A sample set such possible areas of improvement and innovations are discussed in the section that follows.
Value upgradation schemes
For instance, Coker Gasoil (CGO) is usually a special cut appearing above coke and below the Coker diesel cut. While its usual disposition is to Fuel Oil for viscosity cutting, an alternate possibility is to consider it as a feed to Catalytic crackers and Hydrocrackers by which its value gets upgraded to a VGO feedstock from a Fuel Oil feedstock. Of course, the process limitations of considering CGO (higher ‘S’, heavier feed) as a feed to FCC/HCR and also economics of replacing CGO with a distillate (Kero/Diesel) stream for Fuel Oil Viscosity cutting has to be studied.
Similarly, LCO and HCO from the FCC are usually considered for Fuel Oil viscosity cutting. However, they can serve as good hydro-treator feedstock for a refinery not limited by hydrogen but having spare hydro-treating capacity as these streams have large concentration of aromatic sulphur compounds which consume incremental quantities of H2 compared to SR diesel for every unit of feed processed.
Preferential feedstock balancing
For instance, consider a refinery which has a Coker unit in place and also has a Kero hydro-treator whose capacity doesn’t suffice enough to treat all the Coker Kero and the SR Kero from the CDU’s. Also, the Fuel Viscosity cutting has to be done with the help of either SR Kero or Coker Kero. Now, we have two destinations and two streams to map profitably. From process point of view, hydrotreating SR kero is much simpler compared to Coker Kero. However, the FO viscosity cutting will be very sharp with SR kero compared to Coker Kero. Therefore, the pros and cons are to be weighed in such a situation to balance the feedstock in order to drive maximum profitability and operational feasibility.
Prioritization of Hydrogen consumption
Often, in a H2 starving refinery, the challenge always lies in deciding and arriving at H2 distribution to various consumers. Consider a situation where, the catalytic reformer has gone for an emergency shut-down making the refinery devoid of internal hydrogen generation and hence the only source of H2 is that bought from external sources. With the recent changes in energy parity for H2 pricing, cost of sourcing hydrogen from external sources has almost doubled. In this context, the question arises as to utilize the available H2 for Hydro-treating (or) Hydrocracking purposes. Usually, running an LP case-comparison with latest demands and prices in place can help us in arriving at a choice based on the Diesel Vs Kero crack margin.
Make Vs Buy decision making
Producing Gasoline in-house Vs Purchasing Gasoline from outside market is always a point of concern. This is often governed by the Gasoline Vs Naphtha price differential. The crack should be strong enough to cover the operating costs involved in running the catalytic reformer. Of course, the H2 generation from reformer also adds as a factor to the overall economics.Apart from these we have Cut-point optimization, process parameter tweaking, synergic inter-refinery transfers for better capacity utilization as some of the other potential areas for Profit improvement in refineries.