At this stage, the biggest drawbacks is its gravure VOCs in an exhaust gas containing volatile air volume, low concentration, control technology which does not rely on a single activated carbon adsorption, but rather combined catalytic combustion technology, water vapor and a purge desorption regeneration through the bad Comprehensive management techniques such as processing. In this paper, through the analysis of the process flow of printing waste gas treatment, the research on the operation effect shows that the above treatment technology can purify and treat the VOCs waste gas of gravure printing to a large extent, and improve the energy saving and environmental protection effect.

In the case of gravure printing, a large amount of organic exhaust gas is usually generated, which is mainly caused by the evaporation of the organic solvent exhaust gas and the exhaust gas which is volatilized around the printing unit when the ink is dried. Limited by the explosive limit concentration value, it will increase the exhaust gas emissions of the drying oven. In addition, it will volatilize a variety of pollutants with low concentration: such as ethyl acetate, acetone, benzene-free ink, and ethanol produced during operation.

1 system process

Adsorbents are the decisive factor in the use of adsorption process for waste gas treatment. The adsorbent used for purifying and treating large amounts of organic waste gas is honeycomb-like activated carbon. This adsorbed carbon is superior to ordinary activated carbon in adsorption performance and has the characteristics of small airflow resistance. At the same gas flow rate, the airflow resistance of the honeycomb activated carbon is about 10% less than that of the same type of particulate carbon.

The process of gravure printing activated carbon technology mainly uses the first pre-filter to filter, and after the surface is cooled, it is introduced into the adsorption device for adsorption. After the adsorption reaches saturation, the activated carbon is desorbed using steam. The specific operation process is shown in Figure 1.

1.1 system material cycle characteristics

The entire process of gravure printing VOCs exhaust gas purification treatment is controlled by an editable logic controller, which can realize functions such as recycling, alternating adsorption, and automatic switching. The characteristics of the system material cycle are mainly the following aspects:

(1) To achieve the collection of printing exhaust gas, it is necessary to adjust the high-pressure fan to a micro-negative pressure so that it can enter the filtering process. After the exhaust gas temperature adjusting device enables the exhaust gas to smoothly enter the desorption device, the exhaust gas can be treated into a clean gas by the adsorption tank, so that recycling can be realized.

(2) After the adsorption of the printed exhaust gas, the activated carbon can generate a mixed gas by using a steam desorbing device, and after a plurality of heat exchanges, a condensed liquid is formed, and then the condensed liquid is rectified, and the organic product can be purified for production.

(3) To oxidize the organic matter in the exhaust gas into harmless water and carbon dioxide, it is necessary to catalytically burn the gravure-printed exhaust gas by catalytic combustion technology, which can effectively ensure the safety and quality of the purification treatment of the equipment.

1.2 Pretreatment of washing and filtration process

Since gravure printing produces organic fumes of particulate paint mist during operation, it is necessary to thoroughly remove the particulate paint mist contained in the organic waste gas before entering the adsorption tank. Intermittent high pressure showering is used to treat molecular diffusion and the like. This allows the macromolecules contained in the exhaust gas to enter the adsorption tank for adsorption treatment.

1.3 Activated carbon adsorption purification process

Usually, the adsorption device is composed of three adsorption cans which are capable of circulating desorption adsorption, regeneration and gas drying of the exhaust gas. The so-called gas drying refers to the use of activated carbon fiber to cool the gas, which can effectively remove the residual steam in the gas, and achieve the optimal adsorption effect of the adsorption tank. The exhaust gas generated during the printing process is introduced into the adsorber by the centrifugal fan. This will enable the purified gas to reach the discharge standard.