An East Coast chemical plant that manufactures phenol, acetone and alphametyl styrene from cumene planned to install an air pollution control system to control the volatile organic compounds (VOCs) emitted during their chemical production process. Phenol is consumed internally as an intermediate chemical while acetone and alphametyl styrene are sold off. Once the chemicals are produced, they are shipped to another plant to make carpet fibers. This plant already had a carbon recovery system in place, but needed a system to control the low concentration residual airstream from the carbon recovery system.
After thorough vendor evaluation, the plant selected and contracted Anguil Environmental Systems, Inc. to solve their VOC emission problem. The combination of VOCs in the airstream and their low concentration made catalytic oxidation the ideal technical choice. Plant engineers had concerns that an oxidation system might have an adverse effect on the precise pressure and volume control required in their production process. Anguil's experience and success with chemical process applications provided the plant personnel with the confidence that catalytic oxidation was a viable solution.
An Anguil Model 650 forced draft catalytic oxidizer, rated for 65,000 SCFM (102,512 Nm3/Hr), was selected to process the airflow from up to 25 point sources of emissions. As always, Anguil's engineering staff worked closely with the customer throughout the design and manufacturing processes to ensure that the system precisely met their requirements. The system was sized to provide 99% destruction efficiency and 70% thermal energy recovery. The reactor section contains two parallel catalyst beds; each bed oxidizes half of the incoming airflow. The catalyst converts VOCs into carbon dioxide, water vapor and thermal energy. The thermal energy is then reclaimed by utilizing a primary heat exchanger, thus reducing the system operating costs.
In order to address the concern of the precise pressure and volume control required for the customer's production process, a four module heat exchanger was manufactured. By using a greater plate thickness, as well as fabricating 'ribs' and 'dimples' on the plates, a pressure differential of 87.5 w.c. was sustained.
The plant's process operates 24 hours a day, 7 days a week. The oxidation unit is required to run continuously to accomodate the chemical process. The control system was integrated into the customer's control system and redundancy was designed into the most critical control items. A difficult pollution control issue was solved by Anguil, resulting in another of their more than 800 satisfied customers worldwide.