Optimal design of alkane pyrolysis processes: propane pyrolysis

Abstract

A two-stage optimal design procedure is suggested for alkane pyrolysis processes and is applied to propane pyrolysis. The first stage considers only hydrocarbon decomposition, the primary reaction in the process. A mathematical model consisting of an overall stoichiometric, an empirical rate, and a heat-balance and hydrodynamic equation is constructed. This model is analyzed for a varied tube diameter and a fixed propane conversion to optimize the design parameters of the propane pyrolysis reactor. At the second stage, the main reaction is considered together with secondary and tertiary reactions and a complete model taking into account recycling of the unreacted raw material is constructed. The optimum inlet temperature and recycle ratio are determined as a function of the total feed rate. An economic optimality criterion is suggested, and final process optimization is carried out.

Natural Gas Pyrolysis in a Liquid Metal Bubble Column Reaction System—Part II: Pyrolysis Experiments and Discussion

“…Contrary to the decrease in the maximum ethane molar fraction, the ethene molar fraction of the product gas from the nGH pyrolysis obtained at 1223 K had increased by a factor of two compared to the ethene molar fraction of the MEM pyrolysis product gas (Figure 12). A possible explanation for the higher molar fraction of ethene in the product gas during the nGH pyrolysis at 1223 K is the enhanced ethene formation during the pyrolysis of higher hydrocarbons, which has been described several times in the literature [11,28,30].…”