Removal and Recovery of Methyl Ethyl Ketone (MEK) Vapor Emissions by Carbon Fiber Adsorber-Cryogenic Condenser

摘要

The Clean Air Act Amendments of 1990 mandate the reduction of emissions of hazardous air pollutants (HAP). Activated carbon fiber-cloth (ACFC) offers promise as a superior adsorbent to remove and recover organic HAP from gas streams. This study designed, built, and tested a second-generation system with an improved adsorber using methyl ethyl ketone (MEK) as the organic pollutant. Total flow rate of the bench-scale system was 5 Lpm with the gas stream containing 1000 ppmv MEK. Breakthrough times ranged between 11.9 and 12.9 hr. Throughput ratios of 86.9 percent were achieved. Electrothermal regeneration times were approximately 1 hr at 100W. It was shown that increasing the adsorption bed's dry-bulb temperature by 10 degrees C can cut adverse effects of treating high humidity gas streams in half. The system was automated to demonstrate continuous MEK adsorption, desorption, condensation, and recovery. Overall removal efficiency during continuous operation was 99.9 percent by mass. The study's preliminary design and cost analysis for a pilot-scale system estimates a cost of $60,000 for a flow rate of 0.5 m3/min and a concentration of 1000 ppmv. An economic analysis of a proposed full-scale system shows that a process recovery cost of $2/kg of MEK is achievable.