DESIGN OF MEMBRANE BASED HYDROGEN RECOVERY UNIT AT UREA PLANT-1 FFC

Abstract

Urea production requires the reaction of ammonia and carbon dioxide. The production of ammonia, itself, is a complex process that requires several steps. Ammonia is produced by introducing a synthesis gas, which is comprised of hydrogen, nitrogen and inert byproducts like methane and argon, into a catalytic reactor. In the Ammonia production synthesis loop, the conversion of the reactor is very low in a single pass, so the process requires the components to be looped through a cycle. A purge stream is taken out of the synthesis loop to get rid of these built-up inert byproducts in the recycled stream. This purge also contains high concentrations of valuable gases such as hydrogen and ammonia. According to economic and environmental aspects, it is beneficial to recover these gases rather than burning them. After recovery, hydrogen is recycled back to the synthesis loop, which not only reduces the amount of natural gas required as raw material but also enhances the production efficiency. As per the industrial directive, a detailed study has been carried out to propose a suitable process to recover ammonia and to use Membrane Separators for the recovery of hydrogen. Material and Energy Balance, Equipment Design, Simulation, Instrumentation and Process Control and a comprehensive Economic Analysis has been performed to provide the industry with a viable process to enhance the overall ammonia production by recovering hydrogen using Membrane Separation Technology.