CA1208619A - Process in the separation of catalyst particles suspended in liquid - Google Patents
Process in the separation of catalyst particles suspended in liquidInfo
- Publication number
- CA1208619A CA1208619A CA000443852A CA443852A CA1208619A CA 1208619 A CA1208619 A CA 1208619A CA 000443852 A CA000443852 A CA 000443852A CA 443852 A CA443852 A CA 443852A CA 1208619 A CA1208619 A CA 1208619A
- Authority
- CA
- Canada
- Prior art keywords
- liquid
- filter
- backwashing
- filters
- particles
- 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.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D37/00—Processes of filtration
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D37/00—Processes of filtration
- B01D37/04—Controlling the filtration
-
- 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
- B01J25/00—Catalysts of the Raney type
- B01J25/04—Regeneration or reactivation
-
- 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
- B01J38/00—Regeneration or reactivation of catalysts, in general
- B01J38/48—Liquid treating or treating in liquid phase, e.g. dissolved or suspended
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Catalysts (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Physical Or Chemical Processes And Apparatus (AREA)
Abstract
CANADIAN PATENT APPLICATION
OF
BENGT GUSTAF FRANZ?N
FOR
PROCESS IN THE SEPARATION OF CATALYST PARTICLES
SUSPENDED IN LIQUID
Abstract of the Disclosure:
A process in the separation of solid catalyst par-ticles suspended in liquid is described. After passage of a reaction chamber, the liquid is caused to pass through one or more filters retaining the suspended catalyst particles in the reaction chamber. The filter is periodically cleaned from deposits by backwashing which is carried out with an amount of liquid greater than the amount of liquid that can be enclosed in the filter or filters. The specific backwashing flow through the filter or filters is so adapted that it will be greater than the specific filtrate flow through the filter or filters during the first 20 seconds after backwashing.
OF
BENGT GUSTAF FRANZ?N
FOR
PROCESS IN THE SEPARATION OF CATALYST PARTICLES
SUSPENDED IN LIQUID
Abstract of the Disclosure:
A process in the separation of solid catalyst par-ticles suspended in liquid is described. After passage of a reaction chamber, the liquid is caused to pass through one or more filters retaining the suspended catalyst particles in the reaction chamber. The filter is periodically cleaned from deposits by backwashing which is carried out with an amount of liquid greater than the amount of liquid that can be enclosed in the filter or filters. The specific backwashing flow through the filter or filters is so adapted that it will be greater than the specific filtrate flow through the filter or filters during the first 20 seconds after backwashing.
Description
6~
The present invention relates to a process in the separation of solid catalyst particles suspended in liquid.
It is customary, in process technology, ta carry out reactions between sas and liquid or one or more substances dissolved in liquid with the aid of cata-lytically active solid substances present in liquids.
Examples of such reactions are hydrogenation, oxidation and halogenation~ The catalyst may be in the form of a fixed bed through which the liquid passes, or a sus-pension of particles which t by the application of energy, are held freely suspended in the lîquid. The suspension catalyst offers certain advantages, such as being suc cessively renewable in continuous processes. In several cases, the dispersed catalyst retains its activity for a considerable period of time, and if the reaction is to proceed continuously, the catalyst must therefore be retained in or constantly recycled to the reaction chamber through which the liquid passes. This can ~e accomplished by wi~hdrawing the finally reacted liquid .
through a filter retaining the catalyst particlesO
In general, the instantaneous filtrate flow through a filter is directly proportional to the ilter surface and the pressure drop across said surface and inversely proportional to the viscosity of the liquidl the total amount of deposit on the filter surface, and a constant which depends on the permeability of the deposit.
- . It is already known tha~ a filter surface can be ~z~ 9 instantaneously freed from deposits by so-called back-washing, implying that liquid is pressed through the filter in a direction opposite to that of the normal iltrate fLow. U.S. patent specification 2,990,238 teach-es backwashing with the aid of a piston or diaphragm pump which in one stroke direction exhausts filtrate and in the other stroke direction presses a part of ~he filtrate back through the filterc As will appear from Fig. 1 of the said U.S. patent specification, only half the available time is utilised for the withdrawal of filtratet regardless of the pump stroke frequency which is given as 1 500 strokes per minute. Furthermore, it appears that the backflow should amount to 20-70% of the amount of filtrate exhausted, and this results in a further coxresponding reduction of the product flow. According to this procedure, the backwashing flow cannot be greater than the filtrate flow.-German patent specification 1,542,089 shows a filterarrangement for use in con~inuous hydrogena~ion. The filtrate is led out through a stationary centrifugal pump. When the pump is started, iltrate is pressed back through the filter. Hydrogenation is carried out by the circulation of llquid and hydrogen gas dispersed in the llquid, the flow rate according Example 1 being 0.7-2.8 m~s. The fllter is placed laterally of the cir-culation flow, for which reason the flow rate during filtratlon will approach zero at the filter top. Accord-ing to the description, backwashing can be effectedfor a few seconds. The concentration of solid particles is given as 1-5 g/1 in the Examples, British patent specification gS9,583 discloses the hydrogenation of a liquid consisting of alkyl anthra-quinone dissolved in organic solvents, This hydrogenation is a partial process in the well-known anthraquinone process for the production of hydr,ogen peroxide. The hydrogenation catalyst susp~nded in the solution is retained on a filter which is periodically backwashed with the aid of a pump. No further information about the backwashing and the catalyst is given.
German patent specification 1,272 t 292 exemplifies the same hydrogsnation process~ The filter medium employed is a porous solid carbon material. The anthraquinone solution contains as catalyst 0.07% by weight palladium black. The particle size of the catalyst is 0.01-1 ~m.
The filtrate flow is 0.46 m3 per hour and m2 of filter surface. According to the description~ the carbon fil ter is to be backwashed for 3-10 s at intervals of 20-30 min.
For the hydroyenation comprised by the anthraquinone process, use is made, in addition to palladium black J
also of Raney nickel or, for example, palladium provided on a so-called carrier, usually a ceramic materialO
These suspension catalysts are used in concentrations higher than 5 g per litre of llquid, and the average particle size is greater than 1 ~m.
6~
The use of such catalysts has made the dischar~e of product liquid through filters so difficult that the catalyst separation in some cases has been carried out by means of hydrocyclones and/or centrifuges.
The present invention provides a process in the separation of solid particles suspended in liquid, such as Raney nickel, said particles being catalytically active in continuous chemical processes, such as the hydrogenation process cornprised by the anthraquinone process in the production of hydrogen peroxide, more than 75% of said particles hasving a particle size greater than 1 ~m, and said particles being present in a con-centration which~ on an average, is maintained above 5 g per litre of liquid, the liquid containing the reac~
tion product being caused, after passage of a reaction chamber, to pass through one or more filters, the solid paxticles thus retained on the filter surfaces being , released by periodic backwashing and then resuspended in the reaction chamber. The process of the invention is characterised ln that backwashing is carried out with an amount of 11quld which is greater than the amount of liquid that can be enclosed within the filter or filters, and in that the specific backwashing flow through the filter or filters is so adapted that it will be greater than the specific filtrate flow throuyh the filter or filters during the first 20 seconds after backwashing ~ ~
The process o~ the present invention makes it pos-136~9 sible to obtain, under long-time continuous conditions, an effective specific amount of filtrate which is greater than 0.5 m3 per hour and m2 of filter surface; also when the catalyst concentration is greater than 5 g per litre of liquid and/or the deposit on the filter has low permeability.
The deposit on ~he filter constitutes not only an obstruction; it also serves as a filter intercept ing those particles which otherwise could have passed through the pores in the fixed filter. During each back-washing, the filter surface is exposed for such penetra-tion. In view hereof, and in order to obtain maximum discharge of the product flow, it has pro~ed to be most advantageous to effect backwashing at intervals from 1/3 minute to twenty minutes, depending upon the con-centration of solid particles in the liquid and the permeability of the deposit.
Backwashing is intended not only to wash off the outer deposit on the filter surface, but also, if pos-sible, to wash back any particles ~hat may have pene-trated into the pore system of the filter medium.
To this end~ the backwashing according to the in-vention must be carried out with an amount of liquid which is greater than the one enclosed in the filter medium, preferably 2-10 times greater than this amount.
Furthermore, the speciflc backwashing flow must be great-er than the specific filtrate flow during the first twenty seconds after backwashing. It has also proved ~z~
to be advantageous to impart to the filter surfaces facing the reaction chamber a movement adjacent said filter surfaces which, on an average, is greater than 0.1 m/s.
Preferably, more than 75% of the catalyst particles have a particle size greater than 1 um.
The invention will be explained in greater detail below, reference being had to the following Examples and the accompanying drawing.
EXAM~LE 1 (for comparison3 Fig~ 1 illustrates the filtration run during hydro-genation of anthraquinone derivatives dissolved in or-gan~c solvents. The solution contained 110 g/l of sus-pended Raney nickel having a particle size of from about 1 ~m up to 0.5 mm, more than 75% of said particles hav-ing a particle siæe greater than 1 ~m. Th~ filter medium consisted of sintered particles of acidproof steeL. The material thickness was 2 mm, and the porssity amount-ed to about 40~. Maximum pore width was 8 ~m~
Before the fil~ration run, the pore system of the . .
filter medium had been chemically cleaned~ Through appli-cation of mechanlcal energy, a turbulent flow ra~e which, on an average~ was greater than 0 1 m/s, was imparted to the solution at the filter surface~ Backwashing was carried out for 6 seconds, and the filtrat~ flow was then shut down for altogether 12 seconds. Backwashing was carried out at intervals of 10 minutes.
After deduction of the hydrogenated solution back-.
~2~861 9 washed through the filter, the average filtrate flow during each 10-min. period was about 1.3 m3 per m2 of filter surface and hour. After continuous operation for ten days, the effective filter flow was less than 1.0 m3tm2. The hydrogenation formed part of the anthra-quinone process for the production of hydrogen peroxide.
EXAM
Fig. 2 illustrates the filtra~ion run under the same conditions as in Example 1. Backwashing was car-ried out for 2 seconds during each minute. The average effective filtrate flow was 2.25 m3/m2/hour~ After con-tinuous operation for 60 days the e~fective filtrate flow was about 2.1 m3/m2/houx.
.
The present invention relates to a process in the separation of solid catalyst particles suspended in liquid.
It is customary, in process technology, ta carry out reactions between sas and liquid or one or more substances dissolved in liquid with the aid of cata-lytically active solid substances present in liquids.
Examples of such reactions are hydrogenation, oxidation and halogenation~ The catalyst may be in the form of a fixed bed through which the liquid passes, or a sus-pension of particles which t by the application of energy, are held freely suspended in the lîquid. The suspension catalyst offers certain advantages, such as being suc cessively renewable in continuous processes. In several cases, the dispersed catalyst retains its activity for a considerable period of time, and if the reaction is to proceed continuously, the catalyst must therefore be retained in or constantly recycled to the reaction chamber through which the liquid passes. This can ~e accomplished by wi~hdrawing the finally reacted liquid .
through a filter retaining the catalyst particlesO
In general, the instantaneous filtrate flow through a filter is directly proportional to the ilter surface and the pressure drop across said surface and inversely proportional to the viscosity of the liquidl the total amount of deposit on the filter surface, and a constant which depends on the permeability of the deposit.
- . It is already known tha~ a filter surface can be ~z~ 9 instantaneously freed from deposits by so-called back-washing, implying that liquid is pressed through the filter in a direction opposite to that of the normal iltrate fLow. U.S. patent specification 2,990,238 teach-es backwashing with the aid of a piston or diaphragm pump which in one stroke direction exhausts filtrate and in the other stroke direction presses a part of ~he filtrate back through the filterc As will appear from Fig. 1 of the said U.S. patent specification, only half the available time is utilised for the withdrawal of filtratet regardless of the pump stroke frequency which is given as 1 500 strokes per minute. Furthermore, it appears that the backflow should amount to 20-70% of the amount of filtrate exhausted, and this results in a further coxresponding reduction of the product flow. According to this procedure, the backwashing flow cannot be greater than the filtrate flow.-German patent specification 1,542,089 shows a filterarrangement for use in con~inuous hydrogena~ion. The filtrate is led out through a stationary centrifugal pump. When the pump is started, iltrate is pressed back through the filter. Hydrogenation is carried out by the circulation of llquid and hydrogen gas dispersed in the llquid, the flow rate according Example 1 being 0.7-2.8 m~s. The fllter is placed laterally of the cir-culation flow, for which reason the flow rate during filtratlon will approach zero at the filter top. Accord-ing to the description, backwashing can be effectedfor a few seconds. The concentration of solid particles is given as 1-5 g/1 in the Examples, British patent specification gS9,583 discloses the hydrogenation of a liquid consisting of alkyl anthra-quinone dissolved in organic solvents, This hydrogenation is a partial process in the well-known anthraquinone process for the production of hydr,ogen peroxide. The hydrogenation catalyst susp~nded in the solution is retained on a filter which is periodically backwashed with the aid of a pump. No further information about the backwashing and the catalyst is given.
German patent specification 1,272 t 292 exemplifies the same hydrogsnation process~ The filter medium employed is a porous solid carbon material. The anthraquinone solution contains as catalyst 0.07% by weight palladium black. The particle size of the catalyst is 0.01-1 ~m.
The filtrate flow is 0.46 m3 per hour and m2 of filter surface. According to the description~ the carbon fil ter is to be backwashed for 3-10 s at intervals of 20-30 min.
For the hydroyenation comprised by the anthraquinone process, use is made, in addition to palladium black J
also of Raney nickel or, for example, palladium provided on a so-called carrier, usually a ceramic materialO
These suspension catalysts are used in concentrations higher than 5 g per litre of llquid, and the average particle size is greater than 1 ~m.
6~
The use of such catalysts has made the dischar~e of product liquid through filters so difficult that the catalyst separation in some cases has been carried out by means of hydrocyclones and/or centrifuges.
The present invention provides a process in the separation of solid particles suspended in liquid, such as Raney nickel, said particles being catalytically active in continuous chemical processes, such as the hydrogenation process cornprised by the anthraquinone process in the production of hydrogen peroxide, more than 75% of said particles hasving a particle size greater than 1 ~m, and said particles being present in a con-centration which~ on an average, is maintained above 5 g per litre of liquid, the liquid containing the reac~
tion product being caused, after passage of a reaction chamber, to pass through one or more filters, the solid paxticles thus retained on the filter surfaces being , released by periodic backwashing and then resuspended in the reaction chamber. The process of the invention is characterised ln that backwashing is carried out with an amount of 11quld which is greater than the amount of liquid that can be enclosed within the filter or filters, and in that the specific backwashing flow through the filter or filters is so adapted that it will be greater than the specific filtrate flow throuyh the filter or filters during the first 20 seconds after backwashing ~ ~
The process o~ the present invention makes it pos-136~9 sible to obtain, under long-time continuous conditions, an effective specific amount of filtrate which is greater than 0.5 m3 per hour and m2 of filter surface; also when the catalyst concentration is greater than 5 g per litre of liquid and/or the deposit on the filter has low permeability.
The deposit on ~he filter constitutes not only an obstruction; it also serves as a filter intercept ing those particles which otherwise could have passed through the pores in the fixed filter. During each back-washing, the filter surface is exposed for such penetra-tion. In view hereof, and in order to obtain maximum discharge of the product flow, it has pro~ed to be most advantageous to effect backwashing at intervals from 1/3 minute to twenty minutes, depending upon the con-centration of solid particles in the liquid and the permeability of the deposit.
Backwashing is intended not only to wash off the outer deposit on the filter surface, but also, if pos-sible, to wash back any particles ~hat may have pene-trated into the pore system of the filter medium.
To this end~ the backwashing according to the in-vention must be carried out with an amount of liquid which is greater than the one enclosed in the filter medium, preferably 2-10 times greater than this amount.
Furthermore, the speciflc backwashing flow must be great-er than the specific filtrate flow during the first twenty seconds after backwashing. It has also proved ~z~
to be advantageous to impart to the filter surfaces facing the reaction chamber a movement adjacent said filter surfaces which, on an average, is greater than 0.1 m/s.
Preferably, more than 75% of the catalyst particles have a particle size greater than 1 um.
The invention will be explained in greater detail below, reference being had to the following Examples and the accompanying drawing.
EXAM~LE 1 (for comparison3 Fig~ 1 illustrates the filtration run during hydro-genation of anthraquinone derivatives dissolved in or-gan~c solvents. The solution contained 110 g/l of sus-pended Raney nickel having a particle size of from about 1 ~m up to 0.5 mm, more than 75% of said particles hav-ing a particle siæe greater than 1 ~m. Th~ filter medium consisted of sintered particles of acidproof steeL. The material thickness was 2 mm, and the porssity amount-ed to about 40~. Maximum pore width was 8 ~m~
Before the fil~ration run, the pore system of the . .
filter medium had been chemically cleaned~ Through appli-cation of mechanlcal energy, a turbulent flow ra~e which, on an average~ was greater than 0 1 m/s, was imparted to the solution at the filter surface~ Backwashing was carried out for 6 seconds, and the filtrat~ flow was then shut down for altogether 12 seconds. Backwashing was carried out at intervals of 10 minutes.
After deduction of the hydrogenated solution back-.
~2~861 9 washed through the filter, the average filtrate flow during each 10-min. period was about 1.3 m3 per m2 of filter surface and hour. After continuous operation for ten days, the effective filter flow was less than 1.0 m3tm2. The hydrogenation formed part of the anthra-quinone process for the production of hydrogen peroxide.
EXAM
Fig. 2 illustrates the filtra~ion run under the same conditions as in Example 1. Backwashing was car-ried out for 2 seconds during each minute. The average effective filtrate flow was 2.25 m3/m2/hour~ After con-tinuous operation for 60 days the e~fective filtrate flow was about 2.1 m3/m2/houx.
.
Claims (4)
1. A process in the separation of solid particles suspended in liquid, said particles being catalytically active in continuous chemical processes, such as the hydro-genation process comprised by the anthraquinone process in the production of hydrogen peroxide, more than 75% of said particles having a particle size greater that 1 µm, and said particles being present in a concentration which, on an - -average, is maintained above 5 g per litre of liquid, the liquid containing the reaction product being caused, after passage of a reaction chamber, to pass through one or more filters, the solid particles thus retained on the filter surfaces being released by periodic backwashing and then resuspended in the reaction chamber, characterised in that backwashing is carried out with an amount of liquid which is greater than the amount of liquid that can be enclosed within the filter or filters, and in that the specific backwashing flow through the filter or filters is so adapted that it will be greater than the specific filtrate flow through the filter or filters during the first 20 seconds after backwashing.
2. A process in the separation of Raney nickel solid particles suspending in liquid, said particles being catalytically active in continuous chemical processes, such as the hydrogenation process comprised by the anthraquinone process in the production of hydrogen peroxide, more than 75% of said particles having a particle size greater than 1 µm, and said particles being present in a concentration which, on an average, is maintained above 5 g per litre of liquid, the liquid containing the reaction product being caused, after passage of a reaction chamber, to pass through one or more filters, the solid particles thus retained on the filter surfaces being released by periodic backwashing and then resuspended in the reaction chamber, characterised in that backwashing is carried out with an amount of liquid which is greater than the amount of liquid that can be enclosed within the filter or filters, and in that the specific backwashing flow through the filter or filters is so adapted that it will be greater than the specific filtrate flow through the filter or filters during the first 20 seconds after backwashing.
3. A process as claimed in claim 1 or claim 2 character-ised in that backwashing is carried out with an amount of liquid which is 2-10 times greater than the amount of liquid that can be enclosed within the filter or filters.
4. A process as claimed in claim 1 or claim 2 character-ised in that a movement which, on an average, is greater than 0.1 m/s is imparted to the liquid at the filter surfaces facing the reaction chamber.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE8207376A SE8207376L (en) | 1982-12-23 | 1982-12-23 | PROCEDURE FOR SEPARATION OF VETERINARY SUSPENDED CATALYST PARTICLES |
| SE8207376-8 | 1982-12-23 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1208619A true CA1208619A (en) | 1986-07-29 |
Family
ID=20349129
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000443852A Expired CA1208619A (en) | 1982-12-23 | 1983-12-20 | Process in the separation of catalyst particles suspended in liquid |
Country Status (3)
| Country | Link |
|---|---|
| CA (1) | CA1208619A (en) |
| NO (1) | NO834785L (en) |
| SE (1) | SE8207376L (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5348657A (en) * | 1992-05-25 | 1994-09-20 | Degussa Aktiengesellschaft | Process for the separation of catalyst-free working solution from the hydrogenation circuit of the anthraquinone process for the production of hydrogen peroxide |
| US5534149A (en) * | 1994-05-31 | 1996-07-09 | Degussa Aktiengesellschaft | Method of separating catalyst-free working solution from the hydrogenation cycle of the anthraquinone method for the production of hydrogen peroxide |
-
1982
- 1982-12-23 SE SE8207376A patent/SE8207376L/en not_active Application Discontinuation
-
1983
- 1983-12-20 CA CA000443852A patent/CA1208619A/en not_active Expired
- 1983-12-22 NO NO834785A patent/NO834785L/en unknown
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5348657A (en) * | 1992-05-25 | 1994-09-20 | Degussa Aktiengesellschaft | Process for the separation of catalyst-free working solution from the hydrogenation circuit of the anthraquinone process for the production of hydrogen peroxide |
| US5534149A (en) * | 1994-05-31 | 1996-07-09 | Degussa Aktiengesellschaft | Method of separating catalyst-free working solution from the hydrogenation cycle of the anthraquinone method for the production of hydrogen peroxide |
Also Published As
| Publication number | Publication date |
|---|---|
| SE8207376L (en) | 1984-06-24 |
| NO834785L (en) | 1984-06-25 |
| SE8207376D0 (en) | 1982-12-23 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |