GB2131140A

GB2131140A - Heating method and apparatus

Info

Publication number: GB2131140A
Application number: GB08331241A
Authority: GB
Inventors: Fanti Giovanni De
Original assignee: Individual
Current assignee: Individual
Priority date: 1982-11-26
Filing date: 1983-11-23
Publication date: 1984-06-13
Also published as: IT8224458A1; FR2536834A1; DE3342042A1; IT1154590B; GB8331241D0; IT8224458A0

Abstract

In a method of heating buildings utilising waste material a fuel, the waste is dried in a dryer 3 and then transferred to a silo 5. As required dried waste is withdrawn from the silo and crushed in a cutter 6 and drawn by suction to a cyclone 8. Separated waste from the cyclone and air pass to the combustion chamber of a bailer 10. Air from the upper part of the cyclone 8 is passed to the interior of the boiler 10 to produce a better circulation of fumes and improve combustion. Water from the boiler is used to heat the drier 3. <IMAGE>

Description

SPECIFICATION Heating method and apparatus The present invention relates to a heating method and apparatus. More particularly, the present invention relates to a method and apparatus which are particularly suitable for heating industrial premises since the fuel which is employed is waste or refuse material generated by the industrial premises such as, for example, wood dust, footwear dust or poultry excrement.

It is well known to heat industrial premises by means of a coal, gas or oil-fired boiler plant. However, as the worldwide stocks of these fossil fuels dwindel, such conventional heating plants become more and more expensive to operate.

As a consequence of this, it is becoming more and more expensive to maintain adequate working temperatures in such industrial premises. Moreover, such premises are usually badly thermally insulated for the obvious reason of economy in the construction of the premises.

Furthermore, such premises generally have a high ceiling or roof which means that the volume to be heated is large. The heating costs are therefore considerable and much of the heat is utilised to raise the temperature in the air space above the workforce. This problem is particularly important in animal farms where the temperature cannot be allowed tofall below a predetermined limit.

The present invention therefore seeks to provide a heating method and apparatus which will overcome at least some of the above-mentioned disadvantages by utilising refuse material produced by the premises as the fuel. For instance, wood industries can use wood chips or wood dust, shoe factories can use shoe dust, and the animal farms can use animal excrement, which term includes material removed from the cages during the cleaning thereof and which may include wood chips, wood dust and other materials used to make beds for the animals as well as the excrement of the animals.

According to the present invention, there is provided a method of heating buildings, utilising waste material as fuel comprising the steps of feeding and drying the waste material to be used as the fuel, crushing the dried waste material, blending the fuel material thus obtained with a quantity of air necessary for burning the material and simultaneously admitting air into a combustion chamber to promote better fume circulation.

Also according to the present invention, there is provided an apparatus for carrying out such a method comprising means for drying the waste material intended to be used as the fuel, means for crumbling or crushing the dried material thus obtained and means for mixing the crushed, dried fuel with a quantity of air necessary for subsequent combustion and combustion means for burning the fuel.

The invention will be further described, by way of example, with reference to the accompanying drawings, in which: Figure 1 shows a schematic side elevation of a heating apparatus according to the present invention; Figure 2 shows a top plan view of a modifi- cation of the apparatus shown in Fig. 1, and Figure 3 shows a sectional view taken through a drier forming part of the apparatus shown in Figs. 1 and 2.

With reference to Fig. 1, an apparatus according to the present invention comprises an elevator 1 which draws the material to be used as the fuel from a source 2 thereof and transfers it continuously to a drier 3 to be described in greater detail hereinafter.

An exhaust conveyor 4 is provided at the outlet of the drier which transfers the material to a silo 5. At the base of the silo 5 is a withdrawal cutter 6 which sends the material, by means of a second exhaust conveyor 7, to a cyclone 8. The cyclone 8 has two outlet ducts. The first outlet duct 9 permits the passage of the fuel into a boiler 10 having a burner 11 whilst the second duct 1 2 connects the upper part of the cyclone 8 to the lower zone of a combustion chamber.

The fumes, which are emitted by the boiler 10, pass through a second cyclone 1 3 from which they are removed by means of an exhauster 1 4 which allows them to be conveyed to a chimney.

The boiler 10 is also connected, by means of a duct (not shown) to the drier 3, which duct carries hot water necessary to keep constant the internal temperature of the drier 3 for treating the excrement.

The drier 3 provides for the continuous passage of material and consists of three concentric chambers, best seen in Fig. 3. The outermost chamber 1 6 is filled with insulating material in order to prevent heat losses in a radially outward direction. The middle chamber 1 7 allows the hot water issuing from the boiler 10 to circulate therethrough, whereas the inner chamber 1 8 contains the fuel material, such as the excrement, to be dried.

The axis of the drier is inclined so as to favour the continuous flow of the excrement towards the outlet of the drier. The excrement is mixed by means of an agitator having radial paddles 1 9. The inclination of the drier and the rotational speed of the agitator 1 9 are obviously selected in dependence upon the length of time the excrement needs to remain in the drier. Experiments have shown that the excrement dries in a time less than 13 minutes if the water circulating in the chamber 1 7 is at a temperature of 80 to 90"C. The various components of the plant can, if desired, be arranged more compactly, as is illustrated in Fig. 2, if necessary or desired.

The operation of the above-described apparatus will now be described. Moist, and therefor unutilizable, material such as excrement is drawn from the source 2 by the elevator 1 which provides a continuous flow of material into the drier 3. A flow of water from the boiler 10 maintains the temperature inside the drier constant. In the drier 3, the excrement is continuously mixed by means of the paddles of the agitator 19. Since the drier is inclined, the drying excrement descends slowly towards the lower part of the drier, the rate at which it does so being a function of the angle of inclination of the base of the drier and the rate of rotation of the agitator.

Once this phase has finished, the excrement has been substantially completely dried and is ready to be burnt. It is therefore extracted by the exhauster 4 and is accumulated in the silo 5. When necessary, the cutter 6 draws out the compacted excrement from the bottom of the silo 5 and triturates it until it is reduced to a grain size suitable for good combustion.

The material thus obtained is removed by suction by an exhauster and is caused to enter the cyclone 8. This cyclone separates and removes surplus air used for drawing in the grains of excrement so as to allow the passage into the combustion chamber of the boiler 10 of an appropriately dosed blend of air and combustible grains.

The surplus air, which is removed from the upper part of the cyclone 8, is returned to the interior of the boiler 10 and is used to produce a better circulation of the fumes and a more perfect combustion. The fumes are subsequently purified inside the cyclone 13, from which the exhauster 1 4 causes them to enter the discharge chimney 1 5.

it is also clear from the above description that the process according to the present invention comprises the foliowing phases: A) A first phase of feeding and drying the excrement with the possibility of the subsequent accumulation thereof in a storage zone; B) The fedding as and when necessary, of the dried material crushed to grains of suitable dimensions; C) The blending of the intended fuel material thus obtained with a quantity of air required for the combustion thereof and the simultaneous admision of air into the combustion chamber to promote a better circulation of fumes; D) The collection and purification of the fumes; and E) The utilization of a part of the heat thus obtained to heat water which is used to maintain a constant temperature inside the drier 3.

It is clear, therefore, that the above-described method permits reruse material to be treated so that it may be used for heating buildings. It is possible to have a completely self-contained plant which provides its own heating fuel without the need for resorting to other expensive kinds of fuel.

The plant may be obviously dimensioned in dependence upon the type of the refuse material available and which is to be used as the fuel. Similarly, the temperature inside the drier 3 and the dwell time of the material therein are selected in dependence upon the characteristics of the material itself.

Claims

1. A method of heating buildings, utilising waste material as fuel comprising the steps of feeding and drying the waste material to be used as the fuel, crushing the dried waste material, blending the fuel material thus obtained with a quantity of air necessary for burning the material and simultaneously admitting air into a combustion chamber to promote better fume circulation.

2. A method of heating buildings as claimed in claim 1, wherein the drying of this material is effected utilising part of the heat produced during the combustion.

3. A method of heating buildings as claimed in claim 1 substantially as hereinbefore described.

4. An apparatus for carrying out the method as claimed in any one of claims 1 to 3 comprising means for drying the waste material intended to be used as the fuel, means for crumbling or crushing the dried material thus obtained and means for mixing the crushed, dried fuel with a quantity of air necessary for subsequent combustion and combustion means for burning the fuel.

5. An apparatus as claimed in claim 4, wherein the drying means comprises a drier capable of providing a continuous supply of dried material to be burnt, the drier having an opening or channel formed therein to permit the circulation of hot water used for heating the building therethrough so as to maintain a desired temperature within the drier.

6. An apparatus as claimed in claim 4 or 5 comprising means for crushing and crumbling the material to be burnt and blending it with an adequate quantity of air, means also being provided for supplying an air blast to the interior of the combustion means to promote better circulation of the fumes.

7. An apparatus as claimed in claim 6, wherein a cutter is provided for crushing the material to be burnt, which material is drawn from an accumulation zone, an exhausterconveyor for allowing the passage of the material to the combustion chamber, a cyclone being provided between the exhauster and the combustion chamber for seperating the surplus air from the fuel-air mixture and for directing such surplus air towards the lower part of the combustion chamber.

8. An apparatus as claimed in claim 7, wherein a second cyclone is provided at the outlet of the combustion chamber for purify ing the discharge fumes.

9. A heating apparatus as claimed in claim 4 constructed and arranged to operate substantially as hereinbefore described with reference to and as illustrated in Figs. 1 and.3 or Figs. 2 and 3 of the accompanying drawings.