Furnace Material Research Articles

Utilization of biomass waste for activated carbon production by steam gasification in a rotary reactor: experimental and theoretical approach

In order to produce cheap activation carbon for dioxin adsorption in waste incinerator, waste plywood, pinewood, and coconut shell were used as raw materials to produce activated carbon via steam gasification on a lab-scaled rotary reactor. The influence of temperature, steam flow rate, and activation time on activated carbon yield and properties was investigated. Experimental results show that at 800 years, with 30-min activation time and steam/char ratio equal to 2, the yield of plywood activated carbon reached 60.5%, which was much higher than pinewood. The iodine adsorption value was 943 mg/g, which is close to pinewood. The pore structure analysis results show that the activated carbon derived from pinewood and plywood is similar. The pores with diameter of 2–5 nm were well developed, which was suitable for dioxin adsorption in waste incinerator. In the end, the computational fluid dynamics (CFD) and discrete element method (DEM) were used for modeling and optimization of the rotary furnace. Calculation results show that internal friction between the particles or the degree of anisotropy of the particles will cause the particles in the furnace to form a larger accumulation inclination, which benefits the mixing of the material in furnace. The results show that both the Eulerian-Eulerian two-fluid method and the DEM can simulate the movement of particles in the rotary furnace.

Temperature distribution simulation on Aluminum incineration furnace using Autodesk simulation mechanical CFD 2018

Used lubricating oil is one of the liquid wastes which is produced by an industrial machine or private vehicle machine. Lubricating oil is a waste that is produced by machines in both large industrial and private vehicle engines. This research aims to examine the process of manufacture and the system of oil-fueled crucible stoves, and simulated the temperature at aluminium melting furnace by doing some form of design testing; selection of furnace material using carbon steel, brick, plate; furnace modeling which has three parts of crucible, fireproof stone and lids where the three parts have different sizes and uses of each, then set the simulation as what we aim to such as the temperature distribution where the air temperature reached 40°C heat source from combustion 1200°C. From the combustion, the velocity value obtained is 0.5 in/s, distribution at crucible is 749°C. In conclusion, the used oil smelting furnace can melt used aluminium metal, so that the used metal oil melting furnace can be used in the home industry to recycle used aluminium metal.

Thermal behaviour of ladle slag mortars containing ferrochrome slag aggregates

Concretes, depending on their application, may be exposed to elevated temperatures during their lifetime, especially when placed near or in a furnace or during an accidental fire. The thermal stability of alkali-activated mortars and hydrated mortars prepared using ladle slag and two different aggregates was studied. A commercial calcium aluminate cement was used as a comparison for the properties after exposure to temperatures up to 1000°C. All samples were characterised and analysed through a strength test, dilatometric analysis, thermogravimetric analysis, ultrasonic pulse velocity and scanning electron microscopy. The hydrated ladle slag mortars exhibited properties similar to or better than the commercial calcium aluminate cement, while the alkali-activated ladle slag's thermal properties were inferior to the hydrated ladle slag mortars. The tests also showed that the use of ferrochrome slag aggregates in hydrated ladle slag mortars exhibited similar properties to those using sand aggregate mortars. The damage behaviours of the mortars were dependent on the temperature-induced dehydration, dehydroxylation and thermal incompatibility between the paste and aggregates. The results from this study specify the possibilities of using 100% industrial by-product-based mortar and near-zero carbon dioxide emissions as a fire-resistant material in furnaces, buildings and fireplaces.

Analysis of high temperature oxidation behaviour of SS316 by Al2O3 and Cr2O3 coating

The main objective of this work is to evaluate the oxidation behavior of super heater material which is used in the High temperature application such as super critical boiler. High temperature application operates at elevated temperature range above 700 °C and 750 °C. At elevated temperature, oxidation occurs surface of metal which leads to failure of material. This turns the metal to corrode which interrupts and decrease its functionality of plant. Hence, the selective super heater material (SS316) is selected for this work. High temperature oxidation behavior is analysed by testing the material in tubular furnace in air environment at 700 °C and 750 °C. The material is tested in the tubular furnace by arranging the specimen in an order like without coating of metal surface, second one is with Aluminium oxide coating of metal surface and third one is Chromium oxide coating of metal surface. After that the tested specimens are characterized by SEM, EDAX. From that results suitability of the metal for high temperature application in power plant is recommended.

Effect of additives concentration on pelletization of high grade hematite

The pelletization process can convert the iron ore fines (<150 µm) to improved feed material for blast furnaces. The process involves two steps, the “green pellets” formation with the addition of additives like, bentonite, anthracite coal and limestone to enhance the agglomeration phenomena. And then the pellets undergo heat hardening (Induration) process, to attain appropriate mechanical resistance and metallurgical characteristics required for the iron making facilities. The proportion of additive plays comparatively important role in a pelletization process starting from green pellet to fired pellet and then up to pellet reduction.The iron ore fines (Fe: 64% and LOI: 2.86%), anthracite coal, bentonite and limestone are taken as the pellet feed material. The aim of the present work is to investigate the effect of additives (bentonite, limestone and anthracite coal) variation (0.2, 0.5, 0.7 and 1%) on the physical, chemical and mineralogical characteristics of fired pellets prepared from high grade hematite fines. The physical properties such as cold compressive strength, porosity; chemical composition and microstructure of the fired pellets are compared and corroborated the findings.

Corrosion mechanism of spray refractory in COREX slag with varying basicity

Bauxite-based spray refractories typically exhibit excellent mechanical strength and wear resistance, and have been widely used as lining materials in various industrial furnaces for many years. However, smelting reduction ironmaking in the COREX-produced slag carried out under a gas flowing at a high speed causes refractory corrosion at high temperature. Herein, Al2O3–SiO2–CaO spray refractories were fabricated, and corrosion tests were conducted in an air atmosphere using the formulated COREX slag by varying the slag basicity from 0.5 to 1.0. The mechanism underlying the corrosion between the fabricated spray refractories and formulated COREX slag was investigated via X-ray diffraction, scanning electron microscopy (backscattered electron image and energy-dispersive X-ray spectroscopy), and thermodynamic simulations to establish a new corrosion model. The results showed that after sintering at 1300 °C, the prepared specimens contained corundum, mullite, and anorthite as the major crystalline phases. The reaction and penetration layers were observed from the surface to the interior of the specimens after corrosion. A high-melting-point phase, Mg(Al,Fe)2O4 spinel layer, was generated at the slag–refractory interface, which effectively protected the specimens from further interaction with the molten slag, and afforded better corrosion resistance. The reaction layer corroded due to the phase conversion into the Ca2Al2SiO7 in the matrix. The thermodynamic simulation results of the interaction between the slag and refractory were consistent with those of the corrosion test. The total corrosion depth of the specimen was optimum when the slag basicity was 0.9. This study investigates the optimal performance environment of the spray refractory inside the COREX and provides an effective guide for designing the phase composition of related refractories.

Design Modification of Greenhouse Effect Solar-Hybrid Rack Type Dryer

Hybrid solar-type rack dryers are modified to improve efficiency and to save the drying energy. Modifications are made to the main components, namely; furnace and heat exchanger. The dimension of dryer was 1.8 m length, 0.7 m width and 1.8 m high. The dryer was equipped by 22 racks with dimension of 0.5 m x 0.65m. The furnace was modified to a cylindrical shape instead of rectangular shape and was designed with optimization of heat utilization and comfortable to be operated. To reduce heat loss, the wall of furnace was designed contact directly the drying room. The furnace material was iron galvanized plate with a thickness of 2 mm. The foregoing design of heat exchanger was tube bank type with horizontal fins attached on tubes. In this research, the adoption of vertical fins has enlarged the heat transfer area and increase the effectiveness of heat exchanger. The smoke flow from the combustion chamber of furnace was directed at the opposite side of the ambient air inlet for drying, so that smoke does not enter the drying chamber.

Presence of magnesium-alumina spinel in forsterite ceramics and its influence during sintering and on resulting properties of fired body

The main objective of this paper is to describe the creation and behaviour of magnesium-alumina spinel (MA-spinel) phase from raw materials mixtures in forsterite refractory and its influence on resulting physical properties and mineralogical composition of fired body. Forsterite ceramics is mostly used for its high refractoriness as a refractory material in kilns and furnaces and also in electrotechnical engineering for its high coefficient of linear thermal expansion for ceramic-metal joints. Currently, forsterite is not produced in the Czech Republic. The primary objective is to synthesize forsterite ceramics via solid-state reaction utilizing various raw materials used in industry with stoichiometric ratio of forsterite. The resulting properties of fired body will be determined using X-ray diffraction analysis for mineralogical composition, thermal dilatometric analysis and vacuum water absorption method for physical properties of fired body and refractoriness of pyrometric cones will be conducted.

The ash formation and attrition characteristics of an Indonesia lignite coal ash for a 550 MWe ultra supercritical CFB boiler

The Samcheok CFBC (circulating fluidized bed combustion) power generation plant, the world largest, consists of 4 units of 550 MWe USC (ultra-supercritical) CFB boilers, started operation since the end of 2016. The years’ operation proves that there lacks circulating material and low solid hold-up in the upper furnace when burning Indonesia coal with low ash content of 4.5%. To solve this problem, the present study studied the mass balance of the Samcheok CFB boiler by investigating the ash formation and attrition characteristics of the feed coal in the lab. The ash formation PSD (particle size distribution) proves that the burnout-produced fly ash and fragmentation-produced fly ash are not the main sources of the production of fly ash. The heterogeneity of specific chemical compositions of particles in terms of particle sizes is proved to be one of the key factors for determining the attrition rate. For large particles, SiO2 and Al2O3 compositions dominate and results in low attrition rate, while for small particles, Fe2O3 and CaO compositions dominate and results in high attrition rate. The fine particles produced due to attrition have very high Fe2O3 contents, indicating that the heterogeneity of chemical composition is enhanced due to attrition. These findings show good agreement with the phenomenon of the high content of Fe2O3 in fly ash in the CFB boiler.

Evaluation of the chemical and thermo-physical properties of locally aggregated kaolin-based refractory materials

There is a continuous demand for refractory materials to meet the increasing expansion of industries and plants. Local clay materials are being explored to augment the inadequate supply of refractory materials. This study therefore evaluated the suitability of locally aggregated kaolin as refractory material. The kaolin was aggregated from Ipinsa kaolin, termite hill materials and bentonite in the ratio 5:4:1 by mass. Chemical analysis carried out on the materials using Proton Induced X-ray Emission (PIXE) Equipment revealed that the kaolin aggregate had a composition of 37.22% alumina (Al2O3) and 51.93% silica (SiO2). The Ipinsa kaolin comprised Al2O3 at 43.05% and SiO2 53.91%, termite hill material (Al2O3 22.69%, SiO2 58.83%) and bentonite had 23.10% Al2O3 and 55.40% SiO2. It shows that Ipinsa kaolin can be used for refractory materials in furnaces, kilns and stoves while the aggregated clay can be used in applications requiring more superior refractory properties. The thermo-physical analysis of the aggregated clay revealed a bulk density of 1.84 g/cm3, apparent porosity 31.54%, linear shrinkage 4.00%, thermal shock resistance 40+ and refactoriness 1900 oC. The refractoriness indicated that the aggregated clay is also suitable for use as ceramic fibre within the temperature range of 1800 and 2000 oC.

THE CURRENT STATE OF RESOURCE AND ENERGY SAVING IN THE TECHNOLOGY OF PRODUCTION OF CARBON-BASED FILLER OF ELECTRODE PRODUCTS (REVIEW)

Advantages of application of electrocalciners to production of carboniferous fillers of the electrode industry are considered. The analysis of designs of electrocalciners is made, their advantages and disadvantages are given, and also the physical processes happening in them are described. The critical analysis of theoretical and experimental methods of research of physical processes at heat treatment of carboniferous materials in electric furnaces is carried out. It is shown that for development of resource-power effective technical solutions on modernization of the production technology of fillers in electrocalciner it is expedient to combine methods of mathematical modeling with separate pilot studies on the industrial equipment. It is shown that industrial using of resource-power effective technical solutions on modernization of the production technology of fillers in electrocalciner allows to receive the following indicators of efficiency: for anthracite calcinating electrocalciners the resource of work increased from 1 month to 6 months, and specific expenses of the electric power decreased by (50–100) kW·h/t; for graphitizing of oil coke electrocalciners the resource of work increased from 2 days till 1 year, and specific expenses of the electric power decreased more than by 1600 kW·h/t in comparison with classical technology. Bibl. 37, Fig. 7, Tabl 1.

Effect of Exposure Time, Lining Material and Plasma Gas on the Extraction of Aluminium from Waste by Smelting Reduction

Today’s world has experienced the change in the extraction of metal from its native ore to that from secondary resources. The ash and tailings are such secondary resources for extraction of aluminium. The present investigation shows the effect of furnace lining materials and plasma gas on the extraction of aluminium from the waste material during smelting reduction studies. A laboratory scale plasma arc furnace was used for the reduction studies of bottom ash, iron ore slime with charcoal. Experiments in hydrogen and nitrogen plasma environments were carried out inside magnesite and graphite crucible separately. The rate of reduced metal absorption by the liquid metal bath for a fixed time was determined. The output of aluminium through metal, slag and exit gas was calculated to establish a tentative mechanism of smelting reduction. Combination of nitrogen plasma and graphite crucible showed the optimum recovery level of reduced aluminium in metal. The high-temperature plasma could reduce highly stable oxides of waste materials, and the recovery of volatile aluminium in metal could be possible by using a metal solvent bath.

Development of High-Durability Substrates for Thermoelectric Modules

Thermoelectric modules with a π-structure were fabricated on four types of substrates, and their high-temperature durability was evaluated. A direct bonded aluminum (DBA) substrate was fabricated by using braze material in a vacuum furnace. In addition, an alumina substrate and DBA substrate each coated with pre-sintered Ag layers were fabricated by firing in a furnace in air after screen-printing of an Ag paste containing glass frit on alumina or DBA. Thermoelectric materials were mounted on these substrates by die bonding. In thermal durability tests, the percent increase in internal resistance of modules after 100 thermal cycles (cold side: Tc = 80°C; hot side: $$T_{\rm{h}} = 150{^\circ } {\hbox{C}} \Leftrightarrow 450{^\circ } {\hbox{C}} $$ was measured in air. After the durability testing, cross sections of the modules were prepared and analyzed by electron probe microanalysis and scanning electron microscopy. The percent increase in resistance of the module with pre-sintered Ag layers on an alumina substrate was 33%, and the percent increase in resistance of the module with pre-sintered Ag layers on a DBA substrate was less than 1%. These results demonstrated that, at high temperature in air, the percent increase in internal resistance at the interface between the thermoelectric materials and the metal electrode of a thermoelectric module can be significantly decreased by using Ag as an oxidation-resistant electrode and Al as a buffer layer for stress relaxation.

Poboljšanje efikasnosti tehnoloških procesa i smanjenje upotrebe resursa u industriji livarstva primenom BAT i BREF dokumenata

This paper illustrates all the transformation processes by which inputs (energy, water, input materials) are converted into a product / casting output through a series of activities and under the influence of a number of factors. Taking into account the Best Available Technique (BAT) data that a plant operator applies or plans to apply to reduce pollution, the following processes are presented: receiving raw materials and other materials, preparing materials, melting materials in furnaces and preparing for casting, tool making, mold making and sand preparation, casting, casting of castings and finishing of castings. The above processes are presented taking into consideration the analysis of BREF documents and comparison of the current situation, in the field with the BREF recommendations with a proposal for improvement, where necessary, and on the basis of the preparation of request for issuing an integrated (IPPC) permit, related to the use of the best available techniques in the production of gray, steel and ductile casting, which includes a description of the plant, production process and work process, information on the best available technique used to evaluate the process, and a comparison of the processes performed with respect to the relevant BAT.

Experience of Using Chromium Oxide Materials in Electric Glass-Melting Furnaces

Experience of using refractory materials based on chrome-oxide in electric glass-melting furnaces for fiberglass production is described. Prospects are noted for using chromium oxide refractories from the point of view of both the service reliability and the furnace campaign duration.

Simulation of the pressure drop across granulated mixtures using a coupled DEM – CFD model

The sinter process converts mixtures of iron ore, iron ore fines and fluxes into a fused aggregate (sinter) that is used as burden material in the blast furnace. The rate of this process is predicted by measuring the pressure drop across the green granulated mixture before ignition. A lower pressure drop corresponds with a higher permeability resulting in a higher sinter rate. The addition of fine material, such as concentrate or concentrate agglomerated into micropellets, to the sinter mixture affects the pressure drop. This study numerically predicts the pressure drop over several granulated mixtures in order to reduce the number of experimental measurements. The pressure drop was studied both experimentally using a pot grate and by coupled DEM (Discrete Element Method) – CFD (Computational Fluid Dynamics) simulations. The validation of the model was performed by comparing the measured and numerical values of the pressure drop across glass beads 3 and 6 mm in diameter respectively. The simulation of the pressure drop was extended to granulated mixtures that contain 0–40% concentrate or micropellets. DEM was also used to numerically simulate iron ore granules and relate their mechanical behaviour to particle size distribution, shape, friction coefficient, Young’s modulus and adhesion force.

Effect of the Temperature Treatment of Quartzite on the Lining Resistance of Commercial-Frequency Induction Crucible Furnaces

New temperature treatment conditions were proposed for the Pervouralsk quartzite PKMI-1V used as a lining material for commercial-frequency induction crucible furnaces. The new conditions allow conducting synthetic pig iron smelting at the temperatures in excess of 1450°C while maintaining high lining resistance.

Laser-Induced Superelasticity in NiTinol Stent Strut

Shape setting is a fundamental step of NiTi components manufacturing. It is undertaken for fixing programmed shapes and for optimizing both the shape memory and the superelastic properties of SMA. Conventional NiTinol shape setting is performed by constraining the material in furnace where it is heat treated completely, and thus local component functionalization is not allowed. Recently, it has been demonstrated the feasibility of fast laser shape setting of straight thin NiTinol wires to induce a superelastic behavior comparable to the commercial wires. This work reports the use of a laser beam for promoting a local superelasticity in a NiTi diamond-like strut. In details, the struts were cut from a cold worked NiTi thin tape, and then a focused laser heating was implemented just on the parts of the element in which the superelasticity is strictly required. Thermo-mechanical testing of the struts, after local laser process conditions, indicates that a laser beam scanning is suitable for provoking local microstructure modifications, which enables the superelastic functioning of the strut-like element. Scanning electron microscopy has shown that residual martensite variants, present in the cold worked material, disappear in the portion of the diamond elements where the laser beam passed.

Potash Erosion Resistance of Chromium-Containing Materials

Compared with the traditional entrained flow gasifier, coal catalytic gasifier has the advantages of low reaction temperature, high production efficiency and low energy consumption, but it also has higher requirements for potash erosion resistance. Chromium-containing material is commonly used as lining material for gasification furnaces. In this paper, potash erosion resistance of chromium-containing raw materials and products were respectively researched by using powder tabletting sintering and potassium vapor erosion method. The potash erosion resistance are characterized by XRD and SEM. The study show that:(1)There are obvious potassium salt deposition on the surface of chromium-containing raw materials and products after potash erosion experiment. Potash reacts with chrome-corundum and magnesium-chrome spinel to form K2CrO4,and reacts with chromium oxide to form K2Cr2O7at 750°C. (2)Potassium vapor enters into chromium-containing products through pores and leads to crack formation and volume change, which destroy the structure and reduce high temperature volume stability of material.

Effects of binder choice in converter and blast furnace sludge briquette preparation: Environmental and practical implications

Blast furnace and converter sludges are fine-grained waste materials characterized as dangerous waste with a negative impact on the environment. One way of recycling of such materials is briquetting followed by reuse of the material in the blast furnace. In the briquetting process, an important step is the choice of the binder suitable for manufacturing the briquettes with suitable mechanical properties. In this work, the effect of the binder choice (laundry starch UNIPRET, Portland cement) on the reduction of iron oxides in the assessed waste materials during thermal treatment (900, 1000, 1100 °C) is evaluated. Simultaneously, the effect of the binder choice on the amount and composition of the resulting waste gas was evaluated as well as its possible impact on the environment. The performed experiments proved the mutual relationship between the level of iron oxides to metal iron conversion, the binder content and retention temperature. Type of binder also affected the volume of the resulting waste gas. Factor analysis for mixed data (FAMD) proved that the resulting concentrations of the assessed hydrocarbons were correlated (apart from ethyne) and that they are closely associated with the binder applied. Conversely, the concentrations of ethyne, carbon monoxide and carbon dioxide were not associated with the binder but with the retention temperature. FAMD did not show any direct effect of final retention temperature on the amount of the rest of the resulting hydrocarbons. In comparison with the starch-containing briquettes, the cement-containing briquettes were also proved to lead to lower resulting concentrations of PAHs in the waste gas.