Low energy consumption and high quality bio-fuels production via in-situ fast pyrolysis of reed straw by adding metallic particles in an induction heating reactor

An in-situ fast pyrolysis of biomass by adding metallic particles in an induction heating reactor was proposed to produce high quality bio-fuels. After adding metallic particles into biomass, the times required to reach complete pyrolysis during reed straw pyrolysis process were significantly reduced up to 28.9%. The yields of combustible gas and bio-oil products were significantly increased. Furthermore, higher-quality combustible gas and bio-oil products were obtained with the LHV of gas products and HHV of bio-oil (dry basis) increased by 14.2%–19.1% and 4.16%–16.35%, respectively, under 400–600 °C. The lower oxygen content and higher yields of aromatics, alkenes and alkanes contents in bio-oil were obtained after metallic particles addition. More importantly, up to 26.5% of the total energy consumption during pyrolysis process was reduced after adding metallic particles into biomass in an induction heating reactor. The results indicate that adding metallic particles into biomass in an induction heating reactor can significantly enhance the heat transfer, decomposition reaction intensity and energy utilization efficiency of biomass pyrolysis process with lower energy consumption and higher-quality bio-fuel production.     

Oxidative pyrolysis of kraft lignin in a bubbling fluidized bed reactor with air

Fast pyrolysis of kraft lignin with partial (air) oxidation was studied in a bubbling fluidized bed reactor at reaction temperatures of 773 and 823 K. The bio-oil vapors were fractionated using a series of three condensers maintained at desired temperatures, providing a dry bio-oil with less than 1% water and over 96% of the total bio-oil energy.Oxygen feed was varied to study its effect on yield, composition, and energy recovery in the gas, char and oil products. The addition of oxygen to the pyrolysis process increased the production of gases such as CO and CO₂. It also changed the dry bio-oil properties, reducing its heating value, increasing its oxygen content, reducing its average molecular weight and tar concentration, while increasing its phenolics concentration. The lower reaction temperature of 773 K was preferred for both dry bio-oil yield and quality.Autothermal operation of the pyrolysis process was achieved with an oxygen feed of 72 or 54 g per kg of biomass at the reaction temperatures of 773 and 823 K, respectively. Autothermal operation reduced both yield and total energy content of the dry bio-oil, with relative reductions of 24 and 20% for the yield, 28 and 23% for the energy content, at 773 and 823 K.     

Hydrothermal liquefaction of macroalgae: Influence of zeolites based catalyst on products

Hydrothermal liquefaction (HTL) of Ulva prolifera macroalgae (UP) was carried out in the presence of three zeolites based catalysts (ZSM-5, Y-Zeolite and Mordenite) with the different weight percentage (10–20 wt%) at 260–300 °C for 15–45 min. A comparison between non-catalytic and catalytic behavior of ZSM-5, Y-Zeolite, and Mordenite in the conversion of Ulva prolifera showed that is affected by properties of zeolites. Maximum bio-oil yield for non-catalytic liquefaction was 16.6 wt% at 280 °C for 15 min. The bio-oil yield increased to 29.3 wt% with ZSM-5 catalyst (15.0 wt%) at 280 °C. The chemical components and functional groups present in the bio-oils are identified by GC-MS, FT-IR, ¹H-NMR, and elemental analysis techniques. Higher heating value (HHV) of bio-oil (32.2–34.8 MJ/kg) obtained when catalyst was used compared to the non-catalytic reaction (21.2 MJ/kg). The higher de-oxygenation occurred in the case of ZSM-5 catalytic liquefaction reaction compared to the other catalyst such as Y-zeolite and mordenite. The maximum percentage of the aromatic proton was observed in bio-oil of ZSM-5 (29.7%) catalyzed reaction and minimum (1.4%) was observed in the non-catalyst reaction bio-oil. The use of zeolites catalyst during the liquefaction, the oxygen content in the bio-oil reduced to 17.7%. Aqueous phase analysis exposed that presence of valuables nutrients.     

Upgraded biofuel from residue biomass by Thermo-Catalytic Reforming and hydrodeoxygenation

Research is focused on the utilisation of waste or residue biomass for bioenergy conversion. A promising conversion technology for the production of liquid biofuels from residue biomass is a process called Thermo-Catalytic Reforming (TCR^®​) which is a combination of prior thermal treatment of the biomass at mild temperatures (intermediate pyrolysis) followed by a second catalytic treatment step at elevated temperatures (reforming). This article focuses on the conversion of TCR^® liquids from digestate as a feedstock for subsequent hydrocarbon production. The generated bio-oil showed a lower heating value of 34.0 MJ kg⁻¹ with an oxygen content of 7.0% and a water content of 2.2%. The bio-oil was hydrodeoxygenated using an industrial NiMo–Al₂O₃ catalyst at temperatures of 503 K–643 K and a pressure of 14 MPa. The hydrodeoxygenated bio-oil reached a lower heating value of 42.3 MJ kg⁻¹ with an oxygen content below 0.8 mg kg⁻¹ and water content of 30 ppm. Product yields and catalyst life give confidence that upgrading of the TCR^®​ bio-oil offers a suitable option to meet the high standards of common fuels.     

Non-catalytic and catalytic pyrolysis of Ulva prolifera macroalgae for production of quality bio-oil

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.     

Microalgae as a renewable fuel source: Fast pyrolysis of Scenedesmus sp.

Herein we report the fast pyrolysis of dried, ground Scenedesmus sp. at two different reactor scales. Pyrolysis was performed at 480 °C and 1 bar in both an isothermal spouted bed reactor and a dynamic pyrolysis-GC/MS unit, each with 2 s vapor residence times. Bio-oil products were characterized on the basis of GC-MS, simulated distillation GC, elemental analysis, calorific content and total acid number. The ratio of crude oil: char obtained from the spouted bed reactor was 3.76 by weight, the average calorific content of the oil being 18.4 MJ/kg. The average total acid number (68 mg KOH/g) was lower than typical bio-oil produced via wood pyrolysis. Simulated distillation results indicated that a significant proportion of the oil corresponded to the boiling range typical for heavy gas oil (343 °C–524 °C). Elemental analysis showed the oil contained an average of 27.6 wt.% oxygen and 8.6 wt.% nitrogen, the relatively high nitrogen content being a consequence of the high protein content of the algae. According to GC-MS data, the oil consisted of various hydrocarbons as well as oxygenated and nitrogenous species, including indoles, fatty acids and amides. Pyrolysis-GC-MS was also performed on Scenedesmus sp. in order to provide insights into the nature of the primary pyrolysis products.     

Distributed production of hydrogen by auto-thermal reforming of fast pyrolysis bio-oil

We demonstrated an auto-thermal reforming process for producing hydrogen from biomass pyrolysis liquids. Using a noble metal catalyst (0.5% Pt/Al₂O₃ from BASF) at a methane-equivalent space velocity of around 2000 h⁻¹, a reformer temperature of 800 °C–850 °C, a steam-to-carbon ratio of 2.8–4.0, and an oxygen-to-carbon ratio of 0.9–1.1, we produced 9–11 g of hydrogen per 100 g of fast pyrolysis bio-oil, which corresponds to 70%–83% of the stoichiometric potential. The elemental composition of bio-oil and the bio-oil carbon-to-gas conversion, which ranged from 70% to 89%, had the most significant impact on the yield of hydrogen. Because of incomplete volatility the remaining 11%–30% of bio-oil carbon formed deposits in the evaporator. Assuming the same process efficiency as that in the laboratory unit, the cost of hydrogen production in a 1500 kg/day plant was estimated at $4.26/kg with the feedstock, fast pyrolysis bio-oil, contributing 56.3% of the production cost.     

Impact of a pressurized hot water treatment on the quality of bio-oil produced from aspen

The bio-oil produced by fast pyrolysis is a genuine alternative to fossil resources. However an improvement of its quality is required in order to improve its application.To upgrade the quality of bio-oil, Pressurized Hot Water Treatment (PHWT) has been applied on trembling aspen whole wood chips prior to fast pyrolysis process. The pyrolysis was then performed in an auger reactor at the temperature of 723 K. The effects of PHWT on yields, physicochemical properties, and composition of bio-oils were investigated.Although PHWT does not seem to influence the bio-oil yield, which remains around 56% for both untreated and pre-treated wood, it does improve its quality. The main effect of pre-treatment is the lower water content of the oil obtained from pre-treated wood, which is thus meeting the requirements of ASTM D7544 Standard. Moreover, PHWT appeared to favor the levoglucosan production and to decrease the syringol derivatives content of the bio-oil. The elementary composition revealed an increase of the C/O ratio when the biomass was pre-treated. This is in agreement with the heating value of bio-oil from pre-treated biomass which was found to be higher than that of bio-oil from untreated biomass.     

Effect of fractional condensers on characteristics,compounds distribution and phenols selection of bio-oil from pine sawdust fast pyrolysis

Bio-oil is a multicomponent mixture of more than 400 types of organic compounds, with high water content. Fractionation of bio-oil may be a more efficient approach for primary separation of bio-oil. In this work, to better understand the effect of fractional condensers on bio-oil yield, physicochemical characteristics, compounds distribution and phenols selection during biomass fast pyrolysis process, a semi-automatic controlled fluidized bed reactor biomass fast pyrolysis system with four-stage condensers was developed. Average temperatures of Condensers 1, 2, 3, 4 were 32.39 °C, 26.74 °C, 24.06 °C and 23.68 °C, respectively. And the bio-oil yields of Condenser 1, 2, 3, and 4 were 26.82%, 7.31%, 1.48% and 9.69%, respectively. Bio-oil collected from Condenser 4 had the lowest water content (9.68 wt%), the lowest acidity (pH = 3.67), and the highest HHV (29.2 MJ/kg). The highest relative contents of compounds collected from Condenser 1, 2, 3 and 4 were 1-(4-hydroxy-3-methoxyphenyl)-2-Propanone (6.95%), trans-Isoeugenol (6.63%), Creosol (5.28%), and trans-Isoeugenol (6.69%), respectively. Fractional condensers affected the compounds distribution, but it has a stronger effect on relative heavy compounds (molar mass > 250) and a weaker effect on relative light compounds (molar mass < 200). Fractional condensers were more conducive to the selection of phenols with relative yield of more than 30%. Phenols, acids and furfurans tended to distribute at higher temperature, while alcohols, ethers and hydrocarbons tended to distribute at relative lower temperature, but the difference was small. The research has provided a reference for the production of bio-oil.     

Effects of ash removal by agitated aqueous washing and sedimentation on the physico-chemical characteristics and fast pyrolysis of trommel fines

A pre-treated trommel fines feedstock (DPT) with 35.1 wt% ash content and particle size range of 0.5–2 mm was processed through two (100% distilled water and 1% surfactant in distilled water) aqueous agitated washing and sedimentation procedures for ash reduction prior to fast pyrolysis in a bubbling fluidized bed reactor. The washing process led to more than 36% reduction in the ash/inorganic contents of the DPT feedstock and yielded about 78 wt% of organic-rich feedstocks denoted as WPT1 and WPT2. Characterisation and fast pyrolysis of all three feedstocks was carried out to evaluate the effect of the washing process on their physico-chemical characteristics and yields of fast pyrolysis products. Results showed that the ash reduction led to increase in the volatile matter contents of the washed feedstocks by 20%, while reducing nitrogen contents. In addition, fast pyrolysis of the feedstocks showed improved yield of liquid and gas products, with a dramatic reduction of reaction water, indicating that the ash removal reduced the catalytic effect of the ash on water formation during the fast pyrolysis process. The major organic compounds in the liquid products included phenols and furans from biogenic fraction of the feedstock as well as aromatic hydrocarbons such as those obtained from pyrolysis of plastics. More importantly, the overall energy yields from the fast pyrolysis process increased by over 35% after washing the feedstock, with washing with only distilled water alone giving the highest energy yield of 93%. Hence, coupling the water-washing ash reduction process with fast pyrolysis appeared to be a suitable technology for valorising feedstocks with high ash contents such as trommel fines for energy and chemicals.     

Potentiality of combined catalyst for high quality bio-oil production from catalytic pyrolysis of pinewood using an analytical Py-GC/MS and fixed bed reactor

The aim of this study was to investigate the potential of combined catalyst (ZSM-5 and CaO) for high quality bio-oil production from the catalytic pyrolysis of pinewood sawdust that was performed in Py-GC/MS and fixed bed reactor at 500 °C. In Py-GC/MS, the maximum yield of aromatic hydrocarbon was 36 wt% at biomass to combined catalyst ratio of 1:4 where the mass ratio of ZSM-5 to CaO in the combined catalyst was 4:1. An increasing trend of phenolic compounds was observed with an increasing amount of CaO, whereas the highest yield of phenolic compounds (31 wt%) was recorded at biomass to combined catalyst ratio of 1:4 (ZSM-5: CaO - 4:1). Large molecule compounds could be found to crack into small molecules over CaO and then undergo further reactions over zeolites. The water content, higher heating value, and acidity of bio-oil from the fixed bed reactor were 21%, 24.27 MJkg⁻¹, and 4.1, respectively, which indicates that the quality of obtained bio-oil meets the liquid biofuel standard ASTM D7544-12 for grade G biofuel. This research will provide a significant reference to produce a high-quality bio-oil from the catalytic pyrolysis of woody biomass over the combined catalyst at different mass ratios of biomass to catalyst.     

Utilization possibilities of palm shell as a source of biomass energy in Malaysia by producing bio-oil in pyrolysis process

Agriculture residues such as palm shell are one of the biomass categories that can be utilized for conversion to bio-oil by using pyrolysis process. Palm shells were pyrolyzed in a fluidized-bed reactor at 400, 500, 600, 700 and 800 °C with N₂ as carrier gas at flow rate 1, 2, 3, 4 and 5 L/min. The objective of the present work is to determine the effects of temperature, flow rate of N₂, particle size and reaction time on the optimization of production of renewable bio-oil from palm shell. According to this study the maximum yield of bio-oil (47.3 wt%) can be obtained, working at the medium level for the operation temperature (500 °C) and 2 L/min of N₂ flow rate at 60 min reaction time. Temperature is the most important factor, having a significant positive effect on yield product of bio-oil. The oil was characterized by Fourier Transform infra-red (FT-IR) spectroscopy and gas chromatography/mass spectrometry (GC-MS) techniques.     

Catalytic pyrolysis of distillers dried grain with solubles: An attempt towards obtaining value-added products

Catalytic pyrolysis of distillers dried grain with solubles by nickel-based catalysts was performed. The effects of pyrolysis temperature, catalytic carrier and components on the products were investigated. The catalysts were characterized with NH₃-TPD, XPS, H₂-TPR. The average higher heating value (HHV) of the bio-oil was about 61% of the HHV of gasoline. GC/MS analysis indicated that the bio-oil contained some value-added compounds such as 2-furaldehyde, 2-furanmethanol, 3-pyridinol, dodecane, etc. The pyrolysis gas rich in hydrogen was obtained under the direct catalysis of nickel-based catalysts. For Ni–Pd-γ-Al₂O₃, the volume percentage of hydrogen in gas reached 55.6 vol.% at 500 °C, revealing that there was a strong synergistic effect between Ni and Pd. According to the experimental results the possible mechanism was proposed. It was considered that the metal species over catalyst was the most important factor for its performance, and the influence from its Lewis acidity could not be ignored.     

Comparison of pyrolysis and hydrothermal liquefaction of Chlamydomonas reinhardtii. Growth studies on the recovered hydrothermal aqueous phase

The production of bio-oil by pyrolysis with a high heating rate (500 K s⁻¹) and hydrothermal liquefaction (HTL) of Chlamydomonas reinhardtii was compared. HTL led to bio-oil yield decreasing from 67% mass fraction at 220 °C to 59% mass fraction at 310 °C whereas the bio-oil yield increased from 53% mass fraction at 400 °C to 60% mass fraction at 550 °C for pyrolysis. Energy ratios (energy produced in the form of bio-oil divided by the energy content of the initial microalgae) between 66% at 220 °C and 90% at 310 °C in HTL were obtained whereas it was in the range 73–83% at 400–550 °C for pyrolysis. The Higher Heating Value of the HTL bio-oil was increasing with the temperature while it was constant for pyrolysis. Microalgae cultivation in aqueous phase produced by HTL was also investigated and showed promising results.     

Utilization possibilities of Albizia amara as a source of biomass energy for bio-oil in pyrolysis process

Pyrolysis is one of the potential routes to harmless energy and useful chemicals from biomass. The pyrolysis of Albizia amara was studied for determining the main characteristics and quantities of liquid products. Particular investigated process variables were temperature from 350 to 550°C, particle size from 0.6 to 1.25 mm, and heating rate from 10 to 30 °C/min. The maximum bio-oil yield of 48.5 wt% at the pyrolysis temperature of 450°C was obtained at the particle size of 1.0 mm and at the heating rate of 30 °C/min. The bio-oil product was analyzed for physical, elemental, and chemical composition using Fourier transform infrared spectroscopy and gas chromatography spectroscopy. The bio-oil contains mostly phenols, alkanes, alkenes, saturated fatty acids and their derivatives. According to the experimental results, the pyrolysis bio-oil can be used as low-grade fuel having heating value of 18.63 MJ/kg and feedstock for chemical industries.     

Biochar from microwave pyrolysis of biomass: A review

Microwave based technology is an alternative heating method and has already been successfully used in biomass pyrolysis for biochar and biofuel production thanks to its fast, volumetric, selective and efficient heating. Previous review mainly focused on production and analysis of bio-oil and gas instead of biochar. The current paper provides a review of microwave-assisted pyrolysis (MWP) of biomass and its biochar characteristics, including product distribution and biochar yield, biochar properties, microwave absorbers (MWAs) and catalysts commonly used in MWP, as well as comparison of biochar derived from MWP and conventional pyrolysis (CP). MWAs not only absorb microwave energy, they also act as catalysts to interact with gas, vapor and solids in the reactor, adjusting the product distribution and quality of products. It was reported for MWP that the highest biochar yield was >60 wt% and the maximum BET surface area was about 450–800 m²/g. Technology status and economics of MWP of biomass in China were briefly introduced. The Optimization of yield and quality of biochar strongly depends on feedstock properties, reactor types, operating parameters, MWAs and catalysts added to the system.     

Catalytic conversion of fast pyrolysis oil to hydrocarbon fuels over HZSM-5 in a dual reactor system

The catalytic conversion of fast pyrolysis bio-oil to hydrocarbon fuels was studied over HZSM-5 at atmospheric pressure. Experiments were conducted in a dual reactor system having two reactors in series. The temperatures in these reactors were in the range 340–400°C (first reactor) and 350–450°C (second reactor). The bio-oil was co-processed with tetralin in all the runs. The objective was to maximize the organic distillate product with a high concentration of aromatic hydrocarbons. The maximum amount of organic distillate in the effluent from the second reactor was 21 wt% of the bio-oil feed and the highest concentration of aromatic hydrocarbons was 76 wt% of the distillate. The dual reactor system was particularly beneficial when the temperature in the first reactor was low. Thus, with the first reactor at 340°C, the yields of organic distillate and aromatic hydrocarbons were 15–16 wt% and 8–11 wt% of wood, respectively, which are nearly two-fold compared to those from a single reactor system operated at 340°C (7.8 wt% and 4.8 wt%). Under the above conditions, the coke plus char yields were 25–26 wt% of wood which are up to 10 wt% lower than from the single reactor system at 340°C (29 wt%).     

Pyrolysis of Alternanthera philoxeroides (alligator weed): Effect of pyrolysis parameter on product yield and characterization of liquid product and bio char

In the present work, fast pyrolysis of Alternanthera philoxeroides was evaluated with a focus to study the chemical and physical characteristics of bio-oil produced and to determine its practicability as a transportation fuel. Pyrolysis of A.philoxeroides was conducted inside a semi batch quartz glass reactor to determine the effect of different operating conditions on the pyrolysis product yield. The thermal pyrolysis of A. philoxeroides were performed at a temperature range from 350 to 550 °C at a constant heating rate of 25 °C/min & under nitrogen atmosphere at a flow rate of 0.1 L/min, which yielded a total 40.10 wt.% of bio-oil at 450 °C. Later, some more sets of experiments were also performed to see the effect on pyrolysis product yield with change in operating conditions like varying heating rates (50 °C/min, 75 °C/min & 100 °C/min) and different flow rates of nitrogen (0.2, 0.3, 0.4 & 0.5 L/min). The yield of bio-oil during different heating rate (25, 50, 75 and 100 °C/min) was found to be more (43.15 wt.%) at a constant heating rate of 50 °C/min with 0.2 L/min N₂ gas flow rate and at a fixed pyrolysis temperature of 450 °C. The High Heating Value (HHV) value of bio-oil (8.88 MJ/kg) was very less due to presence of oxygen in the biomass. However, the high heating value of bio-char (20.41 MJ/kg) was more, and has the potential to be used as a solid fuel. The thermal degradation of A. philoxeroides was studied in TGA under inert atmosphere. The characterization of bio-oil was done by elemental analyser (CHNS/O analyser), FT-IR, & GC/MS. The char was characterized by elemental analyser (CHNS/O analysis), SEM, BET and FT-IR techniques. The chemical characterization showed that the bio-oil could be used as a transportation fuel if upgraded or blended with other fuels. The bio-oil can also be used as feedstock for different chemicals. The bio-char obtained from A. philoxeroides can be used for adsorption purposes because of its high surface area.     

生物质裂解油催化裂解精制机理研究(Ⅰ)——生物质裂解油及其催化裂解精制油的物性及组成

通过生物质裂解油和催化裂解精制油的物性和化学分析显示催化裂解精制油的密度、粘度、水含量较生物质裂解油明显降低,而pH值和热值明显提高。催化裂解精制油的碳含量较生物裂解油增加,氧含量降低。催化裂解精制油中的酸、醛、酮、糖和醇含量明显降低,酚和芳烃含量明显增加。说明经过催化裂解精制后的精制油的品质较精制前的生物裂解油明显提高。     

Bio-oil production from cotton stalk

Cotton stalk was fast pyrolyzed at temperatures between 480 °C and 530 °C in a fluidized bed, and the main product of bio-oil is obtained. The experimental result shows that the highest bio-oil yield of 55 wt% was obtained at 510 °C for cotton stalk. The chemical composition of the bio-oil acquired was analyzed by GC–MS, and its heat value, stability, miscibility and corrosion characteristics were determined. These results showed that the bio-oil obtained can be directly used as a fuel oil for combustion in a boiler or a furnace without any upgrading. Alternatively, the fuel can be refined to be used by vehicles. Furthermore, the energy performance of the pyrolysis process was analyzed. In the pyrolysis system used in our experiment, some improvements to former pyrolysis systems are done. Two screw feeders were used to prevent jamming the feeding system, and the condenser is equipped with some nozzles and a heat exchanger to cool quickly the cleaned hot gas into bio-oil.