Black liquor gasification: 1. The impact of pressure on C-H-O-S gas speciation and tar components during pyrolysis

The effect of pressure on the pyrolysis behavior of a softwood kraft black liquor was investigated using IPST's pressurized laminar entrained-flow reactor in conjunction with NREL's transportable molecular beam mass spectrometer. In this preliminary work, runs were made in pure nitrogen at 800rectangleC; conditions favorable for production of tars. Pressures ranged from 2 to 10 bar, and particle residence times from 0.3 to 4 seconds. The main tar products were benzene, toluene, and naphthalene. Char production decreases with pressure from about 1 percent at one bar to about 0.3% at 10 bar. The peak hydrogen sulfide level decreases from about 20% of sulfur input at 1 bar to less than 2% at 10 bar.