Progress 09/01/04 to 08/31/07
Outputs
OUTPUTS: The key technical objective for this Phase II SBIR program has been to develop the CMS membrane technology and performed pilot scale testing of the OD process for concentrating grape juice. Hollow fiber supports have been in-line coated with CMS's thin non-porous perfluoro-membrane material. The in-line coating process was developed for hollow fiber passing from a feed spool at a fixed tension and speed, immersed in a polymeric solution capable of forming a membrane coating on the hollow fiber substrate, passed a deionizing blower, and rolled on to a take-up spool. Variables were optimized for the in-line coating process: solvent, polymer solution concentration and viscosity, fiber winding speed, fiber porosity, drying time, and drying temperature. We have made thinner membranes, increasing the dewatering rate of the OD process. This work has led to membrane modules with significantly improved performance for use in osmotic distillation (OD) and in a practical process for concentration grape juice without losing flavor and the other valued sensory trace chemicals. The value of the OD process has been demonstrated, though early in our experience with this particular piece of equipment. Funding was not available for the additional OD runs to demonstrate problem-free grape juice concentration using this equipment with corrected and reliable temperature control function. The demonstrated excellent water removal results indicate that this program was successful and the commercialization effort should be continued with additional funding. PARTICIPANTS: Not relevant to this project. TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The results from this Phase II program were: a thinner non-porous perfluoromembrane material is available for osmotic distillation (OD); the new in-line, in-house coating process does not plug the pores to the extent that in-situ batch coating does; the thinner coating uses less of the expensive perfluoromembrane material (presently over $10,000/lb) and leads to more favorable process economics; we produced increased the stability of the membrane to potential wet-out by covering over any "unprotected" pores in the porous hollow fiber substrate; reduced fiber bridging which can cause wasted perfluoro membrane material, dead spaces in the flow through the OD module, and later cleaning and sterilization problems; eveloped the in-line coating process comprises of a hollow fiber passing through a pulleys from a feed spool at a fixed tension and speed, immersed in a polymeric solution capable of forming a membrane coating on the hollow fiber substrate, passed a deionizing blower, and rolled on to a take-up spool; optimized variables for in-line coating: solvent, polymer solution concentration and viscosity, fiber winding speed, fiber porosity, drying time, and drying temperature; optimized polypropylene (PP) and polyvinylidene fluoride (PVDF) hollow fiber coating procedures; the Henis-Tripodi method can be used for defect repair but has definite limitations; defect repair may best be done at the fiber level (fibers passed through a bath of polydimethylsiloxane) before winding; gas separation is a good tool for evaluation of defects and correlating defects to location along fiber; most defects were identified as mechanical/handling defects; the OD equipment constructed for this program was successfully used to demonstrate grape juice concentration; the OD water removal from grape juice was more than adequate to demonstrate the usefulness of the OD process; the cost of using OD to concentrate the grape juice has been calculated to be $2.89 - $3.30 per gallon of concentrate, depending on the scale of the OD process.
Publications
- No publications reported this period
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Progress 10/01/04 to 09/30/05
Outputs
Our efforts in membrane module fabrication during Phase II of this grant are focused on developing an in-line coating process for polypropylene (PP) and/or polyvinylidene fluoride (PVDF) hollow fibers (HFs). We have installed a HF coating system and multiple head winder at our facility (funded from outside this program). The key design variables for investigation include: solvent, polymer concentration, polymer viscosity, fiber winding speed, fiber porosity, drying time, and drying temperature. Over the coming months, we will study the effects of these variables on coating success. CMS coated HFs are only usable for OD once fabricated into a module. We have designed and manufactured a housing with a translucent shell that allows for visible inspection of flow path and assessment of fluid mixing, fluid channeling, and dead spots. It is entirely comprised of plastic to avoid corrosion from the brine. For testing purposes, the end caps of the housing are removable to
identify leaks or broken fibers. We will manufacture a full-size module utilizing this housing design. Due to unforeseen circumstances, equipment and personnel needed to make membrane modules for this grant are being used to manufacture a customer product that was previously manufactured outside of CMS. We are thus experiencing a delay in module supply for this grant, which affects downstream tasks as well. We expect to be producing membrane modules for this grant during the second quarter of 2006. A major initiative in this program is to increase the processing rate of OD. From work to date, we believe that the best microporous support for the OD process will combine hydrophobicity and an asymmetric structure. To that end, we are pursuing the use of PVDF as our microporous support. Preliminary coating work on this fiber has been encouraging. Foresight conducted their TNA for this grant and raised concerns about low OD flux and high concentrate cost. Dr. Zoecklein of VATech (our
subcontractor and an expert in the wine industry) and CMS agree that the biggest barriers to entry into the market are quality and cost. The low flux of the requires that more membrane area be used to achieve a desired production rate, which does directly affect the cost of the process. However, a concentrate of high quality would provide value above what is currently available and would therefore command a higher price than the cost-driven, high-volume concentrates currently available. We plan to move ahead with demonstrating the sensory quality of the concentrates, then getting samples into the field for testing to better determine the value of the concentrate. Dr. Zoecklein is very well connected in the field, particularly in the cooler growing regions where we are most likely to find acceptance and value, and is available to help with getting us the right contacts and exposure when the time comes. The grape juice needed to perform the initial taste testing has been prepared and
frozen for us by Dr. Zoeckleins group at Virginia Tech.
Impacts
The successful development of non-wetting osmotic distillation membranes should provide a valuable unit operation for developing high concentrations of various fruit juices and other heat sensitive beverage with minimal loss in quality. The net effect of successfully completing this program will be the development of a family of high value agricultural based beverages including concentrating of fruit juice but also other non-conventional beverages such as coffee and tea. The net result will be significant value added products to the broad agricultural food and beverage products.
Publications
- No publications reported this period
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