Heating Filter Press Drying Sludge via Hydrothermal Carbonization
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Solution Overview
Problem
Existing drying methods for dehydrated products, such as sludge from wastewater treatment, fail to achieve optimal dryness levels for thermal recovery, leading to inefficient energy consumption and lengthy drying times, especially when using heating filter presses.
Innovation Solution
A method involving hydrothermal carbonization, mechanical compression, and heat transfer using a heat exchanger and heating filter press, which recovers energy and optimizes energy consumption by reusing discharged heat, allowing for drying to a dryness value of 50-95%.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a heating filter press is used to dry sludge to high dryness levels (90%), then thermal recovery efficiency is improved, but energy consumption increases and drying time becomes excessively long
Solution Approach 1:
The invention applies preliminary mechanical compression to the sludge before thermal drying to remove a significant portion of water in advance. This pre-treatment reduces the water content from initial levels (around 80-90% moisture) to intermediate levels (50-65% moisture), thereby reducing the energy required for subsequent thermal drying and shortening the drying time while still achieving the target 90% dryness for optimal thermal recovery
Solution Approach 2:
The invention implements continuous mechanical compression followed by continuous thermal drying in an integrated system. The mechanical compression continuously removes water under pressure while the thermal drying continuously evaporates remaining moisture, maintaining continuous useful action throughout the drying process rather than using intermittent or batch operations, thereby optimizing energy efficiency and reducing total drying time
2Productivity
If mechanical compression is applied to sludge for dehydration, then water removal efficiency is improved, but the structural complexity of the drying system increases
Solution Approach 1:
The invention merges the mechanical compression system and thermal drying system into a single integrated drying apparatus. The mechanical compression unit with pressurization capability is combined with the thermal drying chamber in one system, allowing water removal through both mechanical squeezing and thermal evaporation in sequence without requiring separate standalone equipment, thereby improving water removal efficiency while controlling overall system 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 method significantly reduces energy consumption and shortens drying times by recycling heat energy, making it suitable for carbonized products and optimizing the dimensions and functionality of the drying installation.
Implementation Method 1
a step of transfer of heat, during which, by means of the heat exchanger, transfer takes place to a heat transfer fluid, for example water, of at least part of the heat contained in the product to be dehydrated
Implementation Method 2
during the heating step, the heat transfer fluid which has been subjected to the step of transfer of heat is circulated in channels formed in at least one of said plates
Implementation Method 3
the product to be dehydrated contained in the mechanical compression system is compressed by application of a dehydration pressure P1, preferably of more than 0.5 MPa
Data Source
AI summary
The present invention relates to the field of heat treatment of a product to be dehydrated, such as sludge from a waste water treatment process. The present invention relates more particularly to a method and to a facility for drying such a product, making it possible to implement a hydrothermal carbonization operation on reactor 1 followed by a filtering and drying operation, preferably on a heating filter press 6. In order to dry said product in the heating filter press 6, a heat-transfer fluid from a heat exchanger 2 is made to flow in said heating filter press. The heat exchanger 2 is arranged so as to transfer, to the heat-transfer fluid, at least some of the heat contained in the product to be dehydrated that is output from the reactor 1.