Research Grants/Fellowships/SBIR

Final Report: Retrofit Air Pollution Control Filter for Restaurant Underfired Charbroilers

EPA Contract Number: EPD09026
Title: Retrofit Air Pollution Control Filter for Restaurant Underfired Charbroilers
Investigators: Wright, Steve R.
Small Business: Innova Tech, Inc.
EPA Contact: Manager, SBIR Program
Phase: I
Project Period: February 1, 2009 through July 31, 2009
Project Amount: $70,000
RFA: Small Business Innovation Research (SBIR) - Phase I (2009) RFA Text |  Recipients Lists
Research Category: SBIR - Air Pollution , Small Business Innovation Research (SBIR)


Purpose:  The purpose of the project was to demonstrate the technological feasibility of a new medialess self-cleaning inertial aerosol filter as a potential retrofit replacement for ineffective grease filters above underfired charbroilers used in restaurants. The large underfired charbroiler installed base of approximately 321,000 units in about 700,000 food service operations/restaurants in the U.S. contributes 94 percent of current daily restaurant emissions, equivalent to > 285 tons of particulate matter (PM) and > 41 tons of volatile organic compounds (VOCs) each day, a significant source of environmental air pollution that can adversely impact health. Current conventional emissions control technologies include:  catalytic conversion, electrostatic precipitators (ESPs), traditional media filtration, centrifugal separators or cyclones, wet scrubbers, absorbers/adsorbers, after-burners, odor masking, and other types of process change. They are either:  (a) too capital intensive to install, (b) too costly to operate/maintain, or (c) have inefficient overall filtration performance, allowing significantly more emissions than the current 5 mg/m3 emissions standard. As aerosol grease emissions from one underfired charbroiler are estimated to be 2.15 MT/year, national technology implementation of a device achieving nominally 70 percent reduction in grease emissions has potential pollution reduction capabilities of 483,105 MT/year, which would significantly reduce smog in major urban areas. Therefore, a retrofit implementation approach to new emissions control technology for fine particle (PM2.5) air quality compliance is required for these charbroilers. 
Progress and Accomplishments:  A new cost-effective emissions control system, two-thirds less energy intensive than conventional alternatives, that integrates (a) a novel self-cleaning inertial disk filter (already commercialized as a metalworking oil mist eliminator) with (b) a proprietary water mist evaporative cooler for VOC condensation and (c) a continuous grease removal system for long-term unattended operation was developed. Two different sized prototypes were examined in the Phase I effort:  (1) a full-scale 500-CFM rotary disk filter to compare particulate removal efficiencies at room temperature with competitive technologies already in the marketplace and (2) a smaller scale 1000-LPM (= 35.3 CFM) rotary disk filter combined with H2O mist injection to demonstrate high temperature grease vapor removal. Integrated spray nozzles within the prototype, periodically spraying a commercial degreaser, allow for continuous operation without significant grease build-up. Technology attributes/benefits include:  compactness, ease of maintenance/service, enhanced removal efficiencies (both particulate and vapor), increased environmental compliance, enhanced worker/customer safety, reduced capital and operational costs, elimination of contaminated media disposal in landfills, and long service life.

Summary/Accomplishments (Outputs/Outcomes):

Results:  All project technical objectives were achieved. These include:  (1) demonstrating a high-efficiency 500-CFM prototype, (2) demonstrating prefilter grease vapor condensation, (3) showing PM collection/clean-in-place with no significant buildup of grease over time, (4) determining nominal prototype operating parameters, (5) achieving > 70 percent reduction in PM grease emissions, and (6) comparing/contrasting prototype filtration performance/economics with conventional technologies. The 500-CFM rotary disk filter demonstrated mass removal efficiencies > 99 percent for oleic acid aerosol particles > 1 µm at particle concentrations < 40 mg/m3, significantly better performance than all of the “high-end” technologies currently in the market. Grease vapor filtration performance of the prototype was demonstrated using active cooling/vapor condensation via injection of nebulized water mist during high-temperature filtration performance testing using the smaller scale 1000-LPM rotary disk filter prototype. This unit also demonstrated > 98 percent removal of aerosol particulates at particle concentrations < 40 mg/m3. Moreover, a simulated charbroiler operating at > 500oF generated nominal upstream grease vapor (VOC) concentrations of 605 + 18 ppm measured using a flame ionization detector (FID). Without evaporative cooling, these downstream measurements were the same as the upstream measurements (i.e., no grease vapor reduction). With evaporative cooling, however, measurements of the nominal downstream grease vapor concentrations were reduced to 352 + 12 ppm, corresponding to a nearly 42 percent VOC reduction. 


NovaMistTM aerosol particulate filtration test data clearly demonstrate superior filtration performance when compared to the best commercial grease filters on the market. Other competitive grease filters do not even address the capture of grease vapor, another contributing factor to environmental degradation generated from underfired charbroilers. The combination of high efficiency particulate filtration and the successful demonstration of grease vapor reduction are key performance attributes of the NovaMistTM grease filtration system that will differentiate it from other competitors in the marketplace. Positive project results provide technological proof-of-concept to restauranteurs and environmental professionals that device retrofit and subsequent commercialization will have significant upside potential with reduced risks. 
The basic hypothesis that was proven in Phase I efforts was that water mist injected upstream of the NovaMistTM aerosol grease filter prototype caused evaporative cooling and concomitant grease vapor condensation, resulting in the least amount of grease contaminants (both particulate and vapor) transferred to the environment. 
Value Proposition:  InnovaTech will be able to offer a quality, extremely high performance retrofit aerosol grease filtration system with integrated clean-in-place capabilities for continuous operation by the end of Phase II activities, an improvement over inefficient already-fielded conventional systems offering enhanced environmental air quality emission compliance at a high perceived value/premium price.
Potential Applications of the Research:  Potential U.S. commercial device sales for underfired charbroiler restaurant grease emission control is > $2B. The technology also can be adapted to improve emissions compliance of industrial process gas streams including streams from agriculture (pesticides), power generation, transportation, construction/mining, petrochemicals, etc. Economies will be gained in long-term sustainable process efficiencies, reduced operation/maintenance/disposal costs, decreased filter cleaning/replacement down time, enhanced worker (OSHA/NIOSH) safety, environmental friendliness, and greater compliance with EPA PM2.5 emission requirements.
Because of InnovaTech’s unique product differentiation and intellectual property (IP) protection, NovaMistTM technology could become an industry standard. Marketing/consumer education can be used to set a "high bar" for competitive performance. Competitive products would have to demonstrate (with independent verification/validation) that their grease filters are as good as or better than the NovaMistTM—very time consuming and hard to do—targeting customers/end users that desire a high quality product with top end performance specifications.
The feasibility research in Phase I demonstrated much better particle filtration efficiency than conventional grease filters in the market, as well as grease vapor reduction, a current performance weakness in competitors' market approach that can be exploited with InnovaTech’s technology. InnovaTech participated in the EPA-sponsored Commercialization Program (CAP) with Foresight Science & Technology. Industry experts on commercial kitchen ventilation/grease filtration testing and potential commercialization partners identified by Foresight in their Technology Niche Analysis (TNA) report to InnovaTech were contacted. Some of these industry experts can provide independent 3rd party testing/validation of the NovaMistTM aerosol grease filtration system in subsequent Phase II efforts at their test facilities. InnovaTech has a successful commercialization track record using a licensing strategy (i.e., seeking strategic partners to license marketing, sales and distribution rights to its technology)Five of the top corporations from the list of potential commercialization partners (currently competitors) identified in the TNA report (CaptiveAire, Captrate, Greenheck, Halton, and Gaylord Industries) will be provided summaries of the Phase I test results to stimulate additional interest in commercializing the NovaMistTM aerosol grease filtration system upon successful completion of Phase II follow-on activities. As a contingency, up to 35 alternative kitchen ventilation hood manufacturers also may be contacted in Phase II, depending on the success of early negotiations with any one of the five major market players identified above.

Supplemental Keywords:

small business, SBIR, EPA, particulate matter, PM, volatile organic compounds, VOCs, air pollution, underfired charbroiler, restaurant emissions, emissions control, PM2.5, air quality, cost-effective, filter, water mist, evaporative cooler, grease removal, aerosol particles, aerosol grease emissions, proof-of-concept, smog, environmental compliance, contaminated media disposal, compact, industrial process gas streams, pesticides, power generation, transportation, construction, mining, petrochemicals, worker safety, reduced costs

Progress and Final Reports:
Original Abstract

SBIR Phase II:

Retrofit Air Pollution Control Filter for Restaurant Underfired Charbroilers  | Final Report