Optimization of process parameters and catalytic pyrolysis of Cascabela thevetia seeds over low-cost catalysts towards renewable fuel production

The present study deals with the optimization of process parameters and thermocatalytic pyrolysis of Cascabela thevetia (CT) seeds in a semi-batch cylindrical-shaped reactor. Response surface methodology (RSM) was employed for the optimization of process variables, while commercial catalysts CaO and Al₂O₃ were used for catalytic pyrolysis. From results, it was concluded that 525 °C temperature, 75 °C min⁻¹ heating rate, and 75 mL min⁻¹ flow of nitrogen yielded maximum pyrolytic liquid (45.26 wt%) while with the attendance of catalysts at 20 wt% increased the yield of pyrolytic liquid (49.12 wt% and 46.87 wt% for CaO and Al₂O₃ respectively). Optimization outcomes displayed that linear and quadratic terms of utilized factors were more noteworthy while interaction effects between the factors were not significant. Further, characterization of pyrolytic oil established that utilization of catalysts expressively enhanced its properties by reducing viscosity and boosted the calorific value. FTIR examination of pyrolytic oil showed that the attendance of phenols, ethers, alcohols, ketones, alkanes, acids, etc., while ¹H NMR results supported the FTIR results. GC-MS analysis showed a substantial reduction of phenols and oxygen-rich products and boost the development of alcohol and aldehydes in pyrolytic oil with the introduction of catalysts. These parameters indicate improved properties of pyrolytic oil, which intensified its bioenergy capabilities.     

Experimental study of the pyrolysis of waste bitumen for oil production

This work focuses on bitumen slow pyrolysis. Mass and energy yields of oil, solid and gas were obtained from pyrolysis experiments using a semi-batch reactor in a nitrogen atmosphere, under three non-isothermal conditions (maximum temperature: 450 °C, 500 °C and 550 °C). The effect of temperature on the product yields was discussed. The gas compositions were analysed using gas chromatography (GC) and the heating value of oil and solid residue was also measured. Using a thermo-gravimetric analyser, kinetic parameters were evaluated through Ozawa-Flynn-Wall (OFW) method. Results showed that oil yield is maximum at 500 °C (50%). Moreover, gas yield increased with increasing pyrolysis temperature from 18% to 36%. On the other hand, solid yield showed an opposite trend: it decreased from 39% to 32%. As regard energy yields, they showed a similar trend with the mass ones. H_2, CH₄, C₂H₄, C₂H₆ and C₃H₈ are the main components of the produced gas phase. It has been noticed that the recovery of bitumen to liquid oil through pyrolysis process had a great potential since the oil produced had high calorific value comparable with commercial fuels.     

Promotion of bio oil,H2 gas from the pyrolysis of rice husk assisted with nano silver catalyst and utilization of bio oil blend in CI engine

This paper reports on the pyrolytic distillation of rice husk with catalyst and its influence on both condensable and non-condensable volatiles. The catalyst used for pyrolysis was nano sized silver particles obtained through chemical reduction method. The structural features of the nano silver particles were explored through X-ray diffraction (XRD) and Field Emission Scanning Electron Microscope (FESEM) with Energy-dispersive-X-ray spectroscope (EDX), and the size of the nano particles was confirmed as 90 nm. After intimately mixing the rice husk (30 g) with the catalyst, the pyrolysis at various temperatures (400 °C, 450 °C, 500 °C, 550 °C) was performed. The products obtained during catalytic pyrolysis like gaseous fuel, bio oil, and bio char were separately collected and characterized through Gas Chromatography-Mass Spectrometer (GC-MS) and Inductively Coupled Plasma – Optical Emission Spectrometer (ICP-OES). About 50% of the solid biomass was converted into more useful liquid and gaseous fuel. It was noticed that during catalytic pyrolysis, the quantity of H₂ obtained was more (19.12%) in contrast to thermal pyrolysis and could be attributable to the influence of silver nano particles towards the enhancement in hydrogen gas production. The liquid hydrocarbon obtained during the catalytic distillation was blended with diesel in the ratio 20:80 in the compression ignition (CI) engine. The quality of the blended bio oil was assessed from brake thermal efficiency (BTE), brake specific fuel consumption (BSFC) and emission of nitrogen oxides (NO_X), carbon monoxide (CO) and unburnt hydrocarbon (UHC). At full load, the diesel fuel emitted 1780 ppm of NO_x while the diesel blended with bio oil emitted only 1510 ppm which was 15.17% less than the diesel oil which proved its eco-friendly nature. In future, the bio oil obtained from catalytic pyrolysis can be used as a blend for diesel oil, since it reduces NO_x emission and replaces 20% of diesel oil.     

Effect of temperature on the fast pyrolysis of organic-acid leached pinewood; the potential of low temperature pyrolysis

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.     

Influence of reaction conditions on bio-oil production from pyrolysis of construction waste wood

The pyrolysis characteristics of construction waste wood were investigated for conversion into renewable liquid fuels. The activation energy of pyrolysis derived from thermogravimetric analysis increased gradually with temperature, from 149.41 kJ/mol to 590.22 kJ/mol, as the decomposition of cellulose and hemicellulose was completed and only lignin remained to be decomposed slowly. The yield and properties of pyrolysis oil were studied using two types of reactors, a batch reactor and a fluidized-bed reactor, for a temperature range of 400–550 °C. While both reactors revealed the maximum oil yield at 500 °C, the fluidized-bed reactor consistently gave larger and less temperature-dependent oil yields than the batch reactor. This type of reactor also reduced the moisture content of the oil and improved the oil quality by minimizing the secondary condensation and dehydration. The oil from the fluidized-bed reactor resulted in a larger phenolic content than from the batch reactor, indicating more effective decomposition of lignin. The catalytic pyrolysis over HZSM-5 in the batch reactor increased the proportion of light phenolics and aromatics, which was helpful in upgrading the oil quality.     

Experimental investigation of the pyrolysis of biomass to produce green fuels

This work aims to utilise the experimental approach to perform the analysis of three-biomass feed stocks – bamboo, mustard and camellia and to provide insight into the operation and design of pyrolysis processes. Experiments on biomass fast pyrolysis were performed in a fixed bed (tubular) reactor at a temperature of 500°C and a residence time of 2?min under the constant flow of nitrogen. The analysis of pyrolysis gases and bio oil produced by pyrolysis was done using GC-MS and GC-TCD. Hydrous pyrolysis of biomasses was performed in a high-pressure autoclave for the temperature range 250–400°C and at a pressure of 20?bar with 30?min of residence time. Experiments were conducted both with and without the use of a catalyst. The pyrolysis vapour is made to pass through the catalyst bed of ZSM-5 (Si/Al?=?35). The results for all the biomass samples are then compared.     

Study of bio-oil and bio-char production from algae by slow pyrolysis

This study examined bio-oil and bio-char fuel produced from Spirulina Sp. by slow pyrolysis. A thermogravimetric analyser (TGA) was used to investigate the pyrolytic characteristics and essential components of algae. It was found that the temperature for the maximum degradation, 322 °C, is lower than that of other biomass. With our fixed-bed reactor, 125 g of dried Spirulina Sp. algae was fed under a nitrogen atmosphere until the temperature reached a set temperature between 450 and 600 °C. It was found that the suitable temperature to obtain bio-char and bio-oil were at approximately 500 and 550 °C respectively. The bio-oil components were identified by a gas chromatography/mass spectrometry (GC–MS). The saturated functional carbon of the bio-oil was in a range of heavy naphtha, kerosene and diesel oil. The energy consumption ratio (ECR) of bio-oil and bio-char was calculated, and the net energy output was positive. The ECR had an average value of 0.49.     

Valorisation of lignocellulosic biomass investigating different pyrolysis temperatures

Presently, sugarcane bagasse (SB) and oat hulls (OH) have a distinctive potential as a renewable source of biomass, due to its global availability, which is advantageous for producing liquid and gaseous fuels by thermochemical processes. Thermo-Catalytic Reforming (TCR) is a pyrolysis based technology for generating energy vectors (char, bio-oil and syngas) from biomass wastes. This work aims to study the conversion of SB and OH into fuels, using TCR in a 2 kg/h continuous pilot-scale reactor at different pyrolysis temperatures. The pyrolysis temperatures were studied at 400, 450 and 500 °C, while the subsequent reforming temperature remained constant at 500 °C. The bio-oil contained the highest calorific value of 33.4 and 33.5 MJ/kg for SB and OH, respectively at 500 °C pyrolysis temperature, which represented a notable increase compared to the raw material calorific value of SB and OH (16.4 and 16.0 MJ/kg, respectively), this was the result of deoxygenation reactions occurring. Furthermore, the increment of the pyrolysis temperature improved the water content, total acid number (TAN), viscosity and density of the bio-oil. The syngas and the biochar properties did not change significantly with the increase of the pyrolysis temperature. In order to use TCR bio-oil as an engine fuel, it is necessary to carry out some upgrading treatments; or blend it with fossil fuels if it is to be used as a transportation fuel. Overall, TCR is a promising future route for the valorisation of lignocellulosic residues to produce energy vectors.     

Potentiality of “orujillo” (olive oil solid waste) to produce hydrogen by means of pyrolysis

The extraction of olive oil generates great amounts of solid waste and wastewater. The objective of this work is to evaluate the potentiality of slow pyrolysis of the solid oil waste, known as “orujillo”, to produce hydrogen rich gases. The effect of temperature and of different treatments of pyrolysis vapors on the yield and composition of the gases has been experimentally studied. “Orujillo” was pyrolyzed at 500 °C and 700 °C, and the pyrolysis vapors produced were directly fed to a second reactor where they were treated at 800 °C in different ways: just thermally, thermally treated through a refractory alumina bed and thermo-catalytically treated through a three layer bed (alumina + SiC mixed with Ni catalyst + alumina). The catalyst used was a commercial prereduced nickel-catalyst which contains 44 wt% Ni over calcium aluminate support (CaO/Al₂O₃). Concerning the effect of temperature, it has been proved that the raise in temperature leads to a decrease in the liquid yields and an increase in the gas yields, as well as to an increase in H₂ and a decrease in CO₂ content of the gases. With respect to the vapors treatments it has been observed that as a general rule any of the treatments reduces liquid and increases gas yields, and concerning gas composition, H₂ content increases, CO slightly increases and CO₂ decreases. These effects are more pronounced when the Ni-catalyst is used. With the Ni-catalyst about 50 wt% gas yield is obtained, with ≈ 50 vol% H₂ both at 500 and at 700 °C.     

Thermal and geochemical characterization of Lokpanta oil shales,Nigeria

Thermal decomposition of Lokpanta oil shale from Nigeria was studied by non-isothermal thermogravimetry (TG) and differential thermal analysis (DTA). The experiments were performed in an inert environment with a temperature range of 25 to 600 °C. The geochemical characteristics of the oil shale were also investigated by Rock Eval. pyrolysis. Thermal breakdown of the kerogen content of the oil shale takes place mainly at the temperature range of 300 to 570 °C. The estimated decomposable kerogen content of the oil shale ranges from 4.55 to 9.64 wt.%. The activation energies of the pyrolysis process vary from 73.2 to 75.0 kJ/mol. The DTA data reveals the exothermic nature of the decomposition process. The results from the geochemical analysis indicate that the oil shale contains sufficient, good quality kerogen to generate both oil and gas upon pyrolysis.     

Influence of temperature and steam on the products from the flash pyrolysis of Jordan oil shale

Oil shale samples from the Sultani deposit in the south of Jordan, were pyrolysed in a semi‐continuous fluidized bed reactor under nitrogen and nitrogen/steam atmosphere. The pyrolysis temperature between 400 and 650°C were investigated. Increasing the pyrolysis temperature from 400 to 520°C caused a large increase in the oil yield. Further increase of the pyrolysis temperature resulted in a decrease in oil yield and a large increase in the evolved gases. This increase in the hydrocarbon gas yield was attributed to oil thermal cracking reactions. The evolved gases were composed of H₂, CO, CO₂, and hydrocarbons from C₁ to C₄. The presence of steam improved the oil yield which may be a result of reducing the degree of decomposition. The derived oils were fractionated into chemical classes using mini‐column liquid chromatography. Copyright © 2002 John Wiley & Sons, Ltd.     

Catalytic hydrodeoxygenation of dehydrated liquid phase pyrolysis oil

Biomass has been considered as promising energy source that should be able to suffice the increasing energy demand in the future. Therefore, new biomass utilization technologies and concepts are highly desirable. This paper contributes to the understanding of liquid phase pyrolysis oil upgrading that differs from the intensively investigated fast pyrolysis oil. Two new approaches, which were never reported in literature before, where investigated in this paper. At first, the liquid phase pyrolysis oil was dehydrated to lower transportation costs and increase energy density and efficiency of further upgrading steps. At second, a catalyst screening for hydrodeoxygenation (HDO) of dehydrated liquid phase pyrolysis oil was conducted in a batch reactor. Neither the dehydration nor the HDO of dehydrated liquid phase pyrolysis oil were reported in literature by now. The activity of the HDO catalysts Ru/C, Pt/C, and Pd/C as well as a Ni‐based catalyst was compared. HDO was investigated at 250 °C and 100 bar and at 300 °C and 150 bar. HDO of dehydrated liquid phase pyrolysis oil was observed with all catalysts. The Pt/C catalyst was found to be most promising with respect to the oil yield (56 wt.%), the deoxygenation ratio (65%), and hydrogen content (8.6 wt.%). Copyright © 2014 John Wiley & Sons, Ltd.     

Thermal decomposition behavior,characterization and evaluation of pyrolysis products of agricultural wastes

Thermal decomposition behavior during pyrolysis, the composition and the physicochemical characteristics of the pyrolysis products were studied for four agricultural wastes from Southern Greece. These wastes are produced in abundance in the Mediterranean Region but still remain relatively unexploited, while there is also lack or little relevant scientific information. Pyrolysis process for the examined samples was studied using a TGA analyzer and a properly tested and calibrated TG/MS setup, at a heating rate of 10 °C/min up to 850 °C. Determination of important quantitative parameters of pyrolysis as a function of temperature, on an instantaneous or integral basis, and correlation of the evolved gas results with the degradation of pseudocomponents of raw biomass was made possible. The average higher heating value of the pyrolysis light gases was found to be in a satisfactory for energy purposes range of 11.2–14.4 MJ/Nm³. Furthermore, biochars produced at 450, 550 and 650 °C in a fixed bed reactor were found to exhibit calorific value ranging from 20.1 to 28.7 MJ/kg and structural stability. They were also found to have a high nutrients content and below limits or negligible heavy metals content for soils applications, regardless of production temperature.     

Design,simulation and experimental study of a directly-irradiated solar chemical reactor for hydrogen and syngas production from continuous solar-driven wood biomass gasification

The use of concentrated solar energy as the high-temperature heat source for the thermochemical gasification of biomass is a promising prospect for producing CO₂-neutral chemical fuels (syngas). The solar process saves biomass resource because partial combustion of the feedstock is avoided, it increases the energy conversion efficiency because the calorific value of the feedstock is upgraded by the solar power input, and it also reduces the need for downstream gas cleaning and separation because the gas products are not contaminated by combustion by-products. A new concept of solar spouted bed reactor with continuous biomass injection was designed in order to enhance heat transfer in the reactor, to improve the gasification rates and gas yields by providing constant stirring of the particles, and to enable continuous operation. Thermal simulations of the prototype were performed to calculate temperature distributions and validate the reactor design at 1.5 kW scale. The reliable operation of the solar reactor based on this new design was also experimentally demonstrated under real solar irradiation using a parabolic dish concentrator. Wood particles were continuously gasified at temperatures ranging from 1100 °C to 1300 °C using either CO₂ or steam as oxidizing agent. Carbon conversion rates over 94% and gas productions over 70 mmol/g_biomass were achieved. The energy contained in the biomass was upgraded thanks to the solar energy input by a factor of up to 1.21.     

Optimization of the operating conditions for steam reforming of slow pyrolysis oil over an activated biochar-supported Ni–Co catalyst

Highly performing activated biochar-based catalysts were produced for steam reforming of slow pyrolysis oil. The raw biochar obtained from the slow pyrolysis step was physically activated with CO₂ at 700 °C and 1.0 MPa and then employed as support. Preliminary tests on steam reforming of acetic acid at 600 °C showed that using activated biochar-supported catalysts containing 10 wt % Ni and 7 wt % Co led to a conversion above 90% with a relatively slow deactivation rate. When a representative organic model compounds mixture was used as feed, relatively fast deactivation of the catalyst was observed, probably due to the adsorption of heavy organic compounds, which could subsequently react to form not easily desorbable reaction intermediates. However, the dual Ni–Co catalysts exhibited a good performance during the steam reforming of a real slow pyrolysis oil at 750 °C, showing long stability and a constant carbon conversion of 65%.     

Hydrogen production via catalytic pyrolysis of biomass in a two-stage fixed bed reactor system

This study introduces an innovative process of generating hydrogen-rich gas from biomass through the catalytic pyrolysis of biomass in a two-stage fixed bed reactor system. Water hyacinth was used as the biomass feedstock. The effects of various factors such as pyrolysis temperature, catalytic bed temperature, residence time, catalyst, and the nickel content of the catalyst on the pyrolysis productivity were investigated and the yields of H₂, CO, CH₄, and CO₂ were obtained. Results showed that the high productivity of hydrogen can be obtained particularly by increasing the catalytic bed temperature, residence time, and catalysts. The favorable reaction conditions are as follows: a first-stage pyrolysis temperature of 650 °C–700 °C, a second-stage catalytic bed temperature of 800 °C, a catalytic pyrolysis reaction time of 17 min, and a nickel content of 9% (wt %).     

High hydrogen yield and purity from palm empty fruit bunch and pine pyrolysis oils

The benefits of CO₂ sorption enhanced steam reforming using calcined dolomite were demonstrated for the production of hydrogen from highly oxygenated pyrolysis oils of the agricultural waste palm empty fruit bunches (PEFB) and pine wood. At 1 atm in a down-flow packed bed reactor at 600 °C, the best molar steam to carbon ratios were between 2 and 3 using a Ni catalyst. After incorporating steam-activated calcined dolomite as the CO₂ sorbent in the reactor bed, the H₂ yield from the moisture free PEFB oil increased from 9.5 to 10.4 wt.% while that of the pine oil increased from 9.9 to 13.9 wt.%. The hydrogen purity also rose from 68 to 96% and from 54 to 87% for the PEFB and pine oils respectively, demonstrating very substantial sorption enhancement effects.     

Flash pyrolysis of jatropha oil cake in electrically heated fluidized bed reactor

Fluidized bed flash pyrolysis experiments have been conducted on a sample of jatropha oil cake to determine particularly the effects of particle size, pyrolysis temperature and nitrogen gas flow rate on the pyrolysis yields. The particle size, nitrogen gas flow rate and temperature of jatropha oil cake were varied from 0.3 to 1.18 mm, 1.25 to 2.4 m³/h and 350 to 550 °C. The maximum oil yield of 64.25 wt% was obtained at a nitrogen gas flow rate of 1.75 m³/h, particle size of 0.7–1.0 mm and pyrolysis temperature of 500 °C. The calorific value of pyrolysis oil was found to be 19.66 MJ/kg. The pyrolysis gas can be used as a gaseous fuel.     

Hydrogen enriched syngas production via gasification of biofuels pellets/powders blended from olive mill solid wastes and pine sawdust under different water steam/nitrogen atmospheres

In this work, we study the gasification of pellets produced, after densification, by blending olive mill solid wastes, impregnated or not by olive mill waste water, and pine sawdust under different steam/nitrogen atmospheres. The charcoals necessary for the gasification tests were prepared by pyrolysis using a fixed bed reactor. The gasification technique using steam was chosen in order to produce a hydrogen-enriched syngas. Gasification tests were performed using macro-thermogravimetric equipment. Tests were carried out at different temperatures (750 °C, 800 °C, 820 °C, 850 °C and 900 °C), and at different atmospheres composed by nitrogen and steam at different percentages (10%, 20% and 30%). Results show that the mass variation profiles is similar to the usual lingo-cellulosic gasification process. Moreover, the increase of temperatures or water steam partial pressures affects positively the rate of conversion and the char reactivity by accelerating the gasification process. The increase of the gasification yields demonstrates the promise of using olive mill by-products as alternative biofuels (H₂ enriched syngas).     

Non-isothermal pyrolysis of the mixtures of waste automobile lubricating oil and polystyrene in a stirred batch reactor

Kinetic tests on pyrolysis of the mixture of waste automobile lubricating oil (WALO) and polystyrene (PS) were carried out with a thermogravimetric analysis (TGA) technique at a heating rate of 0.5 °C/min, 1.0 °C/min and 2.0 °C/min in a stirred batch reactor. WALO and PS were mainly decomposed 400–455 °C and 370–410 °C, respectively. The mixture of WALO and PS, however, was decomposed between 355 °C and 470 °C, and decomposition proceeded in two broad steps. The apparent activation energies for the pyrolysis of WALO/PS mixture were in the range of 176 kJ mol⁻¹–369 kJ mol⁻¹ at various conversions of 1–100%. The effect of heating rate on the product distribution was studied. The carbon number distribution of the produced oil shifted slightly to light hydrocarbons with a decrease in heating rate. The selectivity of hydrocarbons corresponding to the styrene monomer was high for the pyrolysis of the WALO/PS mixture.