Browsing by Author "Hurme, Markku, Prof."

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Industrial scale chromatographic separation of valuable compounds from biomass hydrolysates and side streams
(2011) Saari, Pia
Kemian tekniikan korkeakoulu | Doctoral dissertation (article-based)
Carbohydrates are composed of a number of various monosaccharides, glucose being the most abundant. Some of the monosaccharides are valuable compounds used in the food and pharmaceutical industries. They can be separated from biomass hydrolysates e.g. by chromatographic methods. In this thesis, chromatographic separation of valuable compounds using ion exchange resins was studied on an industrial scale. Of special interest were rare monosaccharides in biomass hydrolysates. A novel chromatographic separation process was developed for fucose, starting from pre-processed spent sulfite liquor. The core of the process consists of three chromatographic separations with different types of ion exchange resins. Chromatographic separation of galactose was tested with three biomass hydrolysates; lactose, gum arabic and hemicellulose hydrolysates. It was demonstrated that also galactose can be separated from complex carbohydrate mixtures. A recovery process for arabinose from citrus pectin liquid residual and for mannose from wood pulp hydrolysate were also developed and experimentally verified. In addition to monosaccharides, chromatographic separation of glycinebetaine from vinasse was examined with a hydrogen form weak acid cation exchange resin. The separation involves untypical peak formation depending, for example, on the pH and the cation composition. The retention mechanism was found to be hydrogen bonding between glycinebetaine and the resin. In the experimental part, all four resin types - strong acid cation, strong base anion, weak acid cation and weak base anion exchange resins - were used. In addition, adsorption equilibria data of seven monosaccharides and sucrose were measured with the resins in sodium and sulfate forms because such data have been lacking. It was found out that the isotherms of all sugars were linear under industrial conditions. A systematic method for conceptual process design and sequencing of chromatographic separation steps were developed. Heuristics were drawn from the current industrial practices also for the selection of a suitable ion exchange resin for the separation of a sugar from a biomass hydrolysate.
Inherent occupational health assessment in chemical process development and design
(2010) Hassim, Mimi Haryani
Aalto-yliopiston teknillinen korkeakoulu | Doctoral dissertation (article-based)
Sustainability is now a necessity to process industry. Therefore the safety, health, and environmental (SHE) evaluations are required in process design and operation. Various methods for assessing safety and environmental friendliness have been presented in literature. However, occupational health evaluations have received much less attention even though each year more people die from work-related diseases than are killed in industrial accidents. Inherent occupational health assessment is an approach to reduce hazards by choosing healthier chemicals and process concepts. I.e. inherent occupational health relies on the healthier and safer properties of chemical substances, process conditions, operations, and work procedures in a process. This thesis presents new systematic approaches for evaluating inherent occupational health of chemical processes in process development and design. In the R&D stage, the Inherent Occupational Health Index (IOHI) is proposed based on healthier and safer reaction chemistries, properties of compounds present, and process conditions such as pressure, volatility, exposure limits, and temperature etc. In the preliminary design stage, chronic health risk is calculated due to exposure to fugitive airborne emissions based on flow sheet data and precalculated process modules' emission, estimated process plot areas, and wind velocities. Health Quotient Index (HQI) is used as a health indicator to compare the estimated chemical concentrations to their exposure limits. In the basic engineering stage, the Occupational Health Index (OHI) utilizes detailed fugitive emission calculations based on piping and instrumentation diagrams. The method evaluates quantitatively chronic inhalation risks to noncarcinogens and carcinogens, acute inhalation risk, and qualitatively dermal/eye risk. For fugitive exposure estimation new methods were developed. Three approaches for estimating chemical concentration due to fugitive emissions are proposed based on simple PFD, detailed PFD, and PID, which were tested on the actual Borealis Polymers plant in Porvoo. A more realistic approach was developed for estimating health risks of fugitive occupational exposure by using statistical meteorological data. Finally the integration of the inherent occupational assessment methods with the existing computer aided design tools was studied. Also the correlation between index-based SHE assessment techniques was analyzed to find out, if any interdependency exists between SHE characteristics at the inherent level.