Sulfur-Fired Primary Reformer Heating With SO2-to-Acid Integration
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Solution Overview
Problem
Conventional ammonia production methods, particularly those using steam methane reforming (SMR), are energy-intensive and emit high levels of greenhouse gases due to the use of hydrocarbon fuels, necessitating a reduction in energy consumption and emissions to achieve sustainability.
Innovation Solution
An integrated system that substitutes hydrocarbon fuels in the primary reformer of an SMR-based ammonia plant with sulfur, utilizing a mixture of air and oxygen to burn sulfur, producing a sulfur dioxide-rich stream for sulfuric acid production, and recovering waste heat to generate power and steam, thereby reducing carbon emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If hydrocarbon fuels are used in the primary reformer of an SMR-based ammonia plant, then the reformer can be heated up to operating temperature, but high levels of greenhouse gases are emitted
Solution Approach 1:
The patent changes the fuel parameter from hydrocarbon-based to sulfur-based, fundamentally altering the combustion chemistry to eliminate CO2 emissions while maintaining the necessary heating temperature for the primary reformer operation
Solution Approach 2:
The patent converts the traditionally harmful SO2 emission from sulfur combustion into a valuable product by integrating a sulfuric acid production unit, transforming an environmental liability into an economic and environmental asset
2Object-generated harmful factors
If sulfur is burned as fuel in the primary reformer combustion zone, then carbon emissions are reduced, but combustion temperature control becomes more challenging
Solution Approach 1:
The patent implements a feedback control system where a portion of the cooled flue gas is recycled and mixed with the combustion air stream, allowing dynamic adjustment of combustion temperature based on process conditions and maintaining optimal temperature for sulfur combustion
Solution Approach 2:
The patent uses an asymmetric mixture of air and oxygen in the combustion zone, with oxygen enrichment to achieve more complete and efficient sulfur combustion while maintaining temperature control, creating an optimized combustion atmosphere that differs from conventional air-only combustion
3Use of energy by moving object
If an integrated system coupling ammonia and sulfuric acid production is implemented, then energy utilization is optimized, but system complexity increases
Solution Approach 1:
The patent merges two separate industrial processes (ammonia production and sulfuric acid production) into an integrated system where the sulfur combustion unit serves dual purposes: heating the primary reformer and generating SO2 for sulfuric acid production, thereby optimizing energy utilization and reducing overall system complexity through functional consolidation
Solution Approach 2:
The primary reformer combustion zone serves multiple functions: it heats the reformer tubes, generates high-pressure steam for power generation, and produces concentrated SO2 stream for sulfuric acid production, making the system highly efficient and reducing the need for separate dedicated units
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
The system significantly reduces carbon emissions by up to 30% compared to existing SMR plants, achieving low carbon ammonia production while optimizing energy utilization and integrating with sulfuric acid production.
Implementation Method 1
burning molten sulfur as fuel with a mixture of air and O2; producing an SO2-rich stream exiting the ammonia primary reformer combustion zone
Implementation Method 2
providing oxygen from an air separation unit to the combustion zone of a typical SMR based ammonia plant's primary reformer
Implementation Method 3
producing high pressure steam for use in typical SMR based ammonia plant, while excess steam can be used to generate power
Implementation Method 4
converting sulfur dioxide to sulfuric acid in a conventional sulfuric acid plant
Data Source
Figure 1
AI summary
A novel integrated system utilizing sulfur as alternative carbon-free fuel in an ammonia primary reformer combustion zone, with co-production of sulfuric acid from concentrated SO2 off-gas stream. Such integration shall reduce hydrocarbon fuel consumption, minimize CO2 emissions, and optimize overall energy utilization.