Autothermal Reactor and Gas-Fired Reformer Integration for Hydrogen Production
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing processes for producing hydrogen from ammonia are inefficient, particularly in terms of energy usage and oxygen requirements, and often necessitate steam generation with limited economic benefit.
Innovation Solution
The proposed process utilizes an autothermally operable cracking reactor connected in parallel or series with a gas-fired reformer, allowing the hot cracked gas to be used for heating the reformer, thereby optimizing energy use and reducing oxygen and steam requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ammonia is cracked at high temperature and low pressure, then hydrogen production efficiency is improved, but pressure requirements increase leading to higher compression costs
Solution Approach 1:
The patent changes the operating parameters by implementing a two-stage cracking process with intermediate cooling. The first stage operates at high temperature for efficient cracking, then the gas is cooled and subjected to a second cracking stage. This parameter variation allows maintaining high hydrogen production efficiency while operating at more favorable pressure conditions, reducing compression requirements.
2Loss of energy
If steam is generated from hot cracked gas, then energy recovery is improved, but economic benefit is limited due to low steam demand in ammonia cracking
Solution Approach 1:
Instead of extracting steam from the hot cracked gas for energy recovery, the patent extracts and utilizes the hot cracked gas directly for process heating requirements. The hot gas from the first cracking stage is used to provide thermal energy for ammonia vaporization and preheating, directly addressing the energy needs of the process without the intermediate step of steam generation, thereby improving economic efficiency.
3Use of energy by moving object
If an autothermally operated reactor is used for ammonia cracking, then energy self-sufficiency is improved, but oxygen consumption increases
Solution Approach 1:
The patent implements a continuous two-stage cracking process where the hot cracked gas from the first stage continuously provides heat for ammonia vaporization and preheating. This continuous utilization of thermal energy creates a self-sustaining thermal cycle that maintains energy self-sufficiency throughout the process, allowing controlled oxygen consumption while achieving autonomous energy operation.
4Loss of energy
If a gas-fired reformer is connected in parallel with the autothermal reactor, then energy efficiency is improved, but plant complexity increases
Solution Approach 1:
The patent merges the autothermal reactor and gas-fired reformer into an integrated system where they operate in parallel but share common process streams. The hot cracked gas from the autothermal reactor is utilized by the reformer, and both units contribute to the overall hydrogen production. This merging approach achieves superior energy efficiency while managing plant complexity through integrated design rather than separate independent systems.
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 enhances the cold gas efficiency of the process, reduces the need for oxygen and steam, and simplifies plant design, while also increasing hydrogen yield.
Implementation Method 1
The reactions taking place in an AT reactor during ammonia decomposition are described by the following equations: 2 NH3 + O2 → 2 H2O + N2 + H2
Implementation Method 2
The cracking reaction is endothermic and is favored by low pressure and high temperature
Implementation Method 3
the heat of the AT cracked gas can be used for the reactions taking place within the GHR
Implementation Method 4
a cracking reactor (also known as an ammonia cracker) similar to a steam reformer, which is associated with pressure swing adsorption for hydrogen purification
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a method and a plant (100) for producing a hydrogen-containing product (6), wherein an ammonia-containing feedstock (2) is reacted in a cracking device (20) to obtain a cracked gas (3) containing unreacted ammonia, hydrogen, and nitrogen, from which the hydrogen-containing product (6) is formed. Characteristic here is that, in the cracking device (20), a hot cracked gas (2a) is generated from the ammonia-containing feedstock (2) with the aid of an autothermally operated reactor (AT reactor) (20a), and this hot cracked gas is used to heat a gas-fired reformer (GHR) (20b).