Horizontal Furnace Research Articles

Pyrolysis of sawdust in a horizontal tube furnace: Effects of temperature and heating rate on product composition

The abundant sawdust waste from the timber production industries in Malaysia can be a potential biomass feedstock for pyrolysis process. However, the understanding of product composition and bio-oil quality from sawdust pyrolysis remains limited in Malaysian’s context. In this study, pyrolysis of sawdust was conducted in a horizontal tube furnace to investigate the effects of temperatures (400-550 °C) and heating rates (10-20 °C/min) on the composition of products, quality and properties of bio-oil. According to Gas chromatography (GC) analysis, phenol group appears to be the major compound in the bio-oil. The chemical components of bio-oil were found to be richer at lower reaction temperatures (400-450 °C), where it showcased the presence of phenols, ketones, carboxylic acids, furans, aldehydes, alkenes, alcohols, ether and amine. At increased reaction temperatures (500–550 °C), the process favoured the production of catechol (17%). The yield of bio-char decreased with increasing temperatures and heating rates due to the loss of volatile matter, and 400 °C proved to be the optimum temperature for maximum biochar yield. The biochar also displays porous structure, with increased adsorption capacity. Since the pyrolysis of sawdust could produce phenolic compounds, it appears to be a potential feedstock for biomass pyrolysis.

Fire Protection of Steel Beam by OSB Claddings—A Fire Experiment and Numerical Models

ABSTRACTThis paper presents the results of a standard fire resistance test of a loaded steel beam in a horizontal furnace. The beam was tested in three configurations: (1) unprotected, (2) protected with a single 22 mm layer of oriented strand board, and (3) protected with a double layer of the same cladding. The study also describes the development of a model in Fire Dynamics Simulator to predict the thermal conditions in the furnace and to observe the temperature trends on the beam surface, on the cladding, and at various depths in the cladding. A comparison between calculated and measured temperatures showed good agreement for the unprotected beam. However, for the protected beams, the model underestimated temperatures after 15 and 30 min for the single‐layer and double‐layer protection, respectively. Several potential sources for the discrepancies are identified. The main reason lies probably in the model's inability to correctly account for the effect of gaps in the cladding joints. Future work will focus on improving the accuracy of the model by removing these identified limitations, with particular attention to the behavior of the cladding as a passive fire protection material.

High-Temperature Oxidation Behavior of Fe-10Ni Alloy in Air/Ar-H2-H2o Dual Atmosphere

The utilization of hydrogen is expected to achieve carbon neutrality. Solid Oxide Electrolysis Cell (SOEC) is gaining attention for hydrogen production. Each cell stack is connected by stainless tube, and SOEC is typically operated at high temperatures of 500 to 900°C. High-efficiency energy conversion can be achieved by operating at such high temperatures, however stainless tubes suffer severe degradation due to high temperature oxidation. The stainless tubes are exposed to a dual atmosphere of H2-H2O on the inside and air on the outside in SOEC system. A protective Cr2O3 scale is formed on the stainless tube in single air, but a thick Fe-rich oxide formation on the air side under dual atmosphere is reported. Hydrogen and water vapor on the H2-H2O side are considered to affect severe oxidation on the air side, but the details are not understood. It is difficult to evaluate the effect of hydrogen and water vapor by using Cr2O3-forming alloys because the oxide scale formed on the alloys is different. Fe-10Ni alloys is known to form similar oxide scale with or without water vapor. In this study, high-temperature oxidation behavior of Fe-10at.%Ni alloy in single air and air/Ar-H2-H2O dual atmosphere was investigated, and the effect of hydrogen and/or water vapor was evaluated. Fe-10at.%Ni alloy was prepared by Ar-arc melting and the alloy ingot was hot rolled to approximately 1.3 mm thickness. Samples (approximately φ20 mm × 1 mm thick) were cut from homogenized alloy sheets and ground to a 4000-grit using SiC abrasive paper. The samples were then polished using 3-μm diamond paste, followed by ultrasonic cleaning in acetone. High-temperature oxidation tests were conducted using a horizontal furnace, as illustrated in Fig. 1. The sample was mechanically clamped using bolts and nuts, and gaskets used in SOFC were used to seal the sample tightly to the sample holder. During the oxidation tests, Ar gas was continuously flushing inside of the quartz tube to avoid degradation of the sample holder. Samples were heated to 800°C at a rate of 10°C/min in Ar, and flowing gas was immediately switched air or Ar-H2-H2O after heating to 800°C, followed by isothermal oxidation in single air and air/Ar-H2-H2O dual atmosphere for up to 16 h. The flow rate of air and Ar-H2-H2O was 25 ml/min. After the oxidation test, cross sections of oxide scale were observed by Optical Microscope and FE-SEM. The element distributions were analyzed by EPMA. Figure 2 shows cross-sectional FE-SEM images of air side after oxidation for 16 h in (a) single air and (b) air/Ar-10H2-10H2O dual atmosphere. An outer Fe oxide and subscale were formed on both atmospheres. From EPMA analysis, the outer scale consists of Fe2O3 and Fe3O4 in single air, and the subscale was also identified as Fe3O4. In dual atmosphere, FeO was formed in the outer scale in addition to Fe2O3 and Fe3O4, and the oxide in subscale was also FeO. Ni content at the alloy surface in dual atmosphere was found to be about 50 at.%, indicating that partial pressure of oxygen at alloy surface on the air side decreased by diffusion of hydrogen from Ar-H2-H2O side. Thus, the formation of FeO was possible in dual atmosphere. The thickness of the outer scale and the subscale was found to be thicker in dual atmosphere, and this was especially pronounced for the subscale. In the subscale region, many voids were observed, and the number of voids decreased in dual atmosphere. Additionally, large gap was formed in the outer scale in dual atmosphere. These results indicate that the dissociation of FeO occurred in dual atmosphere. Figure 3 shows the proposed model for oxidation behavior of Fe-10Ni in air/Ar-10H2-10H2O dual atmosphere. At the interface Ⅰ, FeO is reduced by the reaction FeO + H2 → Fe + H2O, resulting in outward Fe supply and the formation of H2O. The released Fe diffuses toward the outer scale surface and form a new oxide. H2O might diffuse inwardly and react with Fe diffused from the alloy substrate to form a new FeO at the interface II and in the subscale, resulting in a thickening of FeO below the gap and a reduction of voids in the internal oxide layer. Higher growth rate of the outer scale and subscale in dual atmosphere might be caused by additional outward Fe supply and H2O generation due to the FeO dissociation. Figure 1

Experimental study on char nitrogen conversion characteristics during char combustion process in pressurized O2/CO2/H2O atmosphere

Pressurized oxy-fuel combustion is an advanced CO₂ capture technology with potential applications in coal-fired power generation. In this study, the conversion behavior of char-nitrogen under pressurized oxy-fuel combustion conditions was investigated using a horizontal furnace across a pressure range of 0.1–1.3 MPa in an O₂/CO₂/H₂O atmosphere. The influences of pressure, gas composition, and residence time on nitrogen conversion were examined, and key factors affecting nitrogen transformation pathways were identified. Results indicated that elevated pressures favored NH₃ formation while inhibiting the formation of NO and NO₂, particularly at pressures above 0.7 MPa. Under pressurized conditions (0.7/1.3 MPa), increasing the O₂/CO₂ ratio further suppressed the conversion of char-N to NO, a contrast to behavior observed at atmospheric pressure. X-ray photoelectron spectroscopy analysis revealed a preferential consumption of nitrogen species, such as pyridinic and pyrrolic nitrogen, with pressurization enhancing the depletion of protonated nitrogen. Furthermore, an increased O₂/CO₂ ratio promoted the conversion of nitrogen oxides and other nitrogenous forms.

RSM-based co-gasification of palm oil decanter cake and sugarcane bagasse: Syngas production and biochar characteristics

The production of syngas (CO + H2) and biochar from biomass waste co-gasification promotes sustainable energy while addressing environmental remediation challenges. This study investigates the co-gasification of palm oil decanter cake (PODC) and sugarcane bagasse (SB) to optimize syngas production and obtain biochar in a fixed bed horizontal tube furnace reactor. Operating variables, including temperature (700–900 °C), biomass ratio (30–70 wt%), and particle size (0.25–2 mm), were optimized using Response Surface Methodology with the Box-Behnken design. Characterization analyses including Brunauer-Emmett-Teller (BET), Fourier Transformed Infrared (FTIR), and Field Emission Scanning Electron Microscopic (FESEM) analyses were conducted on the biochar. The optimal conditions yielded a syngas volume of 41.5 vol% and a biochar of 0.3 wt%, achieved at 900 °C temperature, 42 wt% PODC biomass ratio, and 2 mm particle size. BET analysis revealed a mesoporous structure biochar with surface area of 398.55 m2/g, pore volume of 0.13 cm3/g, and pore diameter of 6.49 nm. FTIR analysis indicated the presence of hydroxyl groups, carbonyl groups, aromatic compounds, and hydrocarbon structures. FESEM analysis showed well-defined pore structures on the biochar surface, with EDX analysis confirming a dominant carbon content of 83.32 wt%. These findings substantially enhance sustainable approaches in energy production, agriculture, and wastewater treatment, while effectively tackling environmental issues associated with biomass waste.

Unlocking the thermoelectric potential of nanocrystalline magnesium selenide thin films grown by single stage horizontal tube furnace (SSHTF)

In this manuscript, the thin films of Magnesium Selenide (MgSe) were synthesized on a glass substrate using a single-stage horizontal tube furnace (SSHTF) which is supposed to be the simplest and a cost-effective approach. Before the deposition of thin films, the substrate was cleaned using standard methods. A pellet was formed by taking an equal ratio (1:1) of magnesium (Mg) and selenium (Se) powders and then evaporating them at 700oC for 1 h. The flow rate of nitrogen gas (100 SCCM) was maintained during the deposition process to avoid unwanted oxygen. A number of samples were synthesized by varying the source to substrate distance, and some representative samples are chosen for this study. The post-growth samples were characterized using XRD, SEM, and Raman Spectroscopy. The thermoelectric potential of all samples was tested by a home-developed Seebeck system. We have observed some promising values of the Seebeck coefficient (7.175 × 10−5 V/°C) and power factor (6.35 × 10−8 Wm−1oC−2) at optimized source-to substrate distance. These encouraging results will open the door for MgSe-based thermoelectric research and further explore its power generation potential in the future.

Experimental study on high temperature gaseous hydrogen fluoride corrosion of boiler water-cooled wall pipes

ABSTRACT Hydrogen fluoride (HF) corrosion of boiler water-cooled wall pipes at high temperature hinders the co-disposal of fluorinated hazardous wastes and coal by combustion. In this paper, common water-cooled wall pipes (15CrMoG and 20G) were utilized to perform gaseous HF corrosion experiments at high temperature on a horizontal tube furnace. The effects of temperature on HF corrosion of different water-cooled wall pipes in 0.2% HF were investigated. Corrosion kinetics curve was obtained by calculating the mass increase due to corrosion. The microscopic morphology and physical phase composition of water-cooled wall pipes after HF corrosion were analyzed. The corrosion resistances of the two water-cooled wall pipes decrease with increasing the temperature. The corrosion weight gain curves of 15CrMoG and 20G at 550 ℃ are ΔW 1.9144 = 0.2100t and ΔW 1.8356 = 0.1344t, respectively. The average corrosion rates of 15CrMoG and 20G are 0.0177 and 0.0125 mg/(cm2·h), respectively. The corrosion resistance of 15CrMoG is superior compared to 20G. The HF corrosion at high temperature consists of non-alternating fluorination and oxidation of the metal matrix. This study is of great significance for the protection of boilers with HF corrosion at high temperature.

Study on molten salt on torrefaction and subsequent pyrolysis of elm branches

Torrefaction was a promising pretreatment for enhancing biomass properties, and molten salt torrefaction could achieve superior torrefaction benefits at equivalent temperatures. To explore the difference between molten salt torrefaction (MT) and conventional torrefaction (CT) and the effect of which on the subsequent pyrolysis of biomass, torrefaction experiments at 260 ℃ and pyrolysis experiments were conducted in a horizontal furnace, a thermogravimetric mass spectrometry (TG-MS) and a pyrolysis gas-chromatography mass-spectrometry (Py-GC-MS), respectively. The results showed that the O/C of washed MT sample (MTw) decreased by 13.89 % and the volatile content decreased by 14.56 % compared with washed CT sample (CTw). Concurrently, the MTw sample demonstrated the highest calorific value and largest specific surface area among the samples. The maximum weight loss rate of MT sample during subsequent pyrolysis increased. In comparison with CT, MT could decrease the pyrolysis activation energy. Furthermore, MTw sample produced more H2 and CH4, while simultaneously less CO2 and CO during pyrolysis compared with CTw. The bio-oil derived from the MTw sample exhibited the lowest relative content of acidic compounds and the highest relative content of aromatic compounds, signifying its enhanced quality.

Preparation of 97% pure nickel-cobalt alloy from waste Ni-MH batteries by using waste glass as a fluxing agent

With the e-waste growing rapidly all over the globe due to growing demand of electronics, smartphones, etc., coming up with an efficient and sustainable recycling process is the need of the hour. The present work reports a novel and sustainable process of manufacturing Ni alloy by bringing together three major waste streams such as waste Ni-MH batteries, e-waste plastics, and waste glass. The chosen temperature (1550 °C) favours the reduction of nickel-oxide by e-waste plastic as the reductant and sends rare earth elements present in the waste Ni-MH battery as oxide mixture to the slag phase. Waste glass powder used in this process functions as the fluxing agent, hence not requiring any additional flux. The reduction mechanism is gas-based, controlled mainly by hydrogen and carbon monoxide gases released as a result of decomposition of e-waste plastic as reaction commenced from cold zone (∼300 °C) to hot zone (1550 °C) in the horizontal tubular furnace. Formation of nickel alloy and enrichment of slag with mixture of rare earth oxides were confirmed by XRD, SEM-EDS, and Rietveld refining analysis performed on the XRD spectra of slag phase. ICP-OES (Inductively coupled plasma optical emission spectroscopy) and LIBS (laser induced breakdown spectrometer KT-100S) confirmed the high metal content in the alloy, thereby emphasizing the purity (∼98%) which is close to the composition of nickel super alloy. A maximum of 61% by weight REO enrichment was achieved in the slag phase, having La2O3:44.6%, Pr2O3:14.8%, and Nd2O3: 1.6% under optimised experimental conditions (1550 °C, 15 min, and 20% waste glass powder). This scientific investigation evinces a promising route for efficient utilisation of waste streams emanating from e-waste, thereby devising a sustainable recycling technique and protecting the environment, too.

Optical transmittance range of High-Temperature stable phase germanium dichalcogenide (GeS2) single crystal grown by the Bridgman method

A high-temperature (HT) stable phase germanium dichalcogenide (GeS2) was grown in an evacuated quartz ampoule to investigate its transparency range. First, as a starting material for the crystal growth of HT-GeS2, GeS2 glass containing HT-GeS2 crystals was synthesized using our previously improved process for synthesizing polycrystalline sulfide compounds in a conventional horizontal furnace. The HT-GeS2 crystal was grown using the Bridgman method under a temperature gradient of 20–30 °C/cm. The grown HT-GeS2 single crystal was easily cleaved along the growth direction, and this cleaved surface was identified as the (001) face using X-ray diffraction (XRD). Single-crystal XRD analysis confirmed the growth of an HT-GeS2 single crystal with a monoclinic structure (space group P21/c) and lattice parameters of a = 6.7061(4) Å, b = 16.0877(13) Å, and c = 11.4242(11) Å, and β = 91.069 (8)°. The optical transmittance spectra of the HT-GeS2 single crystal were measured in the visible and infrared (IR) regions, revealing a transparency range of 0.36–22.5 μm. Differential thermal analysis revealed the melting point of HT-GeS2 as 841 ± 1 °C. The HT-GeS2 single crystal is expected to be a new candidate for IR optical crystal.

Process exploration for scale melting and solidifying of municipal solid waste incineration (MSWI) fly ash by horizontal cyclone melting furnace

This study used the horizontal tubular heating furnace to explore the melting potential of circulating fluidized bed (CFB) incinerator fly ash and mechanical grate furnace (MGF) incinerator fly ash. The horizontal cyclone melting furnace was then built to explore further the feasibility of scale melting of MSWI fly ash. The melting characteristic temperature, amorphous content, and heavy metal leaching concentration characterized the melting potential and solidification effect of MSWI fly ash. The experimental results show that the amorphous content of CFB fly ash after melting is up to 92.37%, and the volatilization rate of heavy metals Zn, Pb, and Ni does not exceed 30%. MGF fly ash exhibits the “sintering into shells” phenomenon during heating, and the leaching concentrations of heavy metals Pb in the sintered products still exceed the standard limits. In addition, the volatilization rates of heavy metals Cu, Zn, Cd, Pb, Cr, and Ni in Slag II are above 50%, and the volatilization rate of Cr reaches 85%. So, slag’s amorphous content also affects heavy metals’ volatilization rate. The MSWI fly ash melting characteristic temperature decreases with the decrease of alkalinity value. When the alkalinity value drops to 0.6, the melting characteristic temperature reaches its lowest value. Mixing 80% CFB fly ash or 50% MGF bottom ash into MGF fly ash can significantly enhance the melting potential to reduce hazardous waste. When using the horizontal cyclone melting furnace to process MSWI fly ash on a large scale, MSWI fly ash achieves an excellent melting effect with an amorphous content of over 93% at the positions of the furnace middle section, inner tail cone, slag discharge outlet, and flue gas outlet. The fly ash particles are in motion in the melting furnace, so the particle size distribution affects the melting effect of MSWI fly ash.

Effect of furnace temperature and oxygen concentration on combustion and CO/NO emission characteristics of sewage sludge

Addressing the growing energy crisis, the development and utilization of solid waste have become a critical research areas. Sewage sludge, rich in organic matter, can serve as an alternative fuel to coal. This study employs a thermogravimetric analyzer to investigate the combustion characteristics of sewage sludge at heating rates of 10, 20, and 40 °C/min. Additionally, a horizontal tube furnace is utilized to analyze the CO and NO emission characteristics during sewage sludge combustion at varying oxygen concentrations and temperatures. Results indicate that at a constant gas velocity, the primary factor influencing combustion characteristics and CO/NO emissions is the composition difference. Higher furnace temperatures lead to lower CO generation and increased combustion efficiency. The conversion of coke-N to NO rises with increasing temperature. Moreover, higher furnace temperatures decrease the conversion of fuel-N to NO. Increasing oxygen concentration reduces the ignition concentration limit of sewage sludge. The lowest NOx emissions were recorded at an oxygen concentration of 21 vol%. This study provides essential data for reducing coal consumption and enhancing the safe and efficient treatment of sewage sludge.

Comparative Study of Heat Transfer Simulation and Effects of Different Scrap Steel Preheating Methods

The materials charged into a converter comprise molten iron and scrap steel. Adjusting the ratio by increasing scrap steel and decreasing molten iron is a steelmaking raw material strategy designed specifically for China’s unique circumstances, with the goal of lowering carbon emissions. To maintain the converter tapping temperature, scrap must be preheated to provide additional heat. Current scrap preheating predominantly utilizes horizontal tunnel furnaces, resulting in high energy consumption and low efficiency. To address these issues, a three-stage shaft furnace for scrap preheating was designed, and Fluent software was used to compare and study the preheating efficiency of the new three-stage furnace against the traditional horizontal furnace under various operational conditions. Initially, a three-dimensional transient multi-field coupling model was developed for two scrap preheating scenarios, examining the effects of both furnaces on scrap surface and core temperatures across varying preheating durations and gas velocities. Simulation results indicate that, under identical gas heat consumption conditions, scrap achieves markedly higher final temperatures in the shaft furnace compared to the horizontal furnace, with scrap surface and core temperatures increasing notably with extended preheating times and higher gas velocities, albeit with a gradual decrease in heating rate as the scrap temperature rises. At a gas velocity of 9 m/s and a preheating time of 600 s, the shaft furnace achieves the highest waste heat utilization rate for scrap, with scrap averaging 325 °C higher than in the horizontal furnace, absorbing an additional 202 MJ of heat per ton. In the horizontal preheating furnace, scrap steel exhibits a heat absorption efficiency of 35%, whereas in the vertical furnace, this efficiency increases notably to 63%. In the vertical furnace, the waste heat recovery rate of scrap steel reaches 57%.

Deep Intergranular Fluoride Attack by High-Temperature Corrosion on Alloy 625 by LiF in Air at 600 °C

In most chemical and high-temperature processes, metals are exposed to temperature gradients which, in turn, affect the extent of corrosion phenomena. In this study, a long, continuous strip of alloy 625 was exposed to lithium fluoride in a temperature range of 50–600 °C, air environment. The hottest section of this strip was analyzed as a coupon and compared with two other coupons which were exposed isothermally. One of the isothermal exposures was carried out in a tube furnace, and the other one was in a vertical furnace. Oxygen had three different kinds of access to these three coupons, which, in turn, affected the corrosion process. In order to limit the access of oxygen, a long column of lithium fluoride was used in a vertical furnace. The results of the isothermal exposure showed that more access of oxygen in a horizontal tube furnace facilitated the fluoride ingress to a great extent. However, a long sample exposed to a temperature gradient suffered more corrosion attack than the isothermal coupon, under the same LiF load in the vertical furnace. This was associated with the reduction of oxygen at a larger cathode area reaching into colder regions in Inconel 625 strip. Increased oxygen reduction also increases the efficiency of an inner anode at the hottest section, causing the observed rapid intergranular fluoride uptake. The study proposes a mechanism explaining these observations.

An experimental and density functional theory investigation of the influence of HZSM-5 on pyrolysis oils produced from vanillin, a model lignin compound

Lignin, as a renewable energy source, has attracted much attention due to its high valorization potential. Due to the complex composition of lignin, vanillin, an important intermediate of lignin, was chosen as a model compound in this study. The study examined the influence of the HZSM-5 molecular sieve on the quality of pyrolysis oils during the catalytic pyrolysis of vanillin at 600 °C using a horizontal tube furnace and Py-GC/MS analysis. The results revealed that the HZSM-5 catalyst significantly increased the yields of toluene, guaiacol, and 4-hydroxyisophthalaldehyde by 2.49 %, 19.26 %, and 1.8 %, respectively, whereas reducing the contents of phenol and 3,4-dimethoxyphenol by 6.01 % and 3.79 %, respectively. These findings indicate that the HZSM-5 molecular sieve effectively improves the quality of pyrolysis oils during the catalytic pyrolysis of vanillin. The evolution of the main functional groups in the pyrolysis of vanillin was analyzed using an in situ diffuse reflectance infrared Fourier transform spectroscopy. The addition of HZSM-5 promoted the cleavage of oxygen-containing functional groups and the generation of aromatic hydrocarbons during the pyrolysis of vanillin. Furthermore, the pyrolysis reaction pathways of vanillin were simulated under the B3LYP/6-311 g (d, p) basis set using the density functional theory. The acidic sites of HZSM-5 interacted with vanillin via the hydrogen bonds that affected the energy barriers of the pyrolysis reaction pathways of vanillin. HZSM-5 inhibited the generation of phenol and 3,4-dimethoxyphenol by increasing the energy barriers by 32.95 and 31.03 kJ/mol, respectively; however, HZSM-5 promoted toluene production by decreasing the energy barrier by 37.38 kJ/mol. The effects of HZSM-5 on the products in the simulation results were consistent with the experimental results.

The release and migration mechanism of arsenic during pyrolysis process of Chinese coals

Special attention was drawn to the heavy metals contained in coal, due to it will cause harm to the environment during coal processing and utilization. The sequential chemical extraction of Shanxi coal (SX coal) and Wulanchabu coal (WLCB coal) was carried out to investigate the distribution of arsenic (As) in coals. Two raw coals were pyrolyzed at 300–900 °C in horizontal tubular furnace to investigate release behavior of As during pyrolysis process. The results showed that As in SX coal mainly existed in aluminosilicate-bound state (40.25%) and disulfide-bound state (32.51%), followed by carbonate-bound state and organic-bound state. The As in WLCB coal mainly existed in aluminosilicate-bound state (62.50%), followed by disulfide-bound state (19.10%). The As contents of water-soluble, ion-exchange and residue states in the two coals were less than others. The modes of occurrence of As had great influence on its volatilization behavior. As in organic part was easy to volatilize at low temperature. Sulfide-bound state would escape with the decomposition of pyrite. Because SX coal contained higher organic state and sulfide-bound state, the volatilization rate of As was higher than WLCB coal at any temperature, and the difference was more obvious at low temperature. In addition, FactSage simulation value was basically consistent with the experimental value.

Correlation analysis and predicting modeling of pyrolysis gas based on landfill excavated waste pyrolysis characteristics

The contribution of excavated waste to waste management is multifaceted, including minimization, non-hazardous disposal, access to useable land resources, improved waste management techniques and public environmental awareness, consistent with recent circular economy initiatives. Pyrolysis can be converted into tar, pyrolysis gas and char with recyclable utilization, enriching the application of pyrolysis technology in the field of excavation waste. In this study, the pyrolysis system includes horizontal tube furnace, gas collection device and Micro GC. The excavated waste was pyrolyzed at a temperature of 500∼900 °C with a heating rate of 10 °C/min. Pyrolysis gases include H2, CO, CO2, CH4, C2H4, C2H6 and C3H8. Pyrolysis was divided into four stages, the main decomposition range is 230∼500 °C, with a weight loss rate of 68.49% and a co-pyrolysis behavior. As the temperature increases, the tar and char decreased and the gas production increased significantly, and the pyrolysis gas reached 47.02% at 900 °C. According to Pearson correlation coefficient analysis, the generation of H2 and CO is positively correlated with temperature. Therefore, the target products can be influenced by changing the parameters, when considering the practical utilization of the excavated waste pyrolysis products. On this basis, the prediction models were built by polynomial fitting method. This model can reduce the experimental exploration cycle, reduce the cost, and accurately predict the pyrolysis gas, which has practical guidance for the application of pyrolysis industry, and provides a theoretical basis for the resource recycling and energy recovery of landfill.

Feasibility of co-disposal of lignite and eucalyptus wood in coal-fired power plants: thermogravimetric characterization, typical gaseous pollutant emission characteristics, and economic analysis

ABSTRACT Energy issues are becoming increasingly prominent, and biomass blending in coal-fired power plants can improve combustion performance and reduce gaseous pollutant emissions, thereby improving economic efficiency. In this study, a thermogravimetric analyzer, a horizontal tube furnace, and an infrared flue gas analyzer were used to investigate the combustion behavior and gaseous pollutant emissions of the co-combustion of LC and EW. The results show that blending EW into LC cofiring can inhibit the release of volatile matter and promote the decomposition of fixed carbon and lignin simultaneously. The HHV of EW (15.88 MJ/kg) reaches 63.7% of LC’s (24.90 MJ/kg), indicating EW has a high energy utilization value. With increasing combustion temperature, the average value of CR S increased from 47.09% to 59.94%, and the average value of CR Cl increased from 26.15% to 52.15%, leading to a significant increase in SO2 and HCl emissions. The decrease in combustion temperature slightly promoted the release of N (CR N increased from 11.76% to 14.45%). The results of the economic analysis show that the cost of CaO and NH3·H2O used for removing gaseous pollutants decreased the most, and the economic efficiency increased the fastest to 14,000 RMB/day when the EW blending ratio increased from 10% to 20%.

A Comparative Study of the Oxidation Behavior of Hot-Rolled Steel established from Medium and Thin Slabs oxidized in 20% H2O-N2 at 600-900°C

This study focuses on the oxidation behavior of oxide scale on hot-rolled steel from a Thailand steel industry. Hot-rolled steel established from the medium and thin slabs was studied. The oxidation behavior was conducted in a horizontal furnace with 20%H2O-N2 to simulate steel oxidation during the hot rolling line. The scale was formed at a temperature range of 600-900°C for 30, 60, and 90 min. The scale morphology can be seen via Scanning Electron Microscope (SEM-EDS). The oxide phase was investigated via X-Ray Diffraction (XRD). The results show that iron oxides such as hematite (Fe2O3) and magnetite (Fe3O4) were produced on the studied steel. The oxidation behavior of the studied steel was followed by a parabolic law. The mass gain increased with increasing temperatures. The steel established from a medium slab exhibited a lower oxidation rate than the steel established from a thin slab. The reason for this could be the high amount of oxide containing silicon at the steel-scale interface, which promoted the oxidation resistance of the steel established from the medium slab. The influence of different slab types and its alloying elements was studied to comprehend the oxidation behavior. As a result, the alloying element in the hot-rolled steel was controlled in the design process.

Influence of Mn composition on structural, optical, dielectric and magnetic properties of synthesized Cd1−xMnxTe (x = 0.08 & 0.12) polycrystals

Synthesis of polycrystalline CdMnTe using a homemade horizontal furnace: influence of Mn on structural, optical, dielectric and magnetic properties.