WO2001010977A1 - Method of evaluating gas from a sedimentation basin - Google Patents

Abstract

The invention relates to a method and a device for the disposal and utilization of all sorts of waste materials such as the disposal of industrial, domestic or special waste and related industrial products which have become waste products. The invention also relates especially to the elimination and utilization of gases which are absorbed by cooling water during the rapid cooling of a raw synthesis gas and are released into an area where they are allowed to settle. The waste material which is to be disposed of forms a gas-permeable aggregate (20) in a high-temperature area, wherein a raw synthesis gas is produced. The raw synthesis gas is rapidly cooled, in order to prevent new harmful substances from forming, by spraying cold water, whereupon it is cleansed and the cold water subsequently purified in the sedimentation basin (103). According to the invention, the gases which are released from the cold water in the sedimentation basin (103) are reintroduced into the material cycle or are transformed by heat.

Description

 Process for the recovery of gases from the

settling tank

The present invention relates to a method and a device for the disposal and utilization of waste goods of all kinds, in which unsorted, untreated, any pollutants in solid and / or liquid form containing industrial, domestic and special waste and industrial goods wrecks are subjected to a temperature , In particular, the. Invention for the elimination and recycling of gases "which are taken up by the cooling water during the rapid cooling of the raw synthesis gas that is formed and then outgassed from the cooling water in a calming region of the cooling water. Furthermore, the present invention relates to a device for the above method and to uses of the device and method according to the invention.

The known methods of waste disposal are not a satisfactory solution to the growing garbage problems, which are an essential factor in environmental destruction. Industrial wrecks made of composite materials, such as motor vehicles and household appliances, but also oils, batteries, paints, paints, toxic sludges, medicines and hospital waste, are subject to separate, legally prescribed disposal measures.

Household waste, on the other hand, is an uncontrolled, heterogeneous mixture that can contain almost all types of hazardous waste fractions and organic constituents and has not yet been classified in terms of disposal in relation to its environmental impact.

One of the disposal and recovery methods for waste goods is waste incineration. In the known waste incineration plants, the disposal goods go through a wide temperature field up to approx. 1000 ° C. At these temperatures, mineral and metallic residues should not be melted in order not to disturb subsequent gas generation stages as far as possible. The energy inherent in the remaining solids is not used or is used only to a limited extent.

A short dwell time of the waste at higher temperatures and the high dust generation due to the specification of large amounts of nitrogen-rich combustion air in the uncompressed waste combustion goods favor the dangerous formation of chlorinated hydrocarbons. It has therefore started to subject the waste gases from waste incineration plants to post-combustion at higher temperatures. In order to justify the high investments of such systems, the abrasive and corrosive hot exhaust gases with their high dust content are passed through heat exchangers. With the relatively long dwell time in the heat exchanger, chlorinated hydrocarbons form again, which combine with the dusts that are carried along and ultimately lead to blockages and malfunctions and must be disposed of as highly toxic pollutants. Consequential damages and the costs of their elimination cannot be estimated.

Previous pyrolysis processes in conventional reactors have a temperature range that is similar to that of waste incineration. There are high temperatures in the gasification zone. The hot gases that form are used to preheat the as yet non-pyrolyzed material to be disposed of, cool down in the process and likewise pass through the temperature range relevant and thus dangerous for the formation of chlorinated hydrocarbons. In order to produce an ecologically safe clean gas, pyrolysis gases usually go through a cracker before cleaning.

Together, the above-described combustion and pyrolysis processes have the disadvantage that they occur during combustion or pyrolytic decomposition Mix evaporated liquids or solids with the combustion or pyrolysis gases and discharge them before you have reached the temperature and residence time in the reactor necessary to destroy all pollutants. The evaporated water cannot be used for water gas formation. For this reason, post-combustion chambers are usually installed in waste incineration plants and cracker stages in pyrolysis plants.

From EP 91 11 8158.4 a method for the disposal and utilization of waste goods is known which avoids the disadvantages described above. The waste goods are subjected to a gradual temperature application and thermal separation or material conversion and the solid residues are converted into a high-temperature melt. For this purpose, the material to be disposed of is compressed in batches into compact packages and passes through the temperature treatment stages in the direction of increasing temperature from a low temperature stage in which, while the pressurization is maintained, positive and non-positive contact with the walls of the reaction vessel is ensured and organic components are degassed , to a high-temperature zone, in which the degassed material forms a gas-permeable bed and synthesis gas is generated by the controlled addition of oxygen. This synthesis gas is then derived from the high temperature zone and can be used further. This discharge of the raw synthesis gas from the high-temperature reactor is in turn firmly connected to a gas chamber for rapid gas cooling, which has a water injection device for cold water into the hot raw synthesis gas stream. This rapid gas cooling

(Shock cooling) prevents a renewed synthesis of pollutants, since the raw synthesis gas passes through the critical temperature range very quickly due to the shock cooling and is cooled to a temperature at which the pollutants are no longer re-synthesized. This cold water injection into the raw synthesis gas stream also removes liquid or solid particles carried in the gas stream, so that a well-cleaned raw synthesis gas is obtained after the rapid cooling.

When cooling water is injected into the raw synthesis gas stream, essentially liquid or solid particles are taken up from the raw synthesis gas stream, which are then in a calming zone

(Sedimentation tank), such as a lamella clarifier, can be removed from the cooling water again, so that the cooling water can be conducted in the circuit for cooling the raw synthesis gas stream and for cleaning this synthesis gas stream from liquid or solid particles.

A disadvantage of this method is that the cold water sprayed into the raw synthesis gas stream not only absorbs the liquid components and solid particles in the raw synthesis gas stream, but also gaseous components of the synthesis gas, such as for example, H ₂ S, CO, H ₂ and C0 ₂ , dissolves or disperses in the form of small gas bubbles. The cooling water is then fed into the settling tank to separate the fine particles from the cooling water. However, the gaseous intakes mentioned are gases

Components from the cooling water in turn, so that ultimately gaseous portions of the synthesis gas are carried into the settling tank.

For environmental reasons, it is not possible to discharge these outgassing components directly into the environment.

US Pat. No. 4,141,695 discloses a process for gas purification, in which the quench water is mixed with an aqueous emulsion and an organic extractant and then separated off again in order to remove impurities from the quench water. The quench water prepared in this way can then be used again.

It is an object of the present invention to provide a method, a device and uses thereof with which the constituent elements that outgas from the cooling water in the settling tank can be removed or recycled in an environmentally friendly and cost-effective manner.

This object is achieved by the method according to claim 1, the device according to claim 16 and the use according to claim 27. Advantageous further developments of the method according to the invention and of the Device according to the invention are given in the dependent claims.

The method according to the invention follows on from the method disclosed in EP 91 11 8158.4, the disclosure of this document being hereby completely incorporated into the method and the device

the disclosure content of this application is included. The method described there and the device described there are now further developed according to the invention in that the constituent elements which outgass the cooling water in a calming area are sucked out of this calming area (sedimentation basin, lamella clarifier). As a result, it is now possible to subsequently produce this gas, which corresponds in its composition to the purified crude synthesis gas, in various ways and

Way to recycle. In particular, the degree of utilization of the entire system and the entire process is improved and the environment is spared from the constituents that outgas from the cooling water.

According to the invention, the gas from the sedimentation basin can be fed back into the raw synthesis gas stream, this being possible either on the one hand before the rapid cooling or on the raw synthesis gas stream leaving the rapid cooling. Because that from

Gas that outgasses cooling water has already passed the rapid cooling and has been cooled and cleaned sufficiently to be mixed with the raw synthesis gas stream emerging from the rapid cooling.

Alternatively, the gas emerging from the cooling water can also be mixed with fuel gas with the exclusion of oxygen and then thermally utilized in a combustion chamber.

However, the extraction must be explosion-proof. This also applies to an extraction system Subsequent optional compression of the gas emerging from the cooling water.

The gas escaping from the cooling water is then again particularly advantageously in the

High temperature area of the reactor fed back. To do this, however, the pressure difference between the released expanded gas and the high-temperature reactor must be overcome. Compression of the gas is therefore absolutely necessary in this case.

It is particularly advantageous if fuel gases, for example natural gas or synthesis gas, are mixed with the gas from the sedimentation tank before being fed into the high-temperature range, and then this gas mixture is introduced into the high-temperature reactor via lances.

This last possibility has the decisive advantage that the gases which have escaped are completely used energetically and materially and the reaction gases go through the complete cycle of the process according to the invention. This means that since the exhaust gases from this combustion process are treated both in the high-temperature zone and then go through the rapid cooling and the further purification stages of the process, any emissions containing pollutants into the environment are avoided.

The following are some examples of a method and an inventive method Device will be described.

Show it:

1 shows a device according to the invention;

2 shows a device according to the invention; 3 shows a further device according to the invention.

Process steps 1) to 5) are symbolized in FIG. 1. The waste is processed without pretreatment, i.e. without sorting and without comminution, fed to stage 1), in which it is compacted. The compaction result is considerably improved if pressing surfaces act in the vertical and horizontal directions. A high level of compaction is necessary because the feed opening of the pusher channel, in which process stage 2) takes place, is sealed gas-tight by the highly compressed waste plug.

In stage 2), the highly compressed waste passes through a thrust channel 6 with the exclusion of oxygen at temperatures up to 600 ° C. Organic components of the waste are degassed. The gases flow through the waste in the pusher furnace 6 in the direction of process stage 3). With this flow, they contribute to good heat transfer as well as the intensive pressure contact of the waste with the push oven walls. As a result of the constant pushing of the highly compressed waste, this pressure contact is maintained over the entire length of the furnace and the entirety of the channel surfaces, so that at the end of the waste passage through the push channel the degassing of the organic Substances have largely been completed.

Smoldering gases and water vapor, as it comes from the natural waste moisture, metals, minerals and the carbon of the degassed organics are jointly fed to process stage 3), in which the carbon is first burned with oxygen. The temperatures of up to 2000 ° C. and more that occur here melt the metallic and mineral constituents, so that they can be discharged in a molten state in process step 5).

At the same time, the organic compounds of the are heated over the high temperature range of the glowing carbon bed at temperatures of more than 1000 ° C

Smoldering gases destroyed. As a result of the reaction equilibria of C, C0 ₂ , CO and H ₂ 0 at these temperatures, synthesis gas is formed, consisting essentially of CO, H ₂ and C0 ₂ , which is suddenly cooled to below 100 ° C. in process step 4). The rapid cooling prevents the formation of new organic pollutants and facilitates the subsequent gas scrubbing. After that, high-purity synthesis gas is available for any use.

In the process known to this extent, the high-purity synthesis gas can have a volume flow dependent on the waste composition and amount and also a varying concentration of hydrogen. After the gas scrubbing, the volume flow and the hydrogen content of the purified synthesis gas are therefore true and these values fed to a control. This control now controls, as described above, the supply of oxygen and the supply of fuel, for example natural gas or synthesis gas in process stage 3), in which the previously degassed waste gasifies at temperatures of up to 2000 ° C. by adding 0 ₂ becomes. By changing the fuel input or the oxygen supply, both the volume flow and the hydrogen content of the synthesis gas produced can be influenced.

This regulation therefore provides gas utilization following the gas scrubbing a synthesis gas stream with a controlled constant volume flow and also a controlled constant hydrogen content.

The metals and minerals discharged in molten form in process step 5) are expediently subjected to an aftertreatment with the addition of oxygen at more than 1400 ° C. Carried carbon residues are removed and mineralization is completed. The removal of the solids, for example in a water bath, completes the disposal process. In the granulate obtained after the solids have been discharged into a water bath, metals and alloying elements and completely mineralized non-metals are located side by side. Iron alloys can be deposited magnetically. The leach-proof mineralized non-metals can be reused in a variety of ways, for example in expanded pellet form or - processed into rock wool - as insulating material or directly as pellet for Fillers in road construction and in the production of concrete.

1 further shows typical process data of an exemplary advantageous method implementation in the individual areas. Degassing is a function of temperature T, time, pressure and waste composition.

The composition and the volume flow now depend on the available carbon, oxygen and water vapor. By controlling the amount of available carbon (fuel supply to the gas phase) and oxygen (oxygen supply via oxygen plants in the gas phase) via the regulation, the composition of the synthesis gas, which already has a relatively high quality in the known method, is further increased optimized and is therefore ideal for use eg in gas engines for power generation or for chemical processes.

In Fig. 1, the compression is carried out by a compression press 1, the structure of which corresponds to a scrap press known per se, as is used, for example, for the scrapping of vehicles. A swiveling press plate 2 enables the press 1 to be mixed with waste. A pressing surface 3 is in the left position, so that the loading area of the press is fully open. By swiveling the press plate 2 into the horizontal position shown, the waste is first compacted in the vertical direction. Then the moves Press surface 3 horizontally in the position shown in solid lines and compresses the waste package in the horizontal direction. The counterforces required for this are absorbed by a counter plate, not shown, which can be extended and retracted. After the compression process is completed, the counterplate is extended and the compacted waste plug is pushed into an unheated area 5 of the pushing furnace 6 with the help of the pressing surface 3 moving to the right and the entire contents thereof are accordingly transported on, recompacted and in pressure contact with the duct or furnace wall held. Then the pressing surface 3 is moved back into the left end position, the counter plate is retracted and the pressing plate 2 is pivoted back into the vertical position shown in dashed lines. The compression press 1 is ready for a new loading. The waste compaction is so great that the waste plug pushed into the unheated area 5 of the sliding oven 6 is gas-tight. The pusher furnace is heated by flame and / or exhaust gases that flow through a heating jacket 8 in the direction of the arrow.

When the compressed waste is pushed through the furnace channel 6, a degassed zone spreads out towards the center plane of the pusher furnace 6, favored by the large surface area associated with the side / height ratio> 2 of its rectangular cross section. When entering a high-temperature reactor 10, there is a mixture of carbon, minerals, metals and partially decomposed gasifiable composites which is compacted by the constant pressurization during the passage. before. This mixture is exposed to extremely high radiation heat in the area of the inlet opening into the high-temperature reactor. The associated sudden expansion of residual gases in the smoldering material leads to its fragmentation. The solid piece goods obtained in this way form a gas-permeable bed 20 in the high-temperature reactor, in which the carbon of the carbonized material is first burned to CO ₂ or CO using oxygen lances 12. The carbonization gases flowing through the reactor 10 swirling above the bed 20 are completely detoxified by cracking. Between C, C0 ₂ , CO and the water vapor expelled from the waste there is a temperature-related reaction equilibrium in the synthesis gas formation. This raw synthesis gas is passed via a raw synthesis gas line 100 to a container or chamber 14, in which the synthesis gas is shock-cooled to less than 100 ° C. by water injection. Components entrained in the gas (minerals and / or metal in the molten state) are separated in the cooling water, water vapor is condensed so that the gas volume is reduced and gas cleaning is simplified, which follows the shock cooling in known arrangements can. The shock-like cooling of the

Water used in the synthesis gas stream can, if appropriate, be used again for cooling after purification and consequently be circulated. In the rapid cooling of the raw synthesis gas by spraying cooling water into the raw synthesis gas stream, not only liquid components and solid components (dusts, etc.) are removed from the raw synthesis gas, the cooling water also absorbs gas components from the raw synthesis gas. This is done, for example, by emulsifying the finest gas bubbles in the cooling water or by dissolving gases from the raw synthesis gas. The mineral and metallic constituents of the carbonized material are melted in the core region of the bed 20, which is hotter than 2000 ° C. Due to the different density, they overlap and separate. Typical alloying elements of iron, such as chromium, nickel and copper, form a smeltable alloy with the iron of waste, other metal compounds, such as aluminum, oxidize and stabilize the mineral melt as oxides.

The melts enter directly into an aftertreatment reactor 16, in which they are exposed to temperatures of more than 1400 ° C. in an oxygen atmosphere introduced with the aid of a 0 ₂ lance 13, optionally supported by gas burners (not shown). Carried along carbon particles are oxidized, the melt is homogenized and its viscosity is reduced.

When they are discharged together into a water bath 17, the mineral material and the iron melt granulate separately and can then be sorted magnetically.

The cooling water is from the container 14 via an outlet 102 in a calming area, here one

Lamellar clarifier 103, where the solids contained in it, eg suspended components, settle. zen and removed through a sludge outlet 104. The cooling water purified in this way is re-used for cooling the raw synthesis gas via a water outlet 105 and a water inlet 107 in the container 14 and is consequently circulated.

The cleaned raw synthesis gas leaves the container 14 via a discharge line 101 in order to then be subjected to a fine washing or fine cleaning.

A gas chamber 106 forms in the lamella clarifier 103 above the standing sewage water, into which the dissolved and emulsified gas components of the cooling water outgas. This gas space is connected to a suction and compression device 111 via a gas outlet 110. This suction and compression 111 sucks the gas components which have emerged from the cooling water out of the air space 106 and compresses them in order to bring them to a pressure which is above the pressure in the high-temperature reactor 10. Following the compression, the gas is mixed with a fuel, for example natural gas or synthesis gas, via a fuel feed line 112 and then introduced into the high-temperature reactor via a gas nozzle 113, where it is completely combusted and subjected to the processes taking place in the high-temperature reactor.

The advantage of this return line of the gas is that its combustion gases now also include the cracking stages in the high-temperature reactor and the subsequent ones

Raw synthesis gas scrubbing in the container 14 are subjected again. Overall, it becomes one emission-free disposal and thermal utilization of the gas outgassing from the cooling water.

2 shows a further device according to the invention, in which the same components and components are identified by the same reference numerals. In contrast to the device in FIG. 1, the gas emerging from the cooling water is now collected in the gas space 106 and supplied to a suction and compression device 121 via a gas outlet 120. The constituents which outgas from the cooling water correspond to the synthesis raw gas, so that, as shown in FIG. 2, they are introduced into the pipe synthesis gas stream 100 via a gas supply 122 before the rapid cooling in the container 14. In this case, too, a completely emission-free disposal or recycling of these outgassing components is effected.

Since the outgassing components already

Have passed through rapid cooling, these outgassing constituents can also be fed into the raw synthesis gas stream after the rapid cooling in the container 14 into the discharge line 101 of the cleaned raw synthesis gas for fine washing.

FIG. 3 shows a further device according to the invention, in which the same reference numerals as in FIG. 1 are also used for the same components and elements. In this case, in contrast to FIG. 1, the constituents that gas out into the gas space 106 are fed via lines 130 and 134 to a combustion chamber 131, where they are burned with low emissions under the supply of oxygen 133 and the combustion gases are released into the environment via a chimney 132.

Claims

claims 1.Procedure for the disposal and utilization of waste goods of all kinds, in the unsorted, untreated, any pollutants in solid and / or liquid form containing industrial, domestic and / or special waste as well as industrial goods wrecks of a gradual temperature exposure and thermal separation or material conversion are subjected and the resulting solid residues are transferred to a high-temperature melt, the waste material being compressed in batches into compact packages which Temperature treatment stages in the direction of increasing temperature with at least one low-temperature stage in which, while maintaining the pressurization, positive and non-positive contact with the walls of the reaction vessel (6) is ensured, and with at least one high-temperature zone in which the material to be disposed forms a gas-permeable bed (20) and raw synthesis gas is produced, whereby the raw synthesis gas generated is discharged from the high-temperature zone and shock-cooled by spraying with cooling water and the cooling water in a settling tank (103) is passed, characterized in that the gases escaping from the cooling water in the sedimentation tank are extracted. 2. The method according to the preceding claim, characterized in that the gases emerging from the cooling water in the settling tank (103) are compressed. 3. The method according to the preceding claim, characterized in that the gases emerging from the cooling water in the settling tank (103) are fed to the raw synthesis gas before or after the rapid cooling of the raw synthesis gas. 4. The method according to any one of the preceding claims, characterized in that the gases emerging from the cooling water in the settling tank (103) and extracted gases are mixed with fuel gas. 5. The method according to the preceding claim, characterized in that the fuel gas is admixed with the exclusion of oxygen. 6. The method according to any one of the preceding claims, characterized in that the gases emerging from the cooling water in the settling tank (103) are passed into the high-temperature zone and are converted there energetically and materially. , Method according to one of the two preceding claims, characterized in that the gases emerging from the cooling water in the settling tank (103) are thermally converted in a combustion chamber (103). 8. The method according to any one of the preceding claims, characterized in that the suction and / or compression of the gases emerging from the cooling water in the settling tank (103) is carried out explosion-proof. 9. The method according to any one of the preceding claims, characterized in that at least the low temperature stage is carried out while maintaining the pressurization in positive and non-positive contact with the walls of the reactor vessel (6) with the exclusion of oxygen. 10. The method according to any one of the preceding claims, characterized in that the low temperature stage is run in the temperature range between 100 ° C and 600 ° C. 11. The method according to any one of the preceding claims, characterized in that the high temperature stage is passed through with the addition of oxygen. 12. The method according to the preceding claim, characterized in that the carbon fractions in the bed (20) are gasified by metered addition of oxygen to carbon dioxide and carbon monoxide, the carbon dioxide being reduced in carbon monoxide when penetrating the carbon-containing bed (20) and that hydrogen and carbon monoxide are formed from the carbon and superheated steam. 13. The method according to any one of the preceding claims, characterized in that the high-temperature stage is run through at temperatures of more than 1000 ° C. 14. The method according to any one of the preceding claims, characterized in that the derived synthesis gas immediately after leaving the high-temperature reactor (10) is subjected to a shock-like water application until cooling below 100 ° C and is dedusted. 15. The method according to any one of the preceding claims, characterized in that the content of hydrogen and / or the volume flow of the derived synthesis gas is determined after the shock-like cooling and accordingly the content of hydrogen and / or the volume flow of the derived synthesis gas is regulated. 16. Device for stock preparation, conversion and post-treatment of waste of all kinds with several thermal treatment stages, which at least one low-temperature stage (6) with exclusion of oxygen and at least one high-temperature stage (10) with oxygen supply Temperatures above 1000 ° C include, as well as with an outlet for the raw synthesis gas mixture generated in the high temperature stage, wherein all reaction spaces of the treatment stages are firmly connected to each other without locks and in the High-temperature stage (10) devices for feeding oxygen and devices for feeding fuel are provided, as well as with a chamber (14) for rapid cooling of the raw synthesis gas mixture with cooling water, for example by spraying the cooling water into the raw synthesis gas stream, and a settling tank (103) for the cooling water , characterized in that the settling tank (103) is connected to a suction device (111, 121) for the gases emerging from the cooling water. 17. The apparatus according to claim 16, characterized in that the settling tank (103) is connected to a device for compressing (111, 121) of the gases emerging from the cooling water. 18. The apparatus according to claim 16 or 17, characterized in that the suction device (111, 121) has an outlet for the extracted gas emerging from the cooling water, which with the high temperature stage (10), the raw synthesis gas path before (100) and / or after (101) the chamber (14) for rapid cooling and / or is connected to a combustion chamber (131). 19. The device according to one of claims 16 to 18, characterized in that it comprises a device for admixing fuel gas to the extracted gas which has escaped from the cooling water. 20. Device according to one of claims 16 to 19, characterized in that the chamber (14) for cooling the tendon has a water injection device for cold water into the hot stream of the synthesis gas mixture. 21. Device according to one of claims 16 to 20, characterized in that the outlet for the synthesis gas mixture has a throttle device, for example a controllable throttle valve. 22. Device according to one of claims 16 to 21, characterized in that a device for gas purification is arranged upstream or downstream of the outlet for the synthesis gas mixture. 23. Device according to one of claims 16 to 22, characterized in that a device for gas utilization is arranged downstream of the outlet for the synthesis gas mixture. 24. The device according to the preceding claim, characterized in that the device for gas utilization is a gas motor-generator combination, a gas turbine or a steam generator. 25. Device according to one of claims 16 to 24, characterized in that the reaction chamber for the low-temperature stage is a horizontally arranged, externally heated pusher oven with a rectangular cross-section, the ratio of the oven width to the oven height of which is greater than two, the oven length being represented by the relationship L _0f e _n ≥ 5 VFofen is given, with Fofen as the cross-sectional area of the pusher furnace. 26. Device according to one of claims 16 to 25, characterized in that the reaction chamber for the high temperature stage is designed as a vertical shaft furnace (10), in the above its bottom, the reaction chamber for the Low temperature level is coupled without interruption. 27. Use of a method according to one of claims 1 to 15 and / or a device according to one of claims 16 to 26, characterized in that after synthesis gas separation or conditioning hydrogen in hydrogen engines or fuel cells and / or the synthesis gas and / or the gases escaping from the cooling water are used for material and / or thermal use.