Digester Foam Detection via Dual Pressure Sensors
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Solution Overview
Problem
Existing digesters face challenges in detecting and managing foam that forms above the intended level of biomass and/or sludge, leading to undesired conditions that can disrupt the digestion process.
Innovation Solution
The use of two pressure sensors, one connected to the upper part and another above the intended level, with a tube inlet just above the intended level, allows for the detection of foam by measuring pressure differences, and optional anti-foaming agent application or foam outlet to manage excess foam, ensuring accurate pressure readings and preventing foam interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single pressure sensor is used to measure pressure in the digester, then the device complexity is reduced, but the measurement precision of foam detection deteriorates
Solution Approach 1:
The pressure measurement function is segmented into two separate sensors positioned at different heights (first sensor at upper part, second sensor just above intended level). Each sensor measures pressure at its specific location, and the difference between these segmented measurements enables accurate foam detection while maintaining manageable device complexity
Solution Approach 2:
The solution transitions from a single-point pressure measurement to a multi-dimensional approach by positioning sensors at different vertical levels within the digester. This spatial dimensionality allows the system to detect foam formation by comparing pressure gradients across different heights, improving measurement precision without excessive complexity increase
2Difficulty of detecting and measuring
If the second pressure sensor is positioned high above the intended level, then foam detection capability is improved, but the reliability of pressure readings deteriorates due to foam interference
Solution Approach 1:
The second pressure sensor is positioned at a specific local position just above the intended level (not too high), creating an optimal measurement zone where foam presence can be detected through pressure differential without the sensor being directly contaminated by foam. This localized positioning maintains both detection capability and reading reliability
Solution Approach 2:
The pressure differential between the two sensors acts as an intermediary indicator of foam presence. Rather than directly measuring foam, the system uses the intermediate parameter of pressure difference to indirectly detect foam formation, maintaining reliability while improving detection capability
3Device complexity
If no foam management system is implemented, then the device complexity is reduced, but the harmful factors generated by foam deteriorate digestion process reliability
Solution Approach 1:
The system implements feedback control by continuously monitoring the pressure differential and automatically triggering foam management actions (anti-foaming agent injection or foam outlet activation) when foam is detected. This feedback mechanism eliminates harmful foam effects while keeping the overall system complexity manageable through automated response
Solution Approach 2:
The digester system provides self-service foam management through automated detection and response. When foam is detected via pressure differential, the system automatically activates foam control mechanisms without external intervention, preventing digestion process disruption while maintaining reasonable device complexity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution effectively detects and manages foam, maintaining optimal digestion conditions by accurately indicating foam presence and preventing its interference with pressure measurements, ensuring reliable operation and efficient digestion.
Implementation Method 1
a first pressure sensor for measuring a first pressure of gas present in said container, said first pressure sensor being in medium through flow connection with a first, upper part of said container, and a second pressure sensor for measuring a second pressure of gas and/or foam present in said container
Implementation Method 2
a tube connecting said second pressure sensor with said second part of the container, said tube having an inlet opening arranged just above said intended level
Implementation Method 3
based on separation biomass and/or sludge and/or a digestate thereof separates under the influence of gravity into stratified layers based on the specific density of the particles and/or substances present in the biomass and/or sludge and/or digestate thereof
Data Source
Figure 1
AI summary
The invention relates to a digester, comprising a container for containing biomass and/or sludge and/or a digestate (3) thereof, preferably up to an intended level (10) of said container, said digester comprising: - a first pressure sensor (8) for measuring a first pressure of gas present in said container, said first pressure sensor being in medium through flow connection with a first, upper part of said container, and - a second pressure sensor (9) for measuring a second pressure of gas or foam present in said container, said second pressure sensor being in medium through flow connection with a second part of said container, preferably just above said intended level. The invention further relates to a method for detecting a presence of foam in a digester according to the invention.