Catalytic Urea Synthesis via Formamide Intermediates
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Solution Overview
Problem
Conventional processes for urea production face challenges such as high capital costs due to the use of expensive corrosion-resistant steel and harsh high-pressure and temperature conditions, as well as low yields and catalyst deactivation in catalytic synthesis methods using carbon dioxide.
Innovation Solution
A process involving the catalytic synthesis of urea using formamide as an intermediate, produced from carbon dioxide, hydrogen, and ammonia, with methyl formate or ammonium formate as intermediates, utilizing a methanol phase or aqueous ammonia solution loaded with chemically or physically bound carbon dioxide, allowing for minimal intervention in existing ammonia synthesis processes and efficient reuse of hydrogen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional high-pressure synthesis method is used, then urea production is achieved, but capital costs increase due to expensive corrosion-resistant steel and harsh process conditions
Solution Approach 1:
The invention changes the reaction parameters from high pressure (150 bar) and high temperature (180°C) to mild pressure (5-20 bar) and mild temperature (60-100°C) conditions, enabling the use of standard stainless steel instead of expensive corrosion-resistant steel like Safurex®, thereby significantly reducing capital costs while maintaining urea production capability
Solution Approach 2:
The invention introduces formamide as an intermediary substance in a two-step process: first converting CO2 to formamide, then converting formamide to urea. This intermediary approach avoids the direct high-pressure CO2 + 2NH3 reaction, enabling milder process conditions and reduced equipment costs
2Ease of manufacture
If catalytic synthesis using carbon dioxide is used, then capital costs are reduced, but yields are low and catalyst deactivation occurs
Solution Approach 1:
The invention uses formamide as an intermediary that stabilizes the reaction process, preventing direct catalyst contact with CO2 and NH3 mixture, thereby maintaining high yields and preventing catalyst deactivation while still achieving cost reduction through milder conditions
Solution Approach 2:
The invention segments the single-step catalytic reaction into two separate steps: (1) CO2 to formamide conversion, and (2) formamide to urea conversion. This segmentation allows optimization of each step independently, improving overall yield and catalyst stability
3Productivity
If conventional high-pressure process is used, then urea synthesis is achieved, but equipment costs increase due to high-pressure and high-temperature requirements
Solution Approach 1:
The invention fundamentally changes the process parameters from high-pressure/high-temperature regime to mild-pressure/mild-temperature regime, allowing the use of standard stainless steel equipment instead of specialized high-pressure equipment, thereby reducing equipment costs while maintaining urea synthesis productivity
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 capital costs, minimizes process modifications, and achieves higher yields by using readily available feedstocks, with the ability to recover hydrogen for reuse, thus enhancing the economic and operational efficiency of urea production.
Implementation Method 1
gas scrubbing of a synthesis gas to remove CO2 using a washing liquid, whereby the washing liquid is a methanol phase or the CO2 is desorbed from the chemically and/or physically bound carbon dioxide-laden washing liquid
Implementation Method 2
CO2 is at least partially bound in the washing liquid in the form of carbonates
Implementation Method 3
production of urea by reacting the formamide formed or the formamide formed with ammonia in the presence of a catalyst
Data Source
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AI summary
The invention relates to a method for producing urea, comprising: a) producing formamide on the basis of carbon dioxide, hydrogen and ammonia, wherein methyl formate or ammonium formate is formed as an intermediate product in a catalytic reaction; and b) producing urea by reacting the formed formamide or the formed formamide in combination with ammonia in the presence of a catalyst, wherein the source for carbon dioxide is a fluid laden with chemically and/or physically bonded carbon dioxide, selected from a methanol phase or an aqueous ammonia solution, which is obtained by scrubbing a syngas in order to remove CO 2 using a scrubbing fluid. The method according to the invention can be coupled with an ammonia synthesis, wherein only minor modifications are required in the ammonia synthesis process.