Forbes have recently completed the design, build, installation and commissioning of a two-stage scrubbing system to reduce emissions from industrial waste processing. The system included two packed towers in series, recirculation pumps & pipework, chemical dosing equipment, extract fan, discharge stack, control instrumentation & control panels. Forbes also fabricated and installed ducting to join the new scrubbers to the client’s process by connecting to existing ductwork.
With the feedstock to the process being different from day to day, the off-gasses from the process are also varied. Therefore, it was important to allow operating flexibility, allowing for different chemicals to be used as a scrubbing medium to target as many contaminants as possible. Each scrubber was manufactured using materials compatible with a number of common scrubbing liquors (NaOH, NaOCl, H2SO4 & H2O2) and the control system was designed such that the two scrubbers could operate with a combination of any of these scrubbing liquors, using an operator-friendly touch screen.
Both scrubbers were designed such that the effectiveness of scrubbing liquor can be automatically maintained, using pH or ORP (oxidation-reduction potential) monitoring and chemical addition via dosing pumps. An automated purge of the scrubber sumps was also included to minimize salt build-up in the systems.