Abstract
With depletion and natural decline of the sour gas fields in Germany, many conventional gas sweetening plants have been abandoned for economic reasons. A study and a concept selection were conducted to identify technical and economical competitive methods for a pilot plant, compared to existing conventional sweetening plants.
Several technical literature sources, patents and processes licensed by third parties have been researched. 58 methods were identified for sour gas sweetening, 8 methods for sulfur recovery and 9 methods for tail gas treatment. These were quantitatively ranked in a decision matrix. Plant concepts were developed, and basis of design were created with the technology owners for the three most promising processes. CAPEX was determined with the vendors input. OPEX were estimated using the basis of design.
Sour gas sweetening via amines is a reliable and cost-effective method. The focus of this paper is therefore on sulfur recovery and tail gas treatment. The tail gas treatment can be eliminated by highly efficient production of elemental sulfur, sulfuric acid or gypsum directly from the sour gas sweetening unit. This leads to halving of CAPEX.
Production of wet sulfuric acid via contact process using an innovative reactor is favorized. This modular plant can be integrated in existing sweetening plants (brownfield) or used for new installations (greenfield). Due to the fully automated process and high availability, OPEX can be significantly reduced.
This work uses a structured method to screen the available processes and to rank them according to the given requirements. The evaluation method can be used for other boundary conditions. Production of sulfuric acid directly from the sweetening unit could increase the lifespan of sour gas wells.
