Anaerobic Process Water Cleaning With Inorganic Solids Control
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Solution Overview
Problem
The challenge in paper manufacturing from waste paper is the high content of inorganic solids, particularly chalk, in process water, which interferes with the operation of anaerobic reactors by altering the specific weight of microorganism pellets, leading to malfunction and reduced efficiency.
Innovation Solution
A method for continuous cleaning of process water using an anaerobic reactor with gas separators, where the inorganic solids content is monitored and excess solids are removed to a solid-liquid separator for separation into depleted and enriched fractions, ensuring the solids content remains below a set limit, thereby preventing reactor malfunction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If process water is continuously circulated in the anaerobic reactor for cleaning, then organic impurities are effectively broken down, but inorganic solids accumulate and alter the specific weight of microorganism pellets, causing reactor malfunction
Solution Approach 1:
The patent extracts inorganic solids from the process water circulation system by implementing a solid-liquid separation unit that continuously removes suspended inorganic particles before the water re-enters the anaerobic reactor. This prevents accumulation of inorganic solids that would otherwise alter microorganism pellet specific weight and cause reactor malfunction, while maintaining the beneficial continuous circulation for organic impurity breakdown.
Solution Approach 2:
The patent implements a feedback control mechanism where the solid-liquid separation unit continuously monitors and adjusts the removal of inorganic solids based on their accumulation in the process water. This feedback loop maintains the inorganic solids content within acceptable limits, preventing the specific weight alteration that would lead to reactor malfunction while preserving continuous operation for organic degradation.
2Reliability
If manual maintenance is performed to remove accumulated inorganic solids, then reactor performance is restored, but continuous operation is interrupted and productivity decreases
Solution Approach 1:
The patent implements continuous solid-liquid separation that operates throughout the entire process water circulation cycle, eliminating the need for periodic manual maintenance interruptions. The separation unit continuously removes inorganic solids as they accumulate, maintaining reactor performance without stopping the anaerobic cleaning process, thereby preserving continuous productivity.
Solution Approach 2:
The system performs self-maintenance through the automated solid-liquid separation unit that continuously monitors and removes inorganic solids without requiring external manual intervention. The reactor effectively cleans itself by integrating the separation function into the circulation loop, preventing performance degradation before it occurs and eliminating productivity losses from manual maintenance.
3Quantity of substance
If the specific weight of microorganism pellets is altered by inorganic solids deposition, then pellets sink to the reactor base, but this prevents gas separation and reduces cleaning efficiency
Solution Approach 1:
The patent extracts inorganic solids from the process water before they can deposit on microorganism pellets by implementing continuous solid-liquid separation. This prevents the alteration of pellet specific weight that would cause sinking to the reactor base and subsequent failure of gas separation function, maintaining reliable anaerobic cleaning operation.
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 method ensures efficient and reliable anaerobic cleaning by maintaining optimal reactor operation without manual maintenance, allowing for continuous and high-efficiency process water cleaning.
Implementation Method 1
the process water is contacted, in the anaerobic reactor, with anaerobic microorganisms in order to break down impurities contained in the process water
Implementation Method 2
process water comprising solids dissolved and dispersed therein being continuously supplied, from the anaerobic reactor, to a solid-liquid separator for separation into a fraction depleted of inorganic solids and a fraction enriched with inorganic solids
Data Source
AI summary
The present invention relates to a method and to a device for continuous cleaning of process water circulating in a device for treating waste paper. The process water is supplied, from a unit of the device, to an anaerobic reactor comprising a gas separator, and the cleaned process water is returned back to a unit of the device, wherein this unit is selected from: a pulper; screening device; dewatering unit; oxidation/reduction unit; centrifugal screening device; fine screening device; paper-machine mould section; paper-machine press section; reject treatment unit; fibre recovery unit; and drying section; wherein the content of inorganic solids in the reactor is measured and, if this content exceeds a pre-set limit value, process water from the reactor is continuously fed to a solid-liquid separator for separation into a fraction that is depleted of inorganic solids and a fraction that is enriched with inorganic solids, wherein the fraction that is depleted of inorganic solids is returned to the anaerobic reactor and the fraction that is enriched with inorganic solids is conveyed away out of the device, until the content of inorganic solids in the process water is less than the limit value.