Biomass drying exhaust gas purification system
By constructing a biomass drying exhaust gas purification system, and utilizing a wet dust collector, plasma purifier, and absorption tower, the problems of dust content and odor in biomass drying exhaust gas were solved, achieving compliant emissions of exhaust gas and recycling of wastewater.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- HUAXIN CEMENT CO LTD
- Filing Date
- 2025-06-13
- Publication Date
- 2026-06-26
AI Technical Summary
The exhaust gas from biomass drying contains a high level of dust and odor, making it impossible to directly meet emission standards. Existing technologies have failed to effectively solve the problems of dust and odor removal.
A biomass drying exhaust gas purification system is constructed, including a wet scrubber, a plasma purifier, and an absorption tower. Through multi-stage dust removal, cooling, absorption, and circulating water treatment, the exhaust gas is made compliant with emission standards.
It effectively removes dust and odor components from exhaust gas, ensuring emissions meet standards, reducing treatment costs, and enabling wastewater recycling.
Smart Images
Figure CN224404818U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of waste gas purification technology, and more specifically, to a biomass drying waste gas purification system. Background Technology
[0002] Biomass, with its advantages of being renewable, abundant, widely distributed, and possessing a certain calorific value, has become an important source of alternative fuels. However, most biomass raw materials have high moisture content, making them unsuitable for direct use as alternative fuels. Currently, the common practice is to utilize waste heat from boilers or industrial kilns for drying. Due to the variety, source, and storage and transportation of biomass raw materials, the drying exhaust gas has high dust and moisture content, and a strong odor. Direct discharge cannot meet emission limits. Therefore, dust removal and odor removal treatment of biomass drying exhaust gas is necessary before discharge.
[0003] Chinese patent CN109173444A discloses a biomass dryer exhaust gas treatment system, characterized by an exhaust pipe connected to a multi-stage cyclone dust collector, where the drying exhaust gas is directly discharged after dust removal, without considering the treatment of biomass drying odors. Chinese patent CN116123880A discloses a system and method for coupling alternative fuel drying with a cement kiln, characterized by cooling and condensing the drying exhaust gas, discharging the condensate from the system, and then connecting the dehumidified gas to the air inlet of the low-temperature section fan in the middle and rear part of a grate cooler, or simultaneously connecting it to both the air inlet of the low-temperature section fan in the middle and rear part and the air inlet of the high-temperature section fan in the front part. This method is not suitable for biomass drying processes alone. Chinese patent CN21768636U discloses a deep purification device for wood chip drying exhaust gas. Its characteristic is that after forced fixation and recovery of the drying exhaust gas, the wood chips are decomposed into solid drying material and water vapor. The dried wood chips are centrally processed, and the steam is treated into water for recycling. The treated exhaust gas undergoes secondary deep purification by an exhaust gas purification mechanism. The purified gas meets the standards and is discharged from the device. However, it does not describe the dust removal and odor removal processes for the exhaust gas. Therefore, how to provide a process for achieving compliant emissions of biomass drying exhaust gas is a problem that researchers in this field urgently need to solve. Summary of the Invention
[0004] The technical problem to be solved by this utility model is to provide a biomass drying waste gas purification system, which can effectively solve the problem of biomass drying waste gas meeting emission standards.
[0005] The technical solution adopted by this utility model to solve its technical problem is as follows: a biomass drying waste gas purification system is constructed, including a wet dust collector, a plasma purifier, an absorption tower, and a circulating water treatment device; the air inlet of the wet dust collector is connected to the waste gas pipeline, the air outlet at the top of the wet dust collector is connected to the air inlet of the plasma purifier through a pipeline, the air outlet of the plasma purifier is connected to the air inlet of the absorption tower through a pipeline, the air outlet of the absorption tower is connected to the induced draft fan through a pipeline, the drain outlet of the wet dust collector is connected to the water inlet of the circulating water treatment device through a pipeline, the water outlet of the circulating water treatment device is connected to the water pump through a pipeline, and the water pump outlet is connected to the spray assembly inside the wet dust collector through a pipeline.
[0006] According to the above scheme, the wet dust removal tower includes a tower body, with an air inlet on one side of the lower part of the tower body and an air outlet at the top of the tower body; the tower body is arranged from bottom to top as follows: a first-stage swirl plate, a first-stage spray assembly, a second-stage swirl plate, a second-stage spray assembly, a packing layer, a packing layer spray assembly, and a demisting layer.
[0007] According to the above scheme, the bottom of the wet dust removal tower is conical.
[0008] According to the above scheme, the bottom of the wet dust removal tower is equipped with drainage pipes and valves.
[0009] According to the above scheme, the circulating water treatment device includes a water tank, which is divided into three pools by an overflow plate. The pools are a flocculation pool, a sedimentation pool, and a clear water pool in the order of water flow. The flocculation pool is equipped with a stirrer, the sedimentation pool is equipped with inclined tube packing, and the outlet of the clear water pool is connected to a water pump through a pipe to supply water to the spray components inside the wet dust removal tower.
[0010] According to the above scheme, the plasma purifier includes a housing, and inside the housing, a wire mesh demister, an air filter, and a plasma generating module are arranged sequentially according to the gas flow direction.
[0011] According to the above scheme, an air inlet is opened on one side of the lower part of the absorption tower, and an air outlet is opened at the top. The gas distributor, primary spray packing layer, primary spray assembly, secondary spray packing layer, secondary spray assembly and demisting layer are arranged sequentially from bottom to top inside the absorption tower.
[0012] According to the above scheme, the bottom side of the absorption tower is connected to the washing liquid circulation tank through a pipeline. An electrochemical sensor is installed in the circulation tank. The circulation tank supplies water to the primary and secondary spray components inside the absorption tower through a water pump.
[0013] According to the above scheme, the absorbent added to the washing liquid circulation tank includes one or a mixture of several of the following: sodium hydroxide, dilute sulfuric acid, sodium hypochlorite, hydrogen peroxide, sodium sulfite, and plant extract.
[0014] According to the above scheme, the bottom of the flocculation tank, sedimentation tank and clear water tank are all conical structures, and a sewage outlet is installed at the bottom.
[0015] The biomass drying exhaust gas purification system of this utility model has the following beneficial effects:
[0016] This invention removes dust particles from biomass drying exhaust gas using a wet scrubbing tower, reduces the exhaust gas temperature, and removes some soluble odor pollutants. The exhaust gas then enters a plasma purifier to decompose most of the odor components. Finally, an absorption tower removes any remaining odor components, ensuring the exhaust gas meets emission standards. A circulating water treatment device treats the wastewater from the wet scrubbing tower through flocculation and sedimentation, enabling the wastewater to be recycled and reducing treatment costs. Attached Figure Description
[0017] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:
[0018] Figure 1 This is a process flow diagram of this utility model;
[0019] Figure 2 This is a schematic diagram of a wet dust collector tower;
[0020] Figure 3 This is a schematic diagram of a plasma air purifier;
[0021] Figure 4 This is a schematic diagram of the absorption tower structure;
[0022] Figure 5 This is a schematic diagram of a circulating water treatment device. Detailed Implementation
[0023] To provide a clearer understanding of the technical features, objectives, and effects of this utility model, the specific embodiments of this utility model will now be described in detail with reference to the accompanying drawings.
[0024] like Figure 1 As shown, the biomass drying exhaust gas purification system includes: a wet scrubber 1, a plasma purifier 2, an absorption tower 3, and a circulating water treatment device 4. The wet scrubber inlet 101 is connected to the exhaust gas pipeline; the wet scrubber top outlet 111 is connected to the plasma purifier inlet 21 via a pipeline; the plasma purifier outlet 25 is connected to the absorption tower inlet 301 via a pipeline; the absorption tower outlet 311 is connected to the induced draft fan via a pipeline; the wet scrubber drain outlet 113 is connected to the circulating water treatment device inlet 411 via a pipeline; the circulating water treatment device outlet 431 is connected to the water pump 114 via a pipeline; and the water pump outlet is connected to the wet scrubber spray fittings 103, 105, and 108 via a pipeline 112.
[0025] The drying exhaust gas first enters a wet scrubber, and after two stages of dust removal, it enters a plasma purifier. Finally, it is treated by an activated carbon box before being discharged through an exhaust stack. The wastewater from the wet scrubber is treated by a circulating water treatment device and then recycled.
[0026] like Figure 2 As shown, the wet scrubber includes a tower body 1, with an air inlet 101 on one side of the lower part of the tower body and an air outlet 111 at the top of the tower body. Inside the tower body, from bottom to top, are arranged a primary cyclone separator 102, a primary spray assembly 103, a secondary cyclone separator 104, a secondary spray assembly 105, a grid plate 106, packing material 107, a spray assembly 108, a grid plate 109, and demister packing material 110. The drying exhaust gas enters the tower through the air inlet. The gas flows upwards through the two cyclone separators, causing most of the coarse particles to settle. A small portion of fine dust continues to move upwards through the packing layer, while simultaneously flowing downwards along the packing layer under the influence of gravity from the washing liquid. During this counter-current flow, mass and heat transfer occur simultaneously between the exhaust gas and the washing liquid, resulting in both dust removal and cooling of the exhaust gas, as well as the absorption of odorous pollutants. The purified exhaust gas continues to rise through the demister layer, where most of the water vapor is captured to prevent droplets from entering the next treatment unit.
[0027] The bottom of the wet dust collector tower has a conical structure, and the dust collection wastewater is collected at the bottom of the tower body. A drain outlet 113 is installed at the bottom of the tower body to facilitate the discharge of wastewater into the circulating water treatment device 4.
[0028] like Figure 5 As shown, the circulating water treatment device includes a tank 4. Wastewater from the wet dust collector enters the flocculation tank 41 through the inlet 411 of the circulating water treatment device. After adding flocculant, the agitator 412 is started. Some of the sludge in the wastewater settles, and the remaining supernatant enters the sedimentation tank through the overflow baffle 413. After passing through the grid plate 423 and the inclined tube packing 421, most of the sludge is separated and settled. The clear water enters the clear water tank 43 through the overflow baffle 422. The clear water is supplied to the wet dust collector spray components by the water pump 114 through the pipeline 112. The bottom of the flocculation tank, sedimentation tank and clear water tank are all conical structures, and the bottom is equipped with sewage outlets 414, 424 and 432 to periodically discharge sludge.
[0029] like Figure 3As shown, the plasma purifier includes a housing 2. The exhaust gas treated by the wet scrubbing tower enters the housing 2 through the air inlet 21. Inside the housing 2, a wire mesh demister 22, an air filter 23, and a plasma generation module 24 are arranged in sequence according to the gas flow direction. The exhaust gas first passes through the wire mesh demister 22 to remove water droplets, and then passes through the air filter 23 to remove dust. The plasma generation module 24 generates active particles, including electrons, various ions, atoms, and free radicals, by applying external high pressure to break down the gas between the medium. These particles react with pollutants in the exhaust gas, causing the pollutant molecules to decompose in an extremely short time and undergo various subsequent reactions to achieve the purpose of degrading pollutants and removing odors from the exhaust gas.
[0030] like Figure 4 As shown, the absorption tower includes a tower body 3, with an air inlet 301 on one side of the lower part of the tower body and an air outlet 311 at the top of the tower body. Inside the tower body, from bottom to top, are arranged a gas distributor 302, a primary grid plate 303, a primary spray packing 304, a primary spray assembly 305, a secondary grid plate 306, a secondary spray packing layer 307, a secondary spray assembly 308, a demister grid plate 309, and a demister packing 310. Exhaust gas enters the tower through the air inlet 301 and flows upwards through the two stages of spray packing. The spray packing has a large specific surface area, significantly increasing the effective gas-liquid contact area, resulting in high mass transfer efficiency and high pollutant removal efficiency. The demister packing can remove 99% of droplets larger than 10μm.
[0031] The absorption tower includes a washing liquid circulating water tank 313. One side of the bottom of the absorption tower is connected to the washing liquid circulating water tank 313 via a pipe 314. An electrochemical sensor 315 is installed inside the circulating water tank to monitor the chemical parameters of the circulating water in real time. A level gauge 318 is installed outside the circulating water tank to monitor the liquid levels in the absorption tower and the circulating water tank in real time. A water pump 316 is installed in the circulating water tank to supply water to the absorption tower spray components 305 and 308 via a pipe 317. An absorbent dosing device is installed outside the circulating water tank to replenish the absorbent required by the absorption tower in a timely manner.
[0032] The addition of absorbent is controlled by the system control cabinet based on the monitoring data of the chemical sensor 315 in the circulating water tank and according to the set chemical index parameter range. The metering pump 321 is automatically controlled to start / stop, and the agent is added to the circulating water tank through the pipeline 322 to ensure that the chemical index of the washing liquid is within the set range, thereby maintaining the optimal absorption efficiency of the absorption tower.
[0033] The absorbent added to the washing liquid circulating water tank is a mixture of sodium hydroxide and sodium hypochlorite. The pH of the circulating water in the tank is controlled at 9-10, and the ORP is controlled at 500-600. Sodium hydroxide can absorb acidic gases in the exhaust gas, and sodium hypochlorite can deeply oxidize the odor pollutants in the exhaust gas, thereby achieving the purification effect of the exhaust gas.
[0034] According to testing, after treatment by the biomass drying exhaust gas purification system, the particulate matter content was <10 mg / m³, as determined by GB / T16157-1996. 3 According to GB 14554-93, the odor concentration of the exhaust gas is <100.
[0035] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.
Claims
1. A biomass drying waste gas purification system, characterized in that, The system includes a wet scrubbing tower, a plasma purifier, an absorption tower, and a circulating water treatment device. The air inlet of the wet scrubbing tower is connected to an exhaust gas pipeline, the air outlet at the top of the wet scrubbing tower is connected to the air inlet of the plasma purifier via a pipeline, the air outlet of the plasma purifier is connected to the air inlet of the absorption tower via a pipeline, the air outlet of the absorption tower is connected to an induced draft fan via a pipeline, the drain outlet of the wet scrubbing tower is connected to the water inlet of the circulating water treatment device via a pipeline, the water outlet of the circulating water treatment device is connected to a water pump via a pipeline, and the water pump outlet is connected to the spray assembly inside the wet scrubbing tower via a pipeline.
2. The biomass drying waste gas purification system according to claim 1, characterized in that, The wet dust collector includes a tower body with an air inlet on one side of the lower part of the tower body and an air outlet at the top of the tower body. The tower body is arranged from bottom to top as follows: a first-stage swirl plate, a first-stage spray assembly, a second-stage swirl plate, a second-stage spray assembly, a packing layer, a packing layer spray assembly, and a demisting layer.
3. The biomass drying exhaust gas purification system according to claim 1, characterized in that, The bottom of the wet dust collector is conical.
4. The biomass drying exhaust gas purification system according to claim 1, characterized in that, The bottom of the wet dust removal tower is equipped with drainage pipes and valves.
5. The biomass drying exhaust gas purification system according to claim 1, characterized in that, The circulating water treatment device includes a water tank, which is divided into three pools by an overflow plate. In order of water flow direction, the pools are a flocculation pool, a sedimentation pool, and a clear water pool. The flocculation pool is equipped with a stirrer, the sedimentation pool is filled with inclined tube packing, and the outlet of the clear water pool is connected to a water pump through a pipe to supply water to the spray components inside the wet dust removal tower.
6. The biomass drying exhaust gas purification system according to claim 1, characterized in that, The plasma purifier includes a housing, inside which a wire mesh demister, an air filter, and a plasma generating module are arranged sequentially according to the gas flow direction.
7. The biomass drying waste gas purification system according to claim 1, characterized in that, An air inlet is provided on one side of the lower part of the absorption tower, and an air outlet is provided at the top. The gas distributor, a primary spray packing layer, a primary spray assembly, a secondary spray packing layer, a secondary spray assembly, and a demisting layer are arranged sequentially from bottom to top inside the absorption tower.
8. The biomass drying waste gas purification system according to claim 7, characterized in that, The bottom side of the absorption tower is connected to the washing liquid circulation tank via a pipe. An electrochemical sensor is installed in the circulation tank. The circulation tank supplies water to the primary and secondary spray components inside the absorption tower via a water pump.
9. The biomass drying exhaust gas purification system according to claim 5, characterized in that, The bottom of the flocculation tank, sedimentation tank and clear water tank are all conical structures, and a sewage outlet is installed at the bottom.