This paper reports on the Shell GTL technology and design, its operation and products.
The process is based on the Fischer Tropsch conversion of synthesis gas in multi-tubular reactors over a proprietary catalyst, followed by hydro-conversion and distillation. The synthesis gas is produced by partial oxidation of natural gas with pure oxygen in the Shell Gasification Process. Critical design features and performance of these main process steps are discussed.
A GTL complex is much more than just the sum of its individual process steps. The high level of integration of process and utilities poses many challenges to reliability and efficiency of operation of the complex. Important learning of eleven years of Bintulu operation will be shared. It gives insight in what makes GTL technology safe, efficient and reliable. These lessons have been implemented in the design of the 140,000 bbl/d GTL plant, which Shell is planning to realize together with QP in Qatar.
The Bintulu plant provides valuable experience in producing synthetic GTL products. A concise review will be presented. Understanding of the relationship between plant operation and product slate and – properties has been obtained, completed by experience of subsequent product performance in different applications. When new GTL capacity comes on-stream in the Middle East larger volumes of GTL product will become available to both bulk users and niche markets.
The Shell's GTL technology consists of three basic stages:
The 1st stage is the production of the synthesis gas from the partial oxidation process of natural gas with pure oxygen via the Shell Gasification Process (SGP), in combination with a Steam Methane Reformer (SMR). This combination enables a reliable, energy efficient and cost effective design for syngas production of the right composition.
The 2nd stage is the Heavy Paraffin Synthesis (HPS), where the synthesis gas is converted into paraffin molecules. The process is a modern version of the Fischer Tropsch synthesis invented in Germany in the 1920s to produce liquid hydrocarbons from coal derived synthesis gas.
The 3rd and final stage comprises of hydroconversion and distillation steps to convert the intermediate HPS product into high quality products.