Over the years, the increasing prices of crude oil and environmental issues have been the major factors for the development of GTL technology. With over 910 Tcf of natural gas reserves in Qatar (gas-in-place and recoverable resources), there is tremendous capacity for additional GTL plants in Qatar. Out of the global projected GTL production of 1.92 million B/d, Qatar alone already has planned to produce 696,000 B/d (36% of total global production). One of the efficient ways of using the exothermic heat from GTL is for desalination. This helps in reducing a large quantity of the fresh fuel to be used as energy input for desalination.
The need for this study is to investigate the availability of exothermic heat from the Gas-To-Liquids (GTL) process to desalinate seawater thereby producing substantial volumes for industrial and/or domestic sectors. This is performed by first designing a schematic base case model of the GTL operation using Aspen Plus. The quantity and quality of heat available from the cooling of the syngas and syncrude streams is used as the energy source for the desalination process. Both thermal desalination and reverse osmosis processes are considered to determine the optimal process for desalination. An integrated GTL-Desalination (GTL-D) process is later designed to compare the output ratio of the GTL-D as opposed to a standalone desalination process.
The global GTL production projected by the year 2011 is 1.92 million bbl/day and out of this Qatar alone has planned to contribute a liquid production of 696,000 bbl/day (Chedid et al., 2007), which is around 36% of the total production. This is seemingly possible due to the abundant reserves (gas-in-place and recoverable) located in the North Field region of Qatar. Currently Oryx GTL (joint venture between Sasol and Qatar Petroleum) produces 34,000 bbl/day and plans to produce 130,000 bbl/day by 2010. Shell along with Qatar Petroleum is starting up the world's largest integrated GTL project which will produce 140,000 bbl/day. This shows tremendous potential for the development of more GTL plants and in Qatar.
The need for water is increasing tremendously every year that it is becoming scarce in so many regions. Usually heat is imported from external sources or burning fuel to produce the energy required for desalination. Integration of plants with desalination systems is a very good option in conserving energy and helps in being more economical. Integration can be done with several systems like acid manufacturing plants, refineries and any exothermic process. In our study, we focus on integrating gas-to-liquid (GTL) plant with a desalination system by quantifying the excess available heat to generate electric power to run a reverse osmosis system.