For stable production of follow-up processes, such as in atmospheric or vacuum furnaces and for yield increase of light oil, the bottom level of the crude oil distillation unit and the furnace outlet temperature are vital. The production process demands a temperature difference of no more than 2 C between the header tubes and branch tubes and a failure to control outlet temperature is very likely to result in partial burning and the coking of furnace tubes. In similar fashion, a drastic fluctuation in the bottom level is likely to result in substandard products, or a shutdown of the equipment. So, Huaxing Petrochemical has increased its automated instrument use in the 6-million-ton crude oil distillation unit, from 60 to 90 percent, an improvement that ensures smooth operation, reduces labor intensity, and prevents the coking of tubes from partial burning.