The chemical transport model PMCAMx was extended to investigate the eddects of partitioning and photochemical aging of primary biomass burning emissins on organic aerosol (OA) concentrations. A source-resolved version of the model was developed, PMCAMx-SR, in which biomass burning OA (bbOA) and its oxidation products are represented seperately from the other OA sources. The volatility distribution of bbOA was simulates using recent measurements. According to PMCAMx-SR, during the early summer period simulated, the contribution of bb emissions to total OA levels is approximately 4%. During winter the same contribution is nearly 28% due to both extensive residential wood combustion and wildfires in Portugal and Spain. The magnitude of these impacts also depends on the emissions of intermediate volatility organic compounds during biomass burning. In order to evaluate PMCAMx-SR performance, its predictions were compared with aerosol mass spectrometer measurements that took place in several sites around Europe. The new version of the model does have improved performance over the original PMCAMx in most sites. / Το μοντέλο χημικής μεταφοράς PMCAMx επεκτάθηκε ώστε να μελετήσουμε την επίδραση της φωτοχημικής γήρανσης των εκπομπών από καύση βιομάζας στην συγκέντρωση του οργανικού αεροζόλ (ΟΑ). Μια νέα έκδοση του μοντέλου αναπτύχθηκε, PMCAMx-SR, στην οποία το οργανικό αεροζόλ από καύση βιομάζας και τα προιόντα οξείδωσης του παρουσιάζονται ξεχωριστά από τις υπόλοιπες πηγές ΟΑ. Η κατανομή πτητικότητας του οργανικού αεροζόλ από καύση βιομάζας προσομοιώνεται χρησιμοποιώντας πρόσφατες μετρήσεις. Σύμφωνα με το PMCAMx-SR, κατά την καλοκαιρινή περίοδο προσομοίωσης, η συνεισφορά των εκπομπών από καύση βιομάζας στα συνολικά επίπεδα ΟΑ είναι περίπου 4%. Κατά την διάρκεια του χειμώνα η ίδια συνεισφορά είναι περίπου 28% εξαιτίας εκτεταμένης οικιακής καύσης ξύλου και πυρκαγιών στην Πορτογαλία και την Ισπανία. Σημαντικός είναι και ο ρόλος των εκπομπών οργανικών σωματιδίων ενδιάμεσης πτητικότητας από καύση βιομάζας. Για να αξιολογήσουμε το PMCAMx-SR, οι προβλέψεις του συγκρίθηκαν με τις μετρήσεις ΑΜS που έλαβαν χώρα σε αρκετά μέρη στην Ευρώπη. Η νέα έκδοση του μοντέλου έχει βελτιώσει την απόδοση του αρχικού μοντέλου PMCAMx σε αρκετά μέρη ανά την Ευρώπη.

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The research presented focuses on the use of Carbon-dioxide (CO₂), Nitrogen (N₂) and Argon (Ar) as purge gases for torrefaction. Torrefaction using CO₂ as a purge gas may further improve the fuel characteristics of the torrefied fuel when compared to N₂ and Ar (which are entirely inert), making it better suited for use as a fuel for co-firing with coal or gasification. Three different biomasses were investigated: Juniper wood chips, Mesquite wood chips, and forage Sorghum. Experiments were conducted using a thermo-gravimetric analyzer (TGA, TA Instruments Model Q-600) to determine the effect of the purge gas over a wide range of torrefaction temperatures (200-300°C). TGA weight traces (thermograms) showed an increased mass loss when using CO2 as a purge gas when compared to N₂. The increased mass loss when CO₂ was used is attributed to a hypothesized reaction between the CO₂ and fixed Carbon contained within the biomass. Torrefaction of biomass, using Ar as the purge gas, produced results similar to torrefaction using N₂. Derivative Thermo-Gravimetric analysis (DTG) was done to determine the temperature ranges over which the three main components of biomass (hemicellulose, cellulose, and lignin) decomposed. The DTG results are in agreement with previously published research. From TGA thermograms and DTG analysis it was determined that torrefaction at higher temperatures (>260°C) likely result in the breakdown of cellulose during torrefaction, an undesired outcome. Proximate, ultimate, and heat value analysis was done on all three biomasses. All three contain a relatively high Oxygen content, which serves to decrease the higher heating value (HHV) of the biomass. The HHV of Juniper, Mesquite, and Sorghum on a dry ash-free (DAF) basis were 20,584 kJ/kg, 20,128 kJ/kg, and 19,389 kJ/kg respectively. The HHV of the three biomasses were relatively constant as expected for agricultural biomass. From TGA analysis (thermograms and DTG), an optimal torrefaction temperature was determined (240°C) based upon the amount of mass lost during torrefaction and estimates of energy retained. Batch torrefaction of all three biomasses at the optimal torrefaction temperature was completed using a laboratory oven. All three biomasses were torrefied using CO₂, N₂, and Ar as a purge gas. Proximate, ultimate, and heat value analysis was done for each of the torrefied fuels and compared. Results of the fuel property analysis showed torrefaction reduced the moisture content and oxygen percentage of the fuel resulting in the torrefied biomass having a larger HHV when compared to raw biomass. Due to inherent mass lost during torrefaction, the amount of energy retained in the torrefied biomass was calculated to determine the percentage of the virgin biomass energy content that remained. Torrefaction using CO2 resulted in the lowest amount of energy retention of all three purge gases tested (78.86% for Juniper); conversely, Nitrogen resulted in the highest amount of energy retention (91.81% for Sorghum.) Torrefaction of the biomass also increased the fixed carbon (FC) content of the fuel. The grindability of the torrefied biomass was investigated via size distribution analysis of the raw and ground biomass. Initial size distribution analysis showed that torrefaction of Mesquite and Juniper resulted in smaller particle sizes; with a greater fraction of the torrefied biomass passing through smaller meshes. Analysis of the ground biomass samples showed that torrefaction improved the grindability of the fuel. The percent of torrefied biomass that passed through an 840 micrometer mesh increased by over 20% for both Mesquite and Juniper when ground. Sorghum exhibited similar increases; however, the amount of increase is less apparent due to the smaller particle size distribution of the raw Sorghum.

Comprehensive analyses are conducted of the holistic farm production-harvesting-transporting-pre-refinery storage supply chain paradigm which represents the totality of important issues affecting the conversion facility front-gate costs of delivered biomass feedstocks. Targeting the Middle Gulf Coast, Edna-Ganado, Texas area, mathematical programming in the form of a cost-minimization linear programming model(Sorghasaurus) is used to assess the financial and economic logistics costs for supplying a hypothetical 30-million gallon conversion facility with high-energy sorghum (HES) and switchgrass (SG) cellulosic biomass feedstock for a 12-month period on a sustainable basis. A corporate biomass feedstock farming entity business organization structure is assumed. Because SG acreage was constrained in the analysis, both HES and SG are in the optimal baseline solution, with the logistics supply chain costs (to the front gate of the conversion facility) totaling $53.60 million on 36,845 acres of HES and 37,225 acres of SG (total farm acreage is 187,760 acres, including HES rotation acres), i.e., $723.67 per harvested acre, $1.7867 per gallon of biofuel produced not including any conversion costs, and $134.01 per dry ton of the requisite 400,000 tons of biomass feedstock. Several sensitivity scenario analyses were conducted, revealing a potential range in these estimates of $84.75-$261.52 per dry ton of biomass feedstock and $1.1300-$3.4870 per gallon of biofuel. These results are predicated on simultaneous consideration of capital and operating costs, trafficable days, timing of operations, machinery and labor constraints, and seasonal harvested biomass feedstock yield relationships. The enhanced accuracy of a comprehensive, detailed analysis as opposed to simplistic approach of extrapolating from crop enterprise budgets are demonstrated. It appears, with the current state of technology, it is uneconomical to produce cellulosic biomass feedstocks in the Middle Gulf Coast, Edna-Ganado, Texas area. That is, the costs estimated in this research for delivering biomass feedstocks to the frontgate of a cellulosic facility are much higher than the $35 per ton the Department of Energy suggests is needed. The several sensitivity scenarios evaluated in this thesis research provides insights in regards to needed degrees of advancements required to enhance the potential economic competitiveness of biomass feedstock logistics in this area.

Biomass gasification is a technology under development that presents a means of generating hydrogen using renewable energy. While many forms of gasification have been investigated, steam gasification using a dual fluidised bed (DFB) reactor has been shown to efficiently produce high hydrogen content producer gas. The aims of this research were to increase the hydrogen yield from the 100kW DFB gasifier installed at the University of Canterbury, and thereby improve the current state of the art of gasifier operation. Calcium carbonate-based minerals such as calcite and dolomite were shown to be able to improve hydrogen production by absorbing carbon dioxide in the producer gas, promoting the water gas shift reaction. Bed material mixtures of olivine and calcite were the most effective at improving gasifier performance, increasing producer gas yield by 20%, increasing cold gas efficiency by 6% and increasing hydrogen yield by 85%. In addition, the carbon monoxide content was reduced and the ratio of hydrogen to carbon monoxide in the producer gas was ideal for Fisher-Tropsch synthesis of liquid fuels.

The importance of microbial biomass of low concentration, regular additions of soluble organic substrate to carbon-limited soils, such as might occur with throughfall, has been studied. The conclusions depended upon the method used to measure C concentrations. Using a TOCsin automated analyser, the high level treatment enhanced biomass C, whereas the lower level treatment had small and variable effects, but using dichromate oxidation led to the conclusion that the low level treatment had a negative effect, and even the high level treatment had no beneficial effect. A further evaluation showed that the TOCsin procedure gave low recoveries of biomass C for bacterial monoculture suspension, an effect attributed to transport-related phenomena, and could not cope with continuous SO₄^2- inputs. However, use of Cl^- to extract C before and after fumigation altered the amount of C obtained. Therefore dichromate oxidation was used subsequently. The changes in microbial biomass, ATP concentration and respired CO₂ for glucose-amended soil have been measured over 9 days, and the dynamic responses shown to differ. The large changes in ATP-to-biomass C ratio show that ATP should not be used as a surrogate for biomass C determination after fresh substrate addition. Subsequently, ¹⁴C-labelled pea plant residues have been used to study differences in response of the three determinants to incorporation of water-soluble (WS), water-insoluble (WI), and unwashed (UW) plant residue materials. For plant materials too, ATP-to-biomass C ratios changed in response to substrate additions, increasing substantially (as for glucose) for WS additions, but decreasing after W1 residue incorporation. In the shorter term, higher biomass C was favoured more by incorporation of WI than of WS plant residues.

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This thesis examined the conversions of biomass and biomass components to petrochemicals and total aliphatic gasoline like products. There are three major projects of the thesis. Since biomass is very complicated, to understand the thermal decomposition pathways of biomass, the pyrolytic behaviors of various biomass components including lignin and cellulose under different reaction were investigated in the first phase. Due to complexity and limited volatility, the thermal decomposition products from biomass bring insurmountable obstacles to the traditional analysis methods such as GC-MS, UV and FT-IR. Therefore, precise characterization of the whole portion of thermal decomposition products has significant impacts on providing insight into the pyrolysis pathways and evaluating the upgrading processes. Various NMR methods to characterize different functional groups presented in liquid and solid pyrolysis products by 1H, 13C, 31P, 2D-HSQC and solid state 13C-NMR were introduced in the second phase. Nevertheless, the major drawback towards commercialization of pyrolysis oils are their challenging properties including poor volatility, high oxygen content, molecular weight, acidity and viscosity, corrosiveness and cold flow problems. In situ upgrading the properties of pyrolysis oils during thermal conversion process by employing zeolites has been discussed in the third phase. The further hydrogenation of pyrolysis oils to total aliphatic gasoline like products by heterogeneous catalysis in “green medium” – water has also been examined in the third project.

5-HMF as a versatile organic compound is considered as a promising biomass-derived value-added product via dehydration of saccharide. A large amount of research has been carried out on its production and separation. In this research, three single and three mixed solvents were tested to separate 5-HMF via liquid-liquid extraction from simulated HTC products. The mixed solvents were made up of DCM-THF, DCM-2-butanol and 2-butanol-THF with different mixing ratio of 1:4, 1:1, and 4:1. 20wt% and 10wt% NaCl were added in to help phase separation and to improve the performance of extraction. The simulated HTC product was composed of 5-HMF, levulinic acid and furfural. The extraction was carried out in vial and the phase separation was accomplished in a separatory funnel. The aqueous phase was analyzed with HPLC-UV to determine the solute concentrations in the aqueous phase. The solute concentrations in organic phase, partition coefficients, separation factors, solute recovery rates and purities of 5-HMF in separated products were calculated accordingly. The separation performance of mixed solvents was compared with theoretical values. In addition, the effects of pH and NaCl concentration on extraction and separation were investigated. It was found that the partition coefficients of 5-HMF were always higher than those of levulinic acid. 20 wt% of NaCl improved 5-HMF extraction significantly, and the corresponding partition coefficient was 6.87. Extraction of levulinic acid was found more sensitive to solvent pH value than 5-HMF and furfural. For 5-HMF extraction, pH 2.4 was more favorable than pH 2.0. Meanwhile, mixed solvents had better extraction performance than each single solvent for 5-HMF. The performance of the mixed solvents depended on mixing ratio; partition coefficient showed linear correlation with mixing fraction. More furfural was extracted into organic phase than 5-HMF, and the partition coefficients of levulinic acid were very close to that of 5-HMF. In general, however, mixed solvent extraction was able to improve the extraction efficiency rather than separation efficiency of 5-HMF.