Trends in desulfurization capabilities, processing technologies, and the availability of crude oils: U. S. refineries; Caribbean ''exporting'' refineries

A review of all U.S. refineries and their downstream equipment has led to the conclusion that slightly more than 40 percent of the existing capacity can handle some sour crude of one type or another. For various reasons, this cannot be an exactly defined number, nor does it coincide with the percent of hydroprocessing equipment in relation to crude capacity. A few refineries have hydrotreating facilities and yet only have sweet crude capability. A few refiners may only have capability to handle sour crudes in the lower sulfur ranges, say 0.5 to 1.0 percent, due to emissions problems or other limitations. These are limitations which can be overcome by investments. Still others would face problems in their product output pattern due to low gravity of some sour crudes. Catalytic hydroprocessing (hydrocracking, hydrorefining, and hydrotreating) removes sulfur from refinery streams so that the total amount of sulfur in the products and residues is less than that in the crude oil feedstock. For this reason, changes in hydroprocessing capacity are used to express the changing capabilities of refiners to process sour crudes. On the other hand, thermal processes (vacuum distillation, visbreaking, and coking), segregate most of the sulfur contained in the refinery feedstocks into residual fractions, allowing the production of low sulfur containing products, but the total amount of sulfur in the products and in the residual fractions is essentially the same as that in the crude oil feedstocks. In this regard, thermal processes are limited in their ability to produce low-sulfur products.