Selection of methods for treating VOCs in exhaust gases
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This post was last edited by ssj200820109 on 2019-1-24 at 13:46. There is exhaust gas with a pressure of 1.0 MPa; the main VOC is cyclohexane, with a concentration of around 3500 mg/m3. It is hoped to reduce this level to the emission standard of 120 mg/m3, and to recover as much cyclohexane as possible. After reviewing some literature, it seems that the adsorption method is more suitable for exhaust gases with medium to high concentrations; it’s quite difficult to achieve such levels. Do any of you have any good suggestions?
There are many ways to handle it; the key is to be willing to spend money!
Methods such as condensation, adsorption, and combustion can be chosen
In terms of cost-effectiveness, which method would be more suitable to implement? Could you explain it in detail?
Without considering combustion methods, can other methods achieve low emissions? I see that in the literature, the outlet concentrations for both the adsorption method and the compression absorption method are >1000 mg/Nm3. Could the economic aspects also be evaluated?
I haven’t studied similar methods in great detail, but I should point out that the gas after treatment still contains VOCs, and it basically cannot be released casually. To completely eliminate VOCs from the exhaust gases, apart from combustion, recycling is another option; however, there are issues related to pressure and flow rate, etc. So rather than focusing on costs, it’s better to consider the desired level of improvement. Methods such as absorption, adsorption, condensation, combustion, and recycling all have their own advantages and disadvantages... A combination of absorption/adsorption/condensation plus combustion can also be used
This question is a bit too general; what exactly are the components of exhaust gases and VOCs?； With these, in choosing the process ； Generally, it is treated by condensation, adsorption concentration, catalytic combustion, incineration (with heat recovery), or biological methods ； Economic analysis still requires VOC analysis ；
Your operating conditions are not clear, and it’s not specified whether there are any valuable components in the VOCs, so it’s impossible to discuss this.
The main VOC is cyclohexane, at a pressure of around 1 MPa. Without considering the combustion method, which approach would be more suitable for recovering the cyclohexane as much as possible?
In a pharmaceutical project I’ve just started working on, the solvent cyclohexane is first recovered using a condenser; thereafter, it is combined with other organic waste gases and sent to a high-efficiency condenser (the condensate is treated as hazardous waste), followed by treatment via water spraying and activated carbon adsorption.
The amount of this gas should be relatively small, right? Is the refrigerant in the condenser liquid nitrogen?