Talk:Coal plant conversion projects
For all plants using torrefacted biomass: Torrefaction or mild pyrolysis is an exotherm process generating more heat than required. Its offgas can be used to dry materials or, in case of already dry materials, generated some extra electricity, generate some high value chemicals along.
Not to overload with references: http://www.ecn.nl/news/item/date/2010/04/02/ecns-torrefaction-technology-has-proven-itself-in-an-endurance-test/
Reference  in original text isn't a very good source to make a judgement on the torrefaction process.
"Biomass also presents other issues. In terms of emissions, it releases approximately the same amount of particulate matter as coal and fifty percent more carbon monoxide and carbon dioxide"
Technology for burning biomass is definitly different from coal burning. Boilers and furnances are build to specification of fuel and switch of fuel does mean switch of technology. Biomass can't be burned in portion more than 20% in direct combustion coal fired installations. However, torrefacted biomass has nearly the same chemical specifications (or better, lower ash, low sulfur, no mercury) and same mechanical properties (grindability etc).
Use same techniques as in coal fired direct combustion, the particulate matter will be lower (less ash) and there should be no difference in CO and CO2 levels. In general combustion of biomass will contain less CO as the mass itself does contain quite some extra oxygen itself. It might emit slightly more flue gasses per kg combusted material but it is not said that this will contain more CO2 per volume. Perhaps even less as a larger part of the energy is from reducing the hydrogen with oxygen to water vapor.