Grantee Research Project Results

Final Report: Membranes for Air Venting and Retaining VOCs in Gasoline Storage Tanks

EPA Contract Number: 68D02014
Title: Membranes for Air Venting and Retaining VOCs in Gasoline Storage Tanks
Investigators: Nemser, Stuart
Small Business: Compact Membrane Systems Inc.
EPA Contact: Richards, April
Phase: I
Project Period: April 1, 2002 through September 1, 2002
Project Amount: $70,000
RFA: Small Business Innovation Research (SBIR) - Phase I (2002) RFA Text |  Recipients Lists
Research Category: SBIR - Pollution Prevention , Pollution Prevention/Sustainable Development , Small Business Innovation Research (SBIR)

Description:

As part of this Phase I research project, Compact Membrane Systems, Inc. (CMS), developed a technology to reduce volatile organic compound (VOC) emissions from underground gasoline storage tanks. Existing CMS membranes demonstrate good separation capability-they reduced VOC emissions from an underground storage tank from 30-60 percent to 3-6 percent. The goal of this project was to reduce these emissions further, to the VOC level of 1 percent, consistent with U.S. Environmental Protection Agency (EPA) regulations. The focus of this study was the introduction of various additives to the CMS membrane to directly modify the separation capability, or in a hybrid manner, oxidize the small portion of hydrocarbons that subsequently permeate through the membrane.

Summary/Accomplishments (Outputs/Outcomes):

The findings are summarized as follows:

· Additives could be introduced into the membrane structure with a volatile precursor and subsequently expose the membrane to a reactant. The net result would be to convert the volatile precursor to a nonvolatile form.

· The effect of molecular-level additives on performance was modest. There was no significant change in the effect of plasticization, and no significant change in the selectivity.

· A hybrid process that included a photocatalytic agent on the downstream side of the membrane surface was developed. The concept was that the membrane would provide an inherent level of separation, and subsequently, the small residual hydrocarbon permeating would be photocatalytically oxidized.
· A commercial photocatalyst was introduced in the membrane. The membrane reduced VOC concentration by 90 percent when various VOCs (e.g., butane, heptane, propylene) were exposed to the photocatalyst surface and an appropriate light source.

Conclusions:

The product concept from this Phase I research project is the introduction of photocatalyst sites on the downstream surface of the membrane. These photocatalytic sites will oxidize a large portion of the VOCs that go through the membrane. Combining photocatalytic oxidation with membrane permeation, VOC emissions can be reduced by 95-98 percent. This clearly meets and exceeds project goals as well as the goals established by EPA.

Supplemental Keywords:

membranes, air pollution, emissions, volatile organic compound, VOC, gasoline storage tanks, hydrocarbons, plasticization, butane, heptane, propylene, SBIR, Sustainable Industry/Business, RFA, Air, Scientific Discipline, Toxics, Technology for Sustainable Environment, Chemical Engineering, Civil Engineering, Sustainable Environment, Environmental Chemistry, Engineering, Chemistry, & Physics, VOCs, cleaner production/pollution prevention, air toxics, Environmental Engineering, treatment, gasoline storage tanks, reverse membrane system, VOC removal, VOC recovery, abatement, gaseous effluent streams, underground storage tanks, membrane technology , Volatile Organic Compounds (VOCs), VOC emission controls, fugitive emissions

SBIR Phase II:

Membranes for Air Venting and Retaining VOCs in Gasoline Storage Tanks  | Final Report