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1.
《能源学会志》2020,93(3):1148-1162
The present study addresses pyrolysis behaviour and potential of Samanea saman seeds (SS) towards its bioenergy potential using thermogravimetric analyzer and in a cylindrical pyrolyzer (semi-batch reactor). Pyrolysis kinetic behaviour of biomass was carried out using Kissinger, Distributed Activation Energy Model (DAEM) and Miura-Maki-Integral method (MMI) while thermal pyrolysis was carried out in a cylindrical shaped semi-batch reactor. Kinetic results confirmed that the average activation energy was found 118.24 kJ mol−1, 168.70 kJ mol−1, and 97.87 kJ mol−1 for Kissinger, DAEM, and MMI model respectively. Further, thermal pyrolysis of SS biomass yielded 44.20 wt% yield of pyrolytic liquid (31.20 wt% pyrolytic oil/organic oil and 13 wt% aqueous fraction). Characterization results of pyrolytic oil showed the presence of higher viscosity (86.01 cSt), higher oxygen content (33.11%), and lower ash content (0.46 wt%) and gross heating value. FTIR analysis confirmed mainly the presence of aromatics, acid, alkene, water, and protein impurities. Gas Chromatography (GC) results declared, an increase in hydrocarbon and hydrogen gas with an increase in temperature while reduced the generation of CO and CO2. Further, GC-MS analysis of pyrolytic oil revealed the presence of higher acids (19.46%), phenols (11.01%) ethers (11.12%) and ester (7.33%) which is a potent source of oxygenated compounds. Characterization results of biochar showed the presence of higher gross heating value (23.14 MJ kg), carbon content (62.66%), volatile matter (34.15%) and lower moisture (5.14%) and BET surface area (8.20 m2 g−1). Combining these results, it can be suggested that SS biomass has the potential to produce renewable fuel and chemicals, while biochar can be used for various applications.  相似文献   

2.
A series of Li/CaO catalysts has been prepared by impregnating 0.5–5.0 wt% Li in CaO by wet chemical method. Prepared Li/CaO catalysts have been characterized by powder X-ray diffraction, scanning electron and transmission electron microscopy and Brunauer–Emmett–Teller (BET) surface area studies, in order to establish the structure and surface morphology of the catalyst. Hammett indicator test study was performed to determine the basic strength of the Li/CaO catalysts. The prepared Li/CaO catalysts have been employed as a heterogeneous catalyst for the transesterification of waste cottonseed oil (having 2.8 wt% free fatty acid contents) with ethanol. Under optimal reaction conditions viz., ethanol/oil molar ratio of 12:1, catalyst to oil weight fraction of 5% and 65 °C reaction temperature, 98% fatty acid ethyl ester yield was obtained in 2.5 h of reaction duration. Under the optimized reaction conditions, the pseudo first order constant and Arrhenius activation energy were found to be 0.03 min−1 and 70.0 kJ mol−1, respectively. Further Li/CaO catalyst was also found to be effective for the ethanolysis and methanolysis of vegetable oils having up to 3.4 wt% free fatty acids. The use of 3-Li/CaO catalyst is advantageous considering that it not only utilizes waste cottonseed oil as a feedstock, but also renewable and nontoxic alcohol, ethanol, for the biodiesel production.  相似文献   

3.
In order to compare the catalytic activity of hydrothermally synthesized nano tin oxide particles with that of red mud (byproduct of Aluminum factory), HZSM5, K2CO3, the hazelnut shell was subjected to pyrolysis in the presence of these catalysts. The nano SnO2 particles were characterized by X-ray diffraction and transmission electron microscope. The characterization results indicate that nano SnO2 particles with 3–4 nm were successfully synthesized by hydrothermal method. Effect of all catalysts on the yields of pyrolytic oil, gas and char was discussed in detail. The pyrolytic oils were further analyzed by GC–MS and FTIR techniques in order to reveal the different activity of catalysts used. The results indicate that the synthetic nano SnO2 particles make a more positive influence compared to the other catalysts. GC–MS and FTIR analysis of pyrolytic oils prove that product distribution and structure of the pyrolytic oil vary with the catalyst type.  相似文献   

4.
Nickel catalysts were synthesized by the wet impregnation of three different supports: γ-Al2O3 and alumina promoted with either 10 wt % of MgO or 10 wt% of CaO. The catalysts were evaluated in butanol steam reforming at 500 °C, atmospheric pressure, GHSV of 500,000 h−1 and 10% v/v butanol in the feed. Both promoters decreased catalyst acidity and increased basicity. The catalyst promoted with MgO exhibited the lowest acidity (1.1 μmolNH3 m−2), whereas that promoted with CaO, the highest basicity (870.7 μmolCO2 m−2). The promotion with MgO led to the highest hydrogen yield (66%) and stability, associated with its highest nickel dispersion (3.4%), lowest acidity and lowest coke formation normalized by carbon converted (3.0 mmol L mol−1). The catalyst promoted with CaO presented the most severe deactivation, associated with its lowest dispersion (1.0%) and the highest amount of encapsulated coke (3.5 mmol L mol−1).  相似文献   

5.
The black cumin seed cake (BCSC) is a by-product obtained from the black cumin seeds with cold pressing. This by-product can be utilized as a biomass feedstock for conversion to bio-oil with pyrolysis process. The BCSC samples were initially pyrolyzed on a lab-scale pyrolysis system at different values in the ranges of 300-800 °C and 0.050-0.300 L min−1 to determine the effects of operation temperature and N2 flow rate on the yields on products, respectively. Then, the bio-oil in the highest yield (wB = 44.37%) which was obtained at pyrolysis final temperature (450 °C) temperature, heating rate (35 °C min−1), particle size (dp > 850 ??m), and sweeping flow rate of 0.200 L min−1 was characterized by Fourier Transform infra-red (FT-IR) spectroscopy, gas chromatography/mass spectrometry (GC-MS) and column chromatography. Consequently, it was shown that the operating temperature and N2 gas flow rate parameters were effective on the product yields. Also, the important some physico-chemical properties of the pyrolytic oil obtained in high yield were determined as the calorific value of 38.48 MJ kg−1, the empirical formula of CH1.651O0.105N0.042S0.001, the rich chemical content containing many different chemical groups, and the density of 970.25 kg m−3, and the viscosity of 63.42 mm2 s−1. Based on the determined properties of the pyrolytic oil, it was decided that the use of pyrolytic oil derived from the BCSC may possible be for the production of the alternative liquid fuels and finely chemicals after the necessary improvements.  相似文献   

6.
An asymmetric 75 wt% Sm0.15Ce0.85O1.925-25 wt% Sm0.6Sr0.4Al0.3Fe0.7O3-δ (SDC-SSAF) dual-phase mixed ionic-electronic conducting (MIEC) oxygen-permeable membrane reactor was applied to coproduce ammonia synthesis gas (ASG, H2/N2 = 3) and liquid fuels synthesis gas (LFSG, H2/CO = 2). The effects of CH4 concentration, CH4 flow rate, steam flow rate and temperature on the performance of the membrane reactor were studied. The SDC-SSAF membrane reactor showed an excellent performance for the coproduction of ASG and LFSG. An ASG production rate of 20.7 mL cm−2 min−1, a LFSG production rate of 51.0 mL cm−2 min−1 and an oxygen permeation rate of 9.1 mL cm−2 min−1 were achieved at 925 °C. Compared with traditional industrial processes, the energy saving of this membrane reactor process is expected as high as 66.5%. The post-mortem of the membrane reactor using scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) characterization revealed that the membrane has an excellent structural stability under operation condition.  相似文献   

7.
Bimetallic nickel manganese nanoalloy-decorated graphitic nanofibers were prepared using electrospinning. The introduced catalysts were explored as an effective and inexpensive catalyst for H2 generation from ammonia borane using hydrolysis. Standard techniques were used to determine the morphology and chemical composition of the nanofibers. Characterization indicated successful formation of bimetallic nickel-manganese-decorated graphitic nanofibers. Introduced effective catalysts showed a high reusability for H2 generation using ammonia borane hydrolysis at low concentrations and temperatures. All formations of the introduced catalysts demonstrated a higher catalytic activity in H2 generation than nickel-decorated carbon nanofibers. Samples composed of 55 wt% nickel and 45 wt% manganese showed the best catalytic activity compared with other formulations. Initial turnover frequency (TOF) of this sample was 58.2 min−1, twice the TOF of the manganese-free catalyst. Kinetics and thermodynamics revealed that the catalyst concentration followed the pseudo-first order reaction while the ammonia borane concentration follow the pseudo-zero order reaction, providing activation energy of 38.9 kJ mol−1.  相似文献   

8.
Hydrogen production via chemical processes has gained great attention in recent years. In this study, Co-based complex catalyst obtained by adsorption of Co metal to Amberlite IRC-748 resin and Diaion CR11 were tested for hydrogen production from alkaline NaBH4 via hydrolysis process. Their catalytic activity and microstructure were investigated. Process parameters affecting the catalytic activity, such as NaOH concentration, Co percentage and catalyst amount, as well as NaBH4 concentration and temperature were investigated. Furthermore, characteristics of these catalysts were carried out via SEM, XRD and FT-IR analysis. Hydrogen production rates equal to 211 and 221 ml min−1 gcat−1 could be obtained with Amberlite IRC-748 resin and Diaion CR11 Co based complex catalysts, respectively. The activation energies of the catalytic hydrolysis reaction of NaBH4 were calculated as 46.9 and 59.42 kJ mol−1 for Amberlite IRC-748 resin and Diaion CR11 based catalysts respectively kJ mol−1 from the system consisting of 3% Co, 10 wt% NaBH4 and 7 wt% NaOH as well as 50 mg catalyst dosage. It can be concluded that Co-based resins as catalysts for hydrogen production is an effective alternative to other catalysts having higher rate.  相似文献   

9.
The Ni/pillared-bentonite catalysts with high BET area were synthesized and used in dry reforming reaction. The effects of different parameters such as calcination temperature, OH/Al3+ ratio, temperature and time of pillaring process and the content of nickel on the textural and catalytic properties of the synthesized catalysts were studied. The results indicated that the 15 wt% Ni catalyst supported on pillared bentonite prepared under specified conditions (OH/Al3+ = 2.2, pillaring temperature of 40 °C and pillaring time of 3 h) possessed the highest BET area (90.80 m2/g). Also, this catalyst possessed higher catalytic activity and stability with lower amount of deposited carbon in comparison to other prepared catalysts in methane reforming with CO2.  相似文献   

10.
《能源学会志》2020,93(1):303-311
Pyrolysis of Ulva prolifera macroalgae (UM), an aquatic biomass, was carried out in a fixed-bed reactor in the presence of three zeolites based catalysts (ZSM-5, Y-Zeolite and Mordenite) with the different catalyst to biomass ratio. A comparison between non-catalytic and catalytic behavior of ZSM-5, Y-Zeolite and Mordenite catalyst in the conversion of UM showed that is affected by properties of zeolites. Bio-oil yield was increased in the presence of Y-Zeolite while decreased with ZSM-5 and Mordenite catalyst. Maximum bio-oil yield for non-catalytic pyrolysis was (38.5 wt%) and with Y-Zeolite catalyst (41.3 wt%) was obtained at 400 °C respectively. All catalyst showed a higher gas yield. The higher gas yield might be attributed to that catalytic pyrolysis did the secondary cracking of pyrolytic volatiles and promoted the larger small molecules. The chemical components and functional groups present in the pyrolytic bio-oils are identified by GC–MS, FT-IR, 1H-NMR and elemental analysis techniques. Phenol observed very less percentage in the case of non-catalytic pyrolysis bio-oil (9.9%), whereas catalytic pyrolysis bio-oil showed a higher percentage (16.1%). The higher amount of oxygen present in raw biomass reduced significantly when used catalyst due to the oxygen reacts with carbon and produce (CO and CO2) and water.  相似文献   

11.
Soybean oil was pyrolyzed with various catalysts in a fixed-bed reactor under nitrogen flow at 420 and 450 °C. The H-ZSM5 catalysts (molar ratio SiO2/Al2O3 = 28, 40, and 180) and 2 wt% (Ga, Al or Cu) impregnated MCM41 catalysts were used in order to investigate the effect of catalysts during the pyrolysis process. The gas products in all experiments were mainly methane, ethane and propylene. The liquid products in the presence of H-ZSM5 catalysts were mainly aromatic components while those with metal/MCM41 catalysts were a mixture of alkanes, alkenes, alkadienes, aromatic and carboxylic acids. The highest coke yield of 4.4 wt% was obtained with Ga/MCM41 catalyst at the pyrolysis temperature of 420 °C. The effect of catalysts on product yield and composition was systematically investigated.  相似文献   

12.
Hydrogen is a promising candidate to substitute the fossil fuels. However, the efficient hydrogen storage technologies restrict the commercial applications. Developing new catalysts with high activity and selectivity is important for the dehydrogenation reaction in N-ethylcarbazole/dodecahydro-N-ethylcarbazole (NECZ/12H-NECZ) hydrogen storage system. In this work, a series of Pd-M/Al2O3 (M = Co, Ni and Cu) bimetallic catalysts are synthesized successfully and show good performance in the dehydrogenation reaction of 12H-NECZ than the commercial Pd/Al2O3 catalyst. The Pd1Co1/Al2O3 catalyst (Practical Pd content = 2.4136 wt%) showed the highest catalytic performance with 95.34% H2 release amount, TOF of 230.5 min−1 and 85.4% selectivity of NECZ. Combined with the characterization analysis, it can be proposed that the dehydrogenation performance of 12H-NECZ is dependent on the alloy phases, reasonable electronic structures and nanoparticle size of catalysts. The fine-tuned alloy degree and appropriate nanoparticle size of Pd1Co1/Al2O3 bring the 17.7% increase of H2 release amount and 99.5% increase of NECZ selectivity than those of Pd/Al2O3. For the bimetallic catalysts, the enhancement of selectivity of NECZ is mainly from the increase of the kinetic constant of rate-limiting step.  相似文献   

13.
Fixed-bed slow pyrolysis experiments have been conducted on a sample of safflower seed to determine particularly the effects of pyrolysis temperature, heating rate, particle size and sweep gas flow rate on the pyrolysis product yields and their chemical compositions. The maximum oil yield of 44% was obtained at the final pyrolysis temperature of 500°C, particle size range of +0.425–1.25 mm, with heating rate of 5°C min−1 and sweep gas (N2) flow rate of 100 cm3 min−1 in a fixed-bed lab-scale reactor. Chromatographic and spectroscopic studies on the pyrolytic oil showed that the oil obtained from safflower seed can be used as a renewable fuel and chemical feedstock with a calorific value of 41.0 MJ/kg and empirical formula of CH1.92O0.11N0.02.  相似文献   

14.
A series of 10 wt%Ni/CeO2–ZrO2–Al2O3 (10%Ni/CZA) coated monolith catalysts modified by CaO with the addition amount of 1 wt%~7 wt% are prepared by incipient-wetness co-impregnation method. Effects of CaO promoter on the catalytic activity and anti-coking ability of 10%Ni/CZA for steam reforming of n-decane are investigated. The catalysts are characterized by N2 adsorption-desorption, XRD, SEM-EDS, TEM, NH3-TPD, XPS, H2-TPR and Raman. The results show that specific surface area and pore volume of as-prepared catalysts decrease to some extent with the increasing addition of CaO. However, the proper amounts of CaO (≤3 wt%) significantly enhance the catalytic activity in terms of n-decane conversion and H2 selectivity mainly due to the improved dispersion of NiO particles (precursor of Ni particles). As for anti-coking performance, reducibility of CeO2 in composite oxide support CZA is promoted by CaO resulting in providing more lattice oxygen, which favors suppressing coke formation. Moreover, the addition of CaO reduces the acidity of 10%Ni/CZA, especially the medium and strong acidity. But far more importantly, a better dispersion of NiO particles obtained by proper amounts of CaO addition is dominant for the lower carbon formation, as well as the higher catalytic activity. For the spent catalysts, amorphous carbon is the main type of coke over 10%Ni–3%CaO/CZA, while abundant filamentous carbon is found over the others.  相似文献   

15.
The transesterification of palm oil to methyl esters (biodiesel) was studied using KOH loaded on Al2O3 and NaY zeolite supports as heterogeneous catalysts. Reaction parameters such as reaction time, wt% KOH loading, molar ratio of oil to methanol, and amount of catalyst were optimized for the production of biodiesel. The 25 wt% KOH/Al2O3 and 10 wt% KOH/NaY catalysts are suggested here to be the best formula due to their biodiesel yield of 91.07% at temperatures below 70 °C within 2–3 h at a 1:15 molar ratio of palm oil to methanol and a catalyst amount of 3–6 wt%. The leaching of potassium species in both spent catalysts was observed. The amount of leached potassium species of the KOH/Al2O3 was somewhat higher compared to that of the KOH/NaY catalyst. The prepared catalysts were characterized by using several techniques such as XRD, BET, TPD, and XRF.  相似文献   

16.
In this study, nickel, nickel-chromium alloy, and nickel-vanadium alloy were coated to form a thin film on the slides prepared by magnetron sputtering process, which were used as a catalyst for the hydrolysis of alkaline sodium borohydride. Factors, such as the temperature of the solution, amount of the catalyst, initial pH of the solution and the performance of these catalysts on hydrogen generation rate were investigated using response surface methodology. Moreover, the catalysts were characterized using XRD and FE-SEM/EDS analyses. Utilizing the obtained optimum conditions of the response surface methodology estimation, the maximum hydrogen generation rate was 35,071 mL min−1 gNiV−1 from NiV catalyst at 60 °C, pH 6, and 1.75 g catalyst conditions. Under the same experiment conditions, the maximum hydrogen generation rates of Ni and NiCr catalyst systems are 28,362 mL min−1 gNi−1, and 30,608 mL min−1 gNiCr−1, respectively.  相似文献   

17.
This paper deals with production of pyrolytic oil from neem seed and using this pyrolytic oil in the form of blend with fossil diesel to study the performance and emission characteristics in CI engine. Thermal and catalytic pyrolysis of non edible neem seed was performed in a slow fixed bed pyrolyser to produce pyrolytic oil. Maximum pyrolytic oil obtained in thermal pyrolysis was 55% wt and in catalytic pyrolysis was 60% wt using both Al2O3 and K2CO3 catalysts followed by 41% wt and 38% wt for zeolite and kaolin catalysts respectively. The catalytic pyrolysis improved pH and calorific values of 12.4% and 14.4% respectively as compared to thermal pyrolysis. Blends of neem seed catalytic pyrolytic oil (NB) with fossil diesel in the ratio of 5% (NB5) and 10% (NB10) by volume were tested on an unmodified CI engine. Brake thermal efficiency (BTE) was lower at part load conditions and higher at full load condition up to 3.7% in the case of blends as compared to fossil diesel operation. Higher Brake Specific Fuel Consumption (BSFC) was observed in the case of NB5 blend on all load conditions, up to 23.9%. Reduction in emission levels were observed for HC (46.9%), CO (42.2%), CO2 (29.8%) and NOx (20.7%) at full load condition. This study observed that neem seed catalytic pyrolytic oil is a potential renewable and sustainable green fuel.  相似文献   

18.
In recent years, catalytic hydrolysis of sodium borohydride is considered to be a promising approach for hydrogen generation towards fuel cell devices, and highly efficient and noble-metal-free catalysts have attracted increasing attention. In our present work, Co3O4 nanocubes are synthesized by solvothermal method, and then vapor-phase phosphorization treatment is carried out for the preparation of novel Co−O−P composite nanocatalysts composed of multiple active centers including Co, CoO, and Co2P. For catalyst characterization, field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), energy dispersive spectrometry (EDS), X-ray diffraction (XRD) and X-ray photoelectric spectroscopy (XPS) are conducted. Optimal conditions for catalyst preparation and application were investigated in detail. At room temperature (25 °C), maximum hydrogen generation rate (HGR) is measured to be 4.85 L min−1 g−1 using a 4 wt% NaBH4 − 8 wt% NaOH solution, which is much higher than that of conventional catalysts with single component reported in literature. It is found that HGR remarkably increases with the increasing of reaction temperature, and apparent activation energy for catalytic hydrolysis of NaBH4 is calculated to be 63 kJ mol−1. After reusing for five times, the Co−O−P composite nanocatalysts still retains 78% of the initial activity.  相似文献   

19.
The performance of three catalysts during slow catalytic pyrolysis of rapeseed cake from 150 to 550 °C over a time period of 20 min followed by an isothermal period of 30 min at 550 °C was investigated. Na2CO3 was premixed with the rapeseed cake, while γ-Al2O3 and HZSM-5 were tested without direct biomass contact. Catalytic experiments resulted in lower liquid and higher gas yields. The total amount of organic compounds in the pyrolysis liquid was considerably reduced by the use of a catalyst and decreased in the following order: non-catalytic test (34.06 wt%) > Na2CO3 (27.10 wt%) > HZSM-5 (26.43 wt%) > γ-Al2O3 (21.64 wt%). In contrast, the total amount of water was found to increase for the catalytic experiments, indicating that dehydration reactions became more pronounced in presence of a catalyst. All pyrolysis liquids spontaneously separated into two fractions: an oil fraction and aqueous fraction. Catalysts strongly affected the composition and physical properties of the oil fraction of the pyrolysis liquid, making it promising as renewable fuel or fuel additive. Fatty acids, produced by thermal decomposition of the biomass triglycerides, were converted into compounds of several chemical classes (such as nitriles, aromatics and aliphatic hydrocarbons), depending on the type of catalyst. The oil fraction of the pyrolysis liquid with the highest calorific value (36.8 MJ/kg) was obtained for Na2CO3, while the highest degree of deoxygenation (14.0 wt%) was found for HZSM-5. The aqueous fraction of the pyrolysis liquid had opportunities as source of added-value chemicals.  相似文献   

20.
In this paper, we have evaluated the potential of organic acid (mixture of acetic, formic and propionic acid) leaching of biomass and subsequent fast pyrolysis to increase the organic oil, sugars and phenols yield by varying the fluidized bed temperature between 360 °C and 580 °C (360 °C, 430 °C, 480 °C, 530 °C, and 580 °C). The pyrolysis of acid leached pinewood resulted in more organic oil and less water and residue compared to untreated pinewood over the whole temperature range. Below 500 °C the difference was most profound; for acid leached pinewood at 360 °C the organic oil was already 650 g kg−1 pine with a sugar yield of 230 g kg−1 pine. At this low pyrolysis temperature no bed agglomeration was observed for acid leached pine whereas at the higher temperatures tested agglomerates were found, which were identified to be clusters of fluidization sand glued together by sticky pyrolysis products (melt). Low reactor temperatures also favored the production of monomeric phenols, though their absolute yields remained low for both untreated and leached pine (maximum: 23 g kg−1 pine, 80 g kg−1 lignin). GPC, GC/MS and UV-fluorescence spectroscopy showed that acid leaching did not influence significantly the yield and molecular size of the aromatic fraction in the produced pyrolysis oils. Back impregnation of the removed AAEMs into leached biomass revealed that the effects of the applied acid leaching, both with respect to the product yields and bed agglomeration, can be mainly assigned to the removal of AAEMs.  相似文献   

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