Multistage filtratin device for the utilization of wastes and purification of waste water

Start of patent duration: 1980 05 15 Longest possible duration:

© Issued on: 1981 01 12 © inventor:

© Dependency: '© Pamphlets considered to delineate the state of the art:

CH-PS 538641 US-PS 3622509 DE-0S2558703

- 2 No. 360445

The invention relates to a method for combined waste treatment and wastewater treatment by adsorption of wastewater constituents of coal materials and combined thermal regeneration of coal and combustion of combustible waste components.

The invention further comprises an apparatus for carrying out this method with a waste water feed having settling tanks, coal and activated carbon coarse and fine filter elements therein, and refuse reducing devices, a multi-reactor splitter having at least one thermolysis reactor and at least one pyrolysis reactor disposed in close proximity to each other, as well as refuse or Filterkohlevortrocknungseinrichtungen.

According to CH-PS No. 5,38641 it is already known in a process for the disposal of solid waste and for the purification of waste water to carry out the purification of the waste water with the aid of coal particles which are obtained by polluting the organic components of the waste. Part of the coal produced is consumed in the combustion stage.

With regard to the pyrolysis, no information is given about the amount of oxygen to be used, based on the organic waste components. Wastewater treatment is carried out by mixing a part of the coal with waste water in designated ponds.

A continuous and rapid throughput wastewater treatment is not guaranteed by this method to a satisfactory extent. There is no possibility of additional treatment of valuable long-chain hydrocarbons present in the carbonization gas. Thus, the throughput speed, the material and the energy balance of this known method can be further optimized.

DE-OS 2558703 discloses a method for combined waste recycling and wastewater treatment. This method works in a relatively simple and economical manner by:

1. the waste water serves as a means of transport for the waste and for its separation into inorganic and organic constituents,

2. The wastewater contaminated with waste is purified by mechanical and adsorptive filtration using normal and activated carbon;

3. a part of the waste or activated charcoal loaded with dirt load is burned and emits the heat required for the thermolysis in addition to a fuel gas;

4. the majority of the dirty coal laden filter coal is thermally decomposed in a thermolysis reactor, thereby regenerating the filter coal and recovering new coal and carbonization gas.

While the latter method has a number of advantages, it is desirable to improve it for optimal energy use. In addition, it is necessary to eliminate disadvantages and difficulties that also occur in the implementation of this method. Thus, when using coal or activated carbon, which was prepared according to the method of the above-mentioned DE-OS, lead to abrasion of the coal, resulting in coal losses, blockages of the filter towers and contamination of the received process water.

The object of the invention is to improve the energy balance of the process by optimizing the use of all energy sources and to ensure the smooth flow of the process, which in particular by the choice of reaction parameters in the reactors of a Mehrfachreaktormeüers and a corresponding treatment or processing of emerging from the Mehrfachreaktormeiler products should be achieved.

The object is achieved according to the invention in a method of the type mentioned in that the waste water is mixed with at least a portion of the shredded waste, a separation into organic and inorganic constituents, the wastewater flow with dissolved and suspended Bestandteüen of the wastewater stream added garbage through a. Two-stage filter is passed, in which non-activated and activated coal are fed in countercurrent to the Müü-Abwasserstrom, filtered wastewater withdrawn and loaded coal, preferably discharged continuously, and wherein fresh solid waste or

- 3 No. 360445 is optionally returned to the wastewater filter zone after their activation, and wherein in the first reactor, which is housed in a Mehrfachreaktormeiler, pyrolysis at oxygen supply in a stoichiometric ratio and at a temperature which does not substantially exceed 800 ° C, is carried out with recovery of a fuel gas and heat, the heat is used to heat the second, housed in Mehrrichtkteileiler reactor, in which reactor, the dirty load saturated filter carbon is treated in an oxygen-free atmosphere, wherein the adhering to the filter carbon contaminant load is decomposed and a hydrocarbon-rich carbonization gas and other coal are obtained, that further at least a portion of the produced in the second reactor orregenerated coal is subjected to a pelletization process, wherein for filtering particularly suitable products are produced, and optionally at least a portion of the formed carbonization gas containing long-chain hydrocarbons is decomposed in a thermal cracking apparatus into short-chain hydrocarbons.

The process step of the thermal treatment in an oxygen-free atmosphere is hereinafter referred to as thermolysis.

The multi-reactor divider provided according to the invention may comprise a plurality of reactors of the type of the first and second reactors, which are preferably continuous rotary kilns. In this case, the first reactor is preferably in the lower part of the Mehrfachreaktormeüers, while the second reactor is preferably located in the upper part of the Meüers above and in the immediate vicinity of the first reactor, so that it can be heated by the latter by convection heating.

In general, the first reactor is used for the pyrolysis of MüU, while in the second reactor, the dirt laden coal is thermolysed. In addition, at regular intervals, the first reactor of the multi-reactor standard can be charged with saturated normal or activated carbon, followed by combustion of the coal contaminated with heavy metals and the heavy metals are removed together with the ash from the reactor. In addition, it is possible to feed the thermolysis reactor (second reactor) with solid, preferably organic Müü or admix the Ofengut MüU.

The method according to the invention is characterized by a particularly advantageous combination of different process steps that allow maximum energy utilization of the processes taking place in the multi-reactor furnace, wherein the heat generation in the pyrolysis or combustion is controlled by dosed oxygen feed, and the remaining energy in the form a relatively hydrocarbon-rich fuel gas is obtained. Depending on the composition of the mill, it may be possible with the aid of the method according to the invention to operate the combined plant for waste recycling and wastewater treatment without the supply of external energy and, in addition, to obtain additional energy.

Due to the particularly favorable conditions selected within the multi-reactor reactor, a solid carbon with good adsorption properties as well as a carbonization gas enriched in hydrocarbons is obtained during the thermolysis step. By Spezieüe processing of emerging from the Mehrfachreaktormeüer burning or carbonization storable energy is obtained, the heat content of the gases by means of heat exchangers in the plant for performing the method according to the invention for predrying, heating the backwash water or for the thermolysis step is used. In addition, difficulties in carrying out the method are avoided by a targeted treatment of emerging from the Mehrfachreaktormeüer fines. According to the invention, in the device defined at the outset, a peeling device connected downstream of the thermolysis reactor (second reactor) for puffing the emerging coal and grinding devices, and a cracking device for splitting the long-chain hydrocarbons contained in the combustion or carbonization gas are provided. Furthermore, it is envisaged to either purify the regenerated solid carbon used in the coarse feeder, ie to bring it into a compact form of desired particle size, thereby avoiding abrasion phenomena of the coal and the resulting contamination of the resulting water, as well as blockages of feeder-carbon-lined feeder elements Pretreatment of the activated carbon to be activated in the fine filler a high surface area, ie herzusteüen with high adsorption capacity. These process steps are explained in more detail below.

- 4 No. 360445

According to the invention, the pyrolysis takes place at a temperature which should not exceed substantially 800 ° C. A particularly preferred temperature range is between 500 and 800 ° C. Occasionally it is also preferred to operate at temperatures in the range of 300 to 400 ° C in order to avoid the evaporation of certain heavy metals.

The oxygen supply to the first reactor takes place in a substoichiometric ratio. The oxygen is metered in such a way that the pyrolysis is maintained, but the temperature is controlled so that it does not substantially exceed 800 ° C. The amount of oxygen supplied is advantageously 30 to 90% of the stoichiometrically required amount of oxygen, preferably 50 to 80%. The amount of oxygen depends on the composition of the kiln to be burned and its degree of moisture.

The fuel gas produced in the first reactor during the pyrolysis is relatively rich in hydrocarbons due to the controlled heat generation; The carbonization gas produced in the second reactor during the thermolysis of the dirt-laden filter coal or solid waste is particularly rich in long-chain hydrocarbons.

The gebüdete fuel or carbonization can as additional external Energiequeüe for the Thermolyseprozeß or as fuel for a separate Boüer, gas combustion device, preferably an internal combustion engine, or the like. be used.

In addition, it is possible to treat the smoldering gas in a cracking apparatus to split long-chain hydrocarbons into short-chain molecules, which are again directly used in internal combustion engines, turbines and the like. can be used, or after their liquefaction represent an easily storable energy source.

According to the invention, it is advantageous to sufficiently cool the gases leaving the high-temperature zone in order to liquefy them, where appropriate a separation into liquid nitrogen and a liquid, combustible, nitrogen-free gas, for example methane gas.

In a preferred embodiment of a cracking apparatus according to the invention which operates with high efficiency, the splitting of the long-chain hydrocarbons into short-chain hydrocarbons takes place in a low-oxygen high-temperature zone at a temperature of at least 1300.degree. The cracking of the long-chain hydrocarbons can also be carried out in the said apparatus with the exclusion of oxygen, so that no combustion or oxidation of the resulting gas takes place.

The said high-temperature zone is produced within the cracking apparatus by incorporating flammable substances such as wood or coal, for example solid carbon, into a vertical vessel, burning them at the lower end of the vessel by injecting a metered amount of oxygen, and the fuel gas in the downward direction is passed through the device, wherein the amount of oxygen is metered so that a controlled combustion of the substances and the generation of the desired temperature is ensured.

The combustible substances are introduced into the device in sufficient quantity u.zw. such that, during operation, a part of these substances has a relatively low temperature, the solid and liquid substances entrained by the gases adhering and / or passing through the substances with a low temperature during the conduction of said combustion or carbonization gases, and as soon as the substances mentioned come to rest in the high-temperature zone, they are burned.

It is advantageous to pass the resulting exhaust gases through a heat exchanger, wherein the heat energy is transferred from the exhaust gases to the heat exchange medium. The heat recovered from the flue gas can either be used to pre-dry solid mash and / or solidified saturated fines, or it can serve to support the pyrolysis or thermolysis steps that take place in the multi-reactor furnace. In addition, the heat recovered from the exhaust gas can be used via a second heat exchanger to heat the water used to backflush the saturated activated carbon to facilitate the desorption of the leached matter adhering to the activated carbon. In addition, it is advantageous to direct the exhaust gas to remove techenartigen impurities by a carbon fume.

According to the invention it is provided to treat spezieü the solid carbon produced in the second reactor in order to avoid difficulties that may occur during the course of the process due to Kohleabriebs. This is the regenerated coal, which is relatively soft and strong

Has different particle size, according to one of the conventional methods, optionally under

Use of a binder, pelleted. It is necessary, for example by means of a sieve, the fine

To separate coal particles and the coal dust, which are then fed to the pelletizer, and as pellets the sieve residue, ie the coarser coal particles can be added. This

Mixture then serves to fill the coarse filler elements (first filtration section).

For the production of activated carbon, the regenerated coal is pretreated according to the invention in order to give it a sufficient hardness and a reasonably uniform particle size.

For this purpose, the coal obtained in the second reactor is finely ground and mixed, for example, with tar or pitch in a ratio of 10: 1 to 5: 1. This coal / tar or pitch mixture is then compacted using high pressures, preferably 981 to 1961 bar, and at temperatures just above the softening point of the particular tar or pitch. Subsequently, the resulting coal / terr or pitch mixture is ground down to the desired particle size. This can preferably be done by means of a roller mill to keep the fines as low as possible 2U. Of course, other grinding equipment, such as whisk mills can be used.

The particle size to which the filter carbon is ground down, depends on the intended use: activated carbon, which is used for the liquid purification, should preferably have a particle size between 0.5 and 1.5 mm. The activated carbon used for gas purification preferably has a particle size of 2 to 3 mm.

If the coal to be activated later is used exclusively for gas purification, the following method is applicable: The coal obtained from the second reactor is finely ground, mixed with tar or pitch in the ratio 10: 1 to 5: 1 and then at high pressures, preferably 981 bar, and pressed at temperatures which are just above the softening point of the tar or pitch used, by means of extruders directly to moldings of the desired size.

The fragment granules thus obtained or the shaped articles of the desired size can then be activated in an activation device by a method customary in the art with superheated steam or with chemicals. In this case, an activated carbon is obtained with a particularly high adsorptivity. This activated carbon is preferably pelleted in a pelletizer.

The drawings illustrate advantageous embodiments according to the invention, wherein there is no restriction, and will be explained in the following: FIG. 1 Schematic flow diagram of the method according to the invention for combined waste recycling and wastewater treatment; 2a and 2b: Combined method for waste recycling and wastewater treatment according to the invention; FIG. 3 shows a schematic flow diagram of the production route, the use and the regeneration of normal and activated filter carbon according to the invention; FIG. Fig. 4 is a front view, in cross-section, of the multiple reactor divider according to the invention; Fig. 5 side view, in cross-section, of the multiple reactor divider shown in Fig. 4 taken along line 5-5; Fig.6 cracking device according to the invention.

Fig.l shows in a schematic flow diagram the material flow in the treatment of solid and liquid waste in the waste recycling and treatment plant -102- according to the invention. The plant comprises a multi-reactor divider -104- . The solid MüU to be worked up, which among other things, food waste, paper, plastics, oil and tar residues, used tires, wood, glass, ash and the like. is by magnetic tape separation, defibration and flotation in the wastewater pretreated so that it consists of substantially organic components for further treatment. In the multi-reactor furnace -104-, the solid MUU is pyrolyzed in a first reactor in an oxygen-lean atmosphere to form heat, fuel gas and ash.

The wastewater can include both urban wastewater and industrial wastewater. A multi-stage coal feeder -106- is used to clean the waste water so that it can be used at least for industrial purposes. The carbon filter -106- is preferably a two-stage filter consisting of a coarse and a fine filter. The coking coal of the coarse filter is regenerated periodically together with the particles and sludge adhering to the coal in the kiln -104-, ie subjected to a heat treatment with exclusion of oxygen. Coal losses are compensated for by the new and regenerated coal.

2a and 2b, supplemented by Figure 3, show an overview of the procedure of the

Waste Recycling and Wastewater Treatment Plant -102-. A sewage inlet duct -108- leads

- 6 - No.360445

Wastewater via a settling tank -110- and a strainer -112- to the coarse filter -114-. This is followed by the final cleaning of the water in the fine filter -116-, which leaves the system via the outlet channel -118-.

The coarse filter -114- consists of a multiplicity of coarse filter elements -120-, which can leave the coarse filter for regeneration by raising and lowering, or can be returned to it again. Each filter element -120- is filled with normal filter carbon of suitable particle size, preferably with pelleted filter carbon. The coarse filter elements are moved in countercurrent to the waste water flow from the end of the filter -122- to the beginning of the filter -124- during operation.

The fine filter -116- also consists of a series of fine filter elements -126-, which are also moved in countercurrent to the waste water from the lower end -128- to the upper end -130- in stages. The fine filter can be cleaned by backwashing, if necessary in appropriate backwashing devices -134-. Preferably, the backflush water is withdrawn directly from the outlet channel -118- and may be stored for a period in the reservoir -136- equipped with heating coils -138-. The backwash contaminated water flows through the return line -140- back to the sewage inlet -108-. For waste treatment, the solid waste is discharged into a bunker -160-, where by means of a magnetic tape -162-, the conveyor belt -166-, the crushing rollers -164- takes place a first treatment or separation of the waste. In sedimentation tank -110- the substances are separated with a density> 1 and removed with the help of the bucket conveyor -168-. A series of air nozzles -170- ensures a thorough mixing of waste water and waste, which facilitates their separation into organic and inorganic components. A conveyor -132- transports floating organics to the two storage chambers -172- of the multiple reactor splitter -104-. In addition, further garbage can pass continuously through the conveyor belts -174- to the pantries. A conveyor -132- transports floating organics to the two storage chambers -172- of the multiple reactor splitter -104-. In addition, further garbage can pass continuously through the conveyor belts -174- to the pantries. A conveyor -132- transports floating organics to the two storage chambers -172- of the multiple reactor splitter -104-. In addition, further garbage can pass continuously through the conveyor belts -174- to the pantries.

The Mehrfachreaktormeiler -104-, in which at the same time in different reactors, the pyrolysis and thermolysis of waste and / or loaded with dirty load of fine coal takes place, is shown in Figures 4 and 5. Reactors -178- are used to burn or pyrolysis of garbage and / or dirty coal loaded with dirt load. In the reactor -186- the thermolysis of saturated filter coal or garbage takes place.

The housing -222- limits the interior of the kiln -190-. The shafts -224- are mounted on bearings -226- and driven by the drive device -228- with the motor -230-. About the openings -232- for filling and emptying with a door -234- and a door -236- with another device for closing the doors, the furnace material is filled into the reactors or emptied from these. The doors -234 and 236- have the joints -262- on. In addition, the reactors -178- are equipped with the air inlet -238-, the fuel gas vent -240-, the convex sieve -242-. The reactor -178- is also in communication with the gas line -184-, which has the check valve -246-, as well as the cracker -192-, the scrubber -196-, the combustion engine -202-, the generator -204-, and the branch line -248- with the valve -250-.

The refuse bin -252- has the closure plate -254- separating the catchment space -256-. At the lower end of the collection room -256- there is the hinged plate -258- with the thermal insulation -260-.

The downwardly-openable containment space -264- is limited by the hinged plate -266-. After thermolysis or pyrolysis, the solids are discharged from the reactors into funnel-shaped containers -268 and 270-. The latter are equipped with heat exchanger coils -272- and slide -274-. Among the containers -268, 270- is the conveyor belt -276-.

In addition, an air supply in the Meilerinnere -190- via the air inlet line -278- take place with the valve -280-. Above the thermolysis reactor -186- is the gas line -282- with the valve -284-. In addition, the thermolysis reactor -186- is equipped with a heat transfer line -288-.

The carbon formed in reactor -186- is classified by means of sieve -290- (Fig.3). larger

Coal kitchens can be used directly in coarse filter -114-. The sifted smaller ones

Coal particles and coal dust are pelletized in pelletizer -292- (Fig.3)

- 7 No. 360445 desired Techtegröße shaped. These pellets are also used to fill the coarse filter elements -120. "For the production of activated carbon, the filter coal originating from the reactor 186 is pretreated, ie it is finely ground in a grinding plant, then optionally pelletized and ground again to a desired particle size is carried out in the activating device -294-, which is followed, if appropriate, by another peeping device -296-- The resulting activated carbon serves to join the fine filter -116- or can be used for commercial purposes.

The above statements clearly show that the Müüverwertungs / wastewater treatment plant -102- herzusteüen to the extent necessary for the purification of wastewater and normal carbon coal activated carbon is able to regenerate.

FIG. 6 shows a cracking device -192- according to a preferred embodiment according to the invention. The cracking device consists of a vertical double-walled container in which an inner container - 300 - is suspended from the upper end -302- of an outer, carrying container -304-. The inner container has an upper end -306- which is covered with an openable end plate -308-. The lower end of the inner container -300- has the constriction -310- and the sieve -312-. Underneath is another sieve --316-.

A circular air supply line -318 surrounds the constriction -310--. This air supply line - 318 - has a plurality of air nozzles -320-, which serve to inject combustion air or oxygen into the interior of the container -300 directly through the screen -312-. The pipe -184- introduces the gas to be split into the upper part of the inner tank - 300 - and ends in a downwardly facing hood -322-. The inside of the tank -300 becomes relatively large with a flammable material Gefüüt, preferably wood, u.zw. so that this füüt the Hauptü of the interior between the screen -312- and the gas discharge hood -322--. The wood immediately above the sieve is ignited and oxygen is introduced via the air nozzles for combustion, so that a high-temperature zone is formed, but occupies only a relatively small area above the screen, while the remaining combustible material remains relatively cool inside the container -300. After the high temperature zone has reached the desired temperature, the fuel b2w. Carbonization gas is introduced via line -184 and hood - 322 into the cracking device. In addition, the blower 324 is operated, whereupon a slight vacuum is generated in the outer vessel 304, whereby the gas introduced via the hood 322 passes through the cool zone of combustible material and the high-temperature zone into the annular space 326 - is withdrawn between the vessels via the suction line -328- and the blower -324-. while the remaining combustible material inside the container -300 remains comparatively cool. After the high temperature zone has reached the desired temperature, the fuel b2w. Carbonization gas is introduced via line -184 and hood - 322 into the cracking device. In addition, the blower 324 is operated, whereupon a slight vacuum is generated in the outer vessel 304, whereby the gas introduced via the hood 322 passes through the cool zone of combustible material and the high-temperature zone into the annular space 326 - is withdrawn between the vessels via the suction line -328- and the blower -324-. while the remaining combustible material inside the container -300 remains comparatively cool. After the high temperature zone has reached the desired temperature, the fuel b2w. Carbonization gas is introduced via line -184 and hood - 322 into the cracking device. In addition, the blower 324 is operated, whereupon a slight vacuum is generated in the outer vessel 304, whereby the gas introduced via the hood 322 passes through the cool zone of combustible material and the high-temperature zone into the annular space 326 - is withdrawn between the vessels via the suction line -328- and the blower -324-.

The resulting cracked gas can either be fed directly to an internal combustion engine -202- or liquefied in the liquefaction plant --206- and optionally separated into a gas preferably methane-based and liquid nitrogen.

At periodic intervals, the cracking device is supplied via the cover -308- new combustible material. This supply can also be done in a continuous manner.