Drying chamber air circulation energy-saving system and method

Abstract

The invention relates to the technical field of environmental protection and energy conservation, in particular to an air circulation energy-saving system and method for a drying chamber. The temperature and humidity sensor is used for detecting the moisture content of outdoor air; the first fresh air device communicates with the drying chamber and is used for providing fresh air for dehumidification and heating for the drying chamber; the hot air circulation unit communicates with the drying chamber to form circulation and is used for heating air in the drying chamber; an inlet of the waste gas incineration device communicates with the drying chamber, an outlet of the waste gas incineration device communicates with a chimney through a smoke exhaust pipeline, and a smoke temperature sensor is arranged on the smoke exhaust pipeline; the second fresh air device communicates with the drying chamber, and a heat exchanger is arranged between the second fresh air device and the smoke exhaust pipeline to heat fresh air fed into the drying chamber; the second fresh air device is additionally arranged on the basis of the first fresh air device, the heat exchanger is arranged between the second fresh air device and the smoke exhaust pipeline, fresh air can be heated through high-temperature smoke, the outdoor air moisture content and the smoke temperature condition are combined, the cooling capacity and heat consumption of the first fresh air device can be reduced, and heat consumption of the hot air circulation unit is reduced.

Description

Technical Field

[0001] This invention relates to the field of environmental protection and energy-saving technology, and in particular to an energy-saving system and method for air circulation in a drying room. Background Technology

[0002] Drying chambers are widely used in industrial production sectors such as automobiles and furniture. The air circulation system of a drying chamber typically consists of three systems: 1. Hot air circulation system: This system replenishes the drying chamber with heat through natural gas combustion or electric heating to maintain the process temperature; 2. Exhaust system: The materials being dried generate a large amount of toxic and harmful substances such as VOCs during the drying process. These substances cannot be directly discharged into the outdoor atmosphere and often require incineration before release; 3. Fresh air system: To ensure that the concentration of organic gases in the drying chamber does not exceed the lower explosive limit, a fresh air system is installed in addition to the exhaust system to dilute the concentration of harmful gases. Because the three air circulation systems in a drying chamber operate independently and each consumes energy, the overall energy consumption of the drying chamber is high, resulting in high production costs for enterprises. Summary of the Invention

[0003] The purpose of this invention is to provide an energy-saving air circulation system and method for a drying chamber, thereby solving the problems existing in the prior art. To achieve the above objective, this invention provides the following technical solution:

[0004] In a first aspect, the present invention provides an energy-saving air circulation system for a drying chamber, comprising:

[0005] Drying room;

[0006] Temperature and humidity sensor, used to detect the humidity content of outdoor air;

[0007] A first fresh air unit is connected to the drying chamber and is used to provide it with dehumidified and heated fresh air;

[0008] A hot air circulation unit is connected to the drying chamber to form a circulation, which is used to heat the air in the drying chamber;

[0009] The waste gas incineration device has its inlet connected to the drying chamber and its outlet connected to a chimney through a flue pipe. A flue gas temperature sensor is installed on the flue pipe.

[0010] The second fresh air device is connected to the drying chamber, and a heat exchanger is provided between it and the exhaust duct to heat the fresh air supplied into the drying chamber.

[0011] As a further technical solution, air valves are provided on the pipes connecting the first fresh air device and the second fresh air device to the drying chamber.

[0012] As a further technical solution, a fresh air temperature sensor is installed on the pipe connecting the heat exchanger and the drying chamber.

[0013] As a further technical solution, an exhaust fan is provided between the waste gas incineration device and the drying chamber.

[0014] As a further technical solution, air valves are provided on the pipes connecting the exhaust pipe to the inlet and outlet of the heat exchanger.

[0015] As a further technical solution, a flue gas induced draft fan is provided between the flue gas duct and the hot end inlet of the heat exchanger.

[0016] As a further technical solution, the first fresh air device is an air handling unit.

[0017] As a further technical solution, the second fresh air device is a fresh air fan box.

[0018] As a further technical solution, a control system is also included that is connected in communication with the drying chamber, the first fresh air device, the hot air circulation unit, the second fresh air device, the waste gas incineration device, the temperature and humidity sensor, and the flue gas temperature sensor.

[0019] In a second aspect, the present invention provides a method for operating the drying chamber air circulation energy-saving system as described in the first aspect, comprising the following steps:

[0020] The system obtains the outdoor air humidity content, turns on the drying room, hot air circulation unit and waste gas incineration device and automatically switches the working mode according to the operating conditions by the control system.

[0021] When the outdoor air humidity exceeds the first threshold, only the first fresh air device is turned on. The outdoor fresh air is first cooled and dehumidified by the first fresh air device and then heated to the first set temperature before being sent to the drying room.

[0022] When the outdoor air humidity is greater than the second threshold and less than the first threshold, and the exhaust temperature is higher than the temperature threshold, both the first fresh air device and the second fresh air device are turned on. A set proportion of outdoor fresh air is cooled and dehumidified by the first fresh air device and then heated to the set temperature before being sent to the drying room. The remaining proportion of outdoor fresh air is sent to the heat exchanger by the second fresh air device and heated to the second set temperature before being sent to the drying room.

[0023] When the outdoor air humidity is less than the second threshold and the exhaust temperature is higher than the temperature threshold, only the second fresh air device is turned on. The outdoor fresh air is sent to the heat exchanger through the second fresh air device, heated to the second set temperature, and then sent to the drying room.

[0024] The beneficial effects of the present invention are as follows:

[0025] (1) The present invention adds a second fresh air device on the basis of the first fresh air device, and a heat exchanger is installed between the second fresh air device and the exhaust pipe. The high temperature flue gas can be used to heat the fresh air. Considering the outdoor air humidity and flue gas temperature, it can achieve the purpose of reducing the cold and heat consumption of the first fresh air device and reducing the heat consumption of the hot air circulation unit while ensuring the drying quality and speed.

[0026] (2) The present invention sets three working modes. In the first working mode, only the first fresh air device is turned on. In the second working mode, both fresh air devices are turned on and the ratio of their fresh air volume is adjustable. In the third working mode, only the second fresh air device is turned on. The mode is switched according to the outdoor air humidity and flue gas temperature through the control system. Different working modes are adopted in different working environments, so that the system is not only flexible, but also maximizes the reduction of energy consumption. Attached Figure Description

[0027] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute a limitation thereof. It should also be understood that these drawings are for simplicity and clarity and are not necessarily drawn to scale. The invention will now be described and explained with additional features and details using the drawings, wherein:

[0028] Figure 1 A schematic diagram of the drying chamber air circulation energy-saving system is shown in an embodiment of the present invention.

[0029] In the diagram: 1. Drying chamber; 2. First fresh air unit; 3. Hot air circulation unit; 4. Waste gas incineration device; 5. Exhaust fan; 6. Chimney; 7. Heat exchanger; 8. Flue gas induced draft fan; 9. Second fresh air unit; 10. Flue gas temperature sensor; 11. Fresh air temperature sensor; 12. First air valve; 13. Second air valve; 14. Third air valve; 15. Fourth air valve; 16. Temperature and humidity sensor. Detailed Implementation

[0030] The technical solutions in typical embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0031] Example 1

[0032] like Figure 1 As shown, this embodiment provides an energy-saving air circulation system for a drying room, including a drying room 1, a temperature and humidity sensor 16, a first fresh air device 2, a hot air circulation unit 3, a waste gas incineration device 4, a second fresh air device 9, ductwork and a control system, etc.

[0033] The hot air circulation unit 3 is connected to the drying chamber 1 to form a circulation, which is used to heat the air in the drying chamber 1. The hot air circulation unit 3 draws the air in the drying chamber 1 and heats it to about 100°C before sending it into the drying chamber 1.

[0034] The waste gas incineration device 4 has its inlet connected to the drying chamber 1, and its outlet connected to the chimney 6 via a flue pipe. A flue gas temperature sensor 10 is installed on the flue pipe. An exhaust fan 5 is also installed between the waste gas incineration device 4 and the drying chamber 1. The exhaust fan 5 draws exhaust air from the drying chamber 1, sends it to the waste gas incineration device 4 for treatment, and then sends it to the chimney 6 and discharges it into the outdoor atmosphere.

[0035] The flue gas temperature sensor 10 installed on the flue gas exhaust duct can detect the temperature of the flue gas in the flue gas exhaust duct and can be used as an indicator for switching working modes.

[0036] Temperature and humidity sensor 16 is used to detect the humidity content of outdoor air and can be used as an indicator for switching operating modes.

[0037] The first fresh air device 2 is connected to the drying chamber 1 and is used to provide it with dehumidified and heated fresh air. In this embodiment, the first fresh air device 2 is an air handling unit (AHU), which can cool and dehumidify the outdoor fresh air and then reheat it (heat it to a first set temperature, which is 25°C in this embodiment) and then send it into the drying chamber 1.

[0038] During operation, the drying chamber 1, the hot air circulation unit 3, and the waste gas incineration device 4 are always on. Using the above technical solution, when the outdoor air humidity is greater than the first threshold (the first threshold is 20g / kg), the first fresh air device 2 is turned on. The outdoor fresh air is cooled and dehumidified by the first fresh air device 2 and then heated to the first set temperature before being sent to the drying chamber 1. The hot air circulation unit 3 draws air from the drying chamber 1 and heats it to about 100°C before sending it to the drying chamber 1. The exhaust fan 5 draws exhaust air from the drying chamber 1 and sends it to the waste gas incineration device 4 for treatment before sending it to the chimney 6 and discharging it into the outdoor atmosphere.

[0039] It also includes a second fresh air device 9, which is connected to the drying chamber 1 and has a heat exchanger 7 between it and the exhaust duct to heat the fresh air supplied to the drying chamber 1. In this embodiment, the second fresh air device 9 is a fresh air fan box. Outdoor fresh air can be filtered and pressurized by the second fresh air device 9 and then sent to the heat exchanger 7.

[0040] When the technical solution with a second fresh air device 9 is adopted, when the outdoor air humidity is greater than the second threshold (the second threshold is 15g / kg) and less than the first threshold (20g / kg), and the exhaust gas temperature is higher than the temperature threshold (the temperature threshold is 120℃), both the first fresh air device 2 and the second fresh air device 9 are turned on. A set proportion of outdoor fresh air is cooled and dehumidified by the first fresh air device 2 and then heated to the set temperature before being sent to the drying room 1. The remaining proportion of outdoor fresh air is sent to the heat exchanger 7 by the second fresh air device 9 and heated to the second set temperature before being sent to the drying room 1.

[0041] When the outdoor air humidity is less than the second threshold (15g / kg) and the exhaust temperature is higher than the temperature threshold (120℃), only the second fresh air device 9 is turned on. The outdoor fresh air is sent to the heat exchanger 7 through the second fresh air device 9 and heated to the second set temperature (the second set temperature is 80℃) before being sent to the drying room 1.

[0042] It should be noted that the selection of the first threshold, the second threshold, the first set temperature, the second set temperature, and the temperature threshold is determined according to the actual situation and is not limited to the values ​​given in this embodiment.

[0043] In this embodiment, a second fresh air device is added on the basis of the first fresh air device, and a heat exchanger 7 is installed between the second fresh air device and the exhaust duct. The high-temperature flue gas can be used to heat the fresh air. Taking into account the outdoor air humidity and flue gas temperature, it is possible to reduce the cooling and heating consumption of the first fresh air device and the heat consumption of the hot air circulation unit while ensuring the drying quality and speed.

[0044] In this embodiment, both the first fresh air device 2 and the second fresh air device 9 are equipped with air valves on the pipes connecting to the drying chamber 1. Specifically, the air valve on the pipe of the first fresh air device 2 is a fourth air valve 15, and the air valve on the pipe of the second fresh air device 9 is a third air valve 14. The pipes of the two fresh air devices share a single pipe connecting to the drying chamber 1. The proportion of fresh air from the two fresh air devices can be adjusted by adjusting the third air valve 14 and the fourth air valve 15.

[0045] A fresh air temperature sensor 11 is installed on the pipe connecting the heat exchanger 7 and the drying chamber 1 to detect the fresh air temperature after heat exchange in real time.

[0046] The flue gas duct is equipped with air valves on both the inlet and outlet of the heat exchanger 7 and the flue gas exhaust duct, namely the first air valve 12 and the second air valve 13. A flue gas induced draft fan 8 is installed between the flue gas duct and the hot end inlet of the heat exchanger 7, which can introduce high-temperature flue gas into the heat exchanger 7.

[0047] In this embodiment, the first air valve 12, the second air valve 13, the third air valve 14, and the fourth air valve 15 are all electric air valves.

[0048] It also includes a control system that is connected via communication to the drying chamber 1, the first fresh air unit 2, the hot air circulation unit 3, the second fresh air unit 9, the waste gas incineration unit 4, the temperature and humidity sensor 16, the air valve, and the flue gas temperature sensor 10.

[0049] Example 2

[0050] This embodiment provides a method for operating the drying chamber air circulation energy-saving system as described in Embodiment 1, including the following steps:

[0051] The system obtains the outdoor air humidity content, and the drying chamber 1, hot air circulation unit 3 and waste gas incineration device 4 are turned on and the control system automatically switches the working mode according to the operating conditions.

[0052] When the temperature and humidity sensor 16 detects that the outdoor air moisture content is greater than 20g / kg (the first threshold value in this embodiment is 20g / kg, the same below), the first air valve 12, the second air valve 13 and the third air valve 14 are closed, and the first fresh air device 2, the hot air circulation unit 3, the waste gas incineration device 4, the exhaust fan 5 and the fourth air valve 15 are opened. At this time, the outdoor fresh air is first cooled and dehumidified by the first fresh air device 2 and then heated to about 25℃ (the first set temperature value in this embodiment is 25℃, the same below). It is then sent to the drying chamber 1 by the fan of the first fresh air device 2. The hot air circulation unit 3 draws air from the drying chamber 1 and heats it to about 100℃ before sending it to the drying chamber 1. The exhaust fan 5 draws exhaust air from the drying chamber 1 and sends it to the waste gas incineration device 4 for treatment before sending it to the chimney 6 and discharging it into the outdoor atmosphere.

[0053] When the temperature and humidity sensor 16 detects that the outdoor air humidity is greater than 15g / kg (the second threshold value in this embodiment is 15g / kg, the same below) and less than 20g / kg, and the flue gas temperature sensor 10 detects that the exhaust gas temperature is higher than 120℃ (the temperature threshold value in this embodiment is 120℃, the same below), the first air valve 12, the second air valve 13, and the third air valve 14 are opened, and the first fresh air device 2, the hot air circulation unit 3, the waste gas incineration device 4, the exhaust fan 5, the flue gas induced draft fan 8, the second fresh air device 9, and the fourth air valve 15 are opened. At this time, 50% (the specific ratio can be adjusted) of the outdoor fresh air is cooled and dehumidified by the first fresh air device 2 before being added. After being heated to about 25°C (the first set temperature), the air is sent to the drying chamber 1 by the fan of the first fresh air device 2. Another 50% of the fresh air is filtered and pressurized by the second fresh air device 9 and then sent to the heat exchanger 7. In the heat exchanger 7, the air is heated to about 80°C (the second set temperature in this embodiment is 80°C, the same below) and then sent to the drying chamber 1 through the third air valve 14. The hot air circulation unit 3 draws air from the drying chamber 1 and heats it to about 100°C before sending it to the drying chamber 1. The exhaust fan 5 draws exhaust air from the drying chamber 1 and sends it to the waste gas incineration device 4 for treatment. After treatment, the exhaust air is drawn to the heat exchanger 7 by the flue gas induced draft fan 8 to release heat and then discharged into the outdoor atmosphere through the chimney 6.

[0054] When the temperature and humidity sensor 16 detects that the outdoor air moisture content is less than 15g / kg and the flue gas temperature sensor 10 detects that the exhaust gas temperature is higher than 120℃, the first air valve 12, the second air valve 13, and the third air valve 14 are opened, the first fresh air device 2 and the fourth air valve 15 are closed, and the hot air circulation unit 3, the waste gas incineration device 4, the exhaust fan 5, the flue gas induced draft fan 8, and the second fresh air device 9 are turned on. At this time, the outdoor fresh air is filtered and pressurized by the second fresh air device 9 and sent to the heat exchanger 7. After absorbing heat in the heat exchanger 7 and being heated to about 80℃, it is sent to the drying chamber 1 through the third air valve 14. The hot air circulation unit 3 draws air from the drying chamber 1 and heats it to about 100℃ before sending it to the drying chamber 1. The exhaust fan 5 draws exhaust air from the drying chamber 1 and sends it to the waste gas incineration device 4 for treatment. After being drawn by the flue gas induced draft fan 8 to the heat exchanger 7 to release heat, it is discharged into the outdoor atmosphere through the chimney 6.

[0055] This embodiment sets three working modes. In the first working mode, only the first fresh air device is turned on. In the second working mode, both fresh air devices are turned on and the ratio of their fresh air volume is adjustable. In the third working mode, only the second fresh air device is turned on. The mode is switched according to the outdoor air humidity and flue gas temperature through the control system. Different working modes are adopted in different working environments, which not only makes the system flexible, but also enables the system to maximize the reduction of energy consumption.

[0056] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. An energy saving system for circulating air in a drying chamber, characterized in that, It comprises: a drying chamber; a temperature and humidity sensor for detecting the moisture content of outdoor air; a first fresh air device connected to the drying chamber and used to provide dehumidified and heated fresh air to the drying chamber; a hot air circulating unit connected to the drying chamber to form a circulation for heating the air in the drying chamber; a waste gas incineration device with its inlet connected to the drying chamber and its outlet connected to a chimney through an exhaust gas pipeline, and a flue gas temperature sensor arranged on the exhaust gas pipeline; a second fresh air device connected to the drying chamber and provided with a heat exchanger between the exhaust gas pipeline to heat the fresh air entering the drying chamber.

2. An energy efficient system for circulating air in a drying chamber as claimed in claim 1 wherein, The first fresh air device and the second fresh air device are both provided with air valves on the pipeline connected to the drying chamber.

3. A system for circulating air in a drying chamber according to claim 1, wherein The heat exchanger is provided with a fresh air temperature sensor on the pipeline connected to the drying chamber.

4. A system for circulating air in a drying chamber according to claim 1, wherein The waste gas incineration device is provided with an exhaust fan between the drying chamber.

5. A system for circulating air in a drying chamber according to claim 1, wherein The exhaust gas pipeline is provided with air valves on the pipeline connected to the heat exchanger.

6. An energy efficient system for circulating air in a drying chamber as claimed in claim 1 wherein, The exhaust gas pipeline is provided with a flue gas induced draft fan between the exhaust gas pipeline and the heat exchanger.

7. A system for circulating air in a drying chamber according to claim 1, wherein The first fresh air device is an air handling unit.

8. A system for circulating air in a drying chamber according to claim 1, wherein The second fresh air device is a fresh air fan box.

9. A system for circulating air in a drying chamber according to claim 1, wherein It further comprises a control system connected to the drying chamber, the first fresh air device, the hot air circulating unit, the second fresh air device, the waste gas incineration device, the temperature and humidity sensor, and the flue gas temperature sensor in a communication manner.

10. The method of operating an energy efficient system for circulating air in a drying chamber according to any one of claims 1-9, wherein, It comprises the following steps: Obtain the moisture content of outdoor air, and open the drying chamber, the hot air circulating unit, and the waste gas incineration device, and automatically switch the working mode by the control system according to the operating conditions; When the moisture content of outdoor air is greater than the first threshold value, only the first fresh air device is opened, and the outdoor fresh air is first cooled and dehumidified by the first fresh air device, then heated to the first set temperature, and then sent to the drying chamber; When the moisture content of outdoor air is greater than the second threshold value and less than the first threshold value, and the exhaust gas temperature is higher than the temperature threshold value, the first fresh air device and the second fresh air device are both opened, a certain proportion of outdoor fresh air is first cooled and dehumidified by the first fresh air device, then heated to the set temperature, and then sent to the drying chamber, and the remaining proportion of outdoor fresh air is sent to the heat exchanger through the second fresh air device to be heated to the second set temperature, and then sent to the drying chamber; When the moisture content of outdoor air is less than the second threshold value, and the exhaust gas temperature is higher than the temperature threshold value, only the second fresh air device is opened, and the outdoor fresh air is sent to the heat exchanger through the second fresh air device to be heated to the second set temperature, and then sent to the drying chamber.

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