Urea Production Gravity Flow Process

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Solution Overview

Problem

Current urea production processes with combined high-pressure reactor, condenser, and stripper sections in a single vessel are costly and difficult to construct due to the complexity and high elevation of heavy equipment, necessitating the use of energy-consuming pumps and compressors.

Innovation Solution

Implementing a process with gravity flow between reactor sections, stripper, and condenser, allowing for two separate, easily constructible reactor sections at low elevation, eliminating the need for pumps and compressors, and using austenitic-ferritic duplex steel to reduce corrosion concerns.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If reactor, condenser, and stripper sections are combined in a single high-pressure vessel, then urea synthesis can be performed in an integrated system, but the manufacturing cost increases and construction becomes difficult

Engineering Contradiction:
Improveintegration of process sectionsVSAvoidmanufacturing cost and construction difficulty
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The single high-pressure vessel is divided into two separate reactor sections (first reactor section and second reactor section) that can be manufactured and constructed independently. This segmentation reduces the complexity of manufacturing and construction while maintaining the integrated process functionality through gravitational flow connection between the sections.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If a single high-pressure vessel is used for urea synthesis, then process integration is achieved, but the plant height increases significantly

Engineering Contradiction:
Improveprocess integrationVSAvoidplant height
Core Design Contradiction:
Adaptability or versatilityVSLength of stationary object

Solution Approach 1:

The process transitions from a vertical integration model (single tall vessel) to a horizontal distribution model (two separate reactor sections at ground level connected by gravity flow). This dimensional change reduces plant height while maintaining process integration through gravitational flow between sections at different locations.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Device complexity

If heavy equipment is located at high elevation, then process integration is simplified, but structural investment costs increase and safety becomes more difficult

Engineering Contradiction:
Improveprocess integration simplicityVSAvoidstructural investment cost and safety
Core Design Contradiction:
Device complexityVSEase of manufacture

Solution Approach 1:

Both reactor sections are positioned at ground level, creating an equipotential arrangement that eliminates the need for complex structural support systems. This positioning simplifies construction, reduces structural investment costs, and improves safety by minimizing work at high elevations while maintaining process integration through gravitational flow.

Inventive Principle:
Principle #12Equipotentiality

4Ease of operation

If pumps and compressors are used to maintain flow between sections, then process control is improved, but energy consumption increases

Engineering Contradiction:
Improveprocess controlVSAvoidenergy consumption
Core Design Contradiction:
Ease of operationVSUse of energy by moving object

Solution Approach 1:

The system uses gravitational flow to move the synthesis solution from the first reactor section to the second reactor section and from the stripper to the condenser, eliminating the need for energy-consuming pumps and compressors. The process control is maintained through the natural gravity-driven flow and pressure differentials inherent in the gravitational flow system.

Inventive Principle:
Principle #25Self-service

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 investment costs, simplifies maintenance and safety, and eliminates the need for energy-consuming equipment, resulting in a more economical and safer urea production process with reduced operational complexity.

Implementation Method 1

the flow of the first synthesis solution from the first reactor section to the second reactor section... is each gravity flow

Methodology Applied
Scientific EffectGravity flow: Gravitation

Implementation Method 2

the flow of the second synthesis solution from the second reactor section to the stripper... is each gravity flow

Methodology Applied
Scientific EffectGravity flow: Gravitation

Implementation Method 3

the flow of the mixed gas stream from the stripper to the condenser... is each gravity flow

Methodology Applied
Scientific EffectGravity flow: Gravitation

Implementation Method 4

the flow of the condensate from the condenser to the first reactor section are each gravity flow

Methodology Applied
Scientific EffectGravity flow: Gravitation

Implementation Method 5

a condenser in which the gases released in the stripping zone are condensed

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 6

the second synthesis solution is stripped with the use of carbon dioxide as stripping gas

Methodology Applied
Scientific EffectStripping: Desorption

Implementation Method 7

a process for the production of urea from ammonia and carbon dioxide

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Data Source

PatentEP3309144B1Process for the production of urea from ammonia and carbon dioxide
Publication Date: 2022.12.21 STAMICARBON BV
  • EP3309144B1 patent drawingFigure 1
  • EP3309144B1 patent drawingFigure 2

AI summary

Process for the production of urea from ammonia and carbon dioxide in a urea plant containing a high-pressure synthesis section comprising two reactor sections, a stripper and a condenser, and a recovery section, wherein in the first reactor section a first synthesis solution is formed that is fed to the second reactor section; fresh carbon dioxide is fed to the second reactor section and in the second reactor section a second synthesis solution is formed that is fed to the stripper, wherein the second synthesis solution is stripped with the use of carbon dioxide as stripping gas and the mixed gas stream obtained in the stripper is sent to the condenser together with fresh ammonia and a carbamate stream, whereafter the condensate that is formed in the condenser is fed to the first reactor section and the urea stream that is obtained in the stripper is further purified in the recovery section, wherein the flow of the first synthesis solution from the first reactor section to the second reactor section, the flow of the second synthesis solution from the second reactor section to the stripper, the flow of the mixed gas stream from the stripper to the condenser and of the condensate from the condenser to the first reactor section is a gravity flow.