CO2 Exhaust Gas Reprocessing via Pyrolysis
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Solution Overview
Problem
Current methods for reducing CO2 emissions in calcination processes, such as those in the cement industry, are energy-intensive and result in significant CO2 emissions due to the high thermal energy required for calcining furnaces, which also produce CO2 as a by-product, leading to high CO2 loads in flue gases.
Innovation Solution
A method involving the conversion of CO2-containing exhaust gases into pyrolysis gases using pyrolyzable organic mass in a multi-stage reduction process, where the CO2 is converted into pyrolysis gases through a countercurrent process with thermally decomposable organic material, allowing for autothermal operation and significant fossil fuel savings, with the pyrolysis gases being reused as fuel or starting material for chemical processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If calcination processes use fossil fuels to generate high temperatures, then the required thermal energy is provided, but CO2 emissions increase significantly
Solution Approach 1:
The invention changes the chemical composition parameters of the gasifying agent from air (containing oxygen that produces CO2) to pure CO2. This parameter change transforms the harmful CO2 emission into a useful reactant that participates in the gasification process, converting carbonate materials into synthetic fuels while consuming CO2 instead of producing it.
Solution Approach 2:
The invention converts the harmful CO2 emissions from calcination processes into a beneficial gasifying agent. By feeding CO2 into the calcination system, it becomes a reactant that drives the gasification of carbonate materials, transforming a waste product into a valuable resource for producing synthetic fuels and chemicals.
2Quantity of substance
If CO2 is removed from exhaust gases using scrubber systems, then CO2 separation is achieved, but energy consumption increases
Solution Approach 1:
The invention makes the CO2 separation process self-service by using the CO2 itself as the driving force for the gasification reactions. The CO2 that would normally be a waste product is instead utilized to drive the decomposition of carbonate materials, eliminating the need for external energy input required by conventional scrubber systems.
Solution Approach 2:
The invention merges the CO2 separation function with the gasification process. Instead of separating CO2 as a standalone step requiring additional energy, the CO2 is directly fed into the gasification reactor where it serves dual purposes: as a reactant for converting carbonate materials and as the separated product that can be further processed or utilized.
3Use of energy by stationary object
If fossil fuels are used for heating in calcination processes, then thermal energy requirements are met, but fossil fuel consumption increases
Solution Approach 1:
The invention recovers and utilizes CO2 that would otherwise be discarded as a waste product. By feeding this recovered CO2 back into the gasification process, it serves as a reactant that replaces fossil fuels for providing the necessary thermal energy, thereby reducing fossil fuel consumption while meeting thermal energy requirements.
Solution Approach 2:
The invention gives CO2 multiple functions: it serves as the gasifying agent for converting carbonate materials, provides thermal energy through the exothermic gasification reactions, and produces valuable synthetic fuels and chemicals. This multi-functionality eliminates the need for separate fossil fuel combustion for heating purposes.
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 significantly reduces fossil fuel consumption and CO2 emissions by utilizing pyrolysis gases produced from the reprocessing of CO2-containing exhaust gases, enabling efficient energy use and minimizing environmental impact.
Implementation Method 1
the CO2-containing exhaust gas is fed in countercurrent to thermally decomposable organic mass and thereby converted into pyrolysis gases
Implementation Method 2
thermally decomposable organic mass
Data Source
Figure 1
AI summary
The invention relates to a method for reprocessing CO2-containing exhaust gases in a multistage reduction process. The CO2-containing exhaust gas is conducted in the counter stream to a solid mass stream of inert bulk material and organic material that can be thermally decomposed through a plurality of zones (4, 3, 2, 1) into a pressure equalization region and is thereby converted into pyrolysis gases. In the flow direction of the solid mass stream in a fuel gas production stage (1) at 250 - 700°C, the organic matter is thermally decomposed under reducing conditions into short-chained hydrocarbons, hydrogen and carbon monoxide to produce coke and residue. In an intermediate stage (2) with increasing temperature, oxidation of the pyrolysis coke is carried out, wherein the developing carbon monoxide is suctioned off counter to the solid mass stream in the direction of the fuel gas production stage (1). In a carbon monoxide production stage (3) at 800 - 1,600°C, the remaining coke residue is converted with carbon dioxide into carbon monoxide by setting the pressure and temperature according to the Boudouard equilibrium. In a cooling stage (4), the developing solid residual material and the bulk material are cooled in the CO2 counter stream to below 100°C and are separated, wherein the bulk material is returned to the cycle.