Chemical facilities use a variety of hazardous gases and solvents in their production processes. Danger is present when hazardous buildup of flammable vapors in the atmosphere gets rich enough to ignite or explode. The National Fire Protection Association (NFPA) establishes fire safety standards, including standards for safe operation of processes.
NFPA 86, the Standard for Ovens and Furnaces, addresses the safe operation of ovens, dryers, furnaces and fume incinerators. These codes establish that the safety ventilation rate shall be designed to prevent the vapor concentration from exceeding 25% LFL. This rate is based on the oven’s maximum solvent load.
If the process typically runs below its maximum load, then excess ventilation air is being run through the oven. This excess ventilation results in higher operating costs. HOWEVER, if a continuous solvent vapor concentration indicator and controller is installed to continuously monitor the oven, the vapor concentration is allowed to rise as high as 50% LFL.
This real-time measurement allows the implementation of several money-saving steps:
- A reduction of ventilation air without affecting existing production rates
- An increase in production speed without increasing existing air or fuel cost
- Compound savings by reusing, rather than expelling, some of the hot exhaust stream back into an oven zone
- Reduction of oven exhaust rates to lower the demand on VOC destruction oxidizers
- Reduction in fuel costs by burning richer samples
Benefits can range from a simple reduction of heated ventilation air to a combination of reduced heating, increased burner efficiency and increased production. This can result in dramatic fuel savings as well as protection of your investment.