DE2658778A1 - METHOD AND DEVICE FOR THE PRODUCTION OF A FUEL - Google Patents

Description

DK in «DirL-ΙΚΐα M. SC. OI ^ L.-PHV ». DR OI ^ L.-PHY ". HÖGER - LEGAL RIGHTS - GRIESSBACH - HAECKER PATENT LAWYERS IN STUTTGART

26 ^ 8778

A 42 154 b

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December 22, 1976

Refuse Derived Fuels (London) Limited

London N 17 ODH Great Britain

Method and device for producing a fuel

The invention relates to a method and a device for producing a fuel. Furthermore, the registration concerns a process for generating heat using this fuel.

The elimination or further processing, generally the treatment, of waste containing solid organic material,

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for example, garbage can, kitchen garbage, garbage or The like, of which in the following for the sake of simplicity the term "solid organic waste" is used, provide in Regarding the question of how to finally destroy this waste, pose a significant problem.

There are generally three widely used methods of disposing of such organic waste, namely:

(1) dumping or sanitary landfilling;

(2) the incineration or

(3) composting.

The first method, the unloading, is in the past has been practiced to a large extent and still is, but it is becoming less and less popular because of the suitable places for Unloading is becoming increasingly rare and since the environmental pollution of this method is becoming more and more apparent. At the The usual incineration of organic waste requires relatively expensive incineration devices, since the water content of solid, organic waste can be up to 50 wt .-% and because for this reason additional fuels are required for the combustion, which increases the cost and labor of the procedure can be increased. Finally, the relatively high amount of ash produced by the material is a problem, as this ash needs to be eliminated. The composting of organic waste offers from an ecological point of view and in terms of the Environmental friendliness is an acceptable solution as you get that

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ORHMNAL INSPECTED

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the resulting product can be used for soil improvement (fertilization). If the demand for this material for this Purpose is not big enough, then the material is still less unsightly and in terms of environmental pollution less problematic so that it can be dumped rather than the original, untreated waste material. Nevertheless Composting has not experienced great success so far, as the agricultural industry has so far been reluctant to use it the end product was convincing (probably because of the trace elements or the inert material, e.g. glass, which is contained in the compost). In addition, there are the great costs involved in setting up suitable composting plants arise, obstructive. As a result, garbage dumping is one of the three major disposal types still the most widespread, which is due both to the generally lower cost and to it is that rubbish dumping has been in place for many years now.

The present invention is based on the object of a method for treating solid, organic waste material to propose with which a fuel can be produced.

This object is achieved according to the invention in that solid organic waste is composted to produce a compost product with a water content of less than 20% by weight obtain.

It is also an object of the invention to provide a device for implementation to create this procedure.

ORISINAL! NSPEGTED

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According to the invention, this object is achieved by a device with a rotatable device that receives the solid organic waste Drum, the inside mixing elements for ventilation and / or by mixing the waste in the drum and a drive for rotating the drum, which is characterized in that at least some of the Mixing elements are designed as hanging chains.

With the proposed method and with the proposed device, a solid, organic waste material can be Fuel can be produced which is a composted product with a water content of less than 20% by weight and a calorific value based on the dry matter of at least 3000 calories per gram.

According to the invention you can burn this fuel Generate heat.

The present invention is therefore based on the knowledge that the composting process can be carried out in such a way that a Product with a relatively low water content is created (i.e. with a water content of less than 20% by weight) and that this product has a sufficient calorific value (e.g. in the order of between 3000 and 5000 calories per Grams of dry matter), making this material suitable as a fuel. Water content and calorific value of the product are therefore such that not only self-sustaining combustion is possible, but that when the Product usable thermal energy is generated.

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An essential step of the proposed method comprises the composting of an organic waste material in order to produce a to produce a relatively dry product. The term "composting" as used in the present application is intended to describe an aerobic fermentation or fermentation process of the organic material. During this fermentation process carbon dioxide is evolved and the temperature of the fermenting material rises. This rise in temperature drives water vapor from the fermenting material so that it is dried out or dehydrated. There are already a number of procedures and devices have been proposed by which fermentation or composting of organic material is carried out can be. Essentially, all of these processes also include the steps indicated above, namely fermentation or fermentation of the organic waste under aerobic conditions. However, the methods described so far are in has essentially been carried out in such a way that a product with a relatively high moisture content is obtained (e.g. 40% by weight Water or more). To achieve this, special measures were taken, namely by adding the organic Waste or fermenting material has added enough water to keep its moisture content at a desired, to maintain a relatively high level. On the other hand, according to the present invention, the moisture content and the others Process conditions so that the end product has a relatively low moisture content. In addition, the Fermentation process according to the invention are carried out so that there is less fermentation of the material, so that a Waste of the combustible material is reduced. In the past there are conventional composting processes

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was carried out in such a way that a product with a carbon-to-nitrogen ratio (i.e., C; N ratio) resulted that was as low as possible, for example 10s1 compared to an initial mixture of about 35s1 can only be carried out until a Cs N ratio of about 20s 1 to 25-1 "" is reached * In many cases, the previously known fermentation process or "the apparatus for carrying it out to produce a relatively dry product " can be used, as in the process according to the invention required, can be modified by simple changes , for example by adjusting the water content of the starting material or by varying the amount of water added during the course of the process or by changing other process conditions such as the air flow rate over or through the fermenting material present invention preferred fermentation process is in a rotary drum carried out, in particular in a drum into which the organic waste material is filled on one side of the slowly rotating drum and slowly transported through, whereby it is subjected to fermentation or disintegration, and the end product on the other side of the rotating drum exit. To support the aerobic fermentation, air is usually passed through the drum, which can also be preheated to help remove the water vapor.

As with the conventional process of composting rubbish and other waste, the waste is first pre-treated to produce large, to remove essentially incombustible objects. this

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can be done for example by sorting out by hand. Afterward metallic objects are removed from the waste material, for example with the aid of a magnetic separator. According to the present invention, the waste material is preferably pulverized before the actual fermentation process, and after the magnetic separation or preferably before. It is also convenient to take the powdered waste sift before putting it into the fermentation drum (for example, to remove material that is 5 or more centimeters). This sieving can take place before or after the magnetic separation. That held back during sieving Material, which is larger pieces of combustible material may include, such as paper or cardboard, does not necessarily have to be thrown away, but it will preferably first through a shredder or similar shredding device sent, which reduces the particle size. The material will then be used in a later Process status mixed with the composted waste. Whom" If the sieving is carried out before the magnetic separation, it can be advantageous to reduce the retained material a subject to magnetic separation *

The screened waste material is then introduced into the fermentation device, which is simply hereinafter referred to for the sake of simplicity referred to as the "drum" in which fermentation takes place. The moisture content of the screened waste will be usually in the order of magnitude between 25 and 50, more often between 30 and 40% by weight. While this moisture content is generally sufficient for the composting process water is preferably added to the waste,

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as it is assumed that this will wet the drier areas of the waste, causing mechanical degradation of the waste in the drum is supported. The starting material introduced into the fermentation drone should therefore be one Water content between 25 and 50, preferably between 30 and 45% by weight. The waste can be removed simply by adding Water can be moistened, or by adding sewage or sewage sludge, the addition of which also has the advantage brings about that further organic material is added to the fermentation material. According to the invention, the waste preferably moistened by adding sewage or sewage sludge, in particular by means of a partially dewatered sewage sludge which, for example, has a water content between 60 and 85% by weight, The use of sewage sludge for Humidification of the organic waste material not only increases the organic matter content of the fermentation material, but also serves as a useful method for dewatering sewage sludge, the removal of sewage sludge namely represents a significant problem «Mechanical methods for dewatering sewage sludge (e.g. filter presses) can reduce its water content to about 75% by weight without too much difficulty, but it is very difficult to To push the water content below this level by mechanical means. By using the sewage sludge as a dampening solution for using the waste, the sludge becomes during the fermentation process due to the heat developed during fermentation dewatered, so that the end product, which contains solid sewage sludge, has a significant impact on the initial sewage sludge has reduced water content. The weight ratio of sewage sludge and organic waste material which is in the

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22nd December 1976

Fermentation drum is introduced, of course, depends on the water content of the two materials and the desired water content of their mixture. In practice it has been found that a weight ratio between sewage sludge and organic waste material between 1: 4 and 1:12, in particular between 1: 5 and 1:10 is favorable if you use a sewage sludge with a water content of 80%. The relationship between sewage sludge and waste material is generally comparably larger for dry sewage sludge and smaller for wet sewage sludge.

The sewage sludge can be digested or raw, undigerated Sludge. As the calorific value of solids contained in undigerated sludge in general Much higher than that in digested sludge, it is often useful to mix undigered sludge in with the solid To use waste material, as in this way one obtains an end product with a higher calorific value, but with all of it other properties are the same.

After passing through the fermentation drum, the product can be subjected to a second sieving, for example on one another magnetic separator and / or in an air classifier. Then it is stored before a suitable one Combustion device is supplied. Because of the low water content, the fermented material no longer ferments and can therefore be stored without a loss of calorific value and without unpleasant odors.

It has been found that during the drying of the composted material originally in the mother liquor

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ORIGSNAL INSPECTED

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contained salts (for example those contained in sewage sludge Salts) crystallize out. It is believed that these salts beneficially increase the content of flammable substances increase in the material "

Advantageous further developments of the invention are the subject matter of the subclaims and are laid down in them.

The following description of preferred embodiments of the invention is used in conjunction with the drawing of FIG further explanation «Show it.

1 is a schematic block diagram of an embodiment of the method according to the invention?

2 shows a longitudinal section through a fermentation drum for carrying out the method according to the invention?

3 is a perspective view of an end portion of the drum shown in FIG. 2 and FIG

Fig. 4 is a schematic sectional view to illustrate the feed of material into the fermentation drum and from this way.

In the method shown in the drawing, the collected garbage or garbage is placed in a garbage receptacle and tray brought, which essentially comprise one or more enclosed receptacles on a concrete floor. The collecting and the supply to the garbage bin is of course a

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intermittent process, while fermentation should preferably be carried out continuously. Therefore, the Garbage pick-up and deposit should be large enough to provide sufficient for continuous operation of the fermentation device To be able to absorb the amount of garbage and waste.

The waste to be fermented or fermented is then transported from the deposit to a first sorting zone 2, which usually has the shape of a conveyor belt. In this zone, not fermentable objects from the waste are large and removed, for example, items that are not comminuted or size reduction _vorr i _C Pla would block. These items are usually deposited according to previous practice. If desired, waste paper can be added to the waste at this stage (if there is no ready market for this paper), as this material naturally increases the calorific value of the end product (this is generally not done with conventional composting methods, as such materials have little fertilizing properties of the compost). The material is then fed from the first sorting zone to a comminuting or pulverizing device 3 in which it is comminuted, ie the particles are brought to a size between 2.5 and 5 cm. Suitable comminuting devices are, for example, vibrating hammer grinders. It is assumed that the comminution before the introduction of the material into the fermentation drum increases the effectiveness of the fermentation process in the drum, since relatively finely divided material is available for the fermentation process in this way. The crushed material is then removed from the crushing or pulverizing

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device 3 placed on a sieve device 4 (e.g. on a vibrating sieve). Oversized parts (for example, those which have a size of 5 cm and more) are from there via a magnetic separator 5 of a tearing device 6 supplied. The material passing through the screening device 4 is transported to a magnetic separator 7, in which ferromagnetic material is sorted out. The sorted ferromagnetic material can be disposed of in a landfill be deposited, but it can also be fed to a pressing device, which the ferromagnetic material to a Presses bales that can ultimately be sold as scrap. Construction and operation of the magnetic separators 5 and 7 are generally known and will therefore not be explained at this point Separator 7 introduced into the fermentation drum 8, which is divided into three areas, namely a first area 9, a Main fermentation area 10 and one. Drying area 11 (Figs. 2 and 3). Usually a moisturizing medium (hereinafter referred to as "sewage sludge") brought into contact with the waste in order to moisten it. The sewage sludge is the Waste preferably in the first area 9 of the drum 8 or immediately before the waste enters the area added to the drum 8. Introduced into the first region 9 or formed in it, an intimate mixture of Sewage sludge and screened waste. This first region of the drum preferably has protruding parts in its interior Knives or blades 17, which · serve the

Further
Sludge-waste mixture / to loosen and crush. In the first area 9 of the drum 8, so-called curtain chains 18, ie chains that have one end on the inner

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wall of the drum are attached while the other end is free, and so-called hanging chains 19, i.e. chains, both of which Ends attached to the inner wall of the drum to increase the mixing and crushing effect in this area. In the second area 10 of the drum 8, the Sludge-waste mixture subjected to the main fermentation. To ensure adequate ventilation of the fermenting mass in this area To achieve, mixing elements are preferably provided inside the drum so that the fermenting mass is rotated the drum is continuously stirred and / or sprinkled. Conventional fixed mixing elements can be used in this area in the form of knives or blades, however hanging chains 20 are preferably used as mixing elements, which are arranged along the side walls of the drum and substantially parallel to its longitudinal axis. These Chains lead to very favorable mixing and are also useful in heat transfer, so that of the fermenting mass generated heat can be used to expel the water from this mass. To get a To achieve further ventilation of the fermenting mass, air, possibly warm air, should be introduced into the drum will. This can be achieved in a favorable way that the air by means of an intake fan 12 with different Speed sucks lengthwise through the drum. If the device for the inventive implementation of Fermentation process is in the same place as the incineration plant in which the waste is incinerated, warm air can be extracted from the Incinerator used to aerate the fermenting mass; if the composted waste, for example, how to continue described below, is burned in a roasting furnace, then can

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warm (or indeed hot) air from the hot end area of the furnace or of the coolers, which the cool roasted or roasted substances.

The exhaust air of the fan 12 can be released into the atmosphere via a suitable exhaust or chimney, preferably after cleaning in a car wash. The exhaust air can also be discharged through an oven, in which the composted one Waste is incinerated, for example the exhaust air be introduced at the hot end of a rotary kiln. In this way, unwanted gases that are released during the Fermentation formed, burned

During the fermentation process develops in the drum 8, especially in the area 10 of the same, heat that served to drain the fermentation mixture To keep heat inside the drum, the drum walls can be covered with an insulating layer 21 to prevent heat losses to prevent »It is desirable that the heat generated is not lost, but rather one of the essentials Tasks of the fermentation reaction fulfilled, namely the expulsion of moisture.

The end region 11 of the drum 8 is the drying zone of the Drum. In this zone, the drum preferably has mixing elements 22, so that the mass therein undergoes constant circulation and is thus subject to constant ventilation, since it is through the drum with that of the fan 12 comes into contact with sucked air. The mixing elements in the drying area 11 preferably run for this purpose

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radially inward, more than the mixing elements in the area 10, so that in the drying area 11 a stronger Ventilation occurs. The mixing elements can furthermore be designed in such a way that they bring the composted waste mass to the outlet end the drum 8 drive. The drying area 11 can, if so desired, be different from that of the areas 9 and 10 comprehensive drum 8 separate drum be carried out.

The mixing area 9 of the drum can be replaced by its own mixer, for example by a paddle stirrer. In this case it is extremely advantageous to introduce the sewage sludge into the stirrer in order to avoid that of the magnetic Separator 7 to mix incoming, shredded waste with it. The use of a separate mixer instead the mixing area 9 makes it possible to simplify the structure of the drum and to reduce its size.

If desired, the fermentation process may be arranged 23 _e so that the temperature of the material observed in the drum and the process conditions, such as the air flow rate, the rotational speed of the drum for monitoring in each of the regions 9, 10 or 11 or at the boundaries thermocouples etc., can be set in order to obtain optimal conditions, for example to keep the temperature at the end of the fermentation zone 10 between 70 and 80 ° C, preferably between 73 and 77 ° C. In this context, it should be noted that the drum naturally rotates relatively slowly, for example at 0.5 to 4 rpm, preferably at one rpm. The drum 8 must be of sufficient length to accommodate those passing through it

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Have mass, this of course depending on the speed at which the material passes through the drum. Typically, the material runs the full length of the drum in a period of between 12 and 48 hours. In order to ensure a safe passage of the material through the drum, the latter can be inclined at a small angle to the horizontal, for example an angle between 5 and 10 , preferably of 7 °.

As already indicated, the fermentation process according to the invention so led? that the product emerging from the fermentation drum 8 is relatively dry »This is ensured by a suitable Adjustment of the water content of the sewage sludge ~ Ab £ all ~ starting mixture (The water content must of course not be too low for sufficient fermentation) and through the generation of a suitable air flow through the fermenting material or past it "achieved" is also in the drum described above a defined drying zone, the drying area 11, provided »In many conventional Fermentation drums for composting organic waste are the fermenting mass as it moves along the drum axis an additional dampening liquid (i.e. water or sewage sludge) is supplied. In the operation according to the invention such an addition is not necessary or can only be made to a very limited extent «In any case, it is extreme It is desirable not to supply any water in the end area of the drum, i.e. in the drying area. The mixing elements of this Areas are designed in such a way that they cause increased ventilation (and thus increased drying), the stronger is than in the preceding main fermentation area of the drum.

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These measures can reduce the moisture content of the composted, material exiting at the end of the drum can be reduced to the desired value.

In this context, it should be noted that the water content of the composted end product is preferably between 10 and 20% by weight, in particular between 20 and 15% by weight.

If you try to lower the moisture content below 10% by weight, it turns out that the necessary Temperature is so high that the fermentation process is seriously hampered. In addition, the calorific value of the end product no longer appropriately increased.

The dried product from the drying area 11 of the The drum is then advantageously subjected to a second readout by a second magnetic separator 13 (the Material separated in the process can either be deposited or fed to a metal press, which produces metal packages, which can be sold as scrap). The material cleaned of metal in this way is further passed into an air classifier 14 brought, the material is fed, which in the sieving device 4 has been separated and then comminuted in the shredding device 6. That from the air classifier 14 separated material (for example ashes, non-ferrous metals, glass or other non-combustible particles) is in the usually deposited in a landfill. The resulting product after the second sorting and sorting is then suitable as fuel and can be stored in a container 15 before it is burned in a furnace 16.

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Before burning, the material can be further crushed, for example in a mill. Then it can be burned in any suitable heat generating furnace. This Furnace can, for example, be a steam-generating or water-heating one Be oven. It can also be an oven used in some other industrial process, for example when roasting or burning. The product can be used as the sole fuel of the stove, but it can also used as an auxiliary fuel together with conventional gaseous, liquid or solid fuels will. In any case, this has according to the invention Process produced material has a sufficiently high calorific value to be able to give off usable heat during combustion.

The following table gives a typical mass curve for the method according to the invention, as shown in the drawing is when you treat typical household waste accordingly.

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contraption

supply

Amount of moisture from device (tons / day content) (% by weight) delivery

Amount of moisture tons / day content (wt.%)

to

to C>

to

• I * »

σ to

φ - »

N CTi- "·

CTl

Chopper 3 Sieve device 4

Magnet separator 5

Shredding device 6

Magnet separator 7

Drum 8

Magnet separator 1 3

Air classifier 14

240 240

82

80 158

158

16

120

110 80

30 30

20th

20 36

36

80

15th

16 20

Presorting shredder

Sieve device

Magn. Separator sieve device

Magn. Separator

Drained

Sewage sludge

Drum 8

Magnetic separator 13 ^k shredding device 6 240

80 2

80

155 3

120

110 10

160 25

30th

20 36

20th

20 36

15th

16 17

Sieve device

Magnet separator Magnet separator

Ripping device Metal parcel press

Air class

Drum 8 metal package press

Magnet separator 13:

Air classifier metal parcel press

Product waste

CO

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Fig. 4 of the drawing shows schematically a preferred arrangement for feeding the material into the fermentation drum 8 and for the removal of the material from the same. Shredded and sorted waste 25 is conveyed under a conveyor belt 23a Magnetic separator 7 transported to a channel 24, from where it enters the mixing area 9 of the drum 8. The drum 8 has knives, chains and mixing elements inside, as shown in FIG. 2, but these are for Promotion of clarity not shown in FIG. 4. The drum 8 is on suitable bearings (not shown) assembled; her are (not shown) drive means for rotating the drum around its longitudinal axis associated with the Rotate the drum, for example, at 1 to 4 rpm. Dewatered sewage sludge 27 is transported via a conveyor belt 26 and brought into contact with the crushed waste at the end of the conveyor belt 23a. The sewage sludge is then along with forwarded the waste into the drum 8. The inlet of the drum 8 is surrounded by a housing 28 with a line 29, wherein in the line 29 a fan 12 is arranged with an adjustable speed. The housing 28, whose The bottom formed by the channel 24 surrounds the end part of the drum 8 in such a way that the fan 12 allows air through the Drum 8 can suck. In order to reduce the entry of air into the housing 28 as much as possible, a flexible one is used Airtight flap 30 (which can be made of rubber, for example) arranged next to the upper run of the conveyor belt 23a. The conveyor belt 23a can be moved into the position marked with the reference symbol 23 · Position can be withdrawn and the inlet opening of the housing 28 can be provided with a suitable closure so that you can lock the housing when you have the

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Want to operate device with intermittent supply of waste material and / or sewage sludge.

The outlet end of the drum is again surrounded in a substantially airtight manner by a housing 31 which has an air inlet line 32 is connected. The housing 31 has a product outlet opening 33 through which the end product from the Drum portion 11 a magnetic separator 13 and a Conveyor belt 34 is fed.

The air introduced in line 32 may be hot air coming from a hot area of one of those described above Attachments can originate. The air discharged via line 29 can, for example, in the manner described above Chimney or a stove.

As already indicated, the composted material can be used as fuel for burning or roasting. A Preferred embodiment of the invention relates to a method in which the composted material as Auxiliary fuel is used in burning a combustible inorganic material.

As used herein, the term "combustible inorganic material" refers to any inorganic material Material that can be fired in a kiln to yield a usable fired product. Examples Such combustible inorganic materials include chalk and limestone (calcium carbonate), which are burned into lime

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can be; furthermore bauxitic clays, which can be burned to aluminum, dolomite, which can be burned to magnesium, mixtures of silicic acid-containing materials (in particular loam or clay), chalk or limestone, which can be burned to cement, for example to Portland cement. _:

It has already been suggested, shredded or trash Similar waste as an auxiliary fuel in the manufacture of cement by burning clay-chalk ™ or limestone mixtures to use, this process not only to eliminate the waste, but also to save the conventional Fuel in the burning process leads. However, since its water content is relatively high, for example between 30 and 50 GeWo%, shredded household waste is often difficult to handle Material, as there are clogging problems in the processing equipment "There is an added disadvantage, that processing such a material is quite uncomfortable. Such material also generally has different ones Ash content, so that there are problems in controlling the process, because of the composition of the cement burning material Everything can vary so widely that inferior products are created. In contrast, you can use the relatively dry, composted product, which is used as fuel according to the invention, much lighter bypass. The problem of quality control of the fuel can be solved according to the invention in that the the composted end product is subjected to an air classification, whereby the ash content is reduced and thus the variable

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Factors are reduced.

To drive the moisture out of the compost material, which is used as fuel in a kiln is to accelerate, the composting device can favorably in an area of the burning plant with high Temperature be arranged, for example in the vicinity of the cooler, v / o ambient temperatures in the order of magnitude between 35 and 65 ° C. If you have the composting device arranged in this area, then heat losses from the composting device are minimized. The one through the fermentation drum In addition, sucked air has a relatively high temperature, which makes it easier to expel the water vapor will. Alternatively, the air supplied to the fermentation drum can be obtained from the vicinity of the hot end of a kiln pull off. You can also use the exhaust gases from a grate slag cooler, which has the additional advantage of that the fine slag particles carried away by the gas are stored in the composted product and with it in the kiln be returned.

The fuel produced according to the present invention is in many ways comparable to solid fuels of low calorific value, such as coal of low calorific value Calorific value or with lignite. For example, it can have a calorific value between 3000 and 5000 calories per gram. The composted product exiting the fermenter has a relatively high ash content (e.g. it contains 20 to 30% by weight of ash based on the dry matter). This is particularly due to the fact that it is made from a starting material

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which already contains incombustible material, such as Ashes, small pieces of metal or small pieces of glass. This ash content of the product can be caused by the subsequent air classification can be reduced. For certain uses (for example, in the manufacture of Cement), however, the ash can make a valuable contribution to the end product of the process.

However, the removal of at least part of the ash increases the calorific value of the product accordingly. The cost of the Carrying out the ash separation are often acceptable from this point of viewο It may also be desirable to have a To achieve end product with a substantially constant ash content.

One can increase the calorific value of the composted material produced according to the invention by the addition of hydrocarbon oils, for example, by the addition of waste hydrocarbon oils, _t of oil or oil refined in part, for example, by adding up to 15 wt.% Of these substances. This can be achieved simply by mixing the composted product with the hydrocarbon oils, but it is advantageous to mix the hydrocarbon oils with the materials to be treated for this purpose, i.e. with the mixture of organic waste material and water, partially dewatered sewage sludge or raw sewage sludge. In this way, the hydrocarbon oil is absorbed by the fibrous components of the organic waste material. If these are broken up during the composting process, then the oil they contain will spread out-

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the pieces in the composted product and thus result in a easy to handle product. By adding hydrocarbon oils to the product composted according to the invention it not only increases the calorific value of the product, but also becomes an advantageous and elegant method for The use of hydrocarbon oils is imperative, for example waste oils, the disposal of which in the past has been extremely important was problematic.

The composted product can still be mixed with solid fuels, making an end product with one results in a higher calorific value. For example, the product can be mixed with small parts of washed charcoal (e.g. with Particles that are 2.5 cm or less in diameter). This results in a product that is compared to the Coal causes slightly lower costs per unit of heat generated. This procedure can be particularly useful when wet or use low volatility coals beneficially, of which it was previously believed that they were difficult to use. The ratio of the composted product and the solid Fuel can vary within wide limits.

The following examples are given to illustrate the present invention.

example 1

Two samples of 400 kg each were taken from the shredder of a waste treatment plant. These samples had the the following basic properties compiled in Table 1.

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Sample A

Sample B

Moisture content (in% by weight) on receipt

Calorific value (dry matter)

Ash content (of the dry matter in% by weight)

24.8

27.6 cal / gm 3100 cal / gm 31.4

32.4

The composition of the two samples is given in Table 2.

TABEL 2 Weight% VoI. % sample B. Sample A 18.2 6.4 Weight% Vol.% Components 35.8 69.9 17.5 6.0 Dust and ashes 4.1 6.2 36.4 71.1 Paper and cardboard 8.2 6.0 3.7 5.8 plastic ίο, ο 3.2 8.4 6.0 metal 18.4 5.4 10.5 3.3 Glass 2.4 1.5 19.0 5.6 Organic material
(Vegetables etc.) 2.2 1.4 2.0 1.2 textiles 2.5 1.0 various

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The two samples of the shredded waste were then completely mixed together and four samples of 25 kg each (Sample A) were taken from the mixture »In addition, four 25 kg samples (sample B) were taken from the mixture, from which Metal and glass were picked out by hand.

Two samples of digested sewage sludge and two samples of raw, undigerated sewage sludge were analyzed. The results are given in Table 3.

TABLE 3

Digested Undigerated Sample B Sewage sludge Sewage sludge Sample A Sample B Sample A 81, 4 Moisture salary 68.0 72.5 76.8 26.2 (in% by weight) ash 29.4 27.6 25.6 (in% by weight of 7100 Dry matter) calorific value 4850 4950 6700 (the dry matter in cal / gm)

The two samples of the digested sewage sludge became complete mixed together, the same was done with the two samples of the undigerated sewage sludge. Then samples of 5 kg and 2.5 kg of each became complete

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mixed with waste samples A and B, respectively, resulting in the following mixtures.

TABLE 4

Mixture waste sewage sludge

digested undigerated

5 kg

2.5 kg

5 kg

2.5 kg

5 kg

2.5 kg

5 kg

2.5 kg

1 A. (25 kg) 2 A. (25 kg) 3 B. (25 kg) 4th B. (25 kg) 5 A. (25 kg) 6th A. (25 kg) 7th B. (25 kg) 8th B. (25 kg)

Each of the mixtures was then placed in a rotating drum for 48 hours composted, and the water content, ash content and calorific value of each of the composted products were determined. The results are given in Table 5.

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Water content
Compost
(Wt.%) 2 TABLE 5 Calorific value of
Compost
(in cal / gm of
Dry matter) compost
the end
mixture 8.4 the ash content of the
Compost
(in% by weight of
Dry matter) 4050 1 9.2 31.0 3800 2 14.6 30.5 4600 3 11.4 11.0 4750 4th 10.2 11.4 4300 5 10.4 28.5 4300 6th 12.5 28.0 4950 7th 14.8 9.0 5100 8th 9.5 example

1100 tons of household waste with an average water content of 30% by weight were sorted, with 300 tons of waste being sorted out that were larger than 7.5 cm (the average The water content of these larger parts was 15% by weight). The remaining 800 tons of waste were over a Period of 16 hours together with 110 tons of a drained, Digested sewage sludge with a water content of 80% by weight in a rotary composting plant of the "dano" type introduced. The residence time of the material in the fermentation drum was 48 hours. It turned out 600 tons of a composted Product with a moisture content of 17.5% by weight,

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an ash content of 24 "7% by weight and a calorific value (the Dry matter) of 3610 calories per gram,

The product was an apparently dry product and could be used as additional fuel in a rotary cement kiln to be burned.

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Claims (17)

Patent claims: 1. Fuel, characterized in that it is a composted product made from solid, organic waste • with a water content of less than 20% by weight and comprises a dry matter calorific value of at least 3000 calories per gram. 2. A method for producing the fuel of claim 1, characterized in that one solid organic waste is composted to produce a compost product with a water content of less than 20% by weight obtain. 3. The method according to claim 2, characterized in that that the waste is composted to the extent that a product with a water content between 10 and 20 % By weight, preferably between 15 and 20% by weight. 4. The method according to any one of claims 2 or 3, characterized in that the organic waste in a rotating drum is composted. 5. The method according to claim 4, characterized in that that the organic waste averages between Remains in the rotating drum for 12 and 48 hours. 6. The method according to any one of claims 2 to 5, characterized in that the organic waste before Composting is sorted. - 32 - 709828/0663 A 42 154 b u - 163 26 -Π778 December 22, 1976 - 7. The method according to any one of claims 2 to 6, characterized in that the organic waste before Composting is crushed. 8. The method according to any one of claims 2 to 7, characterized in that the organic waste in a Mixture is composted with sewage sludge. 9. The method according to claim 8, characterized in that the mixture of organic waste and sewage sludge Has a water content between 25 and 50% by weight, preferably between 30 and 45% by weight. 10. The method according to any one of claims 2 to 9, characterized in that the composted waste hydrocarbon oils can be added. 11. The method according to any one of claims 2 to 10, characterized in that a solid, particulate Fuel is mixed with the composted waste product. 12. Device for performing the method of claims 2 to 11, with one of the solid organic Waste-absorbing, rotatable drum that has mixing elements inside for ventilation and / or by mixing the comprises waste located in the drum and a drive for rotating the drum, characterized in that that at least some of the mixing elements are designed as hanging chains (19, 20). - 33 - ORJQINAL IMSPECTED 709828/0863 A 42 154 b u - 163 26 ^ 778 Dec. 22, 1976 - ys - * " ^v ~ ~ '' ^J , 3 13. A method for generating heat , characterized in that the fuel produced by the method described in claims 2 to 11 is burned. 14. The method according to claim 13, characterized in that that the composted product is burned in the furnace of a steam generating plant. 15. The method according to claim 13, characterized in that that the composted product in a kiln of an inorganic material to be burned, preferably a mixture of chalk and lime or limestone to make cement, is burned. 16. The method according to any one of claims 13 to 15, characterized in that the composted product before the burning of which is added to hydrocarbon oil. 17. The method according to any one of claims 13 to 16, characterized characterized in that the composted product is a solid, particulate fuel before it is burned is admixed. / NSPECTED 709828/0663