Ultrafiltration of lignin slurry
Mäkelä, Emmi (2017)
Mäkelä, Emmi
Tampereen ammattikorkeakoulu
2017
All rights reserved
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:amk-2017121521536
https://urn.fi/URN:NBN:fi:amk-2017121521536
Tiivistelmä
This thesis consists of theory and experimental parts. The theory concentrates on the lignin, ultrafiltration and in its advantages and applications. The experimental part shows results for different membranes used in ultrafiltration through figures and comparisons. The laboratory results complete the overall results. The work was done for Valmet Technologies Oy and the tests were conducted in Valmet’s R&D Center in Messukylä, Tampere.
The first purpose of this study was to gather information on different membranes and their possible advantages to ultrafiltration and hydrothermal carbonization (HTC) process. The aim was to decide whether ultrafiltration affects the lignin slurry and how the behavior of the membranes varies compared to each other. The second aim of this thesis was to increase the yield in lignin slurry by ultrafiltration technology provided by Valmet.
The trials were done with Valmet’s Optifilter CR250/2 and various membranes. First, results were gathered from five different membrane combinations in recycling, concentration and dilution stages. Then, a concentration trial was conducted and finally, laboratory results were made. The results were then compared.
The results show that P and RC membranes compared to P10 and P20 membranes give similar laboratory results. The concentration trials show that there are differences between these membranes in permeate flux rates. P10 and P20 membranes are tighter compared to P and RC membranes and therefore the differences are explained. It takes more time to filtrate with P10 and P20 membranes, which can affect the expenses in the used processes. The yield in lignin slurry is higher in the concentrate, but in the permeate fluxes the dry solids are reduced.
In conclusion, both mentioned membrane combinations give similar results and there is no big difference to be seen. Ultrafiltration has many advantages and it is preferred to be used in HTC process as well. These results, however, need more studying to confirm what combination works the best. More stable conditions should also be created in order to achieve more reliable results. Temperature can be controlled, which would have an effect on the overall results. The particle sizes of the permeate fluxes after filtrating with different membranes would have been interesting to see. These can be predicted from the membranes pore size, but the shape of the particle cannot be seen. Altogether, the both aims of the study were fulfilled and the behaviors of the membranes are compared and discussed.
The first purpose of this study was to gather information on different membranes and their possible advantages to ultrafiltration and hydrothermal carbonization (HTC) process. The aim was to decide whether ultrafiltration affects the lignin slurry and how the behavior of the membranes varies compared to each other. The second aim of this thesis was to increase the yield in lignin slurry by ultrafiltration technology provided by Valmet.
The trials were done with Valmet’s Optifilter CR250/2 and various membranes. First, results were gathered from five different membrane combinations in recycling, concentration and dilution stages. Then, a concentration trial was conducted and finally, laboratory results were made. The results were then compared.
The results show that P and RC membranes compared to P10 and P20 membranes give similar laboratory results. The concentration trials show that there are differences between these membranes in permeate flux rates. P10 and P20 membranes are tighter compared to P and RC membranes and therefore the differences are explained. It takes more time to filtrate with P10 and P20 membranes, which can affect the expenses in the used processes. The yield in lignin slurry is higher in the concentrate, but in the permeate fluxes the dry solids are reduced.
In conclusion, both mentioned membrane combinations give similar results and there is no big difference to be seen. Ultrafiltration has many advantages and it is preferred to be used in HTC process as well. These results, however, need more studying to confirm what combination works the best. More stable conditions should also be created in order to achieve more reliable results. Temperature can be controlled, which would have an effect on the overall results. The particle sizes of the permeate fluxes after filtrating with different membranes would have been interesting to see. These can be predicted from the membranes pore size, but the shape of the particle cannot be seen. Altogether, the both aims of the study were fulfilled and the behaviors of the membranes are compared and discussed.