Prototype Furnace Research Articles

Experimental study and numerical modeling of the thermal behavior of an industrial prototype ceramic furnace: Energy and environmental optimization

This article focuses on the experimental and numerical study of an industrial prototype furnace intended for the production of ceramics in order to improve the energy efficiency and therefore optimize the fuel consumption and the corresponding carbon dioxide emissions. In order to understand the thermal behavior from which stems the energy efficiency of the experimental prototype, we establish in this work, a simplified modeling allowing to establish a mathematical model describing the thermal behavior of the furnace. The model is able to accurately predict the spatial and temporal distribution of the temperature at each point of the furnace to control the firing of the refractory product so that the final product is of good quality in terms of resistance and hardness. In addition, the power consumed by the prototype must be optimized in order to reduce energy and environmental consumption. In particular, this efficient technology has allowed us to save 83% of energy used in the traditional furnace and to reduce 87.36% of the relative carbon dioxide emission. The simulation of the mathematical model made it possible to compare the numerical results with the experimental measurements obtained by the prototype as well as to validate the model and to adjust the heat transfer parameters.

Experimental Study and Energy Optimization of a Prototype Furnace for the Pottery-Ceramic Industry

In the current context of global warming linked to a significant consumption of energy and the emission of considerable amounts of greenhouse gases, it is imperative to optimize the thermal operation of industrial furnaces to reduce consumption and protect our environment. The article focuses on the heat treatment of pottery-ceramic products in a prototype furnace to improve energy efficiency. And thus, the fuel consumption and the corresponding carbon dioxide emissions. In order to make a judicious choice of the best indicator that characterizes the energy efficiency (efficiency and power) and after simplifying the firing process we precede to a parametric identification; this was being done from the measurements made on the process. We propose a prototype gas furnace and we are doing a comparative study of randomly charging and with supports for the firing of ceramic products whose objective is the determination of the optimal operating conditions with respect to an energy criterion taking into account the quality of the product. In this work an experimental analysis with a specific energy consumption (SEC) of 1.15-1.38 kJ/kg prototype furnace is presented and compared to the experimental tests carried out at the traditional furnace of 6.75 kJ/kg used in the pottery-ceramic industry in Morocco. The results of this study show that for firing using supports canals leads to a product of good quality and with reduced consumption between four to six times less of that used by the traditional furnace. On the other hand, the finding of the study show that the prototype furnace emits 402.48 kgCO2eq less compared to traditional furnace (5875kgCO2eq) which allow us to reduce the harmful emissions.

Pulling thin single crystal silicon wafers from a melt: The new leading-edge solar substrate

The Floating Silicon Method (FSM) has been established as a viable, stable method for growing single crystal ribbons directly from a silicon melt. With intense helium jet cooling to drive the linear progress of a [111] facet, pulled in the 〈110〉 direction, ribbons in the 0.6 – 3.0 mm thickness range can be grown at linear growth rates from 0.3 mm/s to >6 mm/s as reported in the literature. We report on recent progress towards growing (100) oriented ribbons with a net thickness of <200 µm and a ribbon width up to 18 cm using a stable, continuous process in the Leading Edge prototype furnace. The 3D details of the single crystal growth are explained using the mechanics of the Limit Cycle Theory, with novel Internal Side Effect morphology described by a proposed Facet Flow Theory. Grown-in crystalline defect distributions are described as well as values of critical impurities like oxygen, carbon, dopants, and metals that are relevant for use as wafers for solar cells.

Thermal Unit with Controlled Distribution of Flow Speeds of Processed Raw Materials in Zones of Electrified Modules

The article reviews the possibility of thermal treatment of vermiculite concentrates in thermal units of the modular-launch type after the defects of the units appeared during operation were fixed. It was observed that the temperatures of the electric heaters and the refractory surface of the firing modules distribute unevenly horizontally: the temperatures decreased significantly from center to periphery. This feature showed a technical solution — the division of the total flow of the expanded vermiculite into local and controlled flows between the thermal zones of the furnace modules taking into account their temperatures. The required time for particles movement in each thermal zone was determined, as well as average local speeds of their movement in the indicated zones were by comparing the thermal capacities of local vermiculate flows. The calculations of local flow rates were carried out and the total productivity of the modernized furnace was determined. The productivity of modernized furnace is 24% higher than the prototype furnace. It is shown that with an increase in productivity but equal to electricity consumption, the specific energy consumption of firing processes decreases by the same 24%. It makes the furnace more perfect and competitive.

An innovative prototype furnace designed to produce activated carbon for removal of chromium from tannery waste

In recent years, the demand for energy is increasing due to increase in population, industrial and agricultural activities. India has most resources of renewable energy and a number of technologies have been developed to harness the energy resources. There is a huge potential to separate energy from agricultural waste using a suitable technology. The organic waste from various forms can be treated either by a biochemical or thermo chemical route. Biochemical conversion through anaerobic digestion results in the energy degradation. Thermo chemical conversion involves in the burning of waste to produce energy. The treatment method depends on factors such as quality, quantity, works and local requirement. Coconut shell and sugarcane bagasse are naturally occurring and abundant biomass which offers an economical solution for heavy metal removal. Heavy metals like nickel and chromium are main toxins which affects lives severely. The adsorption potential of activated carbon derived from a mixture of coconut shell and sugarcane bagasse has been studied for the removal of chromium from the tannery waste water collected from the Common Effluent Treatment Plant(CETP) atPallavaram, Chennai. The activated charcoal is prepared by designing a prototype furnace which accommodates large quantity of biomass and burnt in an inert atmosphere to produce activated carbon. This carbon material was collected and made into energy blocks as briquettes. These briquettes have been used as a filter bed to remove the heavy metals by developing a packed bed column experiment. Thus the experiment indicates that mixture of sugarcane bagasse and coconut shell works out as an effective adsorbent for the removal of chromium from tannery waste water.

Technological and Energy Capabilities of Electric Two-Module Pouring Furnaces with Upper Heating System

A new modified two-module electric modular-pouring furnace with an upper heating system of heaters and an additional “zero” (non-electrified) module is considered. By eliminating the lower third firing module, a reduction of energy consumption by a third compared to the three-module prototype furnace was achieved. Suspended emitting elements, which are not only energetically more efficient than the previous ones made of strip heaters, but also constructively provide double the furnace throughput due to the suspension under thermal covers, are used in the modules. This leads to a doubling of its performance. Altogether, it gives a decrease in the specific energy consumption of vermiculite firing in a new two-module furnace to a level of 50.4 J/m3.

Design of a high Temperature ‘Anaerobic Gas-Furnace’ suitable for Pyrolysis

The need for a high temperature anaerobic furnace for pyrolysis is fast becoming indispensable for technological growth in Nigeria. In this project, a high temperature furnace was designed and built using the principle of heat transfer. The furnace was made of casing of low carbon steel sheets in four rectangular shapes. The refractories made of bricks filling the cavities of the furnace. This help to preserve heat loss. The pyrolysis capsule (chamber) was made of high carbon steel tube with flanges which can be opened for loading the products and evacuate. The mechanism to regulate the temperature and the gas input were installed. The furnace was gas-fired due to its high combustibility and providing a solution to the limited supply of electricity in the country. The prototype furnace produced is easy to use and multi-versatile with the innovation of the detachable pyrolysis capsule which can be modified by intent of pyrolysis products and by-products. The pyrolysis capsule is surrounded by the flame jacket (of the furnace main chamber) created to heat up the capsule at a regulated rate to any desired temperature up to 1,200 °C with the automated control system for the gas supply unit. The designed high temperature anaerobic gas furnace is deployable for a wide range of pyrolysis processes and can be used for different precursors to produce an achievable end-product within the temperature limit.

Identification of the state-space dynamics of oil flames through computer vision and modal techniques

In industrial oil furnaces, unstable flames can lead to potentially dangerous conditions. For this reason, elaborate control systems are used to monitor the various parameters of the process that could become the source of such problems. A current trend in research is the one that seeks to apply artificial intelligence techniques to efficiently identify a priory anomalous behavior of the flames, so as to help improving the time response of the automatic control. In system dynamics theory, it is common sense that an accurate modeling of the process under study directly affects the performance of the controlling apparatus. Unfortunately, due to the complexity of the process, physical models of flame propagation are still not as much faithful as they should to be used for control purposes. On the other hand, could the complex dynamics of flame propagation be described in terms of an identified assumed model, one would come up with a tool for the improvement of the control strategy. In this work, a new approach based on Operational Modal Analysis (OMA) tools is used to identify four degree-of-freedom second order state-space models of oil flame dynamics in a prototype furnace. Grabbed images of a CCD camera, after being processed through a computer vision method, provide sets of characteristic vectors which, then, serve as input data to an identification OMA algorithm based on the Ibrahim Time Domain Method. Models of unstable and stable flames are built and validated through spectral analysis of the reconstructed time-domain characteristic vectors. The truthfulness of the validation scheme was then confirmed by a quantitative modal assurance criterion modified to suit the current application. On the grounds of the results obtained, it is possible to assert that the proposed approach for the description of flame dynamics can likely predict the occurrence of unstable conditions, thus becoming another tool that might be used in an automated control system.

Mathematical Modeling of the High Temperature Treatment of Birch in a Prototype Furnace

In recent years, various wood modification technologies have been commercialized as alternatives to the traditional chemical treatments for wood preservation. The high temperature heat treatment of wood is one of these commercially viable and environmentally friendly alternative wood modification technologies. During this treatment, wood is heated to temperatures above 200°C by contacting it with hot gas. The chemical structure of wood changes leading to increased dimensional stability and resistance to microorganisms. Wood darkens making it aesthetically more attractive. However, it loses some of its elasticity. Therefore, the high temperature heat treatment has to be optimized for each species and each technology. The mathematical modeling is an important tool for optimization. It can also be used as a powerful tool for furnace modification and design. A reliable and predictive model was developed to simulate numerically the heat treatment process. Heat treatment experiments were carried out in the prototype furnace of the University of Quebec at Chicoutimi. The model was validated by comparing the predictions with the experimental data. In this paper, the results of the model applied to birch heat treatment are presented. The model predictions are in good agreement with the data.

Effect of thermal modification on mechanical properties of Canadian white birch (Betula papyrifera)

Wood is a renewable material widely used in the construction industry. However, it is susceptible to fungal degradation. Several chemical products have been developed to improve its durability, but the toxicity of some of these products limits their use. One alternative to chemical treatment is thermal modification of wood. This method improves the dimensional stability of wood and reduces its susceptibility to decay. The impact of different parameters (maximum temperature, heating rate, holding time and gas moisture content) of thermal modification on the mechanical properties of Betula papyrifera was studied in a prototype furnace. The results show a marked decrease in the modulus of rupture with increasing temperature while the modulus of elasticity does not seem to be affected. The hardness increases with maximum modification temperature, and in the absence of moisture in gas, and there is an improvement in the dimensional stability after thermal modification.

Improvement of the heat treatment of Jack pine (Pinus banksiana) using ThermoWood technology

Thermal treatment in inert atmosphere is used to preserve wood without utilisation of toxic chemical agents. In addition, this process increases the dimensional stability of the wood matrix and results in attractive dark colour. On the other hand, it can deteriorate the mechanical strength and the flexibility of wood. For this reason, heat treatment parameters (such as maximum temperature, heating rate, the duration of the first plateau at constant temperature (100–120°C) and the second plateau at the maximum treatment temperature, humidity, final cool down rate) must be optimised in order to benefit from advantages of thermal treatment without deteriorating significantly the mechanical properties of wood. Correlation between wood properties and thermal treatment parameters depends not only on the wood species but also the environment (climate, soil) where the given species grow. This paper presents a study on thermal treatment of Canadian Jack pine (Pinus banksiana) using a medium size prototype furnace. The aim of this study was to optimize the set of parameters used during industrial treatments. The possibility of shortening the process time without causing any deterioration in wood quality was also investigated. The results show that increasing the maximum heat-treatment temperature increased the dimensional stability of Jack pine and darkened its colour. This parameter did not affect the modulus of elasticity but it decreased the modulus of rupture of Jack pine. A slight reduction in gas humidity during the initial warming up period permitted to shorten the drying period and at the same time increased the mechanical strength. This improvement helps save energy and increase productivity.

Concept of Furnace for Metal Refining by Microwave Heating &amp;mdash;A Design of Microwave Smelting Furnace with Low CO&lt;SUB&gt;2&lt;/SUB&gt; Emission&amp;mdash;

A concept of ore refining by microwave heating and a model of the microwave smelting furnace were proposed in order to build the first prototype furnace for efficient iron ore refining. The repose and wall friction angles were measured for powdery ores (mined in Robe River, Australia), and the electromagnetic field distribution was analyzed through numerical calculation to design the furnace.The hearth angle needs a certain amount of degrees, and the degrees must be less than 19.8-degrees in perspective of the mass transfer. A reverberator type furnace was adequate and utilizeed the energy efficiently. The reflected output reached the maximum when the electric wall was made at the cone surface.

Production of anhydrous borax from borax pentahydrate

Anhydrous borax is an important compound because it can be used to produce sodium borohydride which is one of the best chemicals that carry hydrogen and releases hydrogen upon hydrolysis. In this study, a prototype furnace for the production of anhydrous borax is designed and manufactured at Eti Mine Works Kırka Borax Managing Administration located at Kırka County of Eskişehir Province in Turkey. In addition, a product processing unit based on the method of powder atomization is designed and manufactured. After manufacturing works, a set of experiments is performed and anhydrous borax is produced. As a result, anhydrous borax (Na 2B 4O 7) is obtained including the following constituents as mass percentages; 68.24% B 2O 3 and 30.38% Na 2O. The difficulties in the post-processing stage are overcome by the use of powder atomization unit and in the mean time, continuity in production is also established.

ATEN: a new high temperature materials processing facility for the international space station.

Since the beginning of microgravity materials research, studies of diffusion in liquids have been performed as the typical research that efficiently uses the microgravity environment. Successful experiments in microgravity have demonstrated the ability of the Canadian Microgravity Program (QUEST I, QUELDs I and II) to make significant contributions to this field of international microgravity research. Recently, Millenium Biologix was selected to develop and build the advanced thermal environment facility (ATEN) for the International Space Station. The design of this new processing facility builds on the considerable experience gained in designing and building the QUELD II furnace and developing sealed samples for use on board a manned space platform. The system requirements for ATEN are presented, along with preliminary test data from a prototype furnace.

Evaluation of Ferroniobium Carbide Production in a Laboratory-Scale Plasmacan Furnace

AbstractThe Plasmacan furnace is a transferred arc, falling film, plasma furnace designed for the treatment of fine particles. A 60-kW research prototype of this furnace was tested for the production of ferroniobium carbide by the carbothermic reduction of pyrochlore. Only low niobium content alloys could be made because the prototype furnace was heavily-cooled and limited in arc current. The desired conversion of 30% could be obtained in the sleeve of the furnace and high conversions were achieved in batch experiments. The results showed that conversion reaches a maximum and then decreases as the specific energy consumption (SEC) is increased because the quality of the molten falling film is optimized at intermediate SECs. The results suggest that a ferroniobium of commercial specifications except for a high carbon content could be produced in a larger scale Plasmacan furnace process.

Evaluation of Ferroniobium Carbide Production in a Laboratory-Scale Plasmacan Furnace

The Plasmacan furnace is a transferred arc, falling film, plasma furnace designed for the treatment of fine particles. A 60-kW research prototype of this furnace was tested for the production of ferroniobium carbide by the carbothermic reduction of pyrochlore. Only low niobium content alloys could be made because the prototype furnace was heavily-cooled and limited in arc current. The desired conversion of 30% could be obtained in the sleeve of the furnace and high conversions were achieved in batch experiments. The results showed that conversion reaches a maximum and then decreases as the specific energy consumption (SEC) is increased because the quality of the molten falling film is optimized at intermediate SECs. The results suggest that a ferroniobium of commercial specifications except for a high carbon content could be produced in a larger scale Plasmacan furnace process.

Melting and casting of alloys in a solar furnace

A feasibility study conducted using a small working model of a solar furnace is reported in which the melting and casting of various alloys was tested. The prototype furnace had either a spun copper or aluminum hemispherical concentrator, and was manually tracked. A later self-tracking version consisted of a paraboloidal cofiguration fabricated from a wire mesh antenna covered with aluminized polyester. The experimental results show that a simple and inexpensive solar furnace could be commercialized in the near future. (SPH)

Heat treatment in a fluidized bed furnace

1. The controlled atmospheres obtained during the combustion of natural gas in the prototype furnace with fluidized bed at α≤0.45 sharply reduce oxidation and decarburization during the heating of alloy steels to 900–1000°C. In a carefully controlled furnace no decarburization of the surface layer takes place. 2. The heating of steels takes place in a fluidized bed at a considerably higher rate than in an electric furnace so that the heating time for hardening decreases in a ratio of 12∶1 and for tempering in the ratios 8∶1. 3. The hardening ability of a fluidized bed is the same as that of oil. 4. Mechanical properties and hardness of 18Kh2N4VA and 40KhNVA steels heat treated in a fluidized bed are stable and meet the specified requirements. 5. High-speed heat treatment in a fluidized bed without oxidation or decarburization of parts is recommended for use in industry.