Method for monitoring a cleaning cycle for cleaning a mechanical separation device

Abstract

A method for monitoring a cleaning cycle for cleaning a mechanical separation device comprising the following steps A Provision (101) of a mechanical separation device (1), in particular a centrifuge or a filtration device; B. Feeding (102) a first cleaning medium comprising a cleaning additive into the device of the mechanical separation technology (1), wherein the feeding takes place in a defined cleaning time interval and C Determining (103) a value of the cleaning medium passed through the device that correlates with the redox potential, taking into account the pH value of the cleaning medium passed through; wherein the determined value is compared with a predetermined target value and, if the target value is exceeded or fallen below, the supply of the cleaning medium is interrupted (105) before the end of the cleaning time interval and / or the first cleaning medium and / or a sequence of further cleaning media is adjusted.

Description

[0001] The present invention relates to a method for monitoring a cleaning cycle for cleaning a mechanical separation device, such as centrifuges, like centrifugal separators or decanter centrifuges, or filtration devices, like membrane filtration systems and / or cross-flow filtration systems. Preferably, the cleaning cycle is designed as a CIP cleaning process.

[0002] Process plants are known to be cleaned using CIP (cleaning in place). While conventional process plants are generally subject to constant contamination, mechanical separation equipment has varying cleaning requirements depending on the separation task. For example, separation and clarification processes in the pharmaceutical industry demand high cleaning standards. The cleaning media and additives used are correspondingly aggressive. Conversely, other applications, such as wastewater treatment, have lower cleaning requirements. Here, minimizing waste of cleaning media is desirable. Therefore, a CIP cleaning process must be designed to be as flexible as possible to meet these diverse cleaning requirements.However, in most cases, the cleaning additives are overdosed in CIP cleaning media, and the cleaning medium is discarded after a single cleaning cycle or after only a few cleaning cycles.

[0003] Therefore, for the different requirement profiles of CIP cleaning in mechanical separation devices, no sufficient solutions are currently offered for the resource-saving use of cleaning media for different types of soiling.

[0004] The present invention solves this problem by providing a method with the features of claim 1.

[0005] This provides a method for monitoring a cleaning cycle for cleaning a mechanical separation device. If the cleaning medium is insufficiently concentrated, the monitoring allows the CIP cleaning cycle to be aborted and restarted with a more concentrated cleaning medium. Conversely, the cleaning medium can be used until this point of insufficient cleaning is reached, which is particularly resource-efficient.

[0006] The measured variable is a value directly correlated with the redox potential. This could be, for example, the redox potential. This is defined according to DIN 38404-6 and can be determined using a redox sensor – also called an ORP sensor. This is advantageous because the cleaning effect of the majority of cleaning media can be attributed to an oxidative effect. The measurement, especially in combination with the pH value, conductivity, and, if applicable, the medium temperature, allows for a reliable assessment of the cleaning effect of the cleaning medium after each pass through the mechanical separation system.

[0007] As an alternative to switching off when cleaning media is depleted, the cleaning medium can also be adapted, e.g. by adding cleaning additives such as acids, bases or oxidizing agents, or possibly also reducing agents.

[0008] The sequence of subsequent cleaning media can also be modified based on the redox potential determination. For example, a rinse cycle with water can be performed after the cleaning medium is introduced. Depending on the aggressiveness and concentration of the cleaning medium, this rinse cycle can be longer or shorter, or carried out with a lower or higher flow rate. A leveling and / or neutralizing agent for the cleaning medium can also be added and adjusted, particularly before the rinse cycle.

[0009] Specifically, the cleaning cycle includes at least the following steps: A Provision of a mechanical separation device, in particular a centrifuge or a filtration device; These devices may, in addition to all other components of a process plant, have a separate cleaning unit due to the increased cleaning requirements. B. Feeding a first cleaning medium through the device of the mechanical separation technology, wherein the feeding takes place over a defined cleaning time interval and The cleaning time interval can be reset for each cleaning cycle. This can also be done based on the value determined in step C. C Determining a value of the cleaning medium passed through the device that correlates with the redox potential, taking into account the pH value of the cleaning medium passed through.

[0010] The value is preferably determined by measurement. Advantageously, the cleaning medium comprises a solvent, such as water, and one or more cleaning additives, such as an oxidizing agent or a highly concentrated alkali. However, a corresponding value can also be calculated from measured values. A redox sensor – also called an ORP sensor – is preferably used for this determination. A value proportional to or identical with the redox potential can be used as the correlating value. A redox potential or a specific standard potential of a component, such as chlorine, can be determined if chlorine is a component of the cleaning medium.

[0011] The measured value is compared to a predefined target value. If the value exceeds or falls below the target value, the supply is interrupted or the concentration of the cleaning medium is adjusted before the end of the cleaning interval. Interruption and adjustment are particularly useful with short cleaning intervals and long response times from the measurement and evaluation system. In such cases, the system is too slow to achieve real-time adjustment of the cleaning medium, including the necessary hydration of the added cleaning additive and homogeneous mixing.

[0012] Alternatively or additionally, as discussed previously, the first cleaning medium can be adjusted, for example, regarding the concentration of one or more cleaning additives. Especially with longer cleaning cycles, there is sufficient time to make such an adjustment. Furthermore, the sequence of subsequent cleaning media, such as a rinsing medium or a neutralizing medium, can also be adjusted, either alternatively or additionally.

[0013] Overall, the process offers exceptional flexibility, enabling it to be used in a wide range of applications, such as separation tasks, with varying cleaning requirements, while allowing for resource-efficient use of a cleaning medium.

[0014] Advantageous embodiments of the invention are the subject of the dependent claims.

[0015] It is advantageous if the procedure includes a step D, which involves providing a new cleaning medium with a different concentration of a cleaning additive compared to the first cleaning medium, and repeating steps B and C using this new cleaning medium. The concentration of the cleaning additive chosen in step D can also be changed to zero, using a completely different cleaning medium. Subsequently, the introduction of the cleaning agent in step B and the measurement in step C can be repeated with this new or modified cleaning medium.

[0016] The mechanical separation device can also be connected to a cleaning unit for supplying the cleaning medium, with the cleaning medium generated during the cleaning process being returned to the cleaning unit. Within the cleaning unit, the used cleaning medium can be adjusted in a resource-efficient manner.

[0017] The mechanical separation device can advantageously have an inlet and a first outlet, wherein the device includes a closed loop for returning the collected cleaning medium from the first outlet to the inlet, and the method particularly preferably includes direct return from the first outlet to the inlet. The closed loop allows for multiple rinsing cycles, e.g., as part of a cleaning sequence such as cleaning, rinsing, cleaning, and rinsing again. Rinse water, for example, can also be used as the cleaning medium in the closed loop.

[0018] The procedure can include adjusting the cleaning interval based on the value determined in step C. If the cleaning effect is insufficient, the cleaning interval can be extended. Conversely, the cleaning interval can be iteratively shortened to achieve optimal cleaning in the shortest possible time. Ideally, all measurement data should be acquired near the redox sensor to avoid system-related fluctuations.

[0019] Furthermore, determining a value of the cleaning medium passed through the separation apparatus in step C that correlates with the redox potential can be carried out taking into account the conductivity and / or temperature of the cleaning medium. This allows deviations from standard conditions to be compensated for.

[0020] Advantageously, and also optionally, pressure measurement can be used to compensate for deviations from standard conditions, preferably near the redox sensor or at least in the same line of the mechanical separation device as the redox sensor. Suitable pressure sensors are commercially available from a variety of manufacturers for use in plant engineering.

[0021] It is advantageous to assess the cleaning capacity of the cleaning medium based on the value determined in step C. Depending on the measured redox potential, the remaining oxidizing power for further or repeated use of the cleaning medium can be determined. This allows the user to easily monitor the quality of the cleaning and the cleaning medium.

[0022] Furthermore, based on the value determined in step C, the concentration of one or more cleaning additives in the cleaning medium can be advantageously adjusted. Alternatively or additionally, a cleaning medium can be selected from a number of different cleaning media.

[0023] Based on the value determined in step C, it is advantageous to select a water quality from the water contained in the cleaning medium.

[0024] The mechanical separation device and / or the associated cleaning unit may include a control and / or evaluation unit for evaluating the measured values ​​recorded by a redox measuring device and determining a value from the measured values ​​according to step C.

[0025] The cleaning cycle can be preferably designed as a CIP cleaning cycle as part of a CIP cleaning process.

[0026] In step C, the flow rate and / or the duration of the supply of the first or subsequent cleaning media can also be adjusted based on the determined value.

[0027] The adjustment of the first cleaning medium can preferably be based on the value determined in step C, either by adjusting the concentration of the cleaning additive in the cleaning medium, and / or by adjusting a sequence of further cleaning media, preferably the flow rate and / or the duration of a rinsing water phase supplied after the cleaning medium has passed through. This can be done in real time, so that the adjustment is immediate and has a fast response time.

[0028] The purification cycle can be carried out after the recovery of a product or intermediate product as a product phase resulting from a separation process in the food, pharmaceutical or chemical industries.

[0029] Based on the value determined in step C, the control and / or evaluation unit can issue a control command to a control element to adjust the concentration of the cleaning additive in the cleaning medium, preferably an acid, base, and / or an oxidizing agent. Alternatively or additionally, the control element can adjust the temperature of the cleaning medium, the flow rate of the cleaning medium, and / or the rinsing times and / or the flow rate of a rinsing medium supplied to the mechanical separation device after the cleaning medium.

[0030] The redox measuring device used in the process can be used, in particular, to determine the purification properties of a liquid in technical installations, and the device is preferably capable of measuring redox values ​​in mV. In addition to measuring pH and conductivity, the measuring device can also be used to measure and determine the redox potential.

[0031] The measuring device can be integrated into a CIP system and enable automatic adjustments of CIP parameters such as concentrations, temperature, flow, valve settings and rinsing times after CIP based on the measured and / or determined redox values.

[0032] The measuring device can advantageously trigger warnings or alarms if certain conditions are not met, or directly make changes to critical operating parameters.

[0033] The device can be used, with appropriate evaluation algorithms, to further adjust the entire cleaning process at a specific location, with a specific unit, or with a specific type of contamination.

[0034] The method according to the invention can also include steps for integrating the measuring device into existing CIP systems and for training personnel in the interpretation and application of the ORP measurement values.

[0035] By determining the redox potential and providing a redox measuring device in combination with a mechanical separation device, which serves as an additional measurement for determining the cleaning capabilities of a liquid, it becomes possible to measure redox potentials as voltage values ​​in mV, where positive values ​​indicate reductive and negative values ​​indicate corrosive or oxidative properties. Integration into the control system of the entire CIP system ensures correct concentration, contact time, and return to a neutral state after rinsing, and achieves automatically reproducible results.

[0036] Furthermore, the invention offers improved quality control of the cleaning process and increases safety before the release of a production unit after cleaning.

[0037] The present invention will be explained in more detail with reference to an exemplary embodiment and the following figures. These show: Fig. 1. Schematic representation of a mechanical separation device and a cleaning system connected to it; and Fig. 2 Process diagram illustrating the course of a method according to the invention.

[0038] Mechanical separation equipment, such as centrifuges or filtration systems, can be subject to very high levels of contamination depending on the separation task. Especially when processing media with frequently changing compositions, frequent cleaning is necessary to ensure clean separation and / or clarification.

[0039] An example of a medium with frequently changing composition is fruit juice production, in which fruit of different varieties, origins, and qualities is processed simultaneously. For instance, the turbidity of the starting material is subject to increased fluctuations due to the aforementioned parameters.

[0040] Cleaning mechanical separation equipment, particularly in the food, pharmaceutical, and chemical industries, therefore requires efficient and reliable methods for cleaning production facilities between production runs. This often involves the so-called cleaning in place (CIP) process, an automated cleaning method that requires no disassembly of the equipment components. Until now, monitoring and control of the cleaning processes have been achieved by measuring the pH value and electrical conductivity of the cleaning medium. However, these parameters only provide indirect information about the actual cleaning capacity or aggressiveness of the cleaning medium.Particularly when using different water qualities and cleaning concentrates to provide the cleaning medium, the significance of these measurements can vary greatly, as the interactions between the components of the water and the added chemicals are complex and cannot be captured solely by conductivity and pH value.

[0041] Depending on the starting material, the degree of contamination in the mechanical separation equipment can vary after each production cycle, as explained previously. In contrast, the CIP cleaning processes known to date often operate periodically with a constant repetition interval and a defined cleaning time interval within which the cleaning is carried out.

[0042] Ideally, the cleaning medium should be tailored to the cleaning task, i.e., the scope of cleaning should depend on the extent and type of contamination. Precise dosing of potentially aggressive cleaning additives reduces disposal costs and protects the device material compared to overdosing. However, to achieve sufficient cleaning effectiveness with precise dosing, process monitoring measures must be implemented. This is where the invention comes in.

[0043] Fig. Figure 1 represents a device for mechanical separation technology. The mechanical separation process carried out with the device can, in particular, exploit density differences. This includes, in particular, centrifugation processes. Corresponding devices are, for example, centrifugal separators and / or decanters. Another mechanical separation process separates components according to particle size. This can involve filtration processes, such as membrane filtration or cross-flow filtration.

[0044] Overall, the mechanical separation device 1 is intended to separate a solid-liquid and / or a liquid-liquid mixture into several phases. The process is explained in more detail below, primarily using a centrifugal separator 1a with a rotatable and preferably vertically mounted drum.

[0045] Separator 1a has an inlet 2, a first outlet 3, and a second outlet 4. The inlet 2 and the first outlet 3 are part of a circular line 5, which allows recirculation of the discharged liquid into separator 1a.

[0046] The described process illustrates the cleaning mode of a separator, particularly within the context of CIP cleaning. Normal operation, in which clarification of a liquid phase and / or liquid-liquid separation takes place, is known.

[0047] The inlet 2 and in particular the circuit line 5 are connected to a CIP cleaning unit 6 (cleaning in place).

[0048] The cleaning unit 6 includes a tank 7 for a cleaning medium and a pump 8 for conveying the cleaning medium into the separator 1a.

[0049] The cleaning unit 6 is connected to the circuit 5 via a supply line 9 and a return line 10. The supply line 9 has a flow meter 11.

[0050] Furthermore, the drain line 10 has a redox measuring device 12 of the cleaning medium after it has been discharged from the separator 1a.

[0051] The second outlet 4 can be designed as a disposal line for draining the cleaning medium from the separator 1a.

[0052] Tank 7 of the cleaning unit includes a first supply line 13 for an acid, a second supply line 14 for an alkali and a third supply line 15 for water.

[0053] Fig. Figure 2 shows a process flow diagram for controlling the cleaning process in the device for mechanical separation technology 1.

[0054] In a first step 101, the device for mechanical separation technology 1 with a cleaning unit 6 connected to it is provided.

[0055] In a second step 102, a cleaning medium is passed through the mechanical separation device 1 and then through the cleaning unit 6. Within the scope of the present invention, the cleaning medium is preferably understood to be an aqueous solution with one or more cleaning additives. This cleaning additive can preferably be selected from the group consisting of an acid, a base, an oxidizing agent, and / or a disinfectant.

[0056] In addition to the cleaning medium, a rinsing medium, in particular water, can be added to separator 1a after the cleaning medium as part of the cleaning sequence.

[0057] Water, acid, and / or alkali can also be introduced into the mechanical separation device, usually sequentially, in a so-called cleaning sequence. It is also possible to premix a cleaning medium, preferably a multi-component cleaning fluid, in tank 7.

[0058] It is also possible to add an oxidizing agent to the water in order to determine the redox potential of the cleaning fluid. CIP cleaning is carried out by feeding a specific volume of cleaning fluid into the mechanical separation device 1 within a predefined time interval.

[0059] During cleaning, contaminants in tank 7 are dissolved. The redox potential of the cleaning medium changes during cleaning.

[0060] In a third step 103, the redox potential is determined, e.g., by measuring a redox voltage using the redox measuring device 12.

[0061] In a fourth step 104, the measured values ​​are evaluated by comparing the actual value with the target value.

[0062] If the redox potential of the cleaning medium exceeds or falls below a predetermined setpoint, the supply of the cleaning medium is interrupted. Then, optionally, the cleaning can be restarted with a new time interval according to steps 102 and 103; otherwise, the CIP cleaning continues until the end of the cleaning time interval.

[0063] In another embodiment of the process, after the interruption, the already used cleaning medium 106 can be returned to tank 7 and the concentrations of the components readjusted. For example, additional oxidizing agent can be added. This is a particularly environmentally friendly variant, in which only a small amount of waste liquid is produced.

[0064] Alternatively, in a second scenario, if the supply of cleaning media is interrupted, the residual liquid in separator 1a can be drained via the second outlet 4. New, unused cleaning fluid, stored in tank 7, is then added to separator 1a. This option is advantageous when cleaning requirements are particularly stringent.

[0065] Alternatively or in addition to interrupting the supply line, the cleaning medium can also be adjusted, e.g., in real time. This can be achieved by adjusting the flow rate and / or by adjusting the concentration of the cleaning medium.

[0066] Alternatively or additionally, the sequence of other cleaning media, e.g., a rinsing fluid or a cleaning medium with further or different cleaning additives, can also be adjusted.

[0067] Through redox monitoring, the cleaning capability 107 of a CIP cleaning medium can be determined within the scope of the present invention.

[0068] By implementing redox potential (ORP) measurement in combination with traditional measurement methods such as pH and conductivity, the present method according to the invention enables optimal cleaning with minimal consumption and multiple uses of the CIP medium. The ORP measurement provides, among other things, additional information about the oxidative and reductive properties of the cleaning medium, which are crucial for effective cleaning. This monitoring makes it possible to precisely adjust the cleaning parameters and the CIP cleaning cycle to achieve optimal cleaning results while simultaneously ensuring material compatibility and the safety of the equipment.

[0069] For this purpose, the device of Fig.1. Advantageously, the system can be supplemented by a conductivity meter 16, a pH meter 17, and a temperature sensor 18. A pressure sensor (not shown) can also be positioned in the vicinity of the aforementioned measuring devices. To determine the redox potential, the pH and conductivity measurements can be combined with the redox measurement values. The same applies to the temperature and pressure.

[0070] Implementing redox measurement to monitor CIP cleaning overcomes the limitations of pH or conductivity meters. Redox measurement provides additional information about a liquid's cleaning capabilities and its neutral state after rinsing. Integration into the control system allows for recording the actual cleaning capacity of a cleaning medium and its neutral state after rinsing, improving the overall cleaning process quality and providing greater safety before the system is released for production.

[0071] The cleaning ability of the CIP cleaning fluid is adjusted during the process by the metered addition of either a basic, an acidic chemical or even a disinfectant, in particular an oxidizing agent.

[0072] Redox measurement allows for the determination of the cleaning capacity of the CIP cleaning fluid after it has passed through a mechanical separation device. This provides insights into the reusability of the cleaning fluid and the extent or degree of cleaning. If the cleaning is insufficient, the CIP cleaning process can be repeated with new or reprocessed CIP cleaning fluid. The redox meter can transmit measurement data, along with time-correlated pH values, to a control and / or evaluation unit for the CIP cleaning process. This ensures correct concentrations of cleaning additives and contact times or cleaning intervals, and allows the fluid to return to a neutral state after rinsing.

[0073] Furthermore, the measured values ​​can also be used to warn or alarm in case of non-compliance with certain conditions or to adjust CIP parameters such as concentrations, temperature, flow rate, valve settings and rinsing times after CIP. Reference sign 1 Device for mechanical separation technology 1a Separator 2 Inlet 3 Procedure 4 Procedure 5 District Management 6 CIP cleaning units 7 Tank 8 pump 9 Supply line 10 Return line 11 Flow meter 12 Redox meter 13 Supply line 14 Supply line 15 Supply line 16 Conductivity meter 17 pH meter 18 Temperature sensor 101 Provision of the mechanical separation equipment 102 Passing a cleaning medium through 103 Determination of the redox potential 104 Evaluation of the determined values 105 Interruption of the supply line 106 Recycling of cleaning medium 107 Determination of cleanability

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