Utilizing nuclear process heat to reduce the CO2 generated by an SMR process in a GTL environment

Abstract

Gas to liquids (GTL) technology, although an attractive method for meeting liquid fuel requirements into the future, has an inherent concern regarding the environmental impact of dealing with the large amount of carbon dioxide that is generated. In this investigation, the potential to reduce this carbon dioxide footprint by utilising process heat from high temperature helium at 950oC downstream of a High Temperature Gas (cooled) Reactor (HTGR) is examined. The study compares a base case steam methane reformer (SMR) heated by the combustion of natural gas to a nuclear heated steam methane reformer heated by hot helium from one HTGR. It has been shown that it is possible to reduce the carbon dioxide footprint almost entirely for the synthesis block of a GTL facility. Process heat integration from one HTGR has the potential to reduce the carbon dioxide footprint of an SMR by approximately 42 tons per hour. The full potential of one HTGR in terms of carbon dioxide reduction for a GTL facility was also investigated. This was achieved by estimating the cogeneration potential impact on carbon dioxide emissions where the residual heat in the helium stream downstream of the reformer was used for power generation. The overall amount of carbon dioxide reduction from both the reformer and power generation facility was then quantified and an economic study was completed. The study shows that with one HTGR it would be possible to reduce the carbon dioxide emissions of a GTL facility by almost 200 t/h if nuclear process heat was used in the reformer and nuclear power generation was used instead of conventional coal based power generation. Results from the economic study show that industry would have to incur an operating cost increase of approximately R200, at current natural gas prices, to reduce their carbon dioxide emissions by one ton if nuclear energy was used as a process heat source and for power generation.