Continuous Desulfurization Using Regenerable Metal Oxide Sorbents
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Solution Overview
Problem
Current desulfurization processes are costly and inefficient for removing hydrogen sulfide, carbonyl sulfide, carbon disulfide, and thiols/disulfides with four or less carbon atoms from gas mixtures, particularly in concentrations between 5 ppmv and 5,000 ppmv, due to high operating costs, complex equipment, and limited sorbent regeneration capabilities.
Innovation Solution
A continuous desulfurization process using regenerable metal oxide-based sorbents in fixed-bed reactors with a cyclic alternating sequence of desulfurization and regeneration operations, optimized with specific operating parameters for efficient sorbent regeneration and low oxygen concentration oxidizing gas mixture production from air, allowing for stable dynamic sulfur capacity over multiple cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional desulfurization processes are used to remove reduced sulfur species from gas mixtures, then sulfur removal is achieved, but operating costs are high and equipment complexity increases
Solution Approach 1:
The continuous desulfurization process is segmented into multiple fixed bed reactors operating in sequence, with each bed undergoing cyclic desulfurization and regeneration phases. This segmentation allows one bed to be regenerated while others are actively desulfurizing, maintaining continuous operation without requiring complex integrated systems.
Solution Approach 2:
The invention recovers and regenerates the sorbent material after sulfur saturation. Instead of discarding spent sorbent, it is regenerated by heating in an oxygen-containing atmosphere to convert metal sulfides back to metal oxides, allowing multiple reuse cycles and reducing equipment and material costs.
2Reliability
If disposable sorbent materials are used for desulfurization, then sulfur removal is achieved, but operating costs increase due to continuous sorbent replacement
Solution Approach 1:
The sorbent material is regenerated in situ by heating the spent sorbent bed in an oxygen-containing atmosphere, converting metal sulfides back to metal oxides. This recovery process eliminates the need for continuous sorbent replacement, reducing operating costs while maintaining removal effectiveness over multiple cycles.
Solution Approach 2:
The sorbent undergoes parameter changes during cyclic operation, transitioning between reduced (metal sulfide) and oxidized (metal oxide) states. These reversible parameter changes enable the sorbent to be regenerated and reused multiple times, converting a consumable material into a regenerable asset.
3Duration of action of stationary object
If high oxygen concentration regeneration gas is used, then sorbent regeneration is achieved, but sorbent deactivation increases and process stability deteriorates
Solution Approach 1:
The oxygen concentration in the regeneration gas is optimized to a specific range (1-15% by volume) rather than using high oxygen concentrations. This parameter optimization enables sufficient sorbent regeneration while preventing excessive temperature rises and sorbent deactivation, maintaining process stability over multiple cycles.
Solution Approach 2:
The regeneration gas is formulated as a composite mixture containing oxygen (1-15% by volume) combined with inert gases or process gases. This composite composition provides the necessary oxygen for regeneration while the inert components buffer the reaction, preventing runaway temperature increases and sorbent degradation.
4Reliability
If multiple sulfur species are removed simultaneously, then comprehensive desulfurization is achieved, but process complexity increases
Solution Approach 1:
The metal oxide-based sorbent is designed with universal functionality to remove multiple reduced sulfur species (H2S, COS, CS2, thiols, disulfides) through a single desulfurization process. The sorbent's metal oxide structure enables simultaneous reaction with various sulfur compounds, eliminating the need for separate treatment steps for each species.
Solution Approach 2:
All reduced sulfur species are converted to metal sulfides during desulfurization, which are then simultaneously regenerated to sulfur dioxide during the oxidation step. This unified recovery approach handles multiple sulfur species through a single regeneration cycle, simplifying the overall process while achieving comprehensive removal.
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 process significantly reduces the overall cost of sulfur removal, achieves effective desulfurization and regeneration for at least 100 cycles, and simplifies the process, enabling efficient removal of H2S, COS, CS2, thiols, and disulfides without hydrolysis, while minimizing sorbent deactivation and equipment complexity.
Implementation Method 1
The metal oxide-based sorbent removes reduced sulfur species from gas mixtures through adsorption and chemical reaction
Implementation Method 2
The metal oxide-based sorbent removes reduced sulfur species from gas mixtures through adsorption and chemical reaction, forming metal sulfides
Implementation Method 3
The sorbent is regenerated by reacting metal sulfides with oxygen to produce sulfur dioxide and restore the metal oxide
Implementation Method 4
The sorbent is regenerated by reacting metal sulfides with oxygen to produce sulfur dioxide and restore the metal oxide
Data Source
AI summary
A continuous desulfurization process and process system are described for removal of reduced sulfur species at gas stream concentrations in a range of from about 5 to about 5000 ppmv, using fixed beds containing regenerable sorbents, and for regeneration of such regenerable sorbents. The desulfurization removes the reduced sulfur species of hydrogen sulfide, carbonyl sulfide, carbon disulfide, and/or thiols and disulfides with four or less carbon atoms, to ppbv concentrations. In specific disclosed implementations, regenerable metal oxide-based sorbents are integrated along with a functional and effective process to control the regeneration reaction and process while maintaining a stable dynamic sulfur capacity. A membrane-based process and system is described for producing regeneration and purge gas for the desulfurization.