Introduction - Spent Hydroprocessing Catalysts - page 4

Because of the stringent environmental regulations regarding all phases of handling and
disposal of spent hydroprocessing catalysts, research on the development of processes for
recycling and reutilization of these solid wastes has been receiving considerable attention.
Earlier studies on the environmental, disposal, and utilization aspects of spent refinery
catalysts have been reviewed by Furimsky [15] , Trimm [14] , and Clifford [21] . It should be
noted that these studies focused on different aspects of spent catalysts each and, therefore, they
are complementary. A review by Marafi and Stanislaus [22] , which was part I in the series of
two, covered spent catalyst waste minimization methods, and utilization to produce useful
materials (excluding metal recovery). The information available in the literature on spent
hydroprocessing catalyst waste reduction at source by using improved, more active and more
stable catalysts, regeneration, rejuvenation and reuse of deactivated catalysts in many cycles,
and reusing in other processes were reviewed in detail. Available methods for the preparation
of active new catalysts and the valuable products, such as fused alumina, synthetic aggregates,
anorthite glass-ceramics, refractory cement, etc., from spent hydroprocessing catalysts are also
reviewed in this paper focusing on recent developments. Another review by these authors [23]
focused on the progress in research on metal recovery from spent hydroprocessing catalysts
and treatment methods for safe disposal as well as on the recent developments in commercial
processes for metal recovery from spent catalysts.
The focus of this topic is on all aspects of spent hydroprocessing catalysts starting with their
generation on refinery site. All commercial activities and/or options, such as transportation,
regeneration, rejuvenation, metal reclamation, reprocessing and production of novel materials,
storage, and disposal are being evaluated in details. Special attention is paid to the
environmental and safety issues, including developments in regulatory affairs. Cursory
accounts of the events, which are responsible for the change of fresh catalysts into spent
catalysts, i.e., deactivations are presented as well. This is deemed to be desirable because the
subsequent treatment of spent catalysts is influenced by the extent of deactivation. In the
course of this project, the wealth of information on all aspects of spent hydroprocessing
catalysts in the technical and scientific literature has been noted. Growing interests in this topic
has been indicated by vigorous research activities in this field, in recent years. After
thoroughly evaluating all developments in petroleum refining and relevant environmental and
regulatory affairs, it was concluded that it is now a right time to have all this information
consolidated in a topic. In addition, as the result of more than two decades of involvement, the
authors gathered and have access to an only of its kind information from petroleum refineries
and in house research. Some of this information was not yet communicated. It is anticipated
that the topic will serve as a benchmark for developing strategic plans in petroleum refineries.
Regulatory authorities will benefit from various environmental and safety issues frequently
discussed in the topic. The topic may serve as the model for undertaking similar projects in
other sectors of chemical and petrochemical industry where catalysts may be used in
non-petroleum refining applications.