FuBio – Production of hydroxy acids and products thereof Workshop Groupwork: Recovery from kraft pulp mill process Group leader Raimo Alén, JYU

Recovery from kraft pulp mill process (results of the workshop Dec 10th, 2010) Feedstocks (both softwood and hardwood delignification) – Black liquor (BL) – Effluent from alkaline pretreatment (EAP) chips  alkaline preatreatment  cooking – Effluent from oxygen delignification – Hydrolysate from hot-water pretreatment of chips prior to cooking

Recovery from kraft pulp mill process (results of the workshop Dec 10th, 2010) Unit operations – The "first" group carbonation (lignin precipitation) Carb electrodialysis (recovery of natrium, acid) ED ion exclusion chromatography (separation of individual acids) IEC distillation (separation of individual acids) D ultrafiltration (separation of lignin) – The "second group" extraction (novel solution) adsorption (acids and lignin) esterification plus distillation use of ion exchanges crystallisation (only for pure fractions, not for BL) Define the benefits and disadvantages of main unit operations

Recovery from kraft pulp mill process (results of the workshop Dec 10th, 2010) Some process alternatives – separation/recovery process integration to the current process with minimal changes – important issues when considering process alternatives material balance sodium recovery the effect of separation method to fibres how much each component will be produced? the effect on BL thermal value the effect on production efficiency (in case recovery boiler is a bottleneck) possibility to produce acetic and formic acid There are a great number of possible process modifications and alternatives!

Recovery from kraft pulp mill process (results of the workshop Dec 10th, 2010) Principles for the process outline – Fibre is the main product – Efficient recovery of cooking chemicals and extractives – Sulfur-free novel by-products Suitable balance between the carbohydrate and lignin degradation products Straightforward separation techniques Versatile modification possibilities

Recovery from kraft pulp mill process (results of the workshop Dec 10th, 2010) BL ED NaOH Free acids Distillation IEC BL residue UF Distillation etc. Behaviour of extractives, lignin, sulfur containing inorganics? i) Simplest solution BL Carb CO 2 UF not an option, H 2 S! Lignin NaHCO 3 /Na 2 CO 3 - acids as Na-salts - part of lignin left (<15 % of original amount) - inorganic compounds ED distillation IEC +H 2 SO 4 distillation IEC UF XAD Na-salts

Recovery from kraft pulp mill process (results of the workshop Dec 10th, 2010) Wood Pretreatment NaOHPulping - kraft -soda-AQ Turpentine Evaporation Crude tall oil Carbonation Evaporation Fuel gas CO 2 Lignin (~75 % of total) NaHCO 3 / Na 2 CO 3 Acidification Evaporation H 2 SO 4 Lignin (~15 % of total) Volatile acids Na 2 SO 4 Crude hydroxy acid fraction Basic process Variable part

Recovery from kraft pulp mill process (results of the workshop Dec 10th, 2010) EAP (effluent from alkaline pretreatment) – the same way as BL – positive: no sulfur – the effect on pulp (fibre) quality? – Na-recovery (material balance) OED (effluent from oxygen delignification) – same way as EAP PHWT-hydrolysis

Recovery from kraft pulp mill process (results of the workshop Dec 10th, 2010) Patent and other IPR –questions – patent and literature review is done by VTT (Black liquor ja hydroksihapot, June 2010) Other potential companies? – Hycail (Turku) – polymerisation of hydroxy acids – Rinheat Oy (Otaniemi), process calculations, also ED