MARCH'S PUZZLER

摘要

We use a variety of solvents at our pharmaceutical plant.Until recently,we largely ignored the vent system feeding our thermal oxidizer(TOX).Although the decanting and distillation tower for separating solvents works flawlessly,the TOX system sometimes acts up;the environmental regulators forced us to install a backup system.Lately,the vent system drew our attention when vapor detectors caused a trip during new solvent unloading.Then,everything went haywire.I was sent by corporate to investigate.The operator claims the suction is very bad and truck drivers complain about the fumes.I found out that,to avoid the fumes,the drivers hook up and walk away and the operator watches from the control station.Plant engineering gripes that a series of expansion projects connected to the system without addressing underlying problems.With budget cuts,corporate says there isn't any money.One engineer grumbles that the vent alarm is faulty;he says the over-loaded distributed control system suffers from a power supply problem that causes alarm trips.