Grantee Research Project Results

The purpose of the project was to demonstrate technological feasibility of a new medialess self-cleaning inertial aerosol filter as a potential retrofit replacement for ineffective grease filters used in restaurants above underfired charbroilers. The large underfired charbroiler installed base of approximately 321,000 units in about 700,000 food service operations/restaurants in the U.S. contribute 94% 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 or other types of processes. These are (a) too capital intensive to install, (b) too costly to operate/maintain, or (c) have inefficient overall filtration performance, allowing significantly more than the current 5 mg/m³ emissions standard. Since aerosol grease emissions from one underfired charbroiler is estimated to be 2.15 MT/yr, national technology implementation of a device achieving nominally 70% reduction in grease emissions has potential pollution reduction capabilities of 483,105 MT/yr, significantly reducing smog in major urban areas. Therefore, a retrofit implementation approach to new emissions control technology for fine particle (PM-2.5) air quality compliance is required for these charbroilers.

Results: All project technical objectives were achieved: (1) a high-efficiency 550-CFM prototype was demonstrated, (2) prefilter grease vapor condensation was demonstrated, (3) PM collection/CIP was demonstrated with no significant buildup of grease over time, (4) nominal prototype operating parameters was developed, (5) > 70% reduction of PM/vapor grease emissions was achieved, and (6) prototype filtration performance/economics was favorably compared/contrasted with conventional technologies. The aerosol grease filter demonstrated mass removal efficiencies > 99% for oleic acid aerosol particles > 1 µm at particle concentrations in the 10-to-40 mg/m³ range, higher performance than comparable technologies currently in the market. Moreover, efficient prototype grease vapor filtration was also successfully demonstrated using active cooling/vapor condensation via injection of nebulized water mist during high-temperature filtration performance testing. A simulated underfired charbroiler operating at > 450^oF generated nominal upstream grease vapor (VOC) concentrations of 580 + 20 ppm measured using a flame ionization detector (FID) and photo ionization detector (PID). Without upstream evaporative cooling, there was negligible grease vapor reduction; i.e., the downstream VOC measurements were comparable to the upstream measurements. However, with evaporative cooling, nominal downstream grease vapor concentration measurements were reduced to 350 + 15 ppm, corresponding to ~ 40% VOC reduction. Since total grease filtration efficiency consists of both particulate and vapor, typically in a 60:40 ratio respectively, then one of the major project goals of > 70% reduction in total grease emissions was achieved.

NovaMist^TM aerosol particulate filtration test data clearly demonstrates superior filtration performance than that of competitive commercial grease filters in the marketplace. Water mist injected upstream of the NovaMist^TM aerosol grease filter prototype generated > 25^oF evaporative cooling temperatures with concomitant grease vapor condensation, resulting in the lower amounts of both particulate and vapor grease contaminants transferred to the environment. Other competitive grease filters only report grease PM reduction. They do not even address the capture of grease vapor, which is a major constituent of total grease emissions that contributes to environmental degradation from unregulated underfired charbroilers. High efficiency grease particulate filtration in combination with successful grease vapor reduction are key performance attributes of the NovaMist^TM grease filtration system that differentiate this technology from those of other competitors in the marketplace. Positive project results provide technological proof-of- concept to restaurateurs and environmental professionals that device retrofit and subsequent commercialization has significant upside potential with reduced risks.

 

Value proposition: InnovaTech can offer enhanced environmental air quality emission compliance with high perceived value within an efficient high-quality/high-performance retrofit aerosol grease particulate/ vapor filtration system with integrated clean-in-place capabilities for continuous unattended operation, a significant improvement over other conventional grease aerosol filtration systems.

 

Potential Applications of the Research: Potential U.S. commercial device sales for underfired charbroiler restaurant grease emission control is > $2B. The technology can also be adapted to improve emission compliance of industrial process gas streams: 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 (OSHA/NIOSH) worker safety, environmental friendliness and greater compliance with EPA PM-2.5 emission requirements.