Pot Reactor for Cement Clinker Difficult Fuel Gasification
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Solution Overview
Problem
Existing cement clinker production plants face challenges in efficiently processing difficult fuels with unpredictable ignition behavior, leading to uneven thermal treatment and potential solid deposits in rotary kilns, due to the high mechanical demands and substantial investments required by existing carbonizing furnaces.
Innovation Solution
A combustion device in the form of a pot reactor or gooseneck reactor is positioned between the rotary kiln and calcinator, where difficult fuels are carbonized, pyrolyzed, or combusted, and the resulting exhaust gases are used to supply heat for calcination, ensuring clean combustion and separating the combustion process from the calcinator to prevent interference with raw meal deacidification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a separate shaft gasifier is used to gasify difficult fuels, then the fuels can be thermally treated, but uniform mixing and rearrangement of the fuels does not occur leading to substantial variations in the gasification process
Solution Approach 1:
The patent replaces the static shaft gasifier with a dynamic fluidized bed reactor where fuels are continuously mixed and rearranged by fluidization. This dynamic environment ensures uniform thermal treatment and stable gasification process by preventing fuel stacking and promoting homogeneous combustion conditions.
Solution Approach 2:
The patent replaces the mechanical charging system of the shaft gasifier with a fluidization-based system. Instead of mechanically stacking fuels from above, the fluidized bed uses gas flow to suspend and continuously mix the fuels, achieving uniform mixing without mechanical rearrangement mechanisms.
2Productivity
If difficult fuels are carbonized in a rotary kiln, then the fuels can be thermally treated, but temperature spikes occur resulting in undesired solid baked-on deposits
Solution Approach 1:
The patent creates a controlled thermal environment in the fluidized bed that replicates the desired carbonization conditions without the harmful effects of rotary kiln operation. By controlling residence time and temperature distribution in the fluidized bed, uniform carbonization is achieved without localized overheating and deposit formation.
Solution Approach 2:
The patent changes the thermal treatment parameters by using fluidized bed technology instead of rotary kiln. The fluidized bed provides more uniform heat distribution and controlled temperature profiles, preventing temperature spikes that lead to solid deposits while maintaining effective carbonization of difficult fuels.
3Productivity
If chunky waste materials are combusted in a separate reactor, then the fuels can be processed, but uniform combustion conditions and uniform raw meal pre-calcination cannot be achieved
Solution Approach 1:
The patent merges the fuel combustion process with the raw meal pre-calcination process in a single fluidized bed reactor. The uniform mixing of fuels and raw meal in the fluidized bed ensures that combustion heat is distributed evenly, providing uniform thermal treatment and pre-calcination conditions for the raw meal.
Solution Approach 2:
The fluidized bed acts as an intermediary that facilitates uniform heat transfer between the combusting fuels and the raw meal. The intense mixing and contact in the fluidized bed environment ensures even distribution of thermal energy, achieving uniform pre-calcination without the need for separate combustion and calcination zones.
4Device complexity
If a carbonizing furnace is arranged above the rotary kiln, then the plant layout is optimized, but high mechanical demands and substantial plant investments are required
Solution Approach 1:
The patent replaces the expensive, mechanically complex carbonizing furnace with a simpler, more economical fluidized bed reactor. The fluidized bed technology requires fewer mechanical components and structural supports, reducing both initial investment costs and ongoing maintenance requirements while achieving the same thermal processing function.
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 configuration allows for controlled and efficient combustion of difficult fuels, preventing temperature spikes and solid deposits, reducing mechanical stress and investment costs by utilizing combustible exhaust gases for calcination, ensuring uniform raw meal pre-calcination and reducing the burden on the calcinator.
Implementation Method 1
a combustion device for difficult fuels, which have unpredictable ignition behavior, generally ignite poorly, or require an ignition aid in the form of strong heating and also initial pyrolysis, carbonizes, pyrolyzes, and/or combusts the difficult fuels
Implementation Method 2
a combustion device for difficult fuels, which have unpredictable ignition behavior, generally ignite poorly, or require an ignition aid in the form of strong heating and also initial pyrolysis, carbonizes, pyrolyzes, and/or combusts the difficult fuels
Implementation Method 3
at least one heat exchanger for preheating raw meal
Implementation Method 4
at least one downstream calcinator for calcining the raw meal
Implementation Method 5
The deacidification and also the sintering of raw meal are endothermic processes, which require thermal energy for the reaction thereof
Implementation Method 6
at least one rotary kiln for sintering the calcinated raw meal
Implementation Method 7
In a further step, the raw meal, which is deacidified by the freeing from CO2, and which consists of the deacidified calciferous rock and of the siliceous rock, which is not yet changed here, is sintered in heat to form various calcium silicate phases
Implementation Method 8
at least one clinker cooler for cooling the sintered cement clinker
Implementation Method 9
The heat energy required for producing cement clinker is supplied to the process by combusting various fuels
Data Source
AI summary
A plant for producing cement clinker, comprising as viewed in the direction of materials flow, a heat exchanger to preheat raw meal, a downstream calciner to calcine the raw meal, a rotary kiln to sinter the calcined raw meal, and a clinker cooler to cool the sintered cement clinker. A combustion device which carbonizes, pyrolysis or burns difficult fuels, is embodied as a pot reactor or gooseneck reactor in an inverted U-shape, and is positioned upstream of the calciner on the flow path of the exhaust gases from the rotary kiln to the calciner, and has a gas outlet that opens out above a tertiary-air line of the clinker cooler into the calciner. As a result, it becomes possible to burn fuel which is lumpy and/or has poor ignitability, and the gases from incomplete combustion in the reactor are available in the calciner in gaseous form for further combustion.