Adsorption Desorption Catalytic Combustion Waste Gas Treatment Equipment

Waste Gas Treatment Equipment: Adsorption and desorption + catalytic combustion equipment

(1) Equipment introduction

Activated carbon adsorption and desorption refers to the use of activated carbon molecular sieves to adsorb pollutants in industrial waste gases, and select appropriate molecular sieves for different waste gas components. When the molecular sieve reaches saturation, the pollutants are desorbed, and catalytic combustion technology is used to deeply oxidize the organic matter in the industrial waste gas into carbon dioxide and water, thereby achieving the purpose of purification.

Adsorption and desorption purification equipment generally consists of exhaust gas collection unit, pretreatment unit, adsorption unit, catalytic combustion unit, desorption unit, heat exchange unit, etc.

(2) Working principle of molecular sieve adsorption and desorption

Under the action of the adsorption fan, the organic waste gas enters the pre-filter box from the air inlet. The pre-filter filters and intercepts the particulate matter in the waste gas to prevent the particulate matter from entering the adsorption layer and clogging the molecular sieve micropores, affecting the purification effect.

Then the exhaust gas enters the adsorption and desorption boxes on both sides through the pre-filter (a bypass insulation layer is provided in the middle, and the bypass valve is directly opened for discharge when the concentration of organic exhaust gas meets the standard), and the adsorption layer in the adsorption and desorption box adsorbs and purifies the organic exhaust gas.

The catalytic combustion device is arranged above the adsorption layer. When the zeolite molecular sieve (or activated carbon molecular sieve) adsorption layer is close to saturation (the exhaust concentration reaches the set value), the PLC controller automatically closes the air intake valve, opens the catalytic combustion air intake valve and the catalytic combustion electric heater.

The fresh air is heated to a certain temperature by the energy-saving device under the action of the desorption fan and then enters the adsorption layer for desorption. The desorbed gas enters the catalytic combustion and burns and oxidizes to CO2, H2O and other substances under the action of the catalyst. The burned gas is discharged from the exhaust port, and the product has no secondary pollution.

(3) Process analysis

①The process flow of adsorption concentration-desorption and desorption-catalytic decomposition. It consists of 2 activated carbon adsorbers and 1 catalytic decomposer (supplemented by low-pressure fans, valves, etc.). After the exhaust gas is pretreated to remove dust and granular substances, it is sent to activated carbon adsorbers A and B. When activated carbon adsorber A is close to saturation, the treated gas is first automatically switched to activated carbon adsorber B (activated carbon adsorber A stops adsorption operation) , and then use hot gas flow to desorb and desorb the activated carbon adsorber A to desorb organic matter from the activated carbon. During the desorption process, the organic waste gas has been concentrated, and the concentration has increased dozens of times compared to the original, reaching more than 2000 ppm. The concentrated waste gas is sent to the catalytic decomposition device, and is finally discharged as CO2 and H2O.

② After desorption and desorption are completed, activated carbon adsorber A enters the standby state. When activated carbon adsorber B is close to saturation, the system automatically switches back and desorbs and desorbs activated carbon adsorber B at the same time. This cycle works.

③When the concentration of organic waste gas reaches above 2000ppm, spontaneous combustion can be maintained in the catalytic bed without external heating. This solution not only greatly saves energy consumption, but also reduces equipment investment because the processing capacity of the catalytic decomposer only requires 1/5 of the original exhaust gas treatment capacity (60,000m3/h). This solution is suitable for both continuous and intermittent work.

④The desorption and desorption of a single activated carbon adsorber takes about 2-3 hours.

⑤ The adsorption fan is controlled by a frequency converter and can be adjusted according to the required air volume or the net negative pressure at the device inlet.