GB2038196A - Filter aid - Google Patents
Filter aid Download PDFInfo
- Publication number
- GB2038196A GB2038196A GB7942913A GB7942913A GB2038196A GB 2038196 A GB2038196 A GB 2038196A GB 7942913 A GB7942913 A GB 7942913A GB 7942913 A GB7942913 A GB 7942913A GB 2038196 A GB2038196 A GB 2038196A
- Authority
- GB
- United Kingdom
- Prior art keywords
- filtration
- filtration medium
- filter
- microns
- slurry
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 238000001914 filtration Methods 0.000 claims abstract description 33
- 239000002002 slurry Substances 0.000 claims abstract description 16
- 238000000034 method Methods 0.000 claims abstract description 11
- 239000002245 particle Substances 0.000 claims abstract description 11
- 235000013311 vegetables Nutrition 0.000 claims abstract description 6
- 239000000428 dust Substances 0.000 claims abstract description 5
- 239000011248 coating agent Substances 0.000 claims description 11
- 238000000576 coating method Methods 0.000 claims description 11
- 239000000725 suspension Substances 0.000 claims description 10
- 239000007788 liquid Substances 0.000 claims description 6
- 239000011236 particulate material Substances 0.000 claims description 5
- 238000000151 deposition Methods 0.000 claims description 4
- 230000001464 adherent effect Effects 0.000 claims description 2
- 230000008021 deposition Effects 0.000 claims description 2
- 239000004744 fabric Substances 0.000 abstract description 9
- 230000000717 retained effect Effects 0.000 description 7
- 239000007787 solid Substances 0.000 description 6
- 239000000843 powder Substances 0.000 description 5
- 238000004519 manufacturing process Methods 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- 240000004808 Saccharomyces cerevisiae Species 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 239000000835 fiber Substances 0.000 description 2
- 230000002093 peripheral effect Effects 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 241000609240 Ambelania acida Species 0.000 description 1
- 239000005909 Kieselgur Substances 0.000 description 1
- 240000000111 Saccharum officinarum Species 0.000 description 1
- 235000007201 Saccharum officinarum Nutrition 0.000 description 1
- 239000005708 Sodium hypochlorite Substances 0.000 description 1
- 229920002472 Starch Polymers 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 239000010905 bagasse Substances 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 229910010293 ceramic material Inorganic materials 0.000 description 1
- 238000005352 clarification Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- SHFGJEQAOUMGJM-UHFFFAOYSA-N dialuminum dipotassium disodium dioxosilane iron(3+) oxocalcium oxomagnesium oxygen(2-) Chemical compound [O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[Na+].[Na+].[Al+3].[Al+3].[K+].[K+].[Fe+3].[Fe+3].O=[Mg].O=[Ca].O=[Si]=O SHFGJEQAOUMGJM-UHFFFAOYSA-N 0.000 description 1
- 239000002657 fibrous material Substances 0.000 description 1
- 239000000706 filtrate Substances 0.000 description 1
- 235000013305 food Nutrition 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000002480 mineral oil Substances 0.000 description 1
- 239000010451 perlite Substances 0.000 description 1
- 235000019362 perlite Nutrition 0.000 description 1
- 239000000049 pigment Substances 0.000 description 1
- SUKJFIGYRHOWBL-UHFFFAOYSA-N sodium hypochlorite Chemical compound [Na+].Cl[O-] SUKJFIGYRHOWBL-UHFFFAOYSA-N 0.000 description 1
- 235000019698 starch Nutrition 0.000 description 1
- 239000008107 starch Substances 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 230000001954 sterilising effect Effects 0.000 description 1
- 239000005418 vegetable material Substances 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D37/00—Processes of filtration
- B01D37/02—Precoating the filter medium; Addition of filter aids to the liquid being filtered
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/22—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising organic material
- B01J20/24—Naturally occurring macromolecular compounds, e.g. humic acids or their derivatives
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Analytical Chemistry (AREA)
- Organic Chemistry (AREA)
- Filtering Materials (AREA)
- Filtration Of Liquid (AREA)
Abstract
In a process for the filtration of industrial slurries, in which a precoat bed consisting of a particulate filter aid is deposited on the filter cloth or gauze before the slurry is applied thereto, the filter aid consists of fibrous vegetable matter composed of particles substantially all of which are smaller than 500 microns in diameter. The preferred fibrous matter is bagacillo dust. The precoat can be used with a rotary vacuum drum filter, or with any type of pressure filter in which the precoat technique is normally employed.
Description
SPECIFICATION
Filtration of slurries
This invention relates to the filtration of slurries which are produced in many industrial processes, including the chemical, food, brewing, man-made fibres, pharmaceutical and effluent treatment industries, and also in refineries of mineral oils and in the production of pigments and dyestuffs.
In a conventional technique, known as the "precoat" technique, for filtering slurries and clarifying filtrates, a coating of a particulate filtration medium is deposited on the surface of the liquid-pervious component of filtration apparatus, through which component filtration is to be effected, for example on the external surface of a filter cloth or gauze constituting the peripheral surface of a rotary vacuum drum.
Such a filtration medium or precoat retains the insoluble matter of the slurry on its surface and the liquid phase passes through it and is clarified, and flows away through the cloth or gauze which is the supporting medium for the precoat. Particulate materials used for this purpose include, for example, diatomaceous earth, kieselguhr, perlite and starch. It is an object of the present invention to provide an improved slurry filtration process in which a particulate filtration medium or precoat is employed, and which is applicable to rotary vacuum drum filters and to other types of filters in which the precoat technique is used, notably pressure filters of various types.
According to the invention, in a process for the filtration of a slurry, which includes the steps of depositing a coating of a particulate filtration medium over a surface of a liquid-pervious filter component, and applying the slurry to the coated surface, the said particulate filtration medium consists of fibrous vegetable matter composed of particles substantially all of which aresmallerthan 500 microns in diameter.
Preferably from 55% to 70% by weight of the said filtration medium consists of particles in the size range between 63 microns and 250 microns, that is to say particles capable of passing a 60 mesh BSS sieve (a sieve having 60 meshes to the linear inch) and retained on a 240 mesh BSS sieve. The preferred fibrous vegetable matter is bagacillo dust, which is derived from bagasse, the sugar cane fibre byproduct of the sugar manufacturing process, but other fibrous vegetable materials in finely divided form are also suitable. Bagacillo dust usually includes particles of larger sizes than the range required for the filtration medium and it is therefore screened to obtain material of the required particle size distribution, if necessary also being ground to reduce the larger particles.
The fibrous vegetable matter filtration medium may be employed with a vacuum drum filter of the type on which a particulate filtration medium is normally used, or with any of the known types of pressure filter in which such a medium is used for clarification purposes.
In use, the powdered fibrous material of the required particle size range is mixed with water or any other desired liquid to form a suspension containing, typically, from 2% to 5% of solid particulate material by weight. To prepare the filter for carrying out the filtration process, this suspension is deposited on the liquid-pervious filter component by means of a suitable applicator, which may be of a standard type employed for the application of conventional filtration media, and during the deposition a pressure differential is maintained through the filter component so that the liquid is withdrawn from the deposited suspension and the residual particulate material is compacted to form an adherent coating on the fiber surface.The coating of powdered fibrous filtration medium so formed may be of any suitable thickness, for example from 1 mm to 100 mm, depending upon the type of filter equipment used and the operating requirement. The slurry to be filtered is then applied to the coated filter in the usual manner, the suspended solids being retained on the coated surface and clear liquid passing through the bed of fibrous vegetable matter. During the filtration process, the retained solids may be removed from the filter either continuously or batchwise, by means of a scraper knife formed of hardend steel or ceramic material, or by a driven fluted roller with suitable cutting edges.
In a specific example of a process in accordance with the invention, for the filtration of a yeast slurry, the particulate filtration medium employed is bagacillo dust which has been ground and screened to give a powder of the following particle size distribution, in percentages by weight:~
> 500 microns (retained on a 30 mesh BSS sieve) 0.05-0.20%
> 250 microns (retained on a 60 mesh BSS sieve) 5-10%
> 125 microns (retained on a 120 mesh BSS sieve) :30-35% > 63 microns (retained on a 240 mesh BSS sieve) :25-35% < 63 microns (passing a 240 mesh BSS sieve) 18-30%
This powder is mixed with water to form a suspension containing from 2% to 5% of bagacillo, by weight.This suspension is applied to the exterior of the peripheral surface, formed of filter cloth, of a rotary vacuum drum, which may be of the form described in Patent Specification No. 1,443,432, the drum being evacuated to draw the water of the suspension through the filter cloth and to compact the bagacillo powder on the cloth as a precoat bed: the bagacillo coating so formed is usually 25 to 100 mm thick.
The yeast slurry is then filtered in the usual manner, and during the filtration the deposited solids are removed continuously from the bagacillo-coated surface of the filter cloth by means of a scraper knife, which is advanced typically from 0.01 to 0.5 mm per revolution of the drum. As a result of this advancement of the scraper, a thin layer of the bagacillo coating is removed with each layer of deposited solids: this is necessary to ensure complete removal of the slurry solids. When most of the bagacillo coating has been removed in this way, the advancing scraper is automatically stopped, to avoid possible mechanical damage to the filter cloth which might occur if the coating were completely removed, and the rotation of the drum and filtering operation are also stopped.
The residual thin layer of bagacillo powder is then removed from the filter cloth and the latter is washed and then re-coated with bagacillo powder in readi nessforthe next filtration cycle.
If the slurry to be filtered is of a type requiring a clean environment, for example for the production of a pure, clean liquid, the powdered fibrous filtration medium can be sterilised by boiling the suspension thereof before it is applied to the filter, or alternatively a sterilising chemical, such as a dilute solution of sodium hypochlorite, can be mixed with the precoat suspension.
Claims (5)
1. A process for the filtration of a slurry, which includes the steps of depositing a coating of a particulate filtration medium over a surface of a liquidpervious filter component, and applying the slurry to the coated surface, wherein the said particulate filtration medium consists of fibrous vegetable matter composed of particles substantially all of which are smaller than 500 microns in diameter.
2. A process according to Claim 1, wherein from 55% to 70% by weight of the said filtration medium consists of particles in the size range between 63 microns and 250 microns.
3. A process according to Claim 1 or 2, wherein the said filtration medium consists of bagacillo dust.
4. A process according to Claim 1, 2 or 3, wherein the coating of said filtration medium is deposited on the said filter component in the form of a suspension of 2% to 5% by weight of the particulate material in a liquid, and during such deposition a pressure differential is maintained through the filter component so that the liquid is withdrawn from the suspension and the residual particulate material is compacted to form an adherent coating on the filter component.
5. A process according to Claim 1, carried out substantially as hereinbefore described in the specific example.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB7942913A GB2038196A (en) | 1978-12-19 | 1979-12-12 | Filter aid |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB7849054 | 1978-12-19 | ||
| GB7942913A GB2038196A (en) | 1978-12-19 | 1979-12-12 | Filter aid |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB2038196A true GB2038196A (en) | 1980-07-23 |
Family
ID=26270015
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB7942913A Withdrawn GB2038196A (en) | 1978-12-19 | 1979-12-12 | Filter aid |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2038196A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2612801A1 (en) * | 1987-03-24 | 1988-09-30 | Louche Yves | Use of micronised and dried plants as adsorbents for organic matter in solution or emulsion in water |
| WO2002036730A3 (en) * | 2000-10-31 | 2002-07-18 | Univ Catholique Louvain | Method for filtration of a liquid, in particular for the filtration of beer, using a filter aid |
| CN115896357A (en) * | 2022-12-14 | 2023-04-04 | 河南豫鑫糖醇有限公司 | Method for purifying xylose solution |
-
1979
- 1979-12-12 GB GB7942913A patent/GB2038196A/en not_active Withdrawn
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2612801A1 (en) * | 1987-03-24 | 1988-09-30 | Louche Yves | Use of micronised and dried plants as adsorbents for organic matter in solution or emulsion in water |
| WO2002036730A3 (en) * | 2000-10-31 | 2002-07-18 | Univ Catholique Louvain | Method for filtration of a liquid, in particular for the filtration of beer, using a filter aid |
| CN115896357A (en) * | 2022-12-14 | 2023-04-04 | 河南豫鑫糖醇有限公司 | Method for purifying xylose solution |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| DE69608820T2 (en) | ADSORPTION AGENT FOR CAESUMIONS AND METHOD FOR THEIR PRODUCTION | |
| US4622152A (en) | Combined mixing, reacting, drying and filtering device | |
| CN108144353A (en) | A kind of stone sewage filtration treatment method | |
| CN103638734A (en) | Rotating-platform vacuum filtering machine and filtering method | |
| GB2038196A (en) | Filter aid | |
| DE19847191C2 (en) | ITO atomization target and its cleaning process | |
| DE1468318A1 (en) | Process for the filtration of rayon and synthetic film spinning masses by means of filter surfaces onto which a precoat is applied | |
| DE3824147A1 (en) | METHOD AND DEVICE FOR SEPARATING AND SEPARATING DIFFERENT SOLVENTS | |
| US2202806A (en) | Filtering | |
| US3080971A (en) | Method of rotary precoat filtering | |
| IE914089A1 (en) | Process for the purification of aqueous N-methylmorpholine-N-oxide solutions | |
| US2822091A (en) | Filtration of solutions | |
| US4968789A (en) | Process and means for the purification of cellulose ethers | |
| DE2740307C2 (en) | Process for precoat filtration of cellulose acetate solutions | |
| CN102524902A (en) | Vacuum drum filter and operating method thereof prior to ultrafiltration of fruit/vegetable juice | |
| JPH0592113A (en) | Antibacterial air filter and its manufacture | |
| US4547295A (en) | Filtration of wet process superphosphoric acid | |
| SU710584A1 (en) | Suspension filtering method | |
| JPS6219221A (en) | Filtration method and filtration device to remove fine particles from stock solution | |
| SU1406167A1 (en) | Method of filtering concentrated sugar-containing solution | |
| US895063A (en) | Method of preparing a paste or cake of deflocculated material. | |
| SU969296A1 (en) | Filtering material | |
| GB1324572A (en) | Precoat filtration process | |
| US4422946A (en) | Calcined α-alumina filter aids | |
| RU2104748C1 (en) | Filter medium |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |