Gas Purification Device for Carbonyl Sulfide Reduction
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Solution Overview
Problem
Conventional gas clean-up units struggle to effectively reduce carbonyl sulfide concentrations in coal gasification gas, especially when concentrations are high, due to reversible hydrolysis reactions and trace component deposition issues at low temperatures.
Innovation Solution
A multi-step process involving a first conversion unit that converts hydrogen cyanide and carbonyl sulfide to hydrogen sulfide at specific temperatures, followed by a cleaning unit to remove ammonia and halogen traces, and a desulfurization unit to absorb hydrogen sulfide, ensuring effective reduction of carbonyl sulfide concentrations through controlled temperature and catalyst usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the reaction temperature for hydrolyzing carbonyl sulfide is lowered to improve conversion efficiency, then carbonyl sulfide reduction is enhanced, but trace components such as ammonia, halogen, and hydrocarbon are deposited
Solution Approach 1:
The gas purification process is divided into multiple stages: a first conversion unit operates at higher temperature (240-350°C) to convert hydrogen cyanide to ammonia and perform initial carbonyl sulfide hydrolysis, followed by a second conversion unit operating at lower temperature (150-240°C) to complete carbonyl sulfide conversion. This segmentation allows each unit to operate in its optimal temperature range, achieving both high conversion efficiency and preventing trace component deposition.
2Object-generated harmful factors
If the reaction temperature is raised to prevent trace component deposition, then deposition is avoided, but carbonyl sulfide conversion efficiency decreases
Solution Approach 1:
The conversion process is segmented into two temperature zones: the first conversion unit operates at 240-350°C to prevent deposition while performing initial conversion, and the second conversion unit operates at 150-240°C to maximize carbonyl sulfide conversion efficiency. This multi-stage approach resolves the temperature contradiction by applying different temperature conditions at different process stages.
Solution Approach 2:
The first conversion unit performs preliminary carbonyl sulfide hydrolysis at higher temperature to convert a portion of carbonyl sulfide and reduce the load on the second conversion unit. This preliminary action allows the second unit to operate at lower temperature with better conversion efficiency, as the carbonyl sulfide concentration entering the second unit is already reduced.
3Device complexity
If a single conversion unit is used to simplify the process, then device complexity is reduced, but carbonyl sulfide concentration cannot be reduced to desired levels when initial concentration is high
Solution Approach 1:
The system uses two conversion units in series, where the first unit performs initial carbonyl sulfide hydrolysis and the second unit completes the conversion. This segmentation enables the system to handle high initial carbonyl sulfide concentrations (≥1000 ppm) effectively, achieving desired reduction levels that would be difficult with a single unit.
4Productivity
If the hydrolysis reaction is performed at low temperature to improve equilibrium conversion, then carbonyl sulfide reduction is enhanced, but the reaction rate decreases
Solution Approach 1:
The process segments the hydrolysis reaction into two stages with different temperature conditions. The first conversion unit operates at higher temperature (240-350°C) to maintain fast reaction rate, while the second conversion unit operates at lower temperature (150-240°C) to achieve better equilibrium conversion. This segmentation resolves the contradiction between reaction rate and equilibrium conversion.
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 prevents trace component deposition and efficiently reduces carbonyl sulfide concentrations in coal gasification gas, even at high initial concentrations, by utilizing two-step conversion and cleaning processes, thereby enhancing gas purification efficiency.
Implementation Method 1
carbonyl sulfide contained in the coal gasification gas is hydrolyzed to hydrogen sulfide and carbon dioxide by the hydrolysis reaction represented by the following reaction formula (1). COS + H2O ⇔ H2S + CO2
Implementation Method 2
a first conversion unit configured to perform a first conversion process of converting hydrogen cyanide contained in coal gasification gas to ammonia, and converting carbonyl sulfide contained therein to hydrogen sulfide in presence of a first catalyst
Implementation Method 3
a second conversion unit configured to perform a second conversion process of converting carbonyl sulfide remained in the gas coal gasification gas that has been subjected to the first conversion process to hydrogen sulfide, in presence of a second catalyst
Implementation Method 4
converting carbonyl sulfide remained in the gas coal gasification gas that has been subjected to the first conversion process to hydrogen sulfide, in presence of a second catalyst
Implementation Method 5
a cleaning unit configured to perform a cleaning process of bringing the coal gasification gas into gas-liquid contact with cleaning liquid to remove ammonia, halogen and hydrocarbon traces by cleaning
Implementation Method 6
a desulfurization unit configured to absorb and remove hydrogen sulfide in the coal gasification gas by bringing the coal gasification gas that has been subjected to the cleaning process into gas-liquid contact with absorbent
Data Source
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AI summary
To provide a gas clean-up unit and a gas purification method that can effectively reduce the concentration of carbonyl sulfide in gas to be treated even when the concentration of carbonyl sulfide in the gas to be treated is high. A gas clean-up unit 1 includes a first COS converter 12 that performs a first conversion process of converting hydrogen cyanide contained in gas to be treated G1 to ammonia, in presence of a first catalyst and at a first predetermined temperature; a second COS converter 14 that performs a second conversion process of converting carbonyl sulfide in gas to be treated G3 after the first conversion process to hydrogen sulfide, in presence of a second catalyst and at a second predetermined temperature that is lower than the first predetermined temperature; a first cleaner 13 that performs a cleaning process of cleaning and removing ammonia by bringing gas to be treated G2 into gas-liquid contact with cleaning liquid; and a desulfurizer 16 that absorbs and removes hydrogen sulfide in gas to be treated G5 by bringing the gas to be treated G5 after the cleaning process into gas-liquid contact with absorbent.