Grantee Research Project Results
Final Report: UV-LED Photocatalytic Fuel Vapor Emissions Control
EPA Grant Number: SV840016Title: UV-LED Photocatalytic Fuel Vapor Emissions Control
Investigators: Almquist, Catherine
Institution: Miami University
EPA Project Officer: Aja, Hayley
Phase: II
Project Period: July 1, 2020 through June 30, 2022 (Extended to September 30, 2023)
Project Amount: $74,663
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet - Phase 2 (2020) Recipients Lists
Research Category: P3 Awards
Objective:
Our ultimate goal was to develop a cost-effective and technologically feasible UV LED photocatalytic device that could be incorporated into an automobile to reduce evaporative fuel vapor emissions by at least 70% compared to current fuel vapor emission control systems. Three design parameters on which Phase 2 efforts were focused are: 1) the size and construction of a light weight, low power cylindrical prototype, 2) the durability of the photocatalytic film, and 3) the power, intensity, and distribution of the UV LEDs. An automobile manufacturing representative suggested that the prototype be lightweight, low power, low cost, and highly effective for inclusion into the existing on-board refueling vapor recovery (ORVR) systems.
The Phase II objectives and strategies were to: 1) Construct a cylindrical UV LED photocatalytic fuel vapor emissions control device that is 3 cm diameter by 10 cm in length, a size that can fit into the current ORVR system; 2) Demonstrate a photocatalytic film that is durable to abrasion and vibrations and when exposed to water vapor; 3) Identify and assess the limitations of this technology for the following experimental variables: the intensity and wavelength of the UV LEDs at the photocatalytic film, the illuminated area and type of photocatalytic film, residence time, concentration and type of hydrocarbon, humidity, and the longevity of service life of our device; 4) Demonstrate the operation of the prototype in standard test systems; 5) Conduct an economic analysis for the proposed technology to assess economic attractiveness from multiple perspectives (auto manufacturers, human health, regulations); and 6) Design and develop educational and marketing tools for this technology.
Summary/Accomplishments (Outputs/Outcomes):
Each of the objectives were met in our Phase 2 efforts. A summary of the outcomes achieved in this study is provided below.
The US EPA Tier 3 regulations for evaporative fuel vapor emissions are designed to eliminate fuel vapor evaporative emissions. Considering all types of evaporative fuel vapor emissions from a light-duty automobile, the Tier 3 standards require less than 0.300 g/test over a 2-day and 3-day evaporative emission test. The Tier 3 standard for just the diurnal evaporative fuel vapor emissions from the fuel tank and carbon canister of a light-duty vehicle is <0.02 g/test. Constraints on size, weight, cost, and power were placed on our prototype device from the automobile manufacturing industry. At the advice of the automobile parts manufacturer, the device was relatively small and lightweight, and the power required was low (~6 W). Given these constraints, the results of our prototype UV LED photocatalytic device did not meet the Tier 3 standard diurnal evaporative fuel vapor emissions test, as approximately 30 mg or 0.03 g of fuel vapors were emitted when our prototype device was in operation during a standard evaporative fuel vapor emissions test.
A challenging dilemma to overcome with gas-phase photocatalysis is catalyst deactivation. While our prototype device was able to effectively oxidize ethanol vapor (< 200 ppm) for over 30 days with very little deactivation, the high concentrations of fuel vapors in the headspace of a fuel tank and the presence of aromatic hydrocarbons lead to rapid photocatalyst deactivation. Methods to regenerate the photocatalyst and modifications to the photocatalyst to prevent deactivation must be further developed to open up more new and innovative applications of gas-phase photocatalysis.
The power to the device was also considered. A typical car battery is rated at approximately 50 amp-hours (Ah), and it can provide the required 12 V for the UV LEDs in our device. The UV LED photocatalytic device uses approximately 0.5 A (12 V, 6 W), and so the standard car battery could power the UV LED device for ~100 h (or approximately 4 days) before the battery would need to be re-charged.
If the challenges are overcome, the UV LED photocatalytic device is reasonably economical as a final evaporative fuel vapor emission control element. The materials for our prototype cost approximately USD 35. This cost is reasonable, considering that vehicle technology changes to meet Tier 3 evaporative fuel vapor emissions is projected to cost USD 130 per vehicle.
Aspects regarding the use of a UV LED photocatalytic device for diurnal evaporative fuel vapor emissions control in an automobile that must be considered include: 1) the longevity of the photocatalyst, 2) the regeneration of the deactivated catalyst, and 3) ease of maintenance and installation of the device. In addition, all safety aspects and controls for the device must be considered when incorporated into an automobile. The operational controls must also be considered to determine when the device should be powered on and off.
Educationally, the project had a significant impact on the students who worked on the project. Overall, including both Phase 1 and Phase 2, 22 undergraduate students and 1 MS student worked on the project from 2018-2023. Many of these students sought employment in STEM fields in the private sector, while others pursued higher education.
Journal Articles:
No journal articles submitted with this report: View all 10 publications for this projectSupplemental Keywords:
UV LED, photocatalysis, fuel vaporsRelevant Websites:
US EPA P3: UV LED Photocatalytic Evaporative Fuel Vapor Emission Reduction Device YouTube Video Exit
Progress and Final Reports:
Original AbstractP3 Phase I:
UV-LED Photocatalytic Fuel Vapor Emissions Control | Final ReportThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.
Project Research Results
- 2023 Progress Report
- 2022 Progress Report
- 2021 Progress Report
- Original Abstract
- P3 Phase I | Final Report
3 journal articles for this project