CA1292620C - Process and device for the separation of a synthesis gas/fly-ash mixture - Google Patents
Process and device for the separation of a synthesis gas/fly-ash mixtureInfo
- Publication number
- CA1292620C CA1292620C CA000496293A CA496293A CA1292620C CA 1292620 C CA1292620 C CA 1292620C CA 000496293 A CA000496293 A CA 000496293A CA 496293 A CA496293 A CA 496293A CA 1292620 C CA1292620 C CA 1292620C
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- Canada
- Prior art keywords
- fly
- ash
- synthesis gas
- mixture
- line
- Prior art date
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10K—PURIFYING OR MODIFYING THE CHEMICAL COMPOSITION OF COMBUSTIBLE GASES CONTAINING CARBON MONOXIDE
- C10K1/00—Purifying combustible gases containing carbon monoxide
- C10K1/02—Dust removal
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B3/00—Hydrogen; Gaseous mixtures containing hydrogen; Separation of hydrogen from mixtures containing it; Purification of hydrogen
- C01B3/50—Separation of hydrogen or hydrogen containing gases from gaseous mixtures, e.g. purification
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Combustion & Propulsion (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Inorganic Chemistry (AREA)
- Processing Of Solid Wastes (AREA)
- Devices And Processes Conducted In The Presence Of Fluids And Solid Particles (AREA)
- Industrial Gases (AREA)
- Cyclones (AREA)
Abstract
A B S T R A C T
A PROCESS AND DEVICE FOR THE SEPARATION
OF A SYNTHESIS GAS/FLY-ASH MIXTURE
A process for the separation of a synthesis gas/fly-ash mixture. The synthesis gas/fly-ash mixture is contacted with inert gas and subsequently fly-ash and a synthesis gas/inert gas mixture are removed independently of one another.
A device for the separation of a synthesis gas/fly-ash mixture according to the process described above. The device comprises a separator that is provided with a line for the supply of the synthesis gas/fly-ash mixture, a line for the supply of the inert gas, a line for the removal of the inert gas/synthesis gas mixture and a line for the removal of the fly-ash, which lines are provided with line-closing means, with the line for the supply of the inert gas and the line for the removal of the inert gas/synthesis gas mixture being provided with means to prevent or limit the inflow of fly-ash into the lines.
The synthesis gas content can be reduced to less than 0.01 Nl synthesis gas per kilogram fly-ash.
A PROCESS AND DEVICE FOR THE SEPARATION
OF A SYNTHESIS GAS/FLY-ASH MIXTURE
A process for the separation of a synthesis gas/fly-ash mixture. The synthesis gas/fly-ash mixture is contacted with inert gas and subsequently fly-ash and a synthesis gas/inert gas mixture are removed independently of one another.
A device for the separation of a synthesis gas/fly-ash mixture according to the process described above. The device comprises a separator that is provided with a line for the supply of the synthesis gas/fly-ash mixture, a line for the supply of the inert gas, a line for the removal of the inert gas/synthesis gas mixture and a line for the removal of the fly-ash, which lines are provided with line-closing means, with the line for the supply of the inert gas and the line for the removal of the inert gas/synthesis gas mixture being provided with means to prevent or limit the inflow of fly-ash into the lines.
The synthesis gas content can be reduced to less than 0.01 Nl synthesis gas per kilogram fly-ash.
Description
The invention relates to a process and device for the separation of a synthesis gas/fly-ash mixture.
During the production of synthesis gas via the in-complete combustion of coal, fly-ash is often formed as a by-product. Before the synthesis gas obtained can be used to manufacture organic compounds or for other possible applications, said fly-ash must first be separated from the synthesis gas.
Separation of the greater part of the synthesis gas from the fly-ash by means of a cyclone separator, one or more filters or a combination thereof is known. However, it appears that separation in accordance with such methods, is insufficiently complete. There always remains so much synthesis gas, almost completely consisting of CO and H2, in the fly-ash that there is a considerable explosion hazard on account of the presence of H2 in the immediate vicinity of the fly-ash and the health of persons in the immediate vicinity of the fly-ash is jeopardized by the presence of CO. It is therefore important to separate almost all of the synthesis gas from the fly-ash before the fly-ash can come into contact with the atmosphere.
It is therefore an object of the present invention to provide a process for the separation of a synthesis gas/fly-ash mixture wherein the synthesis gas can be separated from the fly-ash to such an extent that fly-ash coming into contact with the atmosphere after such separation presents no (or a diminished) explosion and health hazard on account of the respective presence of H2 and CO. It is another object of the present invention to ;~ ~
12~620 provide a device for carrying the said method.
The invention therefore provides a process for the separation of a synthesis gas/fly-ash mixture, comprising the steps of: - conveying the synthesis gas/fly-ash mixture to be separated by means of a carrier gas to a separator; - contacting the said synthesis gas/fly-ash mixture with an inert gas in said separator; and - subsequently removing an inert gas~synthesis gas mixture through a first line of the separator and fly-ash through a second line of the separator.
The invention further provides a device for the separation of a synthesis gas/fly-ash mixture according to the process, described above, comprising a separator provided with a line for the supply of the synthesis gas/fly-ash mixture, a line for the supply of the inert gas, a line for the remaval of the inert gas/synthesis gas mixture and a line for the removal of the fly-ash, which lines are provided with line-closing means, and the line for the supply of the inert gas and the line for the removal of the inert gas/synthesis gas mixture being provided with means in order to prevent or limit the inflow of fly-ash into the said lines.
Although the problem underlying the invention arose in the production of synthesis gas by way of coal gasification the invention is not restricted thereto and the solution of the problem may find more general use. A synthesis gas/fly-ash mixture, whatever the process in which it occurs, can be separated in accordance with the present process to such a degree that the aim ~B
,, ~
;' lZ92~i20 - 2a - 63293-2603 described above is achieved.
In this context, an inert gas is understood to be a gas or gas mixture that does not enter into any reaction with the constituents occurring in the course of the present process under the conditions under which the present process is applied.
Although the presence of CO and/or H2 in the inert gas does not, in principle, have to be eliminated, it is clear that the separation of a synthesis gas/fly-ash mixture will not be improved by the presence of CO and/or H2 in the inert gas. In an advan-tageous embodiment of the invention, therefore, the inert gas contains no CO or H2. Within the terms of the above definition of an inert gas, any inert gas can, in principle, be used. In another advantageous embodiment of the invention, however, an inert gas is used which - in so far as it remains in the fly-ash - entails no health and explosion hazard, such as N2 and CO2.
The synthesis gas/fly-ash mixture is in still another advantageous embodiment of the invention contacted with the inert gas ~ rri lZ9Z6~20 at a pressure of 0.5-30 bar, and in particular at atmospheric pressure, with the temperature being able to vary within wide limits, for example between 0 and 200 C. In an advantageous embodiment of the invention the temperature is the same as the ambient temperature.
The process in accordance with the invention can be applied in continuous, semi-continuous and discontinuous operation. In another advantageous embodiment of the invention the synthesis gas/fly-ash mixture is continuously contacted with the inert gas and the lQ fly-ash and inert gas/synthesis gas mixture is continuously remcved.
The synthesis gas/fly-ash mixture can sui~ably be contacted with the inert gas in such a way that the fly-ash is contacted as a stationary, moving or fluidized bed with the inert gas. When the synthesis gas/fly-ash mixture is contacted with the inert gas, the fly-ash may be brought into and kept in a fluidized state, in which process the inert gas can very suitably be used as fluidizing medium.
After synthesis gas has been sufficiently removed from the fly-ash, the fly-ash can be further processed, stored, du~ped and/or transported.
The removed inert gas/synthesis gas mixture can be further processed or passed to a flaring installation to burn off the CO
and H2 present.
If large quantities of synthesis gas have to be separated from relatively small quantities of fly-ash, the greater part of the synthesis gas may be separated fro~ the fly-ash in the abcve-stated known manner with a cyclone separator, one or more filters or a combination thereof prior to the application of the process according to the present invention. In this case, the advantage is that the greater part of the synthesis gas is free of admixed inert gas. Moreover, the amount of inert gas required is smaller.
Pre-separation can be conducted at a pres Æ e of 5-40 bar.
l~Z~ZO
The process according to the invention can, in principle, be applied in any separator kncwn frcm prior art for the separation of small dust particles and gases.
A suitable devioe for carrying out the process of the in-vention is a device ccmprising a separator provided with a line forthe supply of the synthesis gas/fly-ash mixture, a line for the supply of the inert gas, a line for the remcval of the inert gas/synthesis gas mLxture and a line for the remcval of the fly-ash; the lines are pr~vid~d with line-closing means, with the line for the supply of the inert gas and the line for the removal of the inert gas/synthesis gas mixture being provided with means to prevent or limit the inflow of fly-ash into the lines. In an advantageous embodiment of the invention the line for the supply of the synthesis gas/fly-ash mixture and the line for the removal of the synthesis gas/inert gas mixture are connected to the separator at a relatively high location and the other two lines at a relatively lcw location. In another advantageous ~mbod}ment of the invention the line for the removal of fly-ash is connected at the bottom and the line for the removal of the inert gas/synthesis gas mixture at the top of the separator. The connection locations of the other two lines are determined within the above-stated order by the dimensions and form of the separator, as well as by the pro-cessing arrangement required.
As already mentioned, the process according to the invention can be applied in cont muous, semi-continuous and discontinuous operation.
With a discontinucus processing arrangement, fly-ash and synthesis gas are introduced into the separator through the supply line, while the other lines are closed. Then, in succession, the line for the supply of fly-ash and synthesis gas is closed, the line for the supply of inert gas is opened, the inert gas is introduced into the separator in order to bring the separator to an elevated pressure (up to 30 bar) and the line for the supply of inert gas is closed again. Then the line for the removal of synthesis gas and inert gas is opened, after some time if desired.
lZ~;~620 BeQ use of the higher pressure in the separator, the synthesis gas/inert gas mixture will leave the separator and is remcved.
Finally, in succession, the line for the removal of the synthesis gas/inert gas moxture is closed, the line for the removal of the fly-ash is opened and the fly-ash is removed. If desired, the fly-ash can be removed with the aid of a carrier gas that is preferably the same as the inert gas, for example N2 or CD2. After the line for the removal of fly-ash is closed and the line for the supply of the fly-ash/synthesis gas mixture is opened, the process according to the invention can be repeated with a new quantity of fly-ash/synthesis gas mixture. It is also possible, should the synthesis gas have been insufficiently separated frGm the fly-ash, to subject fly-ash and residual synthesis gas to the above-described process once or several times again. ~his can be done in two ways. Firstly, fly-ash and residual synthesis gas, instead of being remaved from the separator, can be re-contacted with the inert gas in the same separator. Secondly, fly-ash and residual synthesis gas Q n, after being removed from the separator, be conveyed into one (or more) further separator(s) to be re-subjected to the above-described process. It will usually be sufficient to repeat the described process 10 times; good results may be achieved by repeating the process as few as 3 to 6 times.
With a semi-continuous processing arrangement, the synthesis gastfly-ash mixture is introduced into the separator while the other lines are closed. After the line for the supply of the synthesis gas/fly-ash mixture is closed, the lines for the supply of inert gas and the removal of inert gas and synthesis gas are opened and, continuously, inert gas is passed through the fly-ash and the inert gas/synthesis gas mixture is removed until synthesis 3o gas has been sufficiently separated from the fly-ash. After the open lines have been closed, the fly-ash is removed through the lines prcvided for that purpose, possibly with the aid of the above-mentioned carrier gas.
If the process according to the invention is applied in continuous operation, which, as pointed out, is advantageous, inert lZ9;2~20 gas and the fly-ash/synthesis gas mixture are simultaneously and continuously introduced into the separator via the supply line provided for that purpose and fly-ash, as well as inert gas/-synthesis gas mixture, are continuously removed through the lines provided for that purpose. The rate at which the inert gas is passed through the separator can vary between wide limits, as it depends, inter alia, on the rate at which fly-ash and synthesis gas are introduced into the separator, on the amount of synthesis gas to be separated from the fly-ash and on the dimensions of the 10 separator.
Unlike the discontinuous processing arrangement, with semi-continuous and continuous operation the pressure is kept constant.
When the synthesis gas/fly-ash mixture is contacted with the inert gas, the fly-ash can, as stated above, be contacted as a stationary, mDving or fluidized bed with the inert gas. In an advantageous embodiment of the invention a fluidized bed is used, with the separator being provided with means known from prior art for the fluidization of dust particles and with inert gas being used in order to bring the fly-ash into a fluidized state and keep it in that state.
As stated above, a fly-ash/synthesis gas mixture that contains a relatively large proportion of synthesis gas may be subjected to pre-separation before being contacted with the inert gas. Before saîd pre-separation, the mixture has a different fly-ash/synthesis gas composition than thereafter, as in the course of said pre-separation the greater part of the synthesis gas is separated. For the synthesis gas/fly-ash mixture obtained in the course of pre-separation to be conveyed into the separator, the line for the supply of the synthesis gas/fly-ash mixture that is connected to 3o the separator must be connected to the pre-separation device, i.e.
a cyclone separator, one or more filters or a ccmbination thereof.
Pre-separation may be carried out at a pressure of 5-40 bar.
As the synthesis gas/fly-ash mixture is contacted with the inert ~as at a lower pressure, a reduction of pressure must be effected beforehand. For this purpose, the separator according to the f~O
present invention can be provided with means known per se from prior art to reduce pressure in the separator. In an advantageous manner, such means are arranged in the device between the pre-separation stage and the separator. Means for pres Æ e reduction 5 that can be used are, for example, a separate vessel, known per se, that is suitable for pressure reduction or a long - possibly w~und - small-bore pipe. In an advantageous embodiment of the invention a separate vessel is used. After pressure reduction, the synthesis gas/fly-ash mixture is introduced, for example with the aid of a lQ carrier gas, via the line for the supply of the synthesis gas/-fly-ash mixture into the separator.
It is furthermore advantageous for the device to be provided with a vessel that is suitable for the storage of a fly-ash/-synthesis gas mixture; said vessel is situated bet~een the means for effecting the pressure reduction on the one hand and the cyclone separator, filter(s) or co~bination thereof on the other and is ccnnected to them. As already indicated in the foregoing the process and device according to the present invention are particularly relevant for the separation of fly-ash/synthesis gas mixtures obtained from the coal gasification process.
The present invention will now be described by way of example in more detail with reference to the drawing, in which Fig. 1 represents a block-diagram of a device for the separation of a synthesis gas/fly-ash mixture according to the invention.
Synthesis gas, ~btained from the gasification of coal at a pressure of 5-40 bar, is conveyed through a line 1 together with the fly-ash formed as a by-product into a vessel 2, where the greater part of the synthesis gas is separated in known manner from the fly ash by a cyclone separator, one or more filters or a co~bination thereof, which is(are) schematized by the vessel 2.
The separated synthesis gas is removed through a line 3 for further processing or other purposes. The fly-ash, together with the residual synthesis gas, is introduced through a line 4 into a collector vessel 5. The vessel 2 and the vessel 5 are kept at the same pressure as that at which coal gasification was accomplished.
As soon as a sufficient quantity of the fly-ash/synthesis gas mixture is present in the collector vessel 5, it is introduced through a line 6 into a vessel 7, where the pressure is reduced to atmospheric pressure. Subsequently, the fly-ash/synthesis gas mixture is continuously conveyed together with the carrier gas frQm a line 9 into a separator 10. The separator 10 is provided with means in order to bring the fly-ash into a fluidized state and keep it in that state with the aid of a continuous stream of inert gas fram a line 11. Synthesis gas and inert gas are continuously lQ removed through a line 12 and the fly-ash through a line 13.
The fly-ash hereby obtained can be processed, transported or stored without any explosion or health hazard for man or beast that would be presented by the respecti~e presence of H2 or CO.
After pre-separation the amount of synthesis gas in the synthesis qas/fly-ash mixture is still at least 10 Nl synthesis gas per kilogram fly-ash. By applying the process according to the invention, this can be reduced to less than 0.01 Nl synthesis gas per kilogram fly-ash.
Various modifications of the present invention will keccme apparent to those skilled in the art from the foregoing description and accampanying drawing. Such modificatiQns are intended to fall within the scope of the appended claims.
During the production of synthesis gas via the in-complete combustion of coal, fly-ash is often formed as a by-product. Before the synthesis gas obtained can be used to manufacture organic compounds or for other possible applications, said fly-ash must first be separated from the synthesis gas.
Separation of the greater part of the synthesis gas from the fly-ash by means of a cyclone separator, one or more filters or a combination thereof is known. However, it appears that separation in accordance with such methods, is insufficiently complete. There always remains so much synthesis gas, almost completely consisting of CO and H2, in the fly-ash that there is a considerable explosion hazard on account of the presence of H2 in the immediate vicinity of the fly-ash and the health of persons in the immediate vicinity of the fly-ash is jeopardized by the presence of CO. It is therefore important to separate almost all of the synthesis gas from the fly-ash before the fly-ash can come into contact with the atmosphere.
It is therefore an object of the present invention to provide a process for the separation of a synthesis gas/fly-ash mixture wherein the synthesis gas can be separated from the fly-ash to such an extent that fly-ash coming into contact with the atmosphere after such separation presents no (or a diminished) explosion and health hazard on account of the respective presence of H2 and CO. It is another object of the present invention to ;~ ~
12~620 provide a device for carrying the said method.
The invention therefore provides a process for the separation of a synthesis gas/fly-ash mixture, comprising the steps of: - conveying the synthesis gas/fly-ash mixture to be separated by means of a carrier gas to a separator; - contacting the said synthesis gas/fly-ash mixture with an inert gas in said separator; and - subsequently removing an inert gas~synthesis gas mixture through a first line of the separator and fly-ash through a second line of the separator.
The invention further provides a device for the separation of a synthesis gas/fly-ash mixture according to the process, described above, comprising a separator provided with a line for the supply of the synthesis gas/fly-ash mixture, a line for the supply of the inert gas, a line for the remaval of the inert gas/synthesis gas mixture and a line for the removal of the fly-ash, which lines are provided with line-closing means, and the line for the supply of the inert gas and the line for the removal of the inert gas/synthesis gas mixture being provided with means in order to prevent or limit the inflow of fly-ash into the said lines.
Although the problem underlying the invention arose in the production of synthesis gas by way of coal gasification the invention is not restricted thereto and the solution of the problem may find more general use. A synthesis gas/fly-ash mixture, whatever the process in which it occurs, can be separated in accordance with the present process to such a degree that the aim ~B
,, ~
;' lZ92~i20 - 2a - 63293-2603 described above is achieved.
In this context, an inert gas is understood to be a gas or gas mixture that does not enter into any reaction with the constituents occurring in the course of the present process under the conditions under which the present process is applied.
Although the presence of CO and/or H2 in the inert gas does not, in principle, have to be eliminated, it is clear that the separation of a synthesis gas/fly-ash mixture will not be improved by the presence of CO and/or H2 in the inert gas. In an advan-tageous embodiment of the invention, therefore, the inert gas contains no CO or H2. Within the terms of the above definition of an inert gas, any inert gas can, in principle, be used. In another advantageous embodiment of the invention, however, an inert gas is used which - in so far as it remains in the fly-ash - entails no health and explosion hazard, such as N2 and CO2.
The synthesis gas/fly-ash mixture is in still another advantageous embodiment of the invention contacted with the inert gas ~ rri lZ9Z6~20 at a pressure of 0.5-30 bar, and in particular at atmospheric pressure, with the temperature being able to vary within wide limits, for example between 0 and 200 C. In an advantageous embodiment of the invention the temperature is the same as the ambient temperature.
The process in accordance with the invention can be applied in continuous, semi-continuous and discontinuous operation. In another advantageous embodiment of the invention the synthesis gas/fly-ash mixture is continuously contacted with the inert gas and the lQ fly-ash and inert gas/synthesis gas mixture is continuously remcved.
The synthesis gas/fly-ash mixture can sui~ably be contacted with the inert gas in such a way that the fly-ash is contacted as a stationary, moving or fluidized bed with the inert gas. When the synthesis gas/fly-ash mixture is contacted with the inert gas, the fly-ash may be brought into and kept in a fluidized state, in which process the inert gas can very suitably be used as fluidizing medium.
After synthesis gas has been sufficiently removed from the fly-ash, the fly-ash can be further processed, stored, du~ped and/or transported.
The removed inert gas/synthesis gas mixture can be further processed or passed to a flaring installation to burn off the CO
and H2 present.
If large quantities of synthesis gas have to be separated from relatively small quantities of fly-ash, the greater part of the synthesis gas may be separated fro~ the fly-ash in the abcve-stated known manner with a cyclone separator, one or more filters or a combination thereof prior to the application of the process according to the present invention. In this case, the advantage is that the greater part of the synthesis gas is free of admixed inert gas. Moreover, the amount of inert gas required is smaller.
Pre-separation can be conducted at a pres Æ e of 5-40 bar.
l~Z~ZO
The process according to the invention can, in principle, be applied in any separator kncwn frcm prior art for the separation of small dust particles and gases.
A suitable devioe for carrying out the process of the in-vention is a device ccmprising a separator provided with a line forthe supply of the synthesis gas/fly-ash mixture, a line for the supply of the inert gas, a line for the remcval of the inert gas/synthesis gas mLxture and a line for the remcval of the fly-ash; the lines are pr~vid~d with line-closing means, with the line for the supply of the inert gas and the line for the removal of the inert gas/synthesis gas mixture being provided with means to prevent or limit the inflow of fly-ash into the lines. In an advantageous embodiment of the invention the line for the supply of the synthesis gas/fly-ash mixture and the line for the removal of the synthesis gas/inert gas mixture are connected to the separator at a relatively high location and the other two lines at a relatively lcw location. In another advantageous ~mbod}ment of the invention the line for the removal of fly-ash is connected at the bottom and the line for the removal of the inert gas/synthesis gas mixture at the top of the separator. The connection locations of the other two lines are determined within the above-stated order by the dimensions and form of the separator, as well as by the pro-cessing arrangement required.
As already mentioned, the process according to the invention can be applied in cont muous, semi-continuous and discontinuous operation.
With a discontinucus processing arrangement, fly-ash and synthesis gas are introduced into the separator through the supply line, while the other lines are closed. Then, in succession, the line for the supply of fly-ash and synthesis gas is closed, the line for the supply of inert gas is opened, the inert gas is introduced into the separator in order to bring the separator to an elevated pressure (up to 30 bar) and the line for the supply of inert gas is closed again. Then the line for the removal of synthesis gas and inert gas is opened, after some time if desired.
lZ~;~620 BeQ use of the higher pressure in the separator, the synthesis gas/inert gas mixture will leave the separator and is remcved.
Finally, in succession, the line for the removal of the synthesis gas/inert gas moxture is closed, the line for the removal of the fly-ash is opened and the fly-ash is removed. If desired, the fly-ash can be removed with the aid of a carrier gas that is preferably the same as the inert gas, for example N2 or CD2. After the line for the removal of fly-ash is closed and the line for the supply of the fly-ash/synthesis gas mixture is opened, the process according to the invention can be repeated with a new quantity of fly-ash/synthesis gas mixture. It is also possible, should the synthesis gas have been insufficiently separated frGm the fly-ash, to subject fly-ash and residual synthesis gas to the above-described process once or several times again. ~his can be done in two ways. Firstly, fly-ash and residual synthesis gas, instead of being remaved from the separator, can be re-contacted with the inert gas in the same separator. Secondly, fly-ash and residual synthesis gas Q n, after being removed from the separator, be conveyed into one (or more) further separator(s) to be re-subjected to the above-described process. It will usually be sufficient to repeat the described process 10 times; good results may be achieved by repeating the process as few as 3 to 6 times.
With a semi-continuous processing arrangement, the synthesis gastfly-ash mixture is introduced into the separator while the other lines are closed. After the line for the supply of the synthesis gas/fly-ash mixture is closed, the lines for the supply of inert gas and the removal of inert gas and synthesis gas are opened and, continuously, inert gas is passed through the fly-ash and the inert gas/synthesis gas mixture is removed until synthesis 3o gas has been sufficiently separated from the fly-ash. After the open lines have been closed, the fly-ash is removed through the lines prcvided for that purpose, possibly with the aid of the above-mentioned carrier gas.
If the process according to the invention is applied in continuous operation, which, as pointed out, is advantageous, inert lZ9;2~20 gas and the fly-ash/synthesis gas mixture are simultaneously and continuously introduced into the separator via the supply line provided for that purpose and fly-ash, as well as inert gas/-synthesis gas mixture, are continuously removed through the lines provided for that purpose. The rate at which the inert gas is passed through the separator can vary between wide limits, as it depends, inter alia, on the rate at which fly-ash and synthesis gas are introduced into the separator, on the amount of synthesis gas to be separated from the fly-ash and on the dimensions of the 10 separator.
Unlike the discontinuous processing arrangement, with semi-continuous and continuous operation the pressure is kept constant.
When the synthesis gas/fly-ash mixture is contacted with the inert gas, the fly-ash can, as stated above, be contacted as a stationary, mDving or fluidized bed with the inert gas. In an advantageous embodiment of the invention a fluidized bed is used, with the separator being provided with means known from prior art for the fluidization of dust particles and with inert gas being used in order to bring the fly-ash into a fluidized state and keep it in that state.
As stated above, a fly-ash/synthesis gas mixture that contains a relatively large proportion of synthesis gas may be subjected to pre-separation before being contacted with the inert gas. Before saîd pre-separation, the mixture has a different fly-ash/synthesis gas composition than thereafter, as in the course of said pre-separation the greater part of the synthesis gas is separated. For the synthesis gas/fly-ash mixture obtained in the course of pre-separation to be conveyed into the separator, the line for the supply of the synthesis gas/fly-ash mixture that is connected to 3o the separator must be connected to the pre-separation device, i.e.
a cyclone separator, one or more filters or a ccmbination thereof.
Pre-separation may be carried out at a pressure of 5-40 bar.
As the synthesis gas/fly-ash mixture is contacted with the inert ~as at a lower pressure, a reduction of pressure must be effected beforehand. For this purpose, the separator according to the f~O
present invention can be provided with means known per se from prior art to reduce pressure in the separator. In an advantageous manner, such means are arranged in the device between the pre-separation stage and the separator. Means for pres Æ e reduction 5 that can be used are, for example, a separate vessel, known per se, that is suitable for pressure reduction or a long - possibly w~und - small-bore pipe. In an advantageous embodiment of the invention a separate vessel is used. After pressure reduction, the synthesis gas/fly-ash mixture is introduced, for example with the aid of a lQ carrier gas, via the line for the supply of the synthesis gas/-fly-ash mixture into the separator.
It is furthermore advantageous for the device to be provided with a vessel that is suitable for the storage of a fly-ash/-synthesis gas mixture; said vessel is situated bet~een the means for effecting the pressure reduction on the one hand and the cyclone separator, filter(s) or co~bination thereof on the other and is ccnnected to them. As already indicated in the foregoing the process and device according to the present invention are particularly relevant for the separation of fly-ash/synthesis gas mixtures obtained from the coal gasification process.
The present invention will now be described by way of example in more detail with reference to the drawing, in which Fig. 1 represents a block-diagram of a device for the separation of a synthesis gas/fly-ash mixture according to the invention.
Synthesis gas, ~btained from the gasification of coal at a pressure of 5-40 bar, is conveyed through a line 1 together with the fly-ash formed as a by-product into a vessel 2, where the greater part of the synthesis gas is separated in known manner from the fly ash by a cyclone separator, one or more filters or a co~bination thereof, which is(are) schematized by the vessel 2.
The separated synthesis gas is removed through a line 3 for further processing or other purposes. The fly-ash, together with the residual synthesis gas, is introduced through a line 4 into a collector vessel 5. The vessel 2 and the vessel 5 are kept at the same pressure as that at which coal gasification was accomplished.
As soon as a sufficient quantity of the fly-ash/synthesis gas mixture is present in the collector vessel 5, it is introduced through a line 6 into a vessel 7, where the pressure is reduced to atmospheric pressure. Subsequently, the fly-ash/synthesis gas mixture is continuously conveyed together with the carrier gas frQm a line 9 into a separator 10. The separator 10 is provided with means in order to bring the fly-ash into a fluidized state and keep it in that state with the aid of a continuous stream of inert gas fram a line 11. Synthesis gas and inert gas are continuously lQ removed through a line 12 and the fly-ash through a line 13.
The fly-ash hereby obtained can be processed, transported or stored without any explosion or health hazard for man or beast that would be presented by the respecti~e presence of H2 or CO.
After pre-separation the amount of synthesis gas in the synthesis qas/fly-ash mixture is still at least 10 Nl synthesis gas per kilogram fly-ash. By applying the process according to the invention, this can be reduced to less than 0.01 Nl synthesis gas per kilogram fly-ash.
Various modifications of the present invention will keccme apparent to those skilled in the art from the foregoing description and accampanying drawing. Such modificatiQns are intended to fall within the scope of the appended claims.
Claims (15)
1. A process for the separation of a synthesis gas/fly-ash mixture, comprising the steps of:
- conveying the synthesis gas/fly-ash mixture to be separated by means of a carrier gas to a separator;
- contacting the said synthesis gas/fly-ash mixture with an inert gas in said separator; and - subsequently removing an inert gas/synthesis gas mixture through a first line of the separator and fly-ash through a second line of the separator.
- conveying the synthesis gas/fly-ash mixture to be separated by means of a carrier gas to a separator;
- contacting the said synthesis gas/fly-ash mixture with an inert gas in said separator; and - subsequently removing an inert gas/synthesis gas mixture through a first line of the separator and fly-ash through a second line of the separator.
2. The process as claimed in claim 1, wherein the inert gas is N2 or CO2.
3. The process as claimed in claim 1 wherein the synthesis gas/fly-ash mixture is contacted with the inert gas at a pressure of 0.5-30 bar.
4. The process as claimed in claim 3, wherein the con-tacting is effected at atmospheric pressure.
5. The process as claimed in claim 1, wherein the synthesis gas/fly-ash mixture is continuously contacted with the inert gas and both the fly-ash and the inert gas/synthesis gas mixture are removed continuously.
6. The process as claimed in claim 1, wherein, when the synthesis gas/fly-ash mixture is contacted with the inert gas, the fly-ash is brought into and kept in a fluidized state.
7. The process as claimed in claim 6, wherein the fly-ash is brought into and kept in the fluidized state with the aid of the inert gas.
8. The process as claimed in claim 1, wherein the synthesis gas/fly-ash mixture that is contacted with the inert gas is obtained from a fly-ash/synthesis gas mixture, with a different fly-ash/synthesis gas composition, that has been subjec-ted to separation with the aid of a cyclone separator, one or more filters or a combination thereof, with the greater part of the synthesis gas being separated from the fly-ash.
9. The process as claimed in claim 8, wherein the syn-thesis gas/fly-ash mixture that is contacted with the inert gas has been obtained by subjecting the mixture with the different fly-ash/synthesis gas composition to separation with the aid of a cyclone separator, one or more filters or a combination thereof at a pressure of 5-40 bar.
10. A device for the separation of a synthesis gas/fly-ash mixture as claimed in claim 1, comprising a separator that is equipped with a line for the supply of the synthesis gas/fly-ash mixture, a line for the supply of the inert gas, a line for the removal of the inert gas/synthesis gas mixture and a line for the removal of the fly-ash, which lines are provided with line-closing means, with the line for the supply of inert gas and the line for the removal of the inert gas/synthesis gas mixture being provided with means to prevent or limit the inflow of fly-ash into the lines.
11. The device as claimed in claim 10, wherein the line for the supply of the synthesis gas/fly-ash mixture and the line for the removal of the inert gas/synthesis gas mixture are connected at a relatively high location to the separator and the other two lines are connected at a relatively low location.
12. The device as claimed in claim 10, wherein the separator is provided with means to bring the fly-ash into the fluidized state and to keep it in that state.
13. The device as claimed in claim 10, wherein the line for the supply of the synthesis gas/fly-ash mixture is connected to a cyclone separator, one or more filters or a combination thereof, suitable for separating the greater part of the synthesis gas from a synthesis gas/fly-ash mixture with a different fly-ash/-synthesis gas composition.
14. The device as claimed in claim 13, wherein the device is provided with means that are suitable for effecting a pressure reduction, said means being located between the separator on the one hand and between the cyclone separator, filter(s) or com-bination thereof on the other hand and connected to them.
15. The device as claimed in claim 14, wherein the device is provided with a vessel that is suitable for the storage of a fly-ash/synthesis gas mixture, the said vessel being located between the means for effecting the pressure reduction on the one hand and between the cyclone, filter(s) or combination thereof on the other hand and is connected to them.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE3445986A DE3445986C2 (en) | 1984-12-17 | 1984-12-17 | Method and device for the separation of a synthesis gas-fly ash mixture |
| DEP3445986.3 | 1984-12-17 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1292620C true CA1292620C (en) | 1991-12-03 |
Family
ID=6252995
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000496293A Expired - Fee Related CA1292620C (en) | 1984-12-17 | 1985-11-27 | Process and device for the separation of a synthesis gas/fly-ash mixture |
Country Status (6)
| Country | Link |
|---|---|
| JP (1) | JPH0631349B2 (en) |
| CN (1) | CN1013876B (en) |
| AU (1) | AU577169B2 (en) |
| CA (1) | CA1292620C (en) |
| DE (1) | DE3445986C2 (en) |
| ZA (1) | ZA859558B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103657270B (en) * | 2012-09-19 | 2015-06-10 | 中国石油化工集团公司 | Pressure charging and relieving filtering system and method of high-temperature variable-pressure equipment for solid inlet and outlet materials |
| CN104119960B (en) * | 2014-07-31 | 2016-07-20 | 新奥科技发展有限公司 | A kind of flying dust separation method |
| CN105062573A (en) * | 2015-09-21 | 2015-11-18 | 七台河宝泰隆煤化工股份有限公司 | Centralized dust removal device for cyclone dust removers and waste heat boilers |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| ZA803180B (en) * | 1979-03-01 | 1981-11-25 | Stoic Combustion Ltd | Dust cyclone |
-
1984
- 1984-12-17 DE DE3445986A patent/DE3445986C2/en not_active Expired - Fee Related
-
1985
- 1985-11-27 CA CA000496293A patent/CA1292620C/en not_active Expired - Fee Related
- 1985-12-13 ZA ZA859558A patent/ZA859558B/en unknown
- 1985-12-13 CN CN85109035A patent/CN1013876B/en not_active Expired
- 1985-12-16 AU AU51244/85A patent/AU577169B2/en not_active Ceased
- 1985-12-16 JP JP60281286A patent/JPH0631349B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| ZA859558B (en) | 1986-08-27 |
| DE3445986C2 (en) | 1999-08-12 |
| AU5124485A (en) | 1986-06-26 |
| CN85109035A (en) | 1986-06-10 |
| DE3445986A1 (en) | 1986-06-19 |
| AU577169B2 (en) | 1988-09-15 |
| CN1013876B (en) | 1991-09-11 |
| JPS61145296A (en) | 1986-07-02 |
| JPH0631349B2 (en) | 1994-04-27 |
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