A process for co-production of ammonia, urea and methanol
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Solution Overview
Problem
Existing processes for co-producing ammonia, urea, and methanol from syngas often face inefficiencies and high costs, particularly in managing CO2 balance and optimizing syngas production, leading to excess CO2 and increased construction requirements.
Innovation Solution
A process integrating an autothermal reformer (ATR) and a steam methane reformer (SMR) in parallel, combined with an air separation unit (ASU) for nitrogen integration and CO2 optimization, allowing for simultaneous production of ammonia, urea, and methanol by adjusting syngas distribution between methanol and urea synthesis units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single steam methane reformer (SMR) is used for syngas production, then the process is simple, but it cannot optimize CO2 balance for simultaneous ammonia and urea production
Solution Approach 1:
The single reformer is segmented into two parallel reformers: an SMR for ammonia production and an ATR for urea production. This segmentation allows independent optimization of CO2 balance for each product stream while maintaining overall process efficiency.
Solution Approach 2:
The reformer system is designed with multi-functionality to serve dual purposes: producing syngas for ammonia synthesis and generating CO2-rich syngas for urea synthesis. The parallel configuration enables the system to fulfill multiple functions simultaneously.
2Productivity
If CO2 is removed from syngas for ammonia production, then ammonia synthesis efficiency improves, but urea production is limited by insufficient CO2
Solution Approach 1:
The syngas production is segmented into two parallel streams: one from SMR optimized for ammonia production with efficient CO2 removal, and another from ATR optimized for urea production with retained CO2. This resolves the conflict between ammonia efficiency and CO2 availability for urea.
Solution Approach 2:
The ATR acts as an intermediary source, providing CO2-rich syngas specifically for the urea synthesis unit, thereby mediating the CO2 distribution between ammonia and urea production streams.
3Adaptability or versatility
If parallel SMR and ATR are used for flexible product ratios, then production versatility improves, but process complexity and construction costs increase
Solution Approach 1:
The plant is segmented into modular parallel units (SMR and ATR) that can be independently adjusted to achieve different product ratios, providing flexibility without requiring complete process redesign.
Solution Approach 2:
The process configuration is made dynamic by allowing flexible adjustment of feed distribution between SMR and ATR, enabling the plant to adapt product ratios according to market demands while maintaining a relatively simple base configuration.
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 reduces overall costs, enables larger capacity co-production units, optimizes CO2 balance, and avoids excess CO2 production, allowing for flexible product ratios of methanol and urea while maintaining efficient ammonia synthesis.
Implementation Method 1
the conversion of a hydrocarbon feedstock, in this case natural gas, is carried out in a single reactor through the combination of partial combustion and adiabatic steam reforming
Implementation Method 2
Steam reforming of the partially combusted hydrogen feedstock is subsequently conducted in a fixed bed of a steam reforming catalyst
Implementation Method 3
feeding air to an air separation unit (ASU), where the air is split into oxygen, which is fed to the ATR, and nitrogen
Implementation Method 4
hydrogen is converted to ammonia upon addition of nitrogen
Implementation Method 5
removing the carbon dioxide from the synthesis gas from step (c)
Data Source
Figure 1
AI summary
A process for co-production of ammonia, urea and methanol from natural gas, comprising the steps of (a) producing a synthesis gas by simultaneous feeding natural gas to an au-tothermal reformer (ATR) and to a steam methane reformer (SMR), the two reformers running in parallel, (b) feeding air to an air separation unit (ASU), where the air is split into oxygen, which is fed to the ATR, and nitrogen, (c) subjecting the synthesis gas from the SMR to a water gas shift, (d) removing the carbon dioxide from the synthesis gas from step (c) and leading it to urea synthesis in a urea synthesis unit, (e) combining the hydrogen-rich gas from step (d) with the nitrogen from step (b), removing catalyst poisons from the gases and leading the gas mixture to ammonia synthesis in an ammonia synthesis unit, (f) optionally removing part of the carbon dioxide from the syngas from the ATR in step (a) and leading it to urea synthesis in a urea synthesis unit and (g) leading the syngas from step (f) to the methanol synthesis unit, wherein synthesis gas from step (a) may be led either from the ATR outlet to the SMR outlet upstream from the shift stage or the other way.