe to the cylinder body, weld fins on the heat exchange risers in the heating section, and weld the two ends of the heat exchange risers to the upper header and the lower header respectively; weld the heat exchange risers to the slits opened on the cylinder body; weld the waveguide structure to the flange at the top of the riser pipe. After all the welding is completed, conduct a pressure test on the assembled parts. After the pressure test is qualified, set a heat insulation layer outside the riser pipe. 2) Place a plurality of annular finned pipes in the furnace inlet gas pipeline in the heat release section and perpendicular to the gas flow direction; weld the two ends of the annular finned pipes to the waste heat export pipeline and the working medium import pipeline respectively; connect the waste heat export pipeline to the upper header through the outlet valve, and connect the working medium export pipeline to the lower header through the inlet valve. After the connection is completed, conduct a pressure test on the working medium circulation system. After the pressure test is qualified, fill the working medium by using the valve on the waste heat export pipeline. 3) The high-temperature raw coke oven gas generated during the production process of the coke oven is exported from the riser pipe. The heating section absorbs the heat of the high-temperature raw coke oven gas and transfers it to the working medium in the pipe through the wall of the heat exchange riser. After the working medium absorbs heat, it boils and evaporates and turns into steam. The steam reaches the heat release section along the waste heat export pipeline under the action of the pressure difference. 4) In the exothermic section, the steam exchanges heat with the low-temperature coal gas in the coal gas pipeline entering the furnace. The steam condenses and releases the latent heat of vaporization outward. The condensate returns to the heating section through the working medium introduction pipeline under the action of gravity and exchanges heat with the raw coal gas again; 5) Steps 3) - 4) are carried out cyclically. The waste heat of the high-temperature raw coal gas is recovered by using the working medium and used to heat the coal gas entering the furnace. The heated coal gas entering the furnace directly enters the coke oven for combustion.

9. A method for utilizing waste heat of a riser according to claim 8, characterized in that, The working medium is molten salt.

10. A method for utilizing waste heat of a riser tube according to claim 8, characterized in that, During the production process of the coke oven, start the ultrasonic descaling device to remove the impurities adhering to the inner wall of the riser pipe and prevent graphite formation.

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