Reformer Fuel Flexibility in Direct Reduced Iron Production
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Solution Overview
Problem
Conventional reformers in direct reduced iron (DRI) production operate within a narrow range of conditions, leading to reduced energy efficiency and syngas production when switching from natural gas to hydrogen as a fuel source, which also increases the risk of carbon deposition and catalyst damage.
Innovation Solution
Introducing preheated hydrogen gas directly into the hot feed gas, which is preheated using heat recovery systems before being introduced to the reformer, allows for continuous operation across a wide range of fuel sources from 100% natural gas to 100% hydrogen, maintaining high energy efficiency and preventing carbon deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional reformers operate within a narrow range of conditions optimized for natural gas, then natural gas reforming efficiency is maintained, but energy efficiency and syngas production decrease when switching to hydrogen fuel
Solution Approach 1:
The reformer system is designed with dynamic control capabilities that adjust operating parameters (temperature, pressure, gas flow rates, steam-to-carbon ratio) in real-time based on the fuel source being used. This allows the reformer to optimize performance whether running on natural gas, hydrogen, or mixed fuels, resolving the contradiction between adaptability and productivity.
Solution Approach 2:
The system changes key operating parameters when transitioning between fuel types. For hydrogen reforming, parameters such as temperature profiles, residence time, and steam injection rates are adjusted to match hydrogen's different combustion characteristics and reforming kinetics, thereby maintaining high syngas production across different fuel sources.
2Adaptability or versatility
If conventional reformers operate within a narrow range of conditions optimized for natural gas, then natural gas reforming efficiency is maintained, but energy efficiency decreases when switching to hydrogen fuel
Solution Approach 1:
The reformer system dynamically adjusts operating parameters based on the fuel source being used. When switching to hydrogen, the system optimizes temperature profiles, pressure settings, and gas flow rates to match hydrogen's higher flame speed and different heating value, thereby maintaining high energy efficiency across different fuel types.
Solution Approach 2:
Key operating parameters are changed when transitioning to hydrogen reforming, including temperature control, residence time, and steam-to-carbon ratio adjustments. These parameter changes ensure that the reforming process operates at optimal efficiency whether using natural gas or hydrogen as the fuel source.
3Adaptability or versatility
If conventional reformers operate within a narrow range of conditions, then stable operation with natural gas is achieved, but the risk of carbon deposition and catalyst damage increases when using hydrogen
Solution Approach 1:
The system takes preliminary actions to prevent carbon deposition before it occurs. When hydrogen is introduced as a fuel source, the system pre-adjusts operating parameters such as increasing steam injection rates and optimizing temperature profiles to create conditions that prevent carbon formation, thereby protecting the catalyst from damage.
Solution Approach 2:
Operating parameters are specifically adjusted when using hydrogen to prevent carbon deposition. The system increases steam-to-carbon ratios, optimizes temperature distributions, and adjusts residence times to ensure complete combustion and prevent carbon formation, thereby eliminating the harmful effect of carbon deposition and catalyst damage.
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 the energy efficiency and operational flexibility of DRI production, reduces the risk of carbon deposition and catalyst damage, and allows for the production of high-quality syngas, even when using hydrogen as a primary fuel source.
Implementation Method 1
the feed gas is preheated prior to the reformer using heat recovery (HR)
Implementation Method 2
CNH2N+2 in the feed gas 7 is reformed into CO and H2 using H2O and CO2
Implementation Method 3
NH2O+CNH2N+2→(2N+1)H2+NCO (endothermic reaction)
Data Source
AI summary
A method and system for producing synthesis gas for the production of direct reduced iron in a direct reduction shaft furnace, including: preheating cold feed gas in a heater to form hot feed gas; adding preheated external hydrogen gas to the hot feed gas downstream of the heater; feeding the hot feed gas and the preheated external hydrogen added to the hot feed gas to a reformer; and reforming the hot feed gas and the preheated external hydrogen added to the hot feed gas in the reformer to form the synthesis gas. The method and system also include feeding the synthesis gas to a bustle of the direct reduction shaft furnace for the production of the direct reduced iron in the direct reduction shaft furnace. The method may include adding preheated external hydrogen gas to the synthesis gas downstream of the reformer and upstream of the direct reduction shaft furnace.