Catalytic Purification of CO2 Streams from Ammonia-Urea Plants
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Solution Overview
Problem
Integrated ammonia-urea plants face contamination issues with hydrogen and methanol in the carbon dioxide feed, which are detrimental to urea synthesis, leading to equipment fouling and safety concerns, and existing methods require complex equipment and high water consumption.
Innovation Solution
A method using a single catalytic reactor with a platinum- or palladium-based catalyst to oxidize hydrogen to water and methanol to carbon dioxide, reducing contaminants to low ppm levels in a single step, integrated with the CO2 compression process for urea synthesis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydrogen and methanol are removed by oxidation with air or oxygen in a catalytic reactor and water washing in another apparatus, then hydrogen and methanol are removed from the CO2 feed, but the process requires two separate units and big and complex equipment
Solution Approach 1:
The patent combines the oxidation of hydrogen and methanol into a single catalytic reactor by using a bifunctional catalyst that can oxidize both contaminants simultaneously. This merges two previously separate purification steps (hydrogen removal and methanol removal) into one unit, reducing equipment complexity while maintaining effective removal of both contaminants from the CO2 feed
2Reliability
If methanol is removed by water washing in another apparatus, then methanol is removed from the CO2 stream, but large flowrates of water are required
Solution Approach 1:
The patent replaces the mechanical water washing process with a catalytic oxidation process. Instead of using large amounts of water to wash out methanol, a catalyst oxidizes methanol to carbon dioxide and water, eliminating the need for water washing equipment and dramatically reducing water consumption while achieving effective methanol removal
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 simplifies the purification process, reduces water consumption, and achieves high-purity CO2 with low residual hydrogen and methanol levels, enhancing urea synthesis efficiency and safety by integrating the purification with CO2 compression.
Implementation Method 1
a catalyst which oxidizes hydrogen to water and methanol to carbon dioxide
Implementation Method 2
contacting the CO2 stream with a catalyst which oxidizes hydrogen to water and methanol to carbon dioxide
Data Source
AI summary
A process for removing hydrogen and methanol from a CO2 stream which contains hydrogen and methanol as contaminants, wherein hydrogen and methanol are removed by contacting the CO2 stream with a catalyst which oxidizes hydrogen to water and methanol to carbon dioxide, obtaining a purified CO2 stream.