Compared to other emission control technologies, Regenerative Thermal Oxidizers (RTO) are particularly reliable and carry a low operating cost. The increased energy efficiency is gained from the recovery and ultimate recycling of the surplus heat energy created by the process of combusting the organic materials in the air stream. This high energy efficiency comes in at around 95% and even, in some circumstances, 97%.
Developed for large volumes and low VOC concentration air pollution applications, Regenerative Thermal Oxidizer technology is based on using ceramic media as heat exchangers and for switching valve(s). (This design is in contrast to Recuperative Thermal Oxidizers which use metallic shell and tube heat exchanger technology with primary and secondary heat exchangers. In this configuration, among other distinctions, the outgoing clean process stream of the secondary heat exchanger process is routed to another part of the plant for its use or back to the process itself.)
A Regenerative Thermal Oxidizer (RTO) System is based upon the principle of thermal oxidation, which utilizes the process of regeneration for internal heat recovery.
The RTO Process Overview
The RTO unit is brought up to combustion temperature using supplemental fuel such as natural gas, propane, diesel, or bio-fuel. During this start up period, the RTO unit initially purges itself with fresh air and continues to process fresh air until it reaches combustion temperature equilibrium. The RTO unit is then ready to switch over to process air and begin the thermal oxidation of VOC with destruction efficiencies over 99%.
The RTO switches from start-up mode running on clean air to operating on VOC process air from the source. To maximize heat recovery, the RTO will automatically cycle or alternate the inlet and outlet via a series of pneumatic, electric, or hydraulic valve(s).
Overall, because an RTO is so efficient at reclaiming effluent heat, the units oftentimes are capable of sustaining combustion temperatures without any supplemental fuel, utilizing the VOC as its only source of fuel.
Disadvantages to Consider
Multiple factors are taken into consideration when incorporating pollution control devices into a manufacturing plant’s processes and infrastructure.
Depending on these and even the end product itself, in some operations, the following potential disadvantages of a Regenerative Thermal Oxidizer may outweigh the advantages.
These drawbacks include: high electrical costs, the installation’s need for a larger real estate footprint, as well as a weight spec that can be up to three times that of a recuperative oxidizer.
Regardless, the distinct advantages presented by a regenerative oxidizer, are clear:
* Design simplicity
* Minimal metal expansion issues
* High thermal efficiency
* Extremely low operating costs
Regenerative Thermal Oxidizers are designed to be highly energy-efficient systems, particularly for long continuous operations. Additionally, they even achieve high levels of VOC destruction to keep processes well below required DRE emission levels.