Reactor for Carbonaceous Material Conversion
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Solution Overview
Problem
Cement production is inefficient in utilizing alternative fuels due to incomplete combustion and fluidization issues with Geldart C materials, leading to thermal energy limitations and operational challenges such as hot or cold spots, sedimentation, and buildup formation in calciners.
Innovation Solution
A method involving a reactor that contacts carbonaceous materials with a powder material at elevated temperatures in a reducing atmosphere, creating dual flow regimes to enhance mixing and separation of volatiles, which are then separated by gravity, reducing the risk of sedimentation and buildup, and utilizing a reactor design with counter-flow and fluidizing means to improve contact time and heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If alternative fuels are injected directly into a calciner, then thermal energy can be provided to cement manufacturing, but incomplete combustion occurs due to insufficient residence time and limited particle residence time
Solution Approach 1:
The invention divides the fuel conversion process into two separate stages: (1) pyrolysis in a dedicated reactor where carbonaceous material is converted to volatiles and char, and (2) combustion of the resulting char in the calciner. This segmentation allows each process to occur under optimized conditions, ensuring complete combustion while efficiently utilizing thermal energy.
Solution Approach 2:
The invention performs preliminary pyrolysis of the carbonaceous material in a dedicated reactor before introducing it to the calciner. This preliminary action converts the fuel into a more reactive form (char and volatiles) that combusts more completely and efficiently in the calciner, resolving the contradiction between thermal energy utilization and combustion completeness.
2Use of energy by moving object
If cement raw meal is fluidized to enhance mixing, then heat transfer improves, but cracks and channeling occur due to cohesive interparticle forces in Geldart C materials
Solution Approach 1:
The invention extracts the carbonaceous material from the cement raw meal stream and processes it separately in a dedicated reactor. This separation removes the problematic Geldart C material that causes fluidization instability, allowing the remaining cement raw meal to be fluidized effectively for efficient heat transfer without cracks or channeling.
Solution Approach 2:
The invention introduces an intermediary processing step (pyrolysis reactor) between fuel introduction and calciner processing. This intermediary unit converts the carbonaceous material into char and volatiles, which then interact with the cement raw meal in a controlled manner, preventing fluidization issues while maintaining effective heat and mass transfer.
3Use of energy by moving object
If coarse alternative fuel particles are added to cement meal, then thermal energy contribution increases, but sedimentation and buildup formation occur due to density differences
Solution Approach 1:
The invention utilizes phase transition during pyrolysis, where coarse carbonaceous material is heated to convert it into volatiles (gas phase) and char (fine solid particles). This phase transition transforms the coarse fuel particles into a form that can be uniformly distributed in the cement meal without sedimentation, while maintaining high thermal energy contribution.
Solution Approach 2:
The invention changes the physical parameters of the alternative fuel through pyrolysis processing. The coarse fuel particles are converted into fine char particles with different density characteristics, and the process parameters (temperature, residence time) are optimized to ensure the converted material maintains suspension in the cement meal stream, preventing buildup while maximizing energy utilization.
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 efficiently converts carbonaceous materials into volatiles and a stable converted material, reducing the risk of hot or cold spots, improving thermal energy utilization, and maintaining process stability by controlling temperature and fluidization, thereby enhancing the use of alternative fuels in cement production.
Implementation Method 1
Solid material such as carbonaceous material and/or a powder material is added to the reactor. The carbonaceous material has a conversion temperature and the powder material has a temperature higher than the conversion temperature of the carbonaceous material.
Implementation Method 2
The carbonaceous material and the powder material is contacted in an atmosphere configured to no more than partially oxidize carbon to CO2, to obtain at least a partial conversion of the carbonaceous material into a converted material and a volatile product.
Implementation Method 3
separating by specific gravity by directing a gas flow comprising the volatile product in a substantially upwards direction to provide a first fraction substantially comprising the volatile product and a second fraction substantially comprising additional components
Implementation Method 4
gas pulses fluidize the particles to facilitate movement of the solids through the reactor
Data Source
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AI summary
A method for the conversion of a carbonaceous material. The method comprising the steps of providing a carbonaceous material, providing a hot powder material and contacting the carbonaceous material and the powder material in an atmosphere configured to no more than partially oxidize carbon to CO2. The carbonaceous material is at least a partial converted into volatiles. The volatiles are separated from the additional components by specific gravity.