JL Clark, headquartered in Rockford, Illinois, is no ordinary packager. The company, which celebrated its 115 year anniversary in 2019, is recognized around the world for its award winning metal lithography and exact graphic reproduction.
Also recognized as a long-time positive corporate influence in the community, the management of the company was naturally concerned about the need to comply with US EPA regulations specific to air quality, specifically Volatile Organic Compound (VOC) and Hazardous Air Pollutant (HAP, or air toxics) control. With legislation looming on the horizon, in early 2003 the company began a thorough review of the pending EPA requirements and a corresponding search for a company that could provide a system that would exceed the minimum requirements and do so as cost-effectively as possible.
This was not the first time that JL Clark had taken steps to control their emissions. Years earlier, the company had installed several recuperative thermal oxidizer (RTO) systems that had satisfied earlier requirements but had, over the years, become outdated and was a significant drain on the plant’s operations budget. Costs to operate the systems had become a major component of Clark’s annual fuel usage.
After an exhaustive search and thorough review of various proposals, JL Clark selected Anguil to partner with them to meet their emission requirements and at the same time reduce their operational costs. After a kick-off meeting, all parameters were established and agreed upon and work was begun.
The Anguil solution included a 50,000 SCFM (80,250 Nm3/hr) Regenerative Thermal Oxidizer (RTO) to control the emissions and a Permanent Total Enclosure (PTE) to capture the emissions from the plant’s six presses. The selection of the RTO technology was important because it guaranteed the requirement of at least 98% destruction of the VOCs but also because it was seen as an effective way to reduce overall plant operation costs because of its inherent lower operating costs compared with the current VOC control devices.
HOW THE REGENERATIVE THERMAL OXIDIZER WORKS
The Anguil Regenerative Thermal Oxidizer (RTO) destroys air toxics and VOCs that are discharged in industrial process exhausts. The Anguil system achieves VOC destruction through the process of high temperature thermal oxidation, converting the VOCs to carbon dioxide and water vapor, recycling released energy to reduce operating costs.
Process gas with VOC contaminants enters the two chamber RTO through an inlet manifold. A flow control valve directs this gas into an energy recovery chamber which preheats the process stream. The process gas and contaminants are progressively heated in the stoneware bed as they move toward the combustion chamber.
The VOCs are then oxidized, releasing energy in the second stoneware bed, thereby reducing any auxiliary fuel requirement. The stoneware bed is heated and the gas is cooled so that the outlet gas temperature is only slightly higher than the inlet temperature. The flow control valve switches and alternates the stoneware beds so each is in inlet and outlet mode. If the process gas contains enough VOCs, the energy released from their combustion allows self-sustained operation. For example, at 95% thermal energy recovery, the outlet temperature may be only 77° F (25° C) higher than the inlet process gas temperature. PLC-based electronics automatically control all aspects of the RTO operation from start-up to shutdown so that minimal operator interface is required.
THE IMPORTANCE OF THE PERMANENT TOTAL ENCLOSURE
PTEs contribute significantly to the reduction in VOCs released to atmosphere. VOC reduction by a pollution control device only can affect the VOCs delivered to this device. There can still be significant fugitive emissions from the processes which need to be accounted for. For example, older processes with capture efficiencies of 70-85% can result in sufficient emissions that can cause the facility to reach a facility emission cap even with pollution control equipment installed. The installation of a PTE can allow the facility to capture 100% of those process emissions if certain criteria are reached with the PTE design and installation. This high capture rate, along with high VOC destruction rates of new or modified equipment, will significantly decrease the overall emissions from a facility. This reduction can allow for additional expansion of production equipment emitting VOCs without reaching the facility emission limit. The PTE installation can effectively allow for additional production capacity.
In 1990, the EPA issued a capture efficiency guideline which would allow the user the legal presumption of 100% capture efficiency of VOCs without the requirement for formal capture testing. Specifically, the following description applies:
If a source is located inside a “total enclosure” and all emissions are directed to a control device, the requirement to measure the efficiency of capture is waived and presumed 100%. By definition then, a “total enclosure” precludes fugitive emissions. Such an enclosure can be described as a structure that completely surrounds or enshrouds an affected facility such that all VOC emissions are contained and directed through an exhaust stack or into an oven.
On November 13, 2003 the US EPA issued a final rule promulgating national emission standards for hazardous air pollutants (NESHAP) for metal can surface coating operations located at major sources of hazardous air pollutants (HAP). These standards (5700 liters/1,500 gallons of coatings per year) dictate that plants affected by this derivative of the Clean Air Act must meet HAP emissions standards reflecting the application of the Maximum Achievable Control Technology (MACT). The standards outline various control requirements based on usage of affected compounds but also provide for emission reduction via a capture system in conjunction with the pollution control device.
JL Clark’s forward thinking and alliance with Anguil produced a capture system and pollution control device that not only meets the since-enacted EPA requirements but exceeds them. The PTE has proven effective at capturing the emissions from the wet-end coating operations of the process lines-that exhaust is combined with the exhaust from the ovens at the inlet of the RTO. This results in 100% capture efficiency of the VOC/HAP emissions assuring capture efficiency requirements and eventual destruction. The high-efficiency RTO itself has proven to be similarly effective, achieving destruction efficiency in excess of 99% while exceeding all fuel usage reduction objectives! The combined capture and destruction efficiency has therefore exceeded 99% for the facility, minimizing the overall VOC/HAP emissions from the facility and allowing the facility to meet their emissions cap.
The result is a partnership that further enhances JL Clark’s reputation as an industry and community leader and provides Anguil with yet another satisfied customer, one of almost 1,500 around the world.