Autotherm Equipments Corporation is well known manufacturer,exporter and supplier of Cokeless Cupola Furnaces at market leading price from Coimbatore,, . EcoMelt Cokeless Melting Furnace is a Vertical Shaft Melting furnace and was as a melting unit for Cast iron without use of coke as in a conventional cupola. The development of the cokeless cupola began in the United Kingdom at the foundry of Hayes Shell Cast Limited in the mid s. A pilot furnace was built.
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The whole question of fluxing agents is not so well understood, nor its importance appreciated, in cokeless cupolas. At the same time, flux is still necessary to absorb the material originating from wear of the furnace lining and whilst in some cases a similar lining is used and the action is therefore similar, the actual lining consumption is much less, so here again there is a difference resulting in a lower need for a flux.
A method according to claim 16 wherein the silica comprises broken bottles, jars, gravel. The oxidation losses are lower than in a coke-fired furnaces so again, from this aspect, less flux is required. The energy consumption can be reduced by introducing secondary air above the melting zone and injecting oxygen. Advantages of the liningless furnace include a reduced lining effort and the somewhat longer furnace campaign, while long-term furnaces with a lining provide the benefit of lower heat losses, ultimately resulting in reduced coke consumption and better energy utilization associated with the above-mentioned benefits for the environment and the climate.
However, with the injection process used in the Cokeless Melting Furnace, this does not present a problem.
The lower slag volume that results in the operation of the cokeless cupola is not a problem in intermittent tapping and is certainly an advantage for slag disposal. EXAMPLE II Cupolq cokeless cupola operating with a clean charge and with what were mistakenly thought to be correct proportions in the charge including 12 Kg of dollastone per charge was found to exhibit very rapid consumption of the spheres, with the consequence that the bed almost vanished by the end of an eight-hour shift, resulting in insufficient superheating and low furnxce temperature.
The carbon content of the metal can be easily altered by changing the injection rate at the control panel. If insufficient fluxing agents are added, the result is a slag which is viscous rather than fluid, and it does not flow easily through the spheres. The melting point furace the slag was barely higher than the tapping temperature and so with a small stream of slag the stream cokelfss freeze off altogether and had to be re-started.
This makes durnace easier and more economic. This control may involve deliberately increasing the volume of slag by suitable additions in order to operate a continuously tapped furnace smoothly. Even where the metallic charge is known to be of pure metal free from dirt and sand, it is still essential to add fluxing agents to form a slag, if only to absorb the products of lining wear and sphere consumption.
The lower slag volume that results in the operation of the cokeless cupola is not a problem in intermittent tapping and is certainly an advantage for slag disposal. Broadly speaking, therefore, the invention is based on an appreciation of the importance of slag control in the operation of a cokeless cupola furnace with the minimum of trouble, in particular without problems originating from a slag which is too viscous, yet at minimum cost, that is to say, low sphere consumption and low lining wear.
The cold-blast cupola furnace has a high specific coke consumption since a large part of the energy is discharged together with the exhaust gas in the form of carbon monoxide. However, we have appreciated that the types of flux materials generally employed in order to produce a fluid slag also attack the spheres, and that it is very important to control the addition of fluxing agents.
Reduced bed height reduces the tapping temperature but increases the melting rate. Difficulties arose through bridging of the metal, and the slag was very sticky.
It was found that the slag did not flow continuously and the operators had great difficulty in repeatedly opening rurnace box to remove the slag. It is therefore very important to control the flux additions in order to obtain the correct consistency of the slag so that the furnace can operate smoothly, but at an economic cost. We have discovered that slag control is essential to the correct operation of a cokeless cupola as opposed to being of minor importance as was previously felt.
Similar percentage of sponge iron may also be used in Cokeless Melting Furnace, provided suitable arrangements to charge the same are made. The conventional operation of a cokeless cupola furnace has a requirement for a low volume of slag to be produced, because of the fact that there is no ash from coke to remove from the charge, and the fact that flux added to the charge to form slag eats away at the furnace lining, and at the bed of refractory spheres.
A method according to claim 6 wherein the silica comprises broken bottles, jars, gravel. The primary function of the slag is therefore to absorb the ash in the coke and other impurities in the charge. A method according to claim 16 wherein the silica comprises broken bottles, jars, gravel. A method according to claim 1 which further comprises the step of re-cycling slag removed from the furnace by re-introducing at least a portion of the slag as a component of the slag-forming fluxing agents.
This avoids handling difficulties. A method according to claim 2 wherein limestone, dollastone is added to the re-cycled slag as another component of the fluxing agents. It follows that less slag is made and hence there are less disposal problems.
US5294243A – Method of operating cokeless cupola – Google Patents
The principle of the design is highlighted in the diagramatic drawing below. India does not have reserve of good quality coking coal. The melting zone is closer to the nozzles than in cold-blast cupolas.
A pilot furnace was built during to prove the ideas of melting cast iron with gas at a relatively low temperature and then superheating by some other means. An automatic control system forms part of the main control panel and the air and fuel flows to each burner are also monitored. Cold-blast operation is known to have difficulties reaching high spout iron temperatures, unless coke charge and blast volume are increased to the detriment of the melting rate see Cupola furnace network diagram.
Moreover, in a cokeless cupola slag control is much more critical because of the ckkeless temperatures. The most important aspect which highlights the invention is the use of refractory spheres in the cokeless cupola, furnaxe described in our British Patent Specification No.
In this case high-alumina linings are often employed and this alumina has to be absorbed into cupo,a slag as the lining wears.
Longer melt campaigns of up to 48 hours are possible with minor modifications in refractory specification and water spray cooling of the shell near the burner area. Accordingly, the exhaust gas contains high concentrations of carbon monoxide. This slag volume would then in many circumstances be similar to that in a conventional coke cupola. Process of blowing high-oxygen gases into a molten bath which contains non-ferrous metals.
This example shows, amongst other things, the importance of the slag having sufficient volume to flow during tapping, especially during continuous tapping. Both Cokeless Melting Furnace and the Induction furnace may be run by a standby generator of reasonably low rating. If more limestone were to be added in a cokeless cupola to maintain fluidity it would increase greatly the rate of consumption of the spheres, increasing the overall running costs as well as shortening the length of melting run that is possible.
Cold-blast cupola furnace In cold-blast cupolas, cold combustion air is supplied to the furnace as the exhaust gas is not thermally recovered extraction above throatthis usually refers to small-sized furnaces melting rate of approx.
As a result, for same quantity of molten metal, much less CO 2 is emitted. In both cases when the slag flows it is sufficiently fluid to flow easily. The melting point of the slag was barely higher than the tapping temperature and so with a small stream of slag the stream tended freeze off altogether and had to be re-started. The charge material melts, is superheated while it is in contact with the ceramic bedding and drips into the hearth.