In this paper, we describe two approaches that consider CO2 recycle via utilization as a viable option to sequester carbon in CO2. First, we summarize the results of our study of the integration of CO2 capture with subsequent catalytic CO2 hydrogenation to methanol for application to stationary CO2-emitting sources. We carried out room temperature CO2 solubility studies in amines and glycol solvents that are normally used to separate CO2 from flue gas in power plants. In polyethylene glycol (Peg-400), the solubility data obey Henry's Law up to 4.5 MPa whereas in triethanolamine (TEA), the solubility is dominated by facile formation of the TEA.CO2 adduct at CO2 partial pressure as low as 0.33 MPa. Preliminary results on catalyst design and evaluation to affect the CO2/H2 reaction show that in these solvents, several transition metals are effective under mild conditions (T < 150°C and P < 5 MPa) for methanol synthesis though rates and product selectivity need further improvement. Second, we address the H2-cost issue that implicates geologic formations as natural slurry reactors for CO2 hydrogenation into liquid fuels wherein the needed H2 is produced from H2O by naturally occurring transition metals in these formations. A catalytic reaction then reduces the buried CO2 into H2-rich fuels. Successful development of the latter approach might close the natural carbon cycle in fossil fuels.
|Original language||English (US)|
|Number of pages||15|
|Journal||ACS Symposium Series|
|State||Published - Dec 1 2002|
All Science Journal Classification (ASJC) codes
- Chemical Engineering(all)