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CO2 activation of char from Quercus agrifolia wood waste
07 Alternative energy sources (bioconversion energy) (Lespedeza cumeata (Dumont) G. Don. A summer growing perennial legume), were planted using two different strip widths (1.22 and 2.44 m) between trees on a 1.5 x 3 m spacing. The control had no competition. Height, ground-line diameter and volume index of trees were determined on a monthly basis. Lespedeza and tall fescue significantly reduced ground line diameter, height and volume index compared to ryegrass and the control. Crimson clover significantly reduced ground line diameter compared to the control and volume index more than ryegrass and the control. During Brst two growing seasons, there was no benefit from legumes as a cover crop over grasses. AI1 cover crops except rye grass significantly reduced sweetgum biomass compared to control. The results indicate that cover crops lespedeza, tall fescue, crimson clover and ryegrass reduced biomass by approximately 41% , 37%, 27% and lS%, respectively, compared to the control. The 2.44 m strip width reduced sweetgum growth 40% relative to the control vs. 20% with the 1.22 m strip width. Strip width had a greater impact on diameter and volume index than height.
Biomass steam gasification - an extensive parametric modeling study
02/01539
Schuster, G. et al. Bioresource Technology, 2001, 77, (I), 71-79. A model for steam gasification of biomass was developed by applying thermodynamic equilibrium calculations. With the model, the simulation of a decentralized combined heat and power station based on a dual fluidized-bed steam gasifier was carried out. Fuel composition (ultimate analysis and moisture content) and the operating parameters, temperature and amount of gasification agent, were varied over a wide range. Their influences on amount, composition, and heating value of product gas and process efficiencies were evaluated. It was shown that the accuracy of an equilibrium model for the gas composition is sufficient for thermodynamic considerations. Net electric efficiency of about 20% can be expected with a rather simple process. Sensitivity analysis showed that gasification temperature and fuel oxygen content were the most significant parameters determining the chemical efficiency of the gasification. 02lO1540 Changes in biogas reduction due to different ratios of some animal and agr Pcultural wastes Al-Masri, M.R. Bioresource Technology, 2001, 77, (I), 97-100. The biogas production and some biochemical parameters of anaerobic fermentation at 30°C for 40 days were studied for eight experimental groups of fermentation media, as affected by two factors: (1) the type of the animal waste (sheep waste, S and goat waste, G), and (2) the ratio of waste to olive cake which constitutes four levels (1OO:O for Sl and Gl; 80:20 for S2 and G2; 60:40 for S3 and G3 and 4060 for S4 and G4). The results indicated that there was a significant decrease (P < 0.05) in the biogas production with an increase in the proportion of olive cake in a place of animal waste. However, there was a significant increase in the biogas production for the S4 treatment compared with G4, reflecting an effect induced by the type of animal waste. The biogas production amounted to (l/kg VS/40 d): 62 (Sl), 53 (SZ), 49 (S3). 40 (S4), 58 (Gl), 50 (G2), 44 (G3) and 25 (G4). The reduction in total solid (TS) weight, volatile solids (VS), neutral-detergent tibre decreased significantly (P d 0.05) with the increase in olive cake proportion in the digester. The reductions in VS were (% in DM): 58.2 (Sl), 37.8 (S2). 26.6 (S3), 22.6 (S4), 58.1 (Gl), 36 (G2), 33.4 (G3), 14.4 (G4). The rates of energy consumption were (MJ/kg DM/40 d): IS.36 (Sl), 10.12 (S2), 7.84 (S3). 6.68 (S4), 14.16 (Gl), 9.68 (GZ), 8.41 (G3), 3.29 (G4).
Comparison of various types of acid hydrolysis reactors for alcohol fuel production
02/01541
Tsoutsos, T. D. and Koukios, E.G. 5th Conference on Applied Chemistry. Unit Operations and Processes. 405th Event of the European Federation of Chemical Engineering, 1989, 118-124. (In Hungarian) The carbohydrate hydrolysis can be carried out by contact with enzymes, or by pretreatment with mineral acids. Acid hydrolysis is a relatively rapid reaction, but requires high temperatures or high acid concentrations to achieve good yields. A two-stage acid hydrolysis process enables good yields. A two-stage acid hydrolysis process enables the hemicellulose and cellulose to be degraded separately under conditions appropriate for each reaction. High yields are obtained and mild conditions are required, with very little resultant degradation. In this paper a simulation form of typical hydrolysis reactors is presented which gives scope for optimizing the production and the fermentability of glucose. This study was undertaken to develop a group of models that would simulate a theoretical and a software basis for these reactors. 02lO1542
COs activation of char from Ouercus agrifdia
wood waste Sanchez, A.R. et al. Carbon, 2001, 39, (9), 1367-l 377. Three series of activated carbons were prepared from Quercus agrifolia wood using a two-step process, carbonization followed by physical activation with COs. Samples were characterized by Nz and CO2 adsorption. Three activation temperatures were used, 800, 840 and
880°C covering the 18-85 wt% yield range by variation of residence time. Activated carbons with a well-developed porous structure, predominantly microporous with high BET surface areas, were obtained. No direct relationship was found between exposed BET surface area (the surface where activation reaction takes place), evolution and gasification rate variation. Porosity development appears to be strongly influenced by the kinetic reaction stage, the reactant gas concentration gradient being an ultimate factor that induces porosity evolution.
Experimental and technico-economical evaluation of systems exploitin cellulosics to ethanol-to-ener y synthesis an 8 optimization of a sustainable tee Rnological system 02lO1543
Tsoutsos, T. PhD Thesis, National Technical University of Athens, Chemical Engineering Deparrmenf, 1990, (In Greek) The bioconversion of biomass to ethanol is a multi-stage process: collection, transportation, storing, saccharification, fermentation, separation ethanol/water, additional processes (pretreatments of lignocellulosics, hydrolysates) and byproduct (furfural, hydroxymethylfurfural) management. To face this complex subject successfully were developed methodological tools of three categories: computational, experimental and software. The cellulose hydrolysis is the ‘heart’ of the procedure. Based on the results in a batch reactor the model assessed was: cellulose -+ ki glucose + kz degradation products, where ki = Pi Ci”’ exp (-Ei/R(273 + 7)) (where Ci is the acid concentration and T the temperature). The results of this model were: El = 45 500 f40 kcal/ mole, Ez = 36 Ooo f 100 kcal/mole, ml = 0.70 f 0.08, iris= 0.68 f 0.09, pi = (1.78f0.06)~ lOI min-‘, Pz = (2.20+0.05) x 10 min-‘.
Impact of row spacing, nitrogen rate, and time on carbon partitioning of switchgrass
02iO1544
Ma, 2. er al. Biomass and Eioenergy, 2001, 20, (6) 413-419. Cultivation of switchgrass (Panicurn virgafum L.) as an energy crop could lower atmospheric carbon dioxide (CO*) levels by replacing fossil fuel and sequestering carbon (C). Information on the details of C partitioning within the switchgrass-soil system is important in order to quantify how much C is sequestered in switchgrass shoots, roots, and soil. No studies of C partitioning in a switchgrass-soil system under field conditions have been conducted. This study was aimed at determining the impact of agricultural management practices, such as row spacing and nitrogen (N) application rate, on C partitioning within the switchgrass-soil system; changes in C partitioning with time after switchgrass establishment were also considered. The results indicate that C storage in switchgrass shoots was higher with wide than narrow rows, and increased with N application rates. These responses were due to higher yields with wide than narrow rows and higher yields as N application rate increased. Carbon storage in shoots was 14.4% higher with 80tm than 20-cm row spacing. Annual application of 224 kg N ha-’ increased C storage in shoots by 207% and 27% when compared with annual applications of 0 and 112 kg N ha-.‘, respectively. Carbon storage increased by 62% over time from 1995 to 1996 in newly established switchgrass on sandy loam soil in the coastal plain of Alabama. Rate of C increase in roots (72%) was higher than in shoots (49%) between 1995 and 1996. Carbon storage was in order of soil C > root C > shoot C in both 1995 and 1996. The root/shoot ratio of C storage was 2.2. It appears that C partitioning to roots plays an important role in C sequestration by switchgrass. 02lO1545 Inhibitory effect of 5-hydrox methyfurfural on the alcoholic fermentation of glucose by syaacharomyces cefevisae Tsoutsos, T. D. et al. 6th European Conference on Biomass for Energy, Industry and Environmen/. Athens, 1991, 521-525. Large-scale production of bioethanol for energy purposes from cellulosic materials is critical in order to increase the efficiency of the alcoholic fermentation. The effect of the hydroxymethylfurfural (HMF) on rates of glucose fermentation to ethanol by Saccharomyces Cerevisae was studied. The batch experiments took place for different initial levels of HMF (0.8-0.8 g/litre) and glucose (So-100 g/litre). The effect of HMF concentration was simulated as function of initial glucose concentration, initial HMF concentration and time. A pseukinetic model was developed to simulate the HMF inhibition. The results and proposed models of the system’s behaviour are presented in this paper
Minimum fluidization velocities of mixtures of biomass and sands
02/01546
Rao, T.R. and Bheemarasetti, J.V.R. Energy, 2001, 26, (6), 633-644. The present work reports studies on the fluidization of mixtures of biomass and sands. The biomass materials used are rice husk, sawdust and groundnut shell powder, and the sands employed are of two different densities and particle sizes. Experiments are carried out in a 5 cm ID fluidized bed column to determine the minimum fluidization velocities. The percentage of biomass materials in the mixtures studied
Fuel and Energy Abstracts
May 2002
197
Biomass steam gasification - an extensive parametric modeling study
02/01539
Schuster, G. et al. Bioresource Technology, 2001, 77, (I), 71-79. A model for steam gasification of biomass was developed by applying thermodynamic equilibrium calculations. With the model, the simulation of a decentralized combined heat and power station based on a dual fluidized-bed steam gasifier was carried out. Fuel composition (ultimate analysis and moisture content) and the operating parameters, temperature and amount of gasification agent, were varied over a wide range. Their influences on amount, composition, and heating value of product gas and process efficiencies were evaluated. It was shown that the accuracy of an equilibrium model for the gas composition is sufficient for thermodynamic considerations. Net electric efficiency of about 20% can be expected with a rather simple process. Sensitivity analysis showed that gasification temperature and fuel oxygen content were the most significant parameters determining the chemical efficiency of the gasification. 02lO1540 Changes in biogas reduction due to different ratios of some animal and agr Pcultural wastes Al-Masri, M.R. Bioresource Technology, 2001, 77, (I), 97-100. The biogas production and some biochemical parameters of anaerobic fermentation at 30°C for 40 days were studied for eight experimental groups of fermentation media, as affected by two factors: (1) the type of the animal waste (sheep waste, S and goat waste, G), and (2) the ratio of waste to olive cake which constitutes four levels (1OO:O for Sl and Gl; 80:20 for S2 and G2; 60:40 for S3 and G3 and 4060 for S4 and G4). The results indicated that there was a significant decrease (P < 0.05) in the biogas production with an increase in the proportion of olive cake in a place of animal waste. However, there was a significant increase in the biogas production for the S4 treatment compared with G4, reflecting an effect induced by the type of animal waste. The biogas production amounted to (l/kg VS/40 d): 62 (Sl), 53 (SZ), 49 (S3). 40 (S4), 58 (Gl), 50 (G2), 44 (G3) and 25 (G4). The reduction in total solid (TS) weight, volatile solids (VS), neutral-detergent tibre decreased significantly (P d 0.05) with the increase in olive cake proportion in the digester. The reductions in VS were (% in DM): 58.2 (Sl), 37.8 (S2). 26.6 (S3), 22.6 (S4), 58.1 (Gl), 36 (G2), 33.4 (G3), 14.4 (G4). The rates of energy consumption were (MJ/kg DM/40 d): IS.36 (Sl), 10.12 (S2), 7.84 (S3). 6.68 (S4), 14.16 (Gl), 9.68 (GZ), 8.41 (G3), 3.29 (G4).
Comparison of various types of acid hydrolysis reactors for alcohol fuel production
02/01541
Tsoutsos, T. D. and Koukios, E.G. 5th Conference on Applied Chemistry. Unit Operations and Processes. 405th Event of the European Federation of Chemical Engineering, 1989, 118-124. (In Hungarian) The carbohydrate hydrolysis can be carried out by contact with enzymes, or by pretreatment with mineral acids. Acid hydrolysis is a relatively rapid reaction, but requires high temperatures or high acid concentrations to achieve good yields. A two-stage acid hydrolysis process enables good yields. A two-stage acid hydrolysis process enables the hemicellulose and cellulose to be degraded separately under conditions appropriate for each reaction. High yields are obtained and mild conditions are required, with very little resultant degradation. In this paper a simulation form of typical hydrolysis reactors is presented which gives scope for optimizing the production and the fermentability of glucose. This study was undertaken to develop a group of models that would simulate a theoretical and a software basis for these reactors. 02lO1542
COs activation of char from Ouercus agrifdia
wood waste Sanchez, A.R. et al. Carbon, 2001, 39, (9), 1367-l 377. Three series of activated carbons were prepared from Quercus agrifolia wood using a two-step process, carbonization followed by physical activation with COs. Samples were characterized by Nz and CO2 adsorption. Three activation temperatures were used, 800, 840 and
880°C covering the 18-85 wt% yield range by variation of residence time. Activated carbons with a well-developed porous structure, predominantly microporous with high BET surface areas, were obtained. No direct relationship was found between exposed BET surface area (the surface where activation reaction takes place), evolution and gasification rate variation. Porosity development appears to be strongly influenced by the kinetic reaction stage, the reactant gas concentration gradient being an ultimate factor that induces porosity evolution.
Experimental and technico-economical evaluation of systems exploitin cellulosics to ethanol-to-ener y synthesis an 8 optimization of a sustainable tee Rnological system 02lO1543
Tsoutsos, T. PhD Thesis, National Technical University of Athens, Chemical Engineering Deparrmenf, 1990, (In Greek) The bioconversion of biomass to ethanol is a multi-stage process: collection, transportation, storing, saccharification, fermentation, separation ethanol/water, additional processes (pretreatments of lignocellulosics, hydrolysates) and byproduct (furfural, hydroxymethylfurfural) management. To face this complex subject successfully were developed methodological tools of three categories: computational, experimental and software. The cellulose hydrolysis is the ‘heart’ of the procedure. Based on the results in a batch reactor the model assessed was: cellulose -+ ki glucose + kz degradation products, where ki = Pi Ci”’ exp (-Ei/R(273 + 7)) (where Ci is the acid concentration and T the temperature). The results of this model were: El = 45 500 f40 kcal/ mole, Ez = 36 Ooo f 100 kcal/mole, ml = 0.70 f 0.08, iris= 0.68 f 0.09, pi = (1.78f0.06)~ lOI min-‘, Pz = (2.20+0.05) x 10 min-‘.
Impact of row spacing, nitrogen rate, and time on carbon partitioning of switchgrass
02iO1544
Ma, 2. er al. Biomass and Eioenergy, 2001, 20, (6) 413-419. Cultivation of switchgrass (Panicurn virgafum L.) as an energy crop could lower atmospheric carbon dioxide (CO*) levels by replacing fossil fuel and sequestering carbon (C). Information on the details of C partitioning within the switchgrass-soil system is important in order to quantify how much C is sequestered in switchgrass shoots, roots, and soil. No studies of C partitioning in a switchgrass-soil system under field conditions have been conducted. This study was aimed at determining the impact of agricultural management practices, such as row spacing and nitrogen (N) application rate, on C partitioning within the switchgrass-soil system; changes in C partitioning with time after switchgrass establishment were also considered. The results indicate that C storage in switchgrass shoots was higher with wide than narrow rows, and increased with N application rates. These responses were due to higher yields with wide than narrow rows and higher yields as N application rate increased. Carbon storage in shoots was 14.4% higher with 80tm than 20-cm row spacing. Annual application of 224 kg N ha-’ increased C storage in shoots by 207% and 27% when compared with annual applications of 0 and 112 kg N ha-.‘, respectively. Carbon storage increased by 62% over time from 1995 to 1996 in newly established switchgrass on sandy loam soil in the coastal plain of Alabama. Rate of C increase in roots (72%) was higher than in shoots (49%) between 1995 and 1996. Carbon storage was in order of soil C > root C > shoot C in both 1995 and 1996. The root/shoot ratio of C storage was 2.2. It appears that C partitioning to roots plays an important role in C sequestration by switchgrass. 02lO1545 Inhibitory effect of 5-hydrox methyfurfural on the alcoholic fermentation of glucose by syaacharomyces cefevisae Tsoutsos, T. D. et al. 6th European Conference on Biomass for Energy, Industry and Environmen/. Athens, 1991, 521-525. Large-scale production of bioethanol for energy purposes from cellulosic materials is critical in order to increase the efficiency of the alcoholic fermentation. The effect of the hydroxymethylfurfural (HMF) on rates of glucose fermentation to ethanol by Saccharomyces Cerevisae was studied. The batch experiments took place for different initial levels of HMF (0.8-0.8 g/litre) and glucose (So-100 g/litre). The effect of HMF concentration was simulated as function of initial glucose concentration, initial HMF concentration and time. A pseukinetic model was developed to simulate the HMF inhibition. The results and proposed models of the system’s behaviour are presented in this paper
Minimum fluidization velocities of mixtures of biomass and sands
02/01546
Rao, T.R. and Bheemarasetti, J.V.R. Energy, 2001, 26, (6), 633-644. The present work reports studies on the fluidization of mixtures of biomass and sands. The biomass materials used are rice husk, sawdust and groundnut shell powder, and the sands employed are of two different densities and particle sizes. Experiments are carried out in a 5 cm ID fluidized bed column to determine the minimum fluidization velocities. The percentage of biomass materials in the mixtures studied
Fuel and Energy Abstracts
May 2002
197