LT4394B - Device and process for using raw synthesis gas obtained in high-temperature processing and specific converting procedures - Google Patents

Abstract

Invention describes method of use and device for all kind of domestic or industrial waste composing elements, when waste is turned into gas in high temperature and by synthesis obtained unclean gas is being treated by fractional conversion of all such composing elements as hydrogen, carbon monoxide and dioxide, producing such substances suitable for secondary use as water, heavy metals, sulphur, chorine and sodium.

Description

USE OF HIGH-TEMPERATURE RECYCLING AND FRACTIONAL USE OF SYNTHETIC GASES FOR THE RECONSTITUTION AND EXTRACTION OF CLEAN GAS MATERIALS SPECIFIC TO CERTAIN SUBSTANCES

AND DEVICE

The present invention relates to a process for the recovery of materials from the synthesis of untreated gas and their use in the production of gas for the incineration of municipal or industrial waste, in particular noxious and special wastes of any kind, and for the disposal thereof.

Gasification of waste as a thermal treatment of waste is gaining importance, in particular due to the high potential for destruction of toxic materials. In addition, the resulting synthesis gas can be used as a chemical or heat source, and iron and glass minerals are released, but heavy metals such as chlorine and sulfur remain. These elements, which are the basic chemicals, are either harmful to the biosphere itself (heavy metals) or their reaction products, primarily with water, become a component of acid rain. Therefore, flushing of the synthesis gas is undesirable even with modern machinery. Filters (fabric), adsorption (activated carbon), precipitation reactions and ion exchange are widely used in waste treatment and can therefore also be used for the purification of crude synthesis gas, especially in combinations of these.

Sediment and dust generated by these methods are special wastes that need to be stored and costly. Even though their volume is small compared to the total amount of waste, the storage of gas treatment waste is complicated because the storage of each specific type of waste is a risk for the environment and the used material has to be removed from the farm's metabolism.

The object of the present invention is to provide a process for the recovery of valuable materials from the synthesis of untreated gas by converting the waste into a gas and avoiding storage deposits during such a process. It is a further object of the invention to prevent environmental pollution by sewage. After all, another object of the invention is to provide a device for carrying out the intended method of the invention.

The precondition for the recovery of materials contained in the crude synthesis gas is the gradual conversion of these materials, which are considered to be harmful, to valuable raw materials in separate incandescent wet treatment steps. The recovery of the contents of the materials, in the individual stages of the heated wet treatment, enables the optimum conversion conditions to be adapted to the specific materials contained in the gas. The temperature set in the treatment steps depends on the purpose necessary for the partial separation by the gradual condensation of water vapor in the crude gas synthesis. The constituent materials of the individual conversion steps that need to be converted into valuable starting materials are reconstituted by adding the solutions and condensates of the various conversion steps together and step by step, step by step, by precipitation reactions and ion exchange, restoring the process water required. Cold drying of the synthesized crude gas, which is purified of unwanted materials, removes residual moisture which, together with the reconstituted water used in the process, is again added to separate conversion steps to form a closed loop of water used in the process.

Thus, the fact that the purification of the crude synthesis gas, which not only precipitates the constituents of the synthesis, but also precedes the precipitation to a form which can be used directly after the precipitation, allows for the purification of the synthesis gas The water used in the process is subjected to a combination of gradual precipitation and ion-exchange reactions, providing an easy way to recover valuable materials, since the reactions in the conversion steps and the types of precipitation and ion-exchange reactions can be selected to operate selectively.

The materials present in the crude synthesis gas can be separated, if necessary, and directly, i.e. without conversion, but only if it is in accordance with the spirit of the invention, that is, if the isolated material can be used technically. Therefore, this should be the case where a catalytic, selective precipitation step could be provided along the path of the fusion crude gas stream.

This possibility of precipitation occurs, for example, in the case of sulfur treatment, which can be elementally precipitated using the catalytic action of the so-called "Sulferox" method. Sulfur then becomes a fully usable material.

In the state of the art, purification of crude synthesis gas usually involves rapid cooling as soon as the gas leaves the high-temperature reactor in order to terminate the re-synthesis of organic harmful substances ("de-novo"). Synthetic crude gas passes through a water shower in this case. According to the invention, this water shower, so-called "Quench", can be used as a first conversion step to act as a water jet at pH <5, i.e. in an acidic environment. Chlorine hydrogen and heavy metals are then converted into the reconstituted chlorides. After the acid synthesis shower, the crude gas enters the neutralizing wet treatment step, which operates in an alkaline environment. As this step passes, the gas is optimally heated for subsequent specific conversion steps. This offers several advantages:

- the water vapor contained in the crude synthesis gas is condensed in the shower and does not interfere with subsequent conversion processes;

- the water collected from the spray stage is returned to the neutralization stage and can be reused after neutralization;

- The synthesis crude gas enters the following processing steps at optimum temperature and improves and accelerates the reaction.

The great advantage is that the gas thus heated continues to pass several conversion stages which are arranged in one common reservoir distributed in accordance with the intended steps. Such distribution is described in EP 95106932.7 patent "Combined detergent". Inside this combined converter, a single step of dust removal can be provided using a device with a higher viscosity than water, e.g. glycerin. The dust remover is cleaned of dust in a closed loop and regenerated, the dust is directed to the high temperature reactor and there it is again involved in the gasification reaction. At this point, the recovery of the harmful substances in the path of the fusion crude gas stream and its transfer to the waters of the various conversion stages is completed. Synthesis gas purified from unwanted mixtures may be subjected to additional refrigeration, if necessary, to remove residual moisture, and the resulting dry gas may be heated and passed through an activated carbon filter for thermal or chemical use. Cold drying can be performed in a separate treatment step. Integrating this step into a combined converter has the advantage. Gas heating from this stage and from the sprinkler shower can be combined as needed and used for heating the conversion stages and gas.

The solutions and condensates from the conversion and refrigeration stages used for the recovery of valuable materials can be stored in dispersed form as needed, and further added and processed together. Initially, iron and heavy metals such as lead and zinc are precipitated in one step by hydroxide deposition. The precipitated iron compounds from the first stage of the hydroxide precipitation are re-directed to the high temperature reactor and removed therefrom in the form of molten and metallic granules suitable for further use. The precipitated downstream blends contain other heavy metals and can be prepared as concentrates, a feedstock suitable for metallurgy.

The solution from the hydroxide precipitation step consists of alkali metal chlorides. The existing portion of calcium ions is precipitated in the form of calcium carbonate by injection of carbon dioxide and is further directed to a high temperature reactor for melting. Ion exchange can remove small amounts of remaining calcium ions and the alkali metal chloride, a salt that remains untreated. The alkali chloride solution thus purified is concentrated. For this, the solution is treated with reverse osmosis. Ultimately, the evaporator-crystallizer provides the right feedstock, a salt mixture and condensate that can be used as water. The process of the present invention provides for the utilization of all high temperature reactor gases, vapors and dusts, without the formation of waste water.

The device for implementing the method comprises a gas flow path of convertible materials and a high temperature reactor and conversion step feedback device. At the same time, the flow path for the synthesis gas includes, at a minimum, the following processing steps: sudden cooling at pH <5, neutralization at pH> 8, as well as a combined converter and, if necessary, other wet processing steps for converting the content materials to materials that can be reused, the glycerine dust deposition step, the Sulferox step and the freeze-drying step. The combined converter is equipped with a gas heating stage and an activated carbon filter. In this order, the unpurified synthesis gas passes through the gas flow path of the unit and comes in the form of a very cleanly synthesized synthesis gas that can be used in chemistry and / or heat generation. The material recovery pathway serving the conversion of convertible materials comprises at least the following reaction steps: iron hydroxide precipitation, other heavy metal hydroxide precipitation, carbon dioxide and ion exchange calcium, reversible osmosis and crystallization evaporation, all of which are accompanied by the reversible cooling water , neutralization and conversion steps, and then being collected and passed through the first hydroxide precipitation pathway for material recovery. Each of the reaction steps in the recovery path has a discharge unit for materials such as sulfur, heavy metal hydroxides, table salt and gas, as well as return feed units in a high temperature reactor for settling flush. Residual water after material restoration is suitable for any application.

By combining the heat supply stages of the rapid cooling, gas heating, cold drying and conversion stages, the overall efficiency of the unit can be improved, which may include an appropriate heat exchanger and, where appropriate, heat pumps.

The invention will now be described with reference to the accompanying drawings. In this drawing, position 1 denotes a high-temperature reactor which acts as a melting reactor and has inlets 19 and 20 for iron and its alloying metals and inert minerals, as well as a gas outlet 22 for evacuating the crude gas that is injected into the spray shower. shower 2 at pH <5, viz in the acidic environment, and the conversion of the substances contained in the gas, in particular Cl, Pb, Zn and iron, is started. At the same time, a sudden cooling of the crude synthesis gas is carried out to prevent the re-generation of organic harmful substances (dioxin, furan). The synthesis gas is then introduced into a neutralization bath 3, where, at pH> 8, the moisture in the gas is neutralized. The ratio of pH values in the spray shower 2 and in the neutralization bath 3 is selected, continuously measured during the process and adjusted. After the usually necessary reheating of the gas 6, which due to the reactor conditions is required for the next conversion step, the crude gas in the synthesis passes into a combined converter 4 which has either one or more conversion steps such as glycerol flush to remove the precipitation and cold drying step. Through the outlet 16 sulfur, now ready for use, is derived from the Sulferox stage, regardless of the normal mode conversion stages (including wet). The glycerol flush step comprises a discharge device 8 for removing the deposited dust, which, together with the dust which may contain the adsorbed harmful substances, is directed to the reactor 1 for high temperature treatment. After the freeze-drying, the synthesis gas is heated (reheat 6 ”) and passed through an activated carbon filter through the unit outlet 18 • already cleaned very clean. In one embodiment of the invention, it is proposed to place the activated carbon filter in replaceable cartridges through which gas passes. This can facilitate the introduction and removal of activated carbon into the reactor. The cartridges can then be reused. The heat sources and leaks (6 ', 6', 6, freeze drying) in the gas flow path described may be thermally blocked using suitable elements such as heat exchangers and pumps as shown in position 16 and directional arrows. The water from the spray shower 2, the neutralization 3 and the combined converter 4 is collected and discharged through the pipe system 7 to the first stage of hydroxide deposition 9.

In this step, the precipitated iron hydroxide is transferred to the high temperature reactor 1 by means of device 15 and melted there. The collected water then passes to the second hydroxide precipitation step 10 where the lead and zinc hydroxides are precipitated and removed in the form of a mixture by means of the device 21. This mixture can be used as a feedstock using known melting techniques.

After the second step of hydroxide deposition, the remaining calcium ions bound to CO2 can be precipitated. The water used in the process must, above all,

Ί Sodium and potassium chlorides, which may not be completely purified from calcium. The ion exchange device 11 removes this calcium, and the reverse osmosis step 12 concentrates the alkali metal chlorides, which then crystallize in the form of salts suitable for use in the evaporator 13 and are discharged through the discharge device 17. This purifies the water from the former materials and used in the process. This process does not release effluents.

From the drawing it becomes clear that by using the inventive idea it is possible to convert waste into gas not only by eliminating harmful substances into the environment, but also by utilizing them energetically and by rebuilding the materials contained in the waste, i.e.

without isolating any residues that should be stored or polluting the environment with any sewage.

By utilizing the high-temperature recycling method of the present invention, waste of various nature and composition can be completely transformed into recyclable materials, i.e. in mineral pellets, iron alloys, distilled water, simple sulfur, electrolytic salt mixtures, zinc and lead concentrate.

Claims (14)

1, A process for the use of components of municipal or industrial waste without emitting harmful substances, comprising the synthesis of crude gas 5 high-temperature recycling and fractional conversion to a specific material, characterized in that: - Converts noxious substances in the synthesis crude gas into useful substances in separate, heated, wet treatment steps, assigning temperature steps to each treatment step 10 stepwise condensation of the water vapor in the crude gas synthesis necessary for partial deposition; - batches together solutions and condensates of convertible materials of various conversion steps and precipitates useful materials by use of stepwise precipitation and ion-exchange reactions and isolation reactions, 15 water used in the processes; - freeze-drying the synthesis gas during the conversion of the purified harmful substances and returns the reconstituted water together with condensate from the freeze-drying to separate conversion steps. 20th 2. The method of claim 1, further comprising the step of providing at least one catalytic precipitation step on the path of the fusion crude gas that can act selectively. 3. A method according to claim 1, characterized in that it comprises an injection shower In the form of 25, the quenching step converts the hydrogen chloride and heavy metals to the recovery chlorides at pH <5. 4. A process as claimed in claims 1 and 3, characterized by neutralizing the residual after acidic shower synthesis gas in the wet treatment step. 30 moisture and gives the synthesis gas the optimum temperature for subsequent specific conversion steps. 5. A process according to claims 1-4, characterized in that it utilizes several conversion steps arranged in one common but distributed reservoir and passes the synthesis gas through this approximately constant temperature "combined converter". 6. A process according to claims 1-5, characterized in that the particle deposition step inside the "combined converter" uses a separate, closed system of additives and reintroduces the reaction particles deposited in the reactor resulting from the gasification of the waste. 7. A process according to claims 1-5, characterized in that it regenerates iron and other heavy metals, such as, for example, from the solutions and condensates collected in the refrigeration and conversion steps by at least two-step hydroxide deposition. zinc and lead, reintroduce the precipitated iron compounds into the high temperature reactor, melt and remove them in the form of metal granules, and prepare other heavy metal hydroxides as concentrates suitable for use in smelting furnaces or directly as feedstock. 8. A process according to claims 1-7, wherein the alkali chloride chloride solution from the hydroxide precipitation step is purified from the calcium ions in an ion exchange device. 9. A process as claimed in claims 1-8, which concentrates the purified alkali chloride chloride solution in a ion exchange device by reverse osmosis and crystallizes in an evaporator to give a suitable feedstock, salt mixture and water condensate to be used again in the process. 10. A process as claimed in claims 1-9, wherein the process of recovering heat in the quench step utilizes this heat for heating the synthesis gas and the "combined converter" and the gas entering the activated carbon filter. 11. The apparatus of claim 1-10, wherein: - a synthesis gas flow path comprising at least a wet treatment step such as a quench step (2) at pH <5 and a neutralization step (3) at pH> 8; - one combined converter (4) comprising at least one of the harmful substances conversion step, the glycerol leaching step, the Sulferox washing step and one integral freeze-drying step; - one gas heater (6 ”) and one activated carbon filter (5); - a material recovery path comprising the step of precipitating hydroxide iron (9), the step of hydroxide precipitation of heavy metals (10), the step of ion exchange for calcium (11), the reverse osmosis step (12) and the crystallization evaporation step (13) contaminated water flows from the quenching - neutralization and conversion stages in order, the reaction steps have discharge devices for water (14), purified gas (18), proper use for salt (17), sulfur (16), heavy metal hydroxides (21), iron ( 19) and minerals (20) as well as reactive devices for returning iron hydroxide (15) and carbon materials (8) to the high temperature reactor (1). 12. A device according to claim 11, characterized in that a gas heater (6 ') is provided in the gas flow path between the neutralization (3) and the combined converter (4). 13. Apparatus according to claim 11 or 12, characterized in that the rapid cooling step (2) comprises a heat regenerator (6) partially integrating gas heaters (6 ') and (6') and cold drying. 14. A device according to claims 11-13, characterized in that it comprises a sequentially arranged loading device, a gas heating channel and a high temperature reactor, the latter having one molten material outlet and one synthesis gas outlet located behind the gas purifier.