BIOREACTOR CLEANING SYSTEM WITH AN ACID TANK AND A DEVICE FOR NEUTRALIZING THE ACID

Abstract

A bioreactor cleaning system for cleaning a bioreactor in a rail vehicle. A suction unit, a supply unit, an electronic control unit for actuating the suction unit and the supply unit, an acid tank, a collection tank for receiving a liquid suctioned out of the bioreactor, and a freshwater connection are provided. The bioreactor cleaning system comprises a metering unit which has acid canister connections, base canister connections, an acid metering device which can be connected to the acid canister connections and the acid tank, and a base metering device which can be connected to the base canister connections and the acid tank. Additionally, a mixer is provided in order to mix the different liquids.

Claims

1-27. (canceled)

28. A bioreactor cleaning system for cleaning a bioreactor, comprising: a suction unit for suctioning liquid from the bioreactor, the suction unit having an suction connection for connecting to the bioreactor; a supply unit for supplying liquid into the bioreactor, the supply unit having at least one supply connection for connecting to the bioreactor; an electronic control unit for controlling the suction unit and the supply unit; an acid tank for receiving an aqueous acid solution; a collection tank for receiving liquid suctioned from the bioreactor; a freshwater connection for supplying the bioreactor cleaning system with freshwater; wherein the supply unit is connected to the freshwater connection and the acid tank to selectively provide freshwater and/or aqueous acid solution to the supply connection; wherein the suction unit for suctioning liquid from the bioreactor is selectively connectable to the acid tank or the collection tank for supplying acid solution suctioned from the bioreactor to the acid tank and for supplying substantially pH-neutral residual fluid suctioned from the bioreactor to the collection tank; a dosing unit, which has one or more acid canister ports for connecting acid canisters and one or more base canister ports for connecting base canisters; an acid doser connectable on the input side to the one or more acid canister ports and on the output side to the acid tank, and a base doser connectable on the input side to the one or more base canister ports and on the output side to the acid tank; and a mixer, wherein the mixer can be connected on the input side to a freshwater connection and the acid dosing unit and/or base dosing unit, and on the output side to the acid tank in order to supply the acid tank with a solution usable to neutralize the acid solution present in the acid tank.

29. The bioreactor cleaning system of claim 28, including a first pH sensor for detecting a first pH value of a fluid supplied to the acid tank and for providing a first pH signal to the electronic control unit.

30. The bioreactor cleaning system according to claim 29, including a second pH sensor for detecting a second pH value of a liquid suctioned via the suction connection.

31. The bioreactor cleaning system according to claim 28, wherein the acid doser comprises an acid ejector which can be connected to the freshwater connection on the inlet side.

32. The bioreactor cleaning system according to claim 28, wherein the base doser comprises a base ejector which can be connected to the freshwater connection on the inlet side.

33. The bioreactor cleaning system according to claim 28, wherein the mixer comprises a throttle for throttling the freshwater supplied to the mixer.

34. The bioreactor cleaning system according to claim 28, further including: a first flow meter for measuring the freshwater supplied to the mixer and/or the acid doser and/or the base doser.

35. The bioreactor cleaning system according to claim 34, further including: a second flow meter for measuring the acid supplied to the acid doser.

36. The bioreactor cleaning system according to claim 28, wherein the suction unit and/or the supply unit are operable to pump liquid out of the acid tank and/or bioreactor to the mixer and back into the acid tank and/or bioreactor.

37. The bioreactor cleaning system according to claim 30, wherein the suction unit and/or the supply unit are operable to pump liquid out of the acid tank and/or bioreactor to the first and/or second pH sensor and back into the acid tank and/or bioreactor.

38. The bioreactor cleaning system according to claim 28, wherein the electronic control unit is adapted to: determine an acid quality value indicating a quality of aqueous acid solution present in the acid tank; compare the determined acid quality value to a predetermined acid comparison value; and depending on the comparison: initiate neutralization of the aqueous acid solution in the acid tank.

39. The bioreactor cleaning system according to claim 38, wherein the acid quality value is the first pH value, and the electronic control unit is adapted to: determine a first pH value of aqueous acid solution present in the acid tank; compare the determined first pH value with a predetermined pH threshold value; and in the event that the determined first pH value exceeds the pH threshold value: initiate neutralization of the aqueous acid solution in the acid tank.

40. The bioreactor cleaning system according to claim 38, wherein the electronic control unit is adapted to determine and load the acid comparison value and/or predetermined pH threshold value (SpH) from a database.

41. The bioreactor cleaning system according to claim 30, wherein the electronic control unit is adapted to neutralize the aqueous acid solution present in the acid tank, while the suction unit and/or the supply unit pump the liquid out of the acid tank to the first or second pH sensor and back into the acid tank, to cause the base doser to dispense base into the mixer until a neutral target pH is reached in the acid tank.

42. A method for operating a bioreactor cleaning system, preferably a bioreactor cleaning system according to claim 28, comprising the steps: determining an acid quality value indicating a quality of an aqueous acid solution present in an acid tank of the bioreactor cleaning system; comparing the determined acid quality value to a predetermined acid comparison value; and depending on the comparison: initiate neutralization of the aqueous acid solution in the acid tank.

43. The method of claim 42, wherein the acid quality value is a first pH-value, and wherein the method comprises the steps of: determining a pH-value of aqueous acid solution present in the acid tank; comparing the determined first pH-value with a predetermined pH threshold value; and in the event that the determined first pH-value exceeds the pH threshold value: initiate neutralization of the aqueous acid solution in the acid tank.

44. The method according to claim 42, including: determining and loading the acid comparison value and/or the predetermined pH threshold from a database.

45. The method according to claim 42, including: pumping liquid out of the acid tank to a mixer of the bioreactor cleaning system and back into the acid tank.

46. The method of claim 42, including: mixing in the mixer acid and/or base and/or freshwater.

47. The method according to claim 42, including: determining a first pH-value downstream of the mixer.

48. The method according to any one of claim 47, including: determining a second pH-value upstream of the mixer.

49. The method according to claim 48, including: depending on the first and/or second pH-value, mixing in the mixer acid and/or base to achieve a neutral target pH in the acid tank.

50. The method of claim 49, wherein the neutral target pH is in a range of 6.5 to 10.

51. The method according to claim 50, including the step of: when the neutral target pH is reached: pumping the liquid from the acid tank into a collection tank of the bioreactor cleaning system and/or a disposal drain.

52. The method according to claim 42, including: dependent on the comparison: supplying liquid from the acid tank to the bioreactor for cleaning the bioreactor; and extracting liquid from the bioreactor and supplying the extracted liquid to the acid tank.

53. The method of claim 52, including: introducing air in the form of bubbles into the liquid when supplying the liquid to the bioreactor.

54. A computer program product comprising code means which, when executed on a computer, causes a bioreactor cleaning system to perform the steps according to the method of claim 42.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Further advantages, features, and details of the invention will be apparent from the following description of preferred embodiments and from the drawings. The drawings show in:

[0036] FIG. 1 is a schematic representation of the bioreactor cleaning system in connection with a bioreactor as well as further elements;

[0037] FIG. 2 is a schematic side view of the bioreactor cleaning system, partially cut free;

[0038] FIGS. 3a-3d are four representations of acid canisters;

[0039] FIG. 4 is a circuit diagram of the bioreactor cleaning system;

[0040] FIG. 5 is a cross section of an ejector;

[0041] FIG. 6 is a schematic circuit diagram of a mixer with further elements; and

[0042] FIG. 7 is a diagram of the neutralization of the aqueous acid solution.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0043] A bioreactor cleaning system 1 can be designed as a mobile bioreactor cleaning system, as shown in FIG. 1, or as a stationary bioreactor cleaning system. A mobile bioreactor cleaning system can typically be moved to a train in which a bioreactor 2 is provided. Bioreactors 2 in trains are generally known and will not be further described in detail here. In FIG. 1, a vertically oriented bioreactor 2 is shown as an example, with a solids tank 4, a liquid tank 5, and a sanitizer 6, which has an outlet 7, for draining liquid. A filter basket 8 is provided in the solids tank 4, into which both a 2-inch hose 9 terminates near the bottom and a cleaning nozzle 10 is provided to supply water under high pressure to the solids tank 4 to clean off a filter cake built up in the filter basket 8. A 1-inch connection 11 is further provided on the liquid tank 5 to draw or suction liquid from or supply liquid to the liquid tank 5. Further, the bioreactor 2 comprises a controller 12 that can, for example, read sensors of the bioreactor 2.

[0044] The bioreactor cleaning system 1 has connections via which it can be connected to the bioreactor 2. For example, in order to suction liquid from the bioreactor 2, the bioreactor cleaning system 1 has a suction connection 20, which can be connected to the 1-inch connection 11 of the liquid tank 5 of the bioreactor 2 via a suction line 22. Furthermore, the bioreactor cleaning system 1 has a supply connection 24, which can be connected to the 2-inch hose 9 of the bioreactor 2 via a feed line 26, in order to feed liquid into the bioreactor 2, more specifically the solids tank 4, via the latter. The bioreactor cleaning system 1 also has a high-pressure connection 28, which can be connected to the cleaning nozzle 10 via a high-pressure hose 30, and an electronic control connection 32, which can be connected to the control 12 of the bioreactor 2 via a signal line 34.

[0045] The bioreactor cleaning system 1 further has a disposal connection 36, via which the bioreactor cleaning system 1 can be connected to an external tank 38, which is connected to an external vacuum source 39, for extracting liquid from the bioreactor cleaning system 1. On the input side, the bioreactor cleaning system 1 has a power connection 40 and a fresh water connection 42.

[0046] Inside the bioreactor cleaning system 1 (FIG. 2), the latter has an electronic control unit 44 which has a memory with program code and a processor for executing the program code. The electronic control unit 44 controls various functions of the bioreactor cleaning system 1, as is apparent, in particular, from the further description. For example, the electronic control unit 44 controls a pump 46 as well as a high pressure pump 48. The pump 46 can be used to provide a vacuum at the suction port 20 as well as to pump fluid to the supply connection 24. The high pressure pump 48 is used to provide a fluid at high pressure to the high pressure port 28. Furthermore, a collection tank 50 and an acid tank 52 are provided inside the bioreactor cleaning system 1, wherein a first level sensor 51 is provided for the collection tank 50 and a second level sensor 53 is provided for the acid tank 52.

[0047] A plurality of acid canisters 56 and a plurality of base canisters 58 are provided in a lower portion of the bioreactor cleaning system 1. The acid canisters 56 and base canisters 58 are respectively housed in acid drawers 57 and base drawers 59 provided for the purpose. FIG. 3b shows two acid canisters 56 in detail. A suction lance 60 is arranged at the acid canister 56, which can be connected to the acid tank 52 via further valves, as will be described with reference to FIG. 4. Adjacent to the suction lance 60, which is inserted into a suction port 61, an aeration valve 62 is provided. The suction lance 60 has a screw cap 63 (cf. FIG. 3c), a lance body 64, and a foot valve 65 with a fixed filter. If one of the canisters 56, 58 has to be changed, the suction lance 60 can be inserted in lance holders 66a, 66b provided for this purpose on the respective drawers so that it is not damaged.

[0048] FIG. 4 illustrates a circuit diagram or layout of the bioreactor cleaning system 1. Power connection 40 is not shown, nor is electronic control unit 44. The circuit diagram according to FIG. 4 is divided into three systems, with system boundaries A, B, and C. System boundary A in the right-hand side of FIG. 4 comprises, in addition to suction connection 20, supply connection 24 and high-pressure connection 26, a pump and valve unit 70, which is shown here only schematically as a block, but inside which a plurality of valves, conduits, sensors, and the like may be arranged. As part of the pump and valve unit 70, pump 46 is shown here, for example, as well as schematically a suction unit 72 and a supply unit 74 of the bioreactor cleaning system 1. Suction unit 72 serves to suction, extract, or draw liquid from bioreactor 2 and has suction connection 20 for this purpose. Pump 46 acts thereon to provide a vacuum at suction connection 20. Furthermore, supply unit 74 is formed in the pump and valve unit 70 and has supply connection 24.

[0049] A dosing unit 80 is within system boundary B, as are the plurality of acid canisters 56 and plurality of base canisters 58. Freshwater connection 42 is shown here within system B, more specifically associated with dosing unit 80. In the embodiment shown, dosing unit 80 has four acid canister connections 82a, 82b, 82c, 82d and two base canister connections 84a, 84b. Dosing unit 80 is then in turn connected to a structural unit within system boundary C, in which collection tank 50 and acid tank 52 are also shown in the embodiment present embodiment (FIG. 5). Likewise, first level sensor 51 and second level sensor 53 are shown within this system boundary, as is disposal connection 36. System boundaries A, B, and C are for illustrative purposes only, but have no structural influence beyond that. In certain embodiments, however, the system boundaries may form structural boundaries.

[0050] As part of a cleaning of bioreactor 2, residual fluid present in bioreactor 2, in particular, liquid tank 5, can now first be suctioned in the first step with suction unit 72 via suction connection 20 under the action of pump 46. This residual fluid is then supplied to collection tank 50 via a first line L1. For this purpose, a valve BV82, which is preferably designed as a ball valve, is opened, which is preferably initiated by electronic control unit 44. A first manual valve HA1 is arranged at suction connection 20, which is to be opened manually. Downstream of this in the direction of the pump and valve unit 70, a first flow measuring unit VF1 comprising a capacitive sensor is arranged. By means of the capacitive sensor of flow measuring unit VF1, the presence of liquid can be determined in order to close the line for the case that no liquid is present, or to provide no further vacuum, or to use it at another position. Flow measuring unit VF1 is also connected to electronic control unit 44 to provide appropriate flow signals thereto. If the residual fluid has now been extracted from bioreactor 2, it may be useful and necessary to first either carry out mechanical cleaning using the nozzle head 10, or to introduce liquid via 2-inch hose 9 in order to detect the permeability of filter basket 8. For this purpose, freshwater can be supplied via supply connection 24, for example. In this embodiment, a second manual valve HA2 is to be opened manually for providing the freshwater supply. The supply unit 74 is connected to freshwater connection 42 via a second line L2 and receives freshwater from the latter. Supply unit 74 can then forward this liquid to supply connection 24 using the action of pump 46.

[0051] In the course of chemical cleaning, bioreactor 2 is cleaned by means of a chemical substance, namely, in particular, an aqueous acid solution. Here, it may be necessary to first prepare the aqueous acid solution. In the embodiment shown here, this is done by means of dosing unit 80. Dosing unit 80 is connected to freshwater connection 42 via a third line L3. A valve BV78, preferably a ball valve, is placed in third line L3, which can be controlled by means of electronic control unit 44. Downstream, a first flow sensor FT60, a pressure sensor PT60, and a second pH sensor QT60 are arranged. Downstream of second pH sensor QT60, the line branches into a fourth line L4 leading to an acid doser 86, a fifth line L5 leading to a base doser 88, and a sixth line L6 forming a bypass for freshwater to acid doser 86 and base doser 88. Acid dosing unit 86, which in this embodiment is designed as an acid ejector 87 (cf. FIG. 5), not only receives freshwater via fourth line L4, but is also connectable or connected to acid canister connections 82a-82d via a seventh line L7. More specifically, seventh line L7 is connected to acid canister ports 82a-82d via a first solenoid valve MV71, a second flow sensor FT61, and a third flow meter VF61. Flow meter VF61 is again equipped with a capacitive sensor and detects the presence of liquid. Thus, it can be used as a canister empty detection device. Flow sensor FT61, on the other hand, measures a volumetric flow and preferably uses an impeller. First solenoid valve MV71, second flow sensor FT61, and third flow meter VF61 are in turn connected to electronic control unit 44 to provide signals thereto or to be controlled thereby. Downstream of acid dosing unit 86, a valve BV60 is arranged, which in turn is preferably designed as a ball valve and can be controlled by electronic control unit 44.

[0052] In an analogous manner, base dosing unit 88 in this embodiment is designed as a base ejector 89 and is not only supplied with freshwater via fifth line L5, but also with base via an eighth line L8. For this purpose, eighth line L8 is connected to first and second base canister ports 84a, 84b via a valve MV73, preferably a ball valve, and a flow meter VF63. Flow meter VF63 may be identical in design to flow meter VF61. It can also be used as a canister empty detection device. Downstream of base metering device 88, a valve BV62 is arranged, which is preferably formed as a ball valve and is controllable by electronic control unit 44.

[0053] Acid ejector 87, base ejector 89, and sixth line L6 open together into a mixer 90. According to the embodiment shown here, an optional throttle 92 is arranged between sixth line L6 and mixer 90, which is adjustable via an actuator BV61. Actuator BV61 is also controllable by electronic control unit 44. In this way, by controlling valves BV60, BV62 or throttle 92 via actuator BV61, the flow rates of acidified fresh water via fourth line L4, freshwater via sixth line L6 and basified freshwater via fifth line L5 can be mixed together as required. Downstream of mixer 90, a first pH sensor QT61 is arranged to provide a first pH signal to electronic control unit 44. Mixer 90 is connected to acid tank 52 via a ninth line L9 and a further valve BV83, preferably designed as a ball valve. Thus, first pH sensor QT61 can be used to detect the pH of the fluid supplied to acid tank 52 via valve BV83. Alternatively, starting from mixer 90, the liquid can also be supplied to collection tank 50. For this purpose, a valve BV80 is provided, which connects a tenth line L10, which branches off from ninth line L9, to collection tank 50.

[0054] In this way, an aqueous acid solution can be generated in acid tank 52, which can then be used to clean bioreactor 2. To supply the aqueous acid solution from acid tank 52 to bioreactor 2, valve BV83 is closed and valve BV85, which is placed between acid tank 52 and first line L1, is opened. Subsequently, a vacuum can be built up in first line L1 using the pump 46 and the aqueous acid solution can be supplied to bioreactor 2 via valve BV85, first line L1, and supply unit 74 via supply connection 24.

[0055] The aqueous acid solution will then flow through bioreactor 2, more specifically through filter basket 8, and then into liquid tank 5. On this path, the acid of the aqueous acid solution reacts with adhering lime deposits and dissolves them. It is also possible to simultaneously introduce air in the form of bubbles during this process to increase the cleaning effect. This is particularly preferred for lines of bioreactor 2, which can and should also be cleaned.

[0056] Now that the liquid has passed through bioreactor 2, it can be drawn via 1-inch connection 11. This is done using suction unit 74 by means of pump 46.

[0057] The liquid thus drawn from bioreactor 2 can then be fed from the suction unit 72 either directly via the first line L1 and the valve BV85 in turn to the acid tank 52. However, it is also possible to feed the extracted liquid from the suction unit 72 via an eleventh line L11 into third line L3, in the embodiment shown here (FIG. 4) between valve BV78 and flow sensor FT60. If valves BV60, BV62 remain closed, the extracted liquid can be fed through second pH sensor QT60, throttle 92, and first pH sensor 61, then through ninth line L9, valve BV83, and into acid tank 52. In other embodiments, it may also be provided that line L11 opens into third, the sixth, or ninth line L3, L6, L9 at other locations. For example, eleventh line L11 could also open into sixth line L6 downstream of second pH sensor QT60, for example, between throttle 92 and first pH sensor 90. It could also be provided that a further pH is provided in first line L1 to directly measure the pH of the liquid extracted from bioreactor 2.

[0058] As long as the pH value of the extracted liquid passing first pH sensor QT61 falls below a predetermined pH threshold, the aqueous acid solution can be used again to clean bioreactor 2 or another bioreactor. The pH value of the extracted liquid is used here as the acid quality value. Other values can be used as well, such as, in particular, a loading of the liquid with dirt particles or the like.

[0059] If it is determined that the first pH value detected by first pH sensor QT61 exceeds a predetermined pH threshold, the aqueous acid solution in acid tank 52 should be neutralized for subsequent disposal. In order to perform neutralization, the extracted liquid is fed to dosing unit 80 either from suction connection 20 directly, or from acid tank 52 by means of suction unit 72 via eleventh line L11. Here, the aqueous acid solution to be neutralized is fed past flow sensor FT60, second pH sensor QT60, and then divided between fourth, fifth, and sixth lines L4, L5, L6. Here, base is added via the base dosing unit 88 so that the pH value of the aqueous acid solution to be neutralized is increased. The increased pH value can in turn be measured with first QT61 pH sensor. The liquid can then in turn be fed to acid tank 52 or via a twelfth line L12 back to suction unit 72 and from there back to eleventh line L11. The aqueous acid solution is thus neutralized as it circulates within bioreactor cleaning system 1, and in this manner flow neutralization is accomplished. Once a sufficiently high pH has been reached, the liquid is not returned to acid tank 82 via valve BV83, but is returned to collection tank 50 via valve BV80, from where it can be disposed of.

[0060] In addition to acid ejector 87 and base ejector 89, one or more other ejectors could also be provided, for example, to produce blue water mixtures for chemical toilets on trains using bioreactor cleaning system 1.

[0061] FIG. 5 illustrates an ejector which may be used as said acid ejector 87 and base ejector 89. By way of example, FIG. 5 illustrates acid ejector 87, but the same applies to base ejector 89. Acid ejector 87 has a first inlet 92 connected to fourth line L4 and receiving fresh water under pressure. It further has a second inlet 94 connected to seventh line L7 to receive acid. The ejector has an outlet 96 connected to valve BV60 (see FIG. 4). Inside the ejector a nozzle piece 97 is provided, which opens into an interspace 98 in the manner of a venturi pump, so as to draw acid from second inlet 94 and deliver it to a common ejector chamber 99. This common ejector chamber 99 leads to outlet 96 where freshwater and acid are mixed. To accurately dose the acid at second inlet 94, valve MV71 can be opened in a pulsed manner to adjust the pH of the mixed liquid at outlet 96 as accurately as possible.

[0062] FIG. 6 schematically illustrates the circuit of the flow-through neutralization. P indicates either the pump 46 or the freshwater connection 42 Important is that the circuit is set in motion. From there, the liquid then reaches first flow meter FT60, pressure sensor PT60 and second pH sensor QT60. The line branches on the one hand into line L6 and line L5, which leads to base ejector 89, more precisely to first inlet 92. Valve MV73 is connected to second inlet 94, via which base can be fed to second inlet 94 in the embodiment shown in FIG. 6. Dosing can then be further adjusted via valve BV62, while in sixth line L6 the other path can be regulated via throttle 92 and valve BV61.

[0063] In mixer 90, in which sixth line L6 and fifth line L5 as well as fourth line L4 (cf. FIG. 4) are combined, a diffuser 100 is also provided in the embodiment shown here. This is shown here only schematically and can be designed, for example, as a static mixer with various mixing elements. Downstream of diffuser 100, first pH sensor QT61 is provided. This circulation is carried out until a sufficiently high pH value has been reached in acid tank 52 to allow the aqueous solution to be disposed of.

[0064] FIG. 7 now illustrates a characteristic curve of a neutralization of an aqueous acid solution. The pH value is plotted on the ordinate and the amount of base added on the abscissa. As can easily be seen from this graph, the pH value initially rises only slightly, even with a substantial amount added, in a first section up to about pH 2, then very sharply, up to a little pH 11/12, and then flattens out again. The neutral range between 6.5 and 9 is marked here with a background and the target pH value ZpH is also located here. The aqueous solution should be in this range in order to be disposed of. This graph illustrates why it is difficult to bring about neutralization in a stationary process within acid tank 52. In continuous neutralization, as proposed in the present invention, the neutral range between 6.5 and 9 pH can be gradually adjusted by the closed loop control system without provoking “overshoot.” The diagram also shows the pH threshold SpH, which is used to measure whether or not the aqueous acid solution in acid tank 52 can continue to be used for purification. If it is determined that the aqueous solution in the acid tank 52 exceeds the pH threshold SpH, the neutralization process is initiated. In a range 102, the solution is no longer usable for cleaning, but it is also not yet neutral enough to be disposed of.