Use of biomass-derived glycerol as an alternative to fossil fuels for aniline production: Energy saving and environmental aspects

Abstract

Catalytic reduction of nitrobenzene is the leading technological step in aniline production. The hydrogen required for this stage, is dominantly produced from fossil fuels through reforming processes, which take much energy and emit large amounts of CO2. Biomass-derived glycerol steam reforming is an attractive alternative to traditional reforming to reduce the dependence on hydrocarbon resources and mitigate climate change. This research aims to analyze a mass- and heat-integrated multi-tubular membrane reactor, containing nitrobenzene hydrogenation (exothermic-side) and glycerol steam reforming (endothermic-side) for co-production of aniline and syngas. In this process, hydrogenation reaction acts as a heat source for glycerol reforming, while hydrogen produced in the endothermic-side simultaneously permeates through the membrane, reacts with nitrobenzene to produce aniline and enhances the equilibrium glycerol conversion. Besides, the steam produced in the exothermic-side is continuously recycled to the entrance of the endothermic-side. The role of different parameters on reactor performance is realized using a heterogeneous model. Numerical results show that by adjusting the adequate operating conditions, glycerol and nitrobenzene conversion above 80% and syngas with H2/CO ratio in the range of 2.0–2.5, suitable for Fischer-Tropsch and methanol synthesis processes, can be achieved. In addition, this integrated process is promising in terms of energy saving, environmental pollution mitigation, feasibility and effectiveness for industrial-scale application; however, experimental proof-of-concept is required to ensure the safe operability of this process.