Air handling system for a ship painting plant with return air

Abstract

The application relates to a ship painting workshop air treatment system with return air, comprising an air treatment module, a zeolite rotary wheel adsorption module and an RTO module; the input end of the air treatment module is connected with the output end of the zeolite rotary wheel adsorption module, the output end of the air treatment module is connected with a ship painting workshop air inlet, and the air outlet of the ship painting workshop is connected with the input end of the zeolite rotary wheel adsorption module. Compared with the prior art, the application reduces the total energy consumption of the ship painting workshop, improves the economy and environmental protection under the conditions of meeting the air supply requirements of the ship painting workshop and the VOCs treatment requirements.

Description

Technical Field

[0001] The present invention relates to a painting shop ventilation system, in particular to an air treatment system with return air for a ship painting shop. Background Art

[0002] During the painting process of shipbuilding, it is necessary to maintain a certain temperature and humidity environment, and at the same time, it is necessary to control the VOCs emitted, which is costly and energy-intensive. In large painting workshops, the air volume is often 40,000m 3 / h or more, and this fresh air needs to undergo certain heat and humidity treatments to meet workshop requirements before it can be introduced. Therefore, systems using fresh air consume a lot of energy and are less economical. In closed-loop systems, return air contains toxic and hazardous gases such as VOCs, which cannot guarantee the health and safety of workshop workers. VOC emissions in ship paint shops are often treated through costly zeolite rotors and RTO systems.

[0003] To address the issues with fresh air systems and closed-loop systems, a recirculation system that introduces return air can be considered. This system, after being processed by an air conditioner, mixes the return air from the workshop with fresh air from outside in a certain proportion before being delivered to the workshop. This air conditioning system can reduce energy consumption, improve economic efficiency, and also meet workshop hygiene requirements. For example, a fresh air air conditioner for a paint shop, licensed under CN214148195 U, installs a HEPA filter in the air intake chamber to effectively filter pollutants such as smoke, dust, and bacteria, purifying the air and removing particulate impurities contained in the return air to ensure its cleanliness. The return air is then treated by air temperature and humidity control equipment before being delivered to the automotive paint shop, achieving indoor air recycling and reducing workshop energy consumption. However, when this system is used in a ship paint shop, since the shop generates a large amount of VOCs, which are directly returned to the air, the filter cannot effectively absorb and treat them, causing pollution to the workshop environment and affecting personnel work.

[0004] In order to solve the problem of high cost of zeolite rotor and RTO system for VOCs treatment, it is possible to consider adopting different system operation modes according to the concentration of VOCs to improve economic efficiency. For example, a variable concentration VOCs treatment system based on zeolite rotor catalytic oxidation authorized by CN 216964074 U has two operating modes: normal mode and low concentration mode, and includes two subsystems: adsorption system and desorption system. The switching of different modes is achieved by switching the valve. When the adsorption system and the desorption system are working at the same time, the variable concentration VOCs treatment system enters the normal mode. When the adsorption system is working and the desorption system is not working, the variable concentration VOCs treatment system enters the low concentration mode. In this way, the operating time of the catalytic combustion device and the heating device under low concentration conditions can be reduced, thereby reducing the energy consumption of the system operation. Although this system reduces the energy consumption of the VOCs treatment system, it cannot solve the problem of high cost and high energy consumption of fresh air in the paint shop. Summary of the Invention

[0005] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and provide an air treatment system for a ship painting workshop with return air, thereby reducing the total energy consumption of the ship painting workshop and improving economy and environmental protection while meeting the air supply requirements and VOCs control requirements of the ship painting workshop.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] The present invention provides an air treatment system for a ship painting workshop with return air, comprising an air treatment module, a zeolite rotor adsorption module, and an RTO module;

[0008] The input end of the air treatment module is connected to the output end of the zeolite wheel adsorption module, and the output end of the air treatment module is connected to the air inlet of the ship painting workshop;

[0009] The exhaust port of the ship painting workshop is connected to the input end of the zeolite wheel adsorption module.

[0010] As an embodiment of the present invention, the zeolite rotor adsorption module is a double-stage zeolite rotor adsorption structure;

[0011] The zeolite rotor adsorption module includes a first-stage zeolite concentration rotor and a second-stage zeolite concentration rotor connected in series.

[0012] Furthermore, the air processing module includes an air handling unit, an air mixing chamber provided at an input end of the air handling unit, a fresh air damper and a secondary return air damper respectively connected to the air mixing chamber, and an air supply fan provided at an output end of the air handling unit.

[0013] Furthermore, the zeolite concentration wheel is composed of an adsorption zone and a desorption zone. The wheel material used can efficiently adsorb VOC gas molecules emitted by paint at room temperature and can desorb VOC gas molecules at high temperature.

[0014] Preferably, the secondary zeolite wheel has a targeted adsorption characteristic for VOC gas molecules emitted by specific paints, and can efficiently adsorb and desorb VOC gas molecules emitted by specific paints.

[0015] Furthermore, the air inlet damper is arranged at the entrance of the air inlet duct, and the air mixing chamber, air handling unit, and air supply fan are arranged in sequence along the air supply flow direction. The air supply fan is connected to the air supply duct, driving the air to be sent into the painting workshop after heat and humidity treatment by the air handling unit.

[0016] The air handling unit may be a device for regulating air temperature and humidity, including a combined air conditioning box, a combined rotary dehumidifier, a heat pump type air temperature and humidity regulating unit, and the like.

[0017] Furthermore, bypass air passages are connected in parallel at both ends of the first-stage zeolite concentration rotor;

[0018] The inlet of the bypass air passage and the inlet of the adsorption zone of the first-stage zeolite concentration rotor are respectively provided with a bypass air damper and an adsorption air damper. The inlet of the bypass air passage and the inlet of the adsorption zone of the first-stage zeolite concentration rotor are connected, and a main fan is provided at the connection;

[0019] The outlet of the bypass air passage is connected to the outlet of the adsorption zone of the first-stage zeolite concentration wheel, and a first-stage adsorption fan is provided at the connection.

[0020] Furthermore, an air filter is connected to the inlet side of the main fan, and the input end of the air filter is connected to the air outlet of the ship painting workshop;

[0021] A first-stage desorption fan is connected to the outlet of the desorption zone of the first-stage zeolite concentration wheel, and the output end of the first-stage desorption fan is connected to the RTO module.

[0022] Furthermore, a first-level return air damper is connected to the input port of the adsorption zone of the secondary zeolite concentration wheel, and a first-level exhaust air damper is provided on the pipeline between the first-level return air damper and the first-level adsorption fan;

[0023] A secondary adsorption fan is connected to the output port of the adsorption zone of the secondary zeolite concentration wheel, and the secondary adsorption fan is connected to the secondary return air damper;

[0024] A secondary desorption fan is connected to the output port of the adsorption zone of the secondary zeolite concentration wheel, and the secondary desorption fan is connected to the RTO module.

[0025] Furthermore, the paint shop's exhaust vent is connected to an air filter, which is driven by a main fan into the air supply duct in front of the primary zeolite concentrator. The primary zeolite concentrator is connected to a bypass duct, and the air flow path is changed by adjusting the adsorption damper and bypass damper. The adsorption zone of the primary zeolite concentrator is connected to a primary adsorption fan, which drives air into the air supply duct. The desorption zone of the primary zeolite concentrator is connected to a primary desorption fan, which drives the concentrated VOC air into the RTO module for combustion control.

[0026] Furthermore, the air driven by the first-level adsorption fan enters the air supply channel, and a part of the air is sent to the second-level zeolite concentration wheel through the adjustment of the first-level return air damper and the first-level exhaust air damper. The adsorption area of ​​the second-level zeolite concentration wheel is connected to the second-level adsorption fan, and the air is driven into the return air channel by the second-level adsorption fan. The desorption area of ​​the second-level zeolite concentration wheel is connected to the second-level desorption fan, and the concentrated VOC air is driven into the RTO module for combustion control by the second-level desorption fan.

[0027] Furthermore, the secondary adsorption fan drives the air through the return air channel, and through the adjustment of the return air damper, enters the air mixing chamber and mixes with the fresh air, forming a return air recycling system with a double-stage zeolite rotor.

[0028] Furthermore, when the VOCs output from the ship paint shop are at high concentrations, the primary zeolite concentration rotor and the secondary zeolite concentration rotor simultaneously perform continuous adsorption and desorption work;

[0029] When the concentration of VOCs is at medium or low levels, the first-level zeolite concentration rotor and the second-level zeolite concentration rotor enter intermittent working state as appropriate, wherein: the adsorption zones of the two zeolite rotors maintain continuous operation, and when the cumulative concentration of VOCs in the desorption zones of the two zeolite rotors exceeds the preset threshold and lasts for the preset time, the first-level zeolite concentration rotor and the second-level zeolite concentration rotor perform desorption work, desorbing the concentrated VOCs air into the RTO module for centralized combustion treatment.

[0030] As another embodiment of the present invention, the zeolite rotor adsorption module is a single-stage zeolite rotor adsorption structure;

[0031] The air handling module includes an air handling unit, an air mixing chamber provided at the input end of the air handling unit, a fresh air damper and a return air damper respectively connected to the air mixing chamber, and an air supply fan provided at the output end of the air handling unit;

[0032] The zeolite rotor adsorption module includes a zeolite concentration rotor.

[0033] The air handling unit may be a device for regulating air temperature and humidity, including a combined air conditioning box, a combined rotary dehumidifier, a heat pump type air temperature and humidity regulating unit, and the like.

[0034] Furthermore, the output end of the adsorption zone of the zeolite concentration wheel is connected to an adsorption fan, the output end of the adsorption fan is connected to the return air damper through a pipeline, and an exhaust damper is provided on the pipeline at the connection;

[0035] The input end of the zeolite concentration wheel adsorption zone is connected to a main fan, the input end of the main fan is connected to an air filter, and the air filter is connected to the exhaust port of the coating workshop;

[0036] The zeolite concentration wheel desorption zone is connected to a desorption fan, and the desorption fan is connected to the RTO module.

[0037] Furthermore, the zeolite concentration wheel is composed of an adsorption zone and a desorption zone. The wheel material used can efficiently adsorb VOC gas molecules emitted by paint at room temperature and can desorb VOC gas molecules at high temperature.

[0038] Furthermore, the air inlet damper is arranged at the inlet of the air inlet duct, the air mixing chamber, air handling unit and air supply fan are arranged in sequence along the air supply flow direction, and the air supply fan is connected to the air supply duct to drive the air into the painting workshop after heat and humidity treatment.

[0039] Furthermore, the exhaust port of the painting workshop is connected to the air filter, and the indoor exhaust air is driven into the zeolite concentration wheel through the main fan. The adsorption zone of the zeolite concentration wheel is connected to the adsorption fan, and the air is driven into the return air channel through the adsorption fan. The desorption zone of the zeolite concentration wheel is connected to the desorption fan, and the desorption fan drives the zeolite wheel desorption zone to desorb and send the concentrated VOC air into the RTO module for combustion control.

[0040] Furthermore, the air driven by the adsorption fan is used as return air, and the return air and exhaust air ratio is adjusted by adjusting the return air damper and the exhaust damper. The return air enters the air mixing chamber and is mixed with the fresh air to form a return air recycling system with a single-stage zeolite rotor.

[0041] Furthermore, when the VOCs output from the ship paint shop are at high concentrations, the zeolite concentrator wheel performs continuous adsorption and desorption simultaneously;

[0042] When the concentration of VOCs is at medium or low levels, the zeolite concentration wheel will enter an intermittent working state depending on the situation, in which: the adsorption zone of the zeolite wheel maintains continuous operation, and when the cumulative concentration of VOCs in the desorption zone of the zeolite wheel exceeds the preset threshold and lasts for the preset time, the zeolite concentration wheel performs desorption work, desorbing the concentrated VOCs air into the RTO module for centralized combustion treatment.

[0043] The environmentally friendly and energy-saving air treatment system for a ship painting workshop with return air and double-stage zeolite wheel adsorption is suitable for ensuring the normal operation of an air dehumidification module, with high return air cleanliness and a return air VOCs concentration requirement that is higher than the exhaust air standard, including a high-concentration VOCs operation mode, a medium-concentration VOCs operation mode, and a low-concentration VOCs mode.

[0044] High-concentration VOCs operation mode: The supply fan of the environmentally friendly and energy-saving air treatment system of the ship painting workshop with return air adsorption with the two-stage zeolite rotor is turned on, driving the air to pass through the air handling unit in turn to be processed to the required temperature and humidity, and then sucked into the air supply duct through the supply fan and sent to the workshop. The main fan drives the workshop exhaust air into the air filter, closes the bypass damper, opens the adsorption damper, and the exhaust air enters the first-stage zeolite concentration rotor after filtration. Turn on the first-stage adsorption fan and the first-stage desorption fan. The first-stage desorption fan drives the concentrated VOC air into the RTO module for VOCs treatment, and the first-stage adsorption fan drives the air after preliminary adsorption into the air duct. At this time, the air volume can be adjusted through the first-stage exhaust damper and the first-stage return air damper. Adjust the damper according to the return air volume to discharge part of the air, and the remaining preliminary clean air is further sent to the second-stage concentration zeolite rotor. At this time, the VOCs concentration is still high and requires further adsorption treatment. Turn on the secondary adsorption fan and the secondary desorption fan. The secondary desorption fan sends the concentrated VOC air into the RTO module for VOCs treatment. The secondary adsorption fan sends the clean air into the return air duct, enters the air mixing chamber through the secondary return air damper, and then is driven by the supply fan to complete the return air recycling.

[0045] Medium-concentration VOCs operation mode: The air treatment module steps for the medium-concentration VOCs operation mode are the same as those for the high-concentration VOCs operation mode. The difference lies in the zeolite rotor adsorption module. After the main fan is turned on, the exhaust air in the workshop enters the air filter for filtration. The bypass damper is closed, and the adsorption damper is opened. The filtered exhaust air enters the first-stage zeolite concentrating rotor. The first-stage adsorption fan and the first-stage desorption fan are turned on. The first-stage desorption fan sends the concentrated VOC air to the RTO module for VOCs treatment. The first-stage desorption fan sends the preliminarily clean air into the supply air duct. Through the first-stage exhaust damper and the first-stage return air damper, some air is directly discharged, and the rest is sent to the second-stage zeolite concentrating rotor. At this point, the VOC concentration of the air after adsorption in the adsorption zone is further reduced, meeting the air supply requirements. The adsorption fan is turned on, and the air is sent into the air mixing chamber through the second-stage return air damper. After mixing with the fresh air, it is pulled by the supply air fan to complete the return air recirculation. Since the VOCs concentration is low, in order to save energy, the secondary desorption fan can be turned off to allow VOCs to gradually accumulate on the secondary zeolite concentration rotor. The frequency of use of the secondary desorption fan is controlled: when it is detected that the VOCs concentration of the rotor outlet air exceeds the limit and reaches the standard for starting the desorption device, the secondary desorption fan is started to allow VOCs to separate from the desorption area and enter the RTO module for centralized combustion treatment. When it is detected that the VOCs concentration of the secondary zeolite concentration rotor outlet air is low, the secondary desorption fan stops running to save electricity, and the RTO module stops running to save natural gas.

[0046] Low-concentration VOCs operation mode: The operation steps of the low-concentration VOCs operation mode in the air treatment module are the same as those of the high-concentration and medium-concentration VOCs operation modes. The difference lies in the zeolite rotor adsorption module. When the main fan is turned on, the exhaust air from the workshop first enters the air filter. If the exhaust air from the workshop needs to be partially discharged, in order to ensure that the exhausted air needs to undergo at least one level of treatment, the bypass damper is closed and the adsorption damper is opened. The filtered air enters the first-level zeolite concentration rotor. Due to the low VOCs concentration, in order to save energy, the first-level desorption fan can be turned off to allow VOCs to gradually accumulate on the first-level zeolite concentration rotor. The frequency of use of the first-level desorption fan is controlled: when the VOCs concentration of the rotor outlet air exceeds the limit and reaches the standard for starting the desorption device, the first-level desorption fan is started to separate the VOC from the desorption area and enter the RTO module for centralized combustion treatment. When the VOCs concentration of the first-level zeolite concentration rotor outlet is detected to be low, the first-level desorption fan is stopped to save electricity, and the RTO module is shut down to save natural gas. The first-stage adsorption fan is turned on, and the initially cleaned air is drawn forward by the adsorption fan. After adjustment by the first-stage exhaust damper and the first-stage return air damper, some of the air is directly discharged, while the remaining air is sent to the second-stage zeolite concentrating rotor. To save some fan energy, if all the workshop's exhaust air is used as return air and not exhausted outdoors, the adsorption damper is closed and the bypass damper is opened. Driven by the first-stage adsorption fan, the exhaust air enters the bypass duct directly and is conveyed forward. The first-stage exhaust damper is closed and the first-stage return air damper is opened, and all the exhaust air is sent to the second-stage zeolite concentrating rotor. The second-stage adsorption fan is turned on, and it draws the air through the second-stage return air damper into the air mixing chamber. After mixing with the fresh air, it is drawn by the supply air fan, completing the recirculation of the return air. Since the VOCs concentration is low, in order to save energy, the secondary desorption fan can be turned off to allow VOCs to gradually accumulate on the secondary zeolite concentration rotor. The frequency of use of the secondary desorption fan is controlled: when it is detected that the VOCs concentration of the rotor outlet air exceeds the limit and reaches the standard for starting the desorption device, the secondary desorption fan is started to allow VOCs to separate from the desorption area and enter the RTO module for centralized combustion treatment. When it is detected that the VOCs concentration of the secondary zeolite concentration rotor outlet air is low, the secondary desorption fan stops running to save electricity, and the RTO module stops running to save natural gas.

[0047] The environmentally friendly and energy-saving air treatment system for a ship painting workshop with return air and single-stage zeolite rotor adsorption is suitable for a system in which the VOC treatment efficiency of the single-stage rotor is sufficient, there is almost no VOC leakage from the rotor, and the return air meets the requirements, and includes a high-concentration VOCs operation mode and a low-concentration VOCs mode.

[0048] High-concentration VOCs operation mode: The supply fan of the environmentally friendly and energy-saving air treatment system of the ship painting workshop with return air adsorption with the single-stage zeolite rotor is turned on, driving the air to flow through the air handling unit in turn and be processed to the required temperature and humidity. The air is then sucked into the supply air duct through the supply fan and sent into the painting workshop. The main fan is turned on to drive the exhaust air in the workshop to enter the air filter for preliminary filtration, and then enter the zeolite concentration rotor. When it is detected that the exhaust VOCs concentration is high, the adsorption fan and the desorption fan are turned on at the same time. The desorption fan drives the concentrated VOC air into the RTO module to treat the VOCs, and the adsorption fan drives the clean air after adsorption into the return air duct. The fresh air ratio is adjusted by adjusting the return air damper, the fresh air damper and the exhaust damper. The return air enters the air mixing chamber and is mixed with the fresh air. It is then driven by the supply air fan to complete a return air recirculation.

[0049] The damper can be opened freely. When the demand for fresh air is low, such as when there are fewer people or at night, the fresh air damper can be appropriately closed and the return air damper can be opened at the entrance to adjust the fresh air volume.

[0050] Low-concentration VOCs operation mode: The supply air fan of the environmentally friendly and energy-saving air treatment system of the ship painting workshop with return air adsorption of the single-stage zeolite rotor is turned on, driving the air to flow through the air cooler and dehumidification rotor in sequence. After being treated to the required temperature and humidity, it is sucked into the air supply channel through the supply air fan and sent into the painting workshop. The main fan is turned on to drive the exhaust air in the workshop to enter the air filter for filtration first, and then enter the zeolite concentration rotor. When it is detected that the exhaust VOCs concentration is low, in order to save energy, the desorption fan can be turned off to allow VOCs to gradually accumulate on the zeolite concentration rotor. The frequency of use of the desorption fan is controlled: when it is detected that the VOCs concentration of the rotor outlet air exceeds the limit and reaches the standard for starting the desorption device, the desorption fan is started to separate the VOC from the desorption area and enter the RTO module for centralized combustion treatment. When it is detected that the VOCs concentration of the zeolite concentration rotor outlet air is low, the desorption fan stops running to save electricity, and the RTO module stops the furnace to save natural gas. Turn on the adsorption fan, which drives the clean air after adsorption into the return air duct. The fresh air ratio is adjusted by adjusting the return air damper, fresh air damper and exhaust damper. The return air then enters the air mixing chamber and mixes with the fresh air. The return air is then driven by the supply air fan to complete the recycling of the return air. Control the applicable frequency of the desorption fan. When the VOCs concentration in the desorption zone reaches the desorption standard, turn on the desorption fan to drive the desorption process in the zeolite rotor desorption zone and send the VOC concentrated air into the RTO module for combustion control. Similarly, the damper can be adjusted freely. When the demand for fresh air is low, the fresh air damper can be closed and the return air damper can be opened to adjust the fresh air volume.

[0051] Compared with the prior art, the present invention has the following beneficial effects:

[0052] 1. The present invention reduces the energy consumption of the air dehumidification module by introducing the exhaust air from the paint shop into the air dehumidification module as return air after the VOCs are removed by adsorption on the zeolite rotor. The existing air dehumidification module in the paint shop adopts a fresh air mode, and the heat and moisture load of the fresh air is generally high. Therefore, the heat and moisture treatment energy consumption of the fresh air system is very large and the economy is poor. In the present invention, the clean air after the VOCs are removed by adsorption on the zeolite rotor is introduced into the return air channel for reuse, thereby reducing the proportion of fresh air. Since the temperature and humidity of the indoor return air are closer to the supply air state than the fresh air, the introduction of the return air can reduce the size of the heat and moisture load handled by the air dehumidification module, thereby effectively reducing the energy consumption of the air dehumidification module and improving the economy of the entire system while meeting the supply air requirements.

[0053] 2. The present invention provides system control modes tailored to the VOC concentrations in the exhaust air, enabling treatment based on time periods and VOC concentrations. This reduces the gas consumption of the RTO equipment during VOC exhaust treatment and reduces the energy consumption of the desorption blower. The VOC emission intensity in a ship paint shop is a continuously changing process, with the VOC concentration in the air generally experiencing three phases: a rapid rise, a rapid fall, and a slow fall. When VOC concentrations are high, all zeolite rotors in the system simultaneously perform continuous adsorption and desorption operations. When VOC concentrations are low or medium, some or all of the zeolite rotors in the system can enter intermittent operation, depending on the situation. Specifically, the adsorption zone of the zeolite rotor remains in continuous operation, while the desorption zone only periodically performs desorption when the cumulative VOC concentration in the rotor is high, desorbing the concentrated VOC air into the RTO module for centralized combustion treatment. Desorption is not performed during other time periods (RTO shutdown). Accordingly, the desorption blowers associated with the zeolite rotors can be controlled to start and stop according to the operating conditions of the desorption zone. Through the intermittent operation of the zeolite rotor desorption fan and the RTO equipment, the energy consumption of the RTO equipment in the system when treating VOCs in the exhaust gas can be effectively reduced, thereby saving the use of gas; in addition, the operating energy consumption of the desorption fan is also reduced due to intermittent operation.

[0054] 3. By installing fresh air dampers, return air dampers, and exhaust dampers in the air supply duct, this invention can meet the demand for fresh air volume under different operating conditions. Since fresh air processing consumes a lot of energy, when the fresh air demand is low, that is, when the VOC concentration is low, or when there are no people at night, the fresh air dampers can be appropriately closed to reduce the energy consumption of the equipment's fresh air heat and moisture treatment.

[0055] 4. This invention provides a technical solution with return air and dual-stage zeolite rotor adsorption. This solution uses a primary zeolite concentrator to adsorb a broad spectrum of VOC molecules, and a secondary zeolite concentrator made of targeted adsorption material to efficiently adsorb VOC molecules emitted by specific paints, thereby ensuring the cleanliness of the return air and protecting the air handling heat exchanger from contamination. A bypass duct, equipped with bypass dampers and adsorption dampers, is installed in the ventilation system. When the workshop exhaust VOC concentration is low and all exhaust air is used as return air, the air bypasses the primary concentrator, saving fan power. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 This is a schematic diagram of the principle of the environmentally friendly and energy-saving air treatment system for ship painting workshops with return air using the double-stage zeolite rotor adsorption of the present invention.

[0057] Figure 2 This is a schematic diagram of the principle of the environmentally friendly and energy-saving air treatment system for a ship painting workshop with return air using a single-stage zeolite rotor adsorption system according to the present invention.

[0058] Figure 1 In: 1. Fresh air damper, 2. Air mixing chamber, 3. Air handling unit, 4. Supply air fan, 5. Painting workshop, 6. Air filter, 7. Main fan, 8. Bypass damper, 9. Adsorption damper, 10. First-stage zeolite concentration rotor, 11. First-stage adsorption fan, 12. First-stage exhaust damper, 13. First-stage return air damper, 14. Second-stage zeolite concentration rotor, 15. Second-stage adsorption fan, 16. Second-stage return air damper, 17. Second-stage desorption fan, 18. RTO module, 19. First-stage desorption fan.

[0059] Figure 2 Middle: 1′, fresh air damper, 2′, air mixing chamber, 3′, air handling unit, 4′, supply air fan, 5′, paint shop, 6′, air filter, 7′, main fan, 8′, zeolite concentration rotor, 9′, adsorption fan, 10′, exhaust damper, 11′, return air damper, 12′, desorption fan, 13′, RTO module. DETAILED DESCRIPTION

[0060] The air treatment system of the ship painting workshop with return air in the present invention includes an air treatment module, a zeolite rotor adsorption module, and an RTO module; the input end of the air treatment module is connected to the output end of the zeolite rotor adsorption module, and the output end of the air treatment module is connected to the air inlet of the ship painting workshop; the exhaust port of the ship painting workshop is connected to the input end of the zeolite rotor adsorption module.

[0061] When the adsorption module adopts a dual-stage zeolite rotor adsorption structure, the zeolite rotor adsorption module includes a first-stage zeolite concentrating rotor and a second-stage zeolite concentrating rotor connected in series. The air handling module includes an air handling unit, an air mixing chamber located at the input end of the air handling unit, a fresh air damper and a second-stage return air damper connected to the air mixing chamber, and a supply air fan located at the output end of the air handling unit.

[0062] The zeolite concentrator rotor consists of an adsorption zone and a desorption zone. The rotor material used efficiently adsorbs VOC gas molecules emitted by paint at room temperature and desorbs them at elevated temperatures. The secondary zeolite rotor has targeted adsorption properties for VOC gas molecules emitted by specific paints, effectively adsorbing and desorbing them. An inlet damper is located at the inlet of the air inlet duct. An air mixing chamber, air handling unit, and supply fan are arranged sequentially along the air flow direction. The supply fan is connected to the air duct, driving air through the air handling unit for heat and moisture treatment before delivery to the paint shop. A bypass airway is connected in parallel at both ends of the zeolite concentrator rotor. A bypass damper and an adsorption damper are respectively installed at the inlet of the bypass airway and the inlet of the adsorption zone of the primary zeolite concentrator rotor. The bypass airway inlet is connected to the inlet of the adsorption zone of the primary zeolite concentrator rotor, with a main fan located at the junction. The outlet of the bypass airway is connected to the outlet of the adsorption zone of the primary zeolite concentrator rotor, with a primary adsorption fan located at the junction.

[0063] An air filter is connected to the inlet side of the main fan, and the input end of the air filter is connected to the air outlet of the ship coating workshop; a first-level desorption fan is connected to the outlet of the desorption zone of the first-level zeolite concentration rotor, and the output end of the first-level desorption fan is connected to the RTO module. A first-level return air damper is connected to the input of the adsorption zone of the second-level zeolite concentration rotor, and a first-level exhaust damper is installed on the pipeline between the first-level return air damper and the first-level adsorption fan; a second-level adsorption fan is connected to the output of the adsorption zone of the second-level zeolite concentration rotor, and the second-level adsorption fan is connected to the second-level return air damper; a second-level desorption fan is connected to the output of the adsorption zone of the second-level zeolite concentration rotor, and the second-level desorption fan is connected to the RTO module.

[0064] The paint shop's exhaust vent is connected to an air filter, which is then driven by a main fan into the air supply duct in front of the primary zeolite concentrator. The primary zeolite concentrator is connected to a bypass duct, and the air flow path is changed by adjusting the adsorption damper and bypass damper. The adsorption zone of the primary zeolite concentrator is connected to the primary adsorption fan, which drives air into the air supply duct. The desorption zone of the primary zeolite concentrator is connected to the primary desorption fan, which drives the concentrated VOC air into the RTO module for combustion control.

[0065] Air driven by the primary adsorption fan enters the air supply duct. Through the adjustment of the primary return air damper and the primary exhaust damper, a portion of the air is sent to the secondary zeolite concentration rotor. The adsorption zone of the secondary zeolite concentration rotor is connected to the secondary adsorption fan, which drives the air into the return air duct. The desorption zone of the secondary zeolite concentration rotor is connected to the secondary desorption fan, which drives the concentrated VOC air into the RTO module for combustion control. The secondary adsorption fan drives the air through the return air duct. Through the adjustment of the return air damper, it enters the air mixing chamber and mixes with the fresh air, forming the primary return air recirculation of the double-stage zeolite rotor with return air system.

[0066] When the zeolite rotor adsorption module is a single-stage zeolite rotor adsorption structure, the air handling module includes an air handling unit (AHU), an air mixing chamber located at the AHU input, a fresh air damper and a return air damper connected to the air mixing chamber, and a supply air fan located at the AHU output. The zeolite rotor adsorption module includes a zeolite concentrating rotor. The AHU can utilize equipment such as a modular air conditioning unit, a modular rotor dehumidifier, or a heat pump air temperature and humidity control unit to regulate air temperature and humidity.

[0067] The adsorption zone output of the zeolite concentrating rotor is connected to an adsorption fan, which is connected to the return air damper via a pipeline. An exhaust damper is also installed on the pipeline at this connection. The adsorption zone input of the zeolite concentrating rotor is connected to a main fan, which is connected to an air filter, which is connected to the paint shop's exhaust port. The desorption zone of the zeolite concentrating rotor is connected to a desorption fan, which is connected to the RTO module. The zeolite concentrating rotor consists of an adsorption zone and a desorption zone. The rotor material used can efficiently adsorb VOC gas molecules emitted by paint at room temperature and desorb VOC gas molecules at high temperatures.

[0068] The air inlet damper is arranged at the entrance of the air inlet duct. The air mixing chamber, air handling unit and air supply fan are arranged in sequence along the air supply flow direction. The air supply fan is connected to the air supply duct to drive the air into the painting workshop after heat and humidity treatment.

[0069] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. Component models, material names, connection structures, control methods, algorithms, and other features not explicitly described in this technical solution are considered common technical features disclosed in the prior art.

[0070] Example 1

[0071] This embodiment is an environmentally friendly and energy-saving air treatment system for ship painting workshops with return air and double-stage zeolite wheel adsorption, which is suitable for ensuring the normal operation of the air dehumidification module, high return air cleanliness, and a system with a return air VOCs concentration requirement higher than the exhaust air standard. Figure 1As shown, it consists of an air treatment module, a paint shop, a zeolite wheel adsorption module and an RTO module.

[0072] The RTO module, also known as the RTO combustion system, is used to treat organic waste gas. It is suitable for applications where exhaust gas composition frequently changes or concentrations fluctuate significantly across a single production line due to product diversity. Applications include exhaust gas treatment in coating lines in automotive, motorcycle, shipbuilding, bicycle, home appliance, and container plants, as well as in petrochemical, rubber, coatings, viscose, printing, and enameled wire production lines. It is particularly suitable for businesses requiring heat recovery or for treating exhaust gas from drying lines, where energy can be recycled back into the drying line, thereby conserving energy. The principle is that combustible organic waste gas undergoes thermal oxidation at temperatures between 760 and 1000 degrees Celsius, producing carbon dioxide and water. The waste gas is first heated to near the thermal oxidation temperature by a heat storage medium before entering a combustion chamber for thermal oxidation. The resulting gas temperature rises, converting organic matter primarily into carbon dioxide and water. The purified gas then passes through another heat storage medium, cooling its temperature until it meets national emission standards before being discharged.

[0073] The air handling module includes a fresh air damper 1, an air mixing chamber 2, an air handling unit 3, a supply air blower 4, and a return air damper 16. The air mixing chamber 2, the air handling unit 3, and the supply air blower 4 are arranged in sequence along the air flow direction. The supply air blower 4 is connected to the air supply duct, driving the air to be heated and humidified before being delivered to the paint shop 5.

[0074] The supply blower 4 drives air into the paint shop 5. The main blower 7 of the zeolite rotor adsorption module drives the exhaust air from the workshop into an air filter 6 containing multiple stages of filter elements with different efficiencies for filtration. The air filter 6 can be any commercially available air filter assembly. The air flow path is determined by the opening status of the bypass damper 8 and the adsorption damper 9. If the bypass damper 8 is open and the adsorption damper 9 is closed, the air filtered by the air filter 6 enters the bypass air duct through the bypass damper 8 and is then driven by the first-stage adsorption blower 11 to enter the return air duct between the first-stage zeolite concentration rotor 10 and the second-stage zeolite concentration rotor 14. If the bypass damper 8 is closed and the adsorption damper 9 is open, the first-stage adsorption blower 11 connects to the adsorption zone of the first-stage zeolite concentration rotor 10 and drives the clean air in the adsorption zone into the return air duct between the first-stage zeolite concentration rotor 10 and the second-stage zeolite concentration rotor 14. The first-stage desorption blower 19 connects to the desorption zone of the first-stage zeolite concentration rotor 10 and drives the VOC-concentrated air in the desorption zone into the RTO module 18 for VOCs treatment.

[0075] The return air passages of the two zeolite concentrating wheels include a first-stage exhaust damper 12 and a first-stage return air damper 13 for adjusting the return air and exhaust air volumes.

[0076] The secondary adsorption fan 15 drives the return air into the secondary zeolite concentrating rotor 14, driving the further purified air after adsorption into the return air duct in front of the air mixing chamber 2. After being regulated by the secondary return air damper 16, it enters the air mixing chamber 2 and is then driven by the supply fan 5 to complete the circulation. The secondary desorption fan 19 drives the concentrated VOC air from the desorption zone of the secondary zeolite concentrating rotor 14 into the RTO module 18 for VOCs treatment.

[0077] In the system, the fresh air damper 1, the bypass damper 8, the adsorption damper 9, the first-level exhaust damper 12, the first-level return air damper 13, and the second-level return air damper 16 can all be opened and closed independently, and the supply air fan 4, the main fan 7, the first-level adsorption fan 11, the first-level desorption fan 19, the second-level adsorption fan 15, and the second-level desorption fan 17 can all be opened and closed independently, and the speed can be adjusted in stages.

[0078] The dual-stage zeolite rotor adsorption and return air environmentally friendly and energy-saving air treatment system for ship paint shops has three operating modes: high-concentration VOCs, medium-concentration VOCs, and low-concentration VOCs:

[0079] High-concentration VOCs mode: The supply air fan 4 is turned on, and the air is processed by the air treatment module to the required temperature and humidity state, and then enters the ship painting workshop 5 through the air supply duct. The main fan 7 is turned on, driving the workshop exhaust air to be filtered through the air filter 6. At this time, the bypass damper 8 is closed, the adsorption damper 9 is opened, and the air filtered by the air filter 6 enters the first-level zeolite concentration rotor 10. Due to the high VOCs concentration, the first-level adsorption fan 11 and the first-level desorption fan 19 are turned on at the same time. The first-level adsorption fan 11 drives the clean air in the adsorption zone of the first-level zeolite concentration rotor 10 into the return air duct between the two concentration rotors. Through the adjustment of the first-level exhaust damper 12 and the first-level return air damper 13, part of the air is discharged, and the other part of the air is driven by the second-level adsorption fan 15 and enters the second-level zeolite concentration rotor 14. The clean air after adsorption enters the return air duct again, and after adjustment by the second-level return air damper 16, it enters the air mixing chamber 2, and is then driven by the supply air fan 4 to complete the cycle. The secondary desorption fan 17 is turned on to drive the concentrated VOC air in the desorption zone of the secondary zeolite concentration wheel 14 into the RTO module 18 for VOCs treatment.

[0080] Medium-concentration VOCs mode: The supply air blower 4 is turned on, and air is processed by the air treatment module to the required temperature and humidity before entering the ship paint shop 5 through the supply air duct. The main air blower 7 is turned on, driving the workshop exhaust air through the air filter 6. At this time, the bypass damper 8 is closed, and the adsorption damper 9 is opened. The air filtered by the air filter 6 enters the first-stage zeolite concentrator 10. Due to the high VOC concentration, the first-stage adsorption fan 11 and the first-stage desorption fan 19 are turned on simultaneously. The first-stage adsorption fan 11 drives the clean air from the adsorption zone of the first-stage zeolite concentrator 10 into the return air duct between the two concentrators. At this point, the return air meets the exhaust requirements but does not meet the supply air VOC concentration requirements. Through the adjustment of the first-stage exhaust damper 12 and the first-stage return air damper 13, some air is discharged, and the remaining air is driven by the second-stage adsorption fan 15 and enters the second-stage zeolite concentrator 14. The clean air after adsorption enters the return air duct, and after adjustment by the second-stage return air damper 16, it enters the air mixing chamber 2 and is then driven by the supply air blower 4, completing the cycle. Since the VOCs concentration is low, in order to save energy, the secondary desorption fan 17 can be turned off to allow VOCs to gradually accumulate on the secondary zeolite concentration rotor 14. The frequency of use of the secondary desorption fan 17 is controlled: when it is detected that the VOCs concentration of the rotor outlet air exceeds the limit and reaches the standard for starting the desorption device, the secondary desorption fan 17 is started to allow VOCs to separate from the desorption area and enter the RTO module 18 for centralized combustion treatment. When it is detected that the VOCs concentration of the secondary zeolite concentration rotor 14 outlet air is low, the secondary desorption fan 17 stops running to save electricity, and the RTO module 18 stops running to save natural gas.

[0081] Low-concentration VOCs mode: The air supply fan 4 is turned on, and the air is processed by the air treatment module to the required temperature and humidity state, and then enters the ship painting workshop 5 through the air supply channel. The main fan 7 is turned on, driving the workshop exhaust air to pass through the air filter 6 for filtration. If the workshop exhaust air needs to be partially discharged, to ensure that the exhausted air needs to undergo at least one level of treatment, the bypass damper 8 is closed and the adsorption damper 9 is opened. The filtered air enters the first-level zeolite concentration rotor 10. Due to the low VOCs concentration, to save energy, the first-level desorption fan 19 can be turned off to allow VOCs to gradually accumulate on the first-level zeolite concentration rotor 10. The frequency of use of the first-level desorption fan 19 is controlled: when the VOCs concentration of the rotor outlet air exceeds the limit and reaches the standard for starting the desorption device, the first-level desorption fan 19 is started, allowing VOCs to be separated from the desorption zone and enter the RTO module 18 for centralized combustion treatment. When the VOCs concentration of the zeolite concentration rotor 10 outlet air is detected to be low, the desorption fan 19 is stopped to save electricity, and the RTO module 18 is shut down to save natural gas. The first-stage adsorption fan 11 is turned on, and the preliminarily cleaned air is pulled forward by the first-stage adsorption fan 11. After being adjusted by the first-stage exhaust damper 12 and the first-stage return air damper 13, part of the air is directly discharged, and the other part of the air is sent to the second-stage zeolite concentration rotor 14. If, in order to save some fan energy consumption, all the exhaust air in the workshop is used as return air and not exhausted to the outside, the adsorption damper 9 is closed and the bypass damper 8 is opened. Driven by the first-stage adsorption fan 11, the exhaust air directly enters the bypass air duct and is transported forward. The first-stage exhaust damper 12 is closed, and the first-stage return air damper 13 is opened, and all the exhaust air is sent to the second-stage zeolite concentration rotor 14. Driven by the second-stage adsorption fan 15, the air passes through the air mixing chamber 2 after adsorption by the second-stage zeolite concentration rotor 14, and is then driven by the supply fan 4 to complete the cycle. Since the VOCs concentration is low, in order to save energy, the secondary desorption fan 17 can be turned off to allow VOCs to gradually accumulate on the secondary zeolite concentration rotor 14. The frequency of use of the secondary desorption fan 17 is controlled: when it is detected that the VOCs concentration of the rotor outlet air exceeds the limit and reaches the standard for starting the desorption device, the secondary desorption fan 17 is started to allow VOCs to separate from the desorption area and enter the RTO module 18 for centralized combustion treatment. When it is detected that the VOCs concentration of the secondary zeolite concentration rotor 14 outlet air is low, the secondary desorption fan 17 stops running to save electricity, and the RTO module 18 stops running to save natural gas.

[0082] Example 2

[0083] This embodiment is an environmentally friendly and energy-saving air treatment system for a ship painting workshop with a single-stage zeolite rotor adsorption and return air. It is suitable for systems where the VOC treatment efficiency of the single-stage rotor is sufficient, there is almost no VOC leakage from the rotor, and the return air meets the requirements, such as Figure 2 As shown, it consists of an air treatment module, a paint shop, a zeolite wheel adsorption module and an RTO module.

[0084] The air handling module includes a fresh air damper 1', an air mixing chamber 2', an air handling unit 3', a supply air blower 4', an exhaust damper 10', and a return air damper 11'. The air mixing chamber 2', air handling unit 3', and supply air blower 4' are arranged sequentially along the air flow direction. Supply air blower 4' is connected to the air supply duct, driving the air through the heat and moisture treatment process and then into the paint shop 5.

[0085] The air supply fan 4' drives the air into the painting workshop 5', the main fan 7' of the zeolite rotor adsorption module drives the workshop exhaust air into the air filter 6' containing multi-stage filter elements with different efficiencies for filtration, and then enters the zeolite concentration rotor 8'. The adsorption fan 9 is connected to the adsorption zone of the zeolite rotor 10', and drives the clean air in the adsorption zone into the return air channel. The desorption fan 12' is connected to the desorption zone of the zeolite rotor 8', and drives the VOC concentrated air in the desorption zone into the RTO module 13' for VOCs treatment.

[0086] In the system, the fresh air damper 1', the exhaust air damper 10', and the return air damper 11' can all be opened and closed independently, and the air supply fan 4', the main fan 7', the adsorption fan 9', and the desorption fan 12' can all be opened and closed independently, and the speed can be adjusted in stages.

[0087] The environmentally friendly and energy-saving air treatment system for ship painting workshops with return air and single-stage zeolite rotor adsorption has two operating modes: high-concentration VOCs and low-concentration VOCs:

[0088] High-concentration VOCs mode: The air supply fan 4' is turned on, and the air is processed by the air treatment module to the required temperature and humidity state, and enters the ship painting workshop 5' through the air supply channel. The main fan 7' is turned on to drive the workshop exhaust air to pass through the air filter 6' for filtration, and then enter the zeolite concentration rotor 8'. Due to the high VOCs concentration, the adsorption fan 9' and the desorption fan 12' are turned on at the same time. The adsorption fan 9' drives the clean air in the adsorption area into the return air channel. Through the adjustment of the fresh air damper 1', the return air damper 11' and the exhaust damper 10', the fresh air ratio is adjusted and sent to the air mixing chamber 2', and then enters the air supply channel to complete the cycle; the desorption fan 12' drives the concentrated VOC air in the desorption area into the RTO module 13' for VOCs treatment.

[0089] Low-concentration VOCs mode: The air supply fan 4' is turned on, and the air is processed by the air treatment module to the required temperature and humidity state, and enters the ship painting workshop 5' through the air supply channel. The main fan 7' is turned on, driving the workshop exhaust to pass through the air filter 6' for filtration, and then enters the zeolite concentration rotor 8'. Since the VOCs concentration is low, in order to save energy, the desorption fan 12' can be turned off to allow VOCs to gradually accumulate on the zeolite concentration rotor 8'. The frequency of use of the desorption fan 12' is controlled: when it is detected that the VOCs concentration of the rotor outlet exceeds the limit and reaches the standard for starting the desorption device, the desorption fan 12' is started to separate the VOC from the desorption area and enter the RTO module 13' for centralized combustion treatment. When it is detected that the VOCs concentration of the zeolite concentration rotor 8' is low, the desorption fan 12' stops running to save electricity, and the RTO module 12' stops the furnace to save natural gas. The clean air adsorbed by the zeolite concentrator wheel 8 enters the return air duct driven by the adsorption fan 9', and is adjusted by the fresh air damper 1', the return air damper 11' and the exhaust air damper 10' to complete the fresh air ratio adjustment, and is sent to the air mixing chamber 2' and then into the supply air duct to complete the cycle.

[0090] The above-described embodiments do not fully demonstrate the complete cycle of air heat and humidity treatment within the air handling unit and all components of the air duct. The air handling unit may optionally utilize equipment such as a modular air conditioning unit and a modular rotary dehumidifier to regulate air temperature and humidity. During implementation, modifications to the air handling unit's circulation methods and equipment, such as the refrigeration heat pump, the use of different heat and humidity treatment methods, the installation of air handling accessories such as filters, mufflers, humidifiers, and sterilization devices within the fresh air duct, the selection of different air supply nozzles and air inlet grilles, changes in the fan position, or the addition or subtraction of the refrigeration heat pump cycle, the addition of fans and dampers, etc., without departing from the technical solution of the present invention, shall not be considered substantial improvements to the present invention and shall fall within the scope of protection of the present invention.

[0091] The above description of the embodiments is intended to facilitate understanding and use of the invention by those skilled in the art. It will be apparent that those skilled in the art can readily make various modifications to these embodiments and apply the general principles described herein to other embodiments without requiring inventive effort. Therefore, the present invention is not limited to the above-described embodiments. Improvements and modifications made by those skilled in the art based on the disclosure of the present invention, without departing from the scope of the present invention, should be within the scope of protection of the present invention.

Claims

1. An air treatment system for a ship painting workshop with return air, characterized in that: Including air treatment module, zeolite wheel adsorption module, RTO module; The input end of the air treatment module is connected to the output end of the zeolite wheel adsorption module, and the output end of the air treatment module is connected to the air inlet of the ship painting workshop; The exhaust port of the ship painting workshop is connected to the input end of the zeolite wheel adsorption module; The zeolite rotor adsorption module is a double-stage zeolite rotor adsorption structure; The zeolite rotor adsorption module includes a first-stage zeolite concentration rotor and a second-stage zeolite concentration rotor connected in series; The air processing module includes an air handling unit, an air mixing chamber provided at the input end of the air handling unit, a fresh air damper and a secondary return air damper respectively connected to the air mixing chamber, and an air supply fan provided at the output end of the air handling unit; Both ends of the first-stage zeolite concentration wheel are connected in parallel with bypass air passages; The inlet of the bypass air passage and the inlet of the adsorption zone of the first-stage zeolite concentration rotor are respectively provided with a bypass air damper and an adsorption air damper. The inlet of the bypass air passage and the inlet of the adsorption zone of the first-stage zeolite concentration rotor are connected, and a main fan is provided at the connection; The outlet of the bypass air passage is connected to the outlet of the adsorption zone of the first-stage zeolite concentration wheel, and a first-stage adsorption fan is provided at the connection; When the VOCs output from the ship painting workshop are at high concentrations, the first-stage zeolite concentration rotor and the second-stage zeolite concentration rotor simultaneously perform continuous adsorption and desorption work; When the concentration of VOCs is at medium or low levels, the first-level zeolite concentration rotor and the second-level zeolite concentration rotor enter intermittent working state as appropriate, wherein: the adsorption zones of the two zeolite rotors maintain continuous operation, and when the cumulative concentration of VOCs in the desorption zones of the two zeolite rotors exceeds the preset threshold and lasts for the preset time, the first-level zeolite concentration rotor and the second-level zeolite concentration rotor perform desorption work, desorbing the concentrated VOCs air into the RTO module for centralized combustion treatment.

2. The air treatment system for a ship painting workshop with return air according to claim 1, characterized in that: An air filter is connected to the inlet side of the main fan, and the input end of the air filter is connected to the air outlet of the ship painting workshop; A first-stage desorption fan is connected to the outlet of the desorption zone of the first-stage zeolite concentration wheel, and the output end of the first-stage desorption fan is connected to the RTO module.

3. The air treatment system for a ship painting workshop with return air according to claim 2, characterized in that: A first-stage return air damper is connected to the input port of the adsorption zone of the secondary zeolite concentration rotor, and a first-stage exhaust air damper is provided on the pipeline between the first-stage return air damper and the first-stage adsorption fan; A secondary adsorption fan is connected to the output port of the adsorption zone of the secondary zeolite concentration wheel, and the secondary adsorption fan is connected to the secondary return air damper; A secondary desorption fan is connected to the output port of the adsorption zone of the secondary zeolite concentration wheel, and the secondary desorption fan is connected to the RTO module.

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