Patent Application
20180164769
This application claims the benefit of priority under 35 U.S.C. 119 to United Kingdom Application No. GB1620903.3, filed on Dec. 8, 2016, the entire contents of which are herein expressly incorporated by reference.
The present invention relates to food waste management system, and in particular, a telematics control system for a food waste management system.
The use of renewable energy and the development and adoption of associated green technologies is ever-increasing. One renewable energy source, bio methane, is a product of biogas. Biogas is usually produced by anaerobic digestion plants, which process organic waste, such as food and livestock waste. In an anaerobic digestion plant, microorganisms break down organic material (otherwise known as feedstock) to form bio methane and organic fertilizer. Naturally, the continued production of biogas relies on the ongoing supply of organic waste. Furthermore, the production of biogas is maximised when the calorific content of the food waste stock is optimised to be as high as possible.
Many businesses dealing with food generate unavoidable food waste. Such waste could be, and sometimes is, directed to anaerobic digestion plants. To encourage businesses to manage their organic waste for renewable energy purposes (rather than sending it to landfill or incineration), systems exist which allow businesses to manage the processing of their organic waste before it is delivered to an anaerobic digestion site. It is an aim of the present invention to improve the efficiencies of current systems and processes for producing feedstock for biogas production.
According to a first aspect of the invention, there is provided waste management apparatus comprising means for receiving and storing organic waste, processing means configured to process the organic waste into feedstock, and a processor in communication with the processing means, wherein the processor is configured to determine values of one or more properties of the feedstock using the processing means, determine one or more new operational parameters of the processing means based on the determined values of the one or more properties of the feedstock, and output instructions to the processing means, wherein the instructions are based on the determined one or more new operational parameters. Advantageously, monitoring of the feedstock and adjusting the operation of the apparatus accordingly results in efficient feedstock generation and improved feedstock quality.
According to a second aspect of the invention, there is provided a method for controlling operation of waste management apparatus, comprising calculating a value of a parameter of the organic waste in the waste management apparatus, comparing the calculated value with stored data pertaining to the parameter of the waste; determining values for one or more operational parameters of the waste management apparatus based on the comparison, generating instructions based on the determined values for one or more operational parameters of the waste management apparatus; and outputting the instructions to the waste management apparatus.
Organic waste management apparatus is apparatus for receiving organic waste, processing the waste to generate ‘feedstock’, monitoring the feedstock and storing the feedstock until the feedstock is extracted from the apparatus and delivered to a bio digestion facility. The main components of an exemplary organic waste management system are shown in
The system of
When storage tank 102 is full and the food waste has been sufficiently processed into feedstock which is optimal for biogas production (as will be discussed in further detail below), storage tank 102 is emptied via collection outlet 106. A control unit 107 located within the unit 100 is configured to monitor, using data from sensors located in storage tank 102, parameters of the feedstock (e.g. its viscosity, volume, specific gravity) and is in communication with a remote management system 109. A user interface 108 is configured to output user instructions, warning messages, etc., as instructed by control unit 107.
Although not shown in
An overview of a waste management process 200 is shown in
The system of
Vacuum sensor 301 is typically a PM 2655 programmable electronic pressure sensor with a range of −0.99 to 4.00 bar (−14.4 to 58.0 PSI). The pressure inside storage tank 102 is chosen to be lower than atmospheric pressure and sufficient to pull waste through hopper 101 and macerator 103. Vacuum sensor 301 is configured to sense changes to the pressure that are sufficient to jeopardise effective operation to pull waste through hopper 101. The determination is sent to the module 306, and, if necessary, the vacuum pump 105 is operated to compensate for a change in pressure and thus maintain a desired pressure.
Level sensor 302 monitors the level (height) of the feedstock within the tank so that it can be determined whether the tank is full. Level sensor 302 may be a RM900 multiturn solid shaft encoder having a resolution of 24 bits/4096 steps per revolution. The temperature of the feedstock is measured by temperature sensor 303 which is preferably a TA 3131 temperature transmitter sensor (−50 to 150 deg C.) with an analogue output of 4-20 milliamps. The temperature of the feedstock is a useful indicator of the extent to which it has been processed and therefore its maturity.
Pressure sensor 304 is typically a PT5404 electronic sensor with a measuring range of 0-10 bar. Valves within unit 100 are air valves and therefore need to be maintained at an operational pressure. If pressure sensor 304 detects a deviation from operational pressure, a compressor (not shown) can be used maintain the pressure required to effective operation of the valves.
Door sensor 305 senses whether the door of hopper 101 is properly shut and is typically a SI18-DC8 PNP NO proximity door sensor having a switching distance of 8 mm. If sensor 305 determines that the door to hopper 101 is not properly shut, a routine wash cycle to wash hopper 101 and macerator 103 (using pressurized water) will be delayed until sensor 305 determines that door is properly closed. Weight sensor 317 is preferably a strain gauge load cell and SEM 1600B amplifier and measures the weight of the feedstock in the storage tank 102. The weight of the feedstock is used by the PLC 311 to measure its specific gravity.
Module 306 generally acts as a node to manage the sending of data from the sensors to the PLC 311 and the receipt of instructions from the PLC 311 relating to operation of inverters 307-310. Typically module 306 is a CAN node CR2016, I/O module digital and analogue CAN interface with configurable input/output functions. Level and temperature sensors 302, 303 are configured to take readings periodically (discussed below) and immediately send the readings to module 306 which in turn passes them to PLC 311. Readings from weight sensor 317 are sent directly to PLC 311. The vacuum, pressure and door sensors 301, 304 and 305 are configured to sense a change in default operating conditions of their respective components and as such take readings far more frequently than other sensors.
Based on instructions from PLC 311 (which may derive from readings from sensors 301-305), module 306 can instruct a change in default operation of jetting inverter 307, macerator inverter 308, hydrolyser inverter 309 and vacuum pump inverter 310. For example, if it is determined that a user is attempting to open the door to hopper 101 during a wash cycle, jetting inverter 307 (which controls output of pressurized water) can be controlled accordingly. Macerator inverter 308 controls the driving power of macerator 103. Detection of a significant change in power usage by macerator inverter 308 may indicate that macerator 103 is malfunctioning and needs to be switched off to facilitate servicing.
PLC 311 (also located within telematics unit 107) is typically a CR0020 PLC which can program 40 inputs/outputs with configurable functions. An RS232 PC interface 312 allows for a laptop, for example, to be connected to the PLC 311. This facilitates the copying of historical data relating to operation of unit 100 to the laptop such that the data can be analysed by an engineer (for example) for diagnostic purposes, performance analysis review and the like.
PLC 311 is the processing hub of control module 107. It is configured to analyse the data received from sensors 301-305, 317 and issue output instructions based on the analysis. If the data received from door, vacuum or pressure sensors 305, 301, 304 indicate a fault (for example, that the door of the storage tank was not closed securely after a recent maintenance visit, or that the vacuum pump is faulty such that food is not been drawn into storage tank 102 from hopper 101) the PLC will control operation of the unit 100 accordingly (for example, by powering off various components, outputting instructions or warning messages to user interface 108 and/or issuing alert messages to remote system 318 to schedule a maintenance visit (for example, if wash water is below a predetermined level and requires filling) or remote diagnostics connection).
PLC 311 is further configured to analyse readings from weight, level and temperature sensors 317, 302, 303 and output instructions to hydrolyser inverter 309 based on the analysis. PLC 311 is configured to periodically calculate values of viscosity and specific gravity of the feedstock using the received sensor data and data from the hydrolyser inverter 309, and compare the calculated viscosity value with those in a stored look up table. The look up table comprises a list of values for viscosity and hydrolyser frequency and speed, and is compiled (at least initially) using computational fluid dynamics. Thus, the provision of hydrolyser operational parameters for a particular value range of viscosity is calculated using predictive modelling for how the viscosity will change with hydrolyser speed as the storage tank 102 fills up with feedstock (wherein parameters such as the type of waste that will be input and the frequency at which food will be provided to the unit 100 is based on the location and predicted usage of a specific unit 100). Accordingly, whilst the values in look up table are specific to each unit 100, they are based on a priori estimates. For example, a consultation with a user of unit 100 prior to first use of unit 100 by the user may indicate how often, how much, and what type of food waste will be input to the particular unit 100. This information allows remote system 318 to determine, in conjunction with known information concerning the optimisation of the quality of feedstock generally, desired values for viscosity over the course of a cycle to yield optimal feedstock which will produce the most biogas. This information in turn also determines the initial default operation of the hydrolyser inverter. However, over time, as the unit is used, the remote system 318 is able to build up a more accurate description of how a particular unit 100 is being used, which of course may differ from that as originally predicted. Remote system 318 can then adjust values in the look up table such that processing of the feedstock over time, by virtue of the operation of the hydrolyser 104, is optimised.
Based on historic data relating to a particular unit 100, remote system 318 is also able to predict when storage tank 102 of unit 100 will require emptying. For example, if the previous three empty-to-full cycles each took between 9 and 11 days, the remote system 318 schedules emptying of unit 100 in 10 days from the date storage tank 102 was previously emptied. As discussed above, the PLC 311 of unit 100 is configured to output an alert message to the remote system 318 should the storage tank 102 approach full and require emptying outside of the scheduled dates/times.
As will be discussed in further detail below, the power used by hydrolyser inverter to drive hydrolyser 104 at a known frequency/speed is measured to determine a value of the viscosity of the feedstock using a viscometer. This viscosity value is looked up in the look up value to identify the desired operational characteristics, including frequency of rotation and frequency and duration of operation for the hydrolyser 104. Operation of the hydrolyser 104 is then adjusted accordingly. Once PLC 311 determines, using the look up table, that the feedstock is of optimal quality (i.e. its viscosity has reached the desired value), it can issue an alert to indicate that the storage tank 102 should be emptied, regardless of whether or not the storage tank 102 is full or near-full.
To aid the breakdown of organic waste, water may be introduced into macerator 103, the amount of water depending upon the quantity and type of organic waste. Knowledge of the specific gravity of the feedstock is required in order to determine whether the feedstock can and should be emptied and transported to an aerobic digestion facility. If the specific gravity of the feedstock is too high, for example, the feedstock is too dense to be effectively extracted from storage tank 102. Accordingly, although the viscosity of the feedstock (and its level in the tank) is the primary factor for determining when storage tank 102 should be emptied, the specific gravity of the feedstock is a secondary factor.
In addition to managing the data received from the sensors 301-305, 317 and received from remote system 318, algorithms of the PLC 311 also monitor, control and log the process by which waste is input to and unloaded from the tank. It outputs instructions to the user interface 108 to guide a user through the waste input process and to guide waste collection personnel through the emptying process. Furthermore, the PLC 311 stores data relating to the number of loading operations, number of times the unit has been emptied, the changes in the operation of the machine over time, the particular users of the machine etc., which data is also sent to the remote system 318 for subsequent customer reporting.
Remote system 318 undertakes a variety of functions including storing and collating calculations of values of parameters of feedstock of multiple different units 100, analysing data received from single and multiple units 100, sending firmware upgrades to individual units 100, producing reports for customers/users of unit 100, outputting instructions concerning maintenance and feedstock collection to an organisation responsible for maintenance and/or collection, facilitating remote connection to individual units 100 for remote diagnostic purposes and outputting control instructions to individual units 100 (which may override the instructions of PLC 311, as will be described in further detail below). Some or all functions of remote system 318 may be performed on cloud-based servers.
By collectively analysing the values of viscosity and specific gravity of feedstock received from the PLCs of multiple units 100, remote system is able to intelligently use this information to adjust the operational parameters of an individual unit 100.
Referring again to
An overview of the data collection process will now be described with reference to
Step 401 denotes a number of initial automated checks that are made by the PLC 311 of unit 100. Such initial checks typically include checking whether or not unit 100 is in sleep mode (i.e. not hydrolysing the contents of storage tank 102), checking whether organic waste is currently being loaded into hopper 101, checking whether storage tank 102 is currently being emptied, and checking whether a washing cycle is currently in progress. If the initial checks are satisfied, the process moves to step 402 whereby the vacuum sensor 301 determines whether or not there is a deviation from the system pressure that may require compensation by vacuum pump 105. Assuming the system vacuum has not collapsed, pressure sensor 304 determines the air pressure for system values at step 403.
At step 404, the weight of the feedstock is measured and at step 405 the height level of the feedstock in storage tank 102 is measured. Once the vacuum, pressure, weight and level sensor readings have been collected and sent to the PLC 311, the PLC 311 instructs the hydrolyser to run at a predetermined frequency for 60 seconds. This is done so that the torque exerted by the hydrolyser can be calculated by the hydrolyser inverter (steps 406 and 407). At step 408, the temperature of the feedstock is determined. At step 409, the PLC 311 uses the determined torque to calculate the viscosity of the feedstock. As the feedstock becomes more viscous, the hydrolyser inverter will be required to supply a greater current to maintain a speed of the hydrolyser, thereby resulting in higher torque output from its motor. The specific gravity of the feedstock is calculated by the PLC 311 using the level and weight readings. Specific gravity is an indicator of the solid content within the feedstock. As mentioned above, a value of specific gravity above a predetermined amount indicates that there may be difficulty in emptying the feedstock. If the calculated values of the parameters of the feedstock indicate that the quality of the feedstock is optimal, the remote system 318 is alerted.
The frequency at which the hydrolyser 104 of a particular unit 100 will be driven will depend on the type and quantity of organic waste input into unit 100. For example, if waste is input infrequently, hydrolyser 104 may need only rotate at a frequency of 60 rpm for a period of 1 minute every hour in order to effectively process the feedstock such that the viscosity of the feedstock is optimal when storage tank 102 is full or near full. Operating hydrolyser 104 more frequently than this may consume unnecessary power. For a different unit 100 having different usage characteristics, the duration and frequency for which the hydrolyser runs and the frequency at which it is rotated may be different.
Accordingly, once the PLC has determined the viscosity of the feedstock as a result of the data collection process, the PLC 311 compares the calculated values of viscosity with a look up table (as discussed above) to determine new operational parameters of hydrolyser 104 to optimise feedstock quality. Alternatively or additionally, remote system 318, having received the viscosity and specific gravity values of the feedstock, compares the viscosity values to a large data set relating to multiple waste management units and determines new operational parameters for hydrolyser 104 accordingly (as discussed above). When the remote system 318 does determine new operational parameters, and such determination coincides with a determination made by PLC 311, the associated instructions sent to the PLC 311 from remote system 318 may override those generated by the PLC 311 itself
The PLC of unit 100, having received instructions from remote system 318 or those it has calculated, controls the inverter of hydrolyser 104 such that the hydrolyser will run at the specific speed and frequency, until newer instructions instructing a change of the current hydrolyser operational parameters are received.
| Number | Date | Country | Kind |
|---|---|---|---|
| 1620903.3 | Dec 2016 | GB | national |
