As expressed by Bill Frost, of Chemron: “Chemronmaintains a strong environmental commitment, which views regulations as a challenge rather than a burden. It’s important for the chemical industry to go beyond today’s specific control regulations, and to look ahead, not only to where the regulations will be in a few years, but where we should be.”
He believes that complex problems should be considered long-range, thereby providing time to make orderly adjustments to process and treatment methods. Compliance then becomes part of the process rather than an externally-imposed hardship.
Seeking a profitable solution
Design criteria for the sought-after emission-control system included variable flow rates from 60-240 scfm, with various concentrations of hydrochloric acid and inert gases. Gas stream temperature runs about 110 F. Specifications for the control system, as provided to 5 companies, included 2 criteria considered to be essential. A very low emission level (5 ppm) had to be achieved, and hydrochloric acid had to be collected in salable form (concentrations of 31.5 to 32%).
The system purchased by Chemron uses 2 jet venturi scrubbers in series to intimately mix the airstream and scrubbing liquid, followed by 2 packed towers to remove residual hydrochloric acid. Height limitations required the use of two shorter towers rather than a single tall tower. Jet venturi fume scrubbers were selected because they can handle load fluctuations very well, and the 2 units in series can recover more than 98% of the hydrochloric acid. The venturis also
provide back-up for each other, increasing the safety factors involved. The units are nonmetallic for corrosion resistance, with fiberglass-reinforced plastic bodies and PVC spinners.