Iron-Molybdenum Alumina Catalyst for H2S Cracking
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Solution Overview
Problem
Traditional Sulphur Recovery Plants face inefficiencies in sulphur recovery, emit pollutants, and require large equipment due to incomplete H2S conversion and the presence of impurities like ammonia and methane, which can lead to equipment blockage and emissions.
Innovation Solution
A catalyst composition of iron and molybdenum supported by aluminium is used for catalytic oxidative cracking of H2S-containing gas streams, promoting H2S dissociation and partial oxidation to produce hydrogen and sulphur, while minimizing SO2 formation and equipment size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional Claus process is used for sulphur recovery, then sulphur can be recovered from H2S-containing gas streams, but sulphur recovery efficiency is limited to 94-98% and further treatment is required
Solution Approach 1:
The patent changes the operating parameters by using a catalytic reactor with iron-molybdenum-aluminium catalyst operating at 850-950°C with a specific H2S/O2 ratio (2:1 to 6:1), enabling near-complete H2S conversion in a single stage and eliminating the need for multiple treatment stages
Solution Approach 2:
The invention extracts and removes the thermal stage from the traditional two-stage Claus process by implementing a single catalytic stage that performs both oxidation and cracking functions, simplifying the overall process configuration
2Productivity
If thermal reactor is used for H2S combustion, then sulphur can be recovered, but equipment size is large and residence time requirements are high
Solution Approach 1:
The patent replaces the thermal combustion system with a catalytic reaction system, where the iron-molybdenum-aluminium catalyst provides active sites for H2S oxidation and cracking, dramatically increasing reaction rate and reducing required reactor volume
Solution Approach 2:
The catalyst utilizes porous aluminium support material with high surface area, providing extensive active sites for catalytic reactions, which intensifies the reaction process and reduces the volume of reactor equipment needed
3Object-generated harmful factors
If ammonia and hydrocarbons are present in feedstock, then they can be destroyed in Claus section, but equipment blockage and emissions problems occur
Solution Approach 1:
The patent changes the chemical environment by operating at optimized temperature (850-950°C) and H2S/O2 ratio (2:1 to 6:1) that promote complete combustion and oxidation of ammonia and hydrocarbons to harmless products, preventing equipment blockage and emissions
Solution Approach 2:
The invention converts the harmful ammonia and hydrocarbon impurities into beneficial effects by using their combustion to provide additional heat for the endothermic H2S cracking reaction, while complete oxidation eliminates emissions and blockage problems
4Quantity of substance
If hydrogen is produced from H2S dissociation, then hydrogen can be recovered, but SO2 formation increases
Solution Approach 1:
The patent optimizes the H2S/O2 ratio (2:1 to 6:1) and temperature (850-950°C) to control the balance between H2S dissociation (producing H2) and oxidation (producing SO2), maximizing hydrogen production while minimizing SO2 formation through selective catalysis
Solution Approach 2:
The catalyst provides different active sites with different functions: some sites promote H2S dissociation to produce hydrogen, while other sites facilitate selective oxidation, creating local chemical environments that simultaneously achieve both objectives
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 enhances sulphur recovery efficiency, reduces emissions, and decreases hydrogen consumption, offering a more compact and efficient process for sulphur production with reduced environmental impact.
Implementation Method 1
catalytic oxidative cracking of H2S-containing gas streams, promoting H2S dissociation and partial oxidation to produce hydrogen and sulphur
Implementation Method 2
promoting H2S dissociation and partial oxidation to produce hydrogen and sulphur, while minimizing SO2 formation
Data Source
AI summary
Disclosed is a catalyst suitable for the catalytic oxidative cracking of a H2S-containing gas stream, particularly in the event that the stream also contains methane and/or ammonia. The catalyst comprises iron and molybdenum supported by a carrier comprising aluminium. The carrier preferably is alumina. The iron and molybdenum preferably are in the form of sulphides. Also disclosed is a method for the production of hydrogen from a H2S-containing gas stream, comprising subjecting the gas stream to catalytic oxidative cracking so as to form H2 and S2, using a catalyst in accordance with any one of the preceding claims.