Liquefaction Catalysts Research Articles

23.1t/d PSUにおける石炭液化誠験 : 生成物収率に及ぼす液化触媒種の影響

23.1t/d PSUにおける石炭液化誠験 : 生成物収率に及ぼす液化触媒種の影響

112.150t/d規模石炭液化パイロットプラントによる開発研究[V] : 液化触媒製造設備の最適化

112.150t/d規模石炭液化パイロットプラントによる開発研究[V] : 液化触媒製造設備の最適化

Ag-doped M2O3 nanoflakes as effective catalyst for lignin liquefaction in supercritical methanol medium

Solid biomasses can be exploited as an effective source of energy if they can be converted into liquid and gaseous fuels. In this study, highly crystalline Ag–Mn2O3 nanoflakes are introduced as effective catalyst for cracking of lignin into alcohols in supercritical methanol medium. The introduced catalyst was synthesized by a sol–gel process. Typically, mixing of manganese acetate, silver nitrate and citric acid solutions led to form a continuous gel when the pH was kept at 7. Drying, grinding and calcination (at 600°C) of the obtained gel resulted in producing Ag-Mn2O3 nanoflakes. The utilized XRD, SEM, FE-SEM and TEM analyses affirmed the concluded structure and morphology. The introduced inorganic nanostructure could successfully catalyze degradation of lignin into liquid alcohols when the solid biomass was catalytically treated in an autoclave reactor in presence of methanol at 180°C. The experimental results indicated that maximum lignin dissolution of 42.5wt% can be obtained when the catalyst content is kept at 17wt% and treatment time of 2h. Overall, the present study opens new avenue for the stable ceramic catalysts for solid biowastes conversion into valuable products.

Thermochemical Depolymerization of Biomass

Biomass is considered as a clean source of renewable energy, utilization of biomass may reduce the environmental pollutions. This paper presents a review of the chemistry and process of depolymerization of biomass; which results in production of oil and gaseous fuels from such important renewable energy source. Also, thermal hydro-cracking of lignin enhances coal liquefaction by producing intermediates which then react further with coal producing lower molecular weight material, which more desirable. Enhancement of coal conversion due to the addition of lignin is found to be a function of time. It is dependent upon temperature of reaction and the type of lignin used. By increasing the ratio of lignin to coal will result in deploymerizing larger portions of coal. This indicates that it can be used as a catalyst in liquefaction of higher molecular weight of hydrocarbon solid fuels such as coal and heavy petroleum fuels.

C4H8SO3Hmim]HSO4 as an efficient catalyst for direct liquefaction of bagasse lignin: Decomposition properties of the inner structural units

Catalytic valorization of renewable aromatic lignin is attracting increasing attention. In this study, an efficient method for direct liquefaction of sugarcane bagasse lignin using acidic ionic liquid (IL) 1-(4-sulfobutyl)-3-methyl imidazolium hydrosulfate ([C4H8SO3Hmim]HSO4) is presented. The relationships between catalyst dosage, reaction condition parameters and degree of liquefaction, and the structure and elemental composition of liquefaction residue were investigated. The transformation performances of three molecular structural units (guaiacyl, syringyl, and hydroxyphenyl units) of bagasse lignin were also intensively examined using gas chromatography-mass spectrometry, elemental analysis, Fourier transform infrared spectrometry, and proton nuclear magnetic resonance characterization. The results demonstrated that the dual-functionalized acidic IL exhibited excellent catalytic performance in the direct liquefaction process. More than 65% degree of liquefaction was achieved under optimized conditions, yielding 13.5% of useful aromatic fine chemicals such as phenol, 4-ethylphenol, and guaiacol. The p-hydroxyphenyl unit of lignin was the most flexible, followed by the guaiacyl unit, whereas the syringyl group was the most refractory. Furthermore, the catalytic mechanism was proposed.

Effects of heterogeneous catalyst in hydrothermal liquefaction of dried distillers grains with solubles

Hydrothermal liquefaction of biomass is a promising technology for production of biofuels. In this work, the catalytic effect of a nanocrystalline zirconia catalyst on hydrothermal liquefaction of dried distiller’s grains with solubles (DDGS) was investigated using a stop-flow reactor system. Additionally, the catalytic effects originating from the reactor wall were also studied by means of an inert gold liner to isolate the reaction from the X22 reactor alloy. DDGS was converted into a crude bio-oil at a fixed reaction temperature (350°C), pressure (250bar) and reaction time (15min). The oil was characterized in terms of yield, char content, ash content, elemental composition, chemical composition and heating value. Neither the ZrO2 catalyst nor the reactor wall was found to have any significant effects on the yields and properties of the produced bio-oil. Consequently, ZrO2 appears to be a poor catalyst for hydrothermal liquefaction of biomass. The X22 alloy is found to be highly suitable for construction of hydrothermal liquefaction reactors.

Hydrothermal liquefaction of Chlorella pyrenoidosa for bio-oil production over Ce/HZSM-5

This paper investigated a novel hydrothermal liquefaction process of Chlorella pyrenoidosa catalyzed by Ce/HZSM-5. The chemical groups and components of the residues of C. pyrenoidosa were analyzed by Fourier transform infrared spectrometry and Gas Chromatograph-Mass Spectrometer. The crystal structure and micro surface topography of C. pyrenoidosa before and after catalytic liquefaction were characterized by X-ray diffraction and Scanning electron microscopy, respectively. The experimental results showed that the catalytic cracking effects of Ce/HZSM-5 were superior to that of HZSM-5 as a liquefaction catalyst of C. pyrenoidosa. Compared with HZSM-5, Ce/HZSM-5 has a significantly enhanced Lewis acid active center, smaller particle size, larger specific surface, and highly dispersed Ce4O7 with trivalent and tetravalent cerium in the zeolite skeleton channel that accelerate the catalytic liquefaction of C. pyrenoidosa. The rare earth modified zeolite Ce/HZSM-5 exhibits good potential and a beneficial nature for the preparation of bio-oil from microalgae with high efficiency.

Effects of solvents and catalysts in liquefaction of pinewood sawdust for the production of bio-oils

Liquefaction of biomass with proper solvents and catalysts is a promising process to produce liquid biofuels and valuable chemicals. In this study, pinewood sawdust was liquefied in the presence of various supercritical solvents (carbon dioxide, water, acetone, and ethanol) and catalysts (alkali salts and acidic zeolites). The liquid, gas and solid products were analyzed using GC–MS, FT-IR, elemental analyzer, 1H NMR, 13C NMR. The experimental results showed that both solvent and catalyst can significantly improve the liquefaction process by increasing the yield of liquid oil and suppressing the formation of solid residue. K2CO3 showed the best performance by doubling the yield of bio oil. Meanwhile, the maximum bio-oil yield (30.8 wt%) and the minimum solid residue yield (28.9 wt%) were obtained when ethanol was employed as the solvent. Solvents can also strongly affect the distribution of liquid products. 2,4,5,7-tetramethyl-phenanthrene and bis(2-ethylhexyl) phthalate were the premier compounds in liquid product as supercritical carbon dioxide is used as solvent while 2-methyl-naphthalene became the main composition when water is used as solvent.

Liquefaction of sawdust in 1-octanol using acidic ionic liquids as catalyst

Acidic ionic liquids (AILs) as a novel catalyst in biomass liquefaction can accord with the demand of green chemistry and enhance the development of biomass thermal chemical conversion. A series of AILs containing HSO4- were synthesized by the imidazolium cation functionalization and applied to the Chinese fir sawdust liquefaction in 1-octanol in this paper. The experimental results showed that the liquefaction rate was gradually improved with the AILs acidity increasing, and reached 71.5% when 1-(4-sulfobutyl)-3-methylmidazolium hydrosulfate was used as catalyst with the 6:1 mass ratio of 1-octanol to sawdust at 423K after 60 min. Lignin, hemicellulose and cellulose were orderly desquamated, and then depolymerized and liquefied with the catalyst acidity increasing in the sawdust liquefaction process. The light oil was mainly composed of the octyl ether and the octyl ester compounds, suggesting that the solvent may play an important role in producing the high octane rating biofuel.

Coliquefaction behaviours of Shenhua coal and sawdust catalysed by different catalysts

AbstractColiquefactions of a subbituminous coal and sawdust over four different coal liquefaction catalysts were studied, and the coliquefied products were characterised by elemental analysis, Fourier transform infrared spectroscopy and gel permeation chromatogram measurements. It is found that FeS+S and Co–Mo/Al2O3 catalysts have the highest catalytic activity for the liquefaction of Shenhua coal and sawdust respectively. There exists synergistic effect in the coliquefaction of Shenhua coal and sawdust, and the main synergistic interaction is reflected by the promotion of preasphaltene formation. The catalytic activities of the four catalysts in the coliquefaction are quite different from their catalytic activities in the individual liquefaction of coal and sawdust. FeS gives the lowest catalytic activity for the coal liquefaction among the four catalysts but has the highest promotion to the synergistic effect in conversion in the coliquefaction of Shenhua coal and sawdust. diminishes this synergistic ef...

Thermochemical liquefaction of rice husk for bio-oil production with sub- and supercritical ethanol as solvent

Rice husk was converted into bio-oil via thermochemical liquefaction with ethanol as solvent in an autoclave (500mL). The influences of reaction parameters on the yields of liquefaction products were investigated. Liquefaction experiments were performed at various reaction temperatures (T, 513–633K), solid–liquid ratios (R1, 5–15%), and solvent filling ratios (R2, 10–30%) with or without catalyst. Two types of catalysts were involved, including iron-based catalysts (FeSO4 and FeS) and alkali metal compounds (NaCO3 and NaOH). The dosage of catalyst (R3) was also optimized. Without catalyst, the bio-oil yields ranged from 11.8% to 24.2%, depending on T, R1 and R2. And the bio-oil yields increased firstly and then decreased with increasing T and R2, while the bio-oil yields continuously declined with increasing R1. NaOH was certified to be an ideal catalyst for rice husk liquefaction and the optimal dosage was approximately 10%. The obtained bio-oils had much higher caloric values of 20.9–24.8MJ/kg compared to 14.9MJ/kg for the crude rice husk sample. Without catalyst, the main components of bio-oil were phenolic compounds. In the case of NaOH as catalyst, long-chain alkanes were the major compositions of bio-oil.

Humic acid-Fe as catalyst for coal liquefaction

Research to increase the activity of iron based catalysts focuses on decreasing the particle size, increasing catalyst dispersion. The chelate compound of iron with humic acid (HA), which macromolecules radii can range from 6 to 50 nm, is truly in a highly dispersed state. Fe2+ or Fe3+ were dispersed finely into the HA matrix through the ion exchange with -COOH groups or chelate with carbonyl group in humic acid macromolecules. X-ray diffraction (XRD) and FT-IR spectrophotometer were used to characterize iron species before or after chelating with humic acid. The results indicate that there exist α-FeOOH, ferrihydrite and amorphous iron in HA-Fe. Most of the work has been conducted on a laboratory scale, and the results show that HA-Fe catalyst was approved for its excellent catalytic activity in coal liquefaction, and the conversion and oil yield of coal have been greatly improved.

Characterization of Fe2O3/FeOOH Catalyzed Solvolytic Liquefaction of Oil Palm Empty Fruit Bunch (EFB) Products

The addition of Fe2O3/FeOOH nanoparticles as a catalyst in solvolytic liquefaction of oil palm empty fruit bunch (EFB) could be cheaper and efficient alternative for biomass industry in Malaysia. Fe2O3/FeOOH can be found naturally in limonite ores and it is cheap, but work efficiently in catalyzing liquefaction. The purpose of this study is to understand the effects on the combination of Fe2O3/FeOOH, as the catalyst in solvolytic liquefaction of EFB. Solvolytic liquefaction of EFB fiber, with and without Fe2O3/FeOOH, was carried out in the nitrogen gas atmosphere using an autoclave. This liquefaction mainly yielded solvolytic oil, n-hexane insoluble preasphaltene and asphaltene phase (PA+A), and solid residue. The presence of catalyst has significantly increased the liquefaction yield and solvolytic oil fraction. Chemical elemental analysis has showed that the products with lower oxygen content are obtained when Fe2O3/FeOOH is used. FT-IR spectroscopy proved that the conversion of the higher molecular compound to the lower molecular compounds with larger number of functional groups has occurred. The analytical Pyrolysis-GCMS revealed the existence of lower molecular weight alcohols, ketones, phenolic and aromatic compounds.

Preparation and Catalytic Performance of Fe-Cr-Si-Pillared Montmorillonite as Coal Liquefaction Catalyst

A set of pillared montmorillonite (PILM) catalysts were prepared by exchanging Na+ with iron pillars, chromium pillars, complexes pillars of iron and chromium with different proportion, as well as complexes pillar of silica sol and iron and chromium, respectively. X-ray diffraction (XRD), X-ray fluorescence (XRF), thermogravimetry (TG) and differential thermal analysis (DTA) were used to characterize the catalysts. The XRD results reveal that Fe-Cr complexes pillared montmorillonites (Fe/Cr-PILM) have the basal spacing of about 2.04 nm after calcination at 300 °C for 2 h, while sole metal PILM have that of about 1.0 nm; in particular, the basal spacing of silica sol complexes pillared montmorillonite (Fe-Cr-Si-PILM) are expanded up to 4.33 nm. The TG-DTA results show that both Fe-Cr-PILM and Fe-Cr-Si-PILM have high thermal stability up to 640 °C. Catalytic activity of Fe/Cr-Si-PILM in Longkou lignite (LL) and ShengLi coal residue (SCR) liquefaction was studied, which showed that PILM had a good catalytic performance in coal conversion field.

Co-liquefaction of rice straw and coal using different catalysts

Co-liquefactions of a Chinese Shenfu sub-bituminous coal (SFSBC) and rice straw (RS) over four different coal liquefaction catalysts were carried out and the co-liquefied product preasphaltene (PA) was characterized by elemental analysis, FTIR and gel permeation chromatograms (GPC) measurements. It was found that the four catalysts gave different catalytic activities in the liquefaction of SFSBC and RS alone. CoMo/Al2O3 and SO42-/ZrO2 promoted the oil formation for RS liquefaction due to their solid acidic property, but FeS+S gave the highest catalytic activity for the liquefaction of SFSBC among the four catalysts used in this study. There existed a positive synergistic effect in the co-liquefaction of SFSBC and RS, and the main synergistic interaction was reflected by the promoted formation of oil and PA. The catalytic activities of the four catalysts in the co-liquefaction were quite different from their catalytic activities in the individual liquefaction of SFSBC and RS. FeS gave the lowest catalytic activity for the coal liquefaction alone among the four catalysts, but had the highest promotion to the synergistic effect in the total yield of liquefaction products in the co-liquefaction of SFSBC and RS. SO42-/ZrO2 diminished this synergistic effect for the co-liquefaction of SFSBC and RS due to its solid acidic property. It was found that the four catalysts used have higher catalytic activity for the PA, which is from coal liquefaction and converting this part of PA into AS and oil fraction. The average molecular weights of PAs from SO42-/ZrO2 and CoMo/Al2O3 catalysts were lower than those of PAs from FeS and FeS+S catalysts, suggesting that the catalytic hydrogenation activities of SO42-/ZrO2 and CoMo/Al2O3 are higher than those of FeS and FeS+S catalysts.

Synthesis and catalysis of oleic acid-coated Fe3O4 nanocrystals for direct coal liquefaction

Abstract Oleic acid-coated Fe3O4 nanocrystals have been prepared by thermal decomposition of iron–oleate complex in the presence of oleic acid. The nanocrystals were characterized by X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), transmission electron microscopy (TEM) and Fourier transform infrared spectrometry (FTIR). The results show that the oleic acid-coated Fe3O4 nanocrystals are spherical, around 15 nm in diameter. The as-synthesized Fe3O4 nanocrystals are highly effective catalysts for the direct liquefaction of Jiangjunmiao coal. With 1.5 wt.% Fe of dry and ash-free (daf) coal added as the synthesized nanocatalysts, the conversion, oil yield, and liquefaction degree reached 97.2, 86.5, and 92.0%, respectively.

An overview of solid–liquid separation of residues from coal liquefaction processes

AbstractDirect coal liquefaction process typically produces mixed oils (60%) and gases (15%). The remainder is a high‐boiling viscous residue that contains oils, asphaltenes, unreacted coal, mineral matter and potentially valuable liquefaction catalyst. Effective separation of the components of the residue stream is important to the economic and environmental performance of the process. Solid–liquid separation technologies, such as filtration, hydrocyclones, centrifugation, critical solvent deashing and distillation have been reviewed in relation to their use in coal liquefaction processes. Individual operations used have not been completely satisfactory, and a better overall result is obtained when they are used in combination. © 2012 Canadian Society for Chemical Engineering

SO3H-functionalized ionic liquid: Efficient catalyst for bagasse liquefaction

Liquefaction is a process for the production of biofuel or value-added biochemicals from non-food biomass. SO3H-, COOH-functionalized and HSO4-paired imidazolium ionic liquids were shown to be efficient catalysts for bagasse liquefaction in hot compressed water. Using SO3H-functionalized ionic liquid, 96.1% of bagasse was liquefied and 50.6% was selectively converted to low-boiling biochemicals at 543K. The degree of liquefaction and selectivity for low-boiling products increased and the average molecular weight of the tetrahydrofuran soluble products decreased with increasing acidic strength of ionic liquids. Analysis of products and comparative characterization of raw materials and residues suggested that both catalytic liquefaction and hydrolysis processes contribute to the high conversion of bagasse. A possible liquefaction mechanism based on the generation of 3-cyclohexyl-1-propanol, one of the main products, is proposed.

Liquefactions of peat in supercritical water with a novel iron catalyst

Raw iron ore has been investigated for use as a catalyst in direct liquefaction of peat into bio-crude by supercritical water treatment. The liquefaction treatments were conducted at temperatures from 350 °C to 500 °C for a residence time from 10 min to 4 h. The supercritical water treatment of peat with the iron ore generally resulted in 19–40 wt% yield of heavy oil (HO) that has a higher heating value (HHV) of 30–37 MJ/kg. An increase in the operating temperature generally increased gas yield and decreased oil and char yields, while a maximum HO formation was observed at around 400 °C. At 400 °C for a residence time of 2 h, the addition of the raw iron ore in the operation produced HO at a very high yield of about 40 wt%, nearly doubling that of the treatment without catalyst. An increase of water-to-peat ratio led to enhanced formation of HO products, accompanied by a decrease in gas or char yield. The optimal reaction time appeared to be 2 h for the maximum HO production, and a longer residence time than 2 h generally led to a decrease in HO yield but an increase in gas yield. Compared with the raw iron ore, its H 2-reduced form and two synthesized iron-based catalysts (FeOOH and Fe 2O 3) all showed a lower activity for HO production. Some conventional biomass liquefaction catalysts (i.e., KOH, FeCl 3 and FeSO 4) showed negligible or even negative effects on the HO yield, while these catalysts were found very active for promoting the gas yields and hydrogen formation.

A Study on the Hydrotreating of Coal Hydroliquefaction Residue and its Kinetics

Hydro-conversion of coal hydroliquefaction residue obtained from a 6t/day pilot plant of Shenhua Group in Shanghai was carried out under the hydrotreating condition. The coal hydroliquefaction residue and its product were extracted in sequence with n-hexane, toluene and tetrahydrofuran in a Soxhlet apparatus. The n-hexane soluble fractions increased with the increase of reaction temperature and time. Its amount increased from 14.14% to a maximum of 40.86% under the conditions of 470 °C and 30 min, which meant that moderate extension of coal residence time in the coal hydroliquefaction reactor is beneficial to the increase of oil yield. A 4-lumped kinetic model of coal hydroliquefaction residue hydro-conversion was performed using solubility-based lumped fractions. In the model, the tetrahydrofuran insoluble fractions were classified into two parts: easily reactive part and unreactive part. The kinetic parameters were estimated by a fourth-order Runge-Kutta method and a nonlinear least squares method, and the apparent activation energies were calculated according to the Arrhenius Equation. A large quantity of total catalyst consisting of remained liquefaction catalyst, part of the mineral from raw coal and additive Fe-based catalyst could considerably reduce the apparent activation energy of hydro-conversion for the toluene insoluble/tetrahydrofuran insoluble fractions to 36.79 kJ•mol-1. The calculated values of the model coincided well with the experimental values.