Evaluation of a Light Ends Fractionation System for Alternative Hydrocarbon Feedstocks

EVALUATION OF A LIGHT ENDS FRACTIONATION SYSTEM FOR ALTERNATIVE HYDROCARBONS FEEDSTOCKS

Process Engineering Associates, LLC (PROCESS) was contracted by the client, a producer of aerosol propellants, to evaluate the production of high purity light end hydrocarbon products using a new fractionation system under construction at their facility.  This new system was originally designed by PROCESS for high purity propylene production.  The client was interested in determining alternative uses for the unit to maximize use of available spare capacity.

PROCESS performed the following tasks in support of this effort:

• Using PROCESS‘ licensed commercial computer process simulation software the fractionation system was modeled for the production of propane, iso-butane, and normal-butane.

• Based on the specified product assays, the columns’ operating parameters including feed stage, feed rate, pressure, reflux rate, and reboiler heat duty were varied to maximize the overall recovery and throughput.   The operating conditions were bound by the capacity of the tower internals and simulation results were used to assess and verify that hydraulic loading was maintained within the design range.

• For each product, various configurations were considered to determine the appropriate use of the available columns.  Additionally, both single-pass and two-pass re-distillation options were considered for some products.  For each case, process parameters were manipulated to maximize column throughput within the confines of the available equipment.

• Equipment specifications were reviewed for each product at the new operating conditions.  This included evaluations of tower internals, heat exchanger ratings, pumps, restrictive orifices, vessel nozzles, equipment pressure and temperature ratings, and utility system loads.

The operating conditions and equipment limitations determined in the study were summarized in a letter report submitted to the client.  The results showed production of all products was possible with only minor system modifications.