Thermodynamic Analysis of Isosynthesis Reaction

Isobutene is important in the industry as it is used as an intermediate product or direct raw material to produce many chemicals. The primary production method for light olefins is steam cracking of petroleum-based (insufficient resource) naphtha. The steam cracking method consumes a lot of energy, causes serious harmful emissions, and poses a fire and explosion hazard if adequate safety precautions are not taken. Obtaining isobutene from synthesis gas, an alternative source, is important in eliminating the mentioned energy, environmental, and safety problems.

In this study, thermodynamic analysis of the reaction of obtaining isobutene from synthesis gas, which has strategic importance, was aimed by using the traditional stoichiometric method.

Matlab program was used in the solution of the equation sets. The effects of temperature(400-1000K), pressure (1-50atm) and feed composition (Case 1: 50%CO+ 50%H₂ Case 2: 60%CO+ 40%H₂, Case 3: 70%CO+ 30% H₂) on CO conversion and isobutene yield values ​​were investigated.

As expected for the relevant reaction, it was observed that the equilibrium conversions decreased with temperature due to the exothermic nature of the reaction. It was shown that isobutene yields exhibited a similar behavior. It was also shown that pressure change had as serious an effect on conversion and yield values ​​as temperature. H₂-rich feed composition positively affected CO conversion and isobutene yields. Again, in a H₂- rich feed composition, higher conversions (>90%) and yields (⁓25%) were detected at relatively low-pressure operations (5atm).

It is anticipated that the study will contribute to the development of catalysts and chemical reactor designs for isosynthesis reactions.