Consider the following:
- At any hour of the day there are likely to be more than 10,000 oxidizer systems in service, using a high temperature reaction chamber (with or without catalyst) to treat the exhaust gases from a wide range of industrial processes.
- The final component of nearly all of these oxidizer systems is an exhaust stack, where the treated exhaust gases are released to the atmosphere at elevated temperatures.
- Historically, oxidizer systems have been sized to treat exhaust airflows from 100 SCFM (Standard Cubic Feet per Minute) up to several hundred thousand SCFM. But conservatively, the average oxidizer system airflow processing capability (i.e. “size”) can be estimated to be between 15,000 and 20,000 SCFM.
- Now, considering these 10,000 stacks emitting hot, treated gases to the atmosphere around the clock; if heat recovery equipment capable of dropping the exhaust stack temperature by 100 ˚F could be installed into each one of them, this would lead to an overall value of over 18 billion BTUs (British Thermal Unit) per hour of energy conservation!
- In dollars - assuming $10/MM BTU and year round operation – this equates to recovering over $1.5 billion worth of energy per year!
Taking this into account, it is no surprise that a wide range of stack energy recovery options have been developed and marketed to end-users of oxidizer systems. This article will discuss three important aspects of energy reclamation from hot oxidizer stacks:
1. Energy reclamation from oxidizer stacks is one of three potential areas of optimization for oxidizer systems.
2. There are distinct challenges that must be addressed in the process of evaluating potential energy savings options.
3. There are multiple potential equipment options for this application, each with its own benefits and limitations.