Desulfurization Process Combining Suspension and Fixed Beds
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Solution Overview
Problem
Existing desulfurization processes, particularly fluidized beds, suffer from low efficiency, complex operations, high costs, and secondary pollution, failing to meet industrial requirements for small and medium-sized projects.
Innovation Solution
A desulfurization process combining a suspension bed and a fixed bed, where a desulfurization slurry is mixed with hydrogen sulfide-containing gas, passed through a suspension bed for initial desulfurization, and then further purified in a fixed bed, using amorphous iron oxide hydroxide as the desulfurizer, with flash evaporation and regeneration to produce elemental sulfur.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If a fluidized bed is used for desulfurization, then the desulfurizer can be circulated and reused, but the gas-solid contact becomes nonuniform and desulfurization efficiency decreases
Solution Approach 1:
The patent applies dynamics by transitioning from a static fixed bed to a dynamic suspension bed system where the slurry is continuously circulated. The suspension bed allows the desulfurization slurry to be pumped from the bottom, flow through the reaction zone, and be regenerated continuously, creating a dynamic system that maintains high desulfurization efficiency while enabling desulfurizer circulation and reuse.
Solution Approach 2:
The patent changes the physical state parameters of the desulfurizer from dry solid particles to a slurry form (suspension). This parameter change allows the desulfurizer to be pumped and circulated like a fluid while maintaining its chemical desulfurization function. The slurry form enables continuous circulation through the suspension bed reactor and regeneration system, resolving the contradiction between desulfurizer utilization and desulfurization efficiency.
2Productivity
If lime slurry is directly used as desulfurizer, then desulfurization can be achieved, but mortar pipelines foul and clog and flow resistance increases
Solution Approach 1:
The patent uses a suspension bed system where the desulfurization slurry has a controlled residence time (5-60 minutes) in the reactor before being discharged for regeneration. This approach allows the slurry to be used effectively for desulfurization and then regenerated, avoiding pipeline fouling by limiting the time the slurry spends in transport pipelines. The system effectively treats the slurry as a short-living medium that is continuously renewed.
3Productivity
If wet desulfurization methods are used, then large treatment capacity is achieved, but secondary sewage problems occur
Solution Approach 1:
The patent implements a regeneration system where the desulfurization slurry is continuously regenerated after use. The spent slurry is separated from the gas stream, and the desulfurizer components are recovered and regenerated for reuse. This discarding of spent slurry and recovering of desulfurizer materials eliminates the accumulation of sulfur-containing waste liquids that would otherwise become secondary sewage pollution.
Solution Approach 2:
The regeneration process uses oxidation to convert the sulfur compounds captured in the slurry back into elemental sulfur or sulfate forms that can be separated. This oxidation process (using air or oxygen) transforms the harmful dissolved sulfur compounds into separable solid or easily removable forms, preventing secondary sewage pollution while maintaining large gas treatment capacity.
4Manufacturing precision
If dry desulfurization is used, then operation is simple and reliable with high desulfurization degree, but it is only suitable for low hydrogen sulfide content gas
Solution Approach 1:
The patent creates a multi-functional system that combines the advantages of both dry and wet desulfurization. The suspension bed can operate with slurry concentrations and flow rates that adapt to different hydrogen sulfide content levels. The system can handle both low concentration gases (achieving high desulfurization degree like dry methods) and high concentration gases (with large treatment capacity like wet methods) by adjusting operational parameters, thus achieving universality across different gas compositions.
Data Source
AI summary
A desulfurization process which uses both a suspension bed and a fixed bed is disclosed herein. In particular, the desulfurization slurry is mixed with a hydrogen sulfide containing gas to obtain a first mixture, and the first mixture passed into a suspension bed reactor from bottom to top, while controlling the first mixture to have a dwell time of 5-60 minutes in the reactor. A second mixture obtained by the reaction is subjected to gas liquid separation to produce a gas phase, and the gas phase is feed into a fixed bed reactor for a second desulfurization which produces purified gas. Advantageously, sulfur content in the hydrogen sulfide containing gas may be reduced from 2.4-140 g/Nm3 to 50 ppm or less by using a suspension bed, and the sulfur content may be even further reduced to less than 10 ppm in conjunction with a fixed bed.