Posts Tagged ‘Air Pollution Control Device’

VOC Test Methods & Modifications Part 1: What is the Purpose of the VOC Emissions Test?

Choosing the most appropriate test method(s) and method modification(s) for accurate Volatile Organic Compound (VOC) emissions measurement can be confusing. To establish the best VOC testing method or combination of VOC testing methods, first determine the purpose of the VOC test.

A.  Compliance

1. Determine Air Pollution Control Device (APCD) efficiency. Emissions from a faulty APCD can often be difficult to quantify, but if left unaccounted for, they can have a critical impact on source compliance and statewide emission inventories.
2. Identify emissions entering the atmosphere – VOC as VOC and organic hazardous air pollutants (HAP)

B.  Engineering

1. Discover VOC emission profile versus process operations and/or PCD
2. Ensure compliance under differing operational scenarios

C.  Survey

1. Source has never been tested or received unreliable test data
2. Unknown emission composition and compounds
3. Tests are necessary to measure total VOC and organic HAP

See Air Compliance Testing’s next post for a set of helpful questions to determine the most accurate VOC test methods and modifications for your facility.

Air Compliance Testing can help develop a Site Specific Test Plan for your EPA compliance testing requirements. We can help determine the best EPA test methods to maximize the accuracy of VOC and HAP emissions measurements. Our experts can identify the most appropriate EPA test methods to determine the specific process emission variables (e.g., temperature, moisture content, VOC concentration, grain loading, particle size distribution, etc.) necessary for the design and specification of air pollution control (APC) equipment. Contact us today for more information about our Test Protocol Consulting Services for your facility.

Air Pollution Control Devices for VOC Emissions

The typical Air Pollution Control Devices (APCD) and methods used to control Volatile Organic Compounds (VOC) Emissions are:

Carbon Adsorption – Carbon adsorption is often used to control emissions from organic compounds because it’s possible to recover the valuable organics found in the emission stream. In carbon adsorption, the concentration of a substance remains entirely on the surface. The substance does not dissolve or penetrate through a liquid or solid.

Condensation – Like adsorption, this method is used to recover valuable organic compounds. A decrease in temperature and/or increase in pressure causes the VOCs in the emission stream to condense. The clean air is removed from the condensate air stream containing VOC pollutants.

Incineration – Catalytic oxidizers, thermal oxidizers and flares all use oxidation to control VOC emissions. With high temperatures and adequate residence times, combustion can oxidize almost all hydrocarbons to carbon dioxide and water.

Floating Roof Storage Tanks – Floating roofs in storage tank systems reduce VOC emissions that are caused by evaporation by decreasing the evaporative loss of liquids and vapors during storage. There are three types of these systems: External Floating Roof Tanks, Internal Floating Roof Tanks and Domed External Floating Roof Tanks.

Often, VOC emission sources processes are not enclosed or contained. Therefore, before VOC emissions can be routed to an APCD, they first must be captured by a capture system. Most capture systems are unable to secure 100% of the emissions. The capture efficiency (CE) of a system does affect a VOC emissions estimate, so it’s important to understand the capture system’s effectiveness before conducting an emissions test.

Air Compliance Testing offers a variety of Test Protocol Consulting Services for EPA compliance. We can help you develop a site specific test plan and help create an engineering testing strategy to identify and troubleshoot any energy saving opportunities or specific process concerns. Air Compliance Testing can aid in the design of an appropriate permanent (PTE) or temporary total enclosures (TTE) if your permit mandates capture efficiency determination. Contact Air Compliance Testing to learn more about our EPA Testing Consulting Services.

Monitoring Air Pollution Control Device Performance

Air Pollution Control Devices (APCD’s) are pieces of equipment designed to capture or destroy pollutants which would otherwise be released to the atmosphere. The emission reduction efficiency of an APCD is expressed as the Control Efficiency (CE). CE calculates the amount of emissions controlled by an APCD, process change, or reformulation. The following calculation is primarily used to determine control efficiency:

Uncontrolled Emission Rate – Controlled Emission Rate
_____________________________________________ X 100
Uncontrolled Emission Rate

Factors that may influence control efficiencies of APCDs include:

Age:  The control efficiencies of APCDs can deteriorate over time if not regularly maintained. Efficiency may decline due to warping, corrosion, and the accumulation of surface dust that cannot be removed.

Maintenance:  Proper maintenance is required to maintain control efficiency. Without routine maintenance, efficiency will decline.

Operating Conditions:  Operating conditions must be frequently monitored to ensure the APCD is operating under the right conditions for maximum efficiency. Pay attention to pressure levels, temperatures, etc. Also, be sure the throughput to the APCD is relative to its capacity.

A malfunctioning APCD can greatly increase the annual emissions of a source, even if the miscalculations account for only a small percentage of the operating time. Excess emissions also influence statewide emission inventories that are solely based on emission levels specified in regulations or permits. Emissions from a faulty APCD can often be difficult to quantify, but if left unaccounted for, they may actually have a more critical impact on source compliance than previously believed or reported.

APCDs are stable and usually operate in the same manner for all processes. Most stack tests are mandated to be conducted at 95 percent to 100 percent of a facility’s permitted capacity. Prior to air compliance testing, it’s recommended to observe the APCD for any abnormalities that may occur, especially if the source is not accustomed to operating at almost full capacity.

Air Compliance Testing offers a variety of Test Protocol Consulting Services to assist with your facility’s EPA air permit compliance testing requirements. We can help you select the most appropriate EPA test methods, assist in the design of permanent total enclosures (PTE) or temporary total enclosures (TTE) if your permit requires capture efficiency determination and identify the best EPA test methods to determine the emission variables necessary for the design of your air pollution control devices. Also, we can negotiate with the EPA to achieve a reasonable and cost-friendly test protocol. Contact us today to learn more about our Compliance Test Protocol Consulting Services.