Sub-molten Salt Ash Removal for Solid Carbonaceous Material
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Solution Overview
Problem
Current methods for removing ash from solid carbonaceous materials, such as coal, are inefficient and require high temperatures, pressures, and large amounts of alkali and water, making them costly and difficult to operate.
Innovation Solution
A method involving a sub-molten salt medium of alkali with a mass fraction of 50% or more is mixed with the solid carbonaceous material, heated, and then subjected to acid washing treatment to efficiently remove ash, reducing the need for alkali and water and lowering recovery costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional acid-alkali method is used for ash removal, then ash removal efficiency is improved, but reaction conditions become rigorous (high temperature 150-250°C, high pressure) and operating costs increase
Solution Approach 1:
The invention changes the concentration parameter of the alkali medium from conventional dilute solutions to sub-molten salt medium with alkali mass fraction of 30-80%. This parameter change enables the reaction to proceed at lower temperatures (80-200°C) and atmospheric pressure, resolving the contradiction between ash removal efficiency and ease of operation by achieving both high efficiency and mild conditions
Solution Approach 2:
The invention uses a composite alkali system comprising sub-molten salt medium combined with specific additives (CaO, MgO, SiO2, Al2O3, Fe2O3, TiO2, ZnO, MnO, PbO, Bi2O3, or their mixtures). This composite material approach enhances the ash removal efficiency while maintaining mild reaction conditions, addressing both aspects of the contradiction
2Manufacturing precision
If conventional acid-alkali method is used for ash removal, then ash content is reduced, but water consumption and alkali usage increase significantly
Solution Approach 1:
By changing the concentration parameter to sub-molten salt medium (30-80% alkali mass fraction), the invention reduces the total quantity of alkali and water needed. The high concentration medium provides sufficient reactive components while minimizing the volume of liquid required, thus reducing both water and alkali consumption while achieving low ash content
Solution Approach 2:
The sub-molten salt medium serves multiple functions simultaneously: it acts as the reaction medium, provides the alkali for ash removal, and facilitates product separation. This self-service capability reduces the need for additional water and alkali that would be required in conventional methods for washing and separation processes
3Manufacturing precision
If conventional acid-alkali method is used for ash removal, then ash is removed effectively, but handling capacity of solid carbonaceous materials decreases
Solution Approach 1:
The invention changes the physical state and concentration parameters of the alkali medium to sub-molten salt form. This parameter change improves the medium's penetrating ability and reactivity, enabling effective ash removal at lower temperatures and shorter reaction times, thereby increasing the handling capacity of solid carbonaceous materials while maintaining removal effectiveness
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 allows for ash removal under milder conditions, increasing handling capacity and reducing costs, while achieving a yield of ultra-pure coal with ash content below 1%.
Implementation Method 1
heating the mixture to react the alkali with the ash in the solid carbonaceous material to be treated in the sub-molten salt medium of the alkali
Implementation Method 2
subjecting the first solid product to an acid washing treatment with an acid liquor and performing solid-liquid separation once more to obtain a second solid product and a pickling solution
Data Source
AI summary
A method for removing ash from a solid carbon material: Reaction conditions are mild, and ash may be removed more effectively. The ash removing method comprises: S1) mixing an alkaline sub-molten salt medium and a solid carbonaceous material to be treated, heating so that alkali and ash in the solid carbonaceous material to be treated react in the alkaline sub-molten salt medium, and performing solid-liquid separation on a mixed slurry resulting from the reaction to obtain a first solid product and an alkali treatment solution, wherein in the alkaline sub-molten salt medium, the mass fraction of the alkali is greater than or equal to 50%; S2) using an acid solution to perform acid cleaning treatment on the first solid product, and performing solid-liquid separation again to obtain a second solid product and an acid cleaning solution.