Calciner Injector Rapid Transit for CaO Regeneration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Commercial hydrogen generation via steam reforming of natural gas faces challenges due to large unit sizes and methane slip, with rotary kiln calciners being limited by high operating temperatures and residence times, leading to particle sintering and NOx pollutant production.
Innovation Solution
A calciner injector system that rapidly directs hot vitiated air to calcium carbonate particles to regenerate calcium oxide, reducing residence time and NOx production, while maintaining efficient calcination and hydrogen yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rotary kiln calcination units are used to regenerate CaO, then CaO regeneration is achieved, but particle sintering occurs due to high residence time and high operating temperature
Solution Approach 1:
The patent applies the 'Skipping (Rushing through)' principle by rapidly moving calcium carbonate particles through the calciner zone. The particles are injected at the inlet and quickly transported through the high-temperature zone, minimizing residence time to less than 1 second. This rapid transit prevents sintering while still achieving complete calcination to regenerate CaO for continuous reuse in the hydrogen generation process.
2Productivity
If rotary kiln calcination units operate at high temperatures above 1523°C, then CaO regeneration is efficient, but NOx pollutant production increases
Solution Approach 1:
The patent resolves the NOx production issue by rapidly skipping through the high-temperature zone. The calcium carbonate particles are quickly transported from injection to calcination completion in less than 1 second, preventing the prolonged exposure needed for NOx formation. This rapid transit maintains high calcination efficiency while suppressing NOx generation to negligible levels.
Solution Approach 2:
The patent extracts and removes the harmful thermal field exposure time from the process. By separating the high-temperature calcination function from prolonged residence time, the system achieves efficient CaO regeneration without the harmful side effect of NOx production. The particles are taken through the hot zone just long enough for calcination, then quickly removed to prevent pollutant formation.
3Productivity
If commercial hydrogen generation units are made larger, then hydrogen production capacity increases, but methane slip increases
Solution Approach 1:
The patent changes the operational parameters of the calcination process by using rapid injection and short residence time (less than 1 second) at controlled high temperature. This parameter change allows smaller reformer units to achieve high hydrogen production capacity while maintaining complete methane conversion, eliminating methane slip without requiring excessive unit size.
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
The system achieves efficient regeneration of calcium oxide with reduced NOx emissions and particle sintering, allowing for smaller, more efficient hydrogen generation units with improved methane conversion and lower pollutant levels.
Implementation Method 1
At least one flow nozzle is adaptable to receive the heated air volume and discharge the heated air volume at the discharge end. The at least one flow nozzle is angularly oriented to directly impinge the plurality of calcium carbonate particles discharged from the at least one transfer tube with the heated air volume.
Implementation Method 2
The calcium oxide reacts with the CO2 in a separation reaction, producing a solid calcium carbonate (CaCO3) and absorbing the CO2.
Implementation Method 3
To regenerate a solid form of calcium oxide (CaO) for continued reaction with the CO2, the solid CaCO3 particles can then be placed in a calciner wherein they are heated according to the following reaction: CaCO3+heat→CaO(s)+CO2 (g).
Data Source
AI summary
An injection device transfers calcium carbonate particles for regeneration into calcium oxide. The device includes an injector body having an inlet end which receives a heated air volume, and a discharge end. At least one transfer tube disposed through a portion of the injector body discharges the calcium carbonate particles at the discharge end. At least one flow nozzle receives the heated air volume and discharges the heated air volume at the discharge end. Each flow nozzle is angularly oriented to directly impinge the plurality of calcium carbonate particles discharged from the transfer tube with the heated air volume. A flow splitter can also be connected to the device to split the calcium carbonate particles into multiple flow streams.