-----Original Message----- > HH: Possibly a better way to go is to use oxygen to burn the power plant fuel and recycle 100% of the CO2 through algae. Then run the power plant on the algae, its oil, cellulose and all. No coal necessary at all. No sequestration necessary. The byproduct, a lot of liquid nitrogen ....
Horace, it gets even better than that. You do not need cryogenics or nitrogen storage and distribution. These options have been tossed around in the past. There are a number of techniques for enriching air in O2 from about 80/20 to about 50/50 with minimal energy expenditure. Unless the value of the nitrogen can be made higher, then full separation of the gases through cryogenics, or pressure swing techniques, etc is far too energy intensive to make that feasible. With the most efficient low pressure blower - the so-called squirrel-cage type, you can move tons of air per hour very cheaply, and in the process use permanent magnets (in combination with selective membranes) to play on the very high magnetic susceptibility of O2 compared to N2. There are quite a few patents and also studies like this: http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TVM-4M221KK-C&_us er=10&_rdoc=1&_fmt=&_orig=search&_sort=d&_docanchor=&view=c&_searchStrId=962 541556&_rerunOrigin=google&_acct=C000050221&_version=1&_urlVersion=0&_userid =10&md5=3b66ddc35ecf90947310ba1c670e3ca2 Actually some nitrogen is preferable in the exhaust - especially for Algae growth in those strains used for food purposes, so the 50/50 mix is good. The net exhaust gas has been reduced in volume considerably, the net proportion of CO2 increased and it makes for a tidier system. In terms of "societal value" and especially if we avoid all coal (with its toxic ash like arsenic) I think we would be better off growing an algae strain that is high in food protein and lower in lipids. If the plant operator must use coal, then a strain with higher lipids would be preferable, of course; but if the plant operator knows that he will be able to reduce the net tonnage of new carbon purchased, by up to 2/3 even with food algae, then it makes shifting away from coal more palatable ... "palatable" being the operative word. The value of protein should always be much higher (in the big picture of 6 billion humans) than the value of cellulosic biomass. Therefore, even if an even-swap is made (for humanitarian reasons) that is to say: algae for biomass - then the results of having the increased high quality food available to feed both humans and farm animals is highly beneficial. Of course, planning-ahead with that kind of 'big picture' foresight, is not something that capitalism does very well. Jones
