Integrated Sulfur Recovery and Hydrogen Production via Acid Gas Combustion
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Solution Overview
Problem
Current sulfur recovery technologies face challenges in efficiently producing hydrogen and reducing CO2 and SO2 emissions, particularly due to high fuel consumption and instability in processing acid gases with varying compositions, and they do not effectively utilize acid gas burner incineration without fuel to achieve complete combustion.
Innovation Solution
The integration of the Sulfur-Iodine (S-I) thermochemical cycle, where acid gases are combusted with excess air/oxygen in an acid gas burner to produce SO2 and hydrogen, using iodine to facilitate hydrogen production and reduce emissions, and the subsequent conversion of SO2 to sulfuric acid or fertilizer products, thereby minimizing fuel usage and emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If acid gases are processed in conventional Claus sulfur recovery units, then sulfur recovery is achieved, but hydrogen production is limited and fuel consumption is high
Solution Approach 1:
The patent combines the Claus sulfur recovery process with a sulfuric acid production unit and a hydrogen production unit into an integrated system. The SO2 generated from acid gas combustion is fed to the sulfuric acid unit, while simultaneously utilizing the combusted gas stream for hydrogen production through water-gas shift reactions, thereby achieving multiple products from a single feed stream and reducing overall fuel consumption.
Solution Approach 2:
The combustion unit serves multiple functions: it converts H2S to SO2 for sulfur recovery, generates heat for the overall process, and provides a gas stream containing CO and H2 that can be further processed for hydrogen production. This multi-functionality reduces the need for separate fuel sources and increases hydrogen yield.
2Reliability
If excess air/oxygen is used in acid gas burner incineration, then complete combustion to produce SO2 is achieved, but CO2 emissions increase
Solution Approach 1:
The patent converts the harmful CO2 generated from complete combustion into a useful resource by feeding the CO-containing gas stream into the hydrogen production unit where water-gas shift reactions convert CO and H2O into additional H2 and CO2. The CO2 is then separated and can be utilized or sequestered, thereby converting a waste product into a valuable resource while maintaining complete combustion efficiency.
Solution Approach 2:
Instead of discarding the CO2 generated during combustion, the system recovers it through the hydrogen production process and subsequent separation units. The CO2 is captured and can be used for enhanced oil recovery, chemical synthesis, or sequestration, thereby reducing net emissions while maintaining the benefits of complete combustion.
3Adaptability or versatility
If acid gases with varying compositions are processed, then flexibility in handling different feedstocks is achieved, but process stability deteriorates
Solution Approach 1:
The patent incorporates dynamic control systems that automatically adjust process parameters such as air-to-fuel ratio, catalyst temperature, and flow rates based on real-time analysis of acid gas composition. This dynamic adaptation allows the system to maintain optimal performance and stability even when feedstock composition varies significantly, accommodating different types of acid gases from various sources.
Solution Approach 2:
The system employs online sensors and analyzers to continuously monitor the composition of the acid gas feed and the intermediate streams. This information is fed back to the control system, which adjusts operating conditions to maintain process stability and optimize hydrogen production, thereby handling variable feedstocks effectively without compromising process reliability.
4Productivity
If sulfur recovery is integrated with hydrogen production, then hydrogen quantity increases, but process complexity increases
Solution Approach 1:
The integrated system is divided into distinct functional modules: an acid gas combustion unit, a sulfuric acid production unit, and a hydrogen production unit with separate reaction zones for water-gas shift and methanation. This segmentation allows each unit to be optimized independently while maintaining overall integration, making the complex process more manageable and easier to operate.
Solution Approach 2:
The patent uses intermediate streams and buffer zones to connect the different process units. For example, the SO2 stream serves as an intermediary between the combustion unit and sulfuric acid unit, while the CO-containing gas stream acts as an intermediary between combustion and hydrogen production. These intermediaries facilitate smooth material flow and reduce direct interactions that would increase complexity.
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 significantly reduces energy and fuel consumption, lowers CO2 and SO2 emissions, and produces a substantial quantity of hydrogen, making it economically viable and environmentally friendly for industrial applications.
Implementation Method 1
the acid gases containing H2S and the sulfur compounds that is normally processed in the Claus unit, now to produce SO2... the acid gas burner incineration unit where H2S and all other sulfur compounds and ammonia, hydrocarbons in the feed reacts with excess air/oxygen to produce SO2
Implementation Method 2
H2S+3/2O2→SO2+H2O
Implementation Method 3
produce large quantity of H2 VIA the phenomena of the Sulfur-Iodine (S-I) thermochemical cycle
Implementation Method 4
2H2O+SO2+I2→H2SO4+2HI
Implementation Method 5
The combusted gas stream is then sent to two waste heat boilers to cool the stream and produce steam
Data Source
AI summary
H2 production, sulfuric acid and SO2 production process refers to an innovative process VIA the phenomena of the Sulfur-Iodine (S-I) thermochemical cycle. The process consist of the acid gas burner to burn all the acid gases with air, enriched air or oxygen and without using any fuel gas to produce SO2. The acid gases are normally processed in the prior arts of the sulfur recovery units. Iodine is used to produce the hydrogen.A portion or all of the acid gases are sent to the acid gas burner in accordance with the present invention.The present innovation not only produces hydrogen but also reduces the SO2 and CO2 emissions.The produced SO2 is sent to other units to produce other fertilizer products and the produced CO2 is sent to CO2 removal or CO2 Liquefaction process.The hydrogen is produced is used to supply the needs within the facility like hydrotreaters to reduce external import and to reduce the operating costs.