Ethylene plays an essential role in petrochemical industry. Recovering ethylene from refinery dry gas is becoming increasingly important. Recently, hydration is proposed as a new method of separating ethylene from dry gas. This work builds the hydrate formation reactor model and simulates a process scale flow chart, which includes hydrate formation, absorption and cryogenic distillation. Economic evaluations are also performed. The optimal operating conditions and minimum total annual cost are found via optimization. Based on an industrial example, a butane absorption system is also simulated and evaluated. The total annual cost of the two process are compared and the cost distribution profiles are analyzed. Results show that the proposed absorption-hydration hybrid process (AHHP) is economically advantageous over the current butane absorption process. Major cost of butane absorption origins from column reboiler duty, whereas cost of the proposed AHHP mainly comes from compressor and hydrate formation refrigeration. Hence, if refrigeration from hydrate dissociation is reused, a significant portion of utility could be saved. In future work, refrigeration recovery techniques would become another meaningful topic for hydrate based gas separation. (c) 2016 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.