GAS TO LIQUID TECHNOLOGY

Introduction It  is  a  truism  to  observe  that  the  world's  hydrocarbon  resources  like  oil and  natural  gas  are  not  evenly  distributed,  and  in  particular  that  a substantial proportion of known reserves are situated in locations remote from  areas  of  high  consumption.  Transportation  of  liquid  hydrocarbons from  source  to  consumer  is  a  task  for  which  a  large  and  flexible infrastructure  exists.  However,  where  natural  gas  deposits  in  remote locations  are  to  be  exploited,  the  transportation  task  becomes  a  major challenge - particularly if geography, economics or a combination of both precludes the possibility of a pipeline. Countries in the Middle East, for example,  have  huge  reserves  of  natural  gas  but  little  local  market  for  it and   no   pipeline   infrastructure   to   ship   it   to   larger   economies.   This challenge can be met by conversion of natural gas into a transportable and saleable form or product. Historically this has implied LNG, ammonia or methanol  as  the  medium  of  bringing  remote  natural  gas  to  the  market place.  Each  of  these  has  its  limitations  -  the  heavy  investment  and, relatively   speaking,   small   number   of   receiving   terminals   limits   the marketing  flexibility  for  LNG.  Neither  the  ammonia  nor  the  methanol market  is  large  enough  to  accept  the  potential  volumes  available  from exploitable natural gas reserves. Current prices for both products would indicate  that  we  are  close  to  these  marketing  limits  -  unless  of  course legislation drives motor fuels in the direction of methanol. An alternative which is gaining increasing attention is the conversion of natural gas to liquids  -  ranging  from  gasoline  to  middle  distillates  (GTL  fuels)  by  the GTL Technology. This approach avoids the infrastructural limitations of LNG and at the same time provides a market large enough to accept the potential volumes. Basic   GTL   technology   was   invented   in   1923,   when   two   German scientists,  Franz  Fischer  and  Hans  Tropsch,  discovered  the  catalytic conversion   of   carbon   monoxide   and   hydrogen   (synthesis   gas)   into synthetic  hydrocarbons.  The  GTL  process  involves  feeding  pipeline- quality  natural  gas  (methane)  into  a  reformer  or  generator  where  it  is converted  into  synthesis  gas  (a  combination  of  carbon  monoxide  and hydrogen). This technology is similar to processes used for years to make methanol  and  ammonia.  Then  the  synthesis  gas  is  processed  through  a Fischer-Tropsch  reactor  where  it  is  converted  into  GTL  fuels  (synthetic crude). Fischer-Tropsch chemical reaction process is therefore the core of this technology.