Device and method for self-circulation of fluidized bed gas

Abstract

The present invention discloses a device and method for self-circulation of fluidized bed gas, and relates to fluidized bed drying equipment in the pharmaceutical industry. The device comprises a fluidized bed main unit, a mixer, a dust collector, an air inlet processor, an exhaust device, a circulating fan, an air inlet duct, an air outlet duct, an exhaust duct, a circulating air duct, an air supply duct and a control system. The device can realize self-circulation of fluidized gas in the fluidized bed, maximize the utilization of heat in the hot and humid air exhausted from the fluidized bed while meeting the operating requirements, and overcome the problems of high energy consumption, high requirements for preparation technology, and environmental risks in the prior art.

Description

Technical Field

[0001] The invention relates to fluidized bed drying equipment in the pharmaceutical industry, in particular to a device and method for self-circulation of fluidized gas based on a fluidized bed granulation and drying process. Background Art

[0002] Fluidized beds are mostly used in the pharmaceutical industry for material drying and particle preparation. Fluidized bed drying is to place wet materials in a fluidized bed silo, and allow the wet materials to be fluidized by hot dry air entering the fluidized bed. The hot dry air fully contacts the wet materials during the process of fluidizing the wet materials, and removes the moisture in the wet materials, thereby achieving the purpose of drying. The hot air that removes the moisture is discharged into the natural environment after intercepting the fine powder through the dust collector. Fluidized bed granulation is a method that concentrates the three steps of mixing, granulation and drying in the original drug preparation in a fluidized bed and completes them at one time. The process is to place the dry powder material in the fluidized bed silo, and the dry hot air entering the fluidized bed makes the dry powder material fluidized. In the fluidizing chamber, the binder solution is atomized by a spray gun to form tiny droplets and sprayed onto the fluidized dry powder material. The tiny binder droplets wet the contacted powder and agglomerate around it to form particle nuclei. At the same time, the droplets that continue to be sprayed fall on the surface of the particle nucleus to produce a bonding bridging effect, so that the particle nuclei and the particle nuclei are combined with each other, and gradually larger particles are formed. Under the action of dry hot air, the particles are dried, and the liquid bridges between the powders become solid bridges, that is, porous particles with a rounded appearance are obtained.

[0003] However, there are also many problems in the fluidized production process. For example, the fluidized drying and fluidized bed granulation process requires hot air to continuously evaporate the moisture in the wet material or adhesive solution. The entire preparation process takes a long time and uses a large amount of dry hot air, which leads to a large amount of energy consumption for preparing dry hot air. For example, the existing fluidized bed structures all use natural environment induced air, which enters the fluidized bed after being dehumidified, heated and purified by the air inlet processor. After the dry hot air participates in the fluidization of the material, it passes through the filter chamber and the dust collector to intercept the fine powder and is directly discharged to the natural environment. In the fluidized bed granulation operation, the particle preparation process has high requirements on the consistency of temperature and humidity inside the fluidized bed. Only when the indicators are the same can the reusability of the operating parameters be good and the quality of the prepared materials be uniform. However, since the air is taken from the natural environment and is affected by However, due to the influence of environmental climate change fluctuations, the fluidized bed air inlet processor needs to constantly change parameters to achieve the consistency of various indicators that meet the fluidization state of the fluidized bed. This has caused the increase of uncontrollable factors in the fluidized bed granulation process, increased control difficulty, and practical problems such as poor material quality uniformity; in addition, the existing fluidized bed hot air full emission working mode has brought great impact on environmental protection. First, high-temperature gas emissions into the environment increase the heat of the environment and cause thermal pollution. Secondly, although the exhaust gas is filtered by solid particles in the filter chamber and dust collector, there will still be a lot of fine particles entering the environment with the exhaust gas, increasing the content of PM10 and PM2.5 in the atmosphere. Thirdly, during the preparation process of the fluidized bed, volatile substances enter the atmosphere with the exhaust gas, causing environmental odor indicators to exceed the standard.

[0004] As an excellent equipment for preparing pharmaceutical particles, the fluidized bed is very necessary to give full play to the advantages of simple preparation process and continuous process while reducing energy consumption, environmental risks and operating difficulty. Summary of the invention

[0005] The purpose of the present invention is to overcome the problems of high energy consumption, high preparation technology requirements, environmental risks and the like in the prior art, and to provide a device and method for self-circulation of fluidizing gas based on a fluidized bed granulation and drying process, so as to realize self-circulation of fluidizing gas in a fluidized bed, and maximize the utilization of heat in the hot and humid air exhausted from the fluidized bed while meeting the operating requirements.

[0006] The present invention solves the technical problem by adopting the following technical solutions:

[0007] A fluidized bed gas self-circulation device comprises: a fluidized bed main unit, a mixer, a dust collector, an air inlet processor, an exhaust device, a circulating fan, an air inlet duct, an air outlet duct, an exhaust duct, a circulating air duct, an air supply duct and a control system; wherein the air inlet of the fluidized bed main unit is connected to the mixer via the air inlet duct, and the air outlet is connected to the dust collector via the air outlet duct; the air outlet of the dust collector is connected to the exhaust duct and the circulating air duct via a duct; the exhaust duct is controlled by the exhaust device, and the circulating air duct is controlled by the circulating fan; the mixer is connected to the circulating air duct via a short-circuit air duct, and is connected to the air outlet of the air inlet processor via another duct; the air inlet of the air inlet processor is connected to the circulating air duct.

[0008] Furthermore, the exhaust device is selected from one of an exhaust fan, an exhaust valve or a vacuum pump.

[0009] Furthermore, the air inlet duct is provided with a hot dry air flow rate sensor, a temperature and humidity sensor and a pressure sensor.

[0010] Furthermore, the air outlet duct is provided with a temperature and humidity sensor and a pressure sensor.

[0011] Furthermore, the circulating air duct includes a first section of the circulating air duct, a second section of the circulating air duct and a third section of the circulating air duct; the air inlet end of the first section of the circulating air duct is connected to the air outlet of the dust collector, the air inlet of the circulating fan at the air outlet end and the air inlet of the exhaust duct; the air inlet end of the second section of the circulating air duct is connected to the air outlet of the circulating fan, and the air outlet end is connected to the air inlet end of the third section of the circulating air duct, the air outlet end of the make-up air duct and the air inlet end of the short-circuit air duct; the air outlet end of the third section of the circulating air duct is connected to the air inlet end of the air intake processor; wherein a valve is arranged at the air inlet end of the first section of the circulating air duct, a valve is arranged at the air outlet end of the second section of the circulating air duct, and a valve is arranged at the air inlet end of the third section of the circulating air duct.

[0012] Furthermore, a valve is provided at the air inlet end of the exhaust duct.

[0013] Furthermore, a valve is arranged on the short-circuit air duct.

[0014] Furthermore, a valve is provided on the air supply pipe.

[0015] Furthermore, the fluidized bed main unit includes a bracket, a buffer chamber, a material bin, a fluidizing chamber and a filter chamber which are connected in sequence from bottom to top and fixed by the bracket, and a spray gun arranged on the vulcanization chamber. The buffer chamber, the material bin, the fluidizing chamber and the filter chamber are tightly connected by a sealing ring and isolated from the outside world.

[0016] Furthermore, a temperature sensor is arranged on the material bin to detect the granulation temperature during the granulation process and to detect the drying temperature during the drying process.

[0017] Furthermore, a pressure sensor is provided in the fluidizing chamber.

[0018] Furthermore, the air inlet of the buffer chamber is the air inlet of the fluidized bed main unit, and a valve is provided at the air inlet to connect to the air inlet duct.

[0019] Furthermore, the air outlet of the filter chamber is the air outlet of the fluidized bed main unit, and a valve is provided at the air outlet to connect to the air outlet duct.

[0020] Furthermore, the air inlet processor includes a gas dehumidification and heating processing device.

[0021] Furthermore, the air inlet processor includes an air inlet processor housing and a primary filter, a medium filter, a surface cooler, a steam heater and a high efficiency filter arranged in sequence from the air inlet to the air outlet inside the air inlet processor housing.

[0022] Furthermore, the air inlet processor box is provided with a chilled water inlet and outlet and a steam inlet connected to the surface cooler and the steam heater, and a condensate outlet for connecting the chilled water and steam medium outside the equipment.

[0023] Furthermore, the dust collector includes a dust collector housing and a dust filter.

[0024] A method for self-circulation of fluidized bed gas, comprising the following steps:

[0025] (1) Powdered materials are put into the material bin of the fluidized bed main machine, and the temperature and humidity required for the granulation and drying stages of the fluidized bed main machine are set according to the control system;

[0026] (2) Start the fluidized bed main unit, and the control system starts working according to the pre-programmed program. First, the surface cooler and steam heater are turned on, the valve on the air supply pipe and the valve on the exhaust pipe are opened, and the exhaust fan is turned on. The fluidized bed system enters the working state, and the powdered material inside the material bin is fluidized;

[0027] (3) The control system monitors the fluidization chamber pressure of the fluidized bed main unit. When the pressure sensor in the fluidized chamber detects that the pressure in the fluidized chamber reaches a range of -100Pa to -2000Pa, the valve on the first section of the circulating air duct, the valve on the second section of the circulating air duct, and the valve on the third section of the circulating air duct are opened, and the circulating fan is turned on. At the same time, the exhaust fan, the valve on the exhaust duct, and the valve on the supply air duct are closed, and the fluidized bed system enters a self-circulating condition;

[0028] (4) The control system monitors the flow rate, temperature, humidity and pressure of the hot dry air on the air inlet duct during the self-circulation operation, and monitors the material temperature through the temperature sensor on the material bin. When the material temperature reaches 50° C. to 80° C., granulation begins;

[0029] (5) During the fluidized granulation process, the control system detects the temperature and humidity of the inlet air according to the temperature and humidity sensor on the inlet air duct, and adjusts the valve on the short-circuit air duct and the valve on the third-section circulating air duct according to the set value, and adjusts the proportion of the hot and humid air that is not processed by changing the opening ratio of the two valves;

[0030] (6) During the fluidized granulation process, the pressure sensor in the fluidized chamber always detects the pressure in the fluidized chamber. When the pressure in the fluidized chamber exceeds the set range, the control system starts the exhaust fan and opens the valve on the exhaust duct to discharge excess gas to ensure that the system operates within the set pressure range;

[0031] (7) After the fluidized bed completes the granulation process, it enters the drying state. The proportion of the treated hot and humid air is adjusted by controlling the valve on the third-section circulating air duct and the valve on the short-circuit air duct to ensure that the treated hot and dry air meets the drying requirements.

[0032] Furthermore, in step (1), in the granulation stage, the granulation temperature of the fluidized bed is 50°C to 80°C, and the relative humidity is 5% to 20%; in the drying stage, the drying temperature of the fluidized bed is 60°C to 90°C, and the relative humidity is 2% to 15%.

[0033] Furthermore, in step (5), the proportion of the untreated hot and humid air is controlled at 0% to 40%.

[0034] Furthermore, in step (6), depending on the configuration of the binder required for granulation, the exhaust gas is 2% to 15% of the total air volume of the system.

[0035] The beneficial effects of the present invention are as follows: the self-circulation of fluidized bed gas is achieved through precise detection instruments and control systems, which greatly reduces the environmental impact and possible environmental risks caused by fluidized bed exhaust; the automatic and stable control system ensures the stability of the fluidized bed air intake conditions, avoids the impact of environmental change factors on fluidized bed production, reduces the difficulty of operation, and improves product quality; the mixer avoids the energy loss caused by the full treatment of the system's circulating air, and greatly improves energy utilization. The present invention improves production efficiency, reduces operational difficulty, and achieves the goal of reducing energy consumption and environmental risks. The present invention can promote the application scope of fluidized bed equipment and enhance the product value of fluidized bed preparation technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 The figure is a schematic diagram of a fluidized bed gas self-circulation device of the present invention.

[0037] Figure 2 It is a schematic diagram of the structure of a fluidized bed main engine of the present invention.

[0038] Figure 3 The figure is a schematic diagram of the structure of an air intake processor of the present invention.

[0039] Figure 4 A schematic diagram of the structure of a dust collector of the present invention. DETAILED DESCRIPTION

[0040] In order to make the above features and advantages of the present invention more obvious and easy to understand, embodiments are given below and described in detail with reference to the accompanying drawings.

[0041] The present invention provides an embodiment, wherein a fluidized bed gas self-circulation device and method proposed by the present invention are used for the self-circulation of gas in a fluidized bed. The fluidized bed gas self-circulation device is as follows: Figure 1 As shown, the fluidized bed main unit 110 includes: a fluidized bed main unit 110, a mixer 120, a dust collector 130, an air inlet processor 140, an exhaust device 150, a circulating fan 160, an air inlet duct 170, an air outlet duct 180, an exhaust duct 190, a circulating air duct 200, a supplementary air duct 210 and a control system 220; wherein the air inlet of the fluidized bed main unit 110 is connected to the mixer 120 through the air inlet duct 170, and the air outlet is connected to the dust collector 130 through the air outlet duct 180 The air outlet of the dust collector 130 is connected to the exhaust duct 190 and the circulating air duct 200 through a pipe; the exhaust duct 190 is controlled by the exhaust device 150, and the circulating air duct 200 is controlled by the circulating fan 160; the mixer 120 is connected to the circulating air duct 200 through a short-circuit air duct 230, and is connected to the air outlet of the air inlet processor 140 through another pipe; the air inlet of the air inlet processor 140 is connected to the circulating air duct 200.

[0042] Specifically, the fluidized bed main unit 110 is as follows: Figure 2 As shown, the main machine includes a bracket 116, a buffer chamber 111, a material bin 112, a fluidizing chamber 114 and a filter chamber 115 connected sequentially from bottom to top and fixed by the bracket 116, and a liquid spray gun 113 arranged on the vulcanization chamber. The buffer chamber 111, the material bin 112, the fluidizing chamber 114 and the filter chamber 115 are tightly connected through a sealing ring and isolated from the outside world. The air inlet of the buffer chamber 111 is the air inlet of the fluidized bed main machine 110, and a valve 241 is arranged on the air inlet, which is connected to the air inlet duct 170. A temperature sensor is arranged on the material bin 112. A pressure sensor is arranged on the fluidizing chamber 114. The air outlet of the filter chamber 115 is the air outlet of the fluidized bed main machine 110, and a valve 242 is arranged on the air outlet, which is connected to the air outlet duct 180. The air inlet duct 170 is provided with a dry hot air flow rate sensor, a temperature and humidity sensor and a pressure sensor. The air outlet duct 180 is provided with a temperature and humidity sensor and a pressure sensor.

[0043] The air intake processor 140 is as follows Figure 3As shown, the processing device for gas dehumidification and heating includes an air inlet processor housing 146 and a primary filter 141, a medium filter 142, a surface cooler 143, a steam heater 144 and a high efficiency filter 145 arranged in sequence from the air inlet to the air outlet inside the air inlet processor housing 146. The air inlet processor housing 146 is provided with a chilled water inlet and a steam inlet connected to the surface cooler 143 and the steam heater 144, and a condensed water outlet for connecting the chilled water and steam media outside the equipment.

[0044] A mixer 120 is provided between the fluidized bed main unit 110 and the air inlet processor 140 for fully mixing the gas. A valve 247 is provided on the short-circuit air pipe 230 of the mixer 120 .

[0045] Dust collector 130 Figure 4 As shown, it includes a dust collector housing 131 and a dust filter 132. The air outlet of the dust collector 130 is connected to the circulating air duct 200 and the exhaust air duct 190. The circulating air duct 200 includes a first section circulating air duct 201, a second section circulating air duct 202 and a third section circulating air duct 203. The air inlet end of the first section circulating air duct 201 is connected to the air outlet of the dust collector 130, and the air outlet end is connected to the air inlet of the circulating fan 160. The air inlet end of the second section circulating air duct 202 is connected to the air outlet of the circulating fan 160, and the air outlet end is connected to the air inlet of the circulating fan 160. The air end is connected to the air inlet end of the third section of the circulating air duct 203, the air outlet end of the supplementary air duct 210 and the air inlet end of the short-circuit air duct 230; the air outlet end of the third section of the circulating air duct 203 is connected to the air inlet end of the air inlet processor 140; wherein a valve 243 is provided at the air inlet end of the first section of the circulating air duct 201, a valve 245 is provided at the air outlet end of the second section of the circulating air duct 202, and a valve 246 is provided at the air inlet end of the third section of the circulating air duct 203. An exhaust device 150 is provided on the exhaust duct 190, which is selected from one of an exhaust fan, an exhaust valve or a vacuum pump. In this embodiment, an exhaust fan is selected. The exhaust device 150 divides the exhaust duct 190 into two sections, and its air inlet is connected to the first section of the exhaust duct 191, and its air outlet is connected to the second section of the exhaust duct 192. A valve 244 is provided at the air inlet end of the first section of the exhaust duct 191. A valve 248 is provided on the supplementary air duct 210.

[0046] The fluidized bed is a drying or granulating equipment, and its granulation process includes two processes, the granulation stage and the drying stage, and its drying function is the same as the drying stage of the granulation process. The present invention is based on the use of the air inside the fluidized bed and its components and pipelines for recycling, adjusting the humidity of the circulating air through the surface cooler 143, adjusting the air temperature through the steam heater 144, and at the same time, a part of the humid hot air that does not need to be dehumidified and heated is mixed with the heated dry hot air to become dry hot air suitable for the fluidized bed granulation or drying process and sent into the fluidized bed to complete the production process. While meeting the needs of fluidized bed drying or granulation production, the present invention reduces energy consumption, avoids or reduces fluidized bed gas emissions, and reduces environmental pollution. At the same time, the precisely controlled inlet air temperature and humidity are always under the working conditions required for production, reducing the complexity of production operations and improving the uniformity of product quality.

[0047] The operation of the fluidized bed gas self-circulation device proposed by the present invention in the fluidized bed granulation production process is as follows:

[0048] The powdered material is put into the material bin 112 of the fluidized bed, and the temperature and humidity required for the granulation and drying stages of the fluidized bed are set by the control system 220. In the granulation stage, the granulation temperature is preferably controlled at 50°C to 80°C according to different types of Chinese medicine, and the relative humidity of dry hot air is controlled at 5% to 20%. The working temperature and humidity suitable for the product are adjusted according to different products.

[0049] The fluidized bed is started, and the control system 220 starts working according to a pre-programmed program. First, the control system 220 turns on the surface cooler 143 and the steam heater 144, opens the valve 248 on the air supply duct 210 and the valve 244 on the exhaust duct 191, turns on the exhaust fan, and the fluidized bed enters the working state, and the powdered material inside the material bin 112 is fluidized; the control system 220 monitors the pressure of the fluidizing chamber 114 of the fluidized bed host 110, and after the pressure sensor of the fluidizing chamber 114 detects that the pressure of the fluidizing chamber 114 reaches the range of -100Pa to -2000Pa, the control system 220 opens the valve 243 on the first section circulating air duct 201, the valve 245 on the second section circulating air duct 202, and the valve 246 on the third section circulating air duct 203, turns on the circulating fan 160, and at the same time turns off the exhaust fan, the valve 244 on the exhaust duct 191, and the valve 248 on the air supply duct 210, and the fluidized bed system enters the self-circulating working state. The control system 220 monitors the flow rate, temperature, humidity and pressure of the hot dry air on the air inlet duct 170 during the self-circulation operation, and monitors the material temperature through the temperature sensor on the material bin 112. When the material temperature reaches 50°C to 80°C, granulation begins.

[0050] The spray gun 113 on the fluidized bed main unit 110 sprays compressed air at high speed to atomize the adhesive input into the spray gun 113 into tiny droplets and spray them onto the powdered material in the fluidized state. The tiny adhesive droplets wet the powder they come into contact with and agglomerate around them to form particle nuclei. At the same time, the droplets that continue to be sprayed fall on the surface of the particle nuclei to produce a bonding bridging effect, so that the particle nuclei and the particle nuclei and the particles are combined with each other to gradually form larger particles. Under the action of the dry hot air, the moisture in the wet particles that are bonded together is dried and taken away, and the particles become dry; in this way, the circulating particles continue to grow until the particle size requirements of the product are reached; in the granulation process, the dry hot air continuously takes away the moisture in the wet particles, so that the moisture content of the air discharged from the main machine outlet duct 180 increases and becomes humid hot air. The humid hot air intercepts the dust and particles in the air through the dust collector 130, and then enters the circulating air duct 200, and is sent to the air inlet processor 140 and the short-circuit air duct 230 by the circulating fan 160. The humid hot air entering the air inlet processor 140 passes through the surface cooler 143 inside the processor, cools the air and precipitates the moisture in the air to become dry air, and becomes dry hot air after being heated by the steam heater 144. The treated dry hot air is mixed with the humid hot air sent from the short-circuit duct in the mixer 120 and then sent to the fluidized bed main machine 110 through the air inlet duct 170, completing an air circulation process.

[0051] The control system 220 detects the temperature and humidity of the inlet air according to the temperature and humidity sensor on the inlet air duct 170, and adjusts the valve 247 on the short-circuit air duct 230 and the valve 246 on the circulating air duct 203 according to the set value. The unprocessed hot and humid air is adjusted to 0% to 40% by changing the opening ratio of the two valves. Under the condition of the dry hot air humidity meeting the granulation requirements, the proportion of hot and humid air is increased to reduce the energy loss caused by the processing of hot and humid air by the inlet air processor 140. In the fluidized granulation process, the pressure sensor located in the fluidized chamber 114 is always The pressure in the fluidizing chamber 114 is detected. Since the compressed air used by the spray gun 113 to atomize the adhesive increases the amount of air in the system, the pressure sensor located in the fluidizing chamber 114 detects that when the pressure in the fluidizing chamber 114 exceeds the set range of -100Pa to -2000Pa, the control system 220 starts the exhaust fan and opens the valve 244 located on the exhaust duct 191 to discharge the excess gas to ensure that the system operates within the set pressure range. According to the different configurations of the adhesive required for granulation, the exhaust gas is 2% to 15% of the total air volume of the system. The control system 220 continuously controls the short-circuit air volume and the exhaust air volume of the exhaust fan according to the temperature and humidity detection on the air inlet duct 170 and the pressure detection of the fluidizing chamber 114 of the main machine, so as to achieve the stability of the air supply temperature and humidity and the pressure of the fluidizing chamber 114, thereby ensuring the smooth progress of the granulation process.

[0052] After the fluidized bed completes the granulation process, it enters the drying state to complete the drying process of the wet material. In the drying stage, the control system 220 adjusts the proportion of the processed hot and humid air by controlling the valve 246 on the circulating air duct 203 and the valve 247 on the short-circuit air duct 230 according to the previously set drying temperature of 60°C to 90°C and the drying humidity of 2% to 15%, thereby ensuring that the processed hot and dry air meets the drying requirements.

[0053] The operation of the fluidized bed gas self-circulation device proposed by the present invention in the fluidized bed drying production process is the same as the drying condition in the fluidized bed granulation production process.

[0054] The present invention detects the temperature and humidity of the inlet air and the pressure of the fluidizing chamber 114 through the control system 220, accurately controls the exhaust fan to achieve the stable pressure of the fluidizing chamber 114, and reduces the exhaust of the fluidized bed by 85% to 98%, greatly reducing the environmental impact caused by the exhaust and the possible environmental risks. The valve 247 of the short-circuit air duct 230 and the valve 246 of the third section of the circulating air duct 203 are accurately controlled to achieve the stable working condition of the inlet air, ensure the stable operation of the fluidized bed system under different external environments, reduce the difficulty of operation, and improve the product quality.

[0055] The present invention connects the original open system into a closed self-circulating system by adding a circulating fan 160, a circulating air duct, and a short-circuit air duct 230 on the basis of the original fluidized bed system. According to the specific process of preparing products in the fluidized bed, the air inlet temperature and humidity settings and the pressure settings of the fluidizing chamber 114 in the granulation stage and the drying stage are completed; the granulation raw materials are put into the material bin 112, and the fluidized bed is started; the control system 220 monitors the pressure sensor located in the fluidizing chamber 114 to determine whether the pressure of the fluidizing chamber 114 is within the set range. When the liquid spraying gun 113 causes the pressure of the entire fluidized bed system to increase, the exhaust fan discharges part of the gas in the system to maintain the pressure in the fluidizing chamber 114 stable. The present invention improves the original fluidized bed system's all-gas emission mode to a small amount of gas emission, which greatly reduces the environmental impact and energy loss caused by fluidized bed gas emission. At the same time, the closed-loop system operation also greatly reduces the power consumed by the fan operation. The high-temperature and high-humidity gas circulated back is dehydrated by the air inlet processor 140 in the fluidized bed system. The dehydrated gas is heated by the steam heater 144. The treated dry hot air is mixed with the humid hot air from the short-circuit air duct 230 and sent into the fluidized bed through the air inlet duct 170. The temperature and humidity sensors on 170 monitor the incoming air temperature and humidity. The control system 220 adjusts the valve opening ratios on the third circulating air duct 203 and the short-circuit air duct 230 according to the monitored incoming air temperature and humidity. While ensuring that the incoming air temperature and humidity meet the requirements, the hot and humid air entering the air inlet processor 140 is reduced to a minimum, so as to reduce the energy consumed in the process of treating hot and humid air, thereby achieving energy-saving effects. At the same time, the effective guarantee of the air inlet control indicators reduces the impact of environmental changes on the air intake of the original system, reduces the difficulty of operation, and makes it easier to improve product quality.

[0056] In order to illustrate the beneficial effects of the present invention, the following experiments are used to illustrate.

[0057] Steam consumption can directly reflect production costs, so it is analyzed as a key economic indicator. Since steam heating is rarely used in the drying process under the self-circulation mode, only the process data of the granulation stage is selected during the analysis, and the drying process is not included in the analysis.

[0058] Data source: Real-time collection of circulating fluidized bed and traditional fluidized bed granulation processes.

[0059] The production batches and operation modes are shown in Table 1 below:

[0060] Table 1

[0061]

[0062] Analysis software: Minitab, Simca.

[0063] Analysis results: From the results in Table 1, it can be seen that the self-circulation granulation time is longer than the traditional granulation time, but the cumulative steam consumption is significantly reduced, especially in the operation mode of batch number 6-13-1, the granulation time is short and the cumulative steam consumption is small, which is only 2079 L. The experimental results show that the self-circulation granulation equipment of the present invention can significantly reduce the steam consumption.

[0064] Through the actual production comparison of 3 batches of traditional process and 5 batches of self-circulation process, from the energy perspective, the self-circulation mode can reduce the operating cost by 337 yuan. See the table below for details.

[0065] Table 2 Power consumption

[0066]

[0067] Table 3 Steam consumption

[0068]

[0069]

[0070] Table 4 Chilled water consumption

[0071]

[0072] From Table 2-4 we can see that:

[0073] Electricity consumption: traditional mode: 1.03kwh, self-circulation mode: 1.66kwh, additional cost 0.47 yuan.

[0074] Steam consumption: traditional mode: 3803L, self-circulation mode: 2543L, saving 441 yuan (33%).

[0075] Chilled water consumption: traditional mode: 2.3 yuan, self-circulation mode: 5.3 yuan, additional cost 3 yuan.

[0076] It can be seen that the self-circulation mode adopted by the present invention can save more expenses and reduce production costs compared with the traditional mode.

[0077] The above embodiments describe the present invention in detail, but the contents are only preferred embodiments of the present invention and cannot be considered to limit the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the present invention.

Claims

1. A method for self-circulation of fluidized bed gas, characterized in that: The following steps are involved: (1) Put the powdered material into the material bin of the fluidized bed main machine, and set the temperature and humidity required for the granulation and drying stages of the fluidized bed main machine according to the control system; (2) Start the fluidized bed main unit, and the control system starts working according to the pre-programmed program. First, the surface cooler and steam heater are turned on, the valves on the air supply pipe and the valves on the exhaust pipe are opened, and the exhaust fan is turned on. The fluidized bed system enters the working state, and the powdered material inside the material bin is fluidized; (3) The control system monitors the fluidization chamber pressure of the fluidized bed main unit. When the pressure sensor in the fluidized chamber detects that the pressure in the fluidized chamber reaches the range of -100Pa to -2000Pa, the valves on the first section of the circulating air duct, the valves on the second section of the circulating air duct, and the valves on the third section of the circulating air duct are opened, and the circulating fan is turned on. At the same time, the exhaust fan, the valves on the exhaust duct, and the valves on the air supply duct are closed, and the fluidized bed system enters the self-circulation state; (4) During the self-circulation operation, the control system monitors the flow rate, temperature, humidity and pressure of the hot dry air on the air inlet duct, and monitors the material temperature through the temperature sensor on the material bin. When the material temperature reaches 50°C~80°C, granulation begins; (5) During the fluidized bed granulation process, the control system detects the temperature and humidity of the inlet air according to the temperature and humidity sensor on the inlet air duct, and adjusts the valve on the short-circuit air duct and the valve on the third-section circulating air duct according to the set value. By changing the opening ratio of the two valves, the proportion of the hot and humid air that is not processed is adjusted; (6) During the fluidized granulation process, the pressure sensor in the fluidized chamber always detects the pressure in the fluidized chamber. When the pressure in the fluidized chamber exceeds the set range, the control system starts the exhaust fan and opens the valve on the exhaust duct to discharge excess gas to ensure that the system operates within the set pressure range; (7) After the fluidized bed completes the granulation process, it enters the drying state. The proportion of the treated hot and humid air is adjusted by controlling the valve on the third-section circulating air duct and the valve on the short-circuit air duct to ensure that the treated hot and dry air meets the drying requirements.

2. The method for self-circulation of fluidized bed gas according to claim 1, characterized in that: In step (1), in the granulation stage, the granulation temperature of the fluidized bed is 50°C to 80°C, and the relative humidity is 5% to 20%; in the drying stage, the drying temperature of the fluidized bed is 60°C to 90°C, and the relative humidity is 2% to 15%; in step (5), the proportion of untreated hot and humid air is controlled at 0% to 40%; in step (6), depending on the configuration of the adhesive required for granulation, the exhaust gas is 2% to 15% of the total air volume of the system.

3. A fluidized bed gas self-circulation device, used to implement the fluidized bed gas self-circulation method according to claim 1 or 2, characterized in that: include: Fluidized bed host, mixer, dust collector, air inlet processor, exhaust device, circulating fan, air inlet duct, air outlet duct, exhaust duct, circulating air duct, air supply duct and control system; wherein the air inlet of the fluidized bed host is connected to the mixer through the air inlet duct, and the air outlet is connected to the dust collector through the air outlet duct; the air outlet of the dust collector is connected to the exhaust duct and the circulating air duct through a duct; the exhaust duct is controlled by the exhaust device, and the circulating air duct is controlled by the circulating fan; the mixer is connected to the circulating air duct through a short-circuit air duct, and is connected to the air outlet of the air inlet processor through another duct; The air inlet is connected to the circulating air duct; the fluidized bed main unit includes a bracket, a buffer chamber, a material bin, a fluidizing chamber and a filter chamber which are connected in sequence from bottom to top and fixed by the bracket, and a spray gun arranged on the vulcanization chamber. The buffer chamber, the material bin, the fluidizing chamber and the filter chamber are tightly connected by a sealing ring and isolated from the outside world; the air inlet duct is provided with a dry hot air flow rate sensor, a temperature and humidity sensor and a pressure sensor; the air outlet duct is provided with a temperature and humidity sensor and a pressure sensor; a temperature sensor is provided on the material bin for detecting the granulation temperature during the granulation process and the drying temperature during the drying process; a pressure sensor is provided in the fluidizing chamber.

4. The fluidized bed gas self-circulation device according to claim 3, characterized in that: The exhaust device is selected from one of an exhaust fan, an exhaust valve or a vacuum pump.

5. The fluidized bed gas self-circulation device according to claim 3, characterized in that: The circulating air duct includes a first section circulating air duct, a second section circulating air duct and a third section circulating air duct; the air inlet end of the first section circulating air duct is connected to the air outlet of the dust collector, the air inlet of the circulating fan at the air outlet end and the air inlet of the exhaust duct; the air inlet end of the second section circulating air duct is connected to the air outlet of the circulating fan, and the air outlet end is connected to the air inlet end of the third section circulating air duct, the air outlet end of the supplementary air duct and the air inlet end of the short-circuit air duct; the air outlet end of the third section circulating air duct is connected to the air inlet end of the air inlet processor; A valve is arranged at the air inlet end of the first section of the circulating air duct, a valve is arranged at the air outlet end of the second section of the circulating air duct, and a valve is arranged at the air inlet end of the third section of the circulating air duct.

6. The fluidized bed gas self-circulation device according to claim 3, characterized in that: A valve is arranged at the air inlet end of the exhaust duct; a valve is arranged on the short-circuit air duct; a valve is arranged on the air supply duct; the air inlet of the buffer chamber is the air inlet of the fluidized bed main unit, and a valve is arranged on the air inlet to connect the air inlet duct; the air outlet of the filter chamber is the air outlet of the fluidized bed main unit, and a valve is arranged on the air outlet to connect the air outlet duct.

7. The fluidized bed gas self-circulation device according to claim 3, characterized in that: The air inlet handler includes an air inlet handler box and a primary filter, a medium filter, a surface cooler, a steam heater and a high efficiency filter arranged in sequence from the air inlet to the air outlet inside the air inlet handler box; the air inlet handler box is provided with a chilled water inlet and a steam inlet connected to the surface cooler and the steam heater, and a condensate outlet for connecting the chilled water and steam media outside the equipment.

8. The fluidized bed gas self-circulation device according to claim 3, characterized in that: The dust collector comprises a dust collector housing and a dust filter.

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