DE2445391A1 - METHOD FOR WET OXYDATION OF ORGANIC SUBSTANCES AND DEVICE FOR CARRYING OUT THE METHOD - Google Patents

Description

Process for the wet oxidation of organic substances and device for carrying out the method

The invention relates to the oxidation of organic waste substances in aqueous medium, hereinafter referred to as wet oxidation, and is particularly concerned with one Process for the oxidation of combustible organic substances dissolved or dispersed in an aqueous system by treating with an oxygen-containing gas at elevated pressure and temperature during a for substantial reduction in chemical oxygen demand for a sufficient period of time, as well as with a reactor to carry out of the procedure.

The wet oxidation is a form of incineration, in which organic waste substances or other substances in liquid Solution or suspension, the liquid usually being water for practical reasons. the Wet oxidation can only occur at a corresponding rate at elevated temperatures, namely considerably above normal Boiling point of water lying, can be carried out, so only at a far above atmospheric pressure Pressure. For this purpose, the slurry or solution is used

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the combustible organic substance enclosed in a reactor, in which the substances to achieve the desired oxidation rate are below the desired Temperature and the desired pressure can be maintained.

Wet oxidation is a safe, effective and economical method of destroying or disposing of water-containing waste, such as sludge, sewage sludge and other organic waste materials, without the need for expensive evaporation or dewatering, which is required using current incineration techniques as a pretreatment of the waste . For example, in the case of waste water disposal by incineration, the water content of the waste water or sewage sludge, which is the deposited or filtered waste substances and which normally contains more than 90 ° ß> water, must be reduced considerably before the incineration can be carried out. In this way, a large proportion of the energy required for destruction by incineration is only used for drainage and a large part of the space, manpower and technical equipment is tied up in handling the material to be treated for water removal.

Wet oxidation is also more toxic and harmful for use in disposal. 'more organic Substances such as organic plastics, explosives and similar combustible organic substances, well suited without the risk of air pollution or explosion, as oxidative combustion or Oxidation can be regulated and carried out under water.

The amount of the combustible organic substance suspended or dissolved in the aqueous medium is generally defined than the $ 100 burn

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theoretically required amount of oxygen with COD (chemical oxygen demand). In a similar way, BOD increases the biological oxygen demand in Decomposition of organic matter in a biological way. As a measure of the separation or degradation of organic The percentage reduction in COD or BOD applies to a chemical or biological substance. For example refers to a 20 $ reduction in COD from the deposition of contained organic matter in a Amount that decreases COD by $ 20. A $ 75 reduction of COD means the deposition of chemically oxidizable organic substances in an amount that allows the Decreased oxygen demand by $ 75. A $ 100 reduction of COD would mean that oxidizable organic substance from solution or suspension is essentially completely was eliminated.

Wet oxidation is a chemical oxidation process in which combustion progresses at different speeds, depending, in general, on the concentration of the combustible substances in the aqueous solution or suspension, the oxygen circulation in the system and the size of the molecules of organic matter. It is particularly dependent on the temperature and the pressure at which the wet oxidation reaction occurs is carried out. In general it can be said that organic macromolecules react more easily than molecules of lower molecular weight, with the greatest difficulty being with the lower forms of organic Oxidation products, for example with acetic acid, occur. It follows that the combustion is initially progresses faster as long as the macromolecules, which make up the majority of the initial liquid, oxidized and split up are experienced to parts of lower molecular weight, which become more and more pronounced Oxidation rapidly accumulates in the partially oxidized aqueous medium. Thus, the wet oxidation slows down with it increasing concentration / ^ fP dissolved in the aqueous media or suspended organics of small molecular size.

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Perhaps more important is the temperature at which the oxidation reaction is carried out. In.der past been achieved essentially complete destruction by wet oxidation only at very high temperatures of about 288 ⁰ O and at correspondingly high pressures of between about 105 and about 141 kp / cm. This has limited the use of the wet oxidation process on an industrial scale in the disposal of ordinary sewage sludge because of the need for equipment and materials that can withstand such reaction conditions, and because of the corrosive nature of the substances to be treated therein.

The use of the wet oxidation process for elimination of wastewater and sewage sludge takes place on an industrial scale in accordance with the "Zimpro" process U.S. Patents 2,665,249, 2,824,058, and 2,903,425.

The "Zimpro" process is essentially a batch process using a tower-like reactor which is charged with the hydrous waste, which usually contains the organic matter in an amount in the range of 3 to 5 gen.-fo , and with oxygen is made up in an amount ranging from 1 to 2 wt .- $. The oxygen is usually in the form of air.

The reaction components are pumped into the reaction tower in such an amount that it is filled with and remain therein for a specified period of time at elevated temperature and pressure.

For the destruction of organic waste substances in the reactor at a temperature is usually run in the range of about 260 to about 288 ⁰ C and at a pressure usually in the range of about 105 to about 141 kp / cm. the

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Maintaining these extremely high temperatures and pressures is expensive. Because of the aggressiveness of the substances under operating conditions The maintenance costs are high and the service life of the equipment is proportionate short.

A modification of the "Zimpro" process with the aim of his Application at lower temperatures and pressures results in a relatively low efficiency of the process out, in which there is essentially a dewatering of the sewage sludge and in which there is a reduction in the COD can achieve a maximum of about $ 70. The solid residues contain much less biodegradable organic. Substance and are sterile, the remaining However, liquid still has a high demand for oxygen and its elimination is difficult.

It is the object of the invention to provide a process for wet oxidation of the type described at the outset and a reactor for Implementation of the process to create the implementation of the wet oxidation process at a lower temperature and allow lower pressure and yet with a technically acceptable rate of oxidation or degradation and with which the GSB can be reduced by up to 80 to 90 $ to thereby for the disposal of sewage, sewage sludge or other combustible organic substances at high speed '. and with lower costs for technical equipment and to provide a more effective and economical method for maintaining them.

The invention is explained below with reference to schematic drawings of an exemplary embodiment with further details explained. In the drawing shows:

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Pig. 1 is a plan view, partly in section, of a Reactor for carrying out the process according to the invention,

Figure 2 is a side elevational view of the reactor shown in Figure 1;

3 shows a graph of the rate of oxidation or degradation at different operating conditions.

It has been found that with the combustion of organic substances by wet oxidation the formation of free radicals goes hand in hand. The free radicals formed are able to initiate the oxidation reaction at the reactive sites to catalyze under temperature and pressure conditions that are more favorable than those for oxidative combustion or Oxidation of organic substances in the absence of such free radicals required conditions. Such educated Unfortunately, free radicals have a very short lifespan, measurable in a small fraction of a second, which means it is necessary for the use of free radicals to provide reactive sites for the oxidation reaction and to supply these free radicals quickly after they have formed, thereby creating a kind of chain reaction to create under favorable process conditions.

An effective use of free radicals in the wet oxidation process described is according to the invention by entering of oxygen-containing gas in an area in which the liquid is strongly agitated, as a result of which the oxygen-containing gas is converted into finely divided bubbles, which are immediately and evenly distributed over the mass of liquid and in intimate contact with incendiary bears organic substances come to create active sites for oxidation. At the same time, the most educated free radicals are immediately transported to such active oxidation sites. In this way the oxidizability becomes

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2 AA 539-1

reinforced. As a result, at temperature or temperature and pressure conditions, as previously used, increase the rate of oxidation of the combustible organic substances, or, what is more advantageous, the wet oxidation process can be carried out at a lower temperature or at lower temperature and pressure without reducing the rate of oxidation that is accepted economically carry out. In addition there is the fact that it is freer in the presence of the strong promotion of oxidative combustion Radical is possible to carry out the wet oxidation to a higher percentage reduction of the COD in less time and thus to generate a more purified wastewater that can be safely returned to natural waters or in other ways for irrigation o. The like. Can be used without contamination, odor nuisance or pollution to fear.

Under these conditions, the rate and extent of oxidative combustion of dissolved or diapered organic substances in the aqueous medium are better than or comparable to those at temperatures of about. 288 ⁰ O, and overpressures between about. 105 and 141 kgf / cm can be at temperatures below about 249 C, however above about 204 C and preferably achieve in the range between about 216 and about 240 ⁰ C and at pressures below about 42.2 kp / cm and preferably in the range between about . 35 , 2 and about. 38.7 kg / cm

It is difficult to understand the unexpectedly high reaction rate and the strong percentage reduction in COD at such relatively low temperatures and pressures different to be explained as acceleration by free radicals, which are formed during combustion and act on points that cause oxidation are more accessible. Bs is believed to be the preparation of the bodies for accelerated reaction among the the operating conditions described come about as a result,

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that something exists between the combustible organic substances and the oxygen over the largest possible area what could be described as rubbing or chafing, due to the highly dynamic State of the oxygen-containing gas during stirring and its finely divided state.

The advantages that result from this advantageous solution of wet oxidation in the disposal of sewage, sewage sludge or other organic waste materials are shown using the following example, carried out in a reaction of the type described below.

The reactor is an autoclave with an inlet at its bottom for the introduction of air and an outlet which is spaced from the ceiling such that the volume above the outlet corresponds to about 20% of the total volume of the reactor. The reactor is equipped with a pair of i ^m spacing of stacked impeller rotatable about a vertical axis in the center of the reactor, the stirrer blades protrude from a carrier in the form of a disc-shaped plate down. The inner surfaces of the reactor, with which the liquid comes into contact, are made of a high-alloy nickel steel, titanium or another corrosion-resistant metal. During continuous operation, the reactor is filled with the liquid up to the level of the outlet.

EXAMPLE 1

About the rate of oxidation or degradation and the percentage reduction of the COD between a stationary or stationary system that represents the state of the art and a die To be able to compare the system representing implementation of the invention, at .dem to maximize the chain reaction with formed free radicals the oxygen-containing one

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Gas is introduced at the point with the greatest movement, a non-acidified sewage sludge with a COD of 27,000 mg O ₂ per liter is used. The sewage sludge is kept in the reactor at a temperature of approximately 238 ^° C. and a pressure of a maximum of approximately 38.7 kgf / cm. The air is supplied with a flow rate of about 28.3 Nl / min

via an inlet located at the bottom of the reactor immediately below the lowermost stirrer. in the Process sequence with a stationary system, the stirrers are switched on for 30 seconds after 20 minutes to immediately achieve homogeneity prior to sampling. Otherwise the only movement comes from through the liquid passing air flow, through the development of water vapor and carbon dioxide as combustion products as well as through the Release of heat that is generated by the exothermic combustion process.

In the process sequence representative for carrying out the invention, the stirrers run at a speed of 800 up to 900 rpm.

Samples were taken after 20 minutes and used to determine the rate of wet oxidation over time. 'and the percentage Reduction of the COD to the amount in solution ■ vcn by oxygen or oxidatively combustible organic Substances examined. The graphical representation of the results gave the curves shown in FIG. With The curve drawn in solid lines gives the values for the process sequence with a stationary system, while the curve with The broken line curve indicates the result of the process sequence in which free radicals formed maximum. were used.

By extrapolating the curves it can be seen that the destruction of organic substances initially occurs when stationary System at a rate close to 300 mg / l op per minute,

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in the process flow according to the invention at a rate of

ζ dipkeit

1100 mg / 1 O ₂ per minute takes place, and that the destruction rate or degradation rate after a reduction in COD by 65 $ in the stationary system has decreased to about 100 mg / l O ₂ per minute, which is a value of over 300 mg / l O ₂ per minute for the process sequence according to the invention. During the first 20 minutes, the COD of the constantly stirred sample decreased to A2fo at an average rate of about 550 mg / l, while it took 50 minutes for the stationary system to achieve a corresponding reduction in the To achieve COD.

It can also be seen that the rate curve for the stationary system shows no jump between the rate and Start of the oxidation reaction (with macromolecules) and the rate during the later oxidation phases in which the Liquid has a higher percentage of organic matter with lower molecular weight.

The above information is a theoretical explanation of the reaction that takes place under the conditions as in the older DOS 2 247 841 is assumed.

A reactor in an improved form for the degradation of combustibles contained in sewage sludge or waste organic substances by wet oxidation is in Pig. 1 and 2 as horizontally arranged cylinder 10 of predominant Longitudinal expansion shown. The interior 12 of the reaction cylinder is defined by vertical walls 14,16 and 18 divided into a series of contiguous cells 20, 22, 24 and 26, each in the shape of a section of cylinder exhibit. It is evident that, depending on, to a certain extent, the cylindrical reactor of the desired capacity of the unit can be designed with different dimensions, and that the

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2A45391

Cells in their dimensions or their volumetric capacity can differ from each other, the cells corresponding to the initial stages preferably a larger one Capacity than the others.

Each cell is provided with its own direction of movement, preferably in the form of a stirrer with two disks 28 and 30, which are spaced one above the other are attached to a shaft 32. This is in every cell centrally arranged and rotatable about a vertical axis, wherein the shaft part stored in bearings 34 is led out of the reaction cylinder 10 with a seal and devices, such as pulleys 36, with which the shaft can be set in rotation, for example via a belt driven by a motor. For the drive an electric motor drive can also be provided for each shaft. Each of the disks 28 and 30 has radially directed Blades 37, which protrude from the underside of the disc downwards. When using the stirrer described with It is two disks arranged one above the other at a distance expediently, the lower disc at a level which corresponds to about a third of the cell height, and the other To arrange the disc at a level that corresponds to about two-thirds of the height. However, only one or more than Use two disc stirrers, keeping a distance between the .lower disc stirrer and the cell bottom and between the uppermost disc stirrer and the cell end must be respected. The arrangement of the stirrers is preferably limited to a space which is three quarters the cell height extends below the liquid level in the cell.

The supply of air, oxygen or some other oxygen-containing Gas into the cells in which an oxidative reaction is to take place is through an inlet in Shape of one or more nozzles 38, which the oxygen-containing Gas or air immediately in the area

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in which, caused by the stirrer located furthest down, there is the strongest movement. In the modified embodiment shown, the nozzles 38 protrude from the bottom of the cell upwards immediately below the blade part 37 of the lowermost stirrer, around the air stream or the stream containing oxygen Blow the gas upwards towards the bottom of the stirrer so that the air or the entered Gas immediately the vortex. exposed by the high-speed stirrer is generated., and thereby in

the liquid in

a turbulent flow is distributed immediately. . The nozzles 38 can be congruent with the center of the stirrer or offset from this, but are preferably arranged within the outer boundary of the stirrer, so that they reach into the vortex generated by this. The supply of air or some other oxygen-containing Gas to the nozzle takes place from a manifold 40, which is connected to a compressor or pressure accumulator, so that the air or gas can be introduced under a high pressure which is equal to or preferably higher than the harsh pressure in the reaction cell.

The first cell 20 has an inlet 42 which is located at the end of a tubular body 44 which is connected to a heat exchange 46 in the last cell 26 is in communication to allow the liquid to be introduced into the reactor by heat exchange with the hot liquid and the hot gases that are to be discharged from the last cell, can be preheated. The first cell also has a number of electrical heating elements or heat exchangers 48 through the heat exchange fluid coming from a manifold or distribution box 50 is circulated, with the purpose of supplying sufficient heat to initiate the reaction, and through the exothermic Dissipate heat generated in the reaction, thereby reducing the

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24A5391

To keep the temperature of the substances in the reaction chamber under control. The one referred to as the discharge area last cell has an outlet 52 which communicates with the vapor space communicates in the upper part of the cell in order to discharge vapors, as well as a further outlet 54 which communicates with the liquid space communicates in the lower part of the cell and drains fluid out of the cell.

The cells are. . - "- '> - ·.'. Connected to one another, for example

with a . · Tube 56 extending in the transverse direction from an outlet 58 in the upper part of the preceding cell extends to a downcomer or drainage pipe 60 in the subsequent cell. The drain pipe 60 is oriented vertically arranged. The outlet 58 in each of the preceding cells is located in the upper part of the cell, which thereby into a liquid space which extends up to the level of the outlet, and into one lying above the outlet Steam room is divided. The outlet should be at one level be arranged by at least $ 10, but no more than around 40 $ of the distance, preferably in the range of 15 to 25 $ of this distance is below the cell ceiling by one Create vapor space that is $ 10 to $ 40, preferably 15 to Equals $ 25 of the total volume of the cell.

The vertically arranged hollow drain pipe 60 is in his The length is dimensioned in such a way that openings formed on the upper end piece are in communication with the vapor space of the cell, while the open lower end extends below the liquid level and, during normal operation, into the one in the cell liquid is immersed. The mixture of liquid, gas and steam passing through the connecting pipe 56 flows from a preceding cell into the neighboring cell, thus separates during the passage through one such tubular body so that the gases and steam through the drain pipe up into the steam space of the neighboring

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Cell can flow while the liquid through the drain pipe down into the in the cell Liquid mass flows.

In the embodiment of the modified embodiment shown, the connecting pipe described has the shape a T-pipe section, the drain pipe preferably concentric to and around the stirrer shaft 32 is arranged. The horizontally arranged connecting pipe piece 56 penetrates the cell partition and is on a Intermediate piece of the drain pipe connected. The connecting pipes between the cells are from one cell to the others placed at a slightly lower level to allow flow in the direction from the first cell to the next etc. to favor. The effect of gravity is thus used to control the direction of the flow between the cells it is sufficient if the difference in level is only a few millimeters or more.

The oxidation proceeds relatively quickly, up to about two-thirds of the combustibles initially present organic matter are oxidized, and then drains off at about one-third the rate for the remainder. Thus finds most of the oxidation takes place in the anterior cell or cells.

It was also found that the oxidation reaction, From a qualitative point of view, it takes place in stages via a series of intermediate products. It is believed that the organic substances by hydrolysis and / or oxidation from their initial complex structure into simpler ones Oxidation reaction products with lower molecular weight are converted, for example into lower fatty acids, such as acetic acid. This reaction is going well quickly. The oxidation of the intermediate products to the end product, namely carbon dioxide and water, then proceeds much more slowly in front of you.

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These latter compounds are volatile and tend to change into the vapor phase together with water vapor and permanent gases such as nitrogen, carbon dioxide, and unused oxygen. Let these gases derive from the reactor 10 via the outlet 52 and are finally released into the open air. Before submitting to the atmosphere can recover the residual heat contained in such gases and vapors by removing these gases and brings vapors in a heat exchanger into contact with the material to be treated fed to the reactor, or it energy can be recovered to generate electricity.

The inner walls of the reactor and the internals - 'those of the Liquid and exposed to oxygen under high temperature and pressure are expediently complete made of titanium. However, it is also possible to use other metals and steel that can withstand the corrosive attack under the operating conditions described such as corrosion-resistant steel type 316 »lead-coated walls with protection from acid-proof Stones, lined with charcoal - graphite stones bound with acid-proof putty, such as "C-6" (trade name of National Carbon). '' From a cost point of view and in terms of simplicity of execution the latter materials are preferred for reactors with larger capacities.

The reaction temperature in each of the cells can be maintained within the range of about 204 to about 249 ^{° C.} Within this range, each cell can be kept at the same or a different temperature. The temperature can increase from the first to the last cell to compensate for changes in the reaction rate, but in practice a temperature decrease from the first to the last cell is preferred. It is usually convenient to have a total pressure between about

above

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3.52 and about 14.1 kp / cra above the vapor pressure of water to be maintained at the highest temperature prevailing in the reactor, since this means that the oxygen partial pressures are sufficiently high are available to dissolve sufficient oxygen in the liquid phases without an unnecessary one

Having to accept increases in the cost and complexity of the equipment and operations. at The use of pure oxygen is necessary to achieve the desired solution of oxygen Total pressure usually lower than in systems that work with atmospheric oxygen.

age
The speed of the air or other oxygen-containing gas introduced into the reaction zone is determined to a certain extent by the quality, i.e. the GSB, of the organic waste substances to be treated, the quantity of these substances in volume per unit of time and the desired degree of oxidation . The minimum use of oxidizing gas usually corresponds to the stoichiometric amount required for the oxidation of the combustible organic substances, that is, the amount of oxygen that is necessary to reduce the COD of the material to be treated to a predetermined level. It has been found, however, that even with good utilization of the oxygen in accordance with the practice of the invention, the oxygen input should be between 0.6 to about 2.5 times the amount theoretically required to reduce the COD to zero.

The reaction can or the like at normal pH of the aqueous solution or dispersion of the sewage sludge, sewage. carried out However, under the conditions described, the combustion of the organic substances can be achieved accelerate if the reaction is carried out in an acidic medium, preferably between 1.5 and 7.0 set pH value of the liquid. To this end

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organic or inorganic acids can be used. However, preference is given to adjusting the pH Sulfuric acid used.

The raw sewage or the raw sludge can be introduced directly into the reactor or one or more pretreatment stages including primary sedimentation or sieving for physical separation Eliminate particles over a predetermined size, reducing the BOD by about $ 30 to $ 60. From Solids screened out of the wastewater can be dried and incinerated.

Pretreatment can also include a sedimentation stage for separation into a solid waste water component, which is the sewage sludge fed to the reactors, and in a liquid fraction of suspended pesticides and solution that is biologically, for example through has aerobic oxidation or fermentation treated and results in an activated sludge. After biological treatment The wastewater can be treated by sedimentation to result in an activated or activated sludge that can be used for Part of it can be returned to the primary sedimentation and / or partly to the reactor for wet oxidation.

EXAMPLE 2

This example serves to explain the löBoxydation of a simulated ship sewage in a multi-stage reactor in cell construction of the type described. The wastewater does not undergo any pre-treatment, such as conversion through aerobic microorganisms.

The reactor has a horizontally arranged cylindrical vessel with an inner diameter of about 254 mm and one Internal length of about 1070 mm. The boiler or vessel walls are clad with carbon. The vessel is with three

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Titanium baffle plates or walls divided into four cells of equal size. The connecting pipes between the cells are arranged at a level that results in a vapor space of about 5% of the total volume of each cell. The material to be treated is fed into the first cell via an inlet arranged near the vessel ceiling and discharged from the last cell via an outlet which is located a short distance above the center line. The turbine stirrer, made of titanium in a welded construction, has discs with a diameter of about 76.2 mm and eight blades of about 9.5. 19 mm, which are arranged on the underside of each disk with radial alignment and with an even spacing in the circumferential direction. The lower disk is about a third of the distance from the reactor floor, while the upper disk is about two-thirds of the distance from the floor.

The reactor is charged with a pump according to the pressure barrel system, which is fed into the first cell during a Injection period of 20 seconds of a pumping cycle lasting approximately 2 minutes, one liter of water-containing waste injects. The liquid is passed through a heat exchanger to a correct pretreatment temperature to reach.

To adjust it to an acidic pH, the water-containing waste was treated with sulfuric acid before it was injected into the reactor added in an amount of 6 g / l.

The water-containing waste was obtained by soaking or slurrying the daily waste of a person with about 132.5 1. The waste had the following composition:

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Composition of the material to be treated in the inflow Leftovers

Shells of two eggs

Remnants of the fat used to fry the eggs Coffee grounds from the percolator preparation of

six cups of coffee
Snippets from a steak
Remnants of a head of lettuce

Remnants of a beef and noodle dish Peel of an orange
a third of a slice of bread

Personal care products

Shaving cream from a shave
Toothpaste residues from one-time brushing

Body appearance! Fertilize

A person's feces during a 24-hour period,

(100 to 150 g, estimated)
Urine, about 0.95 1

Water.

about 132.5 1

The analysis samples were taken after two hours of continuous operation with an hourly interval between them.

In the first cell, the material to be treated was kept at a temperature of approximately 243 to approximately 249 ^° C., in the second cell at a temperature of approximately 238 to approximately 240 ^° C., in the third cell the temperature was approximately 221 to approximately 232 ^° C. , and in the fourth cell about 216 to about 227 ⁰ C.

The reactor pressure was increased to about 42.2 kgf / cm at a Maintained water vapor pressure of about 38.7 kgf / cm. the

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Air was supplied with a flow rate of about 136 l / min in equal amounts per cell. The water-containing waste was introduced with a flow rate of 0.433 l / min. the mean residence time per cell was about 15 minutes Speed of the stirrer 1300 rpm.

The analysis of the product streams for COD was in agreement by the procedure of "Standard Methods for the Examination of Water and Wastewaters", 13th Edition.

The following results were obtained: Results of chemical analysis, test 1

sampling Sample COD reduction after η h acceptance point mg / 1 O ₂ of the COD in $ 1 influx 1975 ___ Cell 1 945 52.2 Cell 2 626 68.3 Cell 3 586 70.3 Cell 4 529 73.2 2 influx 1715 Cell 1 850 50.4 Cell 2 559 67.4 Cell 3 503 70.4 Cell 4 407 76.3 2.75 influx 1809 Cell 1 692, 670 61.7 Cell 2 551 69.5 Cell 3 483 73.3 Cell 4 393 78.3

From the table above it can be seen that after a one hour residence time in the reactor there is a 73 to 78 reduction of the COD was reached, whereby in the first cell,

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compared to the rest of the cells, the greatest percentage reduction was achieved.

EXAMPLE 3

In this example, the apparatus described in Example 2 was used to test the effectiveness of the process in the treatment of primary sewage sludge.

The procedure was carried out under the following conditions:

Reactor temperature

Cell 1 about 243 to 249 ⁰ C

Cell 2 about 238 to 243 ⁰ C

Cell 3 about 232 to 238 ^° C

Cell 4

Real gate pressure

Total pressure, maximum water vapor pressure, maximum

Air through s at ζ

of which to cell 1 to cell 2 to cell 3 to cell 4

Speed of the agitators dwell time , total

The primary sewage sludge was acidified with 6 g HpSO per liter.

An analysis of the mixtures in the various cells provided the following information:

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about 221 until 232 ⁰ C approximately 42, 2 kgf / cm ² approximately 38, 7 kg / cm ² approximately 113 l / min-. 33 ok 27 ok 20th ok 20th ok 800 to 900 RPM 64 min

- 22 GSB 45 503 2445391 reduction * mg 0 ₂ / l of the COD in "fo Il Inflow / inlet 40900 Il 57.3 Cell 1 17300 Il 78 Cell 2 9000 Il 82 Cell 3 7400 Il 84.4 Cell 4 6400 84.4 Outflow 6500

From the foregoing it can be seen that the invention provides a method for wet oxidation of sewage sludge or others organic waste material creates, with which a high oxidation or degradation rate at a sufficiently low Allow to reach temperature to the technical implementation with easily available equipment and To enable materials that produce pure wastewater without undesirable contamination or pollution can be returned to the water, and in which the energy made available during the oxidation reaction can be used in the process flow or for »other purposes.

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Claims (6)

PATENT CLAIMS (j). Process for oxidation in an aqueous system dissolved or dispersed flammable organic substances with an oxygen-containing gas at elevated pressure and elevated temperature, characterized in that the oxygen-containing gas in the area stronger Initiates movement and thus the oxygen-containing gas is immediately distributed in small bubbles rapidly in the aqueous system and brings the free radicals formed during the oxidation to the active sites of the substances. 2. The method according to claim 1, characterized in that the oxygen-containing gas in the aqueous medium immediately below the turbine blades a turbine stirrer which is rotatable about a vertical axis and has downwardly protruding stirrer blades. 3. The method according to claim 1 or 2, characterized in that the oxidation is carried out at a temperature performed between about 204 and 249 ° C » 4. The method according to claim 3> characterized in that the oxidation between about 216 and 238 ⁰ C is carried out. 5. Method according to claim 1 to 4, characterized draws that the reaction can be carried out at a pressure of • j about 3.52 to 14> 1 kp / cm above the autogenous pressure. 509814/1046 - 25 - 45 503 6. Device for carrying out the wet oxidation according to claim 1 to 5, characterized by a horizontal elongated reaction cylinder (10,12) with an inlet (42) on one side and an outlet (52,54) at the other end, - vertically arranged walls (14,16,18) for dividing the cylinder into cells (20,22,24,26), the cell (20) at one end having an inlet (42) for introducing the aqueous solution or dispersion organic substances and the cell (26) located at the other end has an outlet (54) for discharging the liquid - a stirrer (28,30,37) in the cells (20,22, 24,2.6) - a feed (38) for continuous introduction of the oxygen-containing gas in cells (20,22,24,26) in an area of strong fluid movement in the cells (20,22,24,26) - and through connecting lines (56,58,60) between the cells going through the walls (14,16,18). 50981 kl 1 046