Two-Reactor H2S Scavenging System with Flow Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current hydrogen sulfide removal processes from natural gas are inefficient in utilizing scavenger reagents, leading to high overall process costs due to excessive reagent consumption and unreacted reagent disposal, particularly in smaller-scale operations.
Innovation Solution
A system comprising two reactors is used, where partially-consumed scavenging reagent reacts with sour natural gas in the first reactor, and clean scavenging reagent reacts with partially-sweetened gas in a second reactor, with a control system managing the flow of reagents based on hydrogen sulfide concentration to optimize reagent utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single reactor with scavenging reagent is used to remove hydrogen sulfide from natural gas, then the process is simpler and lower in capital cost, but the scavenging reagent is not fully utilized leading to higher operational costs and waste
Solution Approach 1:
The single reactor system is divided into two separate reactors: a first reactor where scavenging reagent reacts with sour natural gas to produce partially-sweetened gas, and a second reactor where additional scavenging reagent reacts with the partially-sweetened gas to produce fully sweetened gas. This segmentation allows for optimized reagent distribution and complete utilization of the scavenging reagent capacity.
Solution Approach 2:
The system changes the operational parameters by controlling the flow rates of scavenging reagent to each reactor based on the hydrogen sulfide concentration in the feed gas. The control system adjusts the distribution of scavenging reagent between the two reactors to ensure complete utilization of the reagent capacity while adapting to varying inlet conditions.
2Reliability
If excess scavenging reagent is used to ensure complete hydrogen sulfide removal, then the reliability of H2S removal is improved, but the cost of reagent consumption increases significantly
Solution Approach 1:
A control system continuously monitors the hydrogen sulfide concentration in the feed gas and adjusts the flow rates of scavenging reagent to the first and second reactors accordingly. This feedback mechanism ensures that the scavenging reagent is dosed optimally to achieve complete H2S removal without excessive reagent consumption, thereby maintaining reliability while reducing costs.
Solution Approach 2:
The first reactor performs a preliminary removal of hydrogen sulfide from the sour natural gas, producing partially-sweetened gas. This preliminary action reduces the H2S load before the gas enters the second reactor, allowing the scavenging reagent to be used more efficiently and completely in the second stage without requiring excessive amounts from the beginning.
3Productivity
If the scavenging reagent flow rate is increased to handle higher hydrogen sulfide concentrations, then the productivity of H2S removal is improved, but the reagent consumption and waste disposal costs increase
Solution Approach 1:
By dividing the treatment into two reactors with different functions, the system can handle varying H2S concentrations more efficiently. The first reactor handles the bulk removal at higher rates, while the second reactor ensures complete removal with optimized reagent dosing, thereby maintaining productivity without proportionally increasing reagent waste.
Solution Approach 2:
The control system dynamically adjusts the scavenging reagent flow rates to each reactor based on real-time measurements of H2S concentration in the feed gas. This dynamic adjustment allows the system to maintain high productivity when H2S levels are high while minimizing reagent waste when concentrations are lower, optimizing the balance between productivity and reagent utilization.
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 ensures complete utilization of the scavenger reagent, reducing costs by minimizing waste and lowering the process cost per unit of hydrogen sulfide removed, as demonstrated by a cost comparison showing significant annual savings.
Implementation Method 1
Hydrogen sulfide reacts with many metals cations to produce the corresponding metal sulfides
Implementation Method 2
a separator operatively connected to the first reactor for separating consumed scavenging reagent from the partially-sweetened natural gas
Data Source
AI summary
The invention describes a system and method for hydrogen sulfide decontamination of natural gas using a scavenging reagent. The system uses a scavenging reagent within two reactors wherein the consumption of scavenging reagent is optimized by the control of flow of clean and partially-consumed scavenging reagent within and between the two reactors.