Technology
New process equipment unveiled at Chem Show The Exposition of Chemical Industries—popularly called the Chem Show—is a showcase for the state of the art in chemical process equipment and process control instrumentation. Because of the slowly evolving nature of most areas of process equipment, it seldom sports radical new design departures. Nevertheless, there is usually a smattering of new developments. And occasionally the show provides hints of changing industry attitudes. This year's edition—the 29th, held early this month in New York City's Coliseum—had both, as highlighted in the following reports by Stephen C. Stinson and James H. Krieger. The Chem Show, which had been a biennial event but which in recent years alternated annually between New York and Chicago, will be missing from the calendar next year. The next show is scheduled for December 1983 and subsequent odd years in New York, with a regional show scheduled for 1984 in Chicago.
Recovery of materials and energy stressed Many exhibitors this year showed a wide range of equipment for waste incineration and materials recovery. Only a few years ago, such firms would have aimed their products at waste disposal and pollution abatement. Now the emphasis is on energy management and materials recovery, with environmental benefits described as a bonus. One example of this trend is removal of volatile organics from gas streams by incineration or solvent recovery before venting to the atmosphere. Regenerative Environmental Equipment Co. (REECO), Morris Plains, N.J., was among manufacturers showing incineration equipment. Edwards Engineering Corp., Pompton Plains, N.J., introduced a flexible, small-scale version of its solvent recovery system. Choosing between incineration and recovery hinges on economics of the two approaches. Low organic vapor concentrations or streams with mixtures of solvents incline the choice toward incineration. This is because dilute streams require energy-intensive chilling of large volumes to condense small amounts of liquids. Mixed streams require distillation at
the end to recover pure solvents. More concentrated monocomponent vapors of high-priced aromatics, ketones, alcohols, aldehydes, monomers, or ethers may favor recovery. REECO president James H. Mueller described the most recent experience with the company's thermal oxidation system at Wolverine Aluminum Corp.'s Lincoln Park, Mich., plant. Wolverine sends spent drying air from a coil coating line to the unit and uses incineration heat to
help fire waste heat boilers and to heat the drying section. Gregory C. Smith, president and chairman of Wolverine, says the $2.5 million unit is cutting natural gas use 50%. The REECO technology uses five towers packed with saddle-shaped ceramic pieces to heat waste gas almost to combustion temperatures and to absorb incineration heat, thus cooling the packing. Heated waste gas passes to a central chamber where a gas-fired torch functions as a pilot
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REECO was among manufacturers showing incineration equipment Dec. 21, 1981 C&EN 27
Technology saves Kay-Fries $560,000 per year in by salts, was featured by Midlanddisposal costs and gains the company Ross Corp.'s Surface Division, Tole$700,000 annually in fuel values. do. The Midland-Ross system hanCombustion gases from the Stony dles semiliquid sludges or bottoms Point installation go to a quencher for and converts these to ash or char for cooling before passing through a disposal. The pyrolytic incineration caustic scrubbing in a glass fiber-re- option of the firm also makes incininforced polyester tower and venting eration heat available for waste-heat to the atmosphere. During mainte- boilers or other process needs. nance of the waste-heat boiler, operA typical Midland-Ross installaators can bypass the boiler and send tion takes 1000 to 6500 lb per hour of combustion gases directly to the organic sludges onto a turntable quencher and scrubber. hearth which undergoes two revoluHirt engineers emphasize the need tions per hour. Heating at 1000 to for systems designed to the user's own 1600 °F in a reducing atmosphere waste stream rather than adaptation produces 60 to 97% weight reductions of one design to all uses. For example, during one revolution, leaving resia waste stream containing sodium or dues for recovery or disposal that are calcium salts would erode certain re- usually harmless. Gasified organic fractory materials in combustion materials go to a reactor, where gases chambers. Hirt uses specially de- burn at 2500 to 3000 °F. Combustion Edwards focused on solvent recovery signed burners that crack and atom- only of pyrolytic gases eliminates ize organic wastes completely in needs for baghouses, scrubbers, and light to complete combustion there. ignition tubes before completion of precipitators for salts. Midland-Ross engineers point out Combustion gases enter a different oxidation in the main combustion tower with cooler packing and heat chamber. The company also arranges that more auxiliary fuel may be the packing there. Cycling among the combustion in stages for nitrogen- needed to vaporize water in sludges towers heats waste gas for combustion containing streams to avoid forma- that have excessive amounts of water. On the other hand, the great reducand cools combustion gases before the tion of nitrogen oxides. Technology suitable for solid waste, tions in waste volumes that are posgases are used elsewhere, while the tower packing is alternately heated which also avoids problems presented sible lower transportation costs. D and cooled. On the recovery side, Edwards has adapted its system for condensing New agitators, process instruments introduced gasoline vapors at distribution terminals for use in the printing, coating, New developments dotted the exhi- the impeller in a rigid, corrosion-redrug, and chemical industries. Gas bition floors at the Chem Show, both sistant glass-to-glass joint. At the show, Pfaudler exhibited a streams enter a precooler unit, which in plant equipment and in process removes moisture. Gases then go to instruments. Among the equipment 54-inch span anchor agitator shaped the condensing column, which oper- offerings were new designs of agita- to conform to the contour of a 1000ates as low as —125 °F. A series of tors and a tablet press. Among the gal glassed-steel reactor. Chemineer-Kenics, Dayton, Ohio, vanes at the top of the column traps new instruments were an oxygen anintroduced a new line of gear-driven, residual moisture as frost. A second alyzer and a level transmitter. section with more closely spaced One of the new agitators is a two- side-entering agitators designed to vanes condenses solvent. piece, anchor-style, glassed-steel unit broaden the use of such agitators. The Solvent recovery capacities in Ed- from Pfaudler Co., Rochester. The right-angle gear drive with high-effiwards' systems range from about 5 to unit is the second to use the compa- ciency, spiral-bevel gearing makes it 500 gal per hour. Operators can in- ny's Cryo-Lock design for a shrink- possible to keep the drive portion of crease refrigeration compression fitted joint, following the introduction the unit close to the side of a tank. Historically, the company says, suction pressures during periods of of the concept two years ago for a side-entering agitators have found high solvent loadings to increase ca- four-blade turbine agitator. With the Cryo-Lock approach, the use on oil storage tanks. But, the pacity temporarily without losing efficiency at constant condensation impeller is separated from the shaft company believes, such units, with for installation in a reactor, allowing shorter shafts, could find broader use temperature. Whereas REECO and Edwards it to be lowered into the vessel in chemical applications because of aim their systems at treatment of or- through an existing top head opening. the ease of mounting and servicing, ganic vapors, the incineration system The anchor-style agitator thus can be both of which are carried out at of Hirt Combustion Engineers, used in closed-top glassed-steel re- ground level. Also historically, the company Montebello, Calif., handles combus- actors. Also, replacement of a contible gases as well as liquid organic ventional one-piece glassed anchor notes, side-entering agitators have chemical wastes. An example of such agitator requires the removal of the used a single inside mechanical seal. an application is the unit installed by entire top head of a clamp-top vessel, To make the unit attractive for broader applications, the company Hirt at Kay-Fries, Stony Point, N.J., a time-consuming operation. Assembly of the two-piece agitator has designed a double mechanical which burns 500 lb per hour of chlorinated solvents plus a waste gas of is done inside the reactor. Liquid ni- seal. The seal incorporates a cavity 50% hydrogen cyanide in nitrogen. trogen circulated in the shaft cools pressurized with hydraulic fluid so Incineration heat helps fire a waste the shaft, shrinking it. The shaft then any leakage is into the vessel. The new pharmaceutical tableting heat boiler that delivers 250-psig is lowered into the impeller hub and, steam. Hirt estimates the system after warming up, is locked tightly to press comes from Pennwalt Corp.'s 28
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Sharpies-Stokes Division, Philadelphia. Called the Stokes Eagle press, it is designed with a completely isolated product zone that blocks out contaminants and reduces noise. An improved dust collecting system eliminates exposure of the operator to dust and cuts material loss. With some materials, entrapped air can cause tablets to flake apart when material is compressed. So a precompression system has been designed into the Eagle press to eliminate problems with entrapped air. In process instruments, Taylor Instrument Co., Rochester, introduced a new oxygen analyzer designed for energy conservation applications in boilers, process heaters, and other combustion processes. Designated the Model 750A Servomex flue gas analyzer, it employs a zirconia-based sensor. The solid zirconia electrolyte sensor is enclosed in a small tubular furnace, which maintains the sensor temperature at a constant 800 °C to eliminate thermal gradients. An air aspirator system draws a continuous sample of flue gas past the sensor at about 300 cc per minute. The high
flow rate and a specially designed filter make the sampling system self-cleaning. Four flame traps isolate the sensor from the flue. Taylor says the instrument's fast total response is typically less than five seconds for a 90% step change within the range of 0.25 to 10% oxygen. The analyzer is accurate to within 0.02% oxygen. For measuring liquid level, Drexelbrook Engineering Co., Horsham, Pa., brought out its new intrinsically safe, two-wire True Level transmitter. The unit provides for constant, automatic recalibration to reflect changes in measured material composition, density, or temperature. Operation of the transmitter is based on a radio-frequency approach. An RF signal is applied to a sensing element. Material contacting the probe causes a change in capacitance that correlates with level. The True-Level unit is equipped with a one-piece sensing element, into which are built two sensors. One measures the material level. The other, in the lower part of the element, remains in contact with the material at all times, thus providing
Pfaudler agitator fits reactor contours
a signal that takes into account any changes in material composition, which can affect the capacitance. Applied to a Wheatstone bridge circuit, the signals produce a corrected 4- to 20-milliamp output signal that, the company says, represents the "true level" of the material in the vessel. •
Scenes from the 1981 Chem Show, New York
Dec. 21, 1981 C&EN
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