Polyaluminum chloride mvr drum drying system
By recycling and reusing the high-temperature waste gas and condensate during the drying process of polyaluminum chloride solution, the amount of live steam used is reduced, solving the problems of dust pollution and high energy consumption, and achieving cost reduction and efficiency improvement.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- ZHENGZHOU BODA CONCENTRATION & DRYING EQUIP CO LTD
- Filing Date
- 2025-06-09
- Publication Date
- 2026-06-02
AI Technical Summary
In the existing technology, the production process of polyaluminum chloride has problems of dust pollution and high energy consumption, resulting in high cost of granular products and market supply falling short of demand.
By recovering the high-temperature waste gas and condensate evaporated during the drying process of polyaluminum chloride solution, the recovered high-temperature waste gas is used to heat the condensate to generate saturated steam, which is then pressurized and heated by a mechanical steam compressor and sent back to the drum dryer, thus realizing the reuse of heat and condensate and reducing the amount of live steam used.
It effectively reduces the production cost of solid polyaluminum chloride, improves drying efficiency and production efficiency, and avoids dust pollution and environmental pollution.
Smart Images
Figure CN224307823U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the technical field of polyaluminum chloride production equipment, specifically to a polyaluminum chloride MVR drum drying system. Background Technology
[0002] Polyaluminum chloride (PAC) is a novel water purification material, an inorganic polymeric coagulant, also known simply as polyaluminum chloride. It exhibits high charge neutralization and bridging effects on colloids and particulate matter in water, and can powerfully remove trace toxic substances and heavy metal ions, while maintaining stable properties. Due to the bridging effect of hydroxide ions and the polymerization effect of polyvalent anions, the produced PAC is an inorganic polymeric water treatment agent with a relatively large molecular weight and high charge. It can be available in both solid and liquid forms. Solid PAC is further classified by color into brownish-yellow, beige, golden yellow, and white, while liquid PAC can range from colorless and transparent, slightly yellow, light yellow to yellowish-brown. Different colors of PAC also have significant differences in application and production technology.
[0003] Solid polyaluminum chloride (PAC) is mainly produced by drying liquid PAC solution through a drum drying system or a spray drying system. Spray drying produces solid PAC in powder form, while drum drying produces it in granular form. Powdered PAC is prone to dust pollution during use. With increasing environmental awareness, dust removal equipment is necessary to reduce dust pollution. However, investing in dust removal equipment inevitably increases the cost of using PAC. Furthermore, the dust generated by the dust removal equipment is collected, resulting in raw material waste and further increasing the cost. Granular PAC, on the other hand, does not produce dust pollution during use. Therefore, the market demand for granular PAC currently exceeds supply, and prices remain high.
[0004] Granular polyaluminum chloride (PAC) is primarily produced by a drum dryer system. A PAC solution with a concentration of approximately 40% is directly fed into the drum dryer to remove moisture. The drum dryer uses steam to heat the drum, causing the PAC solution to form a thin film on its surface. This film is dried during drum rotation. A scraper then removes the solid PAC from the drum surface, completing the drying process. Heating the drum requires a large amount of heat, resulting in high steam consumption and thus high production costs for granular PAC. This is one reason why the price of granular PAC remains high in the market. Therefore, how to reduce the production cost of solid PAC while avoiding dust pollution has become a pressing technical challenge for its production. Utility Model Content
[0005] In summary, to overcome the shortcomings of existing technologies, this utility model provides a polyaluminum chloride MVR drum drying system. It recovers the high-temperature waste gas and condensate evaporated during the drying process of the polyaluminum chloride solution, uses the recovered high-temperature waste gas to heat the condensate, causing the condensate to regenerate saturated steam. The saturated steam is then compressed and heated by a mechanical steam compressor before being reintroduced into the drum dryer. This achieves the recovery and reuse of heat and condensate from the waste gas. After the system stabilizes, the live steam is only used as supplementary gas, effectively reducing the amount of live steam used and lowering the production cost of solid polyaluminum chloride.
[0006] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows:
[0007] A polyaluminum chloride MVR drum dryer system includes: a drum dryer for drying polyaluminum chloride solution; the feed inlet of the drum dryer is connected to a material pipeline for conveying the polyaluminum chloride solution; the air inlet of the drum dryer is connected to an air inlet pipeline for conveying compressed steam; a steam source is connected to the air inlet pipeline via a steam pipeline; the exhaust outlet of the drum dryer is connected to an exhaust gas pipeline for recovering high-temperature exhaust gas; the condensate outlet of the drum dryer is connected to the inlet of a condensate tank for recovering condensate; and the outlet of the condensate tank is connected to the inlet of a condensate pump.
[0008] The exhaust gas pipeline connects the exhaust gas outlet of the drum dryer to the shell-side inlet of the tube heat exchanger. The tube heat exchanger uses high-temperature exhaust gas to heat the condensate and generate pure saturated steam. The shell-side outlet of the tube heat exchanger is connected to the inlet of the vacuum pump, which vents the air. The tube-side outlet of the tube heat exchanger is connected to the inlet of the circulating pump, and the outlet of the circulating pump is connected to the tube-side inlet of the tube heat exchanger. The tube-side outlet of the tube heat exchanger is connected to the inlet of the separator, and the outlet of the separator is connected to the inlet of the steam compressor. The outlet of the separator is connected to the inlet of the circulating pump. The outlet of the condensate pump is connected to the inlet of the circulating pump. The tube-side condensate outlet of the tube heat exchanger is connected to a sewage pipe for transporting wastewater.
[0009] The outlet of the steam compressor is connected to the inlet pipe, and the gas supply port of the steam compressor is connected to the steam pipe.
[0010] Furthermore, there are multiple rotary drum dryers arranged in parallel. The air inlets of the multiple rotary drum dryers are connected to the air inlet pipeline through gas distribution branch pipes, and the gas distribution branch pipes are equipped with air inlet valves. The feed inlets of the multiple rotary drum dryers are connected to the material pipeline through material distribution branch pipes, and the material distribution branch pipes are equipped with feed valves. The exhaust gas outlets of the multiple rotary drum dryers are all connected to the exhaust gas pipeline. The condensate water outlets of the multiple rotary drum dryers are connected to the condensate water tank through condensate water branch pipes, and the condensate water branch pipes are equipped with drain valves.
[0011] Furthermore, there are multiple steam compressors connected in series, and the air supply ports of the multiple steam compressors are connected to the steam pipeline through air supply pipelines, and the air supply pipelines are equipped with air supply valves.
[0012] Furthermore, an inlet valve is provided on the pipeline connecting the outlet of the condensate pump and the inlet of the circulating pump. A level gauge for detecting the liquid level in the tube side is provided on the shell and tube heat exchanger. The level gauge is electrically connected to the inlet valve, and the inlet valve is adjusted by controlling the liquid level of the shell and tube heat exchanger.
[0013] Furthermore, the condensate tank has an outlet, which is connected to the shell-side inlet of the tube heat exchanger via a pipeline.
[0014] The beneficial effects of this utility model are as follows:
[0015] 1. This utility model recovers the high-temperature waste gas and condensate evaporated during the drying process of polyaluminum chloride solution. The recovered high-temperature waste gas is used to heat the condensate, causing the condensate to generate pure saturated steam again. The saturated steam is then compressed by a mechanical steam compressor to increase its pressure and temperature before being sent back to the drum dryer to dry the polyaluminum chloride solution. This achieves the recovery and reuse of heat from the high-temperature waste gas and condensate generated during the drying process of polyaluminum chloride solution. After the system is running stably, the live steam is only used as a supplementary gas, which can effectively reduce the amount of live steam used and reduce the production cost of solid polyaluminum chloride.
[0016] 2. This utility model has multiple drum dryers connected in parallel. Through valve control, multiple drum dryers can be used simultaneously or individually, which can effectively improve the drying speed of polyaluminum chloride solution, increase production efficiency, and increase the output of solid polyaluminum chloride.
[0017] 3. The present invention uses multiple steam compressors connected in series. By connecting multiple steam compressors in series, the saturated steam can be raised to a higher temperature, thereby increasing the temperature of the saturated steam entering the drum dryer and improving the drying efficiency of the polyaluminum chloride solution.
[0018] 4. This utility model has a simple structure, is easy to use, has a novel design, and is low in cost. It can effectively improve the drying efficiency of polyaluminum chloride solution, reduce the amount of steam used during the drying of polyaluminum chloride solution, reduce energy consumption, reduce the production cost of solid polyaluminum chloride, reduce the burden on enterprises, and at the same time avoid environmental pollution caused by the emission of high-temperature exhaust gas into the atmosphere. Attached Figure Description
[0019] Figure 1 This is a schematic diagram of the structure of this utility model. Detailed Implementation
[0020] The present invention will now be described in further detail with reference to the accompanying drawings.
[0021] like Figure 1 As shown, a polyaluminum chloride MVR drum drying system includes three drum dryers, a condensate tank 11, a condensate pump 26, a shell-and-tube heat exchanger 27, a separator 30, a vacuum pump 28, a circulation pump 29, and two steam compressors. The three drum dryers are arranged in parallel as a first drum dryer 1, a second drum dryer 2, and a third drum dryer 3. The two steam compressors are connected in series as a first steam compressor 31 and a second steam compressor 32.
[0022] The feed inlet of the first drum dryer 1 is connected to the material pipeline 5 for conveying polyaluminum chloride solution through the first distribution branch 4. The first distribution branch 4 is equipped with a first feed valve 6. The air inlet of the first drum dryer 1 is connected to the air inlet pipeline 8 through the first air distribution branch pipe 7. The first air distribution branch pipe 7 is equipped with a first air inlet valve 9. The condensate outlet of the first drum dryer 1 is connected to the water inlet of the condensate tank 11 through the first condensate branch pipe 10. The first condensate branch pipe 10 is equipped with a first drain valve 12. The feed inlet of the second drum dryer 2 is connected to the material pipeline 5 for conveying polyaluminum chloride solution through the second distribution branch 13. A second feed valve 14 is installed on the second distribution branch 13. The air inlet of the second drum dryer 2 is connected to the air inlet pipeline 8 through the second air distribution branch 15. A second air inlet valve 16 is installed on the second air distribution branch 15. The condensate outlet of the second drum dryer 2 is connected to the water inlet of the condensate tank 11 through the second condensate branch 17. A second drain valve 18 is installed on the second condensate branch 17. The feed inlet of the third drum dryer 3 is connected to the material pipeline 5 for conveying polyaluminum chloride solution via the third distribution branch 19. A third feed valve 20 is installed on the third distribution branch 19. The air inlet of the third drum dryer 3 is connected to the air inlet pipeline 8 via the third air distribution branch 21. A third air inlet valve 22 is installed on the third air distribution branch 21. The condensate outlet of the third drum dryer 3 is connected to the inlet of the condensate tank 11 via the third condensate branch 23. A third drain valve 24 is installed on the third condensate branch 23. The exhaust gas outlets of all three drum dryers are connected to the exhaust gas pipeline 25. The air inlet pipeline 8 is used to convey compressed steam, the exhaust gas pipeline 25 is used to recover high-temperature exhaust gas, and the outlet of the condensate tank 11 is connected to the inlet of the condensate pump 26.
[0023] The exhaust gas pipeline 25 is connected to the shell-side inlet of the tube heat exchanger 27. The tube heat exchanger 27 uses high-temperature exhaust gas to heat the condensate and generate pure saturated steam. The shell-side outlet of the tube heat exchanger 27 is connected to the inlet of the vacuum pump 28, and the outlet of the vacuum pump 28 vents the air. The tube-side outlet of the tube heat exchanger 27 is connected to the inlet of the circulating pump 29, and the outlet of the circulating pump 29 is connected to the tube-side inlet of the tube heat exchanger 27. The tube-side outlet of the tube heat exchanger 27 is connected to the inlet of the separator 30, and the outlet of the separator 30 is connected to the first steam compressor 31. The air inlet of the separator 30 is connected to the water inlet of the circulating pump 29, and the water outlet of the condensate pump 26 is connected to the water inlet of the circulating pump 29. A water inlet valve 38 is provided on the pipeline connecting the water outlet of the condensate pump 26 and the water inlet of the circulating pump 29. A level gauge 39 for detecting the tube-side liquid level is provided on the tube-side heat exchanger 27. The level gauge 39 is electrically connected to the water inlet valve 38, and the water inlet valve 38 is adjusted by controlling the liquid level of the tube-side heat exchanger 27. The tube-side condensate outlet of the tube-side heat exchanger 27 is connected to a sewage pipe 40 for conveying wastewater. The condensate tank 11 has an air outlet, which is connected to the shell-side air inlet of the tube-side heat exchanger 27 via a pipeline.
[0024] The outlet of the first steam compressor 31 is connected to the inlet of the second steam compressor 32. The outlet of the second steam compressor 32 is connected to the inlet pipe 8. The air supply port of the first steam compressor 31 is connected to the steam pipe 34 through the first air supply pipe 33. The first air supply pipe 33 is equipped with a first air supply valve 35. The air supply port of the second steam compressor 32 is connected to the steam pipe 34 through the second air supply pipe 36. The second air supply pipe 36 is equipped with a second air supply valve 37.
[0025] The following uses the first drum dryer 1 as an example to illustrate the usage process of this utility model.
[0026] During initial operation, the polyaluminum chloride solution is evaporated and concentrated using live steam supplied by a steam source as a heat source. The first feed valve 6 and the steam valve on steam pipeline 34 are opened, and the first drum dryer 1 is started. The polyaluminum chloride solution enters the first drum dryer 1 via material pipeline 5 and then via the first distribution branch pipe. The live steam supplied by the steam source enters the air inlet pipeline 8 via steam pipeline 34, and then enters the first drum dryer 1 via air inlet pipeline 8. Inside the first drum dryer 1, the live steam heats the drums of the first drum dryer 1 to dry the polyaluminum chloride solution. The water in the polyaluminum chloride solution evaporates, and the solid polyaluminum chloride adhering to the drum surface is detached from the drum surface by a scraper, and then output via a conveyor auger. The evaporated water becomes steam. Since this steam is generated from the polyaluminum chloride solution, it is not pure and is high-temperature exhaust gas. The vacuum pump 28 is started, and under the action of the vacuum pump 28, the high-temperature exhaust gas flows out from the exhaust gas outlet of the first drum dryer 1, and then enters the shell side of the tube heat exchanger 27 via exhaust gas pipeline 25.
[0027] The live steam entering the first drum dryer 1 is cooled and condensed into water. The first drain valve 12 is opened, and the condensate enters the condensate tank 11 through the first condensate branch. The condensate pump 26 and the circulation pump 29 are started. Under the action of the condensate pump 26 and the circulation pump 29, the condensate in the condensate tank 11 enters the shell and tube heat exchanger 27 from the upper end of the shell and tube heat exchanger 27 and flows from top to bottom along the tube side. It exchanges heat with the high-temperature exhaust gas in the shell side of the shell and tube heat exchanger 27. The condensate is heated and evaporates to produce pure saturated steam. The high-temperature exhaust gas is cooled and condensed into water. Since the high-temperature exhaust gas contains polyaluminum chloride, the condensate formed by the high-temperature exhaust gas also contains polyaluminum chloride. This condensate is discharged along the drain pipe. Since the polyaluminum chloride content is extremely low, it can be treated as wastewater. The pure saturated steam in the tube enters the separator 30 through the tube outlet. In the separator 30, some water carried by the saturated steam is separated from the saturated steam. The water re-enters the circulation heating from the water outlet of the separator 30. The separated saturated steam is discharged from the outlet at the top of the separator 30 and enters the first steam compressor 31. After being compressed and heated by the first steam compressor 31, it enters the second steam compressor 32 and is compressed and heated again before entering the inlet pipe 8. It then re-enters the first drum dryer 1 along the inlet pipe 8 for drying the polyaluminum chloride solution.
[0028] As the system operates, the high-temperature exhaust gas produced by the first drum dryer 1 increases, and the saturated steam produced by the tube heat exchanger 27 also increases. Once the system is running stably, the drying requirements of the first drum dryer 1 can be met using only saturated steam. At this point, the steam valve can be closed, and the first air supply valve 35 and the second air supply valve 37 can be opened. The live steam from the steam source can be used as supplementary gas, which can effectively reduce the amount of live steam used and reduce costs.
[0029] Similarly, the operation of the second drum dryer 2 and the third drum dryer 3 is the same as that of the first drum dryer 1. This utility model can use three drum dryers to work simultaneously to dry the polyaluminum chloride solution as needed, or any one of the three drum dryers can be used to dry the polyaluminum chloride solution, or any two of the three drum dryers can be used to dry the polyaluminum chloride solution, simply by activating the corresponding valves.
[0030] It should be noted that the above-described embodiments are illustrative of the technical solution of this utility model and not limiting. Equivalent substitutions or other modifications made by those skilled in the art based on the prior art, as long as they do not exceed the concept and scope of the technical solution of this utility model, should be included within the scope of the claims of this utility model.
Claims
1. A polyaluminum chloride MVR drum drying system, characterized in that: The equipment includes a drum dryer. The feed inlet of the drum dryer is connected to a material pipeline (5) for conveying polyaluminum chloride solution. The air inlet of the drum dryer is connected to an air inlet pipeline (8) for conveying compressed steam. The steam source is connected to the air inlet pipeline (8) via a steam pipeline (34). The exhaust outlet of the drum dryer is connected to an exhaust gas pipeline (25) for recovering high-temperature exhaust gas. The condensate outlet of the drum dryer is connected to the inlet of a condensate tank (11) for recovering condensate. The outlet of the condensate tank (11) is connected to the inlet of a condensate pump (26). The exhaust gas pipeline (25) connects the exhaust gas outlet of the drum dryer to the shell-side inlet of the tube heat exchanger (27). The tube heat exchanger (27) uses high-temperature exhaust gas to heat the condensate and generate pure saturated steam. The shell-side outlet of the tube heat exchanger (27) is connected to the inlet of the vacuum pump (28), and the outlet of the vacuum pump (28) is used for venting. The tube-side outlet of the tube heat exchanger (27) is connected to the inlet of the circulating pump (29), and the outlet of the circulating pump (29) is connected to the tube side outlet of the tube heat exchanger (27). The tube-side inlet of the tube heat exchanger (27) is connected to the air inlet of the separator (30), the air outlet of the separator (30) is connected to the air inlet of the steam compressor, the outlet of the separator (30) is connected to the inlet of the circulating pump (29), the outlet of the condensate pump (26) is connected to the inlet of the circulating pump (29), and the tube-side condensate outlet of the tube heat exchanger (27) is connected to the sewage pipe (40) for transporting sewage. The outlet of the steam compressor is connected to the inlet pipe (8), and the gas supply port of the steam compressor is connected to the steam pipe (34).
2. The polyaluminum chloride MVR drum drying system according to claim 1, characterized in that: The number of drum dryers is multiple, and the multiple drum dryers are arranged in parallel. The air inlets of the multiple drum dryers are connected to the air inlet pipeline (8) through the air distribution branch pipe. The air distribution branch pipe is equipped with an air inlet valve. The feed inlets of the multiple drum dryers are connected to the material pipeline (5) through the material distribution branch pipe. The material distribution branch pipe is equipped with a feed valve. The exhaust gas outlets of the multiple drum dryers are all connected to the exhaust gas pipeline (25). The condensate outlets of the multiple drum dryers are connected to the condensate tank (11) through the condensate branch pipe. The condensate branch pipe is equipped with a drain valve.
3. The polyaluminum chloride MVR drum drying system according to claim 1 or 2, characterized in that: The number of steam compressors is multiple, and the multiple steam compressors are connected in series. The air supply ports of the multiple steam compressors are respectively connected to the steam pipeline (34) through the air supply pipeline. The air supply pipeline is equipped with an air supply valve.
4. The polyaluminum chloride MVR drum drying system according to claim 1, characterized in that: An inlet valve (38) is provided on the pipeline connecting the outlet of the condensate pump (26) and the inlet of the circulating pump (29). A level gauge (39) for detecting the liquid level in the tube side is provided on the shell and tube heat exchanger (27). The level gauge (39) is electrically connected to the inlet valve (38), and the inlet valve (38) is adjusted by controlling the liquid level of the shell and tube heat exchanger (27).
5. The polyaluminum chloride MVR drum drying system according to claim 1, characterized in that: The condensate tank (11) has an air outlet, which is connected to the shell-side air inlet of the tube heat exchanger (27) via a pipeline.