Process and installation for the utilization of organic substances

A process and an installation for utilizing organic substances are proposed, in which the substances are correspondingly comminuted and processed by mixing and reaction stages to utilizable compost. The installation essentially comprises a heatable fermenter with a stirrer located therein. In order to obtain an approximately closed process circuit the comminuted substances are supplied as so-called fresh material by a supply shaft to a conveying shaft constructed as a heat exchanger and undergo corresponding heating therein. Through further supply of fresh material the already heated fresh material is supplied to the fermenter and mixed therein by the stirrer accompanied by further heating. The fermented matter formed in the fermenter, on supplying further fresh material, can be admixed in a specific ratio as so-called bacterial inoculum with the fresh material throughout the process circuit. The gases formed during the fermentation process in the tank can either be used in the installation as process energy or can be supplied via a line to another energy supply plant.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The invention relates to a process for the utilization of organic 
substances, as well as to an installation for performing the process, in 
which the organic substances are comminuted and processed by corresponding 
mixing and reaction stages in reaction chambers to a utilizable compost. 
2. Discussion of the Prior Art 
DE-A-31 52 609 discloses a process for the utilization of domestic refuse 
and other organic substances, in which the delivered domestic refuse is 
separated in an associated sorting or grading installation from the 
inorganic substances, such as e.g. glass, plastics, metals, etc. The 
organic substances are supplied by means of a conveyor belt to a metering 
or dosing apparatus and from there to a mixing tank, in which the 
substances are correspondingly mixed by a stirrer, accompanied by the 
supply of liquid. The substances are then supplied via a crusher and 
comminuter to a waiting tank, in which methane gas is supplied to the 
organic substance. The oxygen-freed mixture is subsequently conveyed via a 
heat exchanger into a reaction container, in which the decomposition of 
the organic substances essentially takes place by bacteria. The 
aforementioned process and the installation for performing the same is 
essentially used for the recovery of methane gas by the bacterial 
decomposition of organic waste. 
SUMMARY OF THE INVENTION 
The present invention deals with the problem of an economic reutilization 
of organic substances, such as those caused e.g. by humans and animals, 
the problem of the invention being to develop a process and an 
installation for performing the process, in which the organic substances 
are processed by an effective, environmentally friendly decomposition 
operation to a material, such as can e.g. be processed as an additive for 
compost, garden mould, etc. 
According to the inventive process this problem is solved in that the 
comminuted, organic substances in compressed form are supplied as fresh 
material to a conveying shaft constructed as a heat exchanger and are 
heated therein to a process temperature dependent on the fresh material, 
that by further supply of fresh material to the conveying shaft 
simultaneously the already heated fresh material is supplied to a heated 
fermenter for a fermentation process and is mixed by a stirrer, 
accompanied by the simultaneous removal of the gases which form and, up to 
the end of the overall process, the fermented matter produced in the 
fermenter is, as desired, admixed as a bacterial inoculum in a specific 
ratio with the fresh material suppliable to the conveying shaft. 
The inventive installation for performing the process comprises a tank or 
fermenter and a stirrer located therein and is characterized in that a 
supply shaft and a heatable conveying shaft, as well as a correspondingly 
constructed discharge apparatus are provided, being connected to the 
container or fermenter in such a way that at least the supply shaft and 
the conveying shaft form together with the fermenter a closed process 
circuit, which is controllable for a predetermined supply of fresh 
material, as well as fermented matter as a bacterial inoculum by means of 
correspondingly positioned locks or sluices.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 1 shows as a first embodiment an installation substantially 
represented as a flow diagram and given the overall reference numeral 100, 
whilst FIG. 2 shows a portion of the installation 200. The two 
installations 100 and 200 constructed for the processing and utilization 
of organic substances are described in detail hereinafter. Subsequently a 
description will be given of the operation of the two installations 100 
and 200. 
The installation 100 essentially comprises a sorting or grading apparatus 
10, a comminuting apparatus 20, a supply shaft 35, a discharge apparatus 
50, a conveying shaft 60, a tank or fermenter 70 equipped with a stirrer 
75, a boiler 85 associated with the fermenter 70 and a tank 80 constructed 
as an intermediate gas reservoir. The aforementioned components are 
described in detail hereinafter. 
The sorting apparatus 10 has an e.g. container-like collecting station 11, 
as well as correspondingly associated tanks 12,13 and 14. In the 
collecting station 11 the substances which may be e.g. supplied in plastic 
bags or loose are sorted by not shown means or also manually into organic 
and inorganic substances. 
The inorganic substances, e.g. impurities and inhibitors are supplied in 
the direction of arrow 12' to the tank 12 and from there to a not shown 
dump for a different processing or destruction. The inorganic substances 
can be destroyed e.g. in a not shown combustion or incineration plant. 
The sorted, organic substances are supplied in the direction of arrow 13' 
to the tank 13 in the form of an intermediate storage means and from there 
in the direction of arrow 14' to the tank 14. However, the organic 
substances can also be supplied directly from the collecting station 11 to 
the tank 14. 
By means of a correspondingly associated conveyor 15 the organic substances 
are supplied by the tank 14 in the direction of arrow 16 to a further tank 
17 in operative connection with a conveyor belt 18. The conveyor 15 is 
e.g. provided with a correspondingly constructed balance 15' by means of 
which the organic substances can be subdivided into specific quantities, 
e.g. into corresponding daily portions for processing. These daily 
portions are then supplied to the tank 17. 
By at least one conveyor belt 18 associated with the tank 17 the organic 
substances are su plied in the direction of arrows 19,19' to the 
comminuting apparatus 20 associated with the conveyor belt. The 
comminuting apparatus 20 comprises a tank 22 having a hopper 21, in which 
in the upper region are located at a limited distance from one another two 
roll bodies 23,24. 
On the outer circumference the roll bodies 23,24 are provided with not 
shown comminuting elements, by means of which the organic substances 
supplied in the direction of arrow 19' and from the hopper 21 inserted 
between the two roll bodies 23,24 undergo a corresponding comminution. In 
not shown manner, the two roll bodies 23,24 are mounted about the 
longitudinal axis thereof in the tank 22 and are driven by correspondingly 
associated, not shown driving motors or the like in contrarotating manner 
in the direction of arrows 23',24'. 
In the lower region of the tank 22 is positioned and mounted at least one 
conveyor screw 25 driven by an associated motor 26. The conveyor screw 25 
conveys and compresses the comminuted organic substances into a sluice or 
lock-like chamber 27 of the tank 22. The lower region of the chamber is 
closed by a closing element 28 constructed in slide-like manner and 
operable by a first piston-cylinder unit 29. The chamber 27 and the 
closing element 28, as well as the piston/cylinder unit 29 together form a 
first sluice or lock designated 30. 
The first sluice 30 is connected to the channel-like supply shaft 35, which 
comprises a first portion 31, a second portion 32 connected in not shown 
manner thereto, as well as a third portion 33. In the first portion 31 of 
the supply shaft 35 is located a thrust element 39 in operative connection 
with a second piston/cylinder unit 38 and which by means of the latter is 
arranged so as to move in the direction of arrows X,X' in the supply shaft 
35. The diagrammatically represented thrust element 39 is e.g. constructed 
as a piston pump and in not shown manner is operatively connected to a 
correspondingly associated hydraulic unit 36 and to a drive 37 via a line 
37'. 
The thrust element 39 is displaceably arranged in linear manner in the 
supply shaft 35 and by means of corresponding, not shown control elements 
integrated in the drive 37 can be positioned in different positions for 
different functional steps. The individual positions A,B,C,D and E of the 
thrust element 39 in the shaft portions 31,32, as well as in a shaft 
portion 45 of the discharge apparatus 50 are indicated by the thrust 
element leading edge 39' shown in broken line form. The individual 
positions A to E will be described in greater detail hereinafter in 
conjunction with the operation of the overall installation 100. 
At one end of the second shaft portion 32 is provided a connecting piece 
32' and spaced from the latter the third, upwardly sloping shaft portion 
33. Considered in the axial direction, the discharge apparatus 50 
constitutes the extension of the portion 32. A second sluice 40 is 
arranged on the third, upwardly sloping shaft portion 33 and comprises a 
second piston/cylinder unit 41 and a closing element 42 in operative 
connection with the latter. Between the connection of the first sluice 30 
and the second sluice 40 a venting and ventilating valve 43 is located on 
the second shaft portion 32. 
The discharge apparatus 50 comprises a pivotably mounted flap 46 positioned 
between the second shaft portion 32 and the shaft 45 and which is 
pivotable by a third piston/cylinder unit 47 from the represented position 
in the direction of the arrow 46'' into the position 46' represented by 
the broken lines. By means of the pivotably mounted flap 46 on the one 
hand the supply shaft 35 can be connected to the shaft 45 of the discharge 
apparatus 50 and on the other hand the supply shaft 35 can be connected to 
the shaft portion 33. 
The discharge apparatus 50 comprises the shaft 45 provided with a venting 
and ventilating valve 48 and further shaft portions 45' and 45" arranged 
in not shown manner thereon. Between the two shaft portions 45',45" is 
provided a third sluice 55, which is provided with a closing element 52 
operable by an associated piston/cylinder unit 51. With one shaft portion 
45' constructed as a draining element is associated a reception tank 53 
and with the second shaft portion 45" is associated a reception tank 54 
for the drained fermented matter. 
To the third, upwardly sloping portion 33 of the supply shaft 35 is fixed 
in not shown manner the conveying shaft 60. The conveying shaft 60 which 
is essentially constructed as a heat exchanger comprises a first, a second 
and a third shaft portion 61,62,63. With the third shaft portion 63 the 
conveying shaft 60 is fixed to a filling connection 64 of the tank 70 
provided with a flange 64'. On the second and third shaft portions 62,63 
is provided a heatable jacket 65 which, accompanied by the interposing of 
a pump 67, is connected via lines 66,66' to the boiler 85. 
The stirrer 75 is located in the preferably e.g. horizontally positioned 
tank 70. The stirrer 75 comprises an axle body 69 axially passing through 
the tank and which is correspondingly rotatable about its longitudinal 
axis on the not shown side walls of the tank 70. The axle body 69 is 
provided with several, axially and radially reciprocally displaced 
stirring elements 71,72,73 and 74, which are fixed in not shown manner to 
said axle body 69. 
At at least one end passing through the tank side wall, the axle body 69 is 
operatively connected with a correspondingly associated and constructed 
drive 76. By means of the drive 76 constructed e.g. as a piston drive and 
operatively connected via a lever bar 76' to the axle body 69, the stirrer 
75 is driven in the direction of arrow R about the not shown or designated 
longitudinal axis of the axle body 69. 
On the tank 70 is also provided a heatable jacket 82, which is connected 
via lines 81',81" and an interposed pump 81 to the boiler 85. With the 
boiler 85 is associated a tank 83 (oil tank), from which fuel is 
correspondingly supplied via a line 84' and accompanied by the interposing 
of a pump 84. 
At its top the tank 70 is provided with at least one connecting piece, to 
which is connected a line 77' linked with a safety device 79. The safety 
device 79 e.g. constructed as an overpressure and underpressure valve is 
connected via a line 79' to the intermediate gas tank 80 for the supply of 
gaseous fuel via a line 80' and accompanied by the interposing of a blower 
78 and which is connected via a line 78' to the boiler 85. The gas in the 
tank 80 can also be supplied via a line 80" to another, not shown energy 
supply installation. 
In the lower region the tank 70 is provided with at least one outlet or 
discharge connection 57, which is connected in not shown manner to a 
correspondingly associated and constructed connecting piece 32' of the 
shaft portion 32. 
It is pointed out here that the tank or fermenter 70 is preferably 
horizontally positioned in order to obtain an optimum process sequence, 
the filling connection 64 positioned approximately tangentially in the 
upper region of the tank 70 being located at one end and the outlet 
connection 57 in the lower region of the tank 70 is positioned at the 
other end. The stirring elements 71,72,73 and 74 arranged in reciprocally 
spaced manner on the axle body 69 are so constructed and displaced with 
respect to one another that during the stirring and mixing process the 
fermented matter is conveyed from one end of the tank 70 in the direction 
of the outlet connection 57 located at the other end thereof. 
FIG. 2 shows as a second embodiment a portion of the diagrammatically 
represented installation 200. The elements not shown in FIG. 2 are 
constructed and positioned in substantially the same way as in the 
installation 100 described relative to FIG. 1. 
The installation 200 comprises a first and a second conveyor belt 118, 
118', an interposed comminuting apparatus 120, a supply shaft 135, a 
conveying shaft 160, a tank or fermenter 170 with a heating jacket 182 and 
a discharge apparatus 150 associated with said tank 170. The tank 170 
contains a stirrer 175, which is constructed substantially identically to 
the stirrer 75 described relative to FIG. 1. The stirrer 175 is 
operatively connected to an axle body 169 driven in rotary manner about 
its longitudinal axis. 
With the first conveyor belt 118 is associated a tank 117 from which the 
organic substances are supplied in the direction of arrows 119 and 119' to 
the comminuting apparatus 120 provided with two contrarotating roll bodies 
123,124. The comminuted substances are supplied to a tank 117' and from 
there via the second conveyor belt 118' to a correspondingly constructed 
collecting tank 127 in accordance with arrow 119". 
The collecting tank 127 is flanged in not shown manner to a portion 132 of 
the supply shaft 135. With the collecting tank 127 is associated a feeder 
149 operable by a piston/cylinder unit 148 and by means of which the 
substances are forced into and compressed in the chamber 127'. In a 
portion 131 of the supply shaft 135 is provided a thrust element 139 
linearly displaceable in the direction of arrows X,X' and which is 
operatively connected to a piston/cylinder unit 138. 
The supply shaft 135 is flanged by portion 132 to a correspondingly 
associated and roughly vertically oriented portion 162 of the conveying 
shaft 160. A sluice or lock 130 is positioned between the two portions 
132,162 and has a closing element 128 operable by a piston/cylinder unit 
129. 
The conveying shaft 160 e.g. provided with two heated jacket parts 165, 
165' is flanged in the upper region by a portion 163 to a filling 
connection 164 of the tank 170 and in the lower region by a portion 161 to 
a portion 133 of a discharge shaft 145. Between the two portions 161 and 
133 is located a sluice 140, which has a closing element 142 operable by a 
piston/cylinder unit 141. 
The conveying shaft 160 is essentially constructed as a heat exchanger and 
is correspondingly heated by the two jacket parts 165,165' connected via 
supply and return lines 166,166',166" to a not shown boiler. 
In the lower region the tank 170 is provided with at least one outlet or 
discharge connection 157, which is connected to a shaft portion 135'. The 
discharge shaft 145 located on the shaft portion 135' comprises a first 
portion 145' and a second portion 145", whilst between the discharge shaft 
145 and the first portion 145', as well as between the first portion 145' 
and the second portion 145" is in each case provided a sluice 155 or 155'. 
The sluice 155 has a closing element 152 operable by a piston/cylinder 
unit 151 and the e.g. identically constructed sluice 155' has a closing 
element 152' operable by a piston/cylinder unit 151'. 
In the shaft portion 135' and in the discharge shaft 145 of the discharge 
apparatus 150 is provided a thrust element only represented partly by 
broken lines here and which is linearly displaceable for different 
functional steps by a not shown piston/cylinder unit and can be positioned 
in different positions. The individual positions B',C',D' and E' of the 
front portion 139' of the thrust element shown in broken line form in FIG. 
2 will be described in conjunction with the operation of the overall 
installation 200. 
The two aforementioned installations 100 and 200 can be supplied with all 
possible organic substances for utilization and processing and examples 
thereof are given hereinafter: 
green matter, such as e.g. lawn clippings, foliage, shrubs and the like; 
organic waste, such as e.g. obtained in the case of separated or sorted 
refuse collection; 
vegetable and fruit waste; 
kitchen and in particular commercial kitchen, canteen and similar waste; 
waste from slaughter houses, e.g. rumens, intestine contents, etc.; 
waste from the food industry. 
These substances can be supplied to the installations 100 or 200 for 
utilization purposes. 
The tank 70 or 170 is mounted approximately horizontally on two spaced, not 
shown foundations in the axial direction of the particular tank. In a 
preferred arrangement of the tank 70 or 170 on foundations the mounting 
support is provided with a gradient from the filling connection 64 or 164 
in the direction of the outlet connection 57 or 157. 
The essential working steps for the installation 100 will now be described. 
The comminuted organic substance compressed by the conveyor screw 25 in 
the chamber 27 will subsequently be referred to as fresh material and the 
matter obtained after passing through the specific process stages and 
discharged from the tank 70 or fermenter will be called fermented matter. 
In a first phase the compressed fresh material from the conveyor screw 25 
and with the sluice 30 open passes into portion 32 of the supply shaft 35 
and is subsequently conveyed by the thrust element 39 e.g. by a control 
means in operative connection with the sluice 30 in the direction of arrow 
X. This process is repeated e.g. intermittently several times with the 
sluice 40 open and the discharge apparatus 50 closed until the conveying 
shaft 60 constructed as a heat exchanger is filled to roughly in the 
vicinity of the filling connection 64. 
Filling can be monitored by correspondingly positioned, not shown sensing 
elements and the further fresh material supply can be correspondingly 
controlled. Then, with the sluice 40 closed, the fresh material 
particularly located in the vicinity of the heated jacket 65 of the 
conveying shaft 60 is heated. On reaching a given temperature and with the 
sluice 30 closed and the sluice 40 open new fresh material is supplied by 
the thrust element 39, so that simultaneously an approximately equal 
quantity of the heated fresh material in the conveying shaft 60 passes in 
the direction of the arrow Z into the also heated tank 70 and is 
thoroughly mixed by the stirrer 75 in operative connection With the drive 
76. 
The correspondingly controllable process and operating temperature is 
chosen in accordance with the composition of the fresh material supplied 
and in the mesophilic range is approximately 28.degree. to 38.degree. C. 
and in the thermophilic range approximately 50.degree. to 60.degree. C. 
During the mixing process in the tank or fermenter 70, the methane formers 
given off are supplied through the movement of the stirrer 75 to the fresh 
material introduced and consequently the metabolic conversion is 
accelerated. Through the movement and through bacterial decomposition the 
fermenter content (fresh material and fermented matter mixture) is freed 
from organic solids and liquefied, so that there is a volume reduction of 
approximately 35 to 50%. 
The gas formed in the tank or fermenter 70 is supplied via the line 77' 
located on the connecting piece 77 and connected to the interior of the 
tank 70 to the intermediate gas reservoir 80, so that an inflation of the 
fermented matter in the tank 70 is prevented. The gas is supplied from the 
gas reservoir 80 to the boiler 85 for generating energy. The gas formed 
during the fermentation process in the fermenter 70 can consequently be 
advantageously used as process energy for operating the boiler 85. 
However, the gas in the reservoir 80 can also be supplied via a line 80" 
to a not shown energy supply installation. 
In an intermediate phase the thrust element 39 is moved back into the 
position A opening the outlet connection 57 of the tank 70, so that with 
the sluice 30 closed a specific fermented matter quantity can be conveyed 
from the tank 70 as so-called bacterial inoculum into the portion 32 of 
the supply shaft 35. 
The proportional ratio of the supplied bacterial inoculum with respect to 
the fresh material introduced into the portions 32,33 of the supply shaft 
35 is e.g. determined as a function of the composition and characteristics 
of the fresh material and inoculum. 
The bacterial inoculum is forced by the thrust element 39 in the direction 
of arrow X into the position C and to the fresh material located in 
portions 32 and 33 and subsequently is pressed into the conveying shaft 60 
with the sluice 40 open. During this process simultaneously the quantity 
in the conveying shaft is supplied in the direction of arrow Z to the tank 
70, whilst the fresh material compressed with the bacterial inoculum 
during this process is heated in the conveying shaft 60 with the sluice 40 
closed. 
In the final phase, in which the thrust element 39 has moved back in the 
direction of arrow X' into position A, the fermented matter is conveyed 
from the tank into the portion 32 and subsequently is moved by the thrust 
element 39, with the flap 46 open (broken line position) into the 
discharge apparatus 50. During this process the sluice 55 initially 
remains closed, so that in this phase the fermented matter is compressed 
and drained at a predetermined and correspondingly monitored pressure of 
the thrust element 39. The water is received by the associated tank 53. As 
soon as the thrust element 39 has reached the position E, the sluice 55 is 
opened, so that the compressed fermented matter drops into the associated 
tank 54. Prior to the moving back of the thrust element 39 the sluice 55 
of the discharge apparatus 50 is closed again. 
The fermented matter obtained in the aforementioned process can 
subsequently be used as an additive for compost, garden mould, etc. 
Diverging from the working steps described by means of the installation 100 
of FIG. 1, in the case of installation 200 according to FIG. 2 the 
comminuted organic material is substantially directly forced by the thrust 
element 139 into the conveying shaft 160 constructed as a heat exchanger. 
The fresh material compressed by the feeder 149 passes into portion 132 of 
the supply shaft 135 with the sluice 130 open and is subsequently conveyed 
by the thrust element 139, e.g. by a control means in operative connection 
with the sluice 130 in the direction of arrow X. This process is 
intermittently repeated several times with the sluice 140 closed until the 
conveying shaft 160 is filled approximately to the area of the filling 
connection 164. 
The further operating and process steps of the installation 200 are 
substantially identical to those described hereinbefore in conjunction 
with the installation 100 according to FIG. 1. 
In the embodiment of the installation 200 shown in FIG. 2 it is apparent 
that the individual supply shafts 135 and 135' are so separated from one 
another that there is no possibility of a mixing or infecting of the 
substantially sterile fermented matter with the fresh material. 
While the invention has been particularly shown and described with respect 
to the preferred embodiments thereof, it should be understood by those 
skilled in the art that the foregoing and other changes in form and 
details may be made therein without departing from the spirit and scope of 
the invention which should be limited only by the scope of the appended 
claims.