COKELESS CUPOLA FURNACE PDF

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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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However, this has a slight negative impact on carburization.

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However there is still dirt in the charge and sand sticking to the returns, and so these materials still have to be converted into a fluid slag. 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.

With a long-term hot-blast cupola furnace with lining brick-lined furnace shellheat losses can be reduced to a minimum. Some examples will now be described to illustrate what can happen when a cokeless cupola is not run in accordance with the invention. We have to import coke from other countries. Moreover, in a cokeless cupola slag control is much more critical because of the lower temperatures.

US5294243A – Method of operating cokeless cupola – Google Patents

The SPM level, as measured in actual installations, is less than one third the allowable limits. In order to guarantee uniform melting conditions, the furnace is equipped with state-of-the-art gas burners. Generally limestone or dollastone is used as the fluxing material, or sometimes a mixture of the two.

It is sometimes necessary to add further materials such as a fluorspar which makes the slag more reactive to the ash so that both better carbon pick-up and better temperatures in the furnace can be obtained. The energy consumption can fufnace reduced by introducing secondary air above the melting zone and injecting oxygen. An important feature of the cokeless cupola is that during operation there is no visible emission and the actual solids emitted are very low and are only dependant on the cleanliness of the charge.

As this is a considerable growth area in India, it offers foundries an additional advantage over competitors who are still using a conventional coke cupola.

In a cokeless cupola lined with a high alumina material, and operated for one week without repair although melting on only a single shift, the quantity of dollastone added to take care of the dirt, and the products of wear on the spheres and the wear on the lining was of the order of 2 to 2.

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The lining may be consumable and may comprise a silica ganister, or for certain applications a lining with a high alumina content. This example shows, amongst other things, the importance of the slag having sufficient volume to flow during tapping, especially during continuous tapping.

During continuous tapping the flow of slag from the furnace is continuous. Javascript is required to use GTranslate multilingual website and translation delivery network. This means higher rate of consumption of spheres. Search Expert Search Quick Search. 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. 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.

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. Other advantages of cokeless melting include cleaner and better quality metal, there is also less refractory lining wear and hence longer campaigns are possible.

Moreover, in a cokeless cupola slag control is much more critical because of the lower temperatures. United States Patent Because of the semi-permanent nature of the bed and the ability to control carbon content by injection as well as the precise control of the combustion process, both iron temperature and iron analysis are far more consistent than that from a coke cupola.

Instead it tends to be held above them and it then builds up in a layer above the spheres.

Depending on the fuel used and the recarburiser injected there is no sulphur pick-up in melting. A special compensating siphon is used to adjust the slag bath height according to the desired carburizationmaking it possible to change the dripping zone in the cupola seen from the siphon.

Pig iron Foundry pig iron Furnace clogging Literature: This cupola is operating on natural gas and using graphite for injection. Method for reducing iron oxides and for melting iron and installations therefor. At present in the rare occasions that the operator of a cokeless cupola considers how much fluxing agent to add his instinct from working with coke cupolas where the precise amount of fluxing agent does not matter – so long as there is enough is to shovel on a lot of fluxing agent, and then shovel on another few shovelfulls for luck.

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This influences the melting rate, which also effects the gas consumption. Although the price of coke, fuel and electric rates may vary from location to location, it is clear that the cokeless system can offer considerable economic benefits, with duplexing operation offering the highest saving. Also, considering the shortage of power in India, it may be noted that when duplexed with Induction Furnace for production of Ductile Iron, the power requirement is reduced substantially.

The melting zone is closer to the nozzles than in cold-blast cupolas. This normally results in excessive consumption of the heat-exchange bodies. This means a considerable improvement over cold-blast operation.

Method of operating cokeless cupola – Cokeless Cupolas Limited

It is not possible to achieve zero sphere consumption, but we have discovered that there curnace an optimum consumption for different modes of operation. A typical slag analysis would have a composition in the following range: Pig iron is the most expensive raw material in a cupola charge whereas steel scrap is cheaper.

There will still be some dust emissions from the charge but these can be readily removed if required. Each burner has its own gas, air and oxygen valves for precise regulation of burner performance.

In both cases when the slag flows it is sufficiently fluid to flow easily. Thus, it is possible to express a defined combustion ratio eq. 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. A 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 metal temperature.

In a unit melter fairly high tapping temperatures will be required. To achieve tapping temperatures of around to deg C a bed height of around mm would be required. In addition to the savings below, there are substantial savings for an EcoMelt Cokeless Melting Furnace compared to a coke cupola as there is almost no need for pollution control equipment.