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Chemical and Process Engineering Resources

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Category: Plant Economics
Question: How are refineries controlling the refinery accounting loss in order to identify actual physical loss?
Keywords: refinery,refineries,accounting,loss,actual,physical,loss,losses
Answer: Mr. David Morris of Standard Heater Tube Inc:You are correct to distinguish between refinery accounting losses, which are abstractions, and actual physical losses, which are real and true. Many times, accounting losses are due to inaccurate flow meters, incorrect temperature measurement data, and the like. It is not a question of having a loss, but of having a proper accounting. It is a question of how good the numbers are. Actual losses, on the other hand, represent real dollars lost. Most refining losses are due to evaporation in some form, although chemical change, what is called stochiometry, can account for some volume change (usually the volume change will INCREASE, as with cracking operations, or hydrocracking, but for some processes, such as polymerization or alkylation plants, there will be a net decrease). Any net decrease in volume from feedstock to product must go into the "loss" category by default. These losses can sometimes be identified by taking a careful MATERIAL BALANCE, where it is the weight of all products together that is considered and compared to the weight of all feedstock materials, rather than volumes (which can either contract or expand with no corresponding weight change). The approach for true physical losses is to first identify the part of the plant the problem revolves around, then concentrate on that part of the plant, breaking the problem down into more and more narrow areas until it is located. I found one huge loss where product was leaking into the water side of an exchanger, then going as an emulsion to the cooling tower, where the fans made the product evaporate. For 20 years everyone thought it was only an accounting loss, since it couldn't be located. We checked and rechecked all meters, tank readings, checked and rechecked the product density factors, without success. There was one bleeder valve which had never been opened. When it was opened, it revealed "oil in the water" on the way to the cooling tower. My best advice to you is to make the accountants do their job, which is to ACCOUNT for losses, and concentrate your own efforts on finding and eliminating any REAL PHYSICAL losses, which hurt not only profits, but the world we live in. Don't accept complaints which blur these two different entities, no matter how loudly they are made. They are not the same thing.