VOL.6. No. 10
THECHEMISTRY STUDENT
1781
A MINIATURE CONTACT-PROCESS SULFURIC ACID PLANT* S. C. DENNIS,GIRARD COLLEGE, PHILADELPHIA, PENNSYLVANIA In preface to the description herewith presented, I may say that the industrial applications of chemistry have always been especially stressed in our courses a t Girard College. As a means of awakening student interest along this line and of facilitating instruction in the solution of practical problems, our more advanced students are assigned projects dealing with commercial processes. These projects involve studies of the technical and scientific literature on the respective topics assigned and the preparation of reports which are delivered before the class. Drawings necessary for semi-works scale plants are made, and, finally, actual models of such equipment are constructed in the shops. With the exception of the fact that some of the actual construction work is done in regular shop time, these activities are carried on largely as extra-curricular and recreational projects. Naturally, student interest is an essential to the successful operation of such a program and a special effort is made to assign individuals to problems which particularly appeal to them.
THEASSEMBLED PLANT The blower, gas-burner, and electrical heating unit for the contact tower arc not shown. I n our work, as in actual industrial practice, it often happens that the plant originally constructed leaves something to be desired in the way of successful and convenient operation. Hence, most projects do not automatically become "dead" after one assignment. Further research and development work is nearly always possible.
* Edilor's Nole: This article describes one of a number of models designed and o n structed by Prof. Dennis' students, and is the first of a series of descriptions which he has agreed to prepare for us.
The Sulfuric Acid Plant What I have just said is true of the sulfuric acid plant here described. Had I not the assurance of the editor that descriptions of models which offer opportunity for further develop5 ment are equally as desirable as accounts of perfected apparatus, I should, per:haps, have hesitated to accedk to his request for $ the preparation of the present article. In this account, 8 therefore, I shall indicate some of the more outstand6 ing improvements which would be desirable in the present apparatus.
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Materials and Details of Construction
The accompanying diagrams, together with the *g photograph, convey most of 5 the essential facts as to dimensions and details of construction, so that it is scarcely necessary to repeat 4 all such information here. 5 A few additional remarks, however, may be helpful. The containers are made of large-sized pipe of a good grade of cast iron, probably bordering on steel in composition a n d properties. The connecting piping is also of iron. Valves and fittings were all made by handin our own shops.
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The baffle plates in the mixer are of I// sheet steel, perforated alternately at top and bottom by a number of ' / r " holes, as indicated by the dotted lines in the diagram. This design insures thorough mixing of the gases. The baffle plates are inserted into slots cut in the inner walls of the mixer. The shelves in the contact tower are '/a"-thick discs of steel, perforated by '/I" holes. The shelving is designed so that it may be handled as a unit-as indicated in the diagram. The electrical heating unit for the contact tower is not shown. We are still experimenting with that, and with means for accurately determining the temperature a t various points within the tower. It seems probable that we shall have to construct the tower of smaller pipe, before we shall be able to maintain it at the reasonably constant desired temperature of 40&450°C. . Charging and Operation At present the burner cannot be continuously charged. We have employed the rather unsatisfactory expedient of unscrewing the burner top, introducing a small charge of sulfur, and reclosing the apparatus. A better burner is now being designed. Air for the burner may be furnished either from laboratory compressed air lines or from a motor blower. One of our students is a t present repairing an old vacuum cleaner and converting it into a blower. Heat is furnished by a Fisher burner. Acid is introduced into the cleaner and the'two absorbers by removing the respective connecting pipes. When necessary these containers are drained by siphoning. We are now constructing valves to facilitate these operations. The contact mass is prepared by spraying fused Epsom salts with platinic chloride solution and heating. Lumps of the material so obtained are distributed upon the shelves of the contact tower as they are lowered into place. Conclusion All of the planning and construction work represented by this model was done by the students themselves, and further improvements are being worked out by them. There seems to be no reason why chemistry clubs or other groups, or even individuals, cannot work out similar miniature plants with little or no assistance from their instructors, if they are willing to undertake the necessary amount of really fascinating study, experimentation, and labor.
