When the Quality of the Mixing is Important From motor fuels to breakfast foods, most industries have a mixing problem somewhere along the line. Determination of proper and practical mixing techniques is important, and frequently difficult with conventional analytical methods. But with radioisotopic analysis the evaluation of mixing efficiency* is simple, fast and economical. It is only necessary to tag one of the components of the mixture with a radioactive compound and then measure the radioactivity cither continuously or in aliquots from different regions during or after the mixing process. The oil refining industry has made use of this method of mixture evaluation most effectively. For instance, feed stocks to acrackingplantcamcintwo streams,
1. Radioisotopic compound is injected into one of the feed stocks. Stocks are blended in giant tank and radioactivity in outlet stream is followed.
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ANALYTICAL CHEMISTRY
2. Fluctuations In radioactivity persist for several hours, showing mixing is incomplete with this system.
Radioisotopic Analysis Can Help Maintain It one of varying high viscosity and one of low viscosity. These had to be blended to produce an oil stock of constant viscosity. To reduce viscosity variations the mixture was fed into a 50,000 bbl. "surge" tank and recirculated at the rate of 100,000 bbl/day. Despite this vigorous effort to attain uniformity, the stock leading to the cracker still showed abrupt and severe fluctuations in viscosity. The degree of mixing was then evaluated by adding 50 millicuries of Zr95 in an oil soluble compound to a stock inlet pipe. Radioactivity at the stock outlet pipe was measured with counters conveniently attached outside the pipe. The inhomogeniety of the mixture could then be estimated from the fluctuations in radioactivity. Mixing evaluation by radioisotopic analysis is widely applicable to a variety of industrial uses.
For instance, it has been used to measure mixing of fine dust in the air of ventilated coal mine passages, to analyze the flow of sewage and industrial waste in moving bodies of water, to detect non-uniformity of flow of liquid in refinery distilling columns, and in many other situations where it is important to know how much mixing has taken place. Designing and manufacturing high quality, dependable instruments for measuring radioactivity has been our business at Nuclear-Chicago for more than twelve years. We are a leading source for Research Quality Radiochemicals, too. From a single instrument to a complete radioisotope laboratory, we can offer you the finest and most practical equipment for your needs. We would be pleased to have you consult us on equipment needed for a progressive program in this field.
*We have prepared a technical description of procedures used in mixing evaluation by radioisotopic analysis and will be glad to send you a copy on request. Ask for Technical Bulletin No. 2.
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nuclear-Chicago CORPORATION
2 5 1 WEST ERIE STREET · CHICAGO 10, I L L I N O I S
Here is a modern, industrial analytical laboratory with NuclearChicago instrumentation caref u l l y s e l e c t e d to h a n d l e a wide range of laboratory and plant problems and to provide the ultimate in automatic sample handling, recording and read-out convenience- T h i s c o m p l e t e radioisotope laboratory is available at surprisingly low cost ($9,000—$10,000). Instrumentation systems for radioisotopic yield determination, specifically tailored to your needs, can be purchased for $2,000 or less.
For further information, circle number 7 A on Readers' Service Card, page 101 A
VOL. 30, NO. 10, OCTOBER 1958
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