Combustion Process Using Mobile Solid Transfer Medium
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Solution Overview
Problem
Current organic matter combustion processes for heat and/or electricity production face challenges in controlling temperature and chemical composition, leading to the production of harmful pollutants like nitrogen oxides, dioxins, and furans, and suffer from inefficiencies and equipment corrosion due to the complexity and energy intensity of traditional solutions.
Innovation Solution
A combustion process using a mobile transfer medium of independent solid particles that fills the entire horizontal section of the enclosure, circulating vertically under gravity, allowing for controlled combustion stages and reinjection of fumes, with a device comprising oxidant inlets, heat exchangers, and a system for separating and reusing the transfer medium to enhance energy recovery and reduce pollutant production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional combustion processes (grate boiler, fluidized bed, spray furnace) are used for heat and/or electricity production, then energy recovery from organic matter is achieved, but temperature and chemical composition cannot be precisely controlled, leading to production of harmful pollutants (NOx, dioxins, furans) and equipment corrosion
Solution Approach 1:
The combustion process is divided into multiple sequential zones within a single reactor: a first combustion zone for initial oxidation, a second combustion zone for complete combustion at controlled temperatures, and a third combustion zone for post-combustion and pollutant destruction. This segmentation allows precise control of temperature and chemical composition in each zone, reducing harmful emissions without requiring multiple separate reactors or complex external treatment systems.
Solution Approach 2:
A bed material (such as sand, olivine, or dolomite) is introduced as an intermediary substance that facilitates heat transfer and temperature control within the combustion zones. The bed material absorbs and distributes thermal energy, preventing localized hot spots that would generate NOx and dioxins, while maintaining stable combustion conditions throughout the reactor.
2Object-affected harmful factors
If circulating fluidized bed combustion is used to improve fume quality, then pollutant production is reduced, but the installation becomes complex and energy-intensive due to the need for fluidizing heavy sandy particles
Solution Approach 1:
The system transitions from a static fixed-bed combustion system to a dynamic fluidized-bed system where the bed material is continuously circulated between the combustion zones and a heat exchange section. This dynamic circulation allows the same bed material to repeatedly absorb heat and transfer it to the combustion zones, maintaining stable temperatures and reducing pollutants without requiring continuous high energy input for fluidization.
Solution Approach 2:
The bed material serves multiple functions simultaneously: it acts as a heat transfer medium, a temperature control agent, a support for combustion reactions, and a catalyst for pollutant destruction. This multi-functionality eliminates the need for separate systems for each function, reducing overall energy consumption and system complexity.
3Device complexity
If fixed bed combustion is used, then the installation is simple, but temperature control is poor and localized hot spots (>1200°C) cause NOx production and equipment damage
Solution Approach 1:
The bed material acts as an intermediary heat transfer medium that distributes thermal energy uniformly throughout the combustion zones. By introducing this intermediate substance, the system achieves the temperature control and uniformity of a fluidized bed while maintaining the structural simplicity and low complexity of a fixed bed combustion system.
Solution Approach 2:
The reactor is segmented into multiple combustion zones with different temperature profiles and oxygen concentrations. This segmentation allows the system to maintain simple overall structure while achieving precise temperature control in each zone, preventing localized hot spots that would generate NOx and damage equipment.
4Reliability
If high excess air is used to prevent incomplete combustion, then combustion completeness is improved, but temperature control becomes difficult and NOx formation increases
Solution Approach 1:
The combustion process is segmented into zones with progressively increasing oxygen supply. The first combustion zone uses limited air for initial oxidation, the second zone introduces additional air for complete combustion, and the third zone provides post-combustion air. This segmented air supply ensures complete combustion while maintaining precise temperature control in each zone, preventing excessive temperatures that would form NOx.
Solution Approach 2:
The bed material is preheated in a separate heat exchange section before being introduced into the combustion zones. This preliminary heating reduces the amount of excess air needed to achieve complete combustion, as the preheated bed material contributes to the thermal energy required for combustion, thereby improving temperature control and reducing NOx formation.
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 stabilizes temperature gradients, improves energy efficiency, reduces pollutant formation, and extends equipment lifespan by promoting homogeneous heat exchange and minimizing energy consumption, while allowing for the recovery of energy typically lost in downstream processes.
Implementation Method 1
circulating vertically under gravity
Implementation Method 2
The combustion reaction is ensured by highly exothermic oxidation of the material
Implementation Method 3
highly exothermic oxidation of the material
Implementation Method 4
the fumes produced are usually extracted from the upper part, after having passed through a hearth lined with layers of pressurized tubes, called membranes, in which circulate water to be vaporized
Implementation Method 5
particularly suitable for the combined production of heat and electricity, in other words cogeneration, using a cycle of Rankine or equivalent, using in particular a steam turbine and an alternator
Data Source
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AI summary
The present invention relates to a method for the combustion of organic matter (22), characterised in that it comprises a step of mixing a transfer medium (23) made up of independent solid particles, with organic matter (22), and circulating said mixture in an enclosure (10), and in that said mixture undergoes combustion with the aid of a combustion agent introduced into the enclosure (10).