Environmental Engineering Reference
In-Depth Information
CHAPTER 5
Environmental and Safety Aspects of Spent
Hydroprocessing Catalysts
The survey of wastes generated by US petroleum refineries, conducted in 1992 under auspices
of the American Petroleum Institute (API), grouped refinery wastes into six categories, i.e.,
aqueous wastes, oily sludge, waste chemicals, contaminated soil, other wastes, and spent
catalysts
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. As part of this survey, almost all participants indicated a steady decline in
generation of refinery wastes. As hazardous solid wastes, spent hydroprocessing catalysts
come under the controlling terms of the US Environmental Protection Agency (EPA), Basel
Convention, and Organization for Economic Cooperation and Development (OECD) rules. As
such, the spent catalysts cannot be exported to third world countries. Furthermore, the
generators have a legal obligation to ensure that their spent catalysts are properly disposed of
or safely recycled. Since spent hydroprocessing catalysts have been classified as hazardous
wastes, their safe handling and disposal in an environmentally acceptable way is an issue of a
great and continuous concern for petroleum refiners.
The process of handling spent hydroprocessing catalysts begins with their removal from
reactors at the end of the operation. The procedures described in operating manuals are applied
by refiners during the catalyst withdrawal from reactors and subsequent treatment on refinery
site. Special precautions have to be taken in the case that spent catalysts are transferred to a
treatment, storage, and disposal facility. All these actions and/or activities are governed by a
set of environmental and safety regulations. The objective is to minimize an adverse effect of
spent catalysts on the quality of ambient air and ground water. In the following sections, all
phases of spent catalysts handling and movement will be discussed in line with the existing
regulations.
Refineries have to spend a sizeable portion of their cash flow in order to comply with
environmental regulations. As a consequence, some refineries had no choice but to shut down
the operation. Because environmental regulations are still evolving, refineries may be
experiencing such pressures continuously. A competitive advantage may be gained by
refineries or countries with a lower environmental awareness. Therefore, some global
approach to deal with environmental and safety issues in petroleum refining industry is needed
to prevent an unfair competition.
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