Progress 05/15/09 to 01/14/10
Outputs
OUTPUTS: Task 1: Syntheses of adsorbents for ethylene removal were performed using various literature preparation methods. Surface areas and pore sizes were obtained for all adsorbents. Task 2: A reactor system was designed and constructed which enabled testing of a fixed bed of adsorbent contained in a quartz tube within a Pyrex sleeve that was capable of being filled with coolant. The temperature of the coolant could be controlled between -10 and 100C. Feed gas flows were controlled via mass flow controllers and humidity was added to the line via a bubbler placed prior to the reactor which could be cooled with an ice bath. Sample ports were place both prior to and immediately after the adsorbent bed and samples were taken and run through a G.C. equipped with a 3' Porapak Q column. The total concentration of ethylene was 20 ppm in air but could be reduced to as low as 2 ppm via mixing with another independent air line. In all a multitude of experimental runs were performed on 20 different adsorbents under both dry and humidified ethylene/air streams containing between 2 and 20 pm ethylene. Task 3: The most promising adsorbents were run through a series of adsorption/regeneration cycles under both dry and humidified ethylene/air streams and also tested under ethylene/air streams within which the ethylene concentration was cycling between 5 and 10 ppm over time. Both of our primary adsorbents were also re-synthesized with various binders in hopes of adding additional strength and support. Several significant kinetic studies were also performed to discern the effects of both changes in concentration of ethylene and changes in flow rates. Task 4: Design of a small prototype was designed based on the initial results obtained in Phase I and a general economic feasibility study was also completed. Eltron Research & Development also had discussions with Ethylene Control Inc. (Selma, CA) prior to the Phase I project, during the project, and upon its completion in January 2010. Ethylene Control deals in potassium permanganate packets which are disposable and help remove ethylene in confined spaces. The ability to offer an ethylene removal system which can be regenerated is of real interest to Ethylene Control and they have agreed to field test a prototype unit to be produced in the proposed Phase II and also aid Eltron in advancing the system to market should we produce an "economically compelling technical solution". Ethylene Control has also offered advice on various performance targets which would be crucial to the commercial appeal of any new ethylene removal system. These suggestions helped guide the development of the workplan in the Phase II proposal which is expected to help speed the development of the prototype and ultimately the commercial product. PARTICIPANTS: Jesse W. Taylor - Primary Investigator Dr. Taylor=s role in this program was as the primary investigator and as such he provided the research direction, performed the majority of the data evaluation, and wrote the majority of all reports. Erick J. Schutte - Secondary Investigator Dr. Schutte provided assistance in all areas of the project including synthesis, characterization and testing of materials, data logging and evaluation, and report writing. Porntip Dubuisson - Technician Mrs. Dubuisson was the primary laboratory researcher on the project whose focus was synthesizing, characterizing, and testing all materials, logging all pertinent data, and recording findings in official notebooks. Dave Biswell - President of Ethylene Control, Inc. (Selma, CA.) Mr. Biswell currently oversees a company that specializes in ethylene removal within the fruit, flower, and vegetable industry. The investigators on the project were in contact with Mr. Biswell before, during, and after the Phase I project and were provided with crucial information about the industry including various needs and issues. Mr. Biswell also provided a list of key research targets that needed to be met in order for a new ethylene removal technology to be viable in the commercial market. This information was used extensively during the development of the Phase II proposal Work Plan. TARGET AUDIENCES: Companies and individuals within the horticulture commodities and adsorbents markets, including produce and floral shippers and distributors. Companies and/or individuals who specialize in providing ethylene removal solutions will also be prime targets for technology licensing. PROJECT MODIFICATIONS: The original project plan was to develop regenerable "catalytic" ethylene removal materials. However, the catalysts developed early in the project did not produce the desired results (i.e., they did not remove 100% of a 20 ppm stream of ethylene and were not very regenerable). We then turned our focus to sorbents and found several which met the necessary criteria, both from an adsorption and regeneration standpoint, that we had put in place to determine if a material was deserving of optimization. This minor change in material development was reflected in the Phase II being titled "Regenerable Ethylene Removal" after an e-mail exchange with the USDA project officer was completed addressing the issue.
Impacts
In order for a new ethylene removal system to be considered viable in the current marketplace it needs to be able to function in humid conditions and under variable ethylene concentrations while being capable of removing 100% of low ppm levels of ethylene for an extended period of time. Any sorbent that can be regenerated also needs to exhibit high, steady, continuous activity over numerous regeneration cycles. During Phase I, Eltron developed regenerable adsorbents for ethylene removal under humid conditions and finished preliminary designs of a prototype ethylene removal device. Data collected during the Phase I showed that Eltron's primary adsorbent was capable of removing 100% of the ethylene in a 5 ppm ethylene/air stream for over 24 hours in dry conditions and for 2.5 hours in humid (60% relative humidity) conditions. Changes in ethylene concentration during experiments did not have any negative effect on the ethylene removal ability of the adsorbent. The adsorbent was also shown to be regenerable in both dry and humid conditions through multiple cycles with no substantial loss in activity. Financial assistance through the United States Department of Agriculture, and more specifically, the Cooperative State Research, Education, and Extension Service was crucial in the success of the Phase I. The assistance allowed us to purchase raw materials for test reactors and sorbent synthesis, fund a technician who could run the experiments and log data on the project, and fund a primary investigator to interpret the data, evaluate results, and make decisions moving forward.
Publications
- No publications reported this period
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