Flameless Oxy-Combustion CO2 Production for Urea Plants
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Solution Overview
Problem
Existing urea production processes face limitations in CO2 availability, leading to increased energy consumption and high costs, especially when using ammonia plants based on reforming or gasification, and are inflexible with varying fuel supplies, as they require additional ammonia synthesis and separation sections and are not suitable for managing different carbon supply compositions.
Innovation Solution
Integration of a flameless oxy-combustion unit within the urea production plant to produce CO2 through a pressurized flameless oxy-combustion process, allowing for efficient CO2 capture and utilization, reducing energy consumption, and enabling the use of diverse carbon supplies, including waste materials, while minimizing exhaust treatment and air purification needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If CO2 is recovered from ammonia plant process gas, then CO2 is available for urea synthesis, but the quantity of CO2 is limited by the ammonia plant capacity and supply composition
Solution Approach 1:
The patent combines the ammonia plant and oxy-combustion CO2 production unit into an integrated system where the oxy-combustion unit specifically produces CO2 for urea synthesis, decoupling CO2 quantity from ammonia plant capacity limitations
Solution Approach 2:
The oxy-combustion unit serves multiple functions: producing CO2 for urea synthesis, generating steam for process heating, and providing a flexible CO2 source that can accommodate varying ammonia plant capacities and fuel compositions
2Quantity of substance
If the ammonia plant's process gas production section is enlarged to increase CO2 production, then CO2 quantity increases, but energy consumption increases correspondingly
Solution Approach 1:
The patent merges CO2 production with steam generation in a single oxy-combustion unit, where the combustion process simultaneously produces both CO2 and thermal energy in the form of steam, eliminating the need for separate energy-intensive CO2 production processes
Solution Approach 2:
The oxy-combustion process changes the combustion parameters by using pure oxygen instead of air, which eliminates nitrogen dilution and allows for more efficient energy utilization while producing concentrated CO2 streams
3Quantity of substance
If CO2 is captured from chimneys through amine washing and regeneration, then CO2 can be recovered, but installation costs and operating costs for solvent regeneration increase
Solution Approach 1:
The patent extracts CO2 directly from the oxy-combustion process stream before it enters the atmosphere, obtaining concentrated CO2 without requiring complex chemical absorption and regeneration systems that would be needed for dilute chimney gas streams
Solution Approach 2:
The oxy-combustion process inherently produces concentrated CO2 streams that require minimal additional processing, making the system self-sufficient for CO2 production without requiring external solvent systems and their associated infrastructure
4Quantity of substance
If ammonia plants based on reforming or gasification are used, then ammonia is produced, but CO2 availability is limited and urea conversion is not possible without external CO2 sources
Solution Approach 1:
The patent combines ammonia production with integrated CO2 production through oxy-combustion of carbon-containing materials, creating a unified system where both reactants for urea synthesis are produced on-site regardless of the ammonia production route used
Solution Approach 2:
The oxy-combustion unit provides universal CO2 production capability that can serve any ammonia production technology (reforming, gasification, or other methods), making the system adaptable to various fuel sources and ammonia plant configurations
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 efficiency and flexibility of urea production by simplifying CO2 capture, reducing energy costs, and allowing the use of variable carbon supplies, increasing plant capacity, and enabling the association of urea and ammonia plants regardless of ammonia production technologies, with reduced exhaust treatment and air requirements.
Implementation Method 1
oxy-combustion is a kind of combustion in which a fuel is burnt using oxygen as a primary oxidant instead of air
Implementation Method 2
combustion of a fuel in the presence of oxygen coming from an air separation unit takes place
Implementation Method 3
by cooling the discharged gases to condense the water, CO2 is recovered with relative minimal energy consumption
Data Source
AI summary
A urea production process comprises a step of synthesis of urea by reaction of ammonia and carbon dioxide, where at least part of the carbon dioxide for the urea reaction synthesis is produced in an oxy-combustion process; the oxy-combustion process is specifically a flameless oxy-combustion process.