Better Furnace Insulation
Reducing furnace exterior temperatures by installing better insulation can cut heat losses, which saves fuel year-round and reduces worker discomfort in summer. Under some operating conditions (e.g., oxygen-deficient atmosphere), however, dropping the exterior wall temperature below a critical point can cause hydrocarbons to diffuse and deposit into porous insulating materials and create subsequent problems such as fire or environmental contamination. Alternatively, if acid gases are present in the furnace, these may diffuse through insulating materials and condense on a cold wall, causing corrosion and deterioration of the furnace shell.
High-temperature thermal storage is becoming more commonplace, and molten salt is proving to be a popular storage medium. For metallurgical operations with molten-salt quench baths, a solar concentrating system can be employed to heat and melt the salt, which can then be stored overnight in a well-insulated vessel. However, solar mirrors are not hazard-free devices. Mirrors that focus sunlight can cause skin or eye injuries if they malfunction when workers are in vulnerable locations.
Replacement of traditional fossil fuels with biofuels or waste-to-energy fuel blends may save money and reduce carbon emissions, but burners and other combustion-system components likely need replacement or redesign to safely burn non-traditional fuels. Secondary consequences (e.g., plugging, fouling) related to ash or slag accumulation may also result from the combustion of bio-solids. Storage and handling of combustible solids may lead to unintended accumulations of combustible dust and the explosion hazards associated therewith.
The bottom line: When implementing a new energy-saving idea, seek assistance from a trusted member of technical staff or outside specialist if the changes could affect process safety. Perform appropriate safety reviews and obtain engineering change approvals if system functionality will be altered in any significant way.
This blog is my last as a regular contributor to Industrial Heating magazine. I have been writing about safety and environmental issues since January 2008, and it has been a pleasure to have researched and opined on a wide variety of interesting and practical topics. I want to express my gratitude to IH for providing me the opportunity to do something I love – write about thermal technologies. And to IH readers, I send a strong wish for your workplaces to be enriched with excellence as you practice safety for your colleagues and care for the environment.