What’s Next in Boiler Technology

Oil & Energy Magazine reached out to Dr. Thomas Butcher, Director of NORA Laboratory, for updates on his research into renewable fuels and what we can expect as boilers become more efficient and adapt to these new fuels.

O&E: You gave a presentation “NORA Technical Projects Update” at the Eastern Energy Expo. Could you provide an overview of some of the research you are working on and how it might relate boilers and boiler technology?

Dr. Butcher: Research at NORA is focused on two main topics – efficiency and biofuels. At the Eastern Energy Expo (EEE) we presented work on the technical aspects of the transition to biofuels. Overall, our focus is on ensuring that the industry has the option to make this transition without technical issues. We have been very involved with field testing high blends of biodiesel, to B100, over the past few years and in-lab studies of the long-term performance of burners with B100. Most of this has been focused on boilers. Different boiler types can handle B100 differently. Generally, with higher-temperature, refractory-lined chambers we find longer-term performance to be somewhat better. Another important factor is cycling patterns. Short cycling does not allow the chamber temperatures to reach their steady state values and can contribute to carbon deposits on burner heads. Changing boiler control settings can greatly help reduce short cycling.

O&E: There was also a presentation on your Field Study with Chevron on B100 and R100 performance at more than 130 live sites. First of all – how did the 100 percent renewable fuels perform!

Dr. Butcher: We are very enthusiastic about the field study. It involves testing of two blends of Renewable Diesel (RD) and Biodiesel (B). One is RD50/B50 and the other is RD80/B20. We have a total of 133 homes participating in this study, split between Pennsylvania and Massachusetts. We are testing the full range of equipment types: 76 percent of the sites are boilers, 21 percent are furnaces and 3 percent are water heaters. This test started recently, with the test fuel blends being delivered “on-top” of the fuel already in the tank. For this reason, we have mostly been in a period of transition to these fuels. We made a deliberate decision not to empty or clean the tanks prior to the delivery of the test fuels because we feel this is the most realistic deployment situation. At the present time, many of our test sites are still in a transition period but there have been no field problems to date. This test will run for a full year and we will be making detailed visits to many of the sites and tracking service requirements for all sites.

The field sites include 20 different appliance manufacturers and we wanted to have units that reflect the most common types in use and also the wide range of system types. Nine different fuel marketers are participating in the project and this project would not be possible without their support and enthusiasm.

In addition to the field tests, we have been doing tests in boilers at the NORA lab with these blends to understand, before the field work started, what to expect in terms of combustion performance. This testing work has not indicated any likely performance concerns either with the combustion of the blends or with transitions from the pre-existing fuels to these test blends.

O&E: Second – were there differences in performance based on boilers? What changes in equipment structure are you now recommending?

Dr. Butcher: It is really too early to make any recommendations about changes in equipment. We will be making site visits and providing updates as the work progresses. At the end of the project we will prepare and release a detailed technical report of all results and also shorter summary reports with lessons learned and recommendations.

O&E: I know you have seen Roger Marran’s “From Blue Flame to Biofuels” history of boiler technologies, also in this issue. He ends with a look at where technology may be going. But can you expand on what is new in boiler technology for this year, what you see coming in the near future, as well as long term?

Dr. Butcher: As noted in Roger’s article, the industry has been working to increase steady state boiler efficiency and AFUE and the long term pressure in this direction is expected to continue. However, we feel there is also significant potential to increase the actual operating efficiency in the field through reducing boiler jacket and off-cycle losses. Many of our boiler systems provide both heat and domestic hot water and spend a great deal of time at low load conditions. As part of the NORA Rebate Program, we have done studies of actual reductions achieved with boiler system upgrades. We find these actual savings far exceed what would be expected based on AFUE alone and improving the low load performance is a critical part of this.

O&E: Based on your research, are there any changes you recommend to “traditional” maintenance and repair procedures to optimize the use of renewable fuels?

Dr. Butcher: As we transition to renewable fuels, I feel it is very important to keep up with regular maintenance including annual service to ensure combustion performance is correct and burner components are clean and in accordance with manufacturer recommendations.

With renewable fuels, as with traditional fuels, good filtration and keeping water out of fuel tanks are critical to avoiding service issues.

We have also found that fuel additives can make a significant difference in equipment operations for all fuels. When using higher blends of renewable fuels, the right additive can offer advantages including improved stability and reduced pour point.

O&E: Is there anything else you’d like to add?

Dr. Butcher: The transition to renewable fuels is an exciting time for the industry. As we go through this, it is important that the fuels we use be of good quality, meeting, at least, the ASTM specifications. In a few, rare, cases we have seen lower quality “biofuels” become available on the market. As with any fuel, ensuring good quality of supply and good handling and maintenance practices is an important part of minimizing service issues.

Our thanks to Dr. Butcher for his time and consideration. If you have any questions about fuel quality, higher blends of renewable fuels, and heating equipment technology, you can contact Dr. Thomas Butcher at tbutcher@noraweb.org.

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