Urea Synthesis Additional Reactor Steam Efficiency
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Solution Overview
Problem
Current urea production processes are not energy-efficient and have a low conversion rate, with a desire for more economic operation and increased efficiency in the synthesis process.
Innovation Solution
A process that involves pre-reacting recovered carbamate into urea earlier in the synthesis loop, where the high pressure carbamate condenser is fed with urea and water instead of just ammonia and carbon dioxide, and an additional reactor is used to increase conversion and reduce steam consumption, allowing for a more efficient use of steam and higher urea production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional urea synthesis process is used with ammonia and carbon dioxide in synthesis zone, then urea production is achieved, but energy efficiency is low and steam consumption is high
Solution Approach 1:
The invention applies preliminary action by pre-converting carbamate to urea in an additional reactor before the carbamate enters the synthesis zone. This pre-conversion ensures that carbamate is already transformed into urea before participating in the main synthesis reactions, thereby improving overall energy efficiency and reducing steam consumption in the synthesis zone while maintaining high urea production rates
Solution Approach 2:
The invention changes the parameter composition by introducing pre-formed urea into the synthesis zone along with the recycled carbamate stream. This parameter change modifies the reaction environment to enhance energy utilization efficiency and reduce the steam demand required for the synthesis reactions, thereby resolving the contradiction between energy efficiency and steam consumption
2Productivity
If conventional synthesis process is used, then urea is produced, but conversion rate is low
Solution Approach 1:
The additional reactor performs preliminary conversion of carbamate to urea before the material enters the main synthesis zone. This pre-conversion increases the overall conversion rate by ensuring that carbamate is already transformed into urea before participating in the main synthesis reactions, thereby improving productivity without sacrificing urea production quantity
Solution Approach 2:
The invention implements continuous useful action by recycling the carbamate stream from the recovery section back through the additional reactor and into the synthesis zone. This continuous circulation and re-processing of carbamate ensures maximum conversion rate while maintaining steady urea production, resolving the contradiction between conversion rate and production quantity
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 increases the steam pressure and operating temperature in the carbamate condenser, leading to higher urea conversion rates and reduced steam consumption, making the process more energy-efficient and economically viable.
Implementation Method 1
subjecting the recycled ammonia and carbon dioxide to condensation in a high pressure carbamate condenser
Implementation Method 2
in the first step ammonium carbamate being formed according to the exothermic reaction: 2NH3 + CO2 → H2N - CO - ONH4
Implementation Method 3
the ammonium carbamate formed is dehydrated in the second step to give urea according to the endothermic equilibrium reaction: H2N - CO - ONH4 ↔ H2N - CO - NH2 + H2O
Data Source
AI summary
Disclosed is a urea plant comprising an additional reactor. With reference to the regular components of a urea plant, including a recovery section and a high pressure carbamate condenser, the additional reactor is positioned between the recovery section and the high pressure carbamate condenser. The invention also relates to a process for the synthesis of urea, comprising an additional reaction step converting, at an earlier stage than conventional, recovered carbamate into urea.