A consistency mapping for the effects on enzymatic hydrolysis sugar yield using two sugar yield definitions in cellulosic biofuel manufacturing

Two different sugar yield definitions (cellulose-based and biomass-based) were used in reported studies investigating the relationship between biomass particle size and enzymatic hydrolysis sugar yield. It is noticed that these reported relationships are not consistent if sugar yield is defined differently. The literature does not contain any reports on the effects of sugar yield definition on the relationship between biomass particle size and enzymatic hydrolysis sugar yield. This paper presents a consistency mapping to show under what conditions the relationships are consistent (or inconsistent) when these two definitions are used. The application of this mapping is illustrated via an experimental study with poplar wood biomass on the relationship between biomass particle size and enzymatic hydrolysis sugar yield using both sugar yield definitions. The application of this mapping is also illustrated via data reported in the literature. Not limited to particle size, this mapping is applicable to investigations of the relationships between a variety of parameters (biomass type, pretreatment condition, etc.) and enzymatic hydrolysis sugar yield.     

Improvement in energy recovery from Chlorella sp. biomass by integrated dark-photo biohydrogen production and dark fermentation-anaerobic digestion processes

Chlorella sp. biomass was used as the sole substrate for the production of hydrogen and methane through integrated dark fermentation (DF) and photo-fermentation (PF), and DF and anaerobic digestion (AD) processes. Prior to use in fermentations, the biomass was pretreated by acid-hydrothermal method, which yielded a maximum reducing sugar yield of 162.9 ± 4.2 mg g-biomass⁻¹. The use of the microalgal hydrolysate to produce hydrogen by DF gave a hydrogen yield (HY) of 47.2 ± 1.1 mL g-volatile-solids⁻¹ (VS). The subsequent use of the hydrogenic effluent in PF gave a HY of 125.0 ± 1.5 mL g-VS⁻¹, while AD of the hydrogenic effluent gave a methane yield of 152.8 ± 1.3 mL g-VS⁻¹. The total energy yield attained by the use of DF alone, the integrated DF-PF, and DF-AD processes were 0.51, 1.86 and 5.98 kJ g-VS⁻¹, respectively. These results indicate that the integrated DF-AD process was effective in recovering energy from Chlorella sp. biomass. However, an energy balance analysis indicated that the process was not energetically feasible due to the high energy demand for the acid-hydrothermal pretreatment.     

Separation of L‐aspartic acid and L‐glutamic acid mixtures for use in the production of bio‐based chemicals

BACKGROUND: Amino acids are promising feedstocks for the chemical industry due to their chemical functionality. They can be obtained by the hydrolysis of potentially inexpensive protein streams such as the byproduct of biofuel production. However, individual amino acids are required before they can be used for the further production of chemicals. Here, the separation of L‐aspartic acid (Asp) and L‐glutamic acid (Glu) mixture, which can be isolated from protein hydrolysis solutions at low pH or from electrodialysis of complex amino acid mixtures, was studied. RESULTS: Glu was converted into L‐pyroglutamic acid (pGlu) which can be separated from the mixture of Asp and Glu due to its higher solubility in water. The conversion was carried out under aqueous or melt conditions. Under aqueous conditions, the conversion was studied as a factor of time, temperature and the amount of Glu. The conversion was specific with high yield and not effected by Asp. After pGlu was separated from Asp and residual Glu by solubility difference, it can be transferred back to Glu through hydrolysis. CONCLUSION: The conversion of Glu to pGlu is specific and can be applied to separation Asp and Glu for their use in the production of bio‐based chemicals. Copyright © 2012 Society of Chemical Industry     

Value‐added bioconversion of biomass by solid‐state fermentation

The value‐added bioconversion of biomass is necessary due to the depletion of fossil fuels and deterioration of the global environment situation. Based on the analysis of characteristics of solid materials and the applicability of solid agro‐industrial residues used as feedstock for solid‐state fermentation (SSF), the authors established a value‐added bioconversion system for biomass using the key technology SSF. This article gives an overview of biomass bioconversion by SSF and the corresponding advances achieved in recent years. Copyright © 2012 Society of Chemical Industry     

The effect of wood biomass blending with pulverized coal on combustion characteristics under oxy-fuel condition

In this study, combustion from the co-firing of coal and wood biomass, and thermal characteristics such as ignition temperature, burn-out temperature, and activation energy were discussed using a thermogravimetric analyzer (TGA). We investigated the effects of biomass blending with two kinds of pulverized coal (bituminous Shenhua, and sub-bituminous Adaro) under air and oxy-fuel conditions. The coal fraction in the blended samples was set to 1, 0.8, and 0.5. The oxygen fraction in the oxidant was set to 0.21, 0.3, 0.5, and 0.8. The ignition temperature was governed by the fuel composition, particularly in the blended biomass which has a much higher content of volatile matter comparing to coal. However, the burnout temperature, which shows a strong relationship with char combustion, depended on the oxidant ingredients rather than on the fuel components. Thermal characteristics such as ignition, burnout temperature, reaction region, and heat flow were very similar between air and a 0.3 oxygen concentration under oxy-fuel conditions with Shenhua coal.     

Initial moisture effects on herbal biomass torrefaction behavior: Gaseous products evolution and char structure analysis

Initial moisture effects on biomass torrefaction were investigated by thermogravimetric (TG) and Fourier transform infrared spectrometer (FTIR) methods. Mass degradation properties, gaseous products’ evolution characteristics, and biomass char chemical structural features were studied. Results show that during torrefaction process, the evaporation of water will create a porous structure inside the solid particles, hence extend the mass loss time intervals. Gaseous products’ evolutions were favored, while tar was reduced because of enhanced secondary decomposition. Char structure analysis suggested that –OH stretch was slightly strengthened through water molecule decomposition and other radical reactions, which would increase the reactivity of char gasification and combustion.     

Thermal Behavior and Kinetics of Raw/Pyrolytic Wood and Coal Blends during Co-combustion Process

The thermal properties of raw wood (RW)biomass,corresponding pyrolytic wood (PW)biomass,and their blends with anthracite coal (AC)were evaluated under combustion conditions with a thermogravimetric analysis (TGA)method.The blending ratios of the biomass with AC ranging from 0 to 100 mass% were taken into consider-ation to investigate the thermal behavior and kinetics of these blends during their co-combustion.For blends with dif-ferent ratios of the RW to AC and 100% AC (100 AC),two distinct mass loss peaks related to the release or com-bustion process of the volatiles and the combustion of the char were noted.The addition of a higher ratio of RW or PW into AC can improve the combustion process of the blends.The thermal behavior of the RW/AC or PW/AC blends could not be characterized by a simple linear correlation of their pure material thermal behavior.With the RW/PW addition ratios varying from 25 mass% to 80 mass%,the apparent activation energy of the blends gradually decreased from 48.46 to 34.93 kJ/mol and from 82.74 to 37.81 kJ/mol for the RW/AC and PW/AC blends,re-spectively,with high correlation coefficient (R2 )values ranging from 0.995 6 to 0.998 4.     

Compositional and structural study of ash deposits spatially distributed in superheaters of a large biomass-fired CFB boiler

Recognizing the nature and formation progress of the ash deposits is essential to resolve the deposition problem hindering the wide application of large-scale biomass-fired boilers. Therefore, the ash deposits in the superheaters of a 220 t/h biomass-fired CFB boiler were studied, including the platen (PS), the high-temperature (HTS), the upper and the lower low-temperature superheaters (LTS). The results showed that the deposits in the PSs and HTSs were thin (several millimeters) and compact, consisting of a yellow outer layer and snow-white inner layer near the tube surface. The deposits in the upper LTS appeared to be toughly sintered ceramic, while those in the lower LTS were composed of dispersive coarse ash particles with an unsintered surface. Detailed characterization of the cross-section and the initial layers in the deposits revealed that the dominating compositions in both the PSs and the HTSs were Cl and K (approximately 70%) in the form of KCl. Interestingly, the cross-section of the deposition in the upper LTS exhibited a unique lamellar structure with a major composition of Ca and S. The contents of Ca and Si increased from approximately 10% to approximately 60% in the deposits from the high temperature surfaces to the low temperature ones. It was concluded that the vaporized mineral matter such as KCl played the most important role in the deposition progress in the PS and the HTS. In addition, although the condensation of KCl in the LTSs also happened, the deposition of ash particles played a more important role.     

新型镍基镁渣催化重整松木热解挥发分焦油析出特性研究

采用过量浸渍法制备了镍基镁渣催化剂，并在小型气流床气化炉上开展了松木热解挥发分的催化重整研究。评估了煅烧/催化温度、镍含量和水碳比对焦油组分的影响，同时在不同煅烧/催化温度下与Ni/γ-Al₂O₃催化剂进行了裂解焦油性能的对比。采用比表面积测试（BET）、X射线衍射（XRD）、扫描电镜（SEM）和透射电镜（TEM）对催化剂进行了表征。结果表明，当镍含量为3%，煅烧/催化温度为800℃，水碳比为0.5时，镍基镁渣催化剂表现出最优异的催化裂解焦油能力：大幅度降低了重质多环芳烃的相对含量，并且焦油转化率达到95.69%，同时焦油露点温度降至40.2℃。XRD结果表明，Ni、Fe、Ca、Mg相互作用可以形成多种活性中心，进而协同提高催化剂活性。