Dynamic Injector-Mixer for Sludge Thermal Hydrolysis
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Solution Overview
Problem
Existing methods of continuous thermal hydrolysis of sludge with high dry content face challenges in efficient steam injection and mixing, leading to suboptimal performance and increased energy consumption, particularly when sludge dry content exceeds 20%, resulting in reduced anaerobic digestion efficiency and mechanical constraints.
Innovation Solution
The method involves simultaneous primary and secondary dynamic mixing of recovered and fresh steam with sludge upstream to the thermal hydrolysis reactor, ensuring a homogeneous mixture is achieved before entering the reactor, allowing for efficient steam condensation and reduced energy consumption, enabling treatment of sludge with higher dry content without performance loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If steam is injected directly into high dry content sludge (>20%) in conventional continuous thermal hydrolysis, then the sludge can be heated, but the steam injection and mixing becomes inefficient leading to suboptimal thermal hydrolysis performance and increased energy consumption
Solution Approach 1:
The patent applies preliminary action by pre-mixing steam with water to generate a steam-water mixture before introducing it to the sludge. This preliminary preparation ensures optimal mixing conditions are established beforehand, allowing efficient heat transfer to high dry content sludge without the energy losses associated with direct steam injection into viscous material.
Solution Approach 2:
The patent changes the physical parameters of the heating medium by using a steam-water mixture instead of pure steam. This parameter change (composition ratio of steam to water) optimizes the mixing characteristics and heat transfer efficiency, enabling effective thermal hydrolysis of sludge with high dry content while reducing energy consumption.
2Productivity
If conventional thermal hydrolysis methods are used for sludge with dry content exceeding 20%, then treatment can proceed, but mechanical constraints increase and anaerobic digestion efficiency decreases
Solution Approach 1:
The patent applies preliminary action by performing steam-water mixing before sludge treatment. This pre-preparation creates optimal conditions for subsequent anaerobic digestion by ensuring uniform heat distribution and appropriate moisture content, thereby improving digestion efficiency while avoiding mechanical complications that would arise from treating high dry content sludge directly.
Solution Approach 2:
The patent changes the moisture content parameter of the heating medium by using a steam-water mixture. This parameter adjustment ensures that the sludge receives appropriate moisture during thermal hydrolysis, preventing excessive dryness that would otherwise create mechanical handling constraints and reduce anaerobic digestion efficiency.
3Loss of energy
If recovered steam is not recirculated in the thermal hydrolysis process, then the process is simpler to operate, but energy consumption increases
Solution Approach 1:
The patent applies the recovering principle by capturing recovered steam from the thermal hydrolysis process and recirculating it back to the steam-water mixing stage. This recovery system prevents energy loss by reusing the thermal energy contained in the recovered steam, thereby reducing overall energy consumption while maintaining operational simplicity through an integrated recirculation loop.
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 approach enhances thermal hydrolysis efficiency, reduces energy consumption, and allows for smaller reactor volumes, effectively treating sludge with high dry content while optimizing steam condensation and reducing mechanical constraints, thereby improving overall process performance and energy utilization.
Implementation Method 1
simultaneously carrying out the injection of recovered steam into said sludge and mixing said sludge with said recovered steam by means of a primary dynamic injector-mixer
Implementation Method 2
mixing said sludge with said recovered steam... so as to obtain a primary uniform mixture of pre-heated sludge
Implementation Method 3
mixing said primary uniform mixture with said fresh steam by means of a secondary dynamic injector-mixer
Implementation Method 4
so as to obtain a uniform secondary mixture of sludge heated to the desired temperature of thermal hydrolysis
Implementation Method 5
prompting an essentially plug type flow of this secondary uniform mixture into said reactor for a residence time that is sufficient and at a temperature that is sufficient to enable the thermal hydrolysis of the organic matter
Implementation Method 6
at a temperature that is sufficient to enable the thermal hydrolysis
Implementation Method 7
cooling said secondary uniform mixture when it exits from said means for producing recovered steam to a temperature enabling the subsequent digestion of the hydrolyzed organic matter
Implementation Method 8
a step for conveying water to another inlet of said heat exchanger; said secondary uniform mixture transferring at least a part of its heat to said water to indirectly produce said recovered steam
Data Source
AI summary
The invention pertains to a method for the continuous thermal hydrolysis of sludge to be treated, containing organic matter, said method comprising the steps of simultaneously carrying out the injection of recovered steam into said sludge and mixing said sludge with said recovered steam by means of a primary dynamic injector-mixer so as to obtain a primary uniform mixture; simultaneously carrying out the injection of fresh steam into said primary uniform mixture and mixing said primary uniform mixture with said fresh steam by means of a secondary dynamic injector-mixer so as to obtain a secondary uniform mixture of sludge; conveying said secondary uniform mixture towards a tube reactor under pressure and prompting an essentially plug-type flow of this secondary uniform mixture into said reactor for a residence time that is sufficient and at a temperature that is sufficient to enable the thermal hydrolysis of the organic matter present in this secondary uniform mixture; producing said recovery steam within means for the production of recovered steam from said secondary uniform mixture obtained at exit from said tubular reactor; cooling said secondary uniform mixture when it exits said means for producing recovery steam to a temperature enabling the subsequent digestion of the hydrolyzed organic matter that it contains.