PINCH ANALYSIS FOR OPTIMISATION OF HYDROGEN NETWORKS

Abstract

Hydrogen has emerged as a very important feedstock fuel in the recent centuries. Especially for refineries and petrochemical industries, hydrogen is a key component in different processes and affects the economics of these industries significantly. With the stringent environmental rules, refineries are forced to produce low sulfur fuels. One of the most critical issues in low sulfur fuel is managing the impact of the new requirements on the refinery hydrogen balance. The combination of low sulfur fuel specification to reduce production of hydrogen in catalytic reformers and the desire, process heavier more sour crude make hydrogen balance a critical issue. Generating, recovering and purchasing hydrogen have a significant impact on the refinery operating cost. To effectively analyse the hydrogen balance and to suggest its proper use, new mathematical rules are required. A literature search clearly indicates that very little work has been done in this field. The only work which available suggest that the hydrogen network and management problem can be tackled using process integration techniques thar are developed for tackling of heat and mass exchange network. Conceptually the modification of this technique should help to tackle such problem. Keeping the above drawback in mind the present work has been taken to meet the hydrogen balance requirement in a refinery by managing its hydrogen sources (like CRU, Import, hydrogen and plant, lubricant units, HCU, KHT, NHT CCHT,CNHT, DHT, etc) k hydrogen sinks (like lubricant units, HCU, KHT, NHT CCHT,CNHT, DHT, etc). For this purpose a base (Towler 1996) refinery having a capacity of crude handling equal to 1655 m3/hr/Import deal of 649 iii mol/s was taken in to consideration. The base case was improved in terms of its operating parameter, hydrogen enriching units, and PSA network connectivity using modified pinch technology for mass exchange network (MEN). By this improvement the import bill of 649.0 molls was reduced to 497.08 mob's.