i need to design a activated carbon bed to adsorb HC emission coming off the Secondary WW treatment tank.These HCs are DCPD(Dicyclopentadiene) and Benzene .Other HCs are ethane,ethylene,butadiene but in very minor quantity.
To find the bed volume , which HC should be taken as design basis?
i have to use Freundlich equation and the constants are only available for Benzene. However DCPD is present in much larger quantity then benzene.
Full Version: Hydrocarbon Adsorption Bed
CMP:
The only way to design a credible and operable adsorption unit for such small and specific quantities of contaminants is to rely on specific and empirical information and basic data.
The way to achieve this design is to work directly with a pre-selected Activated Carbon manufacturer. Note that I wrote "manufacturer" and not "supplier". It is the manufacturer that know the sorptive capacities of his adsorbent - and how they are obtained. The manufacturer also is the best source for detailed, specific regeneration methods (if regeneration is possible).
Adsorption, as a Unit Operation, is still in its infancy in this 21st century. No serious supplier is going to rely on an analytical adsorption calculation based on theoretical or semi-theoretical equations to come up with an industrial design of an adsorption unit. Do not rely on any theoretical equations or discussion on the subject. They are just that - theory, for now.
Rely on a design that will yield the following:
1) Two beds; one in service and the other in regeneration (if that is possible);
2) Size your beds based on manufacturer's recommended design data, such as superficial velocity, sorptive capacity, estimated bed breakthrough, regeneration requirements, adsorbent life;
3) Increase the bed size, decrease the superficial velocity, increase the regeneration, and decrease the estimated life by using engineering judgment and common sense; this is a conservative design and aimed at giving you a workable and operable unit that will perform without failure.
4) If adsorbent regeneration is not possible (or cost effective), then you will require to estimate a reasonable adsorbent "batch" life and be prepared to switch beds before a breakthrough. Spent adsorbent is sacrificed to waste disposal.
5) Invest in on-stream, accurate trace compound analyzers to monitor the migration of contaminants through the beds and accumulate all the data you can to form a good historical profile of the bed operation and the resulting product specifications. If your downstream process is very critical and cannot tolerate an off-spec feed, then you must invest in an Adsorber product Holding Tank - a vessel designed to "buy" you time in order to prevent a contaminant breakthrough to the downstream process and give you the opportunity to sample, analyze, and switch beds if need be.
I hope the above experience is of some help to you.
The only way to design a credible and operable adsorption unit for such small and specific quantities of contaminants is to rely on specific and empirical information and basic data.
The way to achieve this design is to work directly with a pre-selected Activated Carbon manufacturer. Note that I wrote "manufacturer" and not "supplier". It is the manufacturer that know the sorptive capacities of his adsorbent - and how they are obtained. The manufacturer also is the best source for detailed, specific regeneration methods (if regeneration is possible).
Adsorption, as a Unit Operation, is still in its infancy in this 21st century. No serious supplier is going to rely on an analytical adsorption calculation based on theoretical or semi-theoretical equations to come up with an industrial design of an adsorption unit. Do not rely on any theoretical equations or discussion on the subject. They are just that - theory, for now.
Rely on a design that will yield the following:
1) Two beds; one in service and the other in regeneration (if that is possible);
2) Size your beds based on manufacturer's recommended design data, such as superficial velocity, sorptive capacity, estimated bed breakthrough, regeneration requirements, adsorbent life;
3) Increase the bed size, decrease the superficial velocity, increase the regeneration, and decrease the estimated life by using engineering judgment and common sense; this is a conservative design and aimed at giving you a workable and operable unit that will perform without failure.
4) If adsorbent regeneration is not possible (or cost effective), then you will require to estimate a reasonable adsorbent "batch" life and be prepared to switch beds before a breakthrough. Spent adsorbent is sacrificed to waste disposal.
5) Invest in on-stream, accurate trace compound analyzers to monitor the migration of contaminants through the beds and accumulate all the data you can to form a good historical profile of the bed operation and the resulting product specifications. If your downstream process is very critical and cannot tolerate an off-spec feed, then you must invest in an Adsorber product Holding Tank - a vessel designed to "buy" you time in order to prevent a contaminant breakthrough to the downstream process and give you the opportunity to sample, analyze, and switch beds if need be.
I hope the above experience is of some help to you.
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