Realizing the Benefits of Ceramic Fiber Insulation

November 2005

Ceramic fiber insulation has been used in industrial furnaces for more than 30 years.  Chief among its benefits, when compared to insulating firebrick, are reduced furnace operating expense due to lower energy storage, rapid cooling capability, and faster heating and recovery rates.  Halliburton learned that prefabricated fiber panels could also be used to make rapid, effective, and long-lasting furnace repairs.  But fiber insulation systems are not without problems, as Rolls Royce, Howmet, and Airex discovered.  Fortunately, they also found a way to fully realize the benefits of ceramic fiber while eliminating the drawbacks.

Challenges

Rolls Royce Engine Services repairs jet engines, and they use furnaces to heat-treat various engine components.  "One of our furnaces was shutting itself down repeatedly.  The old fiber lining had deteriorated to the point where it was actually breaking heating elements during operation, which would abort firing cycles," reported Alex Kagan, an Engine Services Engineer for Rolls Royce.  Increased maintenance expense and interrupted productivity were the results. 

Howmet Georgetown Casting specializes in making intricate aluminum and copper-based castings for the aerospace industry.  Howmet had previously replaced the fiber lining of one of its furnaces in-house using a competitive fiber product, "but the result was not as durable as we had hoped, and the heat losses were higher than we wanted," explained Bob Hesselink, Howmet's Maintenance Supervisor.   The foundry industry can be tough on furnace insulation.  Ceramic fiber has to withstand the process, and the occasional abrasion and impact that can occur during loading and unloading operations, while preserving a tight heat-seal.    

The issue of heat leakage was of great concern to Airex as well.  Airex is a manufacturer of premium quality regenerative thermal oxidizers that include a ceramic fiber-lined combustion chamber.  Operations Manager Richard Whitford described the challenge.  "Ceramic fiber insulation is a very important aspect of our thermal oxidizer design.  If ceramic fiber is not installed properly, hot spots occur that can burn through the steel shell and cause serious problems," he said.

Halliburton had an emergency.  The company manufactures diamond tool bits used in the oil drilling industry.  When the roof of one of their production furnaces unexpectedly collapsed, Halliburton needed a solution right away - one that would last for many years.  "The loss of production for one day in a single furnace can cost the company $100,000 or more," explained Kelly Malone of their Manufacturing Engineering department. 

All four companies turned to Keith for help.

Expertise

Keith Company has designed and built special ceramic fiber-lined furnaces for more than 30 years.  In 2002, Keith acquired KMI Refractories, and adapted its fiber module fabrication technology to meet the highest quality standards in the industry.  Wim Sijen, Keith's Engineering Manager, has been a key participant in these developments for nearly 20 years.  "We've learned how to choose the best fiber materials, how to consistently assemble large modules that have uniform size and density, and how to install those modules to minimize shrinkage and eliminate hot spots," he explained.  "We focus on the little details that make such a big difference in the field.  Long experience has proven that this approach works best."

Solutions

When Rolls Royce contacted Keith and explained their furnace troubles, Keith proposed a completely new modular insulation system, with new heating elements, and field installation services.  "When we first talked to Keith, we liked their technical approach, their willingness to help, and their fast response.  The job would have taken us 2 or 3 days to complete, but when Keith showed up, it got done in a single day," said Operations Manager Jose Rojas.  "Keith did a fantastic job of replacing the insulation and heating system in our old furnace, which had become a maintenance nightmare.  Since then, it has not given us a single problem, and that was several years ago," he added.

Howmet's story was a little different.  They wanted all the benefits of a superior ceramic fiber lining, but didn't want to fly a Keith serviceman several thousand miles for a single day's work.  So Keith designed and built modular insulation panels that Howmet personnel could install.  "Before making the new panels, Keith made sure they got the design right.  The panels they shipped fit perfectly the first time, and were extremely easy to work with.  They were more rugged than our previous fiber lining, were easy to install, and they've resolved our heat loss problem.  Plus, the new panels fully complied with our internal health and safety requirements.  That's why we will continue to use Keith insulation panels whenever we rebuild our furnaces," Bob Hesselink explained. 

In the thermal oxidizer business, Airex had lots of experience with ceramic fiber materials and installation techniques.  "We've paid close attention to all the details, so our systems have a longer life expectancy than our competitors because of the ceramic materials, installation, and anchoring methods we use," said Richard Whitford.  But refractory installation services were subcontracted, and different vendors required varying degrees of supervision, adding to the complexity of manufacturing.  Occasional hot spots in the field requiring warranty repair were the expensive result.  "We've had many companies install ceramic fiber for us in the past, but since Keith started doing most of our work about 3 years ago, hot spots have been virtually eliminated," he stated. 

Halliburton found a long-term solution that quickly got their furnace back in production.  Kelly Malone explained, "Keith quickly fabricated a new fiber roof, and shipped it to us by air.  We installed the new roof in about three hours, and it fit like a glove.  We were back in business just a few days after calling Keith.  Their customer service was excellent," he added.  Halliburton has successfully used Keith fiber insulation systems for many years.

Conclusion

The economic, durability, and performance benefits of ceramic fiber insulation can be fully realized in many furnace applications, as these few examples demonstrate.  When custom insulation systems are properly designed, the right materials are chosen, the insulation panels are expertly fabricated, and the correct installation procedures are followed, the results will meet and often exceed expectations.  And long-lasting fiber panels can be quickly fabricated to minimize furnace downtime in critical applications nationwide. 

Keith has demonstrated these capabilities in many different industries, in a wide variety of situations, using either Keith's installation services, or competent local labor following Keith's installation procedures.

"Keith really knows what they are doing, and they've done a great job for us," summed up Whitford of Airex.