CA2359149C - Method of cleaning contaminants from a multi-layered mesh filter - Google Patents
Method of cleaning contaminants from a multi-layered mesh filter Download PDFInfo
- Publication number
- CA2359149C CA2359149C CA 2359149 CA2359149A CA2359149C CA 2359149 C CA2359149 C CA 2359149C CA 2359149 CA2359149 CA 2359149 CA 2359149 A CA2359149 A CA 2359149A CA 2359149 C CA2359149 C CA 2359149C
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- Canada
- Prior art keywords
- filter
- cleaning
- degrees fahrenheit
- contaminants
- temperature
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D41/00—Regeneration of the filtering material or filter elements outside the filter for liquid or gaseous fluids
- B01D41/04—Regeneration of the filtering material or filter elements outside the filter for liquid or gaseous fluids of rigid self-supporting filtering material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B08—CLEANING
- B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
- B08B3/00—Cleaning by methods involving the use or presence of liquid or steam
- B08B3/04—Cleaning involving contact with liquid
- B08B3/10—Cleaning involving contact with liquid with additional treatment of the liquid or of the object being cleaned, e.g. by heat, by electricity or by vibration
- B08B3/12—Cleaning involving contact with liquid with additional treatment of the liquid or of the object being cleaned, e.g. by heat, by electricity or by vibration by sonic or ultrasonic vibrations
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Cleaning By Liquid Or Steam (AREA)
Abstract
A method of cleaning contaminants from a multi-layered mesh filter. A first step involves immersing the filter in a chemical presoak tank containing a chemical cleaning agent effective with the contaminants. The chemical presoak tank is maintained at a temperature of not less than 160 degrees fahrenheit and not more than 180 degrees fahrenheit. The filter is maintained in the presoak tank for a time duration sufficient to soften the contaminants without causing the contaminants to break down into layers of constituent elements, while raising the temperature of the filter in preparation for cleaning. A second step involves immersing the filter in a cleaning tank containing hot water maintained at a temperature of not less than 160 degrees fahrenheit and not more than 180 degrees fahrenheit and subjecting the hot water in the cleaning tank to ultrasonic waves at a frequency of not less than 80 megahertz and not more than 120 megahertz.
Description
TITLE OF THE INVENTION:
Method Of Cleaning Contaminants From A Multi-layered Mesh Filter FIELD OF THE INVENTION
The present invention relates to a method of cleaning contaminants from a mufti-layered mesh filter and, in particular, bitumen.
BACKGROUND OF THE INVENTION
Steel mesh filters are used in the Alberta oil sands to remove contaminants from synthetically produced crude oil.
These steel filters consist of multiple layers of steel mesh.
The mesh can be arranged in various braided wire patterns . Over time these steel mesh filters become clogged with contaminants and must be cleaned. In this application the contaminants are bitumen.
Attempts to clean these filters with steam or high pressure water blasting have proven unsuccessful. The steam and high pressure water cleaned surface layers but was incapable of penetrating to the core of the filter. In addition, the high pressure water tended to translocate the bitumen; it moved the bitumen around the filter without removing it. There were also pressure control problems experienced. If there was insufficient pressure, the high pressure water did not clean effectively. If the pressure was too great, the high pressure water would destroy the filter.
Soaking in chemical degreasers has also proven unsuccessful. Although the chemical degreasers are capable of penetrating the core of the filter, leaving the filter in a bath of chemical degreaser merely resulted in the bitumen breaking down into its constituent layers. Instead of cleaning the filter, soaking in chemical degreasers results in the substitution of a cleaning problem involving bitumen for a cleaning problem involving one or more of the constituents of bitumen. With caustic cleaning agents that need to be neutralized, problems were experienced with removing cleaning agent residues. These cleaning agent residues would eat away at the filters destroying them from the inside.
SUMMARY OF THE INVENTION
What is required is a more effective method of cleaning contaminants from a multi-layered mesh filter.
According to the present invention there is provided a method of cleaning contaminants from a multi-layered mesh filter. A first step involves immersing the filter in a chemical presoak tank containing a chemical cleaning agent effective with the contaminants. The chemical presoak tank is maintained at a temperature of not less than 160 degrees fahrenheit and not more than 180 degrees fahrenheit. The filter is maintained in the presoak tank for a time duration sufficient to soften the contaminants without causing the contaminants to break down into layers of constituent elements, while raising the temperature of the filter in preparation for cleaning. A second step involves immersing the filter in a cleaning tank containing hot wager maintained at a temperature of not less than 160 degrees fahrenheit and not more than 180 degrees fahrenheit and subjecting the hot water in the cleaning tank to ultrasonic waves at a frequency of not less than 80 megahertz and not more than 120 megahertz.
The method, as described above, represents the culmination of great deal of research into what works and what does not work. Ultrasonic cleaning will not be effective, unless the filter is presoaked in a chemical cleaning agent to soften the contaminants. The filter must be at the same temperature as the temperature range at which the ultrasonic cleaning takes place. A further purpose of the presoak is, therefore, to raise the temperate of the filter to at or near the desired temperature range. It was found that the ultrasonic cleaning was not effective at temperatures less than 160 degrees fahrenheit. However, when the temperature exceeded 180 degrees fahrenheit the heat began to become detrimental to the process and, in some instances, damaged the filters. At frequencies of less than 80 megahertz the ultrasonic cleaning wa.s not effective. However, at frequencies in excess of 120 megahertz too much cavitation took place, tending to destroy the amplitude of the waves.
Although beneficial results may be obtained through use of the method, as described above, an even greater improvement in the cleaning was achieved by varying the amplitude of the ultrasonic waves. Ultrasonic cleaning is a product of frequency and amplitude. By varying the amplitude, contaminants that would not release from the filter at one amplitude tended to release at another amplitude.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other features of the invention will become more apparent from the following description in which reference is made to the appended drawings, the drawings are for the purpose of illustration only and are not intended to in any way limit the scope of the invention to the particular embodiment or embodiments shown, wherein:
FIGURE 1 is a side elevation view, in section, illustrating pre-soak step of the method in accordance with the teachings of the present invention.
FIGURE 2 is a side elevation view, in section, illustrating a rinsing step of the method in accordance with the teachings of the present invention.
FIGURE 3 is a side elevation view, in section, illustrating a ultrasonic cleaning step of the method in accordance with the teachings of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The preferred method of cleaning contaminants from a multi-layered mesh filter will now be described with reference to FIGURES 1 through 3. Bitumen will be used as a specific example of a contaminant that can be effectively removed in accordance with the teachings of this method.
Referring to FIGURES 1 through 3, there is provided a method of cleaning bitumen from a multi-layered mesh filter that includes several steps . Referring to FIGURE 1, a pre-soak step involves immersing filter 10 in a chemical presoak tank 12 that, contains a chemical cleaning agent 14 effective with bitumen. Chemical cleaning agent 14 is maintained at a temperature of not less than 160 degrees fahrenheit: and not more than 180 degrees fahrenheit. In the illustrated embodiment, chemical presoak tank 12 is equipped with a heater 16 with a temperature controller 18 for heating chemical cleaning agent 14 to the appropriate temperature, however other means are available for maintaining the temperature of presoak tank 12. Ultrasonic cleaning will not be effective, unless filter 10 is presoaked in chemical cleaning agent 14 to soften the contaminants. Filter 10 is maintained in presoak tank 12 for a time duration sufficient to soften bitumen without causing bitumen to break down into layers of its constituent elements, while raising the temperature of filter 10 in preparation for cleaning. Filter 10 must be at the same temperature as the temperature range at which the ultrasonic cleaning takes place for ultrasonic cleaning to be effective.
A period of approximately 20 minutes of soaking filter 10 in tank 12 is usually sufficient. There are a variety of chemical cleaning agents 14 commercially available which are known to be effective in the removal of bitumen. Chemical cleaning agents 14 will, therefore, not be further described.
Referring to FIGURE 2, a rinsing step involves immersing filter 10 in a cleaning tank 20 containing hot water 22 that is maintained at a temperature of not less than 160 degrees fahrenheit and not more than 180 degrees fahrenheit. In the illustrated embodiment, cleaning tank 20 is equipped with a heater 24 and temperature controller 26 for heating hot water to the appropriate temperature, although other means can be used to maintain the temperature in cleaning tank 20.
Ultrasonic cleaning is not effective at temperatures less than 160 degrees fahrenheit, while temperatures that exceed 180 degrees fahrenheit, become detrimental to the process and, in some instances, can damage filter 10.
Method Of Cleaning Contaminants From A Multi-layered Mesh Filter FIELD OF THE INVENTION
The present invention relates to a method of cleaning contaminants from a mufti-layered mesh filter and, in particular, bitumen.
BACKGROUND OF THE INVENTION
Steel mesh filters are used in the Alberta oil sands to remove contaminants from synthetically produced crude oil.
These steel filters consist of multiple layers of steel mesh.
The mesh can be arranged in various braided wire patterns . Over time these steel mesh filters become clogged with contaminants and must be cleaned. In this application the contaminants are bitumen.
Attempts to clean these filters with steam or high pressure water blasting have proven unsuccessful. The steam and high pressure water cleaned surface layers but was incapable of penetrating to the core of the filter. In addition, the high pressure water tended to translocate the bitumen; it moved the bitumen around the filter without removing it. There were also pressure control problems experienced. If there was insufficient pressure, the high pressure water did not clean effectively. If the pressure was too great, the high pressure water would destroy the filter.
Soaking in chemical degreasers has also proven unsuccessful. Although the chemical degreasers are capable of penetrating the core of the filter, leaving the filter in a bath of chemical degreaser merely resulted in the bitumen breaking down into its constituent layers. Instead of cleaning the filter, soaking in chemical degreasers results in the substitution of a cleaning problem involving bitumen for a cleaning problem involving one or more of the constituents of bitumen. With caustic cleaning agents that need to be neutralized, problems were experienced with removing cleaning agent residues. These cleaning agent residues would eat away at the filters destroying them from the inside.
SUMMARY OF THE INVENTION
What is required is a more effective method of cleaning contaminants from a multi-layered mesh filter.
According to the present invention there is provided a method of cleaning contaminants from a multi-layered mesh filter. A first step involves immersing the filter in a chemical presoak tank containing a chemical cleaning agent effective with the contaminants. The chemical presoak tank is maintained at a temperature of not less than 160 degrees fahrenheit and not more than 180 degrees fahrenheit. The filter is maintained in the presoak tank for a time duration sufficient to soften the contaminants without causing the contaminants to break down into layers of constituent elements, while raising the temperature of the filter in preparation for cleaning. A second step involves immersing the filter in a cleaning tank containing hot wager maintained at a temperature of not less than 160 degrees fahrenheit and not more than 180 degrees fahrenheit and subjecting the hot water in the cleaning tank to ultrasonic waves at a frequency of not less than 80 megahertz and not more than 120 megahertz.
The method, as described above, represents the culmination of great deal of research into what works and what does not work. Ultrasonic cleaning will not be effective, unless the filter is presoaked in a chemical cleaning agent to soften the contaminants. The filter must be at the same temperature as the temperature range at which the ultrasonic cleaning takes place. A further purpose of the presoak is, therefore, to raise the temperate of the filter to at or near the desired temperature range. It was found that the ultrasonic cleaning was not effective at temperatures less than 160 degrees fahrenheit. However, when the temperature exceeded 180 degrees fahrenheit the heat began to become detrimental to the process and, in some instances, damaged the filters. At frequencies of less than 80 megahertz the ultrasonic cleaning wa.s not effective. However, at frequencies in excess of 120 megahertz too much cavitation took place, tending to destroy the amplitude of the waves.
Although beneficial results may be obtained through use of the method, as described above, an even greater improvement in the cleaning was achieved by varying the amplitude of the ultrasonic waves. Ultrasonic cleaning is a product of frequency and amplitude. By varying the amplitude, contaminants that would not release from the filter at one amplitude tended to release at another amplitude.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other features of the invention will become more apparent from the following description in which reference is made to the appended drawings, the drawings are for the purpose of illustration only and are not intended to in any way limit the scope of the invention to the particular embodiment or embodiments shown, wherein:
FIGURE 1 is a side elevation view, in section, illustrating pre-soak step of the method in accordance with the teachings of the present invention.
FIGURE 2 is a side elevation view, in section, illustrating a rinsing step of the method in accordance with the teachings of the present invention.
FIGURE 3 is a side elevation view, in section, illustrating a ultrasonic cleaning step of the method in accordance with the teachings of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The preferred method of cleaning contaminants from a multi-layered mesh filter will now be described with reference to FIGURES 1 through 3. Bitumen will be used as a specific example of a contaminant that can be effectively removed in accordance with the teachings of this method.
Referring to FIGURES 1 through 3, there is provided a method of cleaning bitumen from a multi-layered mesh filter that includes several steps . Referring to FIGURE 1, a pre-soak step involves immersing filter 10 in a chemical presoak tank 12 that, contains a chemical cleaning agent 14 effective with bitumen. Chemical cleaning agent 14 is maintained at a temperature of not less than 160 degrees fahrenheit: and not more than 180 degrees fahrenheit. In the illustrated embodiment, chemical presoak tank 12 is equipped with a heater 16 with a temperature controller 18 for heating chemical cleaning agent 14 to the appropriate temperature, however other means are available for maintaining the temperature of presoak tank 12. Ultrasonic cleaning will not be effective, unless filter 10 is presoaked in chemical cleaning agent 14 to soften the contaminants. Filter 10 is maintained in presoak tank 12 for a time duration sufficient to soften bitumen without causing bitumen to break down into layers of its constituent elements, while raising the temperature of filter 10 in preparation for cleaning. Filter 10 must be at the same temperature as the temperature range at which the ultrasonic cleaning takes place for ultrasonic cleaning to be effective.
A period of approximately 20 minutes of soaking filter 10 in tank 12 is usually sufficient. There are a variety of chemical cleaning agents 14 commercially available which are known to be effective in the removal of bitumen. Chemical cleaning agents 14 will, therefore, not be further described.
Referring to FIGURE 2, a rinsing step involves immersing filter 10 in a cleaning tank 20 containing hot water 22 that is maintained at a temperature of not less than 160 degrees fahrenheit and not more than 180 degrees fahrenheit. In the illustrated embodiment, cleaning tank 20 is equipped with a heater 24 and temperature controller 26 for heating hot water to the appropriate temperature, although other means can be used to maintain the temperature in cleaning tank 20.
Ultrasonic cleaning is not effective at temperatures less than 160 degrees fahrenheit, while temperatures that exceed 180 degrees fahrenheit, become detrimental to the process and, in some instances, can damage filter 10.
5 Referring to FIGURE 3, hot. water 22 in cleaning tank 20 is then subjected to ultrasonic waves 28 of not less than 80 megahertz and not more than 120 megahertz while varying the amplitude of ultrasonic waves 28. At frequencies of less than 80 megahertz, ultrasonic cleaning is not effective and at frequencies in excess of 120 megahertz too much cavitation takes place which tends to destroy the amplitude of ultrasonic waves 28. In the illustrated embodiment, an ultrasonic generator 30 is provided for supplying ultrasonic waves 28.
A controller 32 is provided on ultrasonic generator 30 for varying the amplitude of ultrasonic waves 28. By varying the amplitude, contaminants that would not release from filter 10 at one amplitude tend to release at another amplitude.
Exposure of filter 10 and hot water 22 to ultrasonic waves 28 . for a period of approximately 30 minutes has been found to be sufficient. Care must be taken not to over expose filter 10, as excessive exposure to ultrasonic waves 28 will cause bitumen to breakdown into constituent elements.
A further step includes rinsing filter 10. Rinsing of filter 10 aids in removing bitumen particles that were freed from filter 10 during cleaning. If desired a rinse can also take place between the presoak and the ultrasonic cleaning stages to remove any large bitumen particles that have become sufficient softened during the presoak that they can be readily removed without ultrasonics. If desired, a hot water presoak can be used in combination with the chemical presoak. The hot water presoak enables longer dwell times without the bitumen separating into constituent elements. The method as described above is a more effective method of cleaning contaminants from mesh filter 10.
In this patent document, the word "comprising" is used in its non-limiting sense to mean that items following the word are included, but items not specifically mentioned are not excluded. A reference to an element by the indefinite article "a" does not exclude the possibility that more than one of the element is present, unless the context clearly requires that there be one and only one of the elements.
It will be apparent to one skilled in the art that modifications may be made to the illustrated embodiment without departing from the spirit and scope of the invention as hereinafter defined in the Claims.
A controller 32 is provided on ultrasonic generator 30 for varying the amplitude of ultrasonic waves 28. By varying the amplitude, contaminants that would not release from filter 10 at one amplitude tend to release at another amplitude.
Exposure of filter 10 and hot water 22 to ultrasonic waves 28 . for a period of approximately 30 minutes has been found to be sufficient. Care must be taken not to over expose filter 10, as excessive exposure to ultrasonic waves 28 will cause bitumen to breakdown into constituent elements.
A further step includes rinsing filter 10. Rinsing of filter 10 aids in removing bitumen particles that were freed from filter 10 during cleaning. If desired a rinse can also take place between the presoak and the ultrasonic cleaning stages to remove any large bitumen particles that have become sufficient softened during the presoak that they can be readily removed without ultrasonics. If desired, a hot water presoak can be used in combination with the chemical presoak. The hot water presoak enables longer dwell times without the bitumen separating into constituent elements. The method as described above is a more effective method of cleaning contaminants from mesh filter 10.
In this patent document, the word "comprising" is used in its non-limiting sense to mean that items following the word are included, but items not specifically mentioned are not excluded. A reference to an element by the indefinite article "a" does not exclude the possibility that more than one of the element is present, unless the context clearly requires that there be one and only one of the elements.
It will be apparent to one skilled in the art that modifications may be made to the illustrated embodiment without departing from the spirit and scope of the invention as hereinafter defined in the Claims.
Claims (2)
1. A method of cleaning bitumen from a multi-layered mesh filter, comprising the steps of:
immersing the filter in a chemical presoak tank containing a chemical cleaning agent effective with the bitumen maintained at a temperature of not less than 160 degrees fahrenheit and not more than 180 degrees fahrenheit for a time duration sufficient to soften the bitumen without causing the bitumen to break down into layers of constituent elements, while raising the temperature of the filter in preparation for cleaning; and immersing the filter in a cleaning tank containing hot water maintained at a temperature of not less than 160 degrees fahrenheit and not more than 180 degrees fahrenheit and subjecting the hot water in the cleaning tank to ultrasonic waves of not less than 80 megahertz and not more than 120 megahertz while varying the amplitude of the ultrasonic waves.
immersing the filter in a chemical presoak tank containing a chemical cleaning agent effective with the bitumen maintained at a temperature of not less than 160 degrees fahrenheit and not more than 180 degrees fahrenheit for a time duration sufficient to soften the bitumen without causing the bitumen to break down into layers of constituent elements, while raising the temperature of the filter in preparation for cleaning; and immersing the filter in a cleaning tank containing hot water maintained at a temperature of not less than 160 degrees fahrenheit and not more than 180 degrees fahrenheit and subjecting the hot water in the cleaning tank to ultrasonic waves of not less than 80 megahertz and not more than 120 megahertz while varying the amplitude of the ultrasonic waves.
2. The method as defined in Claim 2, including the further step of rinsing the filter.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2359149 CA2359149C (en) | 2001-10-16 | 2001-10-16 | Method of cleaning contaminants from a multi-layered mesh filter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2359149 CA2359149C (en) | 2001-10-16 | 2001-10-16 | Method of cleaning contaminants from a multi-layered mesh filter |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2359149A1 CA2359149A1 (en) | 2003-04-16 |
| CA2359149C true CA2359149C (en) | 2006-10-31 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2359149 Expired - Fee Related CA2359149C (en) | 2001-10-16 | 2001-10-16 | Method of cleaning contaminants from a multi-layered mesh filter |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2359149C (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103721479A (en) * | 2013-12-05 | 2014-04-16 | 天津昭鑫电材科技有限公司 | Soaking tank of filter screens of filter |
-
2001
- 2001-10-16 CA CA 2359149 patent/CA2359149C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CA2359149A1 (en) | 2003-04-16 |
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| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |
Effective date: 20171016 |