Publication Date:
2012-02-23
Description:
Huge amounts of CH4 bound in natural gas hydrates lead to the idea of using hydrate bearing sediments as an energy resource. Natural gas hydrates remain stable as long as they are in mechanical, thermal and chemical equilibrium with their environments. Thus, for the production of gas from hydrate bearing sediments, at least one of these equilibrium states must be disturbed by depressurization, thermal stimulation or addition of chemicals such as CO2. In the framework of the German national gas hydrate research project SUGAR (Submarine Gas Hydrate Reservoirs), all three reaction routes – alone or in combination – are tested. The aim is to find the most flexible and efficient, but also environmentally friendly method for gas production from hydrates. One method in this context is the thermal stimulation using in situ combustion. Therefore, a heat exchange reactor was designed and tested for the catalytic oxidation of methane. Furthermore, a large scale reservoir simulator (Volume 425 l) was realized, to synthesize hydrates in sediments under conditions similar to nature and to test the efficiency of the reactor. Thermocouples placed in the reservoir simulator collect data regarding the expansion of the heat front, respectively. These data are used for numerical simulations for up scaling from laboratory to field conditions. However, thermal stimulation may be used alone or in combination with CO2 sequestration. Therefore, laboratory studies on the methane production from pure hydrate phases as well as hydrate bearing sediments by use of CO2 injection are investigated using several analytic tools such as Nuclear Magnetic Resonance spectroscopy, confocal Raman spectroscopy and X-ray diffraction.
In this study we present the experimental set up of the large scale reservoir simulator and the reactor design. Preliminary results show that the catalytic oxidation of CH4 in a countercurrent heat exchange reactor operated as a temperature controlled, autothermal reaction outside of the flammability limits of CH4 is a safe and promising tool for the thermal stimulation of hydrates. In addition, preliminary results from the laboratory studies on the CO2-CH4 swapping process in pure and pore-filling gas hydrates are presented focussing on the kinetics of this process.
Type:
Conference or Workshop Item
,
NonPeerReviewed
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