Users view of variable speed drives on petrochemical plant

The author describes how Exxon Chemical at its Fawley complex recognised the potential value of variable speed on process plant in the 1970´s when a prototype variable speed drive (VSD) was tested on the MEK plant. This failed due to poor reliability. In early 1988, they were convinced that power convertors had become sufficiently reliable to try again. 18 VSD´s were installed on a new process unit. Since then all motors in new projects have been considered for VS operation with a positive end result for 50%. Also, a number of retrofits have been implemented. These applications are to the `bread and butter´ pumps, fans and compressors which are the basis of chemical plant operation