Grantee Research Project Results

Final Report: Controlling Cooking Effluents With a Self-Cleaning Adsorbent

EPA Contract Number: EPD08027
Title: Controlling Cooking Effluents With a Self-Cleaning Adsorbent
Investigators: Benedict, Laksham
Small Business: EERGC
EPA Contact: Richards, April
Phase: I
Project Period: March 1, 2008 through August 31, 2008
Project Amount: $69,999
RFA: Small Business Innovation Research (SBIR) - Phase I (2008) RFA Text |  Recipients Lists
Research Category: Small Business Innovation Research (SBIR) , SBIR - Air and Climate

Description:

In many urban areas the emissions of fine particulate matter (PM_2.5) and volatile organic compounds (VOC) from commercial cooking operations significantly contribute to the failure to achieve air pollution goals. Under-fired charbroilers emit the greatest quantity, followed by chain-driven charbroilers. Cost-effective emissions control technology currently exists for only the latter, lesser emitter.

EERGC Corporation is developing a self-cleaning adsorbent that would economically capture PM_2.5 and VOC for all types of cooking operations and periodically regenerate itself by oxidizing the adsorbed material.

The Phase I effort consisted of preparation of the adsorbent materials, building an experimental setup to test the adsorbents, testing the adsorbents under both the capture and cleaning modes, and providing a preliminary design and cost estimate for a replacement filter for use in a commercial kitchen.

Summary/Accomplishments (Outputs/Outcomes):

As summarized in Figure 1, laboratory experiments have been conducted with beds of two adsorption substrates (designated “coarse” or “fine”) with and without a self-regenerating oxidation catalyst (designated “substrate” or “catalyst”). Smoke, generated by dripping olive oil onto a hot plate, was drawn through the beds (in “adsorption” mode), then the beds were heated (in “cleaning” mode) to the point where the captured smoke would be either driven off or oxidized by the catalyst. A smoke alarm, situated in the exhaust stream very close to the blower exit, was used to assess the effectiveness of the bed at adsorbing the smoke and the catalyst at oxidizing it. In initial tests, the smoke alarm was open to the atmosphere (designated “open”); and in later tests the smoke alarm was partially shielded (designated “closed”) to prevent inconsistent results due to random wind currents. The figure presents the results of the smoke alarm data in terms of alarm trip frequency (i.e., the reciprocal of the time that it takes to trip the smoke alarm). An alarm trip frequency of zero means that the alarm never went off (the desirable outcome indicating that the smoke was successfully adsorbed and/or oxidized), and a high alarm trip frequency means that the alarm went off very quickly (indicating that the bed was not completely adsorbing and/or oxidizing the smoke).

Figure 1. Summary of Smoke Alarm Data.

The experimental results have shown that:

• The smoke alarm was sensitive enough to detect smoke at the rates/concentrations we were generating as evidenced by the baseline (no bed) tests, which consistently tripped the alarm with smoke from a single drop of oil.
• The higher surface area (“fine”) substrate was a better smoke adsorbent than the lower surface area (“coarse”) substrate.
• For the better (higher surface area) adsorbent, the mixed bed (including both catalyst-impregnated and blank substrate) adsorbed smoke as well as the blank substrate.
• When the catalyst bed with adsorbed smoke was heated, oxidation occurred. The temperature rose faster in the bed containing catalyst-impregnated adsorbent than in the bed containing only the adsorbent substrate.
• When the bed with catalyst-impregnated high surface area adsorbent and adsorbed smoke was cleaned by heating/catalytic combustion, complete combustion occurred and virtually no smoke was emitted as evidenced by the fact that the smoke alarm never tripped.

Preliminary design/cost estimates for application to restaurant charbroilers suggest that the self-cleaning adsorbent will be significantly less expensive than the current state-of-the-art (a catalytic oxidizer) for under-fire charbroiler applications; and will be cost competitive with catalytic oxidizers for chain-driven charbroiler applications.

Conclusions:

This project has experimentally demonstrated the feasibility of the concept (i.e., that an adsorbent bed with a self-regenerating combustion catalyst is capable of capturing smoke and evaporated oils in cooking effluents, and cleaning itself without generating more effluents in the process). Moreover, it has shown that the proposed technology is significantly more cost effective than the current state-of-the-art for controlling effluents from under-fired charbroilers, which currently emit more VOC and PM_2.5 than other commercial restaurant cooking applications.

Supplemental Keywords:

small business, SBIR, EPA, air quality, control of air pollution, commercial kitchens, particulate matter, PM_2.5, volatile organic compounds, VOCs, secondary organic aerosols, SOAs, urban, emissions, organic materials, cooking effluents, catalytic oxidation, adsorbent, pollutants/toxics, sustainable industry/business, scientific discipline, RFA, technology for sustainable environment, sustainable environment, chemicals, environmental chemistry, adsorption processes, cooking emissions, particulate emissions, emission controls, restaurant, kitchen,, Sustainable Industry/Business, RFA, Scientific Discipline, POLLUTANTS/TOXICS, Technology for Sustainable Environment, Sustainable Environment, Environmental Chemistry, Chemicals, particulate emissions, adsorption processes, emission reduction, emission controls, cooking emissions