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Printing Exhaust Gas Treatment Project of Wuxi Dayou Co., Ltd.

作者：中环绿洲时间：2026-05-18 11:12:395次浏览

信息摘要：

Entrusting Party: Wuxi Dayang Co., Ltd.

Design Institution: Zhonghuan Lvzhou (Shandong) Equipment Manufacturing Co., Ltd.

1. Project Overview

Wuxi Dayang Co., Ltd. is a diversified manufacturing enterprise. Its core business scope includes the production and sales of precision cavity molds, toys and hardware accessories. It also involves electronic product research and development, packaging and decoration printed matter printing, production, sales and maintenance of industrial automatic control system devices. In addition, the company carries out wholesale and import and export business of batteries, power adapters and other products. With comprehensive business layout and solid technical strength, the company provides high-quality products and services for many industries and occupies an important position in the regional industrial structure.

In the printing process of packaging and decoration printed matter, links such as ink mixing, printing and drying generate a large amount of printing waste gas dominated by volatile organic compounds (VOCs). The main components include toluene, xylene, ethyl acetate, ethanol and a small amount of ink particles. Such waste gas has a strong pungent odor. Direct discharge without effective treatment will not only harm the respiratory system and nervous system health of operators in the printing workshop, but also pollute the surrounding atmospheric environment and increase the risk of ozone pollution and haze. Meanwhile, it violates national and local environmental protection regulations. To meet the environmental protection standards of the printing industry and realize compliant waste gas discharge, Wuxi Dayang Co., Ltd. entrusts Zhonghuan Lvzhou (Shandong) Equipment Manufacturing Co., Ltd. to customize a special printing waste gas treatment design scheme with two-stage activated carbon adsorption equipment as the core.

2. Pollutant Analysis and Hazards

2.1 Main Pollutants

Combined with the packaging and decoration printing process characteristics of Wuxi Dayang Co., Ltd., the core pollutants of this project are mixed waste gas of VOCs and ink particles, which are mainly generated in all links of the printing process. The specific components are highly correlated with ink types and printing materials, and divided into three categories: first, VOCs generated by solvent volatilization during ink mixing and printing, with toluene, xylene, ethyl acetate and isopropanol as the core components, accounting for more than 85% of the total waste gas; second, unattached tiny ink particles during printing, with particle sizes mostly ranging from 0.5 to 5 micrometers, mainly composed of resin, pigments and fillers; third, residual solvents volatilized by high temperature in the drying process, mainly low-boiling alcohols and esters, mixed with trace paper fiber dust.

2.2 Formation and Hazards of Pollutants

Such waste gas is mainly generated by natural volatilization of solvents in printing ink, atomization under printing pressure and thermal-driven volatilization in the drying process. Its hazards are irritating, cumulative and environmentally destructive, which are reflected in three dimensions: human health, production safety and ecological environment.

2.2.1 Hazards to Human Health

Benzene series such as toluene and xylene have strong neurotoxicity. Short-term inhalation will cause dizziness, nausea, blurred vision and other symptoms. Long-term exposure may lead to neurasthenia syndrome and damage the hematopoietic system and reproductive function. Esters such as ethyl acetate irritate conjunctiva and respiratory mucosa, causing sore throat, cough and other discomforts. Ink particles are easy to deposit in the lungs after inhalation, increasing the risk of occupational diseases such as pneumoconiosis.

2.2.2 Production Safety Risks

VOCs components such as toluene and ethyl acetate are flammable and explosive substances with an explosion limit of 1%-10%. After accumulating in the closed space of the printing workshop, they are extremely prone to explosion and fire accidents in contact with electric sparks generated by equipment operation or high temperature in the drying process. At the same time, ink particles adhering to the equipment surface will affect printing accuracy, increase product rework rate and production cost.

2.2.3 Ecological Environmental Impacts

As important precursors of ozone pollution and PM2.5, VOCs participate in photochemical reactions after being discharged into the atmosphere, aggravating regional haze and photochemical smog pollution. Ink particles settle with rainwater to pollute soil and water bodies. Some pigment components have heavy metal toxicity, which accumulates through the food chain and destroys the balance of the ecosystem. The strong pungent odor will also affect the living quality of surrounding residents, trigger environmental complaints and damage the social image of the enterprise.

3. Design Basis and Principles

3.1 Design Basis

Environmental Protection Law of the People's Republic of China (Revised in 2015)
Atmospheric Pollution Prevention and Control Law of the People's Republic of China (Revised in 2018)
GB 16297-1996 Comprehensive Emission Standard of Air Pollutants
GBZ 2.1-2019 Occupational Exposure Limits for Hazardous Factors in Workplace Part 1: Chemical Hazardous Factors
GB 3095-2012 Ambient Air Quality Standards
HJ/T 387-2007 Industrial Waste Gas Adsorption and Purification Device
HJ 2026-2013 Technical Specification for Industrial Organic Waste Gas Treatment Engineering by Adsorption Method
GB 30799-2014 Emission Standard of Pollutants for Electronic Industry (Involving electronic accessories printing links)
GB 28661-2012 Emission Standard of Air Pollutants for Printing Industry
GB 50243-2016 Code for Acceptance of Construction Quality of Ventilation and Air Conditioning Engineering
GB 50235-2010 Code for Construction and Acceptance of Industrial Pipeline Engineering
National electrical industry standards: GB 50054-2011 Code for Design of Low Voltage Power Distribution
GB 50034-2013 Standard for Lighting Design of Buildings
Mature cases and technical data of waste gas treatment of printing enterprises at home and abroad

3.2 Design Principles

Accurate Compliance Principle: The discharged printing waste gas shall strictly comply with GB 28661-2012 and GB 16297-1996 standards, in which VOCs emission concentration ≤20mg/m³, toluene + xylene emission concentration ≤5mg/m³, particulate matter emission concentration ≤10mg/m³, meeting local environmental protection requirements and relevant double carbon policies.
Graded Purification Principle: Adopt the combined mode of pretreatment impurity removal and two-stage adsorption. Filter cotton is used to remove ink particles firstly, then the first-stage activated carbon adsorbs high-concentration VOCs, and the second-stage activated carbon deeply purifies residual components to ensure thorough purification.
Safety Adaptation Principle: The equipment adopts explosion-proof design, equipped with VOCs concentration online monitoring, automatic alarm and nitrogen purging system. The system air volume accurately matches the number of printing machines and can be dynamically adjusted with production load to adapt to multi-variety printing operation demands.
Economic and High-efficiency Principle: High iodine value columnar activated carbon is selected to improve adsorption capacity and extend replacement cycle. The two-stage adsorption tower adopts one-use and one-standby design to ensure no production interruption during maintenance, controlling operation and maintenance costs while ensuring treatment effect.

4. Design Objectives

Through the construction of the two-stage activated carbon adsorption waste gas treatment system, the following core objectives are achieved to build a green printing demonstration enterprise:

The purification efficiency of printing waste gas is ≥98%. After treatment, VOCs ≤20mg/m³, toluene + xylene ≤5mg/m³, particulate matter ≤10mg/m³ and pH value ranges from 6 to 9, which strictly comply with national and local environmental protection standards to ensure stable compliant exhaust emission.
A special exhaust funnel with a height of no less than 15 meters is constructed. Sampling platforms, monitoring holes and online monitoring equipment installation interfaces are arranged in accordance with specifications to ensure sufficient high-altitude diffusion of purified waste gas and avoid impacts on the surrounding environment.
The pollutant concentration at each operating point in the printing workshop is controlled within the limit of GBZ 2.1-2019 standard, among which toluene ≤50mg/m³ and xylene ≤50mg/m³. The pungent odor is completely eliminated to improve the workshop operating environment and reduce occupational disease risks.
The system realizes automatic operation and intelligent monitoring with functions such as VOCs concentration over-limit alarm, activated carbon saturation early warning and equipment fault self-diagnosis. The annual stable operation time is ≥8200 hours to meet the enterprise's multi-shift continuous production demands.

5. Printing Waste Gas Treatment Process Design and Description

5.1 Process Selection Basis

The printing waste gas of Wuxi Dayang Co., Ltd. has prominent characteristics including complex VOCs components, medium concentration, ink particles, scattered discharge points but concentrated in the printing workshop. The enterprise's business covers multi-category printing, requiring high purification efficiency, safety and operation flexibility of the waste gas treatment system. Therefore, the combined process of pretreatment + two-stage activated carbon adsorption is selected for this scheme. This process is maturely applied in the packaging and printing industry with the following core advantages:

Clear purification levels and thorough effect: In the pretreatment stage, primary and medium-efficiency filter cotton removes more than 95% of ink particles to avoid blocking activated carbon pores. The first-stage activated carbon adsorption tower treats more than 80% of high-concentration VOCs, and the second-stage adsorption tower deeply purifies residual components with a total purification efficiency of more than 98%.
Excellent safety performance: The main body of the equipment is made of Q235 carbon steel with anti-corrosion treatment, equipped with explosion-proof fans and static elimination devices inside. Fresh air dilution is automatically started when the VOCs concentration exceeds the standard, combined with the nitrogen purging system to completely eliminate explosion risks.
Strong adaptability: The system can adjust air volume according to the number of running printing machines to adapt to intermittent or continuous production modes. The two-stage adsorption tower is convenient for switching, and production will not stop during activated carbon replacement to ensure production continuity.
Balance of economy and environmental protection: High iodine value activated carbon has large adsorption capacity with a replacement cycle of 3-6 months and controllable operation and maintenance costs. Waste activated carbon is recycled or incinerated by qualified institutions in line with hazardous waste management specifications.

5.2 Process Flow Chart

Waste gas from printing machine/drying box → Universal gas collecting hood/Closed hood → Anti-corrosion ventilation pipeline → Primary filter cotton (large particle removal) → Medium-efficiency filter cotton (tiny ink particle removal) → Primary activated carbon adsorption tower → Secondary activated carbon adsorption tower → Explosion-proof induced draft fan → Special exhaust funnel → Compliant discharge

Supporting System: Activated carbon saturation monitoring device → Automatic switching valve → Nitrogen purging system → VOCs online monitor → Central control early warning platform

5.3 Detailed Process Description

Efficient source collection: Differentiated gas collection devices are set according to the characteristics of different printing equipment. Offset printing machines are equipped with side suction universal gas collecting hoods with wind speed controlled at 1.2-1.5m/s. Drying boxes adopt fully closed gas collecting hoods to ensure no leakage of high-temperature waste gas. All gas collecting hoods are summarized through FRPP anti-corrosion pipelines, and the internal pipeline wind speed is maintained at 12-15m/s to avoid ink particle deposition and blockage.
Pretreatment impurity removal: The waste gas firstly passes through primary filter cotton (filtration accuracy: 10μm) to remove paper fibers and large-diameter ink particles, and then passes through medium-efficiency filter cotton (filtration accuracy: 1μm) to capture tiny particles with an impurity removal efficiency ≥95%. It effectively protects the subsequent activated carbon adsorption layer and extends its service life. The filter cotton adopts a drawer-type design for regular replacement.
Two-stage adsorption and purification: The pretreated waste gas enters the two-stage activated carbon adsorption system. The first-stage adsorption tower is filled with columnar activated carbon with iodine value ≥1000mg/g, which removes more than 80% of high-concentration VOCs through physical adsorption. Residual unadsorbed VOCs enter the secondary adsorption tower and are deeply intercepted by high specific surface area activated carbon to ensure qualified VOCs concentration after purification. The adsorption tower adopts parallel double-tower design with one tower for operation and the other for standby. It automatically switches when the resistance of the operating tower reaches 1500Pa.
Safety guarantee and monitoring: The system is equipped with a VOCs online monitor to real-timely monitor the concentration at the inlet and outlet of the adsorption tower. When the inlet concentration exceeds the standard (≥500mg/m³), the fresh air dilution device is automatically started. An early warning signal is sent before activated carbon saturation to remind timely replacement. The equipment is built with a nitrogen purging system to replace VOCs before adsorption tower maintenance and eliminate hot work risks.
Tail gas emission and operation maintenance: The purified gas is lifted to a 15-meter-high exhaust funnel for discharge by an explosion-proof induced draft fan. The online monitoring data installed on the exhaust funnel are synchronously uploaded to the enterprise central control room and local environmental protection platform. The replaced waste activated carbon is collected in a sealed manner and recycled or safely disposed of by institutions with hazardous waste disposal qualifications to realize closed-loop environmental management.

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