Handbook of Petroleum Processing

This introduction to crude oil and petroleum processing provides a working knowledge of crude oil properties and refining to make the large array of petroleum-based products we enjoy today. Topics include the composition of crude oil, the crude assay, product properties, and the basic processes used to convert crude to useful products. This chapter sets the stage for the detailed discussions, descriptions, and calculation methods contained in the balance of this handbook.

This chapter defines the major products normally produced from the refining of crude oil. These products are the intermediates and finished products from energy refineries. The “Introduction to Crude Oil and Petroleum Processing” chapter of this book provided a brief description of the products; this chapter expands on this with a more in-depth look at the products themselves. Their demand in the petroleum markets and also the environmental impact of the more prominent products are also discussed in this chapter. The chapter continues with a discussion of the types of refinery configurations, including yields, capabilities, economics, advantages, and disadvantages of the common configuration categories. The chapter concludes with a detailed example of the development of the process configuration for a refinery to meet a particular product slate.

Crude oil received by a refinery is initially distilled or fractionated into multiple “cuts” by boiling range. These cuts are further processed into final products in the refinery units. This chapter describes the initial crude fractionation process in both atmospheric and vacuum distillation units and how these units are designed. Detailed example design calculations are provided.

The “light ends” unit is the only process in a refinery configuration that is designed to separate “almost” pure components from the crude oil. Its growth initially resulted from the need of those components such as butanes and propanes to satisfy a market of portable cooking fuel and industrial fuels. The need for modern gasolines has added to the demand for light ends to make high-octane blending components. This chapter describes the process and design of units to separate the light ends into useful products or into cuts for further processing in the refinery. An example design is provided.

Catalytic naphtha reforming is a major process in the petroleum refinery that converts low value naphthas into high-octane reformate product for gasoline blending and into high-value aromatics for petrochemical processing. Catalytic reforming also provides valuable hydrogen for hydroprocessing units to produce clean fuels. In the reforming process, naphthas rich in paraffins and naphthenes are converted mainly to aromatic hydrocarbons by contacting with a platinum-containing acidic catalyst at elevated temperatures and pressures. This chapter will briefly review the history of catalytic reforming and then describe the naphtha feed properties, market trends, reforming reactions, catalysts, deactivation mechanisms, catalyst regeneration, unit diagrams, process conditions and economics.

The catalytic cracking process, commercialized in 1942, has undergone numerous changes. It is the most important refinery process in that it converts the heavy portion of the crude barrel into transportation fuels. The main changes in catalysts, equipment and operations are covered along with the versatility of the process to handle a wide variety of feeds and produce the desired products. The FCCU is the bridge between refining and petrochemicals and the new FCC processes that fill this gap are presented here.

Hydrocracking is a flexible catalytic refining process that can upgrade a large variety of petroleum fractions. Hydrocracking is commonly applied to upgrade the heavier fractions obtained from the distillation of crude oils, including residue. The process adds hydrogen which improves the hydrogen to carbon ratio of the net reactor effluent, removes impurities like sulfur to produce a product that meets the environmental specifications, and converts the heavy feed to a desired boiling range. The chemistry involves the conversion of heavy molecular weight compounds to lower molecular weight compounds through carbon-carbon bond breaking and hydrogen addition. The main products have lower boiling points, are highly saturated, and generally range from heavy diesel to light naphtha. Hydrocracking processes are designed for, and run at, a variety of conditions. The process design will depend on many factors such as feed type, desired cycle length, and the desired product slate. Hydrocracking is a process that is suitable to produce products that meet or exceed all of the present environmental regulations. Hydrocracking reactions proceed through a bifunctional mechanism. Two distinct types of catalytic sites are required to catalyze the steps in the reaction sequence. The cracking and isomerization reactions take place on the acidic support. The acid can be an amorphous silica alumina or a zeolite. The metals provide the hydrogenation function. The metals are typically noble metal (palladium, platinum) or non-noble metal sulfides from group VIA (molybdenum, tungsten) and group VIIA (cobalt, nickel).Catalyst manufacturing can be done by a variety of methods. The method chosen represents a balance between the manufacturing cost and the degree to which the desired chemical and physical properties are achieved. Many companies are involved in the licensing of the process and the production of a variety of hydrocracking catalysts.

Hydrotreating or catalytic hydrogen treating removes objectionable materials from petroleum fractions by selectively reacting these materials with hydrogen in a reactor at relatively high temperatures and at moderate pressures. These objectionable materials include, but are not solely limited to, sulfur, nitrogen, olefins, and aromatics. The lighter distillates, such as naphtha, are generally treated for subsequent processing in catalytic reforming units, and the heavier distillates, ranging from jet fuels to heavy vacuum gas oils, are treated to meet strict product quality specifications or for use as feedstocks elsewhere in the refinery. Hydrotreating is also used for upgrading the quality of atmospheric and vacuum resids by reducing their sulfur and organometallic levels. Hydrotreaters are designed for and run at a variety of conditions depending on many factors such as feed type, desired cycle length, and expected quality of the products. Until about 1980, hydrotreating was a licensed technology being offered by a fairly large number of companies. From 1980 until the end of the last century, hydrotreating catalysts were becoming more commoditized as the formulations were less differentiated among the various suppliers. Many of the product quality specifications are driven by environmental regulations, and these regulations are becoming more stringent every year. With the advent of ultra-low-sulfur fuel regulations ushering in the first decade of the twenty-first century, however, it was required for hydrotreating research and development to deliver quantum improvements in catalyst performance and process technology. This was accomplished in the form of so-called Type II supported transition metal sulfide (TMS) catalysts, unsupported/bulk TMS catalysts, improved bed grading catalysts and stacking strategies, advanced catalyst loading techniques, improved trickle-flow reactor internals designs, and more effective catalyst activation methodologies.

Motor fuel alkylation in the petroleum refining industry refers to the acid-catalyzed conversion of C₃-C₅ olefins with isobutane into highly branched C5-C12 isoparaffins collectively called alkylate, a valuable gasoline blending component. Alkylation reactions are catalyzed by liquid and solid acids. HF alkylation and sulfuric acid alkylation are the most widely practiced commercial motor fuel alkylation processes and are the focus of this section. In recent years, considerable development effort has gone into solid acid catalysts and processes that mitigate the hazards associated with HF and H2SO4. Several of these processes have been offered commercially, but have not caught on because of high recycle isobutane requirements and high capital costs associated with catalyst regeneration. A new wave of ionic liquid catalysts is currently nearing commercialization.

Catalytic olefin condensation is the reaction of two or more olefinic compounds to form a heavier olefinic product. Several acid catalyst are used including solid phosphoric acid, organometallic catalysts, silica alumina, zeolites, and sulfonic acid resins. The primary application is to produce high octane gasoline from propene, butenes, or pentenes and more recently to produce distillates. Petrochemical operations include the production of 1-butene, heptenes, nonenes, cumene and ethylbenzene.

Upgrading light hydrocarbon (C₄–C₇) streams in refineries, petrochemical plants, and gas processing plants has continued to increase in commercial application, as the world demand for gasoline and petrochemicals has experienced steady growth over the past decade. Increasingly stringent regulations have been enacted in most regions of the world, driving the increased demand for clean fuels. As a result, gasoline composition has been adjusted to a greater extent using C₅–C₇ isomerization processes. Light-naphtha isomerization technology plays a key role in meeting octane demand in the gasoline pool for clean fuels and premium gasoline grades. Low octane naphtha feedstocks are processed into isomerate with an octane number ranging from 80 to 93 RON. Isomerization involves the skeletal isomerization of a paraffin to a more highly branched paraffin with the same carbon number. Several light paraffin isomerization technologies are reviewed in this chapter, including both process and catalyst technologies. Flow schemes and economics are reviewed. Catalyst technologies include Pt containing zeolitic, mixed-metal oxide, and chlorided alumina.

Refinery gas treating removes the so called “acid gases” (hydrogen sulfide and carbon dioxide) from the refinery gas streams. Removal of the acid gases in the refinery streams is required either to purify a gas stream for further use in a process or for environmental reasons. This chapter describes the most common sour gas treating processes. Design techniques are provided for the amine-based approaches along with a design example.

Crude oils usually contain substantial yields of heavy hydrocarbons boiling above 600–800 °F. These are referred to as atmospheric and vacuum residual oils, residua, or resids. Resids were primarily used for many years as heavy fuel oils (bunker oil) or various tar or asphalt products. Modern refinery economics 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.

As refinery product specifications become more stringent to meet environmental requirements, refinery demand for hydrogen has continually increased to supply the required hydroprocessing units. Additional improvements in burning qualities, like cetane, also require more hydrogen. This chapter addresses the processes used to make and/or recover hydrogen for petroleum processing applications. The processes described here include naphtha catalytic reforming, steam-methane reforming, hydrogen recovery, partial oxidation, gasification, olefins cracking, and electrolysis as they relate to hydrogen. Some basic methods for overall refinery hydrogen optimization and management are also described.

This chapter is concerned mostly with the laboratory testing for the control of petroleum products. It will be concerned with those tests that establish the quality of refinery streams and in some finished and salable products. What are not covered are those specialized tests such as mass spectrometry, motor road tests, and the like. Where possible sketches of test apparatus are included. Most of these tests are performed in the refinery laboratory and generally follow the methods provided by the respective ASTM numbered tests.

This chapter is divided more or less into three parts. The first part (section “Refinery Operation Planning”) deals with the planning of a refinery’s operation, which includes its optimized crude runs, product slate, and any process expansion or debottlenecking that may be required to meet this optimized operation. The second part (sections “Process Evaluation and Economic Analysis,” “Discounted Cash Flow and Economic analysis,” and “Using Linear Programming to Optimize Configurations”) deals with the process economic evaluation of a proposed new refinery or new facilities within an existing refinery. (The execution of the capital project is discussed in the chapter “Petroleum processing projects” elsewhere in this Handbook.) The third part (section “Common and Expressions Used in Standard Economic Analyses”) is a summary of common terms and expressions used in a standard economic analysis.

There are many activities carried out by a company in installing a new or revamped facility. Much of the initial work in executing a project is carried out by the company’s development engineers in a series of “Front End Loading” (FEL) stages to help insure the right facility is being built with the right economics. The discussion of project economics in the handbook chapter on economics and planning meshes with the FEL efforts. Once the facility is well-defined, the company will establish a team to execute the project. This chapter details the steps in project execution starting at the FEL stage and continuing through detailed design, guarantees, and into on-stream operation.

Not all refineries are aimed at producing fuels. This chapter focuses on two significant types of non-energy facilities: (1) lube oil refineries and (2) petrochemical refineries. In the lube oil discussion, we explore the nature of lubes and the various process routes used to make them. Routes include conventional deasphalting and extraction, hydroprocessing, Fisher-Tropsch synthesis, and oligomerization. Related to lubes, we explore the production of asphalt, with a process discussion and an example design. In petrochemicals, an aromatics complex is described, along with the processes used to make the typical BTX streams.

Prior to major discovery of crude oil, during the 19th and early part of 20th century chemicals from coal was a well established practice. From 1040s and beyond availability f low cost crude oil and expanding refining capacity industry switched to crude oil based feed stocks. However, by 1990 due to significant increase in crude oil price the industry started looking into conversion of low cost coal and natural gas for the production of petrochemicals. This chapter discusses some of the modern technologies of coal and natural gas conversion to chemicals.

In addition to the numerous conventional crude oils marketed, there are several types of “unconventional” crudes or feedstocks that a refinery may process. These are unconventional in that they are produced by methods other than typical exploration and production techniques. This chapter discusses the sources, properties, and processing characteristics of several unconventional stocks, including shale oil, shale crude, bitumens, extra heavy oils, synthetic crudes, gas- or carbon-to-liquids stocks, renewable feedstocks, recycled lube oil, transmix, and tank farm stocks.

Relatively recent interest in biofuels is rooted in the growing concern over rising global greenhouse gas emissions, energy independence, and support of agricultural industries. Although biofuels are still a small segment of the fuels industry, technologies that convert biomass into biofuels are widely being developed for industrial-scale application, and are expected to play an increasingly important role going forward. This chapter gives a broad overview of the major biofuels conversion pathways including fermentation both from plant sugars and lignocellulose-derived sugars, biodiesel, hydroprocessing of vegetable and animal oils, gasification, pyrolysis, and liquefaction. Special attention is given to hydrotreating and hydroisomerization of vegetable and animal oils due to its prevalence in industry, and its strong relationship with similar petroleum hydroprocessing covered in other chapters in this handbook. Life cycle analysis, measurement of biologically-derived carbon, and issues of integration of biofuels into fuel supplies that are still largely petroleum-based are also discussed.

This chapter focuses on the control systems which support the refining processes. This is not a definitive work on control systems, but paints the applications of control systems in a modern refinery with a broad brush. The material in this chapter starts with a discussion of control system architecture and continues with detailed descriptions of the major types of parameters controlled: flow, temperature, pressure, level, and composition. Additional material is provided on specific, common control situations. There is a brief discussion of control theory and there are procedures provided for sizing control valves. Numerous references are available for further information.

All oil refineries and other petroleum processing facilities need utilities in order to function. The common utility systems include steam, fuel, various waters, air, electrical power, and sewers, among others. This chapter explores the processes, design, reliability, and operation of these critical systems.

In a refinery, “offsites” are the facilities outside the main refining units that support those process units. The discussion in this chapter focuses on storage tanks, product blending, loading and receiving, waste hydrocarbon disposal, and effluent water treating. A procedure and example are provided for estimating tank heat loss and heater sizing.

Operating a petroleum processing facility cleanly is a requirement for doing business. The environmental regulations that affect refineries and other facilities have become increasingly restrictive and the trend is expected to continue. This chapter explores the range of relevant regulations, processes, and practices that apply to modern refineries and other petroleum processing facilities for environmental management. Topics include air emissions, water effluents, solid wastes, and noise. Detailed design examples are provided for a sour water stripper and an oil/water separator.

The processing of petroleum can be an inherently hazardous activity. The processes we use are handling a flammable material. They use strong, often hazardous, chemicals and employ high pressures and temperatures to convert the oil into finished products. All these factors present safety risks for both personnel and those living near a process facility. Still, the industry experiences very few incidents while processing millions of barrels of oil each day. Refineries place a high value on safety. This chapter discusses four key areas which contribute toward safety performance: personal protective equipment and systems, Process Safety Management (PSM), pressure safety, and temperature safety. A relief valve sizing example is presented.

Although the fire hazard is always a primary concern in the refining of petroleum, there are other hazards present that need to be addressed. Among these are the handling of some of the chemicals that are used or generated in the refining processes. This chapter provides general information on the hazards and handling of several chemicals. The information is not intended to substitute for regulatory, local, or company standards or medical expertise. Included here, are discussions of: amines, ammonia, benzene, carbon monoxide, catalysts and sorbents, caustic soda, furfural, hydrofluoric acid, hydrogen, hydrogen sulfide, methyl ethyl ketone, nickel carbonyl, nitrogen, sulfiding chemicals, and sulfuric acid.

Because refineries handle large quantities of highly combustible materials, fire and explosion are constant risks that must be managed. Refineries are designed to minimize the risks through proper specifications and fire prevention measures by design. Should a fire occur, however, a facility has extensive firefighting capabilities, including fixed and portable firefighting equipment, extinguishers, and an Incident Command System (ICS). These systems help in response to other incidents, such as releases and medical emergencies as well. This chapter addresses these issues, from design through operations.

This chapter deals with the equipment normally found in the petroleum refining industry. Many of the items that will be described and discussed here are also common to other process industries. Knowledge of these equipment items is essential for good refinery design, operation, and troubleshooting when necessary. The equipment and process design calculations described here include vessels, fractionators, pumps, compressors, heat exchangers, fired heaters, and piping and packed bed pressure drops. Several examples of these calculations are provided.

This dictionary provides definitions and background information on hundreds of abbreviations, acronyms, expressions, and terms used in the oil industry. Special emphasis is placed on refining and petroleum processing. References are provided for more detailed discussions of most of these terms elsewhere in this handbook.

This appendix is a collection of working flow sheet examples that are developed for design and operation of refinery and other petroleum processing units. These are only used as illustrations of the format and content for these key documents. Included here are a Process Flow Diagram and accompanying Material Balance, a section of a Mechanical Flow Diagram (or P&ID), and a section of a Utility Flow Sheet.

This appendix provides general data for petroleum processing which is used throughout this handbook. Included here are data on (1) viscosity and density/SG of stocks as a function of temperature; (2) relationships for chords, diameters, and areas of circular cross-sections that are used in vessel and tower design; and (3) boiling and freezing points for normal alkanes or paraffins up to a carbon number of 120.

This appendix provides a selection of several simple crude assays for stocks worldwide. It is intended to illustrate the range of variability and typical assay values. Caution: For final studies and definitive engineering, up-to-date assays from the crude oil suppliers should be used. The assays here are believed to be from reliable public sources, but they should be used only for informational purposes.

This appendix provides general conversion factors, pressure conversions, and viscosity conversions for petroleum processing. These factors are used throughout this handbook.