Regenerable Ethylene Removal

Fresh fruit, vegetables, and flowers are transported and stored in refrigerated containers. As the produce ripens, ethylene gas is produced, which further ripens the product and can lead to premature spoilage. Most fruits and vegetables emit ethylene gas which promotes ripening. Certain species, such as apples and bananas, produce more ethylene than others. Elevated ethylene levels can significantly reduce storage time; concentrations as high as only 1 ppm can destroy an entire container of produce in one day. The current ethylene removal industry uses single-use potassium permanganate adsorbent blankets or sachets, or a removal device that has a limited lifetime (38 months). Other devices that are on the market or currently being developed include biofilters, ozone generators, and photocatalytic and electrocatalytic devices. Disadvantages of these devices include very strict storage requirements, the potential of contamination by the ethylene-destroying bacteria, the need to employ complex systems to produce ozone, and high manufacturing costs of the photocatalytic device and nanoporous gold electrocatalysts. The goal of this Phase II program is to optimize the adsorbent, complete the design and fabricate a bench top, multi-bed unit. The research will be focused on long-term testing (months instead of days), extended testing under high humidity conditions, testing at concentrations below 1 ppm, testing mold spore kill efficacy of the adsorbent, and evaluation in atmospheres with fluctuating concentrations of ethylene. Engineers at Eltron will be called upon to finalize the design and subsequently build the multi-fixed bed system, which is optimized towards our primary adsorbent and the optimal conditions found during the research. Major benefits of the new system include the ability to regenerate the adsorbent (long lifetimes without having to replace the active species), use of relatively inexpensive materials (no platinum, ruthenium, or gold), and a simple device design, making it inexpensive to manufacture and simple to use. The low maintenance design of the device will allow for increased storage time and reduce spoilage, resulting in reduced costs to all parties along the supply chain - grower, transporter, distributor, and consumer. A renewable ethylene adsorption system would be able to reduce ethylene concentrations within refrigerated dock-side storage containers, refrigerated train cars and grocery store storage refrigerators at minimal long-term cost, and would eliminate the cost and hassle of frequently changing disposable adsorbent beds. By the end of the Phase II program, a prototype low-cost device for the removal of low concentrations of ethylene will have been fabricated, evaluated in a lab setting and in a real-world setting by Ethylene Control Inc., who has already expressed interest in this technology. During Phase II, partnerships for the commercialization of the device will be initiated in order to bring the product to market as soon as possible.