Any business that relies on combustion equipment in its production processes has an obvious imperative to ensure that ovens and furnaces are operating as efficiently as possible. This is true whether the process is baking, drying, curing, smelting, melting, heat treating or cogeneration, and regardless of the industry — food, die casting, glass, steel, automotive, mining, chemical or petrochemical. Significant savings and risk reduction can be achieved by improving the performance of the combustion equipment being used. A company that uses ovens or furnaces in its industrial processes cannot be a best-of-class company if it does not have best-of-class efficiency in those systems.
Oven and furnace retrofits typically result in annual energy reductions of at least 30 percent. That may sound high, but it is a conservative estimate, and many energy reductions are higher. These savings can be achieved because when combustion equipment ages, it usually is far from as efficient as it should be — and many companies have not improved their systems in decades. Company leaders and engineers who were around when these furnaces were installed are often long gone, and the furnaces and ovens have essentially been operated as is. Maybe they have received some minor tweaking to improve them, but more than likely, most of the attention they receive is costly, frequent maintenance just to keep them running.
In addition to the performance benefits, retrofitting also can enhance safety. Aging furnaces and ovens often are not compliant with current safety codes, and they are more prone to fail in a manner that can produce dangerous results.
Businesses are always looking for ways to minimize risk, lower costs and increase throughput in their industrial operations. An opportunity to realize all those benefits may very well lie in your combustion equipment.
Benchmarking: How Are Your Company's Thermal Processes Performing?
Before you can consider the merits of investing in combustion improvements, you will want to know how your efficiency compares to what is possible. An illuminative exercise is to determine your total energy cost per unit of output (e.g., by weight units) and then to benchmark that cost against the best in class.
The table provides some sample approximate benchmarks developed based on data from Siemens VA Metal Technologies, Boston Consulting Group and Natural Resources Canada. The “IISI EcoTech Plant” benchmark is a hypothetical plant used in a study by the Canadian Steel Industry Program for Energy Conservation, which conceived it as an example of a plant that makes efficient use of commercially available energy-saving technologies.
Because of the varied ways in which industrial combustion processes are used — as well as the many industries in which they are essential — it is important to determine the appropriate benchmark numbers for your process and industry. You can turn to your internal operational expertise or to outside specialists in combustion processes to help determine the right benchmarks and gauge the current situation.
Even before benchmarking, it is possible to get a reasonable idea of the need for retrofitting by asking some basic questions about the condition of the oven or furnace. The following are common indicators that improvements could lead to substantial energy savings:
- The plant is older than 20 years old.
- The annual (inflation-adjusted) energy budget keeps rising each year.
- Energy budget overruns are common.
- The company has been fined or visited by a compliance body.
- The team does many manual activities (e.g., cleaning up dross, cycling the burners) to keep production rolling.
- The oven or furnace is not tightly sealed, allowing unnecessary heat loss and ingress of cold outside air.
The Benefits of Best-in-Class Thermal Processing
If your company is not at a best-in-class level in combustion equipment efficiency, why is an investment to reach that level a smart business decision? The business case rests on the following:
- Greater Productivity. Increased efficiency almost always results in greater throughput for less cost.
- Improved Quality. Furnace and oven retrofits often enable companies to improve product quality.
- Minimized Downtime. Modernized equipment avoids the excessive downtime that comes with the continual failures and repairs of old furnaces that have had no improvements in many years.
- Enhanced Safety. Combustion inefficiency often goes hand-in-hand with safety issues when equipment does not receive the ongoing upgrades that are needed.
- Compliance with Emissions Standards.With environmental regulations tightening everywhere, the reduced emissions that come with increased combustion efficiency keep you on the right side of regulations.
- Avoidance or Delay of Large Capital Projects. Renovating a furnace or oven means it does not have to be completely replaced.
Best Practices for Industrial Oven Retrofit Projects
If your company’s efficiency is not best-in-class, retrofitting will almost always provide significant risk minimization and a robust return on investment. The following steps are recommended best practices for all companies.
Assess the State of the Furnace or Oven. This is where benchmarking is important. This is also a time to get the input of the people managing and working with the systems being retrofit as well as to start monitoring energy usage. This information allows you to begin setting goals.
Consider the Entire Combustion Process to get the Best Results. Simply replacing worn-out or old items is not enough to gain the full benefits of a retrofit. Putting a new part into a bad system is not the answer. The entire furnace or oven will need to be evaluated holistically to determine the best solutions for maximizing efficiency.
Make a Business Case to Get Approval for the Project. Retrofit projects often meet internal resistance due to issues such as company politics, attachment to the “way we have always done things” and competing budget agendas. To help gain approval for the project, create a formal business case that clearly shows the costs savings versus the capital cost.
Approach the Project in Stages. Retrofit projects are no different than new capital projects, and they benefit from a structured project delivery model. The retrofit should be divided into stages (e.g., assessment, concept selection, basic engineering, detailed engineering, procurement, construction, commissioning), and each stage should be complete before moving to the next.
Test and Measure. Furnace efficiency should not only be tested during commissioning, it should be continually tracked so that process adjustments can be made if the system is not operating at peak efficiency.