Effect of the N-methylmorpholine-N-oxide (NMMO) pretreatment on anaerobic digestion of forest residues

• Pretreatment of forest residues using N - methylmorpholine - N - oxide (NMMO or NMO) prior to anaer obic digestion was investigated , where the effects of particle size, NMMO concentration , and pretreatment time were the primary focus. The pretreatments were carried out on forest residues; with different particle size s of 2, 4 and 8 mm , at 120 °C for 3, 7 , and 15 h in two different modes of NMMO - treatment : dissolution by 85% NMMO and swelling without dissolution using 75% NMMO solution in water . The pretreatment process led to minor changes in the composition of the forest residues . The best improvement in methane yield of the forest residues was achieved by pretreatment using 85% NMMO for 15 h at 120 °C. This treatment resulted in 0.1 7 Nm 3 /kg VS methane yield , which corresponds to 83 % of the expected theoretical yield of carbohydrates present in the material. Additionally, the accumulated methane yield and the rate of the methane production were highly affected by the amounts of remaining NMMO when it was not well separated during the washing and filtration step s after the treatment. The p resence o f concentrations even as low as 0.008 % NMMO resulted in a decrease in the final methan e yield by 45% , while the presence of 1% of this solvent in the digester completely terminated the anaerobic digestion process.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Industriell bioteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Industrial Biotechnology (hsv//eng)

Nyckelord

Forest residues

NMMO

anaerobic digestion

inhibition

biogas

lignocelluloses

degradation

Biofuel

Resursåtervinning

Resource Recovery

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)