A preheating device and preheating process for a high-temperature, oily and dusty combustible gas dust collector

Abstract

The present invention relates to a preheating device and a preheating process of a high-temperature, oil- and dust-containing combustible gas dust collector, which belongs to the technical field of gas dust removal. Specifically, the smoke chamber of a hot blast furnace is connected with a replacement medium air inlet pipe, the smoke outlet of the hot blast furnace is connected with a first circulation pipe, the first circulation pipe is connected with the dust-containing gas inlet pipe, a third shut-off valve is installed on the first circulation pipe, an air inlet of a circulation fan is connected with a second circulation pipe, the second circulation pipe is connected with a clean gas outlet pipe, a fourth shut-off valve is installed on the second circulation pipe, the air outlet of the circulation fan is connected with the smoke chamber of the hot blast furnace through the third circulation pipe, a fifth shut-off valve is installed on the third circulation pipe, the first circulation pipe is also connected with a first vent pipe, the first vent pipe is installed with a first vent valve, the third circulation pipe is also connected with a second vent pipe, and the second vent pipe is installed with a second vent valve. The present invention can effectively improve the service life of the dust collector and improve the dust removal efficiency.

Description

Technical Field

[0001] The invention relates to a preheating device for a high-temperature, oil- and dust-containing combustible gas dust collector and a preheating process thereof, belonging to the technical field of gas dust removal. Background Art

[0002] In the process of realizing the graded and quality-based utilization of coal, especially low-rank coal, by low-temperature pyrolysis, high-temperature oil and gas containing a large amount of fine coal powder is produced. In order to effectively utilize this high-temperature oil and gas, the dust removal of the high-temperature oil and gas must be solved.

[0003] In the research and practice of filtering and dust removal of high-temperature oily and dusty combustible gas, people have tried many methods. Now scientific research and production personnel tend to use filter element tubular structure to filter high-temperature dusty gas to achieve gas-solid separation and gas purification. The filtered dusty gas enters the clean air chamber, and the dust is filtered outside the filter element. As the dust continues to increase, the dust accumulated on the surface of the filter element is removed in time, and the dust falls into the ash hopper and then discharged through the ash discharge outlet at the bottom of the filter, achieving good dust removal benefits. However, the complex process of high-temperature oily and dusty combustible gas will condense when it is cooled, and then adhere to the surface of the filter element, affecting the smooth progress of the process, so preheating of the dust collector is very important.

[0004] The Chinese patent with patent announcement number 102721075B discloses a device and method for preheating the interior of a dust collector. The device is arranged between a boiler and an induced draft fan to circulate and heat the dust collector, so that during the start-up of the boiler, the air circulating in the device is heated by the exhaust gas of the boiler, and the preheating of the interior of the dust collector is achieved by the circulation of hot air inside the dust collector. The boiler, the dust collector and the induced draft fan are connected through an air duct. The method uses the exhaust heat energy of the boiler in the ignition stage to preheat the interior of the dust collector, and uses the exhaust heat energy of the boiler in the ignition stage to preheat the ash hopper of the dust collector, so as to eliminate the condensation phenomenon inside the dust collector that may occur during the ignition stage of the boiler. However, its preheating temperature is relatively low, and it is difficult to apply to gases containing coal tar and other gases that have strict requirements on the internal temperature of the dust collector, and it is difficult to ensure the safety performance of gases with combustible components.

[0005] The Chinese patent with the patent announcement number of 103961955B discloses a dust collector preheating process for filtering combustible dust-containing gas, which proposes a preheating method for the dust collector, namely, the dust collector exhausts cold air stage, the heating stage and the gas replacement adjustment stage. In the cold air exhaust stage, high-temperature gas is input through the hot air duct to exhaust the low-temperature gas in the dust collector. After the low-temperature gas is exhausted, the heating stage is entered. After the temperature is raised to above 290°C, the gas replacement adjustment is performed. The replacement adjustment stage makes the oxygen content in the dust collector <1.5% after adjustment. After the oxygen content in the dust collector is adjusted to a safe range in the gas replacement adjustment stage, the conventional filtering and dust removal process is entered. This method has the following problems: 1. By introducing high-temperature gas to exhaust the low-temperature gas in the dust collector, the first is that the equipment heats up sharply, causing rapid thermal expansion and contraction, which has destructive consequences for the equipment. The second is that the air in the dust collector is not replaced and the high-temperature gas is introduced, which will cause the filter element, especially the metal filter element, to oxidize, affecting the use effect and life of the filter element; 2. The oxygen content is not controlled in the heating stage until the oxygen content is replaced in the final replacement stage. Since the heating rate needs to be controlled during the preheating stage, the preheating process is a long stage, which takes at least more than ten hours. Therefore, if the oxygen content is not controlled during this process, it will inevitably cause continuous oxidation of the filter element, especially the metal filter element. The more severe the oxidation is in the final stage, which will eventually affect the use effect and service life of the filter element.

[0006] In summary, there is an urgent need to disclose a dust collector preheating process suitable for dry purification and dust removal of coal gas for filtering high-temperature oily and dusty combustible gas. Summary of the invention

[0007] In order to solve the technical problems existing in the prior art, the present invention provides a preheating device and a preheating process for a high-temperature oil- and dust-containing combustible gas dust collector, which can effectively prolong the service life of the dust collector and improve the dust removal efficiency.

[0008] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is a preheating device for a high-temperature, oil-containing and dust-containing combustible gas dust collector, comprising a dust collector, a hot blast furnace, a blower and a circulating fan, the air inlet end of the dust collector is provided with a dust-containing gas inlet pipe, the air outlet end is provided with a clean gas outlet pipe, the dust-containing gas inlet pipe and the clean gas outlet pipe are respectively provided with a first shut-off valve and a second shut-off valve, the smoke chamber of the hot blast furnace is connected with a replacement medium inlet pipe, the smoke outlet of the hot blast furnace is connected with a first circulating pipe, the first circulating pipe is connected with the dust-containing gas inlet pipe, and the connection point is located at the rear of the outlet of the first shut-off valve, the first circulating pipe is installed with a third shut-off valve, the The air inlet of the circulation fan is connected to the second circulation pipe, the second circulation pipe is connected to the clean air outlet pipe, and the connection point is located at the front end of the inlet of the second cut-off valve, the second circulation pipe is installed with a fourth cut-off valve, the air outlet of the circulation fan is connected to the smoke chamber of the hot blast furnace through the third circulation pipe, the third circulation pipe is installed with a fifth cut-off valve, the first circulation pipe is also connected to the first vent pipe, and the connection point is located at the front end of the inlet of the third cut-off valve, the first vent valve is installed on the first vent pipe, the third circulation pipe is also connected to the second vent pipe, and the connection point is located at the front end of the inlet of the fifth cut-off valve, the second vent valve is installed on the second vent pipe.

[0009] Preferably, the air outlet of the circulating fan is also equipped with a temperature sensor and an oxygen sensor, a temperature sensor and an oxygen sensor are installed between the hot air furnace and the first relief valve, and a temperature sensor and an oxygen sensor are installed at the front end of the first relief pipe.

[0010] Preferably, the number of the dust collectors is one or more than two, and the multiple dust collectors are arranged in parallel, and the dust-containing gas inlet pipe and the clean gas outlet pipe of the dust collector are respectively connected to the first circulation pipe and the second circulation pipe through pipelines, and a shut-off valve is provided on the pipeline.

[0011] Preferably, a heat-insulating layer is provided on the inner wall of the dust collector and on the outside of the first circulation pipe, the second circulation pipe and the third circulation pipe.

[0012] A preheating process for a high-temperature oil- and dust-containing combustible gas dust collector, the process comprising two stages, namely a replacement stage and a heating stage, wherein the replacement stage is used to replace the oxygen-containing air in the dust collector; and the heating stage is used to heat and preheat the dust collector in a low-oxygen environment;

[0013] In the replacement stage, the first shut-off valve, the second shut-off valve, the fifth shut-off valve and the first relief valve are closed, the third shut-off valve, the fourth shut-off valve and the second relief valve are opened, and the circulating fan is started. At this time, the replacement medium with no oxygen or low oxygen content enters the dust collector through the replacement medium inlet pipe and the first circulation pipe, mixes with the oxygen-containing air in the dust collector, and then is discharged through the second circulation pipe and the second relief pipe;

[0014] When the oxygen content in the mixed gas is lower than 1.5%, the replacement stage ends and the temperature rise stage begins. The first relief valve is opened, the third shut-off valve, the second relief valve and the circulating fan are closed, the delivery of the replacement medium without oxygen or with low oxygen content is stopped, and at the same time, combustible gas is introduced into the hot blast furnace, the blower is turned on, ignition is started and the air-fuel ratio is adjusted, and then the replacement medium without oxygen or with low oxygen content is introduced into the hot blast furnace to cool the flue gas, until the flue gas temperature of the hot blast furnace is 80°C and the oxygen content is less than 1.5%;

[0015] Then open the third shut-off valve and the fifth shut-off valve, start the circulating fan, and gradually close the first relief valve to allow the hot flue gas to preheat the dust collector to form a circulation loop; thereafter, adjust the hot blast furnace power every hour to increase the hot flue gas temperature at the hot blast furnace outlet at a heating rate of 50-100°C / h, and at the same time control the oxygen content to be less than 1.5%, and the excess hot flue gas is discharged from the second relief valve;

[0016] When the temperature reaches the end temperature, stop preheating, quickly close the circulating fan, blower, the third shut-off valve and the fourth shut-off valve, stop delivering the replacement medium and combustible gas with no oxygen or low oxygen content, then open the first shut-off valve and the second shut-off valve to enter the normal filtration stage.

[0017] Preferably, the oxygen-free or low-oxygen replacement medium is nitrogen, carbon dioxide, or hot flue gas with an oxygen content of less than 1.5%.

[0018] Preferably, the terminal temperature of the heating stage is 300-700°C.

[0019] Preferably, the oxygen content in the dust collector is controlled between 0.6% and 1%.

[0020] Compared with the prior art, the present invention has the following technical effects: the present invention adopts the method of first replacing and then heating to preheat the dust collector. In the replacement stage, an oxygen-free or low-oxygen content replacement medium is used to replace the oxygen-containing air inside the dust collector, so that the oxygen content of the air in the dust collector is less than 1.5%; then the dust collector is heated and preheated, and the air-fuel ratio of the hot blast furnace is adjusted during the heating process to ensure that the air is fully burned. The high-temperature flue gas generated by the combustion is then temperature-controlled by the oxygen-free or low-oxygen content replacement medium, so that the temperature of the flue gas entering the dust collector gradually increases until it reaches the preheating terminal temperature. In this way, the damage to the filter element caused by excessive oxygen content in the hot flue gas during the preheating process is avoided, and the high-temperature dust-containing, oil-containing and combustible gas is ensured to be safely filtered after the preheating is completed. At the same time, controlling the oxygen content can effectively avoid oxidation of the filter element, extend the service life of the dust collector, and improve the dust removal efficiency.

[0021] The present invention is scientifically and rigorously designed, and has strong operability. It has a good effect when used in the preheating link of the dust collector, and provides a specific process flow of the preheating link. Combined with long-term production and exploration, it has well realized the innovation of the preheating process of the dust collector used to filter high-temperature dust-containing, oil-containing and combustible gases, and ensured the safety of the equipment, and further ensured the use effect and service life of the equipment. Taking into account the equipment investment and product thermal energy utilization, this preheating process is suitable for filtering high-temperature dust-containing, oil-containing and combustible gases, especially for the preheating of filter tube dust collectors containing high-temperature oil-containing, dust-containing and combustible media produced by pyrolysis of low-rank coal, biomass, oil shale, etc. It can better ensure that the filter element has a good filtering effect during normal filtration, and the filter element, a key component of the dust collector, has a long service life and high economic benefits, and has a good promotion and use value. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of embodiment 1 of the present invention.

[0023] Figure 2 It is a structural diagram of the second embodiment of the present invention. DETAILED DESCRIPTION

[0024] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0025] Embodiment 1

[0026] like Figure 1As shown, a preheating device for a high-temperature, oily and dusty combustible gas dust collector comprises a dust collector 1, a hot blast furnace 2, a blower 3 and a circulating fan 4. The air inlet end of the dust collector 1 is provided with a dust-containing gas inlet pipe 5, and the air outlet end is provided with a clean gas outlet pipe 6. The dust-containing gas inlet pipe 5 and the clean gas outlet pipe 6 are respectively provided with a first shut-off valve 7 and a second shut-off valve 8. The smoke chamber of the hot blast furnace 2 is connected with a replacement medium inlet pipe 9, and the smoke outlet of the hot blast furnace 2 is connected with a first circulating pipe 10. The first circulating pipe 10 is connected to the dust-containing gas inlet pipe 5, and the connection point is located at the rear of the outlet of the first shut-off valve 7. The first circulating pipe 10 is installed with a third shut-off valve 11. The air inlet of the circulating fan 4 is connected with a second circulating pipe 12, and the second circulating pipe 12 is connected to the clean gas outlet pipe 6. The connection point is located at the front end of the inlet of the second cut-off valve 8, the second circulation pipe 12 is equipped with a fourth cut-off valve 13, the air outlet of the circulation fan 4 is connected to the smoke chamber of the hot blast furnace 2 through the third circulation pipe 14, the third circulation pipe 14 is equipped with a fifth cut-off valve 15, the first circulation pipe 10 is also connected to the first vent pipe 16, and the connection point is located at the front end of the inlet of the third cut-off valve 11, the first vent pipe 16 is equipped with a first vent valve 17, the main pipeline in front of the first vent valve is equipped with a temperature sensor and an oxygen sensor, the third circulation pipe 14 is also connected to the second vent pipe 18, and the connection point is located at the front end of the inlet of the fifth cut-off valve, the second vent pipe 18 is equipped with a second vent valve 19, and the air outlet of the circulation fan 4 is also equipped with a temperature sensor and an oxygen sensor.

[0027] The hot blast furnace, circulation pipe and circulation fan in this embodiment can be fixed on the periphery of the dust collector by the supporting mechanism, making the layout more reasonable. The hot blast furnace and the circulation fan are connected in series on the circulation pipe, and the circulation fan is arranged at the air inlet end of the hot blast furnace to provide circulation power for the entire preheating system. The output end of the flue gas duct of the hot blast furnace is connected to the dust-containing gas inlet pipe of the dust collector, which simplifies the preheating system of the dust collector. The clean air chamber of the dust collector is connected to the clean air outlet pipe, and the clean air outlet pipe is connected to the circulation fan through the second circulation pipe, so as to realize the circulation heating of the hot flue gas of the heating dust collector, which is of great significance for improving the preheating speed of the system and avoiding the waste of heat energy caused by the emission. A displacement medium inlet pipe is provided in front of the hot blast furnace, and an inert gas is introduced into the displacement medium inlet pipe to replace the air in the dust collector by the inert gas. At the same time, the introduction of inert gas is also a necessary safety guarantee during the ignition process of the hot blast furnace. The first vent pipe is set at the output end of the hot blast furnace. The main pipeline in front of the first vent pipe is equipped with a temperature sensor and an oxygen sensor. When the dust collector preheating system adjusts the temperature, oxygen content and pressure of the hot flue gas, the substandard gas is discharged through the inlet and outlet pipe when the dust collector is preheated, so as to achieve better control of the oxygen content of the hot flue gas, avoid the damage to the filter element caused by excessive oxygen content in the hot flue gas during the preheating process, and ensure that high-temperature dust-containing, oil-containing and combustible gas is safely filtered after the preheating is completed. A second vent pipe is set between the output end of the circulating fan and the hot blast furnace to release the excess hot flue gas in the system, and the temperature sensor and oxygen content sensor are used to adjust the operation of the hot blast furnace to ensure the safe operation of the system; valves are set on the first vent pipe and the second vent pipe, which are opened and adjusted when venting is required, and closed when venting is not required.

[0028] Among them, a heat preservation layer is arranged on the inner wall of the dust collector 1 and the outside of the first circulation pipe 10, the second circulation pipe 12 and the third circulation pipe 14. The heat preservation layer can reduce the heat loss of the system and improve the preheating effect of the dust collector.

[0029] The specific preheating process is as follows: the process includes two stages, namely, the replacement stage and the heating stage. The replacement stage is used to replace the oxygen-containing air in the dust collector; the heating stage is used to preheat the dust collector in a low-oxygen environment;

[0030] During the replacement stage, the first shut-off valve 7, the second shut-off valve 8, the fifth shut-off valve 15 and the first relief valve 17 are closed, the third shut-off valve 11, the fourth shut-off valve 13 and the second relief valve 19 are opened, and the circulating fan 4 is started. At this time, the replacement medium without oxygen or with low oxygen content enters the dust collector 1 through the replacement medium inlet pipe 9 and the first circulation pipe 10, mixes with the oxygen-containing air in the dust collector 1, and then is discharged through the second circulation pipe 12 and the second relief pipe 18. The replacement medium without oxygen or with low oxygen content can be nitrogen, carbon dioxide, or hot flue gas with an oxygen content of less than 1.5%, the purpose of which is to reduce the oxygen content of the air in the dust collector. The oxygen content in the dust collector is preferably controlled between 0.6% and 1%.

[0031] When the oxygen content in the mixed gas is lower than 1.5%, the temperature rise stage is entered, the first relief valve 17 is opened, the third shut-off valve 11, the second relief valve 19 and the circulating fan 4 are closed, the delivery of the replacement medium without oxygen or with low oxygen content is stopped, and the combustible gas is introduced into the hot blast furnace at the same time. The blower is turned on, the air-fuel ratio is ignited and adjusted, and then the replacement medium without oxygen or with low oxygen content is introduced into the hot blast furnace to cool the flue gas until the flue gas temperature of the hot blast furnace is 80°C and the oxygen content is less than 1.5%. In this process, the air entering the hot blast furnace is fully burned by adjusting the air-fuel ratio of the hot blast furnace, and the flue gas generated after combustion is mixed with the replacement medium. The temperature of the mixed gas is controlled by controlling the amount of replacement medium introduced until the flue gas temperature reaches 80°C and the oxygen content is less than 1.5%.

[0032] Then open the third shut-off valve 11 and the fifth shut-off valve 15, start the circulating fan 4, and gradually close the first relief valve 17, so that the hot flue gas preheats the dust collector to form a circulation loop; thereafter, adjust the power of the hot blast furnace every hour, so that the temperature of the hot flue gas at the outlet of the hot blast furnace is increased at a heating rate of 50-100°C / h, and at the same time control the oxygen content to be less than 1.5%, and the excess hot flue gas is discharged from the second relief valve 19;

[0033] When the temperature reaches the end temperature, stop preheating, quickly turn off the circulating fan, blower, third shut-off valve and fourth shut-off valve, stop delivering oxygen-free or low-oxygen replacement medium and combustible gas, then open the first shut-off valve and the second shut-off valve to enter the normal filtration stage. The end temperature of the heating stage can be set to 300-700℃ as needed.

[0034] Embodiment 2

[0035] like Figure 2 As shown, the number of dust collectors 1 is two or more, and multiple dust collectors are arranged in parallel, and the dust-containing gas inlet pipe and the clean gas outlet pipe of the dust collector are connected to the first circulation pipe and the second circulation pipe through pipelines, and the pipeline is provided with a cut-off valve. The rest is the same as the first embodiment.

[0036] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims

1. A preheating process for a preheating device of a high-temperature, oily and dusty combustible gas dust collector, comprising a preheating device, the preheating device comprising a dust collector, a hot blast furnace, a blower and a circulating fan, the air inlet end of the dust collector is provided with a dust-containing gas inlet pipe, the air outlet end is provided with a clean gas outlet pipe, the dust-containing gas inlet pipe and the clean gas outlet pipe are respectively provided with a first shut-off valve and a second shut-off valve, the smoke chamber of the hot blast furnace is connected with a replacement medium inlet pipe, the smoke outlet of the hot blast furnace is connected with a first circulating pipe, the first circulating pipe is connected with the dust-containing gas inlet pipe, and the connection point is located at the rear of the outlet of the first shut-off valve, the first circulating pipe is installed with a third shut-off valve, and the circulating fan The air inlet of the machine is connected to a second circulation pipe, the second circulation pipe is connected to the clean air outlet pipe, and the connection point is located at the front end of the inlet of the second cut-off valve, the second circulation pipe is installed with a fourth cut-off valve, the air outlet of the circulation fan is connected to the smoke chamber of the hot blast furnace through a third circulation pipe, the third circulation pipe is installed with a fifth cut-off valve, the first circulation pipe is also connected to a first vent pipe, and the connection point is located at the front end of the inlet of the third cut-off valve, the first vent pipe is installed with a first vent valve, the third circulation pipe is also connected to a second vent pipe, and the connection point is located at the front end of the inlet of the fifth cut-off valve, the second vent pipe is installed with a second vent valve, the characteristics are: The process includes two stages, namely, a replacement stage and a heating stage. The replacement stage is used to replace the oxygen-containing air in the dust collector; the heating stage is used to preheat the dust collector in a low-oxygen environment. In the replacement stage, the first shut-off valve, the second shut-off valve, the fifth shut-off valve and the first relief valve are closed, the third shut-off valve, the fourth shut-off valve and the second relief valve are opened, and the circulating fan is started. At this time, the replacement medium with no oxygen or low oxygen content enters the dust collector through the replacement medium inlet pipe and the first circulation pipe, mixes with the oxygen-containing air in the dust collector, and then is discharged through the second circulation pipe and the second relief pipe; When the oxygen content in the mixed gas is lower than 1.5%, the replacement stage ends and the temperature rise stage begins. The first relief valve is opened, the third shut-off valve, the second relief valve and the circulating fan are closed, the delivery of the replacement medium without oxygen or with low oxygen content is stopped, and at the same time, combustible gas is introduced into the hot blast furnace. The blower is turned on, ignition is started and the air-fuel ratio is adjusted. Then, the replacement medium without oxygen or with low oxygen content is introduced into the hot blast furnace to cool down the flue gas until the flue gas temperature of the hot blast furnace is 80°C and the oxygen content is less than 1.5%. Then open the third shut-off valve and the fifth shut-off valve, start the circulating fan, and gradually close the first relief valve to allow the hot flue gas to preheat the dust collector to form a circulation loop; adjust the hot blast furnace power every hour to increase the temperature of the hot flue gas at the hot blast furnace outlet at a heating rate of 50-100°C / h, and at the same time control the oxygen content to be less than 1.5%, and the excess hot flue gas is discharged from the second relief valve; When the temperature reaches the end temperature, stop preheating, quickly close the circulating fan, blower, the third shut-off valve and the fourth shut-off valve, stop delivering the replacement medium and combustible gas with no oxygen or low oxygen content, then open the first shut-off valve and the second shut-off valve to enter the normal filtration stage.

2. The preheating process of the preheating device for a high-temperature, oily and dusty combustible gas dust collector according to claim 1 is characterized in that: The oxygen-free or low-oxygen replacement medium is nitrogen, carbon dioxide, or hot flue gas with an oxygen content of less than 1.5%.

3. The preheating process of the preheating device for a high-temperature, oily and dusty combustible gas dust collector according to claim 1 is characterized in that: The terminal temperature of the heating stage is 300-700°C.

4. The preheating process of the preheating device for a high-temperature, oily and dusty combustible gas dust collector according to claim 1 is characterized in that: The oxygen content in the dust collector is controlled between 0.6% and 1%.

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