In order to meet EPA compliance requirements, a global supplier of textiles needed a solution for controlling emissions of oil mist and fine particulate in their U.S. plant. The company supplies textiles for automotive interiors, which are manufactured using large, coated sheets of fabric in tenter frame ovens. The exhaust from the tenter frames were responsible for excessive visible emissions/opacity in the form of a white smoke, which included oil mist particles primarily in the sub-micron range.
Emission Control Required for Compliance
State EPA regulations for opacity (visible emissions) required emission control for compliance. The plant needed to find a proven, dependable, low-cost/low-maintenance solution to provide fine particulate and smoke elimination. The plant’s options included use of a Venturi scrubber, thermal oxidizer, or the APC Ultra High-Efficiency Filter (UHF®) system.
- Venturi scrubbers are designed to effectively use the energy from the inlet gas stream to atomize a scrubbing liquid that is being used to scrub the gas stream.
- Thermal oxidizers use thermal incineration to decompose hazardous gases at a high temperature, releasing the more benign products of oxidation to the atmosphere.
- The APC UHF® system is an automatic indexing-bed filter system that uses proprietary technology to achieve very high removal efficiency of submicron particulates and is very well suited for particulate that is oily, sticky, wet or a mixture of solid and liquid state.
Comparing the Options
The Venturi scrubber presented numerous problems the company had already experienced including very low particulate removal efficiency, of only approximately 70% on the primarily submicron mist droplets, or alternately extremely high energy costs for a pressure drop of about 40”+ w.g. to effectively control submicron sizes, as well as a resulting water treatment/disposal issue.
The thermal oxidation system was ruled out since it was the most costly capital investment and also would have required very high operating cost, in form of natural gas.
The UHF® filter system for 16,000 ACFM offered a control efficiency of 99% as well as a much lower pressure drop than the venturi scrubber. Additional advantages included simplicity of operation, extremely low maintenance, and no downtime required for filter replacement, which can be done while the system and process are running.
The Selection and Outcome
The UHF® system was selected and installed at the plant. In terms of capital cost, the UHF® filter system was the least expensive, and with the lowest operating and maintenance costs, the UHF® system had the lowest total life cycle cost of all technologies considered by a significant margin. Following installation, the UHF® system has met and exceeded the criteria for performance efficiency and provided a cost-effective solution for the tenter frame oven emissions. The system satisfies every EPA requirement including meeting the limit for visible emissions and opacity.
