Rotating Torrefaction Reactor Cooling Tubes Prevent Tar
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Solution Overview
Problem
During the low-temperature torrefaction of biomass, the formation of sticky tar on reactor surfaces interferes with the torrefied product, as the pyrolytic gas cools and adheres to the inner surfaces, requiring effective control of reaction velocity and surface temperature to prevent this issue.
Innovation Solution
The apparatus employs a rotating reactor with regularly spaced cooling tubes that are heated internally to maintain a temperature above the liquefying point of pyrolytic gas, ensuring the tar does not form and adheres to the surfaces, by using a counter-current flow cooling method where the cooling fluid is introduced at the bottom and released at the top, preventing tar formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the reactor jacket is cooled to control reaction velocity, then the exothermic torrefaction reaction is controlled, but sticky tar forms on the inner surfaces of the reactor
Solution Approach 1:
The patent applies local quality by differentiating the thermal treatment of different regions: the reactor jacket is cooled to control the exothermic reaction, while the inner surface temperature is maintained above the tar liquefaction point to prevent tar adhesion. This is achieved through internal heating elements that locally heat the reaction zone without affecting the overall cooling strategy.
Solution Approach 2:
The patent implements preliminary anti-action by pre-heating the inner surface of the reactor before tar formation can occur. The heating elements are activated to maintain the surface temperature above the liquefaction point of pyrolytic gas, preventing tar from adhering to the surface in the first place rather than addressing tar formation after it occurs.
2Object-generated harmful factors
If the inner surface temperature is maintained above tar liquefaction point, then sticky tar formation is prevented, but additional heating equipment is required
Solution Approach 1:
The patent applies multi-functionality by designing the internal heating elements to serve dual purposes: they heat the biomass material during torrefaction and simultaneously maintain the inner surface temperature to prevent tar formation. This eliminates the need for separate heating and cooling systems, reducing overall device complexity.
Solution Approach 2:
The heating elements are positioned to utilize the exothermic heat from the torrefaction reaction itself to maintain inner surface temperature, reducing or eliminating the need for external heating energy input. The system serves itself by using the reaction's own heat to prevent tar adhesion.
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 effectively prevents the formation of sticky tar on reactor surfaces, ensuring the torrefied product is not contaminated and can be efficiently collected, maintaining the product's hydrophobic and high carbon content characteristics.
Implementation Method 1
cooling tubes (15) which are adapted be cooled by suitable cooling fluid
Implementation Method 2
The heater 4 is connected at its outlet end 5 to an inlet end 11 of at least one torrefaction reactor 10... The internal jacket 14 of the reactor 10 is adapted to be heated by a suitable heating fluid
Implementation Method 3
a pyrolytic gas is formed. This pyrolytic gas when cooled forms a sticky tar
Implementation Method 4
the cooling fluid is introduced at the bottom and released at the top, preventing tar formation
Data Source
Figure 1
Figure 2~3
AI summary
The invention relates to method for torrefaction of biomass material at low temperature comprising the steps of: - providing a finely divided biomass material, - feeding said finely divided biomass material to at least one heater (4) for drying and heating said biomass material, - feeding said dried biomass material to at least one rotating torrefaction reactor (10), said reactor being provided with a heated jacket (14) and in the circumferential direction regularly spaced internal cooling tubes (15), whereby said cooling tubes (15) are so arranged that at least some of them, during rotation of said at least one reactor, will be in contact with and cool the biomass material being torrefied. The invention relates also to an apparatus for carrying out the method.