Optimizing Furnace Efficiency with Six Sigma

Economic impact of over $184,000!

Since the 2001 Plant Expansion the throughput of Furnace #4 has been less than the design Operating Equipment Efficiency of 295,140,698 pounds of propane feed.  In 2004 the furnace operated 304 of 344 operating days at 69.8% of design.

Total throughput for the 2004 calendar year was 205,952,599 pounds of propane processed.  The average since 2001 has been consistent with this performance.  The goal of this project was to increase the throughput of #4 furnace by 62,431,669 pounds.

Based on given plant dynamics this additional throughput will have a substantial impact on plant operating economics.

The focus of corrective actions, using our Six Sigma training, targeted the Process Control System programming used to manipulate the furnace temperature and other problems limiting the stability of furnace operation.

• The programming logic was broken down into segments and analyzed for issues impacting the overall consistency of the furnace environment.
• Lean techniques were applied to various operational and maintenance issues resolving many problems associated with Gas Chromatography feedback (Used to control furnace conversions).
• The most significant change resulted from surveillance of the regression calculation used in the feed forward control method of the fuel gas valve set point.
• New programming for balancing of flows between coils created a more stabile unit.
• Lean Six Sigma techniques were applied to increase our hours of operation in supervisory control of #4 furnace.

Throughput has been increased by more than 49,000,000 pounds annually.  This will have economic impact of over $184,000.