Apparatus and method for fractionating alternative solid fuels

Abstract

An apparatus and a method for fractionating alternative solid fuels, specially whole tires, into volatiles and coal, to be used as alternative fuels, and metal, the apparatus comprising: a feeding zone wherein the solid fuels are feed to the apparatus, a gasifying zone into which the solid fuels are processed, obtaining a gaseous fraction, coal and metal; cooled grills controlling the bed permeability and permanence time of the solid fuels at the gasifying zone; and a discharging zone into which the resultant coal and metal are discharged.

Description

BACKGROUND OF THE INVENTION[0001] 1. Field of the Invention[0002] This invention relates to an apparatus and a method for the recovery of energy from solid waste, by combustion of the solid waste in industrial kilns and more particularly to an apparatus and a method for fractionating alternative solid fuels, such as tires, into volatile gases and coal to be used as alternative fuels, and metal.[0003] 2. Description of the Related Art[0004] Since 1980, hazardous solid waste, such as discarded tires from all kind of vehicles, has been used as an alternative or supplemental fuel in kilns for the production of cement.[0005] The necessity to reduce total fuel costs through the substitution of waste-derived fuels instead the normal fossil fuels, primarily coal, has been the main driving force behind the desirability of cheap alternative fuels to fire industrial kilns such as kilns for producing cement.[0006] One of the most readily useable and highest heat content non-hazardous wastes, co...

AI Technical Summary

Benefits of technology

0030] It is also a main objective of the present invention to provide an apparatus and method for fractionating alternative solid fuels, of the above dis

Problems solved by technology

There are however some disadvantages in the use of crumb tires in the kilns for producing cement:: 1) the removal of the steel is from the crumb tires is very difficult, notwithstanding that cement has a need for iron in its process; and 2) the production} of the crumb is quite expensive, making the crumb as costly as the coal or coke.

There are, however, some disadvantages in the use of tire chips: 1) similarly to the tire "crumb", the production of chips from whole tires is also expensive, certainly not as costly as the production of crumb, but often represent a half the cost of acquiring and delivering the supplemental fuel; 2) the steel wire from the bead and radial belts of the tires do not shear smoothly when the tires are chipped and consequently, the chips are ragged and the steel wires protruding the chips, hook everything they come into contact with, making difficult the operation of the plant.

However, despite the above advantages the use of hole tires present some problems related to the removal of steel wire from the gasifier section of the kiln, which tends to get entangled into of the gasifier forming a great tangle of wire, affecting the flow of volatiles from the combustion chamber to the kiln or calciner, decreasing the fuel substitution percentage and limiting the use of whole tires as supplemental fuel.

Ogawa's method has the limitation that it is only able to use grounded tires since it does not have any means to prevent entanglements of wire or means to remove the wire which is released when using whole tires.

Furthermore, Ogawa's method does not show any means to control the bed permeability and permanence of the grounded tire at the calcination point which would be highly desirable since, by controlling the permanence time and permeability of the bed will allow a complete calcination of the tire and an adequate production and flow of the volatiles to the point of combustion.

Although in Steinbiss patent it is possible to control the permanence time of the waste materials in the furnace, this method and apparatus is not intended for whole tires and it is a fluidized bed gasifier.

Therefore it can not gasify whole tires and discharge the wire.

Furthermore, since the main objective of this invention is the disposition of hazardous and waste materials, it is designed to use only waste materials of low heat content, therefore the quality and quantity of volatile produced is very low and can not be considered as a suitable supplemental fuel for industrial kilns.

The main disadvantage of this method is that the heat released by the combustion of volatiles would overheat the back end of the kiln and would induce the formation of very hard agglomerates which are very difficult to remove.

Although Rechmeir process discloses the separation of the residual carbon form tires, it does not disclose the separation of the wire or the management of the wire into the pyrolyzer, which would limit the use of whole tires.

In Tutt's apparatus, the tires are directly feed into the kiln, and therefore the disadvantages are similar to those of Tsuda's method.

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