RU2415076C2 - Method of producing sulphur dioxide and apparatus for realising said method - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to chemistry and can be used in producing sulphur dioxide. The method of producing sulphur dioxide involves successive burning of sulphur in a swirling gas stream at all steps of the process in a three- or four-cyclone furnace, while feeding an oxidising agent at the first step, as well a process fuel for primary heating of the furnace and molten sulphur. At the second combustion step, solid sulphur is added and temperature of the gas stream over its melting zone is kept at 950 - 1300°C by through counterflow of gaseous combustion products into the first cyclone chamber, thereby burning 50-70% of the total amount of the sulphur to be burnt, and the remaining portion of the molten sulphur with solid impurities from melting solid sulphur comes out of the first cyclone furnace. The process gases formed are output at the end of the process. The furnace has cyclone chambers 1, 2, 3. In the bottom part of the furnace between the first and second cyclone chambers there is an overflow channel 6, and in the top part of the furnace between the second and third cyclone chambers there is a gas overflow channel 7. The cover 8 of the first cyclone chamber is fitted with a nozzle 9 for feeding molten sulphur. The bottom part of the third cyclone chamber is fitted with a connection pipe 13 for outlet of process gases, and the bottom part of the second cyclone chamber is fitted with a loading apparatus 14 with an auger 15.

EFFECT: invention increases output of sulphur dioxide.

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Description

The invention relates to methods and devices for burning contaminated sulfur in cyclone furnaces.

A known method of burning liquid and solid waste, carried out in a cyclone furnace, consisting of interconnected cyclone chamber for burning liquid waste and a chamber for burning solid waste. The liquid waste incineration chamber has at least one additional nozzle for supplying non-combustible liquid waste located in the junction zone of the two chambers (SU 974038, F23C 7/00, published 11.11.1982).

There is also known a method for producing sulfur dioxide, which consists in burning sulfur in a vortex gas stream while applying an oxidizing gas to the liquid sulfur layer (SU 1586995, A1, C01B 17/54, publ. 23.08.1990).

This method is carried out in a device - a cyclone furnace, disclosed in the description of the specified copyright certificate No. 1586995.

The disadvantages of the known methods and devices for their implementation is the complexity of the organization of the process of burning sulfur containing ash components. In addition, the supply of only filtered sulfur to the cyclone furnace leads to significant energy consumption necessary for cleaning the entire sulfur stream burned in the installation.

The objective of the invention is to increase the completeness of burning sulfur while ensuring the simultaneous burning of filtered liquid sulfur and part of the unfiltered molten lump sulfur containing solid-phase mineral impurities, as well as ensuring the conclusion of these impurities from the process.

The task in terms of the method is solved by the fact that sequential three- or four-stage combustion of sulfur in a vortex gas stream is carried out at all stages of the process in a multi-stage cyclone furnace when oxidizing agent is fed to the first stage, process fuel for primary heating of the furnace and filtered sulfur is fed by spraying its melt with the conclusion of process gases at the end of the process, lump sulfur is additionally fed to the second stage of combustion and the temperature of the gas stream is maintained above its melted zone it is in the range of 950–1300 ° С, and the sulfur melt formed in the second stage is directed in countercurrent with the combustion gas products to the first stage of the process, burning 50–70% of the total amount of sulfur burned, with the subsequent withdrawal of the remaining part of the melt from the first stage with solid-phase impurities from melting lump sulfur.

In an embodiment of the invention, lump sulfur is additionally fed into the sulfur melt with solid phase impurities withdrawn from the first stage, and the resulting melt with a temperature of 115-120 ° C. is sent for filtration, followed by spraying to the first sulfur burning stage.

At a gas flow temperature above the melting zone below 950 ° C, the completeness of combustion of liquid sulfur is not ensured.

An increase in the temperature of the gas stream above the melting zone above 1300 ° C requires additional energy costs and leads to the destruction of the furnace due to high temperature stresses.

When burning out lump sulfur from a melt, less than 50% of the total amount of sulfur burned leads to a more complicated furnace design due to an increase in the amount of molten sulfur output, which is unacceptable, and when burning out lump sulfur more than 70% of the total amount of sulfur burned, the cinder is not removed, which will reduce the efficiency of the cyclone furnace.

At a temperature of the sulfur melt below 115 ° C, its fluidity is not ensured, which complicates the supply of sulfur through the nozzle, and at a temperature of the sulfur melt above 120 ° C additional energy costs are required.

The problem in view of the device is solved in that the cyclone furnace for producing sulfur dioxide contains a shell with a closed process volume, in which three or four vertical cylindrical cyclone chambers are connected in series along the flow of the gas stream, tangentially directed by transfer channels, the first of which is equipped a spray nozzle for sulfur melt, nozzles for supplying an oxidizing agent and process fuel and a gas burner for igniting ne chi, and the last of the cyclone chambers is made with a process gas outlet device, an additional loading device for lump sulfur is mounted in the lower part of the second cyclone chamber, while the transfer channel connecting the first and second cyclone chambers is located in their bottom part, with the channel bottom on the same level as the bottom of the cyclone chambers, and the first cyclone chamber in the bottom is equipped with a pipe for outputting the sulfur melt with solid-phase impurities.

In an embodiment of the invention, the cyclone furnace is provided with an additional vessel for melting sulfur, which is connected by means of a filter, a pump and a spray nozzle to the first cyclone chamber, while the additional vessel is connected to the bottom of the first cyclone chamber by a nozzle for discharging sulfur melt with solid phase impurities and is equipped with an additional loading device lumpy sulfur.

In addition, the shell of the cyclone furnace is equipped with means for supplying air to its technological volume, and tangentially directed channels communicating with the technological volume of the shell are made in the walls of the upper part of the first cyclone chamber.

Figure 1 schematically shows a General view of the device - a section along BB in figure 4, figure 2 is a General view of a cyclone furnace, figure 3 is a section along aa in figure 2 and figure 4 - section along BB in figure 2.

The cyclone furnace contains three vertical cylindrical cyclone chambers 1-3, sequentially placed along the gas flow and enclosed in an outer lined shell 4 with a closed process volume 5. In the lower part of the furnace between the first and second cyclone chambers there is a tangentially located transfer channel 6, and in the upper part of the furnace between the second and third cyclone chambers there is a tangentially located gas transfer channel 7. A spray force is installed along the axis of the first cyclone chamber in the cover 8 nka 9 for supplying a molten sulfur. The gas burner device 10 for igniting the furnace, mounted on the upper level of the cyclone furnace, is equipped with nozzles 11 and 12, respectively, for supplying an oxidizing agent and process fuel. The lower part of the third cyclone chamber is equipped with a pipe 13 for discharging process gases, and the lower part of the second cyclone chamber is equipped with an additional loading device 14 with a screw 15 for supplying lump sulfur.

An overflow channel 6 connecting the first and second cyclone chambers is located in their bottom parts 16, and the bottom of the channel 17 is located at the same level with the bottom of the cyclone chambers to ensure the flow of sulfur melt between the chambers in countercurrent with combustion gas products. The conclusion of the sulfur melt with solid phase impurities from the bottom of the first cyclone chamber is carried out through the pipe 18.

The cyclone furnace is provided with an additional sulfur melting tank 19, connected by means of a pump 20, a filter 21 and a spray nozzle 9 to the first cyclone chamber. The tank 19 is connected to the bottom part 16 of the first cyclone chamber by a pipe 18 and is equipped with an additional charging device 22 for lump sulfur.

Tangentially directed channels 23 are made in the walls of the upper part of the first cyclone chamber, communicating with the technological volume of the shell, and in the lower part of the shell 4 of the cyclone furnace there is a pipe 24 for supplying air to its technological volume.

The method according to the invention is as follows.

Example 1

For the initial heating of the furnace to the first stage of the process through the nozzles 11 and 12, respectively, an oxidizing agent in the amount of 8000 nm ³ and process fuel in the amount of 300 nm ³ are supplied. Burning in an oxidizing environment, the fuel creates a short gas flame, while the resulting fuel gases tangentially enter the volume of the cyclone chamber 1, creating a powerful cyclone in it.

After reaching the required operating temperature in the furnace, the supply of fuel gas is stopped and the sulfur melt is injected into the first cyclone chamber by spraying into the swirling air flow along the axis through the nozzle 9 located in the furnace lid 8, 600 kg of filtered sulfur melt are introduced and oxidized to SO ₂ in an amount of 420 nm ³ . In the furnace, the temperature regime is maintained at 1300 ° C by feeding into the furnace volume through tangentially directed channels 23 located in the walls of the upper part of the first cyclone chamber a swirling air flow in an amount of 11400 nm ³ .

At the same time, 1600 kg of lump sulfur with a content of solid phase impurities in the amount of 40 kg is supplied to the lower part of the second cyclone chamber 2 through an additional charging device 14 at the second stage of sulfur burning. Once in the furnace, lump sulfur reaches a vaporization temperature of 444.6 ° C, while 70% of the total amount of sulfur burned, which is 1400 kg, is evaporated from the sulfur melt into the technological volume of the furnace and oxidized to SO ₂ in the amount of 980 nm ³ . The remaining 200 kg of molten sulfur containing solid phase impurities in an amount of 40 kg are transferred from the second cyclone chamber to the first in countercurrent gas flow, after which they are removed from the furnace to an additional sulfur melting tank 19, to which 400 kg of lump sulfur are additionally fed through a charging device 22 where it melts. The resulting melt with a temperature of 120 ° C through the filter 21 is fed by means of a pump 20 to the first cyclone chamber for burning sulfur, thus only 30% (600 kg) of the total amount of sulfur burned is filtered.

The process gas generated in the combustion of sulfur in an amount of 11400 nm ³ with a content of SO _{2 of} 12.2% and O _{2 of} 8.8% is removed from the cyclone furnace at the end of the process through the pipe 13.

Example 2

For the initial heating of the furnace to the first stage of the process through the nozzles 11 and 12, respectively, an oxidizing agent in the amount of 8000 nm ³ and process fuel in the amount of 350 nm ^{3 are} supplied. Burning in an oxidizing environment, the fuel creates a short gas flame, while the resulting fuel gases tangentially enter the volume of the cyclone chamber 1, creating a powerful cyclone in it.

After reaching the required operating temperature in the furnace, the supply of fuel gas is stopped and the sulfur melt is introduced by spraying into the first cyclone chamber into the swirling air flow along the axis through the nozzle 9 located in the furnace lid 8, 500 kg of filtered sulfur melt is introduced and oxidized to SO ₂ in an amount of 350 nm ³ . In the furnace, the temperature regime is maintained at 950 ° C by feeding into the furnace volume through tangentially directed channels 23 located in the walls of the upper part of the first cyclone chamber a swirling air flow in an amount of 8409 nm ³ .

At the same time, 655 kg of lump sulfur with a content of solid-phase impurities in the amount of 16 kg is supplied to the lower part of the second cyclone chamber 2 through an additional charging device 14 to the second stage of sulfur burning. Once in the furnace, lump sulfur reaches a vaporization temperature of 444.6 ° C, while 50% of the total amount of sulfur burned, which is 500 kg, is evaporated from the sulfur melt into the technological volume of the furnace and oxidized to SO ₂ in an amount of 350 nm ³ . The remaining 155 kg of molten sulfur containing solid phase impurities in an amount of 16 kg are transferred in a countercurrent gas stream from the second cyclone chamber to the first cyclone chamber, and then they are removed from the furnace to an additional sulfur melting tank 19, to which 345 kg of lump sulfur is additionally fed through feed device 22, where it melts. The resulting melt with a temperature of 115 ° C through the filter 21 is fed by means of a pump 20 to the first cyclone chamber for burning sulfur, thus only 50% (500 kg) of the total amount of sulfur burned is filtered.

The process gas generated in the combustion of sulfur in an amount of 8409 nm ³ with a content of SO _{2 of} 8.3% and O _{2 of} 12.7% is removed from the cyclone furnace at the end of the process through the pipe 13.

Thus, in the claimed method and device for its implementation, the following positive effects are achieved: simultaneous combustion of the filtered liquid sulfur and part of the unfiltered molten lump sulfur entering the cyclone furnace in two streams, as well as melting lump sulfur containing solid-phase mineral impurities, and the conclusion from furnace of these impurities in the remainder of the lump sulfur melt.

Claims (5)

1. A method of producing sulfur dioxide, characterized in that the sequential three- or four-stage combustion of sulfur in a vortex gas stream is carried out at all stages of the process in a multistage cyclone furnace when an oxidizing agent, a process fuel for primary heating of the furnace and sulfur melt by atomizing it are supplied to the first stage with the conclusion of the process gases at the end of the process, lump sulfur is additionally fed to the second stage of combustion and the temperature of the gas stream above its melting zone is maintained in the range of 950-1300 ° C and the sulfur melt formed in the second stage is directed countercurrent to the gas products of combustion to the first stage of the process, burning out 50-70% of the total amount of sulfur burned, followed by the removal from the first stage of the remaining part of the melt with solid-phase impurities formed from melting of lump sulfur. 2. The method according to claim 1, characterized in that lump sulfur is additionally fed into the sulfur melt with solid phase impurities withdrawn from the first stage, and the resulting melt with a temperature of 115-120 ° C is sent for filtration, followed by spraying to the first sulfur burning stage. 3. Cyclone furnace for producing sulfur dioxide, characterized in that it contains a shell with a closed process volume, in which three or four vertical cylindrical cyclone chambers are connected in series along the gas flow, tangentially directed by transfer channels, the first of which is equipped with a spray nozzle for sulfur melt, nozzles for the supply of oxidizing agent and process fuel and a gas burner for igniting the furnace, and the last of the cyclone Amer is made with a process gas outlet device, an additional charging device for lump sulfur is mounted in the lower part of the second cyclone chamber, while the transfer channel connecting the first and second cyclone chambers is located in their bottom part, with the channel bottom located at the same level as the cyclone bottom chambers, and the first cyclone chamber in the bottom is equipped with a nozzle for outputting the sulfur melt with solid-phase impurities. 4. The cyclone furnace according to claim 3, characterized in that it is provided with an additional vessel for melting sulfur, connected by means of a filter, a pump and a spray nozzle to the first cyclone chamber, wherein the additional vessel is connected to the bottom of the first cyclone chamber by a nozzle for discharging sulfur melt with solid-phase impurities and equipped with an additional loading device lump sulfur. 5. The cyclone furnace according to claim 3, characterized in that the shell is provided with means for supplying air to its technological volume, and tangentially directed channels communicating with the technological volume of the shell are made in the walls of the upper part of the first cyclone chamber.

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