Unveiling TMP Process Water Potential As an Industrial Sourcing of Valuable Lignin–Carbohydrate Complexes toward Zero-Waste Biorefineries

Abstract

The development of zero waste biorefineries is a promising yet challenging pathway towards a sustainable bioeconomy. Deep insights on the composition of biorefineries side streams along with the development of green technologies are mandatory to achieve such goal. In this paper, a sustainable pilote scale membrane process was used to recover valuable organic matter dissolved in the main side stream of a thermomechanical pulping (TMP) plant. A great number of analytical tools were combined to get an extensive characterisation of the generated fraction, including ICP-AES, HPIC-PAD, FTIR, SEC, 13

Lignin Carbohydrate Complexes structure preserved throughout downstream processes for their valorization after recovery from industrial process water

“…The dissolved LCCs were recovered from 3 m 3 of process water using pilote-scale flotation and filtration units ( Figure 1) as previously reported. 17 The LCC rich fraction was recovered after ultrafiltration on the 1 kDa membrane.…”

“…Ultrafiltration of the process water discarded from thermomechanical treatment (TMP) also demonstrated to lead to an interesting sourcing of LCCs characterized by their well-preserved native structure. 17 While LCCs potential for industrial applications is most of the time assessed right after their isolation at lab-scale, further downstream processes (DSP) will have to be taken into consideration for preservation and transportation purposes before their incorporation into final industrial products. Such downstream treatments often suggest heat exposure of the product whereas hemicelluloses and lignin structures present poor thermal stability.…”

“…Such extensive heat-sensitivity underlines the importance of selecting and optimizing appropriate DSP in order to preserve the LCCs structure during their production phase. 17 Different DSP were then applied including moist heat sterilization, simple effect evaporation for concentration under reduced pressure and spray-drying. Analytical tools were combined to provide a deep chemical and structural characterization of the LCCs along these processes.…”

Recovery of lignin and lignans enriched fractions from thermomechanical pulp mill process water through membrane separation technology: Pilot-plant study and techno-economic assessment

“…Membrane technology is a sustainable, soft and clean process where the separation does not have extensive heat or chemicals requirements. This latter advantage leads to end products of high quality, and makes it easier to comply with the many stringent requirements from both consumers and public authorities (Steinmetz et al, 2019). Many studies report the use of membrane technology for TMP waters fractionation for galactoglucomannans (GGM) valorisation as biopolymer for example (Persson and Jönsson, 2010a;Thuvander and Jönsson, 2016) whereas only two studies had the objective of lignin and extractives valorisation (Persson et al, 2010b;Courbalay et al, 2018b).…”

“…29 % of lignin and 70 % of lignans were retained with the 300 Da membrane. Both fractions still contained hemicelluloses with concentration of 15 g.L -1 in 1 kDa retentate and part of hemicelluloses were free GGM as another part was linked to a part of lignin content to form LCC Steinmetz et al (2019). have proposed the following composition in 1 kDa retentate of thermomechanical process water: 40 % of LCC, 35 % of GGM, 7 % of free lignin, 8 % of ash and 10 % of others (included lignans content).…”