CN108851171A - A kind of blade redrying system and its control method with waste gas circulation function - Google Patents

Abstract

The invention relates to a blade redrying system with exhaust gas circulation function and its control method. The system includes a material inlet, a drying area and a moisture removal system, and also includes a pre-heating area, branch pipes and a control system. The pre-heating area is located between the drying area and the control system. Between the material inlets, the branch pipe includes a first branch pipe and a second branch pipe, so that a part of the exhaust gas discharged from the drying area to the moisture exhaust duct enters the preheating area; the control system is a closed-loop control system, including a detection device , comparators, actuators and controllers. The control method forms a closed-loop control through real-time comparison of the control system. On the basis of the original equipment, the present invention forms a preheating zone in the material inlet area, fully utilizes the waste gas rich in a large amount of heat energy, achieves the purpose of rapidly increasing the temperature of the inlet material, effectively relieves the subsequent material processing temperature and moisture control pressure, and reduces the subsequent material. The amount of steam used for processing reduces the energy consumption of the whole blade rebaking machine and improves the quality of blade rebaking.

Description

A blade redrying system with exhaust gas circulation function and its control method

technical field

The invention relates to a blade redrying system and a control method thereof, in particular to a blade redrying system with exhaust gas circulation function and a control method thereof.

Background technique

Leaf redrying machine is the main equipment in the leaf threshing and redrying treatment line. Its purpose is to adjust the moisture in the tobacco sheet, remove the miscellaneous gas in the tobacco sheet, kill the pests and germs in the tobacco sheet, and make the tobacco sheet more suitable It is suitable for storage, alcoholization and artificial fermentation, so that the quality of tobacco sheets tends to be more standardized and consistent.

The leaf rebaking machine is mainly composed of the following parts: feeding end, active and passive section of the pressure mesh belt, upper blowing section in the drying area, lower air blowing section in the drying area, cooling section, moisture exhaust duct, dampening section, discharge end, pipe road system, conveyor belt, insulation door panels, etc.

After the material enters the blade re-baking machine, it is firstly baked in four longer drying areas along with the mesh belt. During operation, the wet tobacco sheet is dried by the circulating hot air blown from bottom to top. With the operation of the material and the increase of the baking time, the temperature of the smoke sheet gradually rises, the water in the smoke sheet is evaporated, and the evaporated water with miscellaneous gas is discharged to the outside by the fan. When the smoke sheet reaches a certain temperature When the mold in the smoke sheet is killed. The material continues to move forward, and the temperature of the tobacco sheet gradually decreases. After most of the water evaporates, the circulating hot air dries the tobacco sheet from top to bottom, and the humid air continues to be discharged until the moisture content of the tobacco sheet at the exit of the drying area reaches 8~ 10%.

After the smoke sheet comes out of the drying zone, it enters the cooling zone. In the cooling zone, the lower temperature circulating air is used to reduce the temperature of the smoke sheet to 35-45°C, so as to provide technological conditions for the remoisture of the smoke sheet.

Finally, the smoke sheet passes through a longer moisture resurgence channel. During operation, atomized water and steam are sprayed from top to bottom, and then from bottom to top. After the material fully absorbs heat and moisture, it is sent to the discharge end.

At present, the temperature of the hot air used to heat and dry the tobacco leaves in each drying zone of the leaf redrying machine is 60-90°C, and the temperature of the hot air discharged into the atmosphere after passing through the tobacco leaves will decrease by 5-8°C, but it still contains a lot of heat. Heat energy is lost without effective recycling, resulting in a large waste of energy, which is not conducive to energy saving and consumption reduction of equipment.

Contents of the invention

In view of the above problems, in order to improve the thermal efficiency of the blade rebaking machine, a blade rebaking system and its control method with exhaust gas circulation function of the present invention are proposed. The system includes a material inlet, a drying area and a moisture removal system. The material inlet is used for The leaf material to be baked is transported to the drying area, and the drying area is used to bake the leaf material. Exhaust gas discharge, the system also includes preheating zone, branch pipe and control system, where:

The preheating zone is located between the drying zone and the material inlet, and the blade material to be baked enters the preheating zone from the material inlet to be preheated, and then enters the drying zone for baking;

The branch pipes include a first branch pipe and a second branch pipe, the rear end of the preheating zone is connected to the front end of the moisture exhaust duct through the first branch pipe, and the front end of the preheating zone is connected to the exhaust air duct through the second branch pipe. The rear end of the tidal air pipe is connected so that a part of the exhaust gas discharged from the drying area to the tidal air pipe enters the preheating area, preheats the blade material in the preheating area, and is aligned with the forward direction of the material. Reverse circulation, exhaust gas enters the moisture exhaust duct through the second branch pipe, and finally is discharged through the moisture exhaust duct, the branch pipe and the preheating zone form a waste gas circulation area;

The control system is a closed-loop control system, including a detection device, a comparator, an actuator and a controller, wherein the detection device includes a plurality of temperature sensors, which are located at different positions in the exhaust gas circulation area, and are used to collect temperatures in different areas; the comparator is used for Comparing the temperature difference in different areas; the actuator is used to adjust the flow of exhaust gas entering the first branch pipe and the air pressure in the preheating area; the controller is used to adjust the actuator according to the result of the comparator.

Preferably, the actuator includes an angle actuator and a fan, and the opening of the angle actuator and the frequency of the fan are adjusted by the controller. The system also includes an odor treatment system through which the exhaust gas flowing through the moisture removal system is finally discharged.

Preferably, the preheating zone is a conveyor belt with a heat-retaining and moisture-retaining cover.

Preferably, the system further includes a scraper feeder, the preheating zone is a vertical pipe, the material inlet is located at the upper end of the vertical pipe, and the material falls into the scraper feeder after heat exchange with exhaust gas from the vertical pipe.

Preferably, there are at least two temperature sensors, one of which is located in the exhaust air pipe and adjacent to the exhaust gas inlet of the first branch pipe, and is used to detect the temperature of the exhaust gas discharged from the drying area, and the other temperature sensor is located in the preheating Zone, used to detect the temperature of the preheating zone.

Preferably, the fan includes a tidal exhaust fan and a circulation fan, the tidal exhaust fan is located in the tidal exhaust duct, and is used to make the waste gas flow to the odor treatment system, and the circulation fan is located in the second branch pipe, and is used to make part of the exhaust gas flow to the odor treatment system. The direction of material delivery is opposite to the direction of circulation.

Preferably, the controller is a PID controller.

Preferably, the detection device further includes an anemometer, located in the first branch pipe, for detecting the flow velocity of the exhaust gas.

A control method of a blade rebaking system with exhaust gas circulation function, which is applied to the above blade rebaking system with exhaust gas circulation function, and the control method includes:

One temperature sensor in the detection device collects the temperature of the exhaust gas discharged from the drying area to form a temperature value A, and the other temperature sensor collects the temperature of the low-temperature exhaust gas after passing through the preheating zone to form a temperature value B. At the same time, the anemometer collects the wind speed of the exhaust gas entering the first branch pipe Form the wind speed value V;

Comparing with the comparator to form the difference C, when the difference C is large, the system uses the actuator composed of the angle actuator, the exhaust fan and the circulation fan to adjust the first stage after the operation and processing of the PID controller. The flow rate of the exhaust gas in the branch pipe and the air pressure in the preheating area, that is, by increasing the opening of the angle actuator, increasing the frequency of the exhaust fan, and reducing the frequency of the circulating fan, it is possible to increase the air intake of the branch pipe, reduce the amount of exhaust gas discharged from the preheating area, and increase the preheating area. The effect of pressure in the heating area reduces the difference C, and vice versa when the difference C is small;

A real-time comparison is formed through the feedback value of the temperature sensor, thereby forming a closed-loop control.

On the basis of the original equipment, the present invention forms a preheating area in the material inlet area by adding a waste gas recycling system in the drying area, and makes full use of the waste gas rich in a large amount of heat energy, so as to achieve the purpose of rapidly increasing the temperature of the inlet material and effectively ease the subsequent material processing. The temperature and moisture control the pressure, reduce the amount of steam used for subsequent material processing, and then reduce the energy consumption of the whole machine for leaf redrying, and improve the quality of leaf redrying processing.

Description of drawings

Fig. 1 is a schematic diagram of a blade redrying system with exhaust gas circulation function;

Fig. 2 is a schematic diagram of another blade redrying system with exhaust gas circulation function;

Fig. 3 is a schematic diagram of the closed-loop control of the blade redrying system with exhaust gas circulation function;

Among them: 1, 7—temperature sensor; 2—tidal exhaust fan; 3—tidal exhaust air pipe; 4—angle actuator; 5—anemometer; 6—first branch pipe; 8—circulation fan; 9—second branch pipe; 10—conveyor belt; 11—scraper feeder.

Detailed ways

In order to improve the thermal efficiency of the leaf redrying machine, the waste gas from each drying area is introduced to the feed end to preheat the incoming tobacco leaves, so as to reduce the steam consumption in the drying area of the leaf redrying machine, thereby reducing the energy consumption of the leaf redrying machine.

As shown in Figure 1, a blade redrying system with exhaust gas circulation function, the system includes the material inlet, namely the tobacco sheet inlet, drying area and moisture exhaust system, the exhaust gas in the drying area enters the odor treatment system through the moisture exhaust air duct and is discharged , the system also includes a preheating zone, a first branch pipe 6, a second branch pipe 9 and a control system, wherein: a preheating zone, located between the first branch pipe 6 and the second branch pipe 9, is used to introduce exhaust gas into the area to be dried The material is preheated; the first branch pipe 6 is located at the lower end of the moisture exhaust duct 3, and is connected to the moisture exhaust duct 3 and the preheating zone, and is used to introduce the waste gas discharged into the moisture exhaust duct 3 in the drying area into the preheating zone; Two branch pipes 9, located at the upper end of the exhaust air duct 3, connected to the preheating zone and the exhaust air duct 3, are used to lead the exhaust gas back to the exhaust air duct 3 to form a preheating area for exhaust gas circulation; the control system is a closed-loop control system , including a detection device, a comparator, an actuator and a controller, wherein the detection device includes a temperature sensor, which is located at different positions in the preheating area, and is used to collect the temperature of different areas; the comparator is used to compare the temperature difference of different areas; The controller includes an angle actuator 4 and a fan, which are used to adjust the flow of exhaust gas entering the first branch pipe 6 and the air pressure of the preheating area; the controller is used to adjust the actuator according to the result of the comparator to control the temperature of the area.

In one embodiment, the preheating zone is a conveyor belt 10 with a thermal insulation and moisturizing cover, the material inlet is at the same height as the conveyor belt 10, the conveyor belt 10 forms a preheating zone, and the first branch pipe 6, the conveyor belt 10 , The second branch pipe 9 forms a preheating area for exhaust gas to circulate. The fan includes a tidal exhaust fan 2 and a circulation fan 8. The tidal exhaust fan 2 is located in the tidal exhaust duct 3 for making the waste gas flow to the odor treatment system, and the circulation fan 8 is located on the conveyor belt 10 for making part of the exhaust gas Flow in the direction opposite to the direction in which the material in the conveyor belt 10 is transported. There are at least two temperature sensors, one temperature sensor 1 is located in the exhaust air duct 3 for detecting the temperature of exhaust gas discharged from the drying area, and the other temperature sensor 7 is located on the conveyor belt 10 for detecting the temperature of the preheating area. In this embodiment, a section of closed preheating area is designed at the entrance of the blade re-roasting machine, such as a belt conveyor or a mesh belt conveyor. The discharge end leads to the inside of the closed cavity of the conveyor, and is discharged to the outside from the feed end of the conveyor. In the closed section of the conveyor, the running direction of the material is opposite to that of the hot air, and the tobacco leaves are heated by means of heat exchange. The length of the closed conveyor can be determined according to the needs.

In another embodiment, as shown in Figure 2, the system also includes a scraper feeder 11, the material inlet is located at the upper part of the vertical part of the second branch pipe 9, and the material passes through the vertical part of the second branch pipe 9 and the waste gas After the heat exchange, it falls into the scraper feeder 11, the vertical part of the second branch pipe 9 forms a preheating zone, and the first branch pipe 6 and the second branch pipe 9 form a preheating zone for exhaust gas circulation. The fan includes a moisture exhaust fan 2 and a circulation fan 8, the moisture exhaust fan 2 is located in the moisture exhaust duct 3, and is used to make the waste gas flow to the odor treatment system, and the circulation fan 8 is located at the upper end of the second branch pipe 9, and is used to make the waste gas flow to the odor treatment system. Part of the exhaust air circulates in the opposite direction to the direction in which the material is conveyed. There are at least two temperature sensors, of which one temperature sensor 1 is located in the moisture exhaust duct 3 for detecting the temperature of exhaust gas discharged from the drying area, and the other temperature sensor 7 is located at the upper end of the second branch pipe 9 for detecting the temperature of the preheating area . In this embodiment, a vertical and relatively sealed pipeline is designed at the entrance of the blade re-roasting machine, and the high-temperature exhaust gas from each drying area is passed into the pipeline from the bottom of the vertical pipeline by lengthening the moisture-discharging pipeline of the roasting machine. It is discharged from the upper part of the pipe, and the tobacco leaf raw material enters the interior of the pipe from the upper part of the pipe and is discharged from the lower part of the pipe. Inside the vertical pipe, the material running direction is opposite to the hot air running direction, and the tobacco leaves are heated by heat exchange. The length of the standpipe can be determined as required. This embodiment differs from the previous one in that the preheating zone is constructed differently. The characteristics of the conveyor belt with heat preservation and moisturizing cover are: the preheating area is narrow and long, the physical distance for the material to absorb heat energy and moisture is relatively large, the time for the material per unit volume in the preheating area to absorb heat energy and moisture is relatively long, and the preheating The overall volume of the area is small, which is easy to increase the internal pressure, and is convenient for fully absorbing heat energy and moisture; the characteristics of the scraper feeder are: the overall volume of the preheating area is large, and the material and exhaust gas can Full contact, and this method enables the preheating area to form a relatively stable temperature and humidity environment, which is more suitable for the situation where the flow of incoming materials is large.

In one embodiment, the controller is a PID controller.

In one embodiment, the detection device further includes an anemometer 5 located at the front end of the first branch pipe 6 for detecting the flow velocity of the exhaust gas in the preheating area.

This system can set the temperature of the preheating zone on the premise that the temperature of the exhaust gas in the drying zone is not higher than that of the drying zone. The temperature sensor is used to collect temperature data, and the anemometer 5 is used to monitor the flow rate of the exhaust gas entering the preheating zone, and the angle is adjusted through PID adjustment. The opening of the device 4 is controlled to control the amount of exhaust gas entering the pre-heating zone, forming an automatic feedback control of the temperature in the pre-heating zone and forming a closed-loop control. As shown in Figure 1-3, the exhaust gas from the drying area is drawn away by the exhaust fan 2 through the exhaust air pipe 3, and the exhaust gas enters the bottom of the mesh belt in the tobacco sheet preheating area through the branch pipe, and the exhaust gas flows upward to heat the tobacco sheet. At the same time, the circulation fan drives the gas flow in the heating area, and forms a direct impact and full contact with the incoming material. The low-temperature exhaust gas is taken away by the circulation fan 8 and returned to the moisture exhaust duct 3, and so on, so as to achieve the temperature rise of the inlet smoke sheet. heating.

As shown in Figure 1, the material passes through a conveyor belt 10 with a heat-preserving and moisturizing cover before entering the blade re-baking machine. The relatively high temperature (75°C-100°C) and relatively humid exhaust gas from the drying area is partly diverted by branch pipes to the conveyor belt with heat preservation and moisturizing cover during the process of transporting the moisture exhaust air pipe 3 to the odor treatment system In the preheating area formed by 10, after the heat energy and moisture are fully absorbed by the material with a low inlet temperature, the low-temperature exhaust gas is brought back to the rear end of the exhaust air pipe 3 by the branch pipe through the action of the circulating fan 8 and taken away for treatment. Such a reciprocating cycle achieves the purpose of preheating and pre-humidifying the inlet materials, reducing the steam consumption in the drying zone of the leaf redrying machine, improving the thermal efficiency of the leaf redrying machine and reducing the energy consumption of the leaf redrying machine.

During this process, the temperature sensor 1 collects the temperature of the exhaust gas discharged from the drying area to form a temperature value A, and the temperature sensor 7 collects the temperature of the low-temperature exhaust gas after passing through the preheating area to form a temperature value B, which is compared by a comparator to form a difference C. At the same time, the anemometer 5 collects the wind speed of the exhaust gas entering the branch pipe to form a wind speed value V. When the difference C is large, after the system is processed by the PID controller, the actuator composed of the angle actuator 4, the tidal exhaust fan 2 (frequency conversion control), and the circulation fan 8 (frequency conversion control) is used to adjust the flow rate of the branch pipe. The flow rate of the exhaust gas and the air pressure in the preheating area, that is, increase the opening of the angle actuator 4, increase the frequency of the tidal exhaust fan 2, and reduce the frequency of the circulation fan 8, and form a real-time comparison through the feedback value of the temperature sensor, thereby forming a closed-loop control to achieve an increase The intake air volume of the branch pipe, reducing the exhaust gas volume in the preheating area, and increasing the pressure in the preheating area reduce the difference C to ensure that the materials passing through the preheating area fully absorb heat energy and moisture, and vice versa when the difference C is small.

The above-mentioned specific embodiments are only used to illustrate the present invention, wherein the structure and connection mode of each component can be changed, and any equivalent transformation and improvement carried out on the basis of the technical solution of the present invention should not be excluded from the present invention. outside the scope of protection of the invention.

Claims (10)

1. a kind of blade redrying system with waste gas circulation function, which includes material inlet, dry section and humidity discharging system, The material inlet is for conveying blade material to be baked to dry section, and the dry section is for drying blade material Roasting, the humidity discharging system is connect by humidity discharging air hose with dry section, for baking in dry section to be discharged using the exhaust gas finished, It is characterized in that, the system further includes pre-add hot-zone, branch pipe and control system, wherein：

Pre-add hot-zone, between the dry section and the material inlet, blade material to be baked is from the material inlet It is introduced into the pre-add hot-zone preheating, the dry section is entered back into and is toasted；

The branch pipe includes the first branch pipe and the second branch pipe, and the rear end of the pre-add hot-zone passes through the first branch pipe and the humidity discharging wind The front end of pipe connects, and the front end of the pre-add hot-zone is connect by the second branch pipe with the rear end of the humidity discharging air hose, so that from institute The a part for stating the exhaust gas that dry section is discharged to the humidity discharging air hose enters the pre-add hot-zone, to the blade object in pre-add hot-zone Material is preheated, and is inversely circulated with material direction of advance, and exhaust gas enters the humidity discharging air hose through second branch pipe again, most It is discharged by the humidity discharging air hose, the branch pipe and pre-add hot-zone form exhaust gas circulating area；

Control system is closed-loop control system, including detection device, comparator, actuator and controller, wherein detection device packet Multiple temperature sensors are included, positioned at the different location of the exhaust gas circulating area, for acquiring the temperature of different zones；Comparator For comparing the difference of different zones temperature；Actuator is used to adjust the flow and pre-add hot-zone gas into the exhaust gas of the first branch pipe Pressure；Controller is used to adjust the actuator according to the result of comparator.

2. the blade redrying system according to claim 1 with waste gas circulation function, which is characterized in that the actuator Including angle actuator and blower, the aperture of angle actuator and the frequency of blower are adjusted by the controller.

3. the blade redrying system according to claim 2 with waste gas circulation function, which is characterized in that the system is also wrapped Peculiar Odor Treatment System is included, the exhaust gas for flowing through humidity discharging system is discharged eventually by the Peculiar Odor Treatment System.

4. the blade redrying system according to claim 3 with waste gas circulation function, which is characterized in that the preheating Area is the conveyer belt with heat and moisture preserving housing.

5. the blade redrying system according to claim 3 with waste gas circulation function, which is characterized in that the system is also wrapped Include scraper plate feeder, pre-add hot-zone is vertical pipeline, and material inlet is located at vertical pipeline upper end, material from vertical pipeline by with Scraper plate feeder is fallen into after exhaust gas heat exchange.

6. the blade redrying system according to claim 1 with waste gas circulation function, which is characterized in that the temperature passes Sensor at least there are two, one of temperature sensor is located in the humidity discharging air hose and the exhaust gas of neighbouring first branch pipe Inlet, for detecting the temperature of dry section discharge exhaust gas, another temperature sensor is located at pre-add hot-zone, for detecting pre-add Hot zone temperature.

7. the blade redrying system according to claim 1 with waste gas circulation function, which is characterized in that the blower packet Moisture-eliminating blower and circulating fan are included, the moisture-eliminating blower is located at humidity discharging air hose, described for making waste gas flow direction Peculiar Odor Treatment System Circulating fan is located at the second branch pipe, for making portion to circulate with the contrary direction that material conveys.

8. the blade redrying system according to claim 1 with waste gas circulation function, which is characterized in that the controller For PID controller.

9. the blade redrying system according to claim 8 with waste gas circulation function, which is characterized in that detection device is also Including anemobiagraph, it is located at the first branch pipe, for detecting the flow velocity of exhaust gas.

10. a kind of control method of the blade redrying system with waste gas circulation function, which is characterized in that be applied to claim There is the blade redrying system of waste gas circulation function, which includes described in 9：

The exhaust gas temperature formation temperature numerical value A that temperature sensor acquisition in detection device is discharged from dry section, it is another A temperature sensor acquires the low temperature waste gas temperature formation temperature numerical value B behind pre-add hot-zone, while anemobiagraph acquisition enters The exhaust gas wind speed of first branch pipe forms wind speed numerical value V；

It is compared to form difference C by comparator, when difference C is larger, after system passes through PID controller calculation process, benefit With angle actuator, moisture-eliminating blower, circulating fan three constitute actuator come adjust into the exhaust gas of the first branch pipe flow and The air pressure of pre-add hot-zone reaches increasing that is, by increasing angle actuator aperture, increasing moisture-eliminating blower frequency, reduction circulating fan frequency The effect for adding branch pipe air inflow, reducing preheated volumes discharge exhausted air quantity, increasing pressure in preheated volumes, reduces difference C, when Difference C is then on the contrary when smaller；

Real-time comparison is formed by temperature sensor fed back values, to form closed-loop control.