Browsing by Author "Pesola, Aino"
Now showing 1 - 7 of 7
- Results Per Page
- Sort Options
- Bioproducts from filtrate oxidation
Kemian tekniikan korkeakoulu | Master's thesis(2022-10-18) Heikkilä, Roni - Bioproducts from pulp mill side streams
Kemian tekniikan korkeakoulu | Master's thesis(2023-08-22) Hakim, Md Azizul - Combustion air flow measurement with airfoil instrument in recovery boilers
Kemian tekniikan korkeakoulu | Master's thesis(2021-01-26) Pesola, Aino - Integration of a novel technology into pulp mill fiberline
Kemian tekniikan korkeakoulu | Master's thesis(2022-12-13) Silfverberg, Anna - Life cycle of biocomposites: from raw materials to recycling
Kemiantekniikan korkeakoulu | Bachelor's thesis(2018-05-30) Pesola, Aino - Pulp mill filtrate oxidation
Kemian tekniikan korkeakoulu | Master's thesis(2024-05-21) Sairanen, JiahuiThe demand of methanol, one of the most widely traded chemicals, has been continuously growing. In order to achieve a sustainable bioeconomy, forest industry is promoting the utilization of methanol as a value-added by-product from pulping process, as methanol production in the kraft process can be as high as 15 kg/t of pulp. In kraft pulping, the majority of methanol is formed from xylan through elimination and from lignin through oxidative demethoxylation. Previous studies indicate that dissolved lignin present in pulp washing filtrates is a potential source of increasing the overall methanol yield further. According to literature, oxidative demethoxylation of lignin largely depends on several reaction parameters, such as oxygen pressure, mass transfer of oxygen, temperature, pH, and time. In this study, all the experiments were conducted without pH control, as the original filtrate pH levels were quite suitable for lignin oxidation. According to the results, the most important factors on methanol formation were filtrate type, followed by oxygen pressure, time and temperature. Methanol formation in the brown stock washing filtrates was more intensive compared to post-oxygen washing filtrates. The highest methanol formation in the oxidation of hardwood brown stock filtrates was 19.7 kg/t and the corresponding value for softwood filtrate was 8.6 kg/t. Basically, the methanol content could be tripled in hardwood and doubled in softwood brown stock filtrates compared to its original content. In addition, oxidation had a clear impact on filtrate characteristics. The harsher the condition, the more significant decrease of pH and dry matter content occurred, in turn the higher the methanol formation. However, the decrease of COD did not show a clear relationship with methanol formation. - Valorization of lignin from industrial sidestreams
School of Chemical Engineering | Master's thesis(2024-12-30) Dar, AzamThe potential of producing value added renewable products has gained a lot of hype. This thesis investigates the non-catalytic high-pressure oxidation of lignin derived from kraft pulping side streams and digestate from biogas plants focusing on sustainable methanol production and valorization of industrial byproducts. Experiments were conducted at 90°C for 2 h with lignin solutions, digestate solutions and filtrates adjusted to different alkaline pH, exploring the effects of oxygen pressure and alkali consumption on methanol yield. This study aims to establish optimal conditions for maximizing methanol and carboxylic acids output while minimizing alkali consumption to make the process more economically viable. The findings reveal that phenolic lignin primarily contributes to methanol production through oxidative demethoxylation, while non-phenolic lignin undergoes additional degradation to yield carboxylic acids and smaller aliphatic compounds. Sulfur species in filtrates were oxidized to stable forms, reducing environmental risks associated with these effluents. A lower alkalinity demonstrated comparable methanol yields to strongly alkaline pH, with significantly reduced alkali requirements, highlighting potential industrial and environmental benefits. This research highlights the feasibility of achieving comparable methanol yields at lower alkalinity and high oxygen pressure while significantly reducing alkali usage, contributing to environmental sustainability and economic viability. Key parameters, including oxygen pressure and reaction pH, were identified as critical for reaction efficiency. GC-FID, HPLC, and FTIR analyses validated the conversion of lignin into methanol and carboxylic acids, while spectroscopic methods confirmed lignin degradation. This research contributes to the development of scalable, sustainable methods for lignin valorization, aligning with circular economy principles by transforming industrial side streams into high-value products like methanol. This study provides a scalable pathway for reducing alkali inputs, minimizing environmental impacts, and improving the economic feasibility of lignin valorization.