Carbonyl Sulfide Removal in Hydrocarbon Streams via Prewash Integration
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Solution Overview
Problem
Current sulfur removal processes in hydrocarbon streams are costly and inflexible, requiring multiple equipment pieces and limited to a single solvent, with carbonyl sulfide removal systems causing solvent carryover and upsetting downstream units.
Innovation Solution
A process and apparatus that combine a gas phase hydrocarbon stream with an alkali and alkanolamine stream, using a prewash zone with trays and coated mesh to remove carbonyl sulfide in the pretreatment section, reducing equipment needs and allowing solvent flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If carbonyl sulfide removal systems are added to post treatment section, then carbonyl sulfide can be removed, but equipment complexity increases and solvent carryover occurs
Solution Approach 1:
The patent combines carbonyl sulfide removal with the existing mercaptan extraction process by integrating a carbonyl sulfide solvent system into the pretreatment section. The carbonyl sulfide solvent contacts the hydrocarbon stream in the same extraction unit where mercaptan removal occurs, eliminating the need for separate post-treatment carbonyl sulfide removal equipment and valve trays.
Solution Approach 2:
The patent performs carbonyl sulfide removal in the pretreatment section before the hydrocarbon stream enters downstream processing units. By removing carbonyl sulfide early in the process flow, the system prevents solvent carryover into downstream units and eliminates the need for complex post-treatment carbonyl sulfide removal systems.
2Reliability
If multiple equipment pieces are used for carbonyl sulfide removal, then carbonyl sulfide can be removed, but process cost increases
Solution Approach 1:
The patent merges carbonyl sulfide removal functionality into the existing mercaptan extraction unit by adding a carbonyl sulfide solvent system. This integration eliminates the need for separate equipment such as carbonyl sulfide removal valve trays and dedicated post-treatment sections, thereby reducing capital investment and operational costs.
Solution Approach 2:
The extraction unit is designed to perform multiple functions simultaneously: mercaptan extraction, carbonyl sulfide removal, and pretreatment of the hydrocarbon stream. The carbonyl sulfide solvent system serves dual purposes by removing both mercaptan and carbonyl sulfide compounds in a single pass, reducing the need for multiple specialized equipment pieces.
3Reliability
If carbonyl sulfide removal system is added, then carbonyl sulfide can be removed, but solvent carryover occurs upsetting downstream units
Solution Approach 1:
The patent removes carbonyl sulfide in the pretreatment section before the hydrocarbon stream enters downstream processing units. By performing carbonyl sulfide removal early in the process flow, the system prevents carbonyl sulfide and solvent carryover into downstream units, eliminating the harmful effects associated with post-treatment removal systems.
Solution Approach 2:
The patent changes the operational parameters by using a carbonyl sulfide solvent system with specific selectivity characteristics. The carbonyl sulfide solvent is chosen to have high affinity for carbonyl sulfide compounds while maintaining low solubility in the hydrocarbon phase, thereby achieving effective carbonyl sulfide removal with minimal solvent carryover into downstream units.
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 reduces costs by eliminating post-treatment valve trays, prevents solvent carryover, and allows for flexible solvent choices, expediting revamps by replacing prewash caustic with carbonyl sulfide solvent.
Implementation Method 1
combining the gas phase hydrocarbon stream with another stream including an alkali and an alkanolamine, and passing the combined stream to a prewash zone including a vessel
Implementation Method 2
the vessel contains a contacting zone and a coalescing zone for removing the carbonyl sulfide. Often, the vessel contains one or more trays and a coated mesh for removing at least one of the carbonyl sulfide and hydrogen sulfide
Data Source
AI summary
One exemplary embodiment can be a process for removing carbonyl sulfide in a gas phase hydrocarbon stream. The process may include combining the gas phase hydrocarbon stream with another stream including an alkali and an alkanolamine, and passing the combined stream to a prewash zone including a vessel. The gas phase hydrocarbon may include carbonyl sulfide, and the alkali can include at least one of potassium hydroxide, sodium hydroxide, and ammonia. Usually, the vessel contains a contacting zone and a coalescing zone for removing the carbonyl sulfide.