Laminar Stream Reactor for Continuous Hydrochar Production
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Solution Overview
Problem
Current reactors are inadequate for continuous processing of solid-fluid mixtures, particularly biomass, as they often lead to caking and blockages due to unusual reaction times exceeding 20 minutes, lacking suitable designs for such applications.
Innovation Solution
A laminar stream reactor design with specific tube section diameters and orientations, allowing for continuous flow and minimizing turbulence, where the diameter of the lower tube part is smaller than the descending section, and connected units enable prolonged residence times and efficient processing without mechanical agitating devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional reactors are used for continuous processing of solid-fluid mixtures, then processing capability is improved, but caking and blockages occur due to reaction times exceeding 20 minutes
Solution Approach 1:
The reactor is divided into multiple tube sections with different diameters (ascending, holding, descending sections). This segmentation allows different flow regimes in different sections, enabling continuous processing while preventing caking through controlled turbulence in specific zones.
Solution Approach 2:
The reactor design incorporates dynamic flow conditions by varying tube diameters along the flow path. The ascending section creates turbulent flow for mixing, the holding section maintains laminar flow for reaction, and the descending section creates turbulence to prevent settling and caking, enabling reliable continuous operation.
2Stability of the object's composition
If tube diameter is reduced to minimize turbulence, then flow control is improved, but residence time is insufficient for complete reaction
Solution Approach 1:
The reactor extends in the spatial dimension by using multiple tube sections with different diameters arranged in sequence. This allows the system to provide both turbulent flow (in smaller diameter sections) and extended residence time (through the series arrangement of multiple sections) without contradiction.
Solution Approach 2:
Different sections of the reactor have different tube diameters optimized for different functions: ascending section for turbulent mixing, holding section for laminar reaction, and descending section for preventing settling. This local optimization allows simultaneous achievement of flow control and adequate residence time.
3Stability of the object's composition
If mechanical agitating devices are added to prevent caking, then mixing is improved, but device complexity and energy consumption increase
Solution Approach 1:
The reactor replaces mechanical agitating devices with fluid dynamic control achieved through varying tube diameters. The flow regime itself (laminar or turbulent) provides the mixing and anti-caking function, eliminating the need for mechanical components and reducing device complexity and energy consumption.
Solution Approach 2:
The flowing mixture itself performs the mixing and anti-caking function through the controlled flow regimes created by the tube geometry. The system uses its own operational parameters (flow velocity, tube diameter) to achieve mixing without external mechanical intervention.
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
Enables economic and continuous conversion of solid-fluid mixtures, preventing caking and blockages, with increased carbon content and fuel value in hydrochar production, and efficient CO2 capture, while maintaining low energy expenditure and high carbon efficiency.
Implementation Method 1
A laminar stream reactor design with specific tube section diameters and orientations, allowing for continuous flow and minimizing turbulence
Implementation Method 2
at least the descending tube sections are essentially vertical or are at least inclined to the horizontal
Implementation Method 3
Biomass is heated together with water to about 180°C and 15 - 20 bars of pressure
Implementation Method 4
Hydrothermal carbonization (HTC), a chemical method for the simple and highly efficient production of hydrochar
Implementation Method 5
The chemical conversion reaction is exothermic releasing up to 34 percent of the energy contained in the feedstocks
Data Source
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AI summary
A laminar stream reactor for the production of hydrochar of a solid-fluid mixture of water and a carbon-containing component, wherein the solid-fluid mixture is treated at a temperature of 00 - 300ºC and a pressure of 5 - 70 bar, consists of tubular reactor units of largely vertical holding sections (1,3) and direction-changing diverters (2,4).The holding sections are thereby flown through slower by the solid-fluid mixture than the remaining tube distances, as they have larger diameters.