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Hydrochloric Acid Recovery
ChE in Action: Beta Control
With hydrochloric acid being used to treat the surfaces of many metals along with many other applications, being able to effectively recover the acid can yield significant financial rewards. Galvanizing, steel pickling, and electronics manufacturing are some of the largest users of hydrochloric acid. Beta Control specializes in recovering hydrochloric and other acids through their complete line of acid recovery systems. Byran Cullivan, president and founder of Beta Control, reports the following benefits of hydrochloric acid recovery:
Description of Process
A centrifugal pump forces the spent hydrochloric acid through a pre-filter and into the evaporator loop, comprised of the main exchanger and the separator. In the evaporator loop, the spent acid is heated to vaporization. As the solution increases in concentration, the temperature increases in the loop. Forced by expansion, the acid and water vapors are driven from the separator, through the acid condenser, and into the recovered acid tank. The concentration of acid is controlled in these steps to return excellent quality acid to the pickling tank. When the proper solution temperature/concentration is reached, a ferrous chloride concentrate is withdrawn slowly from the loop and transferred to a storage tank for sale as a solution or for conversion into a solid crystal. Remaining water vapor continues its journey through the final condenser where it is sub-cooled and scrubbed of residual acid vapor. Any final condensate is reused as rinse water in the pickling process or is returned to the pickling tank with the concentrated acid.
The following results of Beta Control's Acid Recovery Systems appeared in a report from the U.S. Office of Industrial Technologies:
The acid recovery system delivers significant savings. Currently, a typical small- to medium-size steel manufacturing plant spends $14 per ton to clean its products. With Betas recovery system, manufacturers can slash that cost to just $3.40 per ton. The system costs about $250,000. Beta estimates a 73 percent internal rate of return, with a payback of 1.4 years for a one-gallon-per-minute system. Moreover, acid recovery requires minimal labor, and the life expectancy of a recovery system exceeds that of a conventional acid neutralization system by at least 3 years.
The recovery system also saves energy. Steam consumed at about 3 cents of energy per gallon of acid processed is needed to drive the reaction that recovers the acid compared with about $3 per gallon to neutralize acid, the process currently used to ready acid for disposal. Additional energy is saved by eliminating the acid-neutralization step and the need to transport and dispose of waste. An HCl acid recovery system operating at full capacity (25,000 liters processed per day) is estimated to save about 24 billion Btu per year over conventional transportation and disposal energy use. Since 1993 the systems operating in the United States have saved over 280 billion Btu.
Since 1993 Beta has refined its recovery process and commercialized its system. Early users of the HCl recovery process are located in Saukville, Wisconsin, Long Beach, California, and Tampa, Florida. Beta has sold six systems in the United States as well as nine others in Europe, Asia, Mexico and the Middle East.
These companies are recycling their pickling acids and are also venturing into the agricultural product market. The ferrous chloride by-product of the recovery process can be sold for up to $100 per ton. Cullivan noted that "one of our customers who spent over $8,000 per week for the disposal of spent pickling acid now sells the ferrous chloride by-product from our system for a net profit of $2,000 per week after operating costs."
According to Beta Chemist, Fred Thiem, the companys recovery system was not developed to create revenue for its clients. "Our system was created to help find a more ecological way to deal with spent acids. The real benefits of this technology are process control and cost minimization," he said. The installation of this equipment in Wisconsin has lead to two separate pollution-prevention awards presented by the state.
Read More About Hydrochloric Acid
Beta Control Systems, www.betacontrol.com
"STEEL Success Story", a report from the U.S. Office of Industrial Technologies