Chapter Ten Safety and Environmental Protection (泵的安全和环境保护).doc

Chapter Ten Safety and Environmental Protection Risk Analysis of the unit How to evaluate risk of unit? Answer: Generally, the risk of petrochemical unit is evaluated by hazard of raw material, amount of hazard material in unit, process conditions, process complex, operation mode, control method. Raw material of coking unit is residue, with process characteristics of high temperature and high sulfur. Therefore, main risk is fire hazard and poison damage. What is oil flash point? What is significance on flash point analysis? Answer: Under specific testing conditions, when oil is heating, flash point is the minimum temperature at which instant flashing is happened while mixture of steam from heated oil and air contacting with fire. Based on different measuring method and instrument, there are two measuring methods, such as open cup method and closed cup method. The former is used to measure heavy oil, and the latter is applicable for both light oil and heavy oil. Generally, the lower petroleum fraction boiling point is, the lower its flash point is. For example, flash point of gasoline is -30～-40℃; flash point of diesel oil is 26~50℃; and flash point of lube oil is 130～325℃. If heavy oil (lube oil) is mixed with the oil with low boiling point (gasoline or dissolvent), the flash point will be decreased significantly. Therefore, evenness of the oil (whether it is mixed with component with low boiling point) could be judged by flash point. Risk level of oil is classified by its flash point. For example, the oil with flash point at 45℃ and above is called as combustibles, and the oil with flash point at 45℃ and below is called as flammables. There is a relationship between flash point and chemical composition of the oil, i.e. the oil with much waxy hydrocarbon has a high flash point, but the equivalent oil with cyclic hydrocarbon-aromatic base including much colloid has a low flash point. What is range of explosion? How to calculate it? Answer: Not all mixture of oil