Greenhouse Gas emissions reduction by process intensification: Reactive distillation column with side decanter

Direct hydration of cyclohexene to produce cyclohexanol is the industrial process with a lower

raw material cost but with a quite expensive process. Large energy consumption is consequence

of large cyclohexene recycle related with its unfavourable chemical equilibrium. This study corroborates

that the Asahi process is a good candidate for intensification avoiding the cyclohexene

recycle. Rigorous simulation shows that a single reactive distillation column, with a side decanter,

operated at total reflux, allows overcoming the chemical equilibrium limitations as the product is

continuously collected by the column bottoms and the heat of reaction is directly used to

separate the product by distillation. The novel process is studied and compared to the classical

Asahi process. An energy comparison with the available processes proposed in the literature is

performed. Therefore, achieving more energy-efficient processes leads to lowering their environmental

impact, thus decreasing the carbon dioxide emissions. Applying the proposed methodology

for cyclohexanol production, more than 67,000 t CO2/y emissions can be avoided

compared to the nowadays used classical process, thus the potential savings applying process

intensification to the chemical industry are very large and worth further investigation.