SPIRAL DESIGNED REACTOR

Abstract: A flow reactor (50) for reacting a feedstock with a pro­ teinaceous preparation immobilized on and within the pores of a support medium (54;70) while traversing a spiral path between adjacent turns of said spiral. A support medium (54;70) has a spacing means (56;60) placed on one surface thereof. The support medium (54;70) and spacing means (56;60) are then wound upon a porous core to form a jelly-­ roll like spiral configuration. The marginal edges of the re­ actor (50) are sealed by provision is made to introduce or remove materials from said core and the free end of the spiral is left open to also introduce or remove materials. In a first form the feedstock is introduced into the core and the reacted feedstock is removed from the spiral feed end. In a second form the introduction and removal of the feedstock and re­ acted feedstock is reversed. The spacing means (56;60) may be a series of ribs (56) on the support medium (54) or may be a net-like sheet (60).

Description: The invention is directed to the field of chemical reactors wherein a feedstock is converted to more desirable product by the interaction of the feedstock with a proteinaceous preparation affixed on or within the pores of a support medium which defines the reactor format. In flow through reactors it is well known that materials which include large particles or which will coagulate in the presence of immobilized proteinaceous preparations will impede the functioning of the reactor. Accordingly, provision must be made to remove these particles prior to introduction to the reactor or the reactor must be frequently backwashed to remove the particles or coagulants. In the former case a filtration system must be used before the reactor stage. For example in the processing of whey an ultrafiltration system is used to remove the fat globules, protein, and/or cheese solids in the whey before it is introduced to the reactor. In the later case when wort is fermented in the making of beer, the flow of the wort must be periodically interrupted to permit the spent enzyme carrier to be backwashed from the reactor so that the beer wort can thereafter flow through the reactor. In each of these approaches additional equipment and time is required depriving the user of all the benefits available in a flow-through system. One approach to a spiral form of reactor is shown in U.S. Patent No 4,292,409 issued 29 September 1981. In this patent a thin spiral channel is formed on one semi-block and the enzyme is immobilized on a second flat semi-block. The two semi-blocks are then joined, and the material to be treated is passed through the spiral channel. Contact with the immobilized enzyme can only occur along the narrow planar surface bounding the spiral channel. Because of the minimal contact between the feedstock and the enzyme only limited conversion of the feedstock can occur. U.S. Patent No 3,809,613 issued 7 May 1974 to Vieth shows a membrane, such as a collagen with an enzyme entrapped in the collagen wrapped about a series of spacer rods and having the general appearance of a spiral. However, the flow is across only one face of the membrane and extends transverse to the spiral rather than along the spiral path. The spiral reactor of the instant invention overcomes the difficulties noted above with respect to prior art by permitting a flow system without the need to filter the materials introduced to the reactor or requiring shut down of the reactor to backwash same. More specifically, the present invention provides a flow reactor for acting upon a feedstock with a proteinaceous preparation immobilized on and within the pores of a support medium comprising: a support medium having a first surface and a second surface and a plurality of random pores; flexible spacing means; porous core means; said spacing means positioned upon said second surface of said support means and both said support means and said spacing means wound about said core means to form a jelly-roll like spiral configuration; first inlet/outlet means coupled to said core means to introduce a feedstock or remove an acted-upon feedstock; and second inlet/outlet means coupled to the free end of said spiral configuration to remove the acted-upon feedstock or introduce a feedstock. Further, the present invention provides a method of forming a flow reactor for reacting a feedstock with a proteinaceous preparation immobilized on the surfaces and within the pores of a support medium comprising the steps of: a) providing a support medium having a first surface and a second surface and a plurality of random pores extending from said first surface and said second surface; b) positioning a flexible spacing means on or integral with said second surface of said support medium; c) winding said support medium and said flexible spacing means upon a porous core means to form a jelly-roll like spiral configuration; d) coupling first inlet/outlet means to said core means; and e) coupling second inlet/outlet means to the free end of said spiral configuration. As will be appreciated, this invention provides a reactor wherein the feedstock introduced into the reactor does not have to be filtered prior to introduction. It is another aim of this invention to provide a reactor which does not have to be regularly backwashed to free its surface of particles or partially reacted feedstock to maintain a sufficient flow through the reactor. It is still another aim of this invention to provide a reactor whose defining walls and the pores therebetween are effectively activated with sufficient of the proteinaceous preparation required to convert the feedstock. It is yet another aim of this invention to provide a reactor in the form of a jelly-roll spiral configuration. It is another aim of this invention to provide a reactor in the form of a jelly-roll spiral configuration wherein substantially all of the convolutions thereof are separated from adjacent convolutions by a predetermined amount. It is another aim of this invention to provide a reactor in the form of a jelly-roll spiral configuration wherein substantially all of the convolutions thereof are separated from adjacent convolutions by a series of raised ribs on one surface of said reactor. It is yet another aim of this invention to provide a reactor in the form of a jelly-roll spiral configuration wherein substantially all of the convolutions thereof are separated from adjacent convolutions by a layer of net-like sheeting on one surface of said reactor. Another aim of this invention is to provide a reactor in the form of a jelly-roll spiral configuration wherein the marginal edges of said reactor are sealed to prevent exit of the feedstock or converted feedstock prior to its desired exit. It is yet another aim of this invention to provide a reactor in the form of a jelly-roll spiral configuration wound upon a porous core and having its marginal edges sealed, wherein feedstock introduced within said porous core is converted and exits at the free end of said spiral. It is still another aim of this invention to provide a reactor in the form of a jelly-roll spiral configuration wound upon a porous core and having its marginal edges sealed, wherein feedstock introduced at the free end of said spiral is converted and exits at said porous core. Other aims and features of the invention will be pointed out in the following description and claims and illustrated in the accompanying drawings, which disclose, by way of example, the principles of the invention, and the best modes which have been contemplated for effecting them. In the drawings in which similar elements are given similar reference characters: FIG 1 is fragmented, sectioned, highly enlarged and idealized side elevation of a flow-through reactor of the type known in the prior art. FIG 2 is a front view of the reactor only of FIG 1. FIG 3 is a side elevation of a reactor system containing a plurality of reactors of the type shown in FIGS 1 and 2 together with accessory supports and piping. FIG 4 is a side elevation, in section, of a jelly-roll spiral configuration reactor constructed in accordance with the concepts of the invention and with the spacing layer omitted for the sake of clarity. FIG 5 is a fragmentary bottom plan view of a material from which the spiral reactor of FIG 4 is formed and showing the ribs formed on one surface thereof. FIG 6 is a front elevational view of a portion of the spiral reactor of FIG 4 and showing the manner in which the ribs on one surface of the material keep adjacent convolutions of the reactor separated. FIG 7 is a fragmentary top plan view of a net-like spacing sheet which can be used with the support medium to construct a reactor in accordance with the concepts of the invention. FIG 8 is a fragmentary side elevation of the spacing sheet of FIG 7 positioned adjacent one surface of the support medium. FIG 9 is a simplified side elevational view of the completed reactor with inlet and outlet pipes connected thereto. Turning now to FIGS 1 to 3 a typical flow-through reactor system of the type known in the prior art is shown. Reactor system 20, as best seen in FIG 3, is comprised of a plurality of reactor modules 22 in a support frame 24 having an input pipe 26 for supplying the feedstock and an output pipe 28 for removing the converted feedstock. Ducts within frame 24 (not shown) serve to distribute the feedstock over the full surface of reactor modules 22 and collect the converted feedstock emerging over the entire surface of such reactor modules 22. As is best seen in FIGS 1 and 2, each reactor module 22 comprises a plurality of stacked microporous sheets 30 having a plurality of pores 32 extending between surfaces 34 and 36 of the sheets 30 (See Fig 1). These pores 32 are not continuous, but rather form a random tortuous pathway. One type of microporous sheet 30 is shown and described in United States Letters Patent No 4,102,746 issued 25 July 1978 in the name of Bruce S. Goldberg and assigned to the assignee of the instant invention. In addition other plastic and rubber sheets can be used. Proteinaceous preparations, for example enzymes, can be immobilized upon the silica fragments on the surface of the sheeting and in the pores of the sheeting employing the techniques described in the 4,102,746 patent and in United States Letters Patent No 4,169,014 issued 25 September 1979 in the name of Bruce S. Goldberg and also assigned to the assignee of the instant invention. Other suitable techniques are also known in the prior art. The marginal edges as well as small portions of the front and back sheets 30 are sealed by a suitable plastic or rubber annular collar 38 which serves to retain the reactor module 22 as an integral unit and prevents the leaking of the feedstock or converted feedstock from the reactor module 22 in a direction other than that desired. Because of the pore 32 size being in the range of 0.01 microns to 100 microns, the presence of fat globules, protein, cheese solids and any materials which can coagulate to form globules can quickly seal the pores 32 and reduce or completely cut off any flow through the reactor system 20 showing the use of a single reactor module 22. The feedstock introduced through input pipe 26 has a number of fat globules 40 dispersed therein. Since these globules 40 are larger than the pore 32 size, either alone or when combined, they soon coat the surface 34 and prevent any of the feedstock from entering into the pores 32. The above described globules 40 must be removed by filtration of the feedstock before it is introduced into the reactor system 20. Alternatively, periodically the feedstock stream must be stopped and the reactor system 20 backwashed by the use of suitable material, such as water, by causing it to reverse-flow from surface 36 to surface 34 against the normal flow through the reactor system 20, which is from surface 34 to surface 36. Both of these approaches are expensive and time consuming and very undesirable in that they increase the cost of the converted feedstock. Tuning now to FIG 4 there is shown a spiral reactor 50 constructed in accordance with the concepts of the invention. The reactor 50 comprises a porous core 52 of appropriate diameter and volume so that it can accept the feedstock introduced into the reactor 50 or alternatively receive the converted feedstock to conduct it from the reactor 50. As in the prior-art flow-through reactor 20, the spiral reactor 50 is predominantly made up of microporous sheets 54 having a proteinaceous preparation immobilized on and in the pores of the sheets 54. However, the sheets 54 are modified to include a plurality of longitudinal ribs 56 on one surface thereon as is shown in FIGS 5 and 6. The ribs 56 contact the adjacent convolutions of the spiral to keep them separated and to establish a series of passages 58 therebetween in conjunction with the spiral convolutions themselves. The height h (see FIG 6) is so chosen that a desired flow-through reactor 50 is attained while insuring proper conversion of the feedstock. The height h of the ribs 56 has been found to be in the range of 0.0127 to 0.0762 cm (0.005" to 0.030") and most particularly about 0.025 cm (0.010"). The height will, of course, have to be altered depending upon the feedstock employed. The total space available for feedstock flow is identified as the void volume and measured in cubic centimeters. Alternatively, a spacing sheet 60 as shown in FIGS. 7 and 8 may be employed instead of the raised ribs 56. The spacing sheet 60 is made of a flexible plastic or rubber material and in an open fish net format to assure light weight and flexibility. Spacing sheet 60 is simply laid atop a microporous sheet 70 as shown in FIG 8. Even though the surfaces of the spacing sheet 60 are substantially flat, the surface of the sheeting is not. The spacing sheet 60 will rest on a number of peaks on the surface of sheet 70, providing, along with the open net format of the sheet 60 sufficient passages to permit the feedstock to pass the spacing sheet 60. The reactor 50 is completed as shown in FIG 9 by encapsulating the entire unit in a suitable housing 80. A first means such as inlet/outlet 82 is provided to gain access to the core 52 and a second means such as outlet/inlet 84 is to provide access to the free end of the reactor. Although it is preferable to introduce the feedstock under suitable pressure into the core 52 of the reactor 50 and remove the converted feedstock from the free end 56 of the reactor 50, the opposite flow pattern can also be used, namely introduce the feedstock to the free end 56 and remove the converted feedstock from core 52. The microporous sheeting together with a spacing layer, whether ribs 56 or spacing sheets 60 are wound upon core 52 to form the spiral configuration shown in FIG 4. As the feedstock flows along the passage 58 it is sufficiently exposed to proteinaceous material attached to active sites on the surface and within the sheet (such as an enzyme) to convert the feedstock to a high degree. The spiral reactor 50 may be formed of a stack of individual microporous sheets 54 0.051 cm (0.020 inches) thick or by winding on itself a 228.6 cm (90 inch) length of 0.051 cm (0.020 inch) thick microporous material to produce a layer 2.54 cm (1 inch) thick and having a width of 7.62 cm (3 inches). Considering that both sides of the sheets 54 are available, a total surface area of 1742 cm² (270 square inches), reduced by the areas of contact of the sheet 54 edges with the housing 80, affords an effective surface area of 1548 cm² (240 square inches). Employing ribs 56 having a height h of 0.025 cm (0.010 inches) and winding the sheets 54 on a porous core 52, 2.54 cm (1 inch) in diameter and 7.62 cm (3 inches) long, results in a reactor 50 having an outside diameter of 5.1 cm (2 inches) and a void volume or flow path volume of between 30 and 40 cubic centimetres. When potted, that is with the housing 80 in place, the layer outside diameter is 7.0 cm (2 3/4 inches) thick. With the enzyme lactase immobilized on the sheets 54, as set out in U.S. Patent No. 4,169,014 identified above, and employing skim milk adjusted to a pH of 5.1 at a flow rate of 10 millilitres per minute at 40°C with a residence time of 3 to 4 minutes, reactor 50 is capable of hydrolyzing 90% of the lactose in the skim milk. If a reactor 50 is constructed using a spacing sheet 60 of a fish net format having open areas equivalent to 70% of the area of a continuous sheet of the same dimensions and a thickness of 0.025 cm (0.010 inches), the available void volume will be 50 cubic centimetres. Using the same feedstock under the same conditions set out in the previous example, approximately the same percentage of lactose in the skim milk will be hydrolyzed. It has been found that in actual practice conversions of the feedstock has reached values as high as 90%. The path through the reactor 50 was assumed generally to be laminar, but in practice it has been found to have a random flow and produce eddys, and in some cases it may also pass through the sheeting 54. The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

Claims: A flow reactor for acting upon a feedstock with a proteinaceous preparation immobilized on and within the pores of a support medium comprising: a support medium having a first surface and a second surface and a plurality of random pores; flexible spacing means; porous core means; said spacing means positioned upon said second surface of said support means and both said support means and said spacing means wound about said core means to form a jelly-roll like spiral configuration; first inlet/outlet means coupled to said core means to introduce a feedstock or remove an acted-upon feedstock; and second inlet/outlet means coupled to the free end of said spiral configuration to remove the acted-upon feedstock or introduce a feedstock. A reactor as defined in claim 1, wherein a feedstock is introduced to said reactor through said first means and the acted-upon feedstock is removed from said reactor through said second means. A reactor as defined in claim 1 or claim 2, wherein said spacing means is formed as a series of longitudinal ribs on said second surface of said support medium which engage said first surface of said support medium as said support medium and spacing means is wound into its spiral configuration. A reactor as defined in claim 3, wherein said ribs have a height from about 0.0127 cm to 0.0762 cm (0.005" to 0.030"). A reactor as defined in claim 1 or claim 2, wherein said spacing means comprises: a sheet material having a generally net-like configuration which rests non-uniformly upon said second surface of said support medium and non-uniformly contacts said first surface of said support medium as said support medium and said spacing means is wound into its spiral configuration. A reactor as claimed in claim 5, wherein said sheet material has a thickness from about 0.0127 cm to 0.0762 cm (0.005" to 0.030"). A reactor as defined in any one of claims 1 to 6, wherein the marginal edges of said support medium and spacing means wound into its spiral configuration are sealed to prevent exit from the reactor at said edges; and port means are afforded in said seal to permit external access to said core means by said first inlet/outlet means and to said free end of said spiral configuration by said second inlet/outlet means. A method for using the reactor of any one of claims 1 to 7, comprising: immobilizing a proteinaceous preparation on the surfaces and within the pores of said support medium; introducing a feedstock to be acted upon by said proteinaceous material into either of said first or second inlet/outlet means and removing an acted-upon feedstock from the remaining inlet/outlet means. The method of forming a flow reactor for reacting a feedstock with a proteinaceous preparation immobilized on the surfaces and within the pores of a support medium comprising the steps of: a) providing a support medium having a first surface and a second surface and a plurality of random pores extending from said first surface and said second surface; b) positioning a flexible spacing means on or integral with said second surface of said support medium; c) winding said support medium and said flexible spacing means upon a porous core means to form a jelly-roll like spiral configuration; d) coupling first inlet/outlet means to said core means; and e) coupling second inlet/outlet means to the free end of said spiral configuration. The method of claim 9, further comprising the step of selecting the thickness of said flexible spacing means to permit optimal flow of a selected feedstock through said reactor.

Inventors: CHEN, RICHARD Y., GOLDBERG, BRUCE S.
Applicants: FMC CORPORATION
Application year: 1985
Main classification: C12M1
IPC codes: B01J16, C12C13, C12N11, C12M1, B01J8, A23C21