The search for sustainable solutions in the heat treat industry is at the forefront of research for industry experts. Michael Stowe, PE, senior energy engineer at Advanced Energy, one such expert, offers some fuel for thought on the subject of how heat treaters should prioritize the reduction of their carbon emissions by following the principles of reuse, refuel, and redesign.
This Sustainability Insights article was first published in Heat Treat Today’s January/February 2024 Air & Atmosphere print edition.
Reduce
PE, Senior Energy Engineer
Advanced Energy
We explored why the question above has come to the forefront for industrial organizations in Part 1, released in Heat Treat Today’s December 2023 print edition. Now, let’s look at the four approaches to managing carbon in order of priority.
The best way to manage your carbon footprint is to manage your energy consumption. Therefore, the first and best step for reducing your carbon footprint is to reduce the amount of energy you are consuming. Energy management tools like energy treasure hunts, energy assessments, implementation of energy improvement projects, the DOE 50001 Ready energy management tool, or gaining third party certification in ISO 50001 can all lead to significant reduction in energy consumption year over year. Lower energy use means a smaller carbon footprint.
Additionally, ensuring proper maintenance of combustion systems will also contribute to improved operational efficiency and energy savings. Tuning burners, changing filters, monitoring stack exhaust, controlling excess oxygen in combustion air, lubricating fans and motors, and other maintenance items can help to ensure that you are operating your combustion-based heat treating processes as efficiently as possible.
Reuse
Much of the heat of the combustion processes for heat treating goes right up the stack and heats up the surrounding neighborhood. Take just a minute and take the temperature of your exhaust stack gases. Chances are this will be around 1200–1500°F. Based on this, is there any effective way to reuse this wasted heat for other processes in your facility? One of the best things to do with waste heat is to preheat the combustion air feeding the heat treating process. Depending on your site processes, there are many possibilities for reusing waste heat, including:
- Space heating
- Part preheating
- Hot water heating
- Boiler feed water preheating
- Combustion air preheating
Refuel
Once you have squeezed all you can from reducing your process energy consumption and reusing waste heat, you may now want to consider the possibility of switching the fuel source for the heat treating process. If you currently have a combustion process for a heat treat oven or furnace, is it practical or even possible to convert to electricity as the heating energy source? Electricity is NOT carbon free because the local utility must generate the electricity, but it typically does have lower carbon emissions than your existing direct combustion processes on site. Switching heating energy sources is a complex process, and you must ensure that you maintain your process parameters and product quality. Typically, some testing will be required to ensure the new electrical process will maintain the metallurgical properties and the quality standards that your customer’s specific cations demand. Also, you will need a capital investment in new equipment to make this switch. Still, this method does have significant potential for reducing carbon emissions, and you should consider this where applicable and appropriate.
Redesign
Finally, when the time is right, you can consider starting with a blank sheet of paper and completely redesigning your heat treating system to be carbon neutral. This, of course, will mean a significant process change and capital investment. This would be applicable if you are adding a brand-new process line or setting up a new manufacturing plant at a greenfield site.
In summary, heat treating requires significant energy, much of which is fueled with carbon-based fossil fuels and associated-support electrical consumption. Both combustion and electricity consumption contribute to an organization’s carbon footprint. One of the best ways to help manage your carbon footprint is to consider and manage your energy consumption.
For more information:
Connect with IHEA Sustainability & Decarbonization Initiatives www.ihea.org/page/Sustainability
Article provided by IHEA Sustainability
