TECHNOLOGY
Chem Show Spotlights Process Equipment, Instruinc .ation Among offerings on view were high-performance filters, triboelectric velocity meters, and glassed steel vessels for high-temperature applications James H. Krieger, C&EN Washington
When the 42nd Exposition of Chem ical Industries—the Chem Show— took to the floor of the new Jacob K. Javits Convention Center in New York City early this month, it re tained one characteristic of its Coli seum days: As a showcase of the state of the art in commercial pro cess equipment and instrumentation, it remains a valuable and informa tive resource for its many visitors. This year's exhibit featured a wide range of products. For those seek ing out the innovative, the offer ings included new concepts in fil tration equipment and in velocitymetering instrumentation. And for those visitors interested in equip ment for use at extreme process con ditions, there were advances in glass and polymeric coatings. The new concept in filtration equipment comes from 3M, St. Paul, Minn., in the form of a h i g h performance liquid filter bag. Called the Series 500, the bag is made in four models to handle filtration of particles in the 1- to 40-μπ\ range. Full-scale production is slated for March or April, but bags are avail able now on a test basis. Design of the bag is such that it provides more than 30 sq ft of filter media wrapped into the 35 layers that make up the bag construction. 3M says that this figure contrasts with standard bags that have 4.4 sq ft, or typical cartridges having 0.65 sq ft, of filtering surface area. The 16
December 21,1987 C&EN
Series 500 bags are 32 inches long and 7 inches in diameter to fit widely available filter bag housings. Apart from stainless steel rings and clamps, the bags are made en tirely of polypropylene. To provide for a fluid flow management sys tem within the bag, 3M employed three types of media layers. Nine inside layers are made of very fine melt-blown microfibers, each sandwiched between coarser nonwoven mat layers. The microfiber bypass layers capture particu late materials but have openings that allow fluid to pass through. As it flows through the filter, the fluid is uniformly distributed by the coars er mat layers. The openings change in size, becoming smaller in diame ter in successive layers, to evenly distribute particulate material for even loading of the bag. The by pass layers prevent the filter from being clogged too early, 3M ex plains, and the coarse distribution layers ensure high loading capacity by distributing fluid so that all of the filtering material is used. The
outer 15 layers of the bag are final filter layers and are also made from very fine melt-blown microfibers. 3M has applied for patents on the combination of bypass and trans port layers. It also has applied for patents on the seamless construc tion of the bag. Seamless construc tion, the company says, prevents leakage through the filter media, thus allowing for high efficiencies. The velocity-metering instrumen tation is a development of Auburn International, Danvers, Mass. The new Model 3000 instrument, based on the company's triboelectric tech nology, measures velocity of solid particles in plug flow and pneu matic transport systems. Triboelectricity is the name giv en the electrostatic p h e n o m e n o n that occurs when two materials col lide or are rubbed together, causing a transfer of charge from one mate rial to another. The magnitude of the charge is minute, but it is mea surable as current, Auburn explains. Auburn notes that two approaches can be used for quantifying and
Filter bag uses three types of media for fluid flow management CIRCLE 10 ON READER SERVICE CARD ·
PEMMAU.
Organotordcs ORGANIC CHEMICAL NEWSLETTER FROM PENNWALT
Pennwalt's MSA Outperforms PTSA and Sulfuric Acid as a Catalyst for Esterification Reactions For years, resin manufacturers
the benefits of MSA over p-toluenethat supply paint and coating sulfonic acid and other existing companies have relied on sulfuric esterification catalysts. acid as the priWÊMJV/Jk Due t 0 i t s nonmary catalyst for oxidizing ability, esterification. In • MSA consistentthe mid-1970s ly helps produce manufacturers esters with lightbegan to stress er color than higher yield, less those produced tar and decreased using sulfuric discoloration. acid or arylsulThey turned fonic acids. In their attention to situations where alternative cataoxidation could lysts such as interfere with or change the esterPTSA, organoification reacmetallic salts and tion, MSA is ion exchange MSA: the esterification catalyst of choice particularly resins in order advantageous. to meet these demands. More recently, industrial users As a cost-cutting chemical, have discovered an esterification Pennwalt's MSA is a front-runcatalyst that offers excellent rening catalyst. MSA can be used sults at a significant cost reducat lower weight concentrations tion. The chemical: Methane Sul- than its competitors because of its low molecular weight. As a fonic Acid (MSA). The exclusive result, in many cases, industrial U.S. manufacturer: Pennwalt. users can perform esterification MSA is a chemical with unreactions at a lower catalyst cost. precedented characteristics and advantages. In addition to being Since MSA gives better phase a strong acid, MSA is non-oxiseparation of acid from the findizing. This combination makes ished product, it increases the it remarkably effective as a percent recovery of acid for recycling. Better phase sepacatalyst in the preparation of ration often results in increased acrylic ester monomers. yield—and increased yield Detailed studies conducted by Pennwalt Organic Chemicals R&D means increased profits. The advantages of using MSA personnel have demonstrated
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don't stop there. In some reactions, MSA allows you to operate at a lower temperature or with a shorter reaction time, thereby saving energy. It can improve overall yield by eliminating side oxidation reactions. Other key benefits to using MSA as an esterification catalyst include faster reaction time, less tar and side products, decreased waste disposal and ease of handling. In a phrase: as an esterification catalyst, MSA offers all the advantages that today's industrial labs are looking for. Other processes that are actively using MSA include the preparation of saturated mono-, di-, and triesters, and cellulose acetate. MSA has also recently been used both as a catalyst and a solvent to make bis(p-hydroxyphenyl) ketone—an intermediate for dyestuffs, polymers and UV absorbers. MSA is a multifaceted chemical with seemingly endless potential. MSA is available from Pennwalt as a 70 percent solution in water or as an anhydrous grade. For technical data or sample information, check the reply card or call the Pennwalt Organic Chemicals sales office nearest you. •
INSIDE NEWS: page Dimethyl Disulfide 2 High purity alkylamines 2 Pentaphen 67 3 Alkyl Alkanolamines bulletin 3 What's New 4
ORGANOTOPICS FROM PENNWALT
DMDS: A Preferred Agent For Catalyst Presulfiding Dimethyl Disulfide (DMDS) is now available from Pennwalt as the result of a multi-purpose plant coming on stream with an available capacity of more t h a n 10 million pounds annually. This plant, based on proprietary Pennwalt technology, is a continuing example of our commitment to maintaining and expanding our leadership position in mercaptan and sulfide capacity and technology. DMDS is considered by many petroleum refiners to be the preferred agent for the presulfiding of hydrotreating and reforming catalysts. Experience has shown that presulfiding with a labile organosulfur compound such as DMDS significantly improves the initial activity and increases the useful cycle length of nickel/molybdenum (NiMo), cobalt/molybdenum (CoMo), nickel/tungsten (NiW) and cobalt/ tungsten (CoW) hydrotreating and hydrocracking catalysts relative to presulfiding with native sulfur or H 2 S. The relatively low decomposition temperature and high sulfur content of DMDS allow presulfiding to be carried out efficiently and cost-effectively. Because lower presulfiding temperatures can be used, the risk of excessive heat buildup and catalyst deactivation is minimized. Ease of handling is improved with DMDS because of
Product
% Contained Decomposition Sulfur Temp°F.
Boiling Point ° F .
Flash Point Toxicity LC 5 0 Closed C u p ° F . Inhalation
dimethyl disulfide (DMDS)
68.1
392
230
dimethyl sulfide (DMS)
51.6
482
97
