Document omO8VyXxGLQdNjwkKXmrVjvo

9 The article "Getting Out the Last Traces of VCM" appearing in Chemical Week dated August 11, 1976 lists the following items: 1. Vent scrubbing with activated carbon - Tenneco. 2. Suspension slurry stripping - B. F, Goodrich. 3. Dispersion latex stripping - Diamond Shamrock. 4. Reactor cleaning - Monsanto. 5. Clean reactor (non-fouling) - Lonza. 6. Work space air monitoring - Pantasote and others. Union Carbide Corporation's participation in these items is as follows: 1. Vent scrubbing with activated carbon was evaluated as was solvent scrubbing and incineration by Mr. R. W. Martin's Engineering group. The study showed that activated carbon and solvent scrubbing were approximately the same cost. The combination of solvent scrubbing nod incineration in the steam plants appeared to offer the maximum control with the least new invest ment; thus, both Texas City and South Charleston use Ais procedure. Tenneco has not worked with activated carbon on vent streams containing oxygen, an area that seems to be fraught with peril. 2. Suspension slurry stripping offered by B. F. Goodrich has some advantages to Union Carbide Corporation. A secrecy agreement has been signed with B. F. Goodrich and samples were processed in B. F. Goodrich's pilot plant. There UCC 005082 Memorandum to Mr. Montagna September 7, 1976 Page Two was discoloration of the resin tested and vinyl acetate copolymers were not well stripped. Currently, there are no plans to pursue this techniqu further, though one business. Air Products and Chemicals, is well satis fied with the results both in terms of resin color and residual monomer content. They say that the color fault was caused by poor design of the B. F. Goodrich pilot plant and that their installation in Pensacola does not discolor the resin. 3. Dispersion latex stripping offered by Diamond Shamrock is of no interest to Union Carbide Corporation since we are withdrawing from the business. It is worth noting, however, that the proposed EPA standard limit is based on Union Carbide Corporation technology as being die best at the time the standard was proposed. 4. Reactor cleaning offered by Monsanto is simply solvent washing of PVC reactors. This is viewed as not very different from the present Union Carbide Corporation solvent washing as practiced in Texas City. Gene'ral Tire also made their solvent wash system available to all the industry at no cost. 5. Clean reactor (non-fouling) technology offered by Lonza has not been evaluated. B. F. Goodrich also has a clean reactor technology which they imply is available for licensing. These clean reactor technologies generally require recipe and product changes. This is an area for Union Carbide Cor poration R it D investigation which is not being carried forward due to the limited manpower and the press of other work. 6. Work space air monitoring offered by Pantasote and others is being followed carefully. Union Carbide Corporation developed its own system based on the automatic chromatograph and a mini-computer. The Union Carbide Corporation system appears to be very good if the proposed changes in computer programming now in progress are carried out. The Juntas ote-EOCOM system is based on the infrared Fourier transform technique. This is an expensive system ($500, 000) though very good. If Union Carbide Corporation needs a system for monitoring multiple contaminants in an area, this system has much to offer in terms of speed and accuracy. Union Carbide Corporation chose not to provide input for this article when it was being prepared. We felt that our technology was generally equivalent UCC 005083 Memorandum to Mr. Montagna September 7, 1976 Page Three and that there was little we or the industry was doing that was not generally known. Very truly yours. /c n R. N. Wheeler, Jr. i RNWJr. /pm Attachment ucc 005084 Getting out the last traces of VC Tenneco process uses activated carbon to remove vinyl chloride monomer from PVC plant gas streams. It's one of several methods producers are licensing More than a year's experience with ils carbon adsorption method of controlling vinyl chloride emissions Irom polyvinyl chloride plants has convinced Tenneco Chemicals (Saddle Brook, N.J.) that it has found the hest route. So it is setting out to license the method to others. When the cancer-causing properties of vinyl chloride monomer became known, explains Robert S. Miller, manager of polymers research, (he firm had to de velop its own technology to control emis sions. Now it is marketing the know-how in the U.S. and in European countries that are following the U.S. lead in setting stringent emission standards. The firm is just one of a number of U.S. producers that have developed li censing packages in an effort to recoup part of the millions they have spent to de velop the new technology. . II.F. Goodrich is licensing its steam_stripping process, which removes VCM from PVC suspension resins. Diamond Shamrock has developed a proprietary technique tor removing residual VCM . Iron"PVC dispersion resins. Monsanto, has been licensing its PVC reacttmlcan.ing know-how for more than a year. I.onza (Basic/Switzerland) is offering a procedure lor preventing suspension resin polymer huildup on reactor walls. And several others have developed in strumentation to monitor the amount of VCM in the atrand in PVC. Thirsty Carbon: Tenncco's developmen! is aimed at recovering the residual ~VTM~ in vent gas streams (CM*. Sept. IS, 1974. p. 66). A unit built by Chemical De sign (Lockport, N.Y.) was installed at Tenneco's PVC plant in Pasadcnn. Tox in early 1975. A year's experience with the equip, ment, says Roy T. Gotiesman, associate director of research and development, shows that less than 4 ppm. ol vinyl chlo ride monomer is escaping in the adsorber effluent stream. During that time, the ac tivated carbon in the unit has undergone more than 1,300 adsorption and regener ation cycles. That makes it good enough to meet the proposed Environmental Pro tection Agency standard of 10 ppm. Moreover, after 10 months of contin uous service, samples of carbon with drawn from the adsorber showed that it retained 90% of its original adsorptive ca pacity. Further, there was no evidence of vinyl chloride polymerization in the ad sorption unit or within the carbon Trouble Spots; Aside from leaks, which manufacturers try U> keep to a minimum, there aic several points where VCM van escape in the atmosphere: at the reactor, the slurry tanks, and equip ment pulgc streams. PVC is made primarily by either sus pension or emulsion polymerization tech niques. Generally, in these processes VCM and the polymerization initiator are dispersed in water by the use of sus pending or emulsitying agents. The poly merization temperature is selected to ob tain the desired molecular weight. But not all of the vinyl chloride is converted into PVC. Usually 17-20% of monomer that does not react remains at the end of the polymerization cycle. Much of that can be recovered and recycled to the front end of the process. But as much as I, 1 ,i i ii <i l. i .; . i , I TENNECO S GOTTESMAN: New process cuts PVC plants' VCM loss to below 4 ppm. 4% VCM can remain in the PVC slurry from the reactor. That can be removed by specialized Stripping techniques, such ns the ones Goodrich. Diamond Shamrock and Tenneco now offer. Residual VCM from that cleanup phase is one of the potential sources of feed lor the carbon adsorption step. Another source is the slurry tanks, where operators Hush air or nitrogen through the vapor space of the tank to keep VCM concentrations down and pre vent a flammable mixture from forming. Depending on the level of stripping of the slurry downstream. VCM concentra tions in the nitrogen purged may reach 15 mol percent. f Various equipment in the process is also purged with inert gar to reduce the explosion hazard and to remove the last traces of VCM. These off-gas purge streams generally contain 10-30 mol per cent vinyl chloride. New Twist: Vinyl chloride has been around long time and so has activated carbon. But up to now, researchers have worked with pure monomer. Tenneco's contribution has been to make the pro cess work with recovered vinyl chloride, savs Gotiesman. He explains that this material can contain residual initiators, catalyst fragments, and suspending agents, so that it is prone to polymerize and foul the carbon system. Making the process work is a matter of selecting the right operating conditions and the right type of activated carbon. Another method of scrubbing VCM from stack gas. called oxyphotolysis, has been investigated by Rnhintech of Fort Worth. Tex. (OF Tcchnnlopv Sewsleiitr. Julr 9. I97J). The lirm says it is still eval uating the economics of installing the unit, which so far has not been used com mercially. Although carbon adsorption is the pro cess that Gotiesman believes will attract the widest interest, the company is arm ing itself with a variety of other tech nology. "We have filed 13 paten! appli cations on widely differing subjects." says GiXtcsman. "They include a spray appa ratus lor cleaning I'VC reactors, processes lor removing Vt M front suspension and emulsion processes, the destruction of VCM by ozonoivsis and the removal of niunonicr front dispersion latex by spar ging" If others' experience is any indication, there is a big demand for the know-how. B.F. Goodrich Chemical says it has signed agreements with six corporations in Sweden, Italy. Japan and ihe U S. for its suspension-resm stripping technology. Diamond Shamrock became a licensor in March, offering its proprietary tech nique for removing residual VCM from August 11. 1976 CHEMICAL WEEK 39 ucc 005085 You can have plenty; get it fast! Aminate reacts with acids tb generate carbon dioxide and pro duce solutions of the correspond ing salt. It's used in the manufacture oftetrazene, an ingredient for small arms primers. Further applications; in photo graphic emulsions, azo dyes, depilation of animal skins, textile softening agents, flameproofing agents. Also as a blowing agent in i manufacture of foam as a vinyl sta bilizer, and in the preparation of aminoplast resins. Let your chemical imagination roam. Find all the uses you want, because we have all the Aminate you could want. Available as a fine, white, odorless crystalline powder. Delivery is fast. The price is right. For full details, write today to the IMC Chemical Group, Inc., Sobin Ffcrk, Boston, Mass. 02210. imc 18 CHGfflICfll GfiOURlnc CSC INDUSTRIAL CHEMICALS DIVISION A iiisumy a) iwtHOanl t Cnmur* Corpcnon 36 CHCMVtt WCtH August ||, 1976 1 '' kJ ` " '^J dispersion rc'mv Different techniques are required for the two systems because of differences in particle sue. The company explains that in the sus pension process, monomer droplets sus pended in water typically produce PVC particles ranging in size from 90 to 130 microns. In the dispersion or emulsion process, a colloidal dispersion of mono mer droplets creates PVC particles aver aging 0.S micron in size. These smaller panicles are more sensitive to heat and mechanical disturbance than suspension resins, thus different technology is re quired. Says Diamond Shamrock, "We are us ing it ourselves. We have a number of people seriously interested, including some from outside the U.S. We do not at the moment have any licensees. But it is a relatively new offer." It seems doubtful that anyone will reap a (sandal bonanza from the new technotogy. Rather, licensors see their cfTort as one of trying to recover part of their development cost. Diamond Shamrock adds: "Licensing this kmd of technology is not going to be a gnd money-maker for anybody, as far as vc can see, once you put the income geaoned up against what it cost to dcwebp it in the first place. We hope we will hr able to defray our developmental cona-diat is, spread them out through the mdiumy" Insight into energy A sew 900-page United Nations study of emgy use has turned up extensive data' the use and distribution of commcron# energy since 1950. Among the Bndirp: 11a U.S., with 5% of the world's popdMion, used 30% of the world's commereid energy in 1974, compared with 45% m 1950. Its per-capita gasoline eontumptm was nine times the world aver age. " Ke U.S.S.R., the world's secondlarged user, increased its share from I l,5%iin 1950 to 16.6% in 1974. Clina and Japan are the third- and foorfMhrgest consumers, respectively. Chinnsill relies mainly on solid fuel. Ja pan a leading importer of all types of energjt. The sport updates earlier studies on cumuncial energy production, trade and oonaunption and includes preliminary data n the'production of primary fossil foeIsto 1975. It nailable from the UN Sales Sec tion (Bkw York) for S30. ucc 005086