A pressurized, double contained, piped acid distribution system was installed to replace the manual filling of manufacturing process acid tanks from one gallon plastic bottles. The system delivers ten chemicals throughout the manufacturing area to over 40 points of use. The bulk chemical containers are stored in a central location, the acid dock, for safe chemical distribution control and monitoring. The bulk chemical containers, Mobile Chemical Vessels, are returned to TI's Chemical Center in Dallas for refilling. The remaining 1 gallon plastic bottles are sent to TI's Waste Chemical Center for cleaning, shredding and sent for plastics recycling.
Due to the corrosive nature of the chemicals, extreme caution was taken when the piping materials were chosen. The material had to be corrosive resistant and still meet clean room purity standards. A teflon thermoplastic material, PFA, was chosen. Nitrogen is used to pressurize the distribution system instead of the traditional mechanical pumps to prevent corrosion and reduce maintenance requirements. An extensive leak detection system runs through all the secondarily contained lines and is continuously monitored by a computer. If two consecutive leak detectors are triggered, the affected chemical system is automatically depressurized (shutdown).
The Acid Dock installation decreased bottle disposal in 1992 by 63,000 pounds (71%) from 1991. It also eliminated fugitive emissions from manually filling acid tanks. The remaining emissions from the pressurized distribution system are abated through a 95% efficient scrubber with annual emissions less than one ton per year.
Details of Reductions
Additional Information :
The $3.3 million Acid Dock installation has an internal rate of return of 16% with a 3.8 year payback. The installed safety systems, double containment, leak detection, monitoring and alarm systems have reduced employee and environmental risks. The projected savings for waste disposal are $320K.