Optimal hydrogen production through revamping a naphtha-reforming unit: Catalyst deactivation

Generating the necessary volume of hydrogen to produce high-quality gasoline has become a critical issue in some refineries, where an important hydrogen source is an old semi-regenerative catalytic naphtha-reforming unit. We studied the possibility ofredesigning this unit to obtain an additional similar to 0.1 millon of standard cubic metric per day of hydrogen while fulfilling the 15 ppm sulfur specification with the refurbished naphtha hydrotreater. The reforming unit (which has three equal-size reactors in series) was simulated using a previously developed kinetic lump model and a new catalyst deactivation model. The constants for the apparent kinetics model were adjusted using commercial data from one cycle of operation. The deactivation model was developed on the basis of pilot-plant and commercial data from an operating unit. The constants for both models were obtained using a genetic algorithm. The integrated model was used to both estimate the impact of including a new reactor and optimize existing reactor configuration. In addition, the model included redesigning the heater, debutanizer, and recycle compressor. The simulation indicated that optimal hydrogen production depends upon catalyst deactivation, cost of revamping, reactor configuration, and integration to the refinery. The optimal economical cycle length was obtained for a particular set of reactor volumes and additional naphtha throughput.