A large consulting and contracting firm owns and operates several ex-situ Thermal Desorption Units (TDUs). Each single-load Thermal Desorption Unit has the capacity of desorbing 15 tons of soil per hour at a temperature of 400°F - 900°F. These Thermal Desorber Units have been designed to operate on both chlorinated and non-chlorinated RCRA, CERCLA, and private industry sites. Since each TDU has the flexibility to operate on hydrocarbon and halohydrocarbon sites, the selected pollution control system had to share this flexibility. Also, due to varying environmental regulations throughout the country, as they relate to HCL discharge limits, the selected pollution control system had to eliminate any HCL generated through oxidation of chlorinated compounds. Finally, the controls systems portability was a crucial factor since this contractor's profitability is based upon how quickly the system is mobilized, the site is remediated, and the unit is demobilized for movement to the next site.
The lack of inexpensive natural gas feeds at many sites, and therefore the required propane fuel source, lead the customer to believe that the 1600°F - 2000°F operational temperature of a thermal incinerator would lead to unacceptable fuel costs. After examining various equipment capital and operational costs, this consultant/contractor recognized the benefits of a Chlorinated Catalytic Oxidizer (Chloro-CatTM) coupled with an HCL Scrubber. After a thorough technical evaluation and bid process, GLOBAL TECHNOLOGIES was selected to solve their VOC problem by providing a mobile treatment package.
Global's experience in the chlorinated catalytic oxidation and HCL treatment prior to the initiation of this project was extensive. At this point, Global had installed over 30 such systems to treat chlorinated streams from Soil Vapor Extraction (SVE) and airstripper sites. This experience proved invaluable in designing and implementing the proper solution. Each rotary kiln TDU could be expected to exhaust up to 5,000 SCFM of desorption air at a temperature between 400°F - 900°F and a chlorinated VOC concentration of 3,000 ppmv. Utilization of a high temperature baghouse on the TDU skid removed concerns associated with dust or dirt plugging of the monolithic catalyst cells.
Global utilized an induced draft FRP fan on the backend of the treatment package due to the high temperature, highly saturated exhaust from the TDU. As with all Global chlorinated catalytic systems, a 316L stainless steel shell and tube heat exchanger was installed in the 316L stainless steel reactor. The chlorinated catalytic system was designed to provide 99% destruction efficiency at a temperature of 500°F - 850°F to reduce auxiliary fuel usage. Safety systems were installed to ensure no HCL condensation or system corrosion.
The 50' drop deck trailer, upon which the chlorinated system was mounted, also incorporated a Liquid Propane Vaporizer, a storage area for equipment transport, and an HCL Scrubber capable of 99.9% HCL removal in both caustic and pure water mode.
The most recent compliance testing of this turnkey package demonstrated over 99% destruction of all compounds. The result is another satisfied Global client.