Total Volatile Yield Research Articles

Comparison of acid and hydrothermal pretreatments of date waste for value creation

The production of date syrup yields a substantial amount of date press cake (DPC), fibrous and moisturising material with great potential for generating value through bioprocessing. However, the recalcitrant structure of DPC affects the yield of products in bioprocesses. To boost the accessibility of the structure as well as increase the soluble fraction of carbohydrates and facilitate further enzymatic hydrolysis, hydrothermal and dilute acid (0.5% (v/v) sulfuric acid) pretreatments as cost-effective and feasible methods were applied on DPC at relatively low temperatures (80, 100, 120 and 140 °C) and reaction times (60 and 90 min). The success in pretreatment was then evaluated by a post-enzymatic treatment using an enzyme cocktail of cellulases and hemicelluloses. Based on total accessible sugar with minimum produced inhibitors, an optimal operating condition was considered acid pretreatment at 120 °C for 90 min with a 55.02% increase in total sugar yield. To explore the potential use of pretreated DPC, an anaerobic digestion was conducted on untreated and acid-pretreated DPC at 120 °C for 90 min. The results showed that pretreatment increased the total bioproduct yield, including hydrogen, ethanol, and volatile fatty acid yields, by 59.75%. This demonstrates the significant impact of pretreatment on product yields in a bioprocess.

A Glycosyl Hydrolase 30 Family Xylanase from the Rumen Metagenome and Its Effects on In Vitro Ruminal Fermentation of Wheat Straw.

The challenge of wheat straw as a ruminant feed is its low ruminal digestibility. This study investigated the impact of a xylanase called RuXyn, derived from the rumen metagenome of beef cattle, on the in vitro ruminal fermentation of wheat straw. RuXyn encoded 505 amino acids and was categorized within subfamily 8 of the glycosyl hydrolase 30 family. RuXyn was heterologously expressed in Escherichia coli and displayed its highest level of activity at pH 6.0 and 40 °C. RuXyn primarily hydrolyzed xylan, while it did not show any noticeable activity towards other substrates, including carboxymethylcellulose and Avicel. At concentrations of 5 mM, Mn2+ and dithiothreitol significantly enhanced RuXyn's activity by 73% and 20%, respectively. RuXyn's activity was almost or completely inactivated in the presence of Cu2+, even at low concentrations. The main hydrolysis products of corncob xylan by RuXyn were xylopentose, xylotriose, and xylotetraose. RuXyn hydrolyzed wheat straw and rice straw more effectively than it did other agricultural by-products. A remarkable synergistic effect was observed between RuXyn and a cellulase cocktail on wheat straw hydrolysis. Supplementation with RuXyn increased dry matter digestibility; acetate, propionate, valerate, and total volatile fatty acid yields; NH3-N concentration, and total bacterial number during in vitro fermentation of wheat straw relative to the control. RuXyn's inactivity at 60 °C and 70 °C was remedied by mutating proline 151 to phenylalanine and aspartic acid 204 to leucine, boosting activity to 20.3% and 21.8% of the maximum activity at the respective temperatures. As an exogenous enzyme preparation, RuXyn exhibits considerable potential to improve ruminal digestion and the utilization of wheat straw in ruminants. As far as we know, this is the first study on a GH30 xylanase promoting the ruminal fermentation of agricultural straws. The findings demonstrate that the utilization of RuXyn can significantly enhance the ruminal digestibility of wheat straw by approximately 10 percentage points. This outcome signifies the emergence of a novel and highly efficient enzyme preparation that holds promise for the effective utilization of wheat straw, a by-product of crop production, in ruminants.

High pressure CO2 gasification of Morupule coal: Kinetics and morphological development of chars

A direct gasification approach, coupling pyrolysis and gasification, was employed to study the kinetics of Morupule coal gasification in CO2 using a wire-mesh reactor (WMR) at elevated pressures (up to 20 bara) and temperatures of 900 °C and 1000 °C. A novel non-destructive analytical technique based on X-Ray computed tomography (CT) was used, for the first time, in conjunction with scanning electron microscopy (SEM) to unravel the morphological evolution of pyrolysis and gasification chars produced from the WMR. Lower total volatile yields were obtained at high pressures compared to atmospheric pressure for 0 s (quenching the reaction upon reaching temperature) holding time experiments. A temperature dependence of the gasification reaction rate at elevated pressures was observed. At 900 °C, increasing the pressure beyond 10 bara did not yield a commensurate increase in the reaction rate. Further increases in pressure to 20 bara at 1000 °C led to a pronounced increase in the reaction rate. The applicability of the Langmuir – Hinshelwood (L – H) rate model was investigated and showed a suitable characterisation of the gasification kinetics driven by a CO2 chemisorption-limited reaction mechanism. X-Ray CT imagery reveal the development of an internal macroporosity produced by the explosive release of volatiles during pyrolysis. In contrast, SEM images indicate that high pressure coal gasification is characterised by the development of micropores, with a rapid consumption of the outer char surface.

Fresh cassava root replacing cassava chip could enhance milk production of lactating dairy cows fed diets based on high sulfur-containing pellet

The experiment objective was to assess the shifting effect from cassava chip (CC) to fresh cassava root (FC) affected feed utilization, rumen metabolism, cyanide-using bacteria, and milk quality in lactating Thai Friesian dairy cows fed diets based on high sulfur-containing pellet (PS). Four lactating Thai Friesian dairy cows of 481.5 ± 31.3 kg BW (about 4 years old were allocated with four treatments in a 4 × 4 Latin square design. The four treatments were: replacement FC for CC at 0%, 60%, 80%, and 100% dry matter (DM), respectively. Feed intakes for four diets in terms of total dry matter intake (kg/day and % BW) was linearly correlated with levels of replacement of FC (p < 0.01). Digestibilities of crude protein (CP), DM, organic matter (OM), amylase-treated neutral detergent fiber (aNDF), and acid detergent fiber (ADF) did not change with increasing levels of FC in the diet (p > 0.05). Moreover, the total bacterial counts and cyanide population utilizing bacteria cubically increased with an increase of FC replacement (p < 0.01). The effect of CC substitution with FC in the PS diet was cubically increased on blood thiocyanate concentrations (p < 0.01). In addition, the propionate (C3) concentration at 0 and 4 h post-feeding changed significantly among treatments (p < 0.01), which were linearly improved with an increasing dose of replacement FC and were highest when FC was replaced at 100%. The yield of 3.5% fat-corrected milk was high in the treatment with the replacement of FC as compared to the control (p < 0.01). The yield of fat and milk fat percentages was high (p < 0.01) in the group with the replacement of FC as compared to feed with no diet replaced. The milk thiocyanate concentration was cubically enhanced when levels of FC replacement increased (p < 0.01) and was the highest when FC was replaced at 100%. As the amount of FC replacement was raised, the somatic cell count in the milk decreased linearly (p < 0.01). In conclusion, the replacement of FC at 100% in PS could enhance the feed intake, microbial populations, total volatile fatty acid (VFA), C3 concentration, milk yield, and milk quality.

Measurement and Importance of Volatile Matter in Coals and Biofuels

Abstract Volatile matter values for solid fuels are used to assess their burning rates and, thus, provide a basis for the buying and selling of these fuels. The major factors that affect volatile matter yields are the type of fuel, moisture contents, and the heating rates used in the tests. This paper reports the results of experiments designed to improve the reliability and application of test methods for the determination of volatile matter in various solid fuels. The macro thermogravimetric analysis studies described herein include the rapid drying of analysis samples of coal and the effect on volatile matter yields, the heating of various chars at high temperatures to reach a state of constancy, the measuring of decomposition moisture, an “elusive” constituent in coal, and the cocombustion of coals and other solid fuels. The presence of residual moisture and decomposition moisture in the coal during the volatile matter tests increases the measured volatile matter yields even though the residual moisture has been factored out. The rates of heating solid fuels during volatile matter tests affect the volatile matter yields because of the presence of different types of moisture in the fuel that are released at different temperatures. The heating rates used in volatile matter tests affect the type of compounds released and the total volatile matter yields of coals and biofuels. The experiments reported in this paper were instrumental in the decision of ASTM Committee D05 on Coal and Coke to recently revise the classic volatile matter standard test method D3175 to change the temperature for drying sparking coals from 600°C to 107°C. The role volatile matter plays in the combustion of fuel blends is discussed in this article.

Morphology of char particles from coal pyrolysis in a pressurized entrained flow reactor: Effects of pressure and atmosphere

A pressurized drop tube furnace was used to study the pyrolysis behavior of bituminous and lignite coal at elevated pressure. Experiments were conducted at the pressure range from 1 to 10 atm in 100% N2 or 100% CO2 atmosphere. The volatile yields, char morphology, swelling ratio, and pore structure were discussed in detail. The results show that the pressure, atmosphere and coal rank could effect on the volatile releasing and char evolution significantly. In N2 atmosphere, the total volatile yields of YL and NM coal decrease as the pressure elevated, while in CO2 atmosphere, the mass release of NM coal increases at high pressure contributed by the reaction of CO2 with organic macromolecule inside the particles; different with bituminous coal, no significant swelling behavior is found with the increase of pressure; the BET surface area of YL char decreases as the pressure increases, while for lignite coal, in N2 atmosphere and at high pressure, less macro pores are formed, which could contribute to the BET surface area. While in CO2 atmosphere, the CO2-macromocular organic reaction would promote the volatile releasing, and the BET surface area decreases significantly at high pressure.

Hydrothermal vs. dilute acid pre-treatments: comparison of the biomass properties, distribution of pyrolysis products, and bio-oil characteristics

In this study, hydrothermal and acid pre-treatments were applied to improve the raw material properties of the bean pod. To evaluate the biomass as a fuel, it is superior to have low moisture content, high volatile matter, and carbon content. As acid concentration changed in acid washing and impregnation, different trends were observed in these contents. The optimum working concentration to meet all these properties was chosen as 1 M acid. In hydrothermal pre-treatment, as the temperature increased with constant reaction time, the moisture content of the biomass decreased while the amount of volatile matter was raised. According to the SEM, FT-IR, TGA, and preliminary and elemental analysis characterization results, the samples with high C and low O content after evaluating in hydrothermal pre-treatment at 190 °C for 20 min and hydrothermal pre-treatment at 150 °C for 20 min, washing with 1 M H3PO4, and impregnating with 1 M H3PO4 were subjected to pyrolysis process. When the tar yields obtained from impregnating with 1 M H3PO4 and washing with 1 M H3PO4 samples were compared, it was seen that the washing process gave a higher (19.56%) tar yield. In the pyrolysis experiments, the highest tar yield (22.18%) was achieved by using the hydrothermal pre-treatment at 190 °C for 20 min sample with a volatile matter content of 71.59%. Total volatile matter yields of pyrolysis were listed as (hydrothermal pre-treatment at 190 °C for 20 min) > (washing with 1 M H3PO4) > (impregnating with 1 M H3PO4) > (hydrothermal pre-treatment at 150 °C for 20 min). As a result, it can be concluded that the processes performed as hydrothermal method or acidic pre-treatment compared to raw biomass have an important role in obtaining the desired product distribution and properties in biofuel production.

Chemical Composition and Antibacterial Activity of Orange (Citrus sinensis) Essential Oils Obtained by Hydrodistillation and Solvent free Microwave Extraction

Essential oils (EOs) have gained much media attention in recent years because of their advantages in various fields, including food preservation, pharmaceuticals, herbal medicine, and natural therapies. Phenolic components which exhibit antimicrobial activity, along with some healthy substances, are present abundantly in essential oils, hence their use to prevent bacterial growth. Oranges are amongst the world’s most popular fruits. Orange (Citrus sinensis) is widely recognized for its nutritious and medicinal properties. Since time immemorial, most parts of the orange plant from fruits, peels, flowers, leaves and juice are used as traditional medicine. Hydrodistillation (HD) and solvent free microwave extraction (SFME) were used to extract essential oils from orange fruit peels. The total volatile compound yield is obtained from 98-100% by HD and SFME. Gas chromatography-mass spectrometry (GC-MS) analysis revealed that the oils obtained from both method contained limonene (98.238% and 98.415, β-myrcene (1.169% and 1.172%) and α-pinene (0.548% and 0.413%). A small amount of sabinene (0.071%) and β- pinene (0.0032%) were only found in SFME-produced orange essential oil. The essential oils obtained from the two extraction methods were able to inhibit against Bacillus cereus.

Linking char reactivity to structural and morphological evolution during high pressure pyrolysis of Morupule coal

Understanding the influence of pressure on char physicochemical properties and reactivity during pyrolysis is principal for the design and optimisation of coal gasification technologies. This work investigated the pyrolysis behaviour of Morupule coal at various pressures and temperatures in a high-pressure wire-mesh reactor (HPWMR). The effect of pressure was pronounced at 600 and 800 °C, resulting in lower total volatile yields at higher pressures due to the repolymerisation of volatiles. Although graphitisation was limited during the heating period, an increase in the concentration of ordered structures was observed during holding at 1000 °C. Marked blowholes on the char surface suggested an explosive bubble transport phenomenon during pyrolysis. Chars produced during the ramping period under high pressure showed higher combustion reactivities than their low-pressure counterparts. However, prolonged holding at peak temperature produced chars of similar reactivity, with their CO2 gasification reactivity found to be independent of pyrolysis pressure.

Anaerobic co-digestion of swine manure with sweet potato or cassava in different C/N ratios

ABSTRACT: Anaerobic co-digestion (AcoD) of waste is a method of increasing methane (CH4) yield and improving biofertilizer quality. This study aimed to evaluate the best AcoD conditions for swine manure (SM) with sweet potato (SP) or cassava (C) in different amounts in semi-continuous biodigesters. Initially, using batch biodigesters, an AcoD test of the SM with SP or C was performed, adopting carbon/nitrogen (C/N) ratios of 10/1, 13/1, 17/1, and 22/1. Based on the results, a C/N ratio of 10/1 was chosen, which was the proportion that resulted in the highest reduction of volatile solids (VS) and specific biogas production. From these results, the experiment was carried out in semi-continuous biodigesters, consisting of three treatments (control (SM), SP 10/1, and C 10/1) with five replicates and a hydraulic retention time (HRT) of 30 days. Total solid (TS) and volatile solid (VS) reductions, biogas and CH4 yields, alkalinity, and volatile acidity were measured. The control treatment differed from the others and resulted in decreased biogas yield (752 LN.kgVSadded -1), CH4 (449 LN.kgVSadded -1), and CH4 content (59.7%). The AcoD treatments (SP and C) did not differ significantly for biogas yield (respectively, 901 and 883 LN.kgVSadded -1) and CH4 (respectively, 590 and 547 LN.kgVSadded -1); however, they differed in CH4 content (65.5% and 61.9% respectively). The treatments showed general reduction averages of 76.1% and 85.9% for TS and VS, respectively, with no statistical difference found between them. The AcoD of the SM with SP or C increased the production and quality of the biogas, increasing the concentration of CH4 therein.

Modeling devolatalization process of Serbian lignites using chemical percolation devolatilization model

Different mathematical models can describe coal devolatilization as the part of combustion process. Some models are simple, while others are more complex and take into account coal's complexity and heterogeneity of structure. A chemical percolation devolatilization model for describing the devolatilization process of two Serbian lignites from Kostolac and Kolubara open coal mines was studied. Results of the model were compared to devolatilization measurements obtained from two experimental methods ? a wire mesh reactor and thermogravimetric analysis. Two coal samples with four different granulations were investigated for each lignite under different experimental conditions (different maximum temperatures and heating rates). Total volatile yields obtained from the wire mesh reactor and thermogravimetric analysis together with results predicted by the chemical percolation devolatilization model are presented and compared with literature data. For thermogravimetric analysis simulation, the chemical percolation devolatilization model yielded better results in cases where the kinetic parameters obtained under experimental conditions were used rather than kinetic parameters derived from predefined values in the model itself. For wire mesh reactor, the chemical percolation devolatilization model predictions of devolatilization were mixed and were dependent on temperature.

Upgrading Physicochemical Properties using Torrefaction Process and Anhydrous Weight Loss Modelling for Palm Mesocarp Fiber

Abstract Torrefaction is a thermal process for upgrading biomass properties in order to promote biomass utilization for sustainable energy production. It is performed under inert condition at temperature range 200 - 300°C with residence times between 15 – 60 minutes. Torrefied product usually have high energy content, low moisture content and hygroscopic nature which overcome the limitation of raw biomass as biofuel. Therefore, the objective of this study is to investigate the characteristics of torrefied palm mesocarp fiber (PMF) and evolution of volatiles components during torrefaction at 240°C, 270°C, and 300°C in an inert condition. The condensable and non-condensable gases were analyzed using high performance liquid chromatography (HPLC) and gas chromatography mass spectrometry (GC-MS) respectively. Concurrently, a kinetic model using two reactions in series namely Di Blasi and Lanzetta model is developed to predict the evolution of solid and volatile products during torrefaction process for PMF samples. Based on torrefaction experiments, the mass and energy yields are decreased due to the severe decomposition of biomass at higher temperature but the higher heating value of biomass is increased by 27%. Meanwhile the proximate analysis shows that fixed carbon and ash content are increased by 45% and 25% respectively but volatile matter is decreased by 20%. In addition, the ultimate analysis shows that the elemental ratios of hydrogen to carbon (H/C) and oxygen to carbon (O/C) are decreased by 88% and 20% respectively. For the volatile analysis, 70 – 80% of the total volatile yield is made up from non-condensable gases with high percentage of carbon monoxide (CO) and methane (CH4), while the condensable gases formed was 20-30%. Finally, the anhydrous weight loss model is successfully developed for representing the decomposition of PMF where the kinetic parameters estimated from the model give a good agreement with the residual mass obtained from thermogravimetric analysis.

Chemical Composition of the Essential Oil, Total Phenolic Content and Antioxidant Activity of Vitex pseudo-negundo Seeds Collected from Northeastern Iran

In this study, the essential oil obtained by hydrodistillation of the seeds of Vitex pseudo-negundo (Verbenaceae), growing wild in Sabzevar, Khorasan Razavi Province, Iran, were analyzed by GC and GC/MS. The yield of total volatiles was 0.8% (w/w). Thirty-seven compounds representing 92.4% of the seed oil were identified. The main components of the oil were hexadecanoic acid (8.0%), elemol (7.0%) and α-bisabolol (6.1%). The oil was rich in sesquiterpene hydrocarbons (51.2%). The total flavonoids of different extracts of the plant were found the range 56-195 mg/g, with the maximum amount being in the methanol extract. In addition, the antioxidant activities of the extracts were measured by radical scavenging activity of antioxidants against the free radical 1, 1-diphenyl-2-picrylhydrazyl (DPPH). The antioxidant activities of the extracts of V. pseudo-negundo seed were higher than those of the standard synthetic antioxidants, BHT, ascorbic acid and gallic acid.

Specific Features of Solid Fuels Combustion in Oxygen Atmosphere with Recirculation of CO2

&lt;p&gt;Aspects of coal combustion have been experimentally studied under oxyfuel conditions, one of the promising technologies for carbon capture and storage (CCS). Here, the thermogravimetric analysis (TGA) method was chosen as an experimental technique. Coal pyrolysis tests performed under an O&lt;sub&gt;2&lt;/sub&gt;/CO&lt;sub&gt;2&lt;/sub&gt; atmosphere were compared with a conventional O&lt;sub&gt;2&lt;/sub&gt;/N&lt;sub&gt;2&lt;/sub&gt; environment in terms of reaction rate and total volatile yield. Combustion of the resulting chars in the corresponding atmospheres revealed somewhat different combustion rates with a less vigorous reaction in the O&lt;sub&gt;2&lt;/sub&gt;/CO&lt;sub&gt;2&lt;/sub&gt; medium. The two manipulated factors – namely, the inherently different char reactivities due to the different atmospheres they were obtained in and the different atmospheres of the actual combustion process – were distinguished by performing another series of tests with chars pyrolysed under identical conditions using a standard routine. These chars also showed a weaker reaction in O&lt;sub&gt;2&lt;/sub&gt;/CO&lt;sub&gt;2&lt;/sub&gt; atmosphere, which was attributed to the lower binary diffusion coefficient of the O&lt;sub&gt;2&lt;/sub&gt;/CO&lt;sub&gt;2&lt;/sub&gt; pair. The activity of the char – CO&lt;sub&gt;2 &lt;/sub&gt;gasification reaction in an O&lt;sub&gt;2&lt;/sub&gt;/CO&lt;sub&gt;2&lt;/sub&gt; environment was also investigated and revealed some contribution of this reaction to the conversion process. This was particularly noticeable at temperatures above 750 °C and under an internal diffusional controlled regime (zone II), implying displacement of oxygen out of the char particle pore volume, which allowed free reaction of CO&lt;sub&gt;2&lt;/sub&gt; on the developed pore surface. Non-isothermal kinetic analysis of the intrinsic kinetics of the oxidation reaction in O&lt;sub&gt;2&lt;/sub&gt;/CO&lt;sub&gt;2&lt;/sub&gt; revealed no particular difference compared to the O&lt;sub&gt;2&lt;/sub&gt;/N&lt;sub&gt;2&lt;/sub&gt; medium, at least when the char-CO&lt;sub&gt;2 &lt;/sub&gt;reaction was inhibited. The obtained data were used to develop a coal combustion model under O&lt;sub&gt;2&lt;/sub&gt;/CO&lt;sub&gt;2&lt;/sub&gt; conditions, which was then incorporated as a combustion module into circulating fluidized bed (CFB) computation software.&lt;/p&gt;

Combustion and Pollutant Emission Characteristics of Lignite Dried by Low Temperature Air

Lignite is a kind of coal that has high moisture content and needs to be dried before being utilized. In this article, a Chinese lignite was dried in air at 120–180°C and the changes in its physical and chemical structures after drying were investigated. The results showed that the pore volume and specific surface area of the lignite decreased after drying. Some of the methylene and methyl groups were oxidized by the oxygen in the drying air, resulting in an increase in oxygen functional groups. The combustion characteristics of the dried coals and parent coal (dry basis) were studied via thermogravimetric analysis. The total volatile yields of the dried coals increased compared to the parent coal. The burnout temperatures of the dried coals were higher than the parent coal, whereas the ignition temperatures stayed almost unchanged. An entrained flow system was set up to study the release of nitrogenous gas products during rapid pyrolysis and combustion. The HCN yields of the dried coals during pyrolysis were higher than that of the parent coal, and a similar trend was found for the NO yield during combustion. The mechanism changes of combustion and pollutant emission characteristics were discussed according to the results of the physical and chemical structure analyses.

Dairy matrix effect on the transference of rosemary (Rosmarinus officinalis) essential oil compounds during cheese making.

The use of aromatic plant extracts as ingredients may be compromised owing to low transference and activity lack in food matrixes compared with in vitro trials. Rosemary essential oil (REO) was added to sheep milk to study the transference of its compounds during the cheese-making process and to determine how cheese antimicrobial activity is modified. The volatile characterization of dairy samples was performed using headspace stir bar sorptive extraction coupled to gas chromatography/mass spectrometry (HS-SBSE/GC/MS) so that fat matrix interferences were reduced. This method detected a decrease in volatile recovery concentration of 19.33% when REO was added to milk. A total recovery volatile yield of 62.51% was measured from the initial quantification of milk to cheese, with hydrocarbon volatiles being transferred in a higher ratio (64.88%) than oxygenated ones (58.74%). No effects were observed for REO in fortified cheese on the counts of native flora necessary for ripening processes, but the total inhibition of Clostridium spp. was provoked The study of active compound transference during cheese elaboration was achieved. The antimicrobial results in fortified cheeses with REO showed a preventive effect in the case of clostridial species, which are responsible for late cheese blowing.

Thermal behaviour and kinetics of alga Polysiphonia elongata biomass during pyrolysis

The pyrolysis characteristics and kinetics of Polysiphonia elongata were investigated using a thermogravimetric analyzer. The main decomposition of samples occurred between 225°C and 485°C at heating rates of 5–40°C/min; owing to release of 78–82% of total volatiles. The heating rate effected pyrolysis characteristics such as maximum devolatilization rate and decomposition temperature. However, total volatile matter yield was not significantly affected by heating rate. The activation energy of pyrolysis reaction was calculated by model free Friedman and Kissenger–Akahira–Sunose methods and mean values were 116.23kJ/mol and 126.48kJ/mol, respectively. A variance in the activation energy with the proceeding conversions was observed for the models applied, which shows that the pyrolysis process was composed of multi-step kinetics. The Coats–Redfern method was used to determine pre-exponential factor and reaction order. The obtained parameters were used in simulation of pyrolysis process and results were in a good agreement with experimental data.

Application of uncertainty quantification methods for coal devolatilization kinetics in gasifier modeling

The focus of this research is to study sensitivity of input parameters in terms of chemical reaction kinetics of coal devolatilization using non-intrusive uncertainty quantification (UQ) methods. The effects of heating rate, pressure, and temperature on coal devolatilization have been considered. Variations in coal devolatilization kinetics and product yields were captured via Carbonaceous Chemistry for Computational Modeling (C3M) for operating conditions similar to the transport gasifier using PC Coal Lab (PCCL) kinetic package. Temperature, pressure and heating rate were considered as three input parameters, while the quantities of interest or response variables were mass fractions of CO, CO2, H2, tar, H2O, and CH4 along with total volatile yield. A direct Monte Carlo-simulation-based approach was employed to perform the UQ analysis. The correlations among the response variables were investigated by computing a correlation matrix that supports the findings of yield of devolatilization reported by various experiments in the literature. Sensitivity study of the input parameters was analyzed by using the Sobol Total Indices methodology implemented in PSUADE, an open source UQ toolbox. These findings clearly demonstrate the pronounced effect of temperature on coal devolatilization product yields, and hence will be considered as a key parameter in future studies. The preliminary study presented in this paper paves a path for incorporating uncertainty caused by chemical reaction kinetics in computational fluid dynamics based modeling of coal gasifier systems and scale-up studies.

Effect of carbonate on anaerobic acidogenesis and fermentative hydrogen production from glucose using leachate as supplementary culture under alkaline conditions

Carbonate was added into a co-culture of glucose and fresh leachate under alkaline condition to enhance batched acidogenesis and fermentative hydrogen production simultaneously. Results indicated carbonate has positive effect on both H2 production and acetic acid generation. The highest hydrogen yield (about 1.40mol/mol glucose) was obtained at [CO32-]=280mg/L with pH 8.0 and [CO32-]=560mg/L with pH 9. The dominant liquid metabolites were ethanol, acetic and butyric acid. The highest total volatile fatty acid yield (0.38g/g glucose) was achieved at [CO32-]=560mg/L with pH 9. In this case, the acetic acid yield reached 0.13g/g glucose. Verification tests using simulated wastewater as substrate were also carried out at pH 9. Results demonstrated calcium ions inhibit hydrogenogens activity while carbonate addition can alleviate the suppression effect caused by Ca2+.

I212 木質および草本系バイオマスの熱分解過程およびガス収率に及ぼす構成成分の影響(OS-11: バイオマス関連の基礎研究と利活用(1))

This paper reports on the pyrolysis of various biomass materials. In particular, the primary yields of total volatiles, tar and non-condensable gases, together with the composition of non-condensable gases, are measured as a function of temperature. The results indicate that the pyrolysis process of wood and grass biomass (tar and gas evolution process) is greatly affected by the main composition (cellulose, hemicellulose and lignin) and the linear trends with atomic H/C ratio are observed in the tar yield, total volatile yield CO, CO_2 and CH_4 yields. The volatile yields of wood and grass biomass are predicted based only on the values of ultimate analysis of the biomass.