The purification efficiency of liquid absorption method is 60%~ 80%, which is suitable for treating low concentration and large volume of organic waste gas, but there are secondary pollution.
The purification rate of catalytic combustion method is 95%, which is suitable for the treatment of high concentration and small air volume organic waste gas. The disadvantage is that it has strict requirements on the treatment object and requires high gas temperature. In order to improve the exhaust gas temperature, it needs to consume a lot of fuel, so the operation cost is very high.
The purification efficiency of activated carbon adsorption method is 99.2%~99.3%. For the treatment of large air volume and low concentration of organic waste gas, it is agreed that this method is the most mature and reliable technology at home and abroad, but the T art process is too long, the operation cost is high, and it is often more difficult to need a stable steam source.
In view of these problems, combined with the characteristics of this graduation design and only body requirements, the use of activated carbon fixed bed adsorption system for industrial organic waste gas purification, the selection of honeycomb activated carbon as adsorbent.The process system is compact and integrated with adsorption and desorption.activated carbon suppliers canada
The waste gas produced in the production process, mainly of benzene, toluene, xylene, etc., according to the nature of benzene class, this scheme adopts the active carbon as adsorbent to absorb the waste gas, the adsorption bed configuration 2 sets of above commonly, use rotation, when one adsorption bed adsorption of organic adsorption amount of reach regulation, change to another Ⅰ adsorption bed for adsorption purification operation, at the same time to take off one in front of the adsorption bed with regeneration.Desorption is carried out by heating under the action of additional steam, and most of the hotgas released by the tail gas is used for desorption and regeneration of adsorbent in the adsorption bed to achieve the utilization of waste heat.The waste gas volatilized from production is sent to the adsorption tower by centrifugal fan with activated carbon as adsorbent. The gas in the tower is processed through the activated carbon filter layer from right to left and from bottom to top, and the purified gas is discharged into the atmosphere through the exhaust pipe.The purification rate of catalytic combustion method can reach 95%, but it is suitable for the treatment of high concentration, small air volume and high exhaust gas temperature of organic waste gas, and the gas temperature is higher, in order to improve the exhaust gas temperature, it needs to consume a lot of energy.The most used method is a catalytic combustion method, adsorption, it mainly particles or honeycomb carbon as adsorbent, to ensure the continuity of production, generally set up two adsorption bed used interchangeably, as a result of the switching cycle at least for ld, so adsorption bed volume big, adsorbent dosage, heavy equipment, large investment, operation trouble;As the bed volume is large, it is easy to appear the combustion and explosion caused by the accumulation of adsorption heat.To solve these problems, the adsorber of the existing new device adopts a multi-unit shunt combination structure, and uses a new material -- activated carbon fiber as adsorbentThe kinetic activity value of adsorbent is the main basis for the design of adsorption system.
The adsorption rateThe adsorption process often takes a long time to reach equilibrium, and the contact time is limited in the actual production process.Therefore, the amount of adsorption depends on the adsorption rate, and the adsorption rate is related to the adsorption process, the adsorption process can be divided intoThe adsorption process often takes a long time to reach equilibrium, and the contact time is limited in the actual production process.Therefore, the amount of adsorption depends on the adsorption rate, and the adsorption rate is related to the adsorption process, which can be divided into the following steps:activated carbon for water filter
(1) External diffusion, the adsorbate from the main air flow through the air film around the particles to the outer surface of the adsorbent; (2) Internal diffusion, the adsorbate from the outer surface through micropores to the surface of the adsorbent micropores
(3) adsorption, the adsorbent reached the microporous surface of the adsorbent is adsorbed
(4) The desorbed adsorbate diffuses to the main body of the gas phase through internal and external diffusionPhysical adsorption process is generally controlled by internal and external diffusion, chemical adsorption is controlled by both surface dynamics and internal and external diffusion.Because of the complexity of the adsorption process and many influencing factors, it is difficult to derive the rate theoretically, so it is generally determined by experience or model experiment.