Optimization of a wood dryer kiln using the mixed integer programming technique: A case study

When wood is to be utilized as a raw material for furniture, buildings etc. , it must be dried from approximately 100% to 6% moisture content. This is achieved at least partly in a drying kiln. Heat for this purpose is provide d by electrical means, or by steam from boilers fired with wood chips or oi l. By making a close examination of monitored values from an actual drying kiln it has been possible to optimize the use of steam and electricity usin g the so called mixed integer programming technique. Owing to the operating schedule for the drying kiln it has been necessary to divide the drying pr ocess in very short time intervals i.e., a number of minutes. Since a dryin g cycle takes about two or three weeks, a considerable mathematical problem is presented and this has to be solved.