and environmental regulations make the processing of residua to light oils and
feedstocks for other units desirable and, indeed, necessary in many areas. Several
process approaches are available for resid conversion. In this chapter, we explore
several of the resid conversion processes, including thermal cracking, visbreaking,
delayed coking, Flexicoking™, deep oil FCC, and residuum hydrocracking.
A detailed design example of thermal cracker key equipment is provided.
Keywords
Refinery • Crude oil • Residuum • Resid • Coking • Visbreaking • Thermal
cracking • Fuel oil
Introduction
The highest yield of straight-run product as a percentage on crude is usually the
residue from the atmospheric distillation of the crude feed. In most Middle East
crudes, this ranges from around 40 vol.% for the lighter crude oils to 50 % and
higher in case of the heavier oils. It can be, and often is, the major factor in crude oil
slate selection and in the operation of the refinery itself. In most cases, a large
portion of the residue can be blended off to meet the fuel oil product in the
refinery’s production plan. In other cases, perhaps equally as common, a major
portion of the atmospheric residue is further distilled, under vacuum, to distillates
which can be processed to meet gasoline and middle distillate product slates or lube
oil blending stocks. The residue from this vacuum distillation, now considerably
smaller in volume, is routed to fuel oil or to a bitumen product pool.
There are cases however where the quantities of both atmospheric and vacuum
residues are high enough to limit the refinery’s throughput or limit its production of the
more valuable products and thus limit the refinery’s profitability. In such cases, the
conversion of these residues becomes attractive and, in some cases, absolutely imperative. This latter case refers to those refineries that have no or a very small fuel oil
market. The upgrading of these residues is accomplished by the indirect processing of
the atmospheric residue, processing the distillates by catalytic cracking or hydrocracking and then thermally cracking the vacuum residue. Most of the processes involved
with the conversion of the vacuum distillates are described in other chapters of this
handbook dealing with hydrocracking and fluid catalytic cracking.
Direct upgrading of the atmospheric residue by the thermal cracking processes
has long been the “workhorse” of the industry in processing the “bottom of the
barrel.” However, some catalytic processes have been developed which demonstrate a more efficient and effective method than the thermal cracking routes. This
chapter deals with the direct processing of crude oil residuum and is divided into the
following parts:
• Thermal cracking
• “Deep oil” fluid catalytic cracking
• Residuum hydrocracking and desulfurization
532
D.S.J. Jones
feedstocks for other units desirable and, indeed, necessary in many areas. Several
process approaches are available for resid conversion. In this chapter, we explore
several of the resid conversion processes, including thermal cracking, visbreaking,
delayed coking, Flexicoking™, deep oil FCC, and residuum hydrocracking.
A detailed design example of thermal cracker key equipment is provided.
Keywords
Refinery • Crude oil • Residuum • Resid • Coking • Visbreaking • Thermal
cracking • Fuel oil
Introduction
The highest yield of straight-run product as a percentage on crude is usually the
residue from the atmospheric distillation of the crude feed. In most Middle East
crudes, this ranges from around 40 vol.% for the lighter crude oils to 50 % and
higher in case of the heavier oils. It can be, and often is, the major factor in crude oil
slate selection and in the operation of the refinery itself. In most cases, a large
portion of the residue can be blended off to meet the fuel oil product in the
refinery’s production plan. In other cases, perhaps equally as common, a major
portion of the atmospheric residue is further distilled, under vacuum, to distillates
which can be processed to meet gasoline and middle distillate product slates or lube
oil blending stocks. The residue from this vacuum distillation, now considerably
smaller in volume, is routed to fuel oil or to a bitumen product pool.
There are cases however where the quantities of both atmospheric and vacuum
residues are high enough to limit the refinery’s throughput or limit its production of the
more valuable products and thus limit the refinery’s profitability. In such cases, the
conversion of these residues becomes attractive and, in some cases, absolutely imperative. This latter case refers to those refineries that have no or a very small fuel oil
market. The upgrading of these residues is accomplished by the indirect processing of
the atmospheric residue, processing the distillates by catalytic cracking or hydrocracking and then thermally cracking the vacuum residue. Most of the processes involved
with the conversion of the vacuum distillates are described in other chapters of this
handbook dealing with hydrocracking and fluid catalytic cracking.
Direct upgrading of the atmospheric residue by the thermal cracking processes
has long been the “workhorse” of the industry in processing the “bottom of the
barrel.” However, some catalytic processes have been developed which demonstrate a more efficient and effective method than the thermal cracking routes. This
chapter deals with the direct processing of crude oil residuum and is divided into the
following parts:
• Thermal cracking
• “Deep oil” fluid catalytic cracking
• Residuum hydrocracking and desulfurization
532
D.S.J. Jones