Post-treatment waste heat recovery system for titanium dioxide product prepared by chlorination method
By adding flue gas recirculation and air heater in the production process of titanium dioxide by chlorinating the titanium dioxide, the exhaust heat at the tail gas is heated to solve the problem of unused exhaust heat at the tail gas, and efficient recovery of waste heat and reduction of fuel consumption are achieved.
Patent Information
- Application Number
- CN202422838512.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-21
- Publication Date
- 2025-07-18
- Estimated Expiration
- 2034-11-21
AI Technical Summary
During the existing chlorinated titanium dioxide production process, the waste heat of the tail flue gas is not effectively utilized, resulting in high fuel consumption.
By adding a flue gas recirculation pipe and air heater in the flue gas flow path, the exhaust heat of the tail flue gas is used to heat the combustion air, reducing the amount of natural gas combustion required, and further waste heat recovery is achieved in combination with the gas-water heat exchanger.
It effectively reduces the natural gas consumption in the flash drying process, improves the waste heat recovery effect, simplifies the engineering volume and reduces investment costs.
Smart Images
Figure CN223121894U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of titanium dioxide production equipment, in particular to a waste heat recovery system for post-treatment of titanium dioxide products prepared by the chlorination method. Background Art
[0002] In the production process of titanium dioxide prepared by the chlorination method, the produced titanium dioxide contains water and is in a mud-like state. To meet the requirements of industrial applications, it needs to be dried and ground before leaving the factory. This process is called post-treatment, and it mainly uses flash drying to directly transfer heat and mass between titanium dioxide and hot flue gas at about 400°C to remove the water in titanium dioxide. As shown in the figure, natural gas is mixed with air and burned through a burner. The temperature of the flue gas is relatively high, and a part of cold air (dilution air, not participating in combustion) needs to be inhaled from the environment to dilute the flue gas to about 400°C. The flue gas exchanges heat with titanium dioxide in the flash dryer. To enable full heat exchange of titanium dioxide, a stirring device is used to stir and break it in the flash dryer. After drying and meeting the requirements, the titanium dioxide is collected by a bag filter under the suction of an induced draft fan to obtain dried titanium dioxide, and after further grinding, the finished product is obtained; while the flue gas after filtering the product is drawn by the induced draft fan and discharged to the environment. This part of the flue gas is about 150°C and still has the value of waste heat utilization, but the existing post-treatment system has not utilized it. Content of the Utility Model
[0003] Aiming at the problems existing in the above-mentioned prior art, the utility model aims to provide a waste heat recovery system for post-treatment of titanium dioxide products prepared by the chlorination method to realize the recycling of tail flue gas.
[0004] To achieve the above purpose, the utility model provides a waste heat recovery system for post-treatment of titanium dioxide products prepared by the chlorination method, which includes a furnace and a flash dryer, a bag filter and an induced draft fan arranged in sequence along the flue gas flow direction. The burner is provided with a natural gas inlet and an ambient air inlet. A dilution air cooling jacket is arranged outside the furnace, and a dilution air inlet is provided on the dilution air cooling jacket. A burner is arranged in the combustion chamber of the furnace. The flue gas generated by the combustion of the burner is mixed with dilution air at the end of the furnace and then flows into the flash dryer. A flue gas pipeline is connected between the flue gas outlet of the flash dryer and the flue gas inlet of the bag filter, and between the flue gas outlet of the bag filter and the flue gas inlet of the induced draft fan. The flue gas outlet of the induced draft fan is connected with a flue gas discharge pipe, and a flue gas recirculation pipe branches from the flue gas discharge pipe and is connected with the dilution air inlet of the furnace.
[0005] It also includes an air heater arranged on the front side of the burner and a heat exchanger arranged on the rear side of the induced draft fan, the air heater is provided with an ambient air inlet, the air outlet of the air heater is connected to the ambient air inlet of the burner through an air duct, the end of the flue gas exhaust pipe is connected to the flue gas inlet of the heat exchanger, the smoke gas outlet of the heat exchanger is connected to a smoke exhaust pipe, the water outlet of the heat exchanger is connected to the water inlet of the heater through a water pipe, the water outlet of the heater is connected to the water inlet of the heat exchanger through a water pipe, thereby forming a heat exchange circulation water circuit, and the heat exchange circulation water circuit is equipped with a circulation pump.
[0006] That is, in the original system, an air-water heat exchanger is added after the flue gas recirculation pipe, and an air heater is added at the burner inlet. The waste heat of the hot flue gas discharged into the environment is used to heat water, and the water is pumped into the heater through a water pump to heat the air for combustion, thereby realizing further waste heat recovery, reducing fuel usage, and achieving the purpose of energy saving and consumption reduction.
[0007] In the above scheme: the heat exchange circulation water circuit is equipped with an expansion water tank, and the expansion water tank is connected to a water supply pipe to accommodate and compensate for the expansion and contraction of water in the system.
[0008] In the above scheme: the flue gas external exhaust pipe is provided with a regulating valve for regulating the flue gas flow rate entering the heat exchanger, so that the flue gas flow entering the flue gas recirculation pipe and the heat exchanger can be reasonably distributed.
[0009] In the above scheme: the furnace includes an inner wall and an outer wall, the inner wall encloses a combustion chamber, the burner extends to the front end of the combustion chamber, the outer wall is a dilution air jacket, the interlayer between the outer wall and the inner wall forms a dilution air channel, the dilution air inlet is arranged at the front end of the dilution air channel, and the end of the dilution air channel is connected to the end of the combustion chamber. Smoke is generated in the combustion chamber, and the smoke and dilution air energy are mixed in the furnace and then enter the flash dryer.
[0010] The beneficial effect of the utility model is that since the dilution air does not participate in the combustion, the oxygen content of this part of the dilution air has no effect on the combustion, and the air volume required for the natural gas combustion is all provided by the blower of the burner. Based on this feature, by adding a flue gas recirculation pipe, the hot flue gas originally discharged directly into the environment is directly introduced into the furnace for use as dilution air, and the temperature of the flue gas entering the flash dryer is adjusted by adjusting the consumption of natural gas. Most of the hot flue gas is recycled through the flue gas recirculation pipe, and part of the flue gas enters the heat exchanger for heating the ambient air entering the burner, thereby further reducing the use of methane gas.
[0011] In summary, the originally externally discharged hot flue gas is led to the furnace through a pipeline and directly mixed with the flue gas from natural gas combustion. The heat transfer is rapid, avoiding the use of a heat exchanger to heat the dilution air. The process is simple, with a small amount of engineering work and investment, and has a good waste heat recovery effect, effectively reducing the natural gas consumption in the flash drying process. BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The above and / or additional aspects and advantages of the present utility model will become apparent and be readily understood from the description of the embodiments in conjunction with the following drawings, where:
[0013] Figure 1 is the schematic diagram of the present utility model.
[0014] Figure 2 is the structural schematic diagram of the furnace. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0015] As Figure 1 shown in FIG. -2, a waste heat recovery system for the post-treatment of titanium dioxide products by the chlorination method mainly consists of a furnace 2, a flash dryer 3, a bag filter 4, and a draft fan 5 arranged in sequence along the flue gas flow direction.
[0016] A burner 1 is arranged in the combustion chamber of the furnace. A natural gas inlet and an ambient air inlet are provided on the burner 1. A dilution air cooling jacket is arranged outside the furnace 2, and a dilution air inlet is provided on the dilution air cooling jacket. The flue gas generated by the combustion of the burner 1 and the dilution air are mixed at the end of the furnace 2 and then flow into the flash dryer 3. Specifically: The furnace 2 includes an inner wall and an outer wall. The inner wall encloses the combustion chamber 21, and the burner 1 extends to the front end of the combustion chamber 21. The outer wall is a dilution air jacket, and the interlayer between the outer wall and the inner wall forms a dilution air channel 22. The dilution air inlet is arranged at the front end of the dilution air channel 22, and the end of the dilution air channel 22 is communicated with the end of the combustion chamber 21. The flue gas is generated in the combustion chamber 21, and the flue gas and the dilution air can be mixed in the furnace 2 and then enter the flash dryer 3.
[0017] A flue gas pipeline is connected between the flue gas outlet of the flash dryer 3 and the flue gas inlet of the bag filter 4, and between the flue gas outlet of the bag filter 4 and the flue gas inlet of the draft fan 5. A flue gas exhaust pipe a is connected to the flue gas outlet of the draft fan 5, and a flue gas recirculation pipe b branches from the flue gas exhaust pipe a and is connected to the dilution air inlet of the furnace 2.
[0018] A warm air heater 6 is provided at the front side of the burner 1, and a heat exchanger 7 is provided at the rear side of the induced draft fan 5. An ambient air inlet is provided on the warm air heater 6. The air outlet of the warm air heater 6 is connected to the ambient air inlet of the burner 1 through an air duct. The end of the flue gas exhaust pipe a is connected to the flue gas inlet of the heat exchanger 7, and a smoke exhaust pipe is connected to the flue gas outlet of the heat exchanger 7. The water outlet of the heat exchanger 7 is connected to the water inlet of the warm air heater 6 through a water duct, and the water outlet of the warm air heater 6 is connected to the water inlet of the heat exchanger 7 through a water duct, thereby forming a heat exchange circulating water path c. A circulation pump 10 is equipped on the heat exchange circulating water path c.
[0019] That is, in the original system, after the flue gas recirculation pipe b, a gas-water heat exchanger is added, and a warm air heater 6 is added at the inlet of the burner 1. The waste heat of the hot flue gas discharged into the environment is used to heat water, and the water is sent into the warm air heater 6 through a water pump for heating the combustion air, so as to realize further waste heat recovery, reduce the fuel consumption, and achieve the purpose of energy conservation and consumption reduction.
[0020] An expansion tank 8 is equipped on the heat exchange circulating water path c, and a make-up water pipe is connected to the expansion tank 8 to accommodate and compensate for the expansion and contraction of the water in the system.
[0021] A regulating valve 9 for adjusting the flue gas flow rate entering the interior of the heat exchanger 7 is provided on the flue gas exhaust pipe a, so as to reasonably distribute the flue gas volume entering the flue gas recirculation pipe b and the heat exchanger 7.
Claims
1. A post-treatment waste heat recovery system for titanium dioxide products by the chlorination process, comprising a furnace chamber (2), a flash dryer (3), a bag filter (4), and a induced draft fan (5) arranged in sequence along the flue gas flow direction. A burner (1) is arranged in the combustion chamber of the furnace chamber. A natural gas inlet and an ambient air inlet are arranged on the burner (1). A dilution air cooling jacket is arranged outside the furnace chamber (2), and a dilution air inlet is arranged on the dilution air cooling jacket. The flue gas generated by the combustion of the burner (1) is mixed with the dilution air at the end of the furnace chamber (2) and then flows into the flash dryer (3). A flue gas pipeline is connected between the flue gas outlet of the flash dryer (3) and the flue gas inlet of the bag filter (4), and between the flue gas outlet of the bag filter (4) and the flue gas inlet of the induced draft fan (5). The flue gas outlet of the induced draft fan (5) is connected with a flue gas discharge pipe (a). It is characterized in that: A flue gas recirculation pipe (b) branches from the flue gas discharge pipe (a) and is connected to the dilution air inlet of the furnace chamber (2); further comprising a warm air heater (6) arranged on the front side of the burner (1) and a heat exchanger (7) arranged on the rear side of the induced draft fan (5). An ambient air inlet is arranged on the warm air heater (6). The air outlet of the warm air heater (6) is connected to the ambient air inlet of the burner (1) through an air pipeline. The end of the flue gas discharge pipe (a) is connected to the flue gas inlet of the heat exchanger (7). The flue gas outlet of the heat exchanger (7) is connected with a smoke exhaust pipe. The water outlet of the heat exchanger (7) is connected to the water inlet of the warm air heater (6) through a water pipeline. The water outlet of the warm air heater (6) is connected to the water inlet of the heat exchanger (7) through a water pipeline, thus forming a heat exchange circulating water path (c). A circulating pump (10) is equipped on the heat exchange circulating water path (c).
2. The post-treatment waste heat recovery system for titanium dioxide products prepared by the chlorination process according to claim 1, wherein: An expansion tank (8) is equipped on the heat exchange circulating water path (c), and a make-up water pipe is connected to the expansion tank (8).
3. The post-treatment waste heat recovery system for titanium dioxide products prepared by the chlorination process according to claim 1, wherein: A regulating valve (9) for regulating the flue gas flow rate entering the heat exchanger (7) is arranged on the flue gas discharge pipe (a).
4. The post-treatment waste heat recovery system for titanium dioxide products prepared by the chlorination process according to claim 1, characterized in that: The furnace chamber (2) comprises an inner side wall and an outer side wall. The inner side wall encloses a combustion chamber (21). The burner (1) extends to the front end of the combustion chamber (21). The outer side wall is a dilution air jacket. The interlayer between the outer side wall and the inner side wall forms a dilution air channel (22). The dilution air inlet is arranged at the front end of the dilution air channel (22). The end of the dilution air channel (22) is communicated with the end of the combustion chamber (21).