JPH04507217A - Methods and apparatus for treating materials from which methane and other chemicals harmful to the environment are released - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Methane and other substances harmful to the environment 2 chambers that control the release Disposal of environmentally harmful chemicals related to problems caused by environmental pollution It is extremely important to remove it from objects.

When manure from dairy cows, calves, and pigs is transported, stored, or spread on the ground, and when wastewater sludge is Significant amounts of methane, ammonia and sulfur are produced during transport, storage and processing of sludge. Hydrogen chloride is released. Ammonia and hydrogen sulfide in particular are very harmful to the environment.

Ammonia is chemically and biologically oxidized to nitrite and nitric acid, which are Causes acid rain.

Hydrogen sulfide is a gas that smells like rotten eggs and is highly toxic at high concentrations. Become something. This substance is oxidized to sulfurous acid and sulfuric acid, which are also produced by acid rain. Becomes an ingredient.

Methane will also harm the ozone layer.

Therefore, these environmentally hazardous emissions that are released into the atmosphere on farms are of great importance.

Broadly speaking, the present invention applies to each Regarding the method of processing the material, in this case the material is heated and the gas released is immersed in water. or subjected to a cleaning process with a chemical gas cleaning circulation solution and in the gases released from the cleaning equipment. of methane and the heat generated is used at least partially to heat the starting material. There is.

The excess heat generated during combustion may be used for different heating purposes, for example for central heating. stomach.

The method of the invention can also be successfully used to treat manure and/or excreta. be able to. When using this method on the farm, if desired, At the same time as the indoor air from the stable is removed, the indoor air is also washed in a countercurrent manner. Cleaning may be carried out in the device or in a separate cleaning device. Purification as good as possible Use as cold water as possible, for example, water below 12°C, for washing. is preferable. Under these conditions, as much ammonia and sulfide water as possible can be removed. Elements can be removed from the scrubbed gas countercurrently. Because the water temperature The low temperature causes most of the water vapor in the gas stream to condense. into groundwater as cleaning water Use water from the tank you put it in, as that water is usually at a low temperature (10°C). Can be done. Of course, the tank can also be cooled with tap water.

In the cleaning equipment, the contact between the gas flowing upward and the water flowing downward is improved as much as possible. For this purpose, it is preferred to apply conventional packed bed equipment, such as saddle type equipment.

Furthermore, the gas is passed through a condensation column equipped with a packing device whose particle size decreases upward. It is preferable that the water sprayed thereon be guided in a self-current manner.

The ammonia solution collected at the bottom of the condensation column also contains hydrogen sulfide, which is washed from the gas stream. The hydrogen sulfide is sulfurized by passing the solution through iron hydroxide sludge. May be converted to iron. The formed iron sulfide is then sent to a blast furnace to recover the iron. Can be sold to relationships. If desired, replace the ammonia with ammonium hydroxide. It may be collected in water above the sludge layer as a sludge solution. Circulating the solution through the condenser When used as a ring cleaning liquid, the ammonia content of the solution increases to even 50% You may. The solution in the tank may then be replaced with clean water.

Of course, the method according to the invention can also be applied to fertilizers stored in silos.

Fertilizers treated in this way on farms contain almost no ammonia and hydrogen sulfide. , even if later spread on the ground in the usual way, doing so will result in large amounts that are harmful to the environment. of chemicals are not released into the atmosphere.

If a large amount of excess fertilizer is present, it can be heated and concentrated according to the method of the invention. Excess fertilizer can be burned in a combustion furnace. In that case, NH, H, and S are excluded. The removed methane gas can also be combusted in the same furnace. In that case, environmentally harmful Sulfur oxides and nitrogen oxides are formed. This means that those gases coming from the combustion furnace This is why the gas is passed through a heat exchanger and into a bed of calcium oxide. Sulfur in combustion gas CaO, which reacts with yellow oxides and nitrogen oxides, is calcium sulfate and calcium nitrate. It transforms into a system. Additionally, mineral residues containing phosphates are collected at the bottom of the combustion space. this The residue is phosphoric acid formed by combining oxides of sulfur and nitrogen with CaO. Calcium, nitrogen and phosphorus by mixing with calcium and calcium nitrate Feed with valuable fertilizers containing acid salts.

The present invention can be used, for example, to sell a farm to a farm where the exhaust of the cleaned gas containing methane is This also relates to plants with counter-current cleaning equipment located in the connected to a combustion device for It has a combustion gas outlet connected to a heating tube.

The plant can also be located on a ship that collects and transports fertilizer sludge. Ru.

As a special embodiment of the device according to the invention, the stable space is also provided with a gas supply at the bottom of the cleaning device. The air inside the exhaust building is connected to the air supply and therefore would normally be released into the atmosphere. Ammonia and hydrogen sulfide present in the air are recovered therefrom.

If desired, the ammonia solution produced on the farm by the method and apparatus according to the invention is then transported to a center where a concentrated pure ammonia solution is produced; The solution may be transported to locations where concentrated ammonia solution is required.

The invention also relates to a plant as described above, which plant comprises the method according to the invention. storage silos for manure and/or excrement treated in accordance with; A supply device can supply the material to the combustion device, and the combustion gas from the combustion device can be supplied with the material. Heat exchanger connected to the exhaust, and for oxides of sulfur and nitrogen from the combustion gases a vessel with a bed of calcium oxide connected to a heat exchanger.

The invention will be further explained in connection with the drawings of preferred embodiments of the device according to the invention. Ru.

Regarding Fig. 1, heating pipe 2 is installed in fertilizer storage tank 1 (fertilizer pit or silo). There is. The gases on the fertilizer bits are pumped out by a pump 3 and they are transferred into a cleaning device 4. It will be introduced from the bottom up. The device has several packing units with particle size decreasing upwards. It contains layers of units. A horizontal pattern with openings 6 above these layers Type 5 is placed. Pump 16 supplies water to this pipe, and the water is e.g. For example, it has a temperature of up to 10°C. The cleaning device 4 is equipped with an overflow pipe at the bottom. and through it the ammonia and hydrogen sulfide-containing gas collected at the bottom of the cleaning device 4. An aqueous solution of the iron hydroxide sludge is introduced into the iron hydroxide sludge bed 8 from the bottom. So hydrogen sulfide is sulfurized Converts into iron. The ammonia solution is drained over this bed and stored.

Most of ammonia and hydrogen sulfide are removed, but a considerable amount of methane gas is included. The gas is sent to a combustion device 9 where the methane is combusted. When the furnace starts or turns off, Using the gas burner 10, the temperature is set so that the methane in the gas passing through the furnace ignites and The oxygen in the gas can raise the temperature to the point where it burns. The combustion gas , at least partially to heat the fertilizer in Bit 1 before being released into the atmosphere. used for. This lick sends them through the pipe 20 to the heating pipe 2 of the storage tank l. Ru. If desired, the CO2 present in those gases can be dissolved in calcium hydroxide. The combination may be made by passing the gas stream through the liquid.

In a typical embodiment of the device according to the invention, indoor air is also exhausted through the pipe 12. , which air is then sent into the cleaning device 4 together with the gas stream discharged from the fertilizer pit. .

This indoor air is supplied by a perve located inside the stable, which is controlled by an adjustable suction valve. Stables are provided by adjustable fans 13 through pipes 15 attached to each other along the entire length. It is discharged from the building.

FIG. 2 relates to a modification of the device described above, in which case the pipe 12 is A second cleaning of the indoor air separated from the gas discharged and extracted from the fertilizer storage tank Send to device 4a. In both cleaning devices 4 and 4A, the upwardly moving gas is recirculated. The solution is washed with an ammonia solution and the solution is applied to the ground where the iron hydroxide sludge bed is present. The floor 8 is filled with ground water or water pumped by a pump 16 from a tank 11 located inside. is cooled by tap water, which is sent through pipe 29.

A tube 27 is provided in the furnace 9 of both FIGS. 1 and 2, through which water is passed. can flow for purposes other than heating the starting material, e.g. for central heating within the farm. The excess heat generated can be used to One-way valves 39a and 33a A protective gauze is placed in the furnace to prevent flames from flowing back from the combustion furnace. In Figure 2 The branch pipe 25A of This example illustrates that a portion of the gas may be sent to a gas generator.

A control valve 28 is provided in the pipe 20 to control the amount of heat required in the storage tank 1. It is adjusted. The composition of the gas mixture in the combustion chamber 9 is regulated by a control valve 30. It can be divided into sections.

Fig. 3 shows a further development of the apparatus shown in Figs. 1 and 2, in which excess Contains fertilizers that can be burned.

In this plant, excess fertilizer is placed in a collection container 21. Fertilizer pit 1 (1st This fertilizer treated according to the method of the invention in Figs. It has a moisture content. Two layers are formed in the fertilizer pit 1, and the fertilizer is heated. After the tunic and other gases are drawn off, the top layer has a solids content of about 70% by weight. do. Most of the phosphate in the fertilizer bit ends up in these upper layers.

The lower, more liquid layer has much less phosphate and will eventually dephosphorize it. It is then discharged.

Unless the upper layer, which has a much higher phosphate content, is applied directly to the ground as fertilizer, This is carried into the container 21. The dry fertilizer is transferred from this container to a combustion furnace 9 by a transporter 22. Introduce it inside. The mineral residues of the fertilizer fall as ash through the grate 22 at the bottom of the furnace. do. These ashes consist of phosphates and silicates. By burning the fertilizer in the combustion furnace 9 Sulfur oxides and nitrogen oxides are also produced. very harmful to the environment oxides of sulfur and nitrogen to prevent these oxides from escaping into the atmosphere. The hot combustion gases contained therein are passed through a bed 17 of calcium oxide. This calcium oxide Converts sulfur and nitrogen oxides to calcium phosphate and calcium nitrate. heat cycle A collection device 18 and a dust filter 19 are arranged between the combustion furnace 9 and the calcium oxide bed 17. has been done. In the heat exchanger, the circulating water is heated and the combustion gas from the furnace 9 is cooled. Ru. Dust is removed from the combustion gases in a dust filter 19 below the calcium oxide bed. , after which this gas passes through a bed of calcium oxide 19. floor 1 if you want Calcium oxide in No. 9 can be produced by calcining limestone (CaC○,). I can do it. In that case, for example, calcite particles (only 0 ．． Ca CO*), which contains only 5% water, is combined with the fertilizer to be burned in Category 9. can be introduced into These particles are calcined at high temperatures prevailing in the furnace. Ru. The formed CaO is collected together with the fertilizer mineral components in the hearth bottom. CaO, phosphorus Mixtures of acid salts and silicates to bind sulfur and nitrogen oxides in the combustion gases It can be used for floor I9. This converts CaO into calcium phosphate and calcium nitrate. This results in conversion to um. Phosphate, Vl, acid salt, nitrate, and calcium production The mixture may be used as a fertilizer.

In the plant according to FIG. 3, the water heated in the heat exchanger passes through conduit 20 to the The fertilizer is sent to the heating pipe in Iro 1 (see Figures 1 and 2) and heats the fertilizer inside. However, it may also be used, for example, to heat a central heating device 30 or a boiler 31.

When CH and gas coming from the cleaning tower are also used for the combustion engine 24 of the gas generator, , this CH4 gas supplied through conduit 25 is taken out from the stable and sent to the washing tower. The gas mixture of C H4 + 02 + N2 supplied via conduit 26 metals in the gas generator turbine are corroded by nitrogen oxides in the gas stream. Do not pre-mix to prevent licking.

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Claims (12)

[Claims] 1. How to process materials that release methane and other chemicals that are harmful to the environment. The material is then heated and the released gas is washed with water or a chemical gas cleaning circulation solution. During the cleaning process, methane in the gas emitted from the cleaning equipment is burned, and the heat generated is A processing method characterized in that it is used to at least partially heat the starting material. 2. The starting material contains ammonia and the washing is carried out with circulating ammonia solution. A method according to claim 1, characterized in that: 3. Particularly with the use of fertilizers and/or excreta as starting material(s). 3. The method according to claim 2, wherein: 4. The indoor air extracted from stables where livestock live is treated with water or a circulating ammonia solution. Sometimes the manure and/or excreta are cleaned with gas extracted from the heating space. 4. The method according to claim 3, characterized in that: 5. 3. Process according to claim 2, characterized in that the starting material is wastewater sludge. 6. Characterized by cleaning with a cleaning liquid having a temperature not exceeding 12°C A method according to any one of claims 1 to 5. 7. The hydrogen sulfide present in the ammonia solution obtained during cleaning is removed from the solution by water. Claim 2, characterized in that the iron oxide sludge is removed by passing the solution through it. 7. The method according to any one of . 8. The starting material heated according to the method of claim 1 is also placed in a combustion furnace in which methane is combusted. The combustion gas is then cooled in a heat exchanger and passed through a bed of calcium oxide to produce sulfur. It is characterized by combining yellow and nitrogen oxides and then releasing these gases into the atmosphere. 8. The method according to any one of claims 1 to 7, wherein: 9. Formed by the reaction of sulfur and nitrogen oxides in combustion gases with calcium oxide. Calcium sulfate and calcium nitrate are removed from the phosphate-containing residue discharged from the bottom of the furnace. Characterized by mixing with residue to obtain fertilizer containing calcium, phosphate and nitrogen 9. The method according to claim 8. 10. A plant for carrying out the method according to any one of claims 1 to 9. It has a counter-current scrubber with an outlet for the scrubbed gas containing methane at the top. , its discharge part is connected to a combustion device for burning methane, and the combustion device with an outlet for the combustion gases connected to the heating pipes present in the storage space of the starting material Brandt. 11. The stable is also connected to the gas supply at the bottom of the cleaning device or another cleaning device and 11. A blunt according to claim 10, wherein the exhaust gas from the purification device is fed to a combustion device. 12. For fertilizer and/or excrement treated according to the method of claim 1. , a storage silo capable of supplying these materials to a combustion device by means of a feeding device, said combustion device a heat exchanger connected to the outlet of the combustion gases from the combustion gases, and sulfur oxides from the combustion gases; and a calcium oxide bed connected to a heat exchanger to remove nitrogen oxides. The plant according to claim 10 or 11, characterized by a container for.