The Study Of N-Tetracosane And Crude Oil Cracking With Water

Water is available in geological condition and it is important in the formation and cracking of crude oil. By the lab experiment on the n-tetracosane and crude oil with different kinds of saltwater using gold tube-confined system and the measurement of the gaseous and liquid hydrocarbons generated, the roles of water and its salinity in them are analyzed. The main conclusion is as follows:1. It is revealed that the differences between the yields of gaseous alkanes generated from n-tetracosane and crude oil cracking with water and without water are much small. However, the yields of liquid n-alkanes vary much large with heated time delaying because water appears. The further analysis of liquid n-alkanes generated from n-tetracosane cracking with water shows that water can change the rate constant of the formation reaction of liquid n-alkanes and makes them reach their yield maximum early.2. Compare with those of n-alkenes generated from n-tetracosane and crude oil cracking without water, the yields of n-alkenes generated with water are much larger. And when the salinity of saltwater reaches a certain value, the yields of n-alkenes decrease rapidly. The ratio of n-alkene/n-alkane can indicate the salinity of water in certain degree. Lower the ratio, the salinity is higher. No liquid n-alkenes were observed in the liquid products generated from crude oil cracking.3. Water does not make an obvious impression on the carbon isotope values of gaseous and liquid n-alkanes generated from n-tetracosane and crude oil cracking and the differences between theδ¹³C values of the n-alkanes generated with and without water are no more than 1‰. There is no evidence of obvious hydrogen isotope exchange between water and n-tetracosane and crude oil and the alkanes generated from them. Water still makes a role in the hydrogen isotope of gaseous and liquid n-alkane generated. TheδD values of the gaseous alkanes generated n-tetracosane and crude oil cracking with pure water is lighter than those without water. TheδD values of liquid n-alkanes generated from n-tetracosane cracking with pure is heaviest and theδD values of liquid n-alkanes generated with saltwater is much similar to those without water. TheδD values of liquid n-alkanes generated from crude oil cracking with water is lighter than those of liquid n-alkanes generated from crude oil cracking without water.This work supplies a theoretic basis for the further study of crude oil crackingand the appraisal of the cracking gas from crude oil.