Abstract

To strive to achieve a greener environment for the well being of Canadian citizens and residents, Canadian environmental regulatory agencies continue to promulgate more stringent standards for sulfur emissions from processing facilities of Oil &Gas Production, Petrochemical and Refining industries. Due to these stringent sulfur emissions regulations, operation reliability of sulfur recovery facility becomes vital to warrant continuous daily overall plant operation. It is therefore important for operators to understand the relevant sulfur issues to facilitate their selection and implementation of proper advanced, reliable and cost effective technologies for sulfur recovery to ensure continuous, reliable and smooth plant operation, thus achieving and maintaining a greener environment.

This paper focuses on key advanced technologies for cost effective conversion and recovery of H2S from gas streams to elemental sulfur. Technology and design considerations in handling contaminants contained in the feed gases, in enhancing overall sulfur recovery efficiency and in increasing processing capacity will be addressed in this paper. The following key considerations will be dealt with in detail in the paper.

  • Quality and compositions of acid gases: Cost effective technologies to handle contaminants such ammonia, Benzene, Toluene and Xylene (BTX), and cyanides etc.

  • Sulfur Recovery Efficiency Enhancement: Cost effective technology and optimum process configurations for revamping existing units and installing new units in enhancing sulfur recovery efficiency.

  • Cost effective solutions for expanding processing capacity of existing sulfur plants.

To absolutely minimize the sulfur emissions and in the interest of operation personnel safety, increasing activities in recovering H2S and entrained elemental sulfur from vent gases purged from sulfur pits, sulfur storage tanks and sulfur tank car loading/unloading facilities are seen in refining and gas processing facilities. Regulatory requirements for such recovery impose interesting challenges for operators and designers. This paper addresses various technology options for accomplishing the desired sulfur recovery in meeting the regulatory requirements. Pros and cons of these various technology options will be discussed in this paper.

This paper also provides an overview of short term and long term economic implications in utilizing and implementing these advanced technologies.

Introduction

In the wake of the global warming and acid rain issues, environmental regulatory agencies around the globe continue to promulgate more stringent standards for sulfur emissions from processing facilities of Oil &Gas Production, Petrochemical and Refining industries. Sulfur emission regulations govern both single point emission source such as the sulfur recovery plant and a bubble source such as the entire processing facility. These regulations in Canada require new plants to achieve sulfur recovery in the range of 98.5 to 99.7 percent. It is expected that these standards will become more stringent in the future. The Alberta Energy and Utilities Board (EUB) and Alberta Environment (AENV) believe that "sulfur recovery requirements represent minimum expectations and that it is in the public interest for operators of sour gas plants to implement continuous improvement programs to reduce emissions. Particularly in the case of grandfathered sour gas plants, operators are encouraged to take cost-effective measures early to enhance sulfur recovery beyond the minimum requirements discussed in Section 3.1 of Interim Directive ID 2001–3 (italics added)."1 It is advisable to select and implement

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