期刊导航

Totally found 2194 items.

  • [期刊] Process design and economic assessment of butanol production from lignocellulosic biomass via chemical looping gasification
    Biomass chemical looping gasification (BCLG) is a promising gasification technology to convert biomass into synthesis gas with no need for molecular oxygen. In this study, a novel process for butanol production from lignocellulosic biomass based on BCLG is proposed. The proposed process is simulated using Aspen Plus and composed of main sub-processes such as BCLG, acid gas removal, synthesis and separation of alcohol. An economic assessment is conducted according to results of Aspen Plus model. The equipment cost for the proposed process is evaluated as 4.65 x 10(8) CNY and the minimum butanol selling price is estimated as 9.35 CNY/kg. Sensitivity analysis of the process indicates that pine sawdust price has the largest effect on the minimum butanol selling price followed by total equipment cost and plant lifetime. Finally, impacts of CO conversion and carbon tax on the minimum butanol selling price are explored.
  • [期刊] In-situ catalytic pyrolysis upgradation of microalgae into hydrocarbon rich bio-oil: Effects of nitrogen and carbon dioxide environment
    Pyrolysis of Spirulina Platensis (SP) microalgae was carried out under different reaction environment such as nitrogen (N-2) and carbon dioxide (CO2) at different reaction temperatures of 300, 350, 400, 450 and 500 degrees C. Catalytic upgradations were examined over solid acid (ZSM-5) and solid base (MgO) catalyst, and with ZSM-5-MgO catalysts mixtures. Results showed, pyrolysis of non-catalytic biomass yielded maximum bio-oil of 43.6% under N-2. However catalytic upgradation in CO2 environment produced lower bio-oil due to the coke formation. Maximum bio-oil (46.2 wt%) was obtained with basic metal MgO catalyst in N-2 environment compared to other catalyst and environments. Mixture of MgO-ZSM-5 catalyst improved the bio-oil yield (37.8-48.6 wt%) compared to individual catalytic reaction under N-2 and CO2. Higher high heating value (HHV) was observed in catalytic bio-oil 36.8 MJ/Kg. Bio-oil (catalytic) analysis revealed that 64-70% of compounds are in hydrocarbon range. Bio-oil was rich in hydrocarbons of C-7-C-18 range with less oxygenated compounds.
  • [期刊] In-situ catalytic pyrolysis upgradation of microalgae into hydrocarbon rich bio-oil: Effects of nitrogen and carbon dioxide environment
    Pyrolysis of Spirulina Platensis (SP) microalgae was carried out under different reaction environment such as nitrogen (N-2) and carbon dioxide (CO2) at different reaction temperatures of 300, 350, 400, 450 and 500 degrees C. Catalytic upgradations were examined over solid acid (ZSM-5) and solid base (MgO) catalyst, and with ZSM-5-MgO catalysts mixtures. Results showed, pyrolysis of non-catalytic biomass yielded maximum bio-oil of 43.6% under N-2. However catalytic upgradation in CO2 environment produced lower bio-oil due to the coke formation. Maximum bio-oil (46.2 wt%) was obtained with basic metal MgO catalyst in N-2 environment compared to other catalyst and environments. Mixture of MgO-ZSM-5 catalyst improved the bio-oil yield (37.8-48.6 wt%) compared to individual catalytic reaction under N-2 and CO2. Higher high heating value (HHV) was observed in catalytic bio-oil 36.8 MJ/Kg. Bio-oil (catalytic) analysis revealed that 64-70% of compounds are in hydrocarbon range. Bio-oil was rich in hydrocarbons of C-7-C-18 range with less oxygenated compounds.
  • [期刊] Impact of dilute acid pretreatment conditions on p-coumarate removal in diverse maize lines
    Prior work has identified that lignins recovered from dilute acid-pretreated corn stover exhibit superior performance in phenol-formaldehyde resins used in wood adhesive applications when compared to diverse processmodified lignins derived from other sources. This improved performance is hypothesized to be due to the higher content of unsubstituted phenolic groups specificallyp-coumarate lignin esters. In this work, a diverse set of corn stover samples are employed that exhibit diversity in p-coumarate content and total lignin content to explore the relationship between dilute acid pretreatment conditions, p-coumarate ester hydrolysis, xylan solubilization, and the resulting glucose enzymatic hydrolysis yields. The goal of this study is to identify pretreatment conditions that preserve a significant fraction of the p-coumarate esters while simultaneously achieving high enzymatic hydrolysis yields. Kinetic parameters for p-coumarate ester hydrolysis were quantified and pretreatment-biomass combinations were identified that result in glucose hydrolysis yields of more than 90% while retaining nearly 50 mg p-coumarate/g lignin.
  • [期刊] Granule-based immobilization and activity enhancement of anammox biomass via PVA/CS and PVA/CS/Fe gel beads
    Granule-based immobilization of anammox biomass assisted by polyvinyl alcohol/chitosan (PVA/CS) and PVA/CS/Fe gel beads was studied, via the operation of three identical up-flow reactors (R1 without gel beads, R2 with PVA/CS, R3 with PVA/CS/Fe) for 203 days. In the end, the nitrogen removal rates (NRR) were 5.3 +/- 0.4, 10.0 +/- 0.3 and 13.9 +/- 0.5 kg-N m(-3) d(-1) for R1, R2 and R3, respectively. The porous PVA/CS and PVA/CS/Fe created a suitable eco-niche for anammox bacteria to grow and attach, thus being retained in the reactor. The EPS entangles newly grown cells within the gel beads, resulting in compact aggregation. The interaction between Fe ions added to PVA/CS/Fe gel beads and negatively charged EPS groups strongly promoted granule strength and compactness. The immobilization method proposed by this study was found to effectively improve biomass retention in the reactors, which is promising for advanced anammox process applications.
  • [期刊] The residue from the acidic concentrated lithium bromide treated crop residue as biochar to remove Cr (VI)
    In this work, the hydrolysis residue produced from the acidic concentrated lithium bromide hydrolysis (ALBH) of wheat straw, corn stover and elephant grass were characterized as biochar. The ALBH biochar as the black power had high content of carbon (49.65-55 wt%), specific surface areas (4.53-7.79 m(2)/g), porous structures (micropores, mesopores and macropores) and abundant oxygen functional groups (hydroxy, carbonyl, ester and ketone groups). These properties made ALBH biochar as a potential adsorbent for environmental remediation, with relatively high removal efficiency for a variety of heavy metal ions, especially hexavalent chromium (Cr (VI)). Therefore, ALBH technology may be an efficient strategy for synthesis of bio-char along with fermentable sugars, which met the concern of sustainability and green chemistry.
  • [期刊] Volatile-char interactions during biomass pyrolysis: Understanding the potential origin of char activity
    To understand the potential origin of char activity responsible for volatile evolution during biomass pyrolysis, the interactions between benzyl phenyl ether (BPE, a typical lignin dimer) and pinewood chars prepared under a series of thermal, acidy, and steamy conditions were investigated. The results showed the activity of low-temperature char on BPE conversion was mainly attributed to the surface O-containing functional groups. The BPE conversion decreased as the temperature for char preparation raised, resulting from the elimination of char surface functional groups to a large degree at high temperature. The low activity of high-temperature char on BPE conversion could be recovered by acid-washing to release metal-occupied carbon based active sites (e.g., small aromatic rings), and further promoted by steam activation to modify the surface property and porous structure, finally achieving a full conversion of BPE and high selectivity to the products of phenol and toluene.
  • [期刊] Biochemical conversion of sugarcane bagasse into the alcohol fuel mixture of isopropanol-butanol-ethanol (IBE): Is it economically competitive with cellulosic ethanol?
    This work presents a techno-economic analysis of the production of isopropanol, butanol, and ethanol (IBE) from sugarcane bagasse using clostridia and compares IBE with cellulosic ethanol for the minimum selling price (MSP) and sustainability aspects. The MSPs of the fuels are similar (15 USD/GJ) provided that glucose and xylose are effectively utilized in both processes, and the IBE process is equipped with a genetically-modified Clostridium species with enhanced IBE yield and a highly productive continuous bioreactor with integrated product recovery. Notably, these technologies can reduce the size (from 23 x 3785-m(3) to 3 x 3027-m(3) fermentation tanks) and the wastewater footprint (from 50 to 10 m(3)/m(3) IBE) of the IBE plant. Furthermore, given that the production of either fuel results in a similar increase in the value created by the sugarcane biorefinery and its energy efficiency, the alcohol mixture produced by clostridia is a promising alternative to the less energy-dense ethanol fuel.
  • [期刊] Microbial community in in-situ waste sludge anaerobic digestion with alkalization for enhancement of nutrient recovery and energy generation
    Microbial community in in-situ waste sludge anaerobic digestion with alkalization for enhancement of nutrient recovery and energy generation was studied. Firmicutes, Proteobacteria and Bacteroidetes phylum became the majority in the microbial community, especially Firmicutes showed the predominate role in the community due to its thick cell wall structure, potential ability hydrolysis and hydrogenogenic acidogenesis. Anaerobic digestion with alkalization caused the obvious microbial diversity decrease, and over 50% of minority bacteria grew up in quantity from original sludge. Phylum of Firmicutes developed by themselves having few interactions with other bacteria, partly contributing to its rapid growth in anaerobic digestion with alkalization. The decrease of hydrocarbon degradation, and the increase of both fermentation and reductive acetogenesis in microbial community, indicating the promotion of short chain fatty acids production, especially acetic acid which is the key intermediate products for nutrient recovery and energy generation.
  • [期刊] Biodiesel production by direct transesterification of wet spent coffee grounds using switchable solvent as a catalyst and solvent
    Spent coffee grounds (SCGs) are a promising material for sustainable preparation of biodiesel. This study proposed a new approach for biodiesel synthesis from wet SCGs using 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) as both a green solvent and catalyst. The optimal reaction conditions were determined as a methanol amount of 6.25 mL/g of wet SCGs, DBU amount of 14.46 mL/g of wet SCGs, temperature of 60.2 degrees C, and reaction time of 28.65 min through response surface methodology. Under these conditions, the maximum biodiesel yield was 97.18%. Notably, DBU polarity could be regulated reversibly, facilitating its reusability and a simple process for product separation. Under optimal conditions, DBU could be potentially reused for at least 10 cycles to yield high amounts of biodiesel. This study suggests that the switchable solvent-assisted direct transesterification of wet SCGs is a potential, efficient, cost-effective, and eco-friendly approach for biodiesel synthesis.
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