CA2149145C - Filtration of soot/ash water slurries and improved partial oxidation process for hydrocarbon feedstocks - Google Patents
Filtration of soot/ash water slurries and improved partial oxidation process for hydrocarbon feedstocks Download PDFInfo
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- CA2149145C CA2149145C CA002149145A CA2149145A CA2149145C CA 2149145 C CA2149145 C CA 2149145C CA 002149145 A CA002149145 A CA 002149145A CA 2149145 A CA2149145 A CA 2149145A CA 2149145 C CA2149145 C CA 2149145C
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-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
- C10J3/00—Production of combustible gases containing carbon monoxide from solid carbonaceous fuels
- C10J3/72—Other features
- C10J3/82—Gas withdrawal means
- C10J3/84—Gas withdrawal means with means for removing dust or tar from the gas
-
- 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
- C01B3/02—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen
- C01B3/32—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of gaseous or liquid organic compounds with gasifying agents, e.g. water, carbon dioxide, air
- C01B3/34—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of gaseous or liquid organic compounds with gasifying agents, e.g. water, carbon dioxide, air by reaction of hydrocarbons with gasifying agents
- C01B3/36—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of gaseous or liquid organic compounds with gasifying agents, e.g. water, carbon dioxide, air by reaction of hydrocarbons with gasifying agents using oxygen or mixtures containing oxygen as gasifying agents
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
- C10J3/00—Production of combustible gases containing carbon monoxide from solid carbonaceous fuels
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
- C10J2300/00—Details of gasification processes
- C10J2300/09—Details of the feed, e.g. feeding of spent catalyst, inert gas or halogens
- C10J2300/0913—Carbonaceous raw material
- C10J2300/0946—Waste, e.g. MSW, tires, glass, tar sand, peat, paper, lignite, oil shale
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
- C10J2300/00—Details of gasification processes
- C10J2300/09—Details of the feed, e.g. feeding of spent catalyst, inert gas or halogens
- C10J2300/0953—Gasifying agents
- C10J2300/0959—Oxygen
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
- C10J2300/00—Details of gasification processes
- C10J2300/09—Details of the feed, e.g. feeding of spent catalyst, inert gas or halogens
- C10J2300/0953—Gasifying agents
- C10J2300/0973—Water
- C10J2300/0976—Water as steam
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
- C10J2300/00—Details of gasification processes
- C10J2300/16—Integration of gasification processes with another plant or parts within the plant
- C10J2300/169—Integration of gasification processes with another plant or parts within the plant with water treatments
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
- C10J2300/00—Details of gasification processes
- C10J2300/18—Details of the gasification process, e.g. loops, autothermal operation
- C10J2300/1846—Partial oxidation, i.e. injection of air or oxygen only
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
- C10J2300/00—Details of gasification processes
- C10J2300/18—Details of the gasification process, e.g. loops, autothermal operation
- C10J2300/1861—Heat exchange between at least two process streams
- C10J2300/1884—Heat exchange between at least two process streams with one stream being synthesis gas
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/10—Process efficiency
- Y02P20/129—Energy recovery, e.g. by cogeneration, H2recovery or pressure recovery turbines
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/141—Feedstock
- Y02P20/143—Feedstock the feedstock being recycled material, e.g. plastics
Abstract
The present invention relates to an improved partial oxidation, gasification process using low grade hydrocarbon feedstock involving the steps of gasification, waste heat recovery and carbon removal under formation of a soot water slurry containing the unburned carbon and ash. The soot water slurry is filtered to Form a filtercake of carbon and ash, which cake is removed from the process. It is thereby established a direct once-through, partial oxidation process avoiding the recycle of unburned carbon and ash. The method also comprises filtration of the soot-ash slurries containing 0.5-3 % unburned carbon and 0.1-2 % ash having appreciable amounts of Fe, Ni and V. The slurry is cooled to a temperature below 80 °C and filtered while confined between movable closed belts maintaining a constant pressure against the shrinking mass of carbon/ash particles until the moisture content is reduced to below 80 % by weight. Flocculating agents are added to the soot slurry before filtration, one in the form of a cationic and the other in the form of an anionic flocculation agent. A flaky, or granular filtercake suitable for further processing is obtained.
Description
fV'Vs0 94/11085 ~ ~ ~ P~T/1~7093IOU16:~
i Filtration of saot/ash water slurries and improved partial oxidation rocess for h drocarbon feedstocks The invention ralates to the filtration of soot/ash water slurries. Such slurries ,are obtained in a,number of chemical processes such as cheanical gasification processes'using heavy hydrocarbon feedstocks. More specifically the invention concerns an improved partial oxidati~n, gasif ication process where the soot/ash water slurry emerging after the carbon removal step of such process is filtered off and disposed of directly.
Partial oxidation processes for hydrocarbon feedstocks were developed and commercialized during the ~9~0°s. The best known processes, such as the Shell gasification process and the ~'exaco gasification prbces~s, have been utilized in a number of commer-vial plants.
Such gasification processes utilizing hydrocarbon fe~dstock normally comprise three principal steps:
~, ' ~asification, in which the feedstock is convericed into raw synthesis gds in the presence o~ oxygen and steam.
i Waste heat reccwery in which high pressure steam is generated from the hod gases leaving the reactor, and Carbon remo~aal , in which residual carbon contained in the reactor outlet gas is,r~moved in, a multistep water wash.
PCT/N093/OU16~
WO 94/110~~
i Filtration of saot/ash water slurries and improved partial oxidation rocess for h drocarbon feedstocks The invention ralates to the filtration of soot/ash water slurries. Such slurries ,are obtained in a,number of chemical processes such as cheanical gasification processes'using heavy hydrocarbon feedstocks. More specifically the invention concerns an improved partial oxidati~n, gasif ication process where the soot/ash water slurry emerging after the carbon removal step of such process is filtered off and disposed of directly.
Partial oxidation processes for hydrocarbon feedstocks were developed and commercialized during the ~9~0°s. The best known processes, such as the Shell gasification process and the ~'exaco gasification prbces~s, have been utilized in a number of commer-vial plants.
Such gasification processes utilizing hydrocarbon fe~dstock normally comprise three principal steps:
~, ' ~asification, in which the feedstock is convericed into raw synthesis gds in the presence o~ oxygen and steam.
i Waste heat reccwery in which high pressure steam is generated from the hod gases leaving the reactor, and Carbon remo~aal , in which residual carbon contained in the reactor outlet gas is,r~moved in, a multistep water wash.
PCT/N093/OU16~
WO 94/110~~
Hereby the unburned carbon from the gasifier will be made into a , carbon slurry, an aqueous suspension containing soot and a significant amount of ash, depending on the feedstock, which has to be further processed and recycled.
Thus a serious drawback of such processes is that a certain percentage of the feedstock is not gasified and remains in the form of soot mixed with appreciable amounts of ash from the heavy hydrocarbon feedstock.
Traditianally the soot recovery is handled by two alternative routes:
1. The carbon is recovered by means of pelletising, where a distillate or a residual fuel oil is used to form agglomerates with the carbon particles. The pellets can easily be separated from the water and are recycled to the react~r and/or burned in a carbon oil furnace.
2. alternatively the carbon slurry is contacted with naphta in an extractor to form naphta soot agglomerates. The agglomerates are subsequently decanted or sieved-off and converted into a pumpable mixture together with the feedstock and recycled to the reactor.
However, as th'e soot is heavily contaminated with ash the disposal of the soot/ash mixtures has gradually become the most serious problems for such gasification processes.
The possibility to separate the soot/ash mixture by filtration and to dispose of it directly is considered as an attractive solution, but has not been applied on a large scale.
Thus a serious drawback of such processes is that a certain percentage of the feedstock is not gasified and remains in the form of soot mixed with appreciable amounts of ash from the heavy hydrocarbon feedstock.
Traditianally the soot recovery is handled by two alternative routes:
1. The carbon is recovered by means of pelletising, where a distillate or a residual fuel oil is used to form agglomerates with the carbon particles. The pellets can easily be separated from the water and are recycled to the react~r and/or burned in a carbon oil furnace.
2. alternatively the carbon slurry is contacted with naphta in an extractor to form naphta soot agglomerates. The agglomerates are subsequently decanted or sieved-off and converted into a pumpable mixture together with the feedstock and recycled to the reactor.
However, as th'e soot is heavily contaminated with ash the disposal of the soot/ash mixtures has gradually become the most serious problems for such gasification processes.
The possibility to separate the soot/ash mixture by filtration and to dispose of it directly is considered as an attractive solution, but has not been applied on a large scale.
More specifically, filtration has been used to recover soot for special applications, such as adsorbant carbon, conductive carbon and carbon black. However, such applications will not solve the disposal problems in a large gasification plant.
The soot/ash slurry from the carbon separation step will normally contain 0.5-3% unburned carbon and 0.1-2% ash. The ash contains appreciable amounts of Ni, Fe and V. The filtering of such a slurry is extremely difficult. As the water is removed the slurry is gradually turned into a soapy paste which is very difficult to handle by normal filtration means. The final water content of the filtercake will be 85% or higher and the pasty consistency of such a filtercake makes it unsuitable for further handling.
Subsequent combustion will result in excessive caking and the high combustion temperatures needed to burn the soot create severe environment and corrosion problems.
To overcome these handling problems it has been proposed to add other solid matter to the slurry. Thus according to DE-A-4003242 a soot water slurry is mixed with sewage sludge (Klarschlamm), whereafter the excess water more easily can be removed from such mixture. Thereafter the remaining solid sludge can be deposited, but the heavy metals and other contaminations are not taken care of and the disposal problems are not solved.
The invention provides a method for filtration of a soot/ash water slurry resulting in a filtercake suited for subsequent handling and processing.
The invention carries out filtration to obtain a filtercake with significantly reduced water content forming granules or flakes instead of a soapy paste.
The soot/ash slurry from the carbon separation step will normally contain 0.5-3% unburned carbon and 0.1-2% ash. The ash contains appreciable amounts of Ni, Fe and V. The filtering of such a slurry is extremely difficult. As the water is removed the slurry is gradually turned into a soapy paste which is very difficult to handle by normal filtration means. The final water content of the filtercake will be 85% or higher and the pasty consistency of such a filtercake makes it unsuitable for further handling.
Subsequent combustion will result in excessive caking and the high combustion temperatures needed to burn the soot create severe environment and corrosion problems.
To overcome these handling problems it has been proposed to add other solid matter to the slurry. Thus according to DE-A-4003242 a soot water slurry is mixed with sewage sludge (Klarschlamm), whereafter the excess water more easily can be removed from such mixture. Thereafter the remaining solid sludge can be deposited, but the heavy metals and other contaminations are not taken care of and the disposal problems are not solved.
The invention provides a method for filtration of a soot/ash water slurry resulting in a filtercake suited for subsequent handling and processing.
The invention carries out filtration to obtain a filtercake with significantly reduced water content forming granules or flakes instead of a soapy paste.
The invention employs the filtration method to provide an improved partial oxidation gasification process in the form of a once through-continuous process to obtain a filtercake suitable for further processing.
The invention also provides a partial oxidation process with no recirculation of ash and unburned carbon to improve the overall efficiency of the gasification process.
These and other aspects of the invention are obtained by means of a filtration carried out at low temperatures below 80°C while confining the soot water slurry between movable filter belts exerting a constant line pressure until the filtercake contains less than 80% water, preferably less than 75% water and is no longer soapy or pasty but is transferred into flakes or agglomerates which are easily separated and well suited for subsequent transport and handling in a drying and/or combustion process.
To further improve the filtering efficiency the soot slurry is mixed with two different polyelectrolyte flocculation agents; one cationic and the other anionic.
In one aspect, the invention provides a method for treatment of an aqueous soot/ash slurry, comprising 0.5-3% unburned carbon and 0.1-2% ash having appreciable amounts of Fe, Ni and V, said method comprising the steps of: cooling the slurry to a temperature of from 20-60°C; adding flocculants comprising one cationic flocculant and one anionic flocculant to the cooled slurry, wherein the total amount of flocculants is 60-100 ppm; and filtering the resultant slurry until the moisture content of the slurry is reduced to below 80% by weight, to obtain a flaky or granular filtercake.
4a Fig. 1 shows a flow sheet of the filtration process.
Fig. 2 is a graph showing the dry matter content of the filtercake at different soot slurry temperatures.
W(? 94111085 PGTfN~93/0016a ._ ~~.~91~
:Cnitial filtering tests in the laboratory revealed that when the dry matter content of the filtercake was increased to 20% or higher, this resulted in the formation of dry flakes or agg-lommerates suitable for further processing, However, choosing carefully the optimal parameters for conventional filtration, using filter aid and optimizing the speed of the filterpress did riot give a satisfactory result in realistic plant tests. The water content was still well above 85o and the resulting filtercake not suitable for further processing.
A new test series was then initiated, incorporating a cooling unit in front of the filtration section and using two poly-electrolyte flocculation agents, nne negatively and one posi-tively loaded: The soot slurry was cooled from 95-90°G to 60°C, 50°C etc., and the dry matter content of the filtercake was measured.
The results of this test are given in table 1 below .
Slurry Slurry Soot Flocculant locculantFlocculant F Dry matter ~ 2 Total ~C ~ kg/m3 l~h _ _ ___ a~h ~_, ppm__________ ~3~~ ~: p ___ _ _ _ - ~--____ 90 ?1.9 32.6 __ 8.0 4.40 140 3a-40 8. 0 3 x 1~0 90 71.9 28.9 60 8.0 3.43 140 90 ?1.9 26.3 53 . 8.,0 3,.,301.40 , 90 ?.1.9 ~ 25.0 Surprisingly it was found that low emperature increased the efficiency of the filtration as is also illustrated in fig. 2.
A,t slurry temperature > 8p'C it is not possible to obtain a f~.ltercake with a satisfactory consistency as the dry matter content then will be below 20%, even if the other filtration parameters are optimizEd.
V1'O 94/~t i0~5 1PCT/N093/0016~
Utilizing the results for the initial tests a full scale filtration method has been developed and successfully tested.
In the flaw sheet of fig. ~1 is shown a completely integrated gasification process where heavy residue oil is reacted in a conventional gasification unit with soot separation.
According to a preferred embodiment of the invention, and as illustrated in fig. l, the feed 12 is converted in the gasifica-tion unit 13 and the gas containing soot/ash is washed in the soot separation step 1. The crude gas 12 is then subjected to purification. The saot/ash water slurry emerging from the soot separation step 2 is initially passed through a cooler 2 to lower the temperature from approx. 95°C to 20-60°C and fed into a soot slurry holding tank 3. The slurry is then passed through a mixer 4 to administer the flocculation agents from a source 5. Two flocculants were used, one positively charged polyelectrolyte sold under the trade mark Praestol 611BC (cationic) and one negatively charged ~alyelectrolyte sold under the trade mark Praestal 2440 (anionic), both being in the form of a white polyacrylamide granulate: The flocculants were added to the slurry in a mixer tank 4 as 0.1-0.3% solutions in water. The total volume of flocculants added was adjusted to between 50-100 ppm and the ratio of cationic . anionic polyelectrolyte was 1.5:1.
Thereafter the slurry was let into a settling tank 6 where the settled mass was removed at the bottom and excess'water removed ~rom the top and returned through pipe 10 to the soot separation step 1.
An integrated filter unit 7 was installed after the sedimentation or settling unit G. However, the sedimentation step is optional and it is possible to supply the filter unit with slurry from the mixer 4.
b~VO 94/l ~0~5 ~ ~ ~~ ~ ~ ~; ~~ PCT/N09310U16~
_, The slurry was dewatered while confined on the movable filter 7, consisting of a horizontally movable filterband followed by two vertically moving filterbands compressed by means of rollers pressing the filterbands together to exert a constant pressure until the water content of the filtercake was reduced to < 800.
Thereafter the filtercake was released onto a movable conveyor belt, in the form of dry flakes or plates with an average thickness of approx. 2 mm, and fed to a combustion unit 8. The product 9 cr~uld be handled and further processed without any problems. The filtrate was also directly suited for washing of the filtercake which was carried out continuously and the filtrate could be returned to the soot separation step without detrimental effects in the filtration process.
The invention also provides a partial oxidation process with no recirculation of ash and unburned carbon to improve the overall efficiency of the gasification process.
These and other aspects of the invention are obtained by means of a filtration carried out at low temperatures below 80°C while confining the soot water slurry between movable filter belts exerting a constant line pressure until the filtercake contains less than 80% water, preferably less than 75% water and is no longer soapy or pasty but is transferred into flakes or agglomerates which are easily separated and well suited for subsequent transport and handling in a drying and/or combustion process.
To further improve the filtering efficiency the soot slurry is mixed with two different polyelectrolyte flocculation agents; one cationic and the other anionic.
In one aspect, the invention provides a method for treatment of an aqueous soot/ash slurry, comprising 0.5-3% unburned carbon and 0.1-2% ash having appreciable amounts of Fe, Ni and V, said method comprising the steps of: cooling the slurry to a temperature of from 20-60°C; adding flocculants comprising one cationic flocculant and one anionic flocculant to the cooled slurry, wherein the total amount of flocculants is 60-100 ppm; and filtering the resultant slurry until the moisture content of the slurry is reduced to below 80% by weight, to obtain a flaky or granular filtercake.
4a Fig. 1 shows a flow sheet of the filtration process.
Fig. 2 is a graph showing the dry matter content of the filtercake at different soot slurry temperatures.
W(? 94111085 PGTfN~93/0016a ._ ~~.~91~
:Cnitial filtering tests in the laboratory revealed that when the dry matter content of the filtercake was increased to 20% or higher, this resulted in the formation of dry flakes or agg-lommerates suitable for further processing, However, choosing carefully the optimal parameters for conventional filtration, using filter aid and optimizing the speed of the filterpress did riot give a satisfactory result in realistic plant tests. The water content was still well above 85o and the resulting filtercake not suitable for further processing.
A new test series was then initiated, incorporating a cooling unit in front of the filtration section and using two poly-electrolyte flocculation agents, nne negatively and one posi-tively loaded: The soot slurry was cooled from 95-90°G to 60°C, 50°C etc., and the dry matter content of the filtercake was measured.
The results of this test are given in table 1 below .
Slurry Slurry Soot Flocculant locculantFlocculant F Dry matter ~ 2 Total ~C ~ kg/m3 l~h _ _ ___ a~h ~_, ppm__________ ~3~~ ~: p ___ _ _ _ - ~--____ 90 ?1.9 32.6 __ 8.0 4.40 140 3a-40 8. 0 3 x 1~0 90 71.9 28.9 60 8.0 3.43 140 90 ?1.9 26.3 53 . 8.,0 3,.,301.40 , 90 ?.1.9 ~ 25.0 Surprisingly it was found that low emperature increased the efficiency of the filtration as is also illustrated in fig. 2.
A,t slurry temperature > 8p'C it is not possible to obtain a f~.ltercake with a satisfactory consistency as the dry matter content then will be below 20%, even if the other filtration parameters are optimizEd.
V1'O 94/~t i0~5 1PCT/N093/0016~
Utilizing the results for the initial tests a full scale filtration method has been developed and successfully tested.
In the flaw sheet of fig. ~1 is shown a completely integrated gasification process where heavy residue oil is reacted in a conventional gasification unit with soot separation.
According to a preferred embodiment of the invention, and as illustrated in fig. l, the feed 12 is converted in the gasifica-tion unit 13 and the gas containing soot/ash is washed in the soot separation step 1. The crude gas 12 is then subjected to purification. The saot/ash water slurry emerging from the soot separation step 2 is initially passed through a cooler 2 to lower the temperature from approx. 95°C to 20-60°C and fed into a soot slurry holding tank 3. The slurry is then passed through a mixer 4 to administer the flocculation agents from a source 5. Two flocculants were used, one positively charged polyelectrolyte sold under the trade mark Praestol 611BC (cationic) and one negatively charged ~alyelectrolyte sold under the trade mark Praestal 2440 (anionic), both being in the form of a white polyacrylamide granulate: The flocculants were added to the slurry in a mixer tank 4 as 0.1-0.3% solutions in water. The total volume of flocculants added was adjusted to between 50-100 ppm and the ratio of cationic . anionic polyelectrolyte was 1.5:1.
Thereafter the slurry was let into a settling tank 6 where the settled mass was removed at the bottom and excess'water removed ~rom the top and returned through pipe 10 to the soot separation step 1.
An integrated filter unit 7 was installed after the sedimentation or settling unit G. However, the sedimentation step is optional and it is possible to supply the filter unit with slurry from the mixer 4.
b~VO 94/l ~0~5 ~ ~ ~~ ~ ~ ~; ~~ PCT/N09310U16~
_, The slurry was dewatered while confined on the movable filter 7, consisting of a horizontally movable filterband followed by two vertically moving filterbands compressed by means of rollers pressing the filterbands together to exert a constant pressure until the water content of the filtercake was reduced to < 800.
Thereafter the filtercake was released onto a movable conveyor belt, in the form of dry flakes or plates with an average thickness of approx. 2 mm, and fed to a combustion unit 8. The product 9 cr~uld be handled and further processed without any problems. The filtrate was also directly suited for washing of the filtercake which was carried out continuously and the filtrate could be returned to the soot separation step without detrimental effects in the filtration process.
Claims (4)
1. A method for treatment of an aqueous soot/ash slurry, comprising 0.5-3% unburned carbon and 0.1-2% ash having appreciable amounts of Fe, Ni and V, said method comprising the steps of:
cooling the slurry to a temperature of from 20-60°C;
adding flocculants comprising one cationic flocculant and one anionic flocculant to the cooled slurry, wherein the total amount of flocculants is 60-100 ppm; and filtering the resultant slurry until the moisture content of the slurry is reduced to below 80% by weight, to obtain a flaky or granular filtercake.
cooling the slurry to a temperature of from 20-60°C;
adding flocculants comprising one cationic flocculant and one anionic flocculant to the cooled slurry, wherein the total amount of flocculants is 60-100 ppm; and filtering the resultant slurry until the moisture content of the slurry is reduced to below 80% by weight, to obtain a flaky or granular filtercake.
2. The method according to claim 1, wherein the flocculants are added in ratio of cationic: anionic polyelectrolyte of about 1.5:1.
3. The method according to claim 1 or 2, wherein the moisture content of the slurry is reduced to below 75%.
4. The method according to claim l, 2 or 3, wherein the filtering of the slurry is conducted while confining the slurry between movable closed belts which exert a constant pressure against a shrinking mass of carbon/ash particles resulting from filtration of the slurry.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NO924338 | 1992-11-11 | ||
| NO924337A NO176669C (en) | 1992-11-11 | 1992-11-11 | Process for the direct disposal of plastic waste by chemical recycling in a process for partial oxidation of hydrocarbons |
| PCT/NO1993/000165 WO1994011085A1 (en) | 1992-11-11 | 1993-11-09 | Filtration of soot/ash water slurries and improved partial oxidation process for hydrocarbon feedstocks |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2149145A1 CA2149145A1 (en) | 1994-05-26 |
| CA2149145C true CA2149145C (en) | 2004-04-13 |
Family
ID=19895568
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002149145A Expired - Lifetime CA2149145C (en) | 1992-11-11 | 1993-11-09 | Filtration of soot/ash water slurries and improved partial oxidation process for hydrocarbon feedstocks |
Country Status (4)
| Country | Link |
|---|---|
| CN (1) | CN1092097A (en) |
| CA (1) | CA2149145C (en) |
| NO (1) | NO176669C (en) |
| WO (1) | WO1994011465A1 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102008056311A1 (en) * | 2008-11-07 | 2010-05-12 | Apk Aluminium Und Kunststoffe Ag | Process for separating individual valuable substances from mixed, in particular comminuted plastic waste |
| CN113185257A (en) * | 2021-03-31 | 2021-07-30 | 太原理工大学 | Solid waste regeneration foamed ceramic material for heat insulation wall and preparation method thereof |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AT396367B (en) * | 1990-09-05 | 1993-08-25 | Oemv Ag | METHOD FOR CONTINUOUSLY introducing a MIXTURE WITH PLASTICS TO BE GASIFIED AND LIQUID TO GASIFY |
| AT397808B (en) * | 1992-04-22 | 1994-07-25 | Oemv Ag | METHOD FOR PRESSURE GASIFICATION OF ORGANIC SUBSTANCES, e.g. PLASTIC MIXTURES |
-
1992
- 1992-11-11 NO NO924337A patent/NO176669C/en unknown
-
1993
- 1993-11-09 CA CA002149145A patent/CA2149145C/en not_active Expired - Lifetime
- 1993-11-09 WO PCT/NO1993/000164 patent/WO1994011465A1/en active Application Filing
- 1993-11-11 CN CN93121334A patent/CN1092097A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| NO176669C (en) | 1995-05-10 |
| CN1092097A (en) | 1994-09-14 |
| NO924337L (en) | 1994-05-13 |
| NO924337D0 (en) | 1992-11-11 |
| WO1994011465A1 (en) | 1994-05-26 |
| CA2149145A1 (en) | 1994-05-26 |
| NO176669B (en) | 1995-01-30 |
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