Research Project Summary Information
Crucible Furnace Demonstration(ST9916-1)
Beacon Glass Works, Inc.
Beacon Glass Works, Inc. (The Contractor) is located in Beacon, New York. Beacon produces glass tiles and glass artwork. Beacon makes small lot products of different colors. It is not unusual to change the product color every day or so. Products are low cost tiles and higher cost art pieces. Beacon produces 100,000 pounds of glass per year, of which 74,000 pounds are sold. The balance is discarded due to quality flaws. Beacon currently has one tank furnace that processes 500 pounds per day using mixed batch and cullet. The batch is formulated by Beacon. The furnace is gas-fired,with sealed burners, and ratio control for the air/fuel mixture. Operation is manual and the furnace firing rate is determined by the flame’s appearance and the glass product. There is no furnace pressure control. The furnace idles when not melting. Idling likely results in substantial energy use as the furnace idles over the weekend, during product pull, and when melting is completed during shifts two and three. The furnace is rebuilt about every two years, which takes about two weeks.
Beacon proposes to replace its glass tank with a crucible furnace. A crucible furnace consists of a ceramic crucible sitting inside a refractory box furnace. Burners fire through the box furnace heating and melting the batch in the crucible. The crucible furnace will be provided by The Hub Consolidated, Inc. (Orwell, VT). The melt never comes in contact with the furnace walls but is contained in the crucible.
The crucible furnace will be installed at Beacon. The furnace will be operated and produce product for sale. During its operation, the following will be measured:
1. Batch going into the furnace
2. Rejected glass that is recycled back into the furnace
3. Rejected glass that is land filled
4. Energy use
5. During rebuilds, the amount of refractory land filled will be weighed.
The above will be compared to the existing furnace, including an economic evaluation, to determine the crucible furnace’s performance. In addition, an optical pyrometer will be used to measure the glass melt temperature. This will allow better control of product quality.
The benefits to Beacon can be summarized as follows:
o Low thermal inertia, so less energy use. The furnace can be idled at a lower temperature since it takes less time to reach its operating temperature.
o Heat recovery is provided. The combustion air can be preheated to 300 to 400F, resulting in additional energy savings.
o Less product loss since the glass comes in contact only with the crucible. Refractory wear does not affect glass quality as with a tank furnace.
o Easier to turn around products. It is easier to clean out old product from the crucible while setting up a new product line.
o Crucibles will last about four months and cost approximately $1,000 to replace. The spent crucibles are not land filled; they are sold as upscale planters.
o The furnace comes with automated controls. Furnace pressure control will also be installed.
In addition, the technology results will be disseminated to other New York companies similar to Beacon, which may result in significant replication.
The original project installed an advanced Crucible Furnace at Beacon Glass, to reduce energy use and improve glass quality compared to their conventional tanks furnace. The energy use was reduced by 32.3%. Unfortunately, the crucibles themselves were damaged from the molten glass and never exceeded 29 melts before being replaced. Since 40 melts is needed for economical operation, the Crucible Furnace was temporarily decommissioned in 2009. However, in 2010, after meeting with industry experts, Beacon used a different glass formulation and a lower feedstock temperature combined with a smaller diameter crucible and achieved a crucible longevity of 123 melts, greatly exceeding the minimum of 40 required for economical performance. The Crucible Furnace’s energy savings for 2011 was measured at 36.6% compared to the tank furnace. An annualized savings of 460 MMBtu and $5,623 resulted. In addition, product scrap was reduced, resulting in an annualized savings of $6,720 for a total annual cost savings of $12.343.
Beacon Glass Works, Inc.
71 Maple St
Beacon, NY 12508
On-site Process Improvement
NYSERDA Contact Information
R&D - Mfg Tech & On-Site Pwr