Horizontal Packed Scrubbers

Written by Ralph Strigle, Jr. Consultant for Powell Fab & Mfg., LLC
Presented at the 73rd Chlorine Institute, LLC Annual Meeting

Chlorine is one of the most useful and economically important of the basic chemicals. Its largest single use is for the manufacture of plastics, mostly polyvinyl chloride (PVC). It is also used for manufacture of pharmaceuticals, aerosol propellants, agricultural chemicals, synthetic rubbers, dye stuffs, and paper pulp. No other material offers the economy of operation, simplicity of control, and safety of operation as chlorine for the treatment of potable water and sewage plant effluent. Other chemicals such as ozone, hydrogen peroxide, and potassium permanganate have been considered but are not widely used or accepted.

Since chlorine is classified as a toxic chemical, special requirements must be followed regarding its shipment and use. It has a distinctive, pungent, and irritating odor which is detectable at a level of even one ppm. This characteristic permits a user to recognize that a leak has occurred and to take corrective action. The Responsible Care (R) program directed by the Chemical Manufacturer's Association provides assistance and guidance to producers and distributors emphasizing the industry's commitment to the safe use of chlorine.

The Chlorine Institute is committed to the Responsible Care Program and provides additional support to the industry by aiding in the development of meaningful and useful regulations. Building and Fire Code groups can receive technical support from the Chlorine Institute in the form of data on the use and handling of chlorine. Publications such as the Chlorine Release and Scrubber pamphlets provide the necessary information regarding the safety and handling of emergency situations. Facilities that offer the potential of releases from areas of production, use, or packaging can obtain the necessary background and supporting data to permit meeting the EPA and OSHA guidelines and the SARA Title 3 requirements.

As most operations involving chlorine now are open to public scrutiny, implementation of adequate precaution to control emergency situations is essential. With all of the information which has been disseminated by the media, the average person is fearful of most chemicals. Even unintentional violations of federal regulations or local ordinances patterned after the Uniform Fire Code can incur large fines or closure of an operation. Thus, installation of an emergency chlorine scrubber that can contain the release of the total contents of a vessel becomes an important step in maintaining good community relations.

This paper will review the characteristics of many of the scrubber types for gaseous contaminants that are in a wide commercial use. The absorption theory applied as the background for the design of a multiple-bed packed scrubber utilizing horizontal gas flow will be given. The arrangement for conducting full-scale tests on this scrubber design will be shown. The results of four tests on the discharge from one-ton containers of chlorine at rates exceeding the Uniform Fire Code will be presented. Finally, the basis for the design of the commercial scrubber will be discussed.

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