KILN CONNECTION: Persistence Pays Off
A relatively new employee of one of my regular clients called me in late 2005. He had just been put in charge of an older tunnel kiln (TK) firing building brick, and he was interested in yield improvement and energy efficiency. This TK had been retrofitted with a pulse firing system a few years previously, and the fuel consumption, while not bad, was hurting the plant's profitability. I guess that's a typical story these days, as natural gas has risen from $3 per MCF to $7-12. While pricing has eased somewhat, futures for January 2007 are around $11/MCF, plus transport charges. It is impossible to absorb that kind of increase in energy cost and still remain profitable.
I visited this employee-we'll call him Dilbert-at the beginning of 2006 for a couple of days. During that visit, we simply reviewed operating principles and pulse firing systems. As with many kilns in the brick industry, this TK incorporated some unusual systems (particularly in the cooling zone), and we spent most of our time trying to figure out what they were used for. I didn't make any adjustments, but we did discover that some systems were only semi-functional; other systems weren't working at all. In short, we just did the normal things that I always do when considering energy:
- develop an O2 survey
- develop a pressure survey
- develop a burner setting survey
- evaluate the exchange of air from heating to cooling
- evaluate the functioning of the pulse firing system
With these bits of data in place, we developed a program for energy reduction.
ResultsWhen I work this way under normal circumstances, my customers' fuel savings usually range from a few percent to perhaps 10%. We accomplish this by having an e-mail dialog that usually lasts a few months. Then the plant's day-to-day activities tend to take over, and the program sort of stops. Energy conservation takes continual effort and analysis, and in many plants there is just not enough time. In fact, many plants pay their kiln people $15/hour to monitor kilns that cost millions of dollars and consume millions more in energy every year-but that's another column!
Dilbert sent me Datapaq curves and we discussed the fine points of burner adjustment, air flow management, etc. He found some burners that had damaged internal parts, and he left no stone unturned in his dogged pursuit of improvement. He also evaluated energy use in each zone of the kiln, looking for better stability and energy savings. The results that he produced, in only six months, were astounding:
- Fuel savings exceeding $1000/day, or $360,000 per year. (Boy, I'd like to have his bonus for such excellent work!)
- Increased output of 12.5%. (Note that the total fuel used in this kiln decreased while the output increased.)
- Significant improvement of kiln yield due to improved firing stability and accuracy.
After six months of hard work, Dilbert's contribution to this plant's profitability probably approaches a million dollars a year. Do you have a Dilbert in your plant? Maybe you should get one!