Pirolisis Steam Boiler
Pyrolysis Steam Boiler from industrial waste for bio-oil production
Potato peels, industrial food waste, are hydrolyzed under three different atmospheres: static, nitrogen, and steam, to produce bio-oil and its derivatives. The oil yield obtained at 550 °C is 24.77% in a static atmosphere, while it reaches 27.11% in a nitrogen atmosphere. Furthermore, the use of steam leads to a sharp increase in oil yield by 41.09% with a steam velocity of 1.3 cm/s. TG-DTA analysis is applied to the raw material to investigate thermal degradation. The liquid product obtained under the most suitable conditions is characterized by elemental analysis, FT-IR, and 1H NMR. Column chromatography is used to separate bio-oil into its derivatives. The asphaltene fraction of bio-oil decreases under a steam atmosphere. Gas chromatography is also used to investigate the C distribution. Characterization has shown that bio-oil obtained under a steam atmosphere is more favorable than that obtained in static and inert atmospheres. Furthermore, a comparison of the H/C ratio of pyrolysis oil with conventional fuels indicates that the H/C ratio of the oil obtained in this study falls between light and heavy crude oil products. It can be concluded that potato peels can be considered a promising biomass candidate for vegetable oil production.
boiler fuel oil gas
During the hydrodeoxygenation of triglycerides into motor fuels, isomerization reactions play a crucial role because the cold flow properties of the products are significantly improved by increasing the isoparaffin content in the boiling range of gas oil. Therefore, the goal of our research program is to select and investigate suitable catalysts for producing products containing relatively high isoparaffin content over an extended period in a preserved activity. Both non-presulfided CoMo/Al2O3 and NiMo/Al2O3 catalysts have isomerization activity; however, in the case of CoMo/Al2O3, the catalyst conversion of triglycerides is high, ranging from 25.1 to 30.5 abs%, and the yield is 24.2-24.6 abs%, with a higher i-paraffin/n-paraffin ratio of 0.18-0.33, as compared to NiMo/Al2O3 under favorable conditions. Thus, products with more favorable cold flow properties can be produced on the CoMo/Al2O3 catalyst.
The objective of this work is to study the Fischer-Tropsch (FT) synthesis of model biosyngas (33% H2, 17% CO, and 50% N2) in a single-tube fixed-bed FT reactor. The FT reactor consists of a shell and tube with high-pressure boiling water circulating throughout the shell. Non-spherical cobalt catalyst pellets are used under the following reaction conditions: wall temperature 473 K, pressure 20 bar, and gas hourly space velocity (GHSV) of 37 to 180 NmL.gcat-1.h-1. The performance of the FT reactor is also validated by developing a pseudo-homogeneous 2D model incorporating transport equations and reaction rate equations. Good agreement between model predictions and experimental results is obtained. This developed model is expanded to predict and quantify the influence of FT kinetics and determine the effects of tube diameter and wall temperature. Predicted behavior for CO and H2 conversion, hydrocarbon productivity (especially CH4 and C5+), and fluid temperature along the reactor axis are analyzed.
Pressurized gas produced from biomass is a renewable resource that has gained much attention for various industrial applications, such as hydrogen production, chemicals, or high-grade fuels. Therefore, the University of Technology Vienna, in collaboration with BioEnergy 2020+, operates a bubbling fluidized bed gasification plant. The pressurized research unit (PRU) is capable of gasifying wood chips, wood pellets, coal, and other solid fuels with gasifying agents, including air, steam, oxygen, or carbon dioxide. This paper provides results on parameter variations in this plant concerning the producer gas composition. The feedstock is wood pellets, and olivine is used as the bed material with an average particle size of 0.5 mm. The varying parameters are temperature (720-900 °C), pressure (1-5 bar), air ratio (0.2-0.4), gasifying agents (air, steam, oxygen), biomass feed rate (4.5–8 kg/h), and fluidization conditions of the fluidized bed reactor (fluidization number (3–7)).
deaerators steam boiler
The objective of this work is to develop a simple procedure, which avoids the need for a binder, to obtain active monolithic carbon from waste precursor (pitch tar from coal) suitable for CO2 capture and/or separation. The main task of this process consists of the nitration process of coal pitch tar. The nitration step on coal pitch tar is characterized by different techniques, such as infrared spectroscopy and thermogravimetric analysis. The nitration treatment results in the oxidation of pitch tar molecules, leading to hydrogen consumption and producing an oxygenated and nitrogenated surface complex. As a consequence of this oxidation, nitration-coal tar pitch is an infusible material, allowing monolithic carbon pieces to avoid fusion. The decomposition of this surface complex during monolithic carbonization results in narrow microporosity, suitable for CO2 capture from the gas stream at room temperature. The molecular sieving properties of these materials are studied by CH4 and CO2 adsorption kinetics.
In this study, sulfuric acid (H2SO4) was used in the pretreatment of palm oil sludge for biodiesel production through esterification, followed by a base-catalyzed transesterification process. The purpose of the pretreatment process is to reduce the free fatty acid (FFA) content from the high FFA content (> 23%) of palm oil sludge (SPO) to a minimum level for biodiesel production (> 2%). Acid-catalyzed esterification was performed to evaluate the low FFA content in processed SPO with the effects of other parameters, such as the molar ratio of methanol to SPO (6:1–14:1), temperature (40–80 °C), reaction time (30–120 minutes), and stirring speed (200–800 rpm). The research results showed that the FFA content in SPO reduced from 23.2% to less than 2% FFA using 0.75% w/w sulfuric acid with a molar ratio of methanol to oil 8:1 during a 60-minute reaction time at 60 °C. Transesterification results with esterified SPO showed that the biodiesel yield was 83.72% under the process conditions of a molar ratio of methanol to SPO of 10:1, a reaction temperature of 60 °C, a reaction time of 60 minutes, stirring speed of 400 rpm, and 1% (w/w) KOH. The biodiesel produced from SPO complies with EN 14214 and ASTM D 6751 standards.
Malaysia rejects refuse-derived fuel (RDF) because a small part of pyrolysis waste recycling in a batch rig continues to be stirred at 450 °C with and without a catalyst. Various types of catalysts were used to enhance the quantity and quality of pyrolysis products: Y-zeolite, equilibrium FCC, ZSM-5, Ni-Mo catalyst, Co-Mo catalyst, silica-alumina, and alumina. Gas chromatography, Fourier-transformed infrared spectroscopy, X-ray spectroscopy, and other standard methods were used for product identification. RDF pyrolysis yielded gas with a yield of 15.7-27.8%, pyrolytic oil 9.8-17.8%, and water (9.2-12.8%) depending on the applied catalyst type. Data show that the volatile fraction (both gas and pyrolytic oil) slightly increased with the catalyst, especially for Y-zeolite and ZSM-5. The gas consists of CO, CO2, hydrogen, and hydrocarbons. Major chemical compounds such as aromatic, branched, and non-branched in the pyrolytic oil were influenced by the catalyst, e.g., main carbon framework isomerization and aromatization, showing higher yields mainly when Y-zeolite and ZSM-5 were applied. The contents of phenol, 1,3-diol benzene, and methylphenol in the pyrolytic oil obtained from non-catalytic pyrolysis decreased by 45.0%, 40.9%, and 38.0%, in the presence of zeolite Y, and by 39.4%, 36.9%, and 26.9% more with Co-Mo catalyst compared to non-catalytic pyrolysis, respectively. Sulfur, nitrogen, and chlorine were found as contaminants in the pyrolytic oil, but their contaminant concentrations can be significantly reduced with catalyst use. Catalyst activity in impurity reduction followed the order Ni-Mo-cat. > Co-Mo-cat. > Y-zeolite > FCC > ZSM-5 > Al2O3/SiO2 > Al2O3. According to EDXRFS analysis, the char consisted of impurity elements such as Ca, Ti, Fe, Cu, Zn, and Pb.
css Copy codeThis work reports the development of a method for the determination of lead in aviation gasoline samples using electrothermal atomic absorption spectrometry (ETAAS). The samples were emulsified before injection into the spectrometer to avoid the high instability observed in the signal when samples were injected directly without any treatment. Stable detergent emulsions were obtained by mixing 1 mL of 7% m/v Triton X-100 solution containing 10% v/v HNO3 with 4 mL of aviation gasoline. These emulsions provided constant integrated absorbance signals for at least 5 hours. Several parameters related to emulsion formation (Triton X-100 and HNO3 concentration) and temperature program (pyrolysis and atomization temperature, heating rate, and final drying step temperature) were evaluated. The concentration of Triton X-100 and HNO3 in the solution used to form the emulsion affected lead measurement sensitivity as well as the heating rate used in the drying step. The use of a chemical modifier was required, as the conventional Pd modifier provided better performance than the permanent Ir modifier. The detection and quantification limits derived for the methodology were 1.2 and 4.0 µg L-1. Six aviation gasoline samples were analyzed, and lead concentrations varied between 11.6 and 64.2 µg L-1. Recovery tests were performed to prove the accuracy of the procedure, and recovery percentages between 88 and 112% were observed.
Combustion of fuel under oxygen-enriched atmospheres has been well investigated over the past few decades in various types of combustion, ranging from diesel engines to coal-fired boilers. Most research has found a significant reduction in NOx emissions during Oxy-coal combustion. In this paper, NOx combustion chemistry under O2/CO2 and air atmospheres is studied using a detailed kinetic model. The suitable reaction mechanism was selected based on a comparison between calculated results and experimental data. The influence of various parameters (temperature, CO2 concentration) on NOx conversion is investigated. The chemical effects of high CO2 concentration on NO formation and destruction processes are studied. Based on the investigation through fundamental chemical reactions, it can be concluded that high CO2 concentration plays a pronounced role in the NOx conversion process. In addition, dominant reaction steps contribute to both NO production and destruction, and the most important reactions for NO reduction under different atmospheres have been discussed.
Layered double hydroxides (LDHs) are a class of synthetic two-dimensional nanostructured anionic clays whose structure can be described as sequentially nano-ordered materials. This research aims to use nano-layered materials as hosts for organic guests with required functional groups, such as azo compounds, to modify the surface properties of LDH from hydrophilic to hydrophobic and enhance the adsorption capacity for sulfur and aromatic compounds through the creation of nano-hybrid materials. Large anionic pigments (sodium phenyl azobenzoate) were intercalated into Zn-Al LDH, and a complex host-guest supramolecular interaction system was formed.
We have examined the unusual bi-functionality effect caused by hybridization to remove sulfur and aromatics from slack wax. The results clearly show that nano-layered materials reduce the sulfur and mono-aromatic compound content in slack wax. In doing so, it entirely eliminates di-aromatic compounds. In the same trend, nano-hybrid materials exhibit high efficiency in removing aromatic and sulfur compounds from crude oil. This leads to improved physical properties of slack wax and raw petrolatum.
This work investigates the production of ethyl ester fatty acids (biodiesel) from the transesterification of soybean oil in supercritical ethanol in a continuous free-catalyst process using carbon dioxide as a co-solvent. Experiments were carried out in a microtube reactor in the temperature range of 523 K to 598 K, from 10 MPa to 20 MPa, molar ratio of oil to ethanol from 1:20 to 1:40, and co-solvent-to-substrate mass ratio of 0.05:1 to 0.2:1. The results show that the yield of ethyl ester obtained increases with the addition of carbon dioxide to the system. A significant yield was achieved at 598 K, 20 MPa, molar ratio of oil to ethanol 1:20, and using CO2 for a co-solvent-to-substrate mass ratio of 0.2:1. Gas-to-liquid (GTL) and coal-to-liquid (CTL) Fischer-Tropsch processes using high-temperature gasification (entrained flow) all face the same purification challenge, meeting the EN590 density specification of 820 kg/m^3 at 15°C for the produced distillate. However, Fischer-Tropsch distillate can be mixed with high-density distillate from sources such as crude oil, direct coal liquefaction, or coal pyrolysis products in an effort to adjust to diesel density requirements. Dry bed dry bottom (FBDB) gasification technology can be combined with high-temperature Fischer-Tropsch synthesis (HTFT) to provide a way to produce CTL transportation fuels with final specifications. FBDB gasification tar results in a hydroprocessor process that yields high-density distillate, while HTFT distillate that is hydrotreated becomes a highly paraffinic product with high octane but low density.Coal combustion is a series of complex reactions dominated by transport mechanisms. An aspect that is less understood is the influence of excluded pyrite mineral fragmentation on the combustion heat history and sulfur release. To explore this effect, fragmentation is incorporated into a mathematical model consisting of several stages, namely: particle heating, decomposition into pyrrhotite, fragmentation, and oxidation. Computational fluid dynamics (CFD) dynamic models are used to verify heat and mass transfer predictions from the model. The model is then solved to simulate the heat and mass balance of pyrite particle combustion in a combustion environment.
Fragmentation was found to increase particle temperature and sulfur release rates compared to the case without fragmentation, speeding up the increase in particle temperature towards its melting point. Increased oxygen content in the bulk environment reduced the time required for particles to reach their melting point and for complete sulfur release due to increased oxidation reaction rates. Model results also show that small pyrite particles require less time to decompose and reach the melting temperature, indicating that smaller particles spend more time in the liquid state and react more completely.
Pentane-insoluble asphaltenes are processed by thermal cracking and catalytic hydrocracking over NiMo/γ-Al2O3 in a microbatch reactor at 430°C. Kinetic analysis indicates that first-order kinetics fit the conversion data for reaction times up to approximately 30 minutes but deviate significantly from the data for times longer than 30 minutes, while second-order kinetics fit the reaction time data up to 60 minutes adequately, yielding rate constants of 1.704 × 10^-2 and 9.360 × 10^-2 wt frac^-1 min^-1 for two cracking processes. Furthermore, a three-lump kinetic model is proposed to incorporate parallel reactions of asphaltenes to produce liquid (k1) and gas + coke (k3), and sequential reactions from liquid to gas + coke (k2). The evaluated values of k1 are 1.697 × 10^-2 and 9.355 × 10^-2 wt frac^-1 min^-1, k2 is 3.605 × 10^-2 and 6.347 × 10^-3 min^-1, and k3 is 6.934 × 10^-5 and 4.803 × 10^-5 wt frac^-1 min^-1 for thermal cracking and catalytic hydrocracking of asphaltenes, respectively. Selectivity analysis shows that the catalytic hydrocracking process promotes liquid production and effectively inhibits coke formation.This paper describes the characterization of Pakistan lignite coal, humic acid derivatives (HAL) and nitrohumic acid (NHA), along with standard leonardite humic acid (LHA). The research employs chromatographic and spectroscopic techniques to characterize the coal structure and derivatives. Pyrolysis combined with GC/MS is performed with and without a methylating agent (tetramethylammonium hydroxide). Pyrolysis studies resulted in the release of mainly methyl ester fatty acids, various hydrocarbons, and α,ω-dicarboxylic acid methyl esters. Triterpenoid compounds, syringic and ρ-coumaric, and aromatic compounds derived from lignin groups are also detected. Fourier-transform infrared (FT-IR) and NMR data helped evaluate the influence of coal rank on regeneration and nitration processes concerning the chemical structure composition of coal and derivatives. FT-IR spectra of the four materials are similar except for NHA, which shows an absorption band at 1532 cm^-1, confirming the presence of -NO2 groups. ^13C NMR reveals higher aromaticity and fewer hydroxylalkyl substances in HAL compared to NHA. Elemental composition and functional group content of the four materials are also reported.
Combining results from different analysis techniques provides a better understanding of Pakistan coal properties and helps in its future utilization.
Experimental investigations were conducted to study the influence of dual-fuel combustion characteristics on exhaust gas emissions and combustion performance in a diesel engine using biogas-biodiesel dual-fuel. In this work, combustion pressure and heat release rate were evaluated under various conditions to analyze the combustion characteristics and emissions for single fuels (diesel and biodiesel) and dual-fuel combustion (biogas-diesel and biogas-biodiesel) modes in a diesel engine. Additionally, to compare engine performance and exhaust gas characteristics with combustion modes, fuel consumption, exhaust gas temperature, efficiency, and exhaust gas emissions were also investigated under various test conditions. For the dual-fuel system, the intake system of the test engine was modified to be converted into biogas and biodiesel dual-fuel injection during the intake process by two electronically controlled gas injectors installed in the intake pipe.
The results of this research show that the combustion characteristics of single fuels for biodiesel and diesel exhibit the same pattern at various engine loads. In dual-fuel mode, the peak pressure and heat release for biogas-biodiesel are slightly lower than for biogas-diesel at low loads. At 60% load, biogas-biodiesel combustion shows slightly higher peak pressure, rate of heat release (ROHR), and indicates indicated mean effective pressure (IMEP) compared to diesel. Additionally, ignition delay for biogas-biodiesel shows a shorter trend compared to ULSD dual injection due to the higher cetane number (CN) of biodiesel. Significantly lower NOx emissions are emitted under dual-fuel operation for both sample fuels compared to single-fuel mode under all engine load conditions. Also, biogas-biodiesel provides superior performance in reducing soot emissions due to the absence of aromatics, low sulfur, and oxygen content for biodiesel.
Biodiesel production is rapidly expanding worldwide, making it more important to produce this fuel with greater energy efficiency. In this paper, we observe a series of transesterification reactions of soybean oil and methyl alcohol catalyzed by potassium hydroxide. Observations are made using non-invasive optical techniques. This technique is useful in indicating the endpoint of the transesterification reaction or determining when the reaction reaches a state of chemical equilibrium. This study enables improved follow-up of the transesterification reaction by optimizing the reaction time with better monitoring systems.
Thermodynamic Analysis of FAME and FAEE Production Kinetics Using Novozyme 435 as a Catalyst
Biodiesel is an alternative biofuel expected to replace diesel. One of the most promising technologies for biodiesel production is enzymatic catalysis. However, the low catalytic performance of most enzymes used makes such a process expensive and time-consuming. This work describes a kinetic study of enzymatic biodiesel production at different temperatures using methanolysis or ethanolysis, using immobilized lipase from Candida antarctica (Novozym 435) as the catalyst. The kinetic reactions are monitored by GC, and the data is used to perform thermodynamic analysis of the transition state using the Arrhenius equation. We found that methanolysis is faster than ethanolysis at temperatures above 13°C. Thermodynamic analysis of the reaction kinetics shows that methanol is preferred as the acyl acceptor due to the positive change in activation entropy of the reaction. This data may be useful in the development of new enzymes and processes for enzymatic biodiesel production.
NiMoS-alumina-silica composite catalysts were examined in single and double-layer catalyst bed configurations in a high-pressure (5 MPa) flow reactor to achieve ultra-low sulfur diesel fuel (10 ppm). Three types of alumina-silica composite supports were prepared by co-precipitation to control particle size and alumina and silica composition. The SiO2 content was found to affect the catalytic performance, with the best being around 27% regardless of the preparation conditions. The crystal size of alumina controls the acidity and surface area of the support, key factors influencing catalytic performance. NiMoASA-2 (27), prepared by procedure 2, achieved 4.5 and 3 ppm S at 345 and 360°C, respectively, in a single-bed reactor at a liquid hourly space velocity (LHSV) of 1 h^-1. NiMoASA-2 (27) achieved the best performance of the supports examined in this study. Two-layer catalyst beds containing commercial CoMoS (LX6) and NiMoASA-2 (27) on the first and second beds at temperatures of 345 and 360°C achieved 5 and 2 ppm S, indicating better performance at higher temperatures. The reaction sequence for the hydrodesulfurization (HDS) of refractory sulfur species is almost the same as that for NiMoASA-2 (27), which is significantly higher than that for the commercial CoMoS catalyst. NiMoS-alumina-silica supported in the second bed of the two-layer catalyst bed achieved less than 10 ppm S for refractory sulfur species with about 500 ppm S.
Footwear leather waste (FLW) has shown some different features from conventional biomass, including high sulfur and chromium concentrations. This paper presents the experimental results obtained from the gasification and combustion of FLW carried out in a semi-pilot plant (350 kWth). Corrosion testing was performed with low-carbon steel and three stainless steels at around 500°C. The corrosion rates obtained for all tested alloys were significantly lower than those observed for other types of biomass. The presence of chromium oxide and sulfur dioxide in the flue gas was associated with the reduction of the corrosion rate.
This research focuses on the characterization of heavy and medium crude oils in a limestone matrix using differential scanning calorimetry (DSC) and thermogravimetry (TG-DTG). The resulting DSC and TG-DTG curves for two different crude oil + limestone mixtures show that crude oil undergoes two major transitions when subjected to a continuously oxidizing environment, known as low-temperature and high-temperature oxidation rates. Kinetic analysis in the low-temperature and high-temperature oxidation regions was performed using two different kinetic methods. Throughout the study, it was observed that the activation energy values for the samples varied between 2.40-10.62 and 42.3-181.9 kJ/mol in the low-temperature and high-temperature oxidation regions, respectively.
Microencapsulation carrier, CME, is a technique to form a thin layer of metal oxide or hydroxide on the surface of pyrite using an organic carrier that is water-soluble combined with metal ions. This research investigates the effect of CME using the tris-catecholato complex of Si^4+, Si(cat)3^2- on pyrite-coal separation using dynamic bubble pick-up experiments and Hallimond tube flotation experiments with coal, pyrite, and coal-pyrite mixtures. Mineral samples were treated in 0-5 mol m^-3 Si(cat)3^2- solution at pH 4-9 at treatment times of 1-24 h. Dynamic bubble pick-up experiments show that CME treatment changes the surface of pyrite from hydrophobic to hydrophilic but does not affect the coal hydrophobic surface. Hallimond tube flotation experiments of coal-pyrite mixtures at pH 7-9 with kerosene as the collector show that pyrite floatability is selectively depressed after 1 h of CME treatment with 0.5 mol^-3 Si(cat)3^2-, while coal and pyrite float without treatment. This indicates that CME treatment is effective in suppressing pyrite floatability in coal-pyrite flotation.
The behavior of pollutant gas emissions during the combustion of a mixture of wheat straw and coal was experimentally examined using thermogravimetric analysis (TGA). Typical anthracite coal and central Chinese wheat straw were chosen for this study. The coal-to-wheat straw ratio based on mass was set at 10:90, 15:85, 40:60, and 60:40, and the firing was carried out using simulated air with oxygen and nitrogen gases. The characteristics of gas pollutant emissions such as HCl, SO2, CO2, and NOx were determined by Fourier transform infrared (FTIR) measurements. The results show that HCl, SO2, CO2, and NOx emissions are closely related to the stages of combustion of easily volatile matter and char. HCl emissions are primarily released during the volatile combustion at temperatures between 220 and 450°C. The HCl emission profile against temperature shows a single peak, and the HCl peak occurs at 310°C for all mixtures regardless of their ratio. The emission profiles of SO2 and NOx against temperature have characteristics of two peaks. The first peak occurs around 320°C for all mixtures, and the second peak shifts to higher temperatures as the coal content increases in the mixture. The study indicates that combining straw and coal can achieve better emission control by reducing the magnitude of peak releases. Analytical results show that a sample mixed with 40% coal and 60% straw produced the lowest levels of HCl, NOx, and SO2 gas emissions. CO2 emissions are mainly produced during the char combustion stage and increase linearly with carbon content in the mixture.
The chemical interactions responsible for sintering in coal mineral mixtures were investigated in air and N2. Mineral mixtures were created by blending kaolin, pyrite, quartz, calcite, hydromagnesite, FeCO3, and anatase in a fixed ratio. The mineral mixture was pelletized and heated to 1100 °C to evaluate sintering by recording compressive strength values and visual assessment using scanning electron microscopy (SEM). The chemical interactions responsible for trends in compressive strength were investigated with simultaneous thermal gravimetry and differential analysis (TG/DTA), as well as X-ray diffraction. The results showed that the formation of anhydrite (CaSO4) was responsible for increasing the mechanical strength in mineral mixture pellets heated in air at temperatures higher than 400 °C. CaSO4 is formed from the decomposition reaction of pyrite and calcite (SOx and CaO). TG/DTA results also indicated that the reaction with pyrite in air led to the decomposition of calcite in the mixture at lower temperatures than observed for calcite alone. Pellets heated in N2 did not show an increase in mechanical strength during heat treatment due to the lack of CaSO4 formation in the inert atmosphere. However, SEM analysis revealed that sintering did occur at higher temperatures in N2. A decrease in compressive strength values was observed in air at temperatures from 900 °C to 1100 °C. The reasons for the decrease in compressive strength included increased porosity, decomposition of CaSO4, and changes in the characteristics of aluminosilicate phases.
Diphenyl carbonate (DPC) is synthesized from CO2 and phenol catalyzed by Lewis acids. Compressed CO2 is used as both a reactant and solvent. It was found that phenol conversion and DPC yield depended on the Lewis acid center, with zinc halides exhibiting better catalytic performance than aluminum halides. The reaction of CO2 with phenol was sensitive to pressure, temperature, and reaction time and was enhanced using triethylamine as an acid acceptor. A DPC yield of 31.7% was obtained under optimized reaction conditions: 9 MPa at 100 °C for 3 hours.
The effect of low-temperature oxidation (LTO) on Fosterton oil sand asphaltenes (FOSA) is examined in this study. Fosterton oil sand asphaltenes were subjected to air oxidation at a low temperature, approximately 220 °C, for a certain period (6.33 hours) in a fixed-bed tubular reactor. The exhaust gas was analyzed for CO, CO2 , and oxygen content. The m-ratio (m=CHAICHAI2) of the fuel was obtained from effluent gas analysis. Residue of the LTO was then analyzed to determine its elemental composition. The low H/C ratio (0.8) found in the LTO residue indicated that it contained condensed polynuclear aromatic rings. The thermal behavior and combustion kinetics of the residue were investigated using thermogravimetry (TGA) analysis. Non-linear regression methods were used to analyze the combustion reaction kinetics. The results showed that the activation energy for asphaltene combustion was 66.73 kJ/mol, and the pre-exponential factor was 1.2 x 104 min-1.
The possibility of extracting hydrocarbons from Huadian oil shale with sub-critical water was found in a stainless steel vessel. The effects of temperature and pressure on hydrocarbon extraction were studied. After the extraction experiments, solid, liquid, and gas phase samples were collected and characterized. The extracted yield could reach 7% by weight (wet basis) when oil shale was extracted at 260 °C for 2.5 hours at a pressure of 15 MPa. Thermogravimetry (TG) results showed that the weight loss of the solid residue was much smaller than that of the original oil shale. This indicates that kerogen components had partially decomposed due to sub-critical water treatment. Gas chromatography-mass spectrometry (GC-MS) analysis revealed over 300 identifiable peaks in the extraction solution after processing at 330 °C and 18 MPa. A significant amount of high-molecular-weight hydrocarbons gradually decomposed into smaller molecular-weight hydrocarbons and polycyclic and heterocyclic compounds with increasing pressure and temperature. This suggests that sub-critical water is capable of breaking down kerogen into smaller hydrocarbon compounds at relatively low temperatures.
This is the first preliminary investigation into the heterogeneous property distribution of mineral matter in one of the important Assam (India) coal powders using computer-controlled scanning electron microscopy (CCSEM). The research results show that clay minerals, quartz, pyrite, and pyrrhotite make up the majority of the mineral matter. Small minerals, such as calcite, dolomite, ankerite, barite, oxidized pyrrhotite, and gypsum, were also observed in the samples. The particle size distribution (PSD) of the included minerals was generally observed to be finer than the excluded minerals in coal. Consequently, mineral-rich coals include more fine mineral particles, which can affect their reactivity. Regarding the association of individual mineral species, the proportion included to excluded was found to be higher in the case of larger particles. Regarding the mode of occurrence of major inorganic elements, Si was mostly found as quartz and clay minerals, while Al was primarily present in silicate minerals. Fe was mainly present as iron sulfides, iron oxides, and Fe-Al silicates. Sulfur was divided into iron sulfides and gypsum. Most of the Ca occurred as carbonate and gypsum, with a small portion associated with clay minerals. Mg was mainly present as dolomite and clay minerals, with a small portion present as ankerite. The majority of alkali elements were associated with aluminosilicates. P was mainly associated with kaolinite and/or present as more complex compounds containing Al, Si, and other elements since no apatite was found in the studied coal. Ti was primarily present as rutile and kaolinite.
The effect of the type and amount of hardeners, such as ammonium nitrate, ammonium carbonate, and nitric acid, on the molasses-bound briquettes made from fines of anthracite or breeze coke was investigated. Among the hardeners studied, the best results were obtained with 2.5% ammonium nitrate hardener. Briquettes produced with this hardener were highly resistant to water but not waterproof, and their tensile strength was inadequate for use as metallurgical coke substitutes. Therefore, briquettes were prepared with molasses containing 2.5% ammonium nitrate hardener and air-dried binder tar pitch. When the mixed binder was used for the production of anthracite or breeze coke briquettes, they became waterproof after drying at 200 °C for 2 hours, and their tensile strength was found to be sufficient for use as a substitute for coke oven coke. The briquettes, after preservation, can be directly charged into the blast furnace without high-temperature carbonization. As molasses and tar pitch are relatively inexpensive and readily available materials in coal, the investigated process could be an economical way to produce high-quality coke.
Biodiesel has attracted significant attention as a renewable, biodegradable, non-toxic fuel and can contribute to addressing energy problems, significantly reducing greenhouse gas emissions.
The first stage of this work is to simulate various alternative processes for biodiesel production. The method used for biodiesel production is transesterification of vegetable oil with alcohol in the presence of a catalyst. The raw materials used are palm oil and waste cooking oil.
The second stage is a life cycle analysis of all the alternatives studied, followed by an economic analysis of alternatives that have a small impact and are more promising from an economic perspective. Finally, we proceed to compare various alternatives from both a life cycle and economic analysis perspective.
The feasibility of all processes was demonstrated, and the obtained biodiesel has good specifications.
From a life cycle analysis perspective, the best alternative is the alkali catalysis process with acid pre-treatment for waste cooking oil.
Economic analysis was carried out for the aforementioned processes and for processes using crude oil, methanol, and sodium hydroxide. These processes have lower investment costs, but the alkali catalysis process with acid pre-treatment, which uses waste oil as the main raw material, is much more profitable and has a smaller environmental impact.
The utilization of biomass ash as a soil improvement material is limited by the allowed heavy metal input. It is known that heavy metal concentrations increase in the fine ash fraction. In this study, two models were investigated to describe the distribution of various heavy metals in different size fractions of fly ash from a biomass combustion plant that burned wood chips. The second model assumes a concentration dependency of heavy metals from particle diameter to the correlated variable N strength. This model was then used in the calculations to determine the particle size cut-offs needed for the classifier to produce coarse fractions with heavy metal concentrations below the Austrian limit for soil improvement materials.
The pyrolysis and combustion behavior of original lignite, olive residue, and a 50/50 wt.% mixture under air and oxy-fuel conditions were investigated using a thermogravimetric analyzer (TGA) combined with Fourier-transform infrared spectrometry (FTIR). Pyrolysis tests were conducted in nitrogen and carbon dioxide environments, which are major dilution gases of air and oxy-fuel environments. The results of pyrolysis for the parent fuel and the mixture showed nearly the same weight loss profile up to 700 °C in both of these environments, indicating that CO2 behaves as an inert gas in this temperature range. However, further weight loss occurred in the CO2 atmosphere at higher temperatures due to CO2 gasification reactions that led to a significant increase in the formation of CO and COS, as observed in the FTIR evolution profiles. Comparing the experimental pyrolysis profiles with the theoretical profiles of the mixture samples revealed no synergy in both atmospheres. Combustion experiments were performed in four different atmospheres: air, oxygen-enriched air (30% O2-70% N2), oxy-fuel environment (21% O2-79% CO2), and oxygen-enriched oxy-fuel environment (30% O2-70% CO2). Substituting N2 in the combustion environment with CO2 led to a slight delay (maximum weight loss rate and higher burnout temperature) in the combustion of all samples. However, this effect was found to be more significant for olive residue than for lignite. Increased oxygen levels shifted the combustion profile to lower temperatures and increased the weight loss rate. The combustion profile of the mixed olive residue/lignite was intermediate between the two fuels. Comparing experimental and theoretical combustion profiles and the characteristic temperatures of the mixed samples indicated synergistic interactions between the parent fuels during co-combustion of olive residue and lignite.
Processing reactions with waste plastic, petroleum residue, and coal were carried out to determine the individual and mixed behavior of these materials using lower pressure and cheaper catalysts. The plastic used in this research is polypropylene. The thermodegradative behavior of polypropylene (PP) and PP/residue/petroleum coal mixtures was investigated in the presence of solid hydrocracking (HC) catalyst. Comparisons between various catalysts were made based on the observed temperature. With the addition of petroleum residue and coal, the higher temperature for the initial weight loss of PP shifted to lower values. The catalysts were also tested in a fixed-bed micro-reactor for the pyrolysis of polypropylene, petroleum residue, and coal, separately and mixed together in nitrogen and hydrogen atmospheres. ° C and gas were obtained together with some heavy oil and insoluble materials such as gums and coke. The results obtained from the recycling of polypropylene with coal and petroleum residue are very encouraging because this method seems feasible enough to convert plastic into liquid coal products and to increase petroleum residue and plastic waste.
Sulfate-promoted hafnia containing various hafnia compositions (1-10% by weight) was prepared by deposition method in an attempt to finally bring n-butane isomerization reaction. The catalyst samples were calcined under a dry air flow at 600 ° C. Structural and crystal changes were monitored by FTIR and XRD, while texture changes were estimated by low-temperature N 2 adsorption. FTIR spectroscopy was used to characterize hydroxyl groups and to determine the concentration of Brönsted and Lewis acid sites of pyridine adsorption. Catalytic activity, stability, and selectivity of catalyst samples were tested for n-butane isomerization at 250 ° C. The results show that the presence of a small hafnia content increases the surface density of sulfate, stabilizes the tetragonal zirconia phase, increases the number and strength of Brönsted acid sites, and increases the initial catalytic activity of the samples. Increasing the hafnia content to 5 and 10% by weight is accompanied by the formation of a monoclinic hafnia phase, which results in a drastic decrease in the number of Brönsted acid sites and the initial activity of the catalyst. N-butane isomerization occurs through a bimolecular path with the formation of iso-butane, propane, and pentane as the main products. Regardless of the high activity of the samples, the catalyst quickly becomes inactive during the first hour of the reaction due to the formation of coke. Catalyst deactivation at 450 ° C with dry air flow before catalytic reaction suggests that coke formation is the main source of catalyst deactivation.
Production of alternative fuels was carried out by pyrolysis of waste vehicle tires under nitrogen (N 2 ) and with calcium hydroxide (Ca(OH) 2 ) as a catalyst. The sulfur content of the obtained liquid was reduced by using Ca(OH) 2 . The liquid fuel from waste vehicle tires (TF) was then used in a diesel engine to blend with diesel fuel at 5% (TF5), 10% (TF10), 15% (TF15), 25% (TF25), 35% (TF35), 50% (TF50), and 75% (TF75) wt. and pure (TF100). Performance characteristics such as engine power, engine torque, specific brake fuel consumption (bsfc), exhaust gas temperature, and emission parameters such as nitrogen oxides (NOx), carbon monoxide (CO), total unburned hydrocarbons (HC), sulfur dioxide (SO 2) and smoke opacity from engine operation with TF and TF-diesel mixed fuels were experimentally investigated and compared with diesel fuel. It is concluded that a mixture of waste tire pyrolysis oil TF5, TF10, TF25, and TF35 can be efficiently used in diesel engines without engine modifications. However, mixtures TF50, TF75, and TF100 produce high CO, HC, SO 2, and smoke emissions.
The effect of molar ratio [Fe] / [Mn], promoter, optimal promoter loading, and calcination conditions on the catalytic performance of iron-manganese catalysts for Fisher-Tropsch (FTS) synthesis was investigated. It was found that the 50% Fe / 50% Mn catalyst promoted with 6 wt.% K is the optimal catalyst for converting synthesis gas into hydrocarbons, especially light olefins. The effect of calcination behavior and operational conditions on the catalytic performance of the optimal catalyst was investigated. The results showed that the best operating conditions are a molar feed ratio of H 2 / CO = 2/1 at 280 ° C and GHSV = 1400 hours - 1 under 3 total bar pressure. Catalyst characterization was carried out using X-ray diffraction (XRD), temperature Program reduction (TPR), thermal gravimetric analysis (TGA), and differential scanning calorimetry (DSC), and N 2 adsorption-desorption measurements such as Brunauer-Emmett-Teller (BET) and Barrett – Joyner – Halenda (BJH).
This study focuses on enhancing CO 2 adsorption by modifying limestone with acetate solution under pressurized carbonation conditions. Multi-cycle tests were conducted in a pressurized carbonation/calcination reactor system at different temperatures and pressures. Pore structure characteristics (BET and BJH) were measured as a supplement to reaction studies. Compared to raw limestone, modified sorbents show a significant increase in CO 2 adsorption under the same reaction conditions. The highest CO 2 adsorption was obtained at 700 ° C and 0.5 MPa, with an increase of 88.5% over limestone at 0.1 MPa after 10 cycles. N 2 adsorption and SEM characterization of sorbent structure confirmed that, compared to modified sorbents, effective limestone pores were significantly hindered by sintering, inhibiting easy access of CO 2 molecules to active and unreacted CaO sites. Morphological and structural characteristics of modified sorbents did not reveal significant differences after several cycles. This explains the superior performance of CO 2 adsorption under pressurized carbonation. Even after 10 cycles, the modified sorbent still achieves CO 2 adsorption of 0.88.
This short communication reports the assessment of the oxidation process of jatropha oil fatty acid methyl ester samples delivered to Rancimat (EN 14112) and PetroOXY oxidation method (ASTM-D7545). Fourier Transformed Infrared Spectroscopy (FTIR) was used to evaluate the degradation products of FAME resulting from accelerated oxidation, following the carbonyl band area (~1740 cm -1) of the samples at different oxidation times. Our results show that the oxidation level of jatropha oil FAME, using the Rancimat method, follows the same pattern as samples oxidized using the PetroOXY method.
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