Speight J. (ed.) The Desulfurization of Heavy Oils and Residua

2 edition. — CRC Press, 1999. — 480 p.The sulfur content of petroleum varies from less than 0.05 to more than 14 wt% but generally falls in the range 1 to 4 wt%. Petroleum with less than 1 wt% sulfur is referred to as low-sulfur, and that with more than 1 wt% sulfur is referred to as high-sulfur. The refining industry considers heavy oils, residua, and bitumen to be high-sulfur feedstocks. Hence they are the focus of many conversion and desulfurization scenarios.Little has changed in this respect since the publication of the first edition of this book. Indeed, there has been a tendency over the past decade for the quality of crude oil feedstocks to deteriorate — the average refinery feedstock is of lower API gravity and higher sulfur content than the average refinery feedstock of ten years ago. This means higher quantities of residua, more heavy oils, and higher quantities of sulfur to remove.The success of the first edition of this text has been the primary factor in the decision to publish the second edition, which has been greatly expanded and rewritten to be more in keeping with the technological aspects of the petroleum industry. There are also expanded updates on the nature of the constituents of the asphaltene fraction of petroleum to show the means by which such constituents might influence desulfurization activity.Since the first edition of this book, there have been many changes in the refining industry. The overall character of the feedstocks entering refineries has changed to such an extent that the difference can be measured by a decrease of several points on the API gravity scale. There is also more detailed information on the nature of the other nonhydrocarbon constituents of petroleum as well as a section on how these particular constituents behave during refinery operations. Such behavior can seriously influence the life of the catalysts that are used for desulfurization processes. One chapter deals with refining chemistry so that the reader can obtain a better understanding of the chemistry involved in the processing of heavy feedstocks and the fate of the sulfur in these feedstocks. In addition, environmental issues have become of such importance that a chapter on the cleanup of refinery gases is included. And the environmental effects of sulfur-containing gases are also addressed.This edition has references cited throughout the text, in contrast to the first edition, which contained a general bibliography at the end of each chapter. The cited references will guide the reader to the original article for more detail. Although there are many thousands of references in my personal files, no attempt has been made to include them all. I have selected those that might give the reader the most information.Among other changes from the first edition, the book has been reorganized. Each chapter has been written as a standalone entity to spare the reader the inconvenience of having to refer to different parts of the book for discussions of a given topic. This has necessitated, for convenience, the duplication of some of the tables and figures. However, such duplication has been kept to a minimum.In addition, petroleum refining has entered a significant transition period as the industry moves into the twenty-first century. Refinery operations have evolved to include a range of next-generation processes as the demand for transportation fuels and fuel oil has shown steady growth. These processes are different from one another in terms of the method and product slates and will find use in refineries according to their respective features. The primary goal of these processes is to convert the heavy feedstocks to lower-boiling products, and during the conversion there is the benefit of a reduction in sulfur content. Thus, these processes need to be given some consideration. A separate chapter is therefore included in which these more modern processes for upgrading heavy feedstocks are described.Finally, it is time to acknowledge the organizations that have also contributed to this book. The following oil companies provided photographs of refinery operations: Phillips Petroleum, Sinclair Refinery, Shell Oil, Sun Oil, and Chevron Oil are gratefully acknowledged for their contributions. Some of these pictures have appeared in The Chemistry and Technology of Petroleum (Marcel Dekker, Inc.) and it is appropriate that several also appear here. I am grateful to those persons who supplied the pictures.Finally, I am indebted to my numerous colleagues in many different countries who made constructive comments on the first edition. These comments have been of great assistance in writing this volume and I am truly grateful.