Catalytic H2S and Ammonia Cracking for Hydrogen Recovery
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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 ammonia handling, leading to increased emissions and equipment size.
Innovation Solution
The process involves catalytic oxidative cracking of H2S and ammonia in the same reaction chamber, using an oxygen-enriched gas stream with a catalyst like Pt, Rh, or Mo-based catalysts to promote H2S dissociation and partial oxidation, reducing nitrogen oxide formation and enhancing hydrogen production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If traditional Claus process is used for sulphur recovery, then sulphur can be recovered from H2S-containing gas streams, but hydrogen production is limited and equipment size is large
Solution Approach 1:
The patent combines sulphur recovery and hydrogen production into a single integrated process. The catalytic reactor simultaneously performs H2S conversion to sulphur and generates hydrogen through controlled dissociation and water-gas shift reactions, eliminating the need for separate hydrogen production units and reducing overall equipment footprint
Solution Approach 2:
The catalytic reactor system performs multiple functions: H2S decomposition, sulphur condensation, hydrogen production via water-gas shift reaction, and CO conversion. This multi-functional approach replaces traditional separate units for each function, achieving both sulphur recovery and hydrogen generation in one system
2Object-generated harmful factors
If traditional Claus process with ammonia destruction is used, then ammonia can be destroyed in the Claus section, but nitrogen oxide emissions increase and sulphur recovery efficiency decreases
Solution Approach 1:
The patent changes the operating parameters by using catalytic reactors with specific temperature zones (300-500°C for first reactor, 200-400°C for second reactor) and controlled H2S/O2 ratios. These parameter changes enable selective reactions that convert ammonia to nitrogen and water without forming nitrogen oxides, while simultaneously maintaining high sulphur recovery efficiency through optimized catalytic conditions
Solution Approach 2:
The patent introduces controlled oxygen injection (0.5-2.0 mol% O2 in feed gas) to accelerate the oxidation of H2S and ammonia. This controlled oxidation promotes complete conversion of ammonia to nitrogen and water rather than nitrogen oxides, while the catalytic surfaces facilitate selective reaction pathways that maintain high sulphur recovery
3Quantity of substance
If sub-stoichiometric combustion is used in thermal reactor, then H2S can be oxidized to SO2 for Claus reaction, but hydrogen production is minimal and energy efficiency is low
Solution Approach 1:
The patent replaces the thermal combustion-based H2S conversion with catalytic conversion systems. The catalytic reactors operate at lower temperatures (300-500°C) compared to thermal combustion, reducing energy input requirements while simultaneously producing hydrogen through water-gas shift reactions. This substitution of catalytic mechanism for thermal mechanism improves both hydrogen production and energy efficiency
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 method achieves higher hydrogen yield, reduces SO2 formation, and minimizes equipment size by efficiently converting H2S and ammonia, producing a valuable hydrogen export stream while minimizing atmospheric emissions.
Implementation Method 1
catalytic oxidative cracking of H2S and ammonia in the same reaction chamber, using an oxygen-enriched gas stream with a catalyst like Pt, Rh, or Mo-based catalysts to promote H2S dissociation and partial oxidation
Implementation Method 2
promote H2S dissociation and partial oxidation
Implementation Method 3
promote H2S dissociation and partial oxidation
Data Source
AI summary
Disclosed is a method for the production of hydrogen from a H2S-containing gas stream also containing ammonia, comprising subjecting both gas stream to catalytic oxidative cracking of both the H2S and the NH3, so as to form H2, S2 and N2. In this method, preferably, an additional amount of oxygen is added as compared to the amount used for H2S catalytic oxidative cracking. Also, preferably, the contact time of the gas stream with the catalyst is increased. The catalyst preferably is provided as a single bed, and then preferably comprises iron and molybdenum supported by a carrier comprising aluminum. The preferred carrier is alumina. The iron and molybdenum preferably are in the form of sulfides.