Production of Polymer Grade Ethylene via the Oxidative Dehydrogenation of Ethane

  • Baneet Saini
  • Camilo Sanchez Quesada
  • Zhenrui Lin
  • Samin Arnob

Abstract

This report provides an overview of the oxidative dehydrogenation (ODH) process and detailed design for the production of 800 thousand tonnes/annum of ethylene through oxidative dehydrogenation using a feed source consisting of ethane and oxygen. Included in this report are the descriptions of main process units, material and energy balances, an economic analysis of the process, detailed engineering design, specification sheets, P&IDs of relevant equipment, plot plan of the facility, and a review of safety and environmental concerns. A wall-cooled multi-tube packed-bed-reactor with a Ni-Nb-O catalyst operating at 400 °C and 3000 kPa is selected to carry out the ODH reaction. The reactor effluent, composed of ethane, ethylene, water, and carbon dioxide is separated through compression, cooling and multiple two-phase separators, an amine sweetening system, a two-column temperature swing adsorption unit, and a distillation column; an ethane/propane refrigeration system provides the necessary cooling for the distillation unit. A final ethylene product that has a purity of 99.9% is stored and sold into a product pipeline. A Process Flow Diagram is included to show the equipment and major units in the process, and a Stream Table is provided to act as the material and energy balance for the process. The process flow diagram and P&IDs are in Appendices B and E, respectively. An economic analysis performed for the process shows a total Fixed Capital Cost of $361M, payback period of 6.3 years, and a Net Present Value of $218.48M after 20 years of operation. The most expensive units in the process were found to be the compressors ($55M), the steam turbine ($29M), and the ODH reactor (24M).  Due to the handling of flammable materials throughout the process, the greatest hazard identified is that of an explosive atmosphere that would be formed after a loss of containment. Besides combustion products from utilities and flaring, there are no major environmental concerns associated with the operation of the process, the yearly GHG emissions for the process are 161.43 ktCO2eq. An included Gantt Chart outlines the design steps taken in the completion of this project. 

Published
2020-06-17