TECHNOLOGY
Odor Control System Operates Successfully Designed by Catalytic Combustion for Jersey State polymerization plant, system overcomes acrylate odor problem A versatile and effective system for disposing of an acrylate odor problem in a polymerization plant has now completed a year's satisfactory operation. The system, installed at Jersey State Chemical's Haledon, N.J., plant, consists of a network of flexible tubing and ducts coupled to a roof-mounted catalytic combustion unit. The system destroys odors from six separate sources, some of which are as much as 60 ft. away from the oxidation unit. Jersey State Chemical developed the collection method; Catalytic Combustion Co., a division of Universal Oil Products, designed the vapor oxidation system. Jersey State Chemical makes polymer and copolymer emulsions for use in water-based paints, floor polishes, flexible adhesives, and for use as pigment binders, sizing, fillers, and the like. Raw materials include methyl, ethyl, butyl, and 2-ethylhexyl acrylates and the corresponding rriethacrylates, plus a number of other monomers. Certain monomers, particularly the acrylates, give off vapors which are both flammable and highly odorous. These vapors must be either treated or eliminated. Despite care in design and construction of process equipment, ducts, and piping to handle these troublesome monomers, vapor leakage or spills will occur. Even in concentrations of a few parts per million, acrylates will give off an unpleasant odor. So Jersey State decided to carry out a detailed study of odor correction methods. The company looked at various odor control approaches from two angles: their effectiveness and their cost. Of the eight approaches investigated, two were recommended for effectiveness close to 100%. These were catalytic combustion and incineration. The catalytic method got the nod. Cost of this approach is considerably less than 46
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incineration for the initial investment— and the operating expense is about half as much. As a result, Jersey State contacted Catalytic Combustion and finally chose to install its vapor oxidation system. Jersey State also worked out an unusually versatile collection system engineered to the plant's particular needs. The system has now been operating at the Haledon plant for about a year and results have been excellent, according to E. D. Szubin, director of research at Jersey State. Six Sources. Jersey State's collector system deals with six major sources of vapors in the plant. These are the unloading point, the reactor room, the two reactors, the head tank, and the lab. At the unloading site, two lengths of flexible, expansible 12-in. diameter tubing are attached to the collection ducts which lead to a main manifold. These tubes are simply placed over any leak and the vapors are removed. Flexible tubing is also used in the reactor room to collect vapors from the auxiliary vessels, pumps, meter, or the head tank. A major source of odor, the reactors steadily release vapor throughout the polymerization cycle, sometimes release a very heavy concentration of vapor during vacuum stripping. Stationary ducting leading from the reactors to the manifold is used here. This approach also handles vapors in the plant's laboratory. Release of odors from these various sources is intermittent. Therefore, each collector manifold or duct, except that from the lab, is equipped with blast gates or shutoff valves. This keeps the system from collecting air when no vapors are present. Platinum Group. Catalytic combustion is the low temperature, flameless oxidation of combustible gases and vapors in the presence of a catalyst.
The catalyst used is a member of the platinum group and is coated on a ribbon-shaped nickel alloy support material. Placed in the gas stream, it oxidizes even trace amounts of acrylates and other vapors at temperatures considerably below those used in incineration methods. A single unit using this system is mounted on the roof of the plant. In operation, vapors are pulled by an exhaust fan from the main collection manifold into the insulated and jacketed unit. Here a gas-fired preheat burner raises the temperature of the vapors to catalytic Operating temperature and holds them there. Then the vapors pass through the catalyst element and are oxidized. The resulting gases are exhausted. Controlled from the reactor room of the plant, the system operates automatically. Concentration of vapors handled by it will vary through the day. Therefore, the controls are designed to take advantage of heat released on the catalysts during peak vapor release cycles. Catalytic operating temperature is principally maintained by the preheater. However, the latent heat of combustion of the vapors is released as the vapors are oxidized, and this also serves to heat the gas stream. As the concentration of the vapors increases, the system automatically reduces the heat supplied by the preheater, taking advantage of the latent heat. Result is a saving in fuel.
Dravo Obtains License for Metal Degassing Process A production line method for degassing molten steel is being introduced in the U.S. by Dravo Corp., Pittsburgh, Pa. The company has been licensed by two West German firms, Reinstahl Huttenwerke, A.G., and W. C. Heraeus, G.m.b.H., to design, manufacture, and sell Ruhrstahl-Heraeus (R-H) circulating-flow vacuum degassing equipment in the U.S. and Canada. The R-H process, according to Dravo, features high-efficiency gas removal, thorough mixing of the metal bath, mechanical simplicity, and flexibility of operation. Each factor contributes to the system's low operating and capital costs. It can be installed with little or no plant modification, Dravo adds. Continued on page 48
