Method of treatment of solid residues obtained from the combustion of sulfur-containing fuel, and a device for its implementation


F23C11/02 -

 

(57) Abstract:

The invention relates to the combustion of sulfur-containing fuels, such as, for example, some types of coal, or petroleum residues, particularly in boilers with circulating fluidized bed (fluidized) layer, under pressure or at atmospheric pressure. The technical result from the use of the invention is to reduce the carbon dioxide released during the calcination of limestone. This result is achieved by the method of treatment of solid residues obtained from the combustion of sulfur-containing fuel in the device containing the boiler fluidized bed, means for crushing the fuel, means for crushing limestone, the installation for the production of sulfuric acid, means for reactivation solids and means for directing reactivated solids partially in the furnace and partly in cement plant. 2 C. and 10 C.p. f-crystals, 5 Il.

The invention relates to the combustion of sulfur-containing fuels, such as, for example, some types of coal, or petroleum residues, particularly in boilers with circulating fluidized bed (fluidized) layer, under pressure or at atmospheric pressure.

Good WPI is that of burning coal, having a high sulfur content, and lime CaO, coming from limestone, which was previously introduced into the working space of the furnace. The solid residues obtained from this type of combustion is a mixture of coal ash, lime CaO, which has not reacted, and calcium sulfate CaSO4formed by the reaction of lime with sulfur dioxide. To find the application of this firm remains difficult, in particular, they are difficult to use in the manufacture of cement, because the high content of calcium sulfate limits the number of these residues, which can be introduced into the cement without degradation of cement. In addition, the amount of lime introduced into the furnace exceeds the number required to provide the stoichiometric reaction. Therefore, this technology produces more solids than the well-known technology scrubber cleaning of the gas stream.

It is known that solids circulating fluidized bed furnace must be crushed to the controlled grain size, through which is regulated by the heat exchange between the particles and the wall of the furnace. In particular, this means that you want to process only a very small or fine residues (fly ash),, origaudio the bottom of the furnace.

It should also be noted that alternative technologies of energy production through coal gasification have specific processing of the synthesized gas, allowing extraction of sulfur-containing hydrogen (hydrogen sulfide) H2S by rinsing gas scrubbers and process in order to obtain products that can be recycled, for example, elemental sulfur or sulfuric acid.

A method of processing solid residues resulting from the combustion of sulfur-containing fuel in the furnace of a boiler having a circulating fluidized bed, including the introduction of limestone into the furnace in order to make possible the absorption of the obtained sulfur dioxide in the form of calcium sulfate CaSO4(SU 1168101 A, 15.07.85, 6 c).

From the above information it is also known a device for heat treatment that contains a boiler having a circulating fluidized bed and a host of sulfur-containing fuel and limestone.

The present invention is a method and device in which the General or total supply of limestone injected into the furnace corresponds to the ratio, essentially with the giving of the amount of carbon dioxide CO2released during the calcination of limestone, as well as a method and device by which you can easily handle the remnants of burning in order to produce useful by-products, and, in addition, a method, which can be adjusted automatically.

The problem is solved in that in the method of processing solid residues resulting from the combustion of sulfur-containing fuel in the furnace of a boiler having a circulating fluidized bed, including the introduction of limestone into the furnace in order to make possible the absorption of the obtained sulfur dioxide in the form of calcium sulfate CaSO4according to the invention prior to introduction into the furnace fuel is crushed to particle size of not less than 100 μm, before introduction into the furnace limestone is crushed to a particle size in the range from 100 to 150 μm with a maximum particle size of 1 mm, at the base of the furnace combustion residues are collected, while these residues include lime and calcium sulfate resulting from the absorption of sulfur dioxide (SO2produced by burning, and the above-mentioned residues are subjected to heat treatment in the reactor, which receive and solid on the basis of lime CaO and gaseous smeshnoy acid, and the solid is quenched with water and then crushed, while these two operations reactivit specific surface area referred to solids, and a portion of this solid reinjection in the boiler furnace in the form of suspension in water, and the remaining fraction of the substances sent for cement plant.

The heat treatment in the reactor provide oxygen-enriched air, and fly ash resulting from combustion in the boiler is injected into the reactor. Heat treatment temperature in the reactor is in the range from 1100 to 1400oC. the Solid obtained in the reactor for heat treatment is directed to a cement plant with a content of calcium sulphate less than 5%. The reactor is loaded based on the measured pressure in the boiler, and reactivated the substance is injected into the boiler on the basis of the measured sulphur dioxide in the exhaust from the boiler gases.

The problem is solved in that the device for thermal treatment that contains a boiler having a circulating fluidized bed, and a host of sulfur-containing fuel and limestone, according to the invention includes a tool for grinding the fuel particle size less than 100 microns prior to introduction EXILIM smaller than 1 mm, before introducing it into the boiler, a reactor for carrying out heat treatment residue from the boiler, the installation for the production of sulfuric acid that receives gases obtained by carrying out the heat treatment in the reactor, said reactor is connected to the means for reactivation of a solid substance obtained by carrying out the heat treatment in the reactor, and this means includes quenching with water and grinding, and means for directing reactivated solids partially in the furnace and partly in cement plant.

The reactor may be a reactor with a vertical downward layer and contain the furnace, continued from bottom shell, the first conduit to feed in the upper part of the furnace to be processed substance from a boiler, and accordingly the second pipelines to supply the fuel and oxygen-enriched air, the shell for the reception of water through the fourth pipe for quenching the gaseous and solid products resulting from combustion, and the shell has a fifth pipeline to remove gases, obtained by carrying out heat treatment, and a mill for grinding solids to be removed through the hole in the TB combustion chamber, the first pipeline for radial flow in the air chamber, a second pipe for axial upward feed into the chamber of the flow of oxygen-enriched air and a third pipe for supplying into the chamber of the fuel, while the first, second and third pipes are located at the base of the combustion chamber, a fourth pipe for feeding into the chamber to be processed solids, combustion chamber extended passing from the bottom of the shell, which has the fifth pipeline for submission to the shell of water for quenching a solid substance obtained by carrying out heat treatment, the combustion chamber has a sixth pipeline to remove gases, obtained by carrying out heat treatment, and the shell has a mill for grinding solids to be removed through the hole in the base of the shell.

The reactor may be a reactor having a movable layer of the melt, and to contain the combustion chamber having an inclined furnace hearth, a first pipe connected to the bottom of the boiler, for submission to one side of the hearth to be processed substances, respectively, the second and third pipelines to supply in the upper part of the chamber oxygen-enriched air and fuel, Thursday is I heat treatment, the second shell, into which flows a semi-solid substance obtained by carrying out heat treatment, and having a fifth pipeline for submission to the shell of water for quenching semi-solid substances, while the second shell has a mill for grinding a substance that is removed from the shell through a pipeline.

In addition, the reactor may be a rotary kiln furnace, and must contain a drum having an inclined axis, a first pipe connected to the bottom of the boiler, for submission to the first end of the drum to be processed substances, respectively, the second and third pipelines, open at the same end of the drum, for supplying oxygen-enriched air and fuel, the fourth pipeline for removal from the combustion gases obtained by carrying out heat treatment, located at the second end of the drum, a second shell, which under the action of gravity is lowered, the solid is obtained by carrying out heat treatment, and having a fifth pipe to supply the water for quenching a solid substance obtained by carrying out heat treatment, and the shell has a mill for grinding solids, which osoba and various equipment, shown with reference to the accompanying drawings, in which:

Fig. 1 is a block diagram showing the various stages of the method according to the invention;

Fig. 2 is a schematic depiction of the first installation for the heat treatment for the implementation of the method;

Fig. 3 is a schematic depiction of a second installation for the heat treatment for the implementation of the method;

Fig. 4 is a schematic depiction of a third installation for the heat treatment for the implementation of the method;

Fig. 5 is a schematic depiction of a fourth variant of an installation for the heat treatment for implementing the method.

In Fig. 1 position 1 labeled mill that receives coal or oil residues 2, which contain sulfur. In the mill injected air 3 in order to transport the crushed product.

In accordance with the hallmark of the invention, the grinding is performed until the particle size less than 100 microns, which makes it possible to introduce ash to be recycled or transformation in the fly ash, which is not captured at the base of the furnace, which makes it possible to separate it from the material-actroban.

The crushed product 4 is introduced into the boiler furnace 5 having a circulating fluidized bed. The boiler also entered the air 6 and limestone 7. The limestone is ground by the grinding device 7B in order to obtain a grain size that is in accordance with the hydrodynamic conditions with a limited content of fine grains. It is preferable that the size of the grains or particles of limestone ranged from 100 to 150 microns with a maximum size of about 1 mm

The flow of gases 71is cooled in the heat exchanger 8, the dust is removed from the gas particulate filter 9 before the gases are released into the atmosphere 10.

The remains of the combustion chamber 12, consisting of lime, calcium sulphate and a small percentage of coal ash collected at the base of the furnace at a temperature close to 850oC, at which it becomes possible the optimum absorption of sulfur dioxide (SO2in the furnace, which acts as an absorber SO2. The remains of 12 sent to a device for heat treatment 14 and loaded with 15 fuel, such as coal and air 16, optionally enriched with oxygen. In a device for heat treatment also comes the dust collected in the dust filter 9, denoted by I CaSO4were digested with obtaining, in particular, lime CaO and sulfur dioxide (SO2. This gas 18, mixed with the flow of gases, including nitrogen (N2carbon dioxide CO2and the excess oxygen is removed and sent to the plant for production of sulphuric acid 20. In testimony entitled "Le Techniques de l Ingenieur (Engineering Techniques) "6095", describes an example installation for the production of sulfuric acid.

The solid resulting from the combustion occurring in the plant for the heat treatment 14, contains lime CaO and a small proportion (less than approximately 5%) ash fuel as a function of fineness.

In an installation for the heat treatment 14 in the lower part of the injected water 22, while the solid ground.

By quenching with water and grinding solids in this way it becomes possible chemical reactivation unrelated lime. After heat treatment the surface of the lime covered with a sintered layer, which prevents any further chemical compound with the external environment. Hardening and grinding new release of the active surface. Part of the resulting reactivated product 24 is sent in the form of a suspension in water and peramiho fuel as already noted above. As a result of these preparations in the residues of combustion from the boiler is not essentially remains unused limestone. We can say that the entire stock of limestone injection into the furnace corresponds to the stoichiometric proportion in the reaction with sulfur dioxide.

Preinjection fraction of solids 24 from the reactor 14 is directed to a cement plant 25. It does not create any problems, because this fraction contains almost no calcium sulfate, having a percentage by weight of less than 5%.

How reinjection into the furnace particulate matter resulting from combustion in the reactor No. 14, operated and regulated as follows:

by measuring the pressure inside the combustion chamber 5 by means of the measuring device 30, when the pressure exceeds a predetermined threshold value, the solid residues are extracted from the furnace and transferred to the installation for the heat treatment 14, this extract performs in Fig. 1 adjustable valve 31;

by measuring the content of sulfur dioxide (SO2in the flow of gases through other measuring device 35, when the measured content reaches a predetermined threshold, reactivated unaka can also be injection through valve 7A.

In Fig. 2 shows an axial section of the first installation option for thermobreak 14 (or reactor) used at the exit of the boiler, for implementing the method according to the invention.

The reactor 14 is a reactor that has dragged in a downward direction vertical layer.

The reactor has an upper furnace 40A made of refractory material and continued down jacket 40B, which may be made of metal.

In the combustion chamber receives air, optionally enriched with oxygen, and fuel (e.g. coal in powdered form) through the respective inlet pipes 41 and 42.

To be processed substance 12 is removed and the base 5A of the boiler 5, falls under gravity down into the tube 43 that is open in the upper part of the furnace, the valve 5B gives the possibility to stop the flow of matter 12. It should be noted that in the boiler fluidized bed becomes possible to maintain and preserve at the base of the large mass of residue burning (stock), so that the installation for the heat treatment is heat treatment residues, could evenly be downloaded from this buffer mass.

The combustion in the furnace 40A is a torch 45.

After washing in water, the gases are removed through line 47 to the installation for the production of sulfuric acid.

The solid obtained by the heat treatment in the furnace 40A, quenched with water and ground in a mill or crusher 48 for its reactivation and then removed so that part of it can be reinjection in the boiler, and the remaining part can be used at a cement plant.

In Fig. 3 shows another variant of the reactor 14, which is a reactor having a fluidized bed, in which glomerida solid particles.

The reactor comprises a combustion chamber 50A, extended from its bottom shell 50B.

As mentioned above, in the reactor flows to be processed, the product 12 through conduit 34 connected to the bottom of the boiler 5.

At the base of the combustion chamber provided by the inlet nozzle for oxygen-enriched air 51 and 52 and the inlet fuel pipe 53 to the inlet of the fuel, as coal in powdered form.

Burned by the torch 55. Burning torch is 55. Position 55A denotes pseudo is the eye and reach the part 50B, where they are quenched with water supplied through a water inlet pipe 56. Gases resulting from the heat treatment are removed through pipe 57 in the upper part of the chamber 50A.

The solid is reactivated by water and grinding in the mill 58 is then removed so that part of it can be reinjection in the boiler, and the remaining part can be used at a cement plant.

In the variant shown in Fig. 4, the reactor 14 is a reactor having a movable layer of the melt, and contains the combustion chamber 60A having an inclined furnace hearth 60C, the camera serves to be processed products through a pipe 43 connected to the bottom of the boiler 5 at one edge of the bottom, and oxygen-enriched air and fuel through the pipes 61 and 63, respectively, located in the upper part of the chamber 60A, on the other side of the hearth, burning torch is 65.

Gaseous products resulting from heat treatment, in particular, sulfur dioxide (SO2produced in the upper part of the combustion chamber through the channel 67, so that they can be sent to the plant for production of sulphuric acid.

Semi-solid products obtained in the result is 66, and crushed by the mill 68. Received reactivated solid products are extracted from the sheath 60B, for example, by means of the belt conveyor 69 and then removed so that portions of them may be reinjection in the boiler, and the remaining part can be used at a cement plant.

In the variant shown in Fig. 5, the reactor is a rotary kiln containing inclined cylindrical drum 70A mounted can be rotated around its axis, one end of which through a pipe 43 connected to the base 5A of the boiler 5, proceed processed products and in the same end through the respective pipes 71 and 73 are air and fuel. Burning torch is 75.

Gaseous products resulting from heat treatment, in particular, sulfur dioxide (SO2issued at the opposite end of the drum through the pipe 77 so that they can be sent to the plant for production of sulphuric acid.

The solid products obtained by heat treatment, flow into the shell 70B, where they are quenched with water supplied through the inlet pipe 76, and are crushed by the mill 78. Received reactivated test they can be reactivated in the boiler, and the remaining part can be used at a cement plant.

The invention is not limited to the described in the present description options these options are shown only as examples.

1. Method of treatment of solid residues resulting from the combustion of sulfur-containing fuel in the furnace of a boiler having a circulating fluidized bed, including the introduction of limestone into the furnace in order to make possible the absorption of the obtained sulfur dioxide in the form of calcium sulfate CaSO4, characterized in that before the introduction into the furnace fuel is crushed to particle size less than 100 microns, before introduction into the furnace limestone is crushed to a particle size in the range from 100 to 150 μm with a maximum particle size of 1 mm, at the base of the furnace combustion residues are collected, while these residues include lime and calcium sulfate resulting from the absorption of sulfur dioxide (SO2produced by burning, and the above-mentioned residues are subjected to heat treatment in the reactor, which receive and solid on the basis of lime CaO and gaseous mixture containing, in particular, sulfur dioxide (SO2send the sulfur dioxide in the installation for the production of sulphuric collpased surface mentioned solids, and part of this solid reinjection in the boiler furnace in the form of suspension in water, and the remaining fraction of the substances sent for cement plant.

2. The method according to p. 1, characterized in that the heat treatment in the reactor is realized by means of oxygen-enriched air.

3. The method according to p. 1 or 2, characterized in that the fly ash resulting from combustion in the boiler is injected into the reactor.

4. The method according to any of paragraphs.1 to 3, characterized in that the heat treatment temperature is in the range from 1100 to 1400oC.

5. The method according to any of paragraphs.1 to 4, characterized in that the solid substance obtained in the reactor for heat treatment and sent to a cement plant, contains less than 5% calcium sulphate.

6. The method according to any of paragraphs.1 to 5, characterized in that the reactor (14) is loaded on the basis of measured in the boiler pressure.

7. The method according to any of paragraphs.1 - 6, characterized in that the reactivated substance Inuktitut in the boiler on the basis of the measured sulphur dioxide in the exhaust from the boiler gases.

8. Device for heat treatment, containing the boiler (5), having a circulating fluidized bed, and a host of sulfur-containing Topley is 100 μm before introducing it into the boiler, means (7B) for grinding limestone to the size of the particles being in the range from 100 to 150 microns, with a maximum size of less than 1 mm, before introducing it into the boiler, reactor (14) for carrying out heat treatment residues (12) from the boiler, the installation for the production of sulfuric acid (20) that receives gases (18), obtained by carrying out the heat treatment in the reactor (14), said reactor (14) is connected to means for reactivation solids (24), obtained by carrying out the heat treatment in the reactor (14), and it includes quenching with water and grinding, and means (27) for direction reactivated solids, partially in the furnace (5) and partly in cement plant.

9. Device for heat treatment under item 8, characterized in that the reactor (14) is a reactor with a vertical downward layer and contains a furnace (40A), continued on its bottom shell (40B), the first pipeline(43) for filing in the upper part of these furnaces to be processed substances from the boiler (5), and accordingly the second pipeline (41) and (42) for supplying the fuel and oxygen-enriched air shell for receiving water through the fourth pipe (46) for quenching of kazooba is I remove gases, obtained by carrying out heat treatment, and the mill (48) for grinding solids to be removed through the hole in the base of the shell.

10. Device for heat treatment under item 8, characterized in that the reactor (14) is a vertical reactor with a fluidized bed and comprises a combustion chamber (50A), the first pipeline (51) for radial flow in the air chamber, the second conduit (52) for axial upward feed into the chamber of the flow of oxygen-enriched air and the third pipeline (53) for submission to the chamber of the fuel, while the aforementioned first, second and third pipelines are located at the base of the said combustion chamber, a fourth pipe (43) for submission to the camera to be processed solids (12), said combustion chamber extended passing from its bottom shell (50V), which has a fifth conduit (56) for submission to the shell of water for quenching a solid substance obtained by carrying out heat treatment, the combustion chamber (50) has a sixth conduit (57) to remove gases, obtained by carrying out heat treatment, and the shell (50B) has a mill (58) for grinding solids to be removed through the hole in the base of the m, having a movable layer of the melt, and comprises a combustion chamber (60A) having an inclined furnace hearth (60C), the first pipeline (43) connected to the base (5A) of the boiler (5), for submission to one side of the hearth to be processed substances (12), respectively, the second and third pipes (61, 63) for filing in the upper part of the chamber (60A) oxygen-enriched air and fuel, the fourth pipe (67) for removal from the combustion of gaseous products obtained by carrying out heat treatment, the second shell (60V), which flows semi-solid substance obtained by carrying out heat treatment, and having a fifth conduit (66) for submission to the shell of water for quenching mentioned semi-solid substance, and the second shell (60V) has a mill (68) for crushing the substances that are removed from the said shell (60V) through a pipeline (69).

12. Device for heat treatment under item 8, characterized in that the reactor (14) is a rotary kiln furnace and contains the drum (70) having an inclined axis, a first pipe (43), connected to the base (5A) of the boiler (5), for submission to the first end of the drum to be processed substances (12), respectively, second and third is, the fourth pipe (77) for removal from the combustion gases obtained by carrying out heat treatment, located at the second end of the said drum, a second shell (70 V), which under the action of gravity is lowered, the solid is obtained by carrying out heat treatment, and having a fifth conduit (76) for supplying the water for quenching mentioned solids, obtained by carrying out heat treatment, and the shell (70 V) has a mill (78) for grinding referred to the solids that are removed from the said shell (70 V) through a pipeline (79).

 

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