Shell-and-Tube Stripper Heating Fluid Distributor

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Solution Overview

Problem

Scaling up high-pressure shell-and-tube strippers for urea manufacture leads to severe tube corrosion and inefficient stripping due to inhomogeneous heating, resulting in reduced stripper lifetime and operational inefficiencies.

Innovation Solution

A shell-and-tube stripper design with a heating fluid distributor featuring a belt-shaped space and a distribution plate with varying perforation sizes and densities, which ensures homogeneous heating fluid distribution, reducing tube corrosion and improving stripping efficiency by maintaining consistent temperature across all tubes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If shell-and-tube strippers are scaled up for large-volume urea manufacture, then productivity increases, but tube corrosion becomes severe and stripping efficiency decreases

Engineering Contradiction:

Improveurea production volumeVSAvoidstripper lifetime

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The heating fluid distributor creates local variations in heating fluid flow distribution by using a distribution plate with multiple openings of different sizes and densities in different regions. This ensures that each local area of the tube bundle receives appropriate heating fluid flow, preventing localized overheating and corrosion while maintaining overall high productivity in scaled-up strippers.

Inventive Principle:

Principle #3Local quality

2Productivity

If shell-and-tube strippers are scaled up, then productivity increases, but heating homogeneity deteriorates leading to inefficient stripping

Engineering Contradiction:

Improveurea production volumeVSAvoidtemperature uniformity

Core Design Contradiction:

ProductivityVSStability of the object's composition

Solution Approach 1:

The distribution plate features regions with different opening densities and sizes to locally adjust heating fluid flow. Areas with higher heat demand receive more heating fluid through denser or larger openings, while areas with lower demand receive less, achieving uniform temperature distribution across the entire tube bundle in large-scale strippers.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention changes the physical parameters of the heating fluid distribution system by varying the size and density of openings in the distribution plate. This parameter variation allows optimization of heating fluid flow distribution to match the thermal requirements of different regions in scaled-up strippers, maintaining temperature uniformity despite increased scale.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If conventional heating fluid distribution is used in scaled-up strippers, then device complexity remains low, but tube corrosion increases severely

Engineering Contradiction:

Improveheating fluid distribution systemVSAvoidtube corrosion

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

Rather than using a complex multi-component distribution system, the invention employs a relatively simple distribution plate with varied opening patterns. This plate provides local quality control of heating fluid distribution through geometric variations in openings, effectively reducing corrosion without significantly increasing device complexity.

Inventive Principle:

Principle #3Local quality

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

The solution extends the useful life of strippers to 20-30 years by reducing corrosion and enhancing stripping efficiency through uniform heating, leading to improved urea production capabilities.

Implementation Method 1

the urea/carbamate mixture is heated by means of a heating medium in the shell-side space, commonly steam

Methodology Applied

Scientific EffectHeat conduction: Conduction (thermal)

Implementation Method 2

The urea/carbamate mixture flows into the tubes in a falling film pattern, while the gases rise in the inner part of the tubes

Methodology Applied

Scientific EffectConvection: Convection

Implementation Method 3

the heating fluid distributor comprising an edge wall and a heating fluid distribution plate which is disposed parallel to the lateral cross sections; the edge wall comprising two or more openings and/or a plurality of perforations

Methodology Applied

Scientific EffectFluid flow:

Implementation Method 4

Under the influence of the heat provided by a heating medium such as steam, the ammonium carbamate in the urea and carbamate mixture decomposes to form gaseous NH3 and CO2

Methodology Applied

Scientific EffectThermal decomposition: Thermolysis

Implementation Method 5

The urea/carbamate mixture flows into the tubes in a falling film pattern

Methodology Applied

Scientific EffectFalling film flow:

Data Source

PatentUS11976027B2High pressure strippers for use in urea plants

Publication Date: 2024.05.07 YARA INTERNATIONAL ASA

AI summary

Shell-and-tube strippers for stripping a urea/carbamate mixture, related systems, methods, and uses. The stripper includes a shell, a plurality of tubes disposed within the shell, and a heating fluid distributor for homogenizing the flow of a heating fluid near a heating fluid inlet. The heating fluid distributor includes an edge wall and a laterally disposed heating fluid distribution plate. Related systems, methods, and uses are also provided.