Optimal design and plantwide control of novel processes for di-n-pentyl ether production

BACKGROUND: Di-n-pentyl ether (DNPE) is a good candidate for diesel fuel formulations due to its blending cetane number, good cold flow properties and effectiveness in reducing diesel exhaust emissions, particulates and smokes. However, novel processes are required in order to drive the production costs down and to increase the efficiency at industrial scale. RESULTS: The dehydration of 1-pentanol to yield DNPE is catalyzed by thermally stable resins, such as Amberlyst 70 which has high activity and selectivity at temperatures up to 190 °C. Two process options are proposed for a plant capacity of 26.5 ktpy: a reaction-separation-recycle (R-S-R) system based on an adiabatic tubular reactor and a catalytic distillation process. Both processes were optimized in terms of total annual costs (481 and 523 k$ year^-1), leading to specific energy requirements of 225 and 256 kWh ton^-1 DNPE, respectively. The controllability was assessed by dynamic simulation performed in Aspen Dynamics. CONCLUSION: Compared with the membrane reactor reported earlier, the new DNPE process alternatives (i.e. conventional reaction-separation-recycle system and catalytic distillation) are better process candidates, requiring simpler units leading to much smaller investment costs, while also having good controllability.