Date on Master's Thesis/Doctoral Dissertation

5-2012

Document Type

Master's Thesis

Degree Name

M. Eng.

Department

Chemical Engineering

Committee Chair

Willing, Gerold A.

Author's Keywords

Surfactant; Rendering; Adsorption towers; Packed towers; Contact angle

Subject

Surface active agents; Rendering industry--Waste disposal; Air filters

Abstract

Meat is a major component of the diet of an American. However, humans do not consume one-third to one-half of each animal raised for their needs. The leftover materials are subjected to processing in the meat rendering industry. The rendering industry turns the waste material into value added ingredients. During the rendering process, air pollutants are released. These air pollutants are odor nuisances in residential areas around rendering plants. These pollutants can be controlled by the use of multistage packed towers. The packed columns used by the rendering industry are distinctive because of the addition of animal fat in the air stream. The fat can agglomerate on the packing and clog the towers. To prevent this, operates introduce a surfactant into the liquid stream for the system. The surfactant serves two roles: suspend the fat in the packed tower so that it does not stick to the packing and clog the system and coat the packing to enhance mass transfer by allowing for the creation of an even water film over the packing. HydroSolution is located in Louisville, KY and specializes in serving the rendering industries. The company makes a treatment that is added to the air scrubber, which removes air pollutants from the airstream. The air scrubber system consists of a venturi connected to two packed towers in series. The company is interested in increasing the efficiency of the packed towers and reducing the amount of fat accumulation in the system. In addition, they would like to switch to an ecofriendly surfactant. To achieve their goals, a “green” surfactant was found that has the ability to replace the current one and the concentration needed to coat adequately the packing been determined. A contact angle analyzer was used to determine extent of water coating by the calculation of the contact angle between the water droplet and the packing. A result of this test showed the soak time for the polyethylene (PE) packing was critical for a hydrophilic layer to form whereas multiple alternating layers cab apparently form on polypropylene (PP). Better performance can be obtained using PE since the ultimate contact angle is lower than the PP packing which leads to a greater degree of wetting. A sonic dismembrator was utilized to suspend animal fat of the correct size in a surfactant solution; and a particle size analyzer calculated the diameter of the particles in the solution. A force balance on the particle diameter entering the packed tower at 500-600 nm determined the size. Any particles larger than 600 nm would fall out of suspension while smaller ones would remain and be transferred through the system. Once the equipment settings able to produce the proper size particles were found, the surfactant concentration needed to suspend fat was estimated. These results showed that more surfactant is needed to sufficiently coat the packing than to suspend fat. To increase the efficiency of the packed towers and reduce the probability of clogging, it is recommended that HydroSolutions switch to 70 ppm Bio-Soft GSB-9. This concentration is able to coat packing as well as 60 ppm Triton X-100 and suspend 3% animal fat.

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