Pipe Reactor for UAS Production with Axial Injection

Solution Overview

Problem

Current reactors for producing urea ammonium sulphate (UAS) face challenges in reacting acid and base within a flow of heat and/or acid-sensitive components without decomposing them, particularly due to high urea losses when using sulphuric acid, which limits the advantages of the liquid route over the solid route.

Innovation Solution

A pipe reactor design with a reactor head for axial injection of acid and ammonia, a pre-reactor for pre-neutralization, and a scrubber system to minimize urea decomposition, allowing acid and ammonia to react before contacting urea, while maintaining turbulence to enhance reaction efficiency and reduce temperature exposure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If sulphuric acid is used to react with ammonia in urea solution to produce ammonium sulphate, then the reaction can proceed, but urea decomposition occurs leading to high urea losses

Engineering Contradiction:

Improveammonium sulphate productionVSAvoidurea losses

Core Design Contradiction:

ProductivityVSLoss of substance

Solution Approach 1:

The reactor is divided into two distinct zones: a first reaction zone where sulphuric acid reacts with ammonia to form ammonium bisulphate, and a second reaction zone where the formed ammonium bisulphate reacts with urea to form ammonium sulphate. This segmentation prevents direct contact between sulphuric acid and urea, thereby reducing urea decomposition while maintaining productivity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Ammonium bisulphate serves as an intermediary substance. First, sulphuric acid reacts with ammonia to form ammonium bisulphate in the first zone. Then, this intermediary ammonium bisulphate reacts with urea in the second zone to produce the final ammonium sulphate product. This intermediary approach avoids the harmful direct reaction between sulphuric acid and urea.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Loss of substance

If the reaction is performed in a single zone, then the process is simple, but urea decomposition is high; if performed in multiple zones, then urea decomposition is reduced, but device complexity increases

Engineering Contradiction:

Improveurea decompositionVSAvoidreactor structure

Core Design Contradiction:

Loss of substanceVSDevice complexity

Solution Approach 1:

The reactor is divided into two distinct zones: a first reaction zone where sulphuric acid reacts with ammonia to form ammonium bisulphate, and a second reaction zone where the formed ammonium bisulphate reacts with urea to form ammonium sulphate. This segmentation prevents direct contact between sulphuric acid and urea, thereby reducing urea decomposition while maintaining productivity.

Inventive Principle:

Principle #1Segmentation

3Productivity

If acid and base are injected axially in the reactor head, then reaction efficiency is enhanced, but temperature control becomes more challenging

Engineering Contradiction:

Improvereaction efficiencyVSAvoidtemperature control

Core Design Contradiction:

ProductivityVSTemperature

Solution Approach 1:

The reactor is divided into two distinct zones: a first reaction zone where sulphuric acid reacts with ammonia to form ammonium bisulphate, and a second reaction zone where the formed ammonium bisulphate reacts with urea to form ammonium sulphate. This segmentation prevents direct contact between sulphuric acid and urea, thereby reducing urea decomposition while maintaining productivity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the reactor are designed with different properties: the first zone is optimized for acid-ammonia reaction, while the second zone is optimized for ammonium bisulphate-urea reaction. Each zone has specific flow patterns and residence times tailored to its function, allowing localized optimization of both reaction efficiency and temperature control.

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

This design enables in situ production of UAS with reduced urea decomposition, producing fine crystals and a more homogeneous product, saving energy and utilities, and allowing for increased urea plant capacity through efficient heat management and selective reaction.

Implementation Method 1

reactor head has means for axial injection of acid and means for injection of ammonia... a reaction chamber where acid and ammonia reactions are enhanced before coming into contact with urea

Methodology Applied

Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 2

pre-reactor for pre-neutralizing the acid is arranged upstream of the reactor head

Methodology Applied

Scientific EffectNeutralization reaction: Chemical Bonding

Implementation Method 3

a scrubber system to minimize urea decomposition, allowing acid and ammonia to react before contacting urea

Methodology Applied

Scientific EffectGas separation: Cyclone Separation

Implementation Method 4

maintaining turbulence to enhance reaction efficiency and reduce temperature exposure

Methodology Applied

Scientific EffectTurbulence: Turbulence

Implementation Method 5

efficient heat management and selective reaction... reduced temperature exposure

Methodology Applied

Scientific EffectHeat transfer: Conduction (thermal)

Data Source

PatentUS8524165B2Pipe reactor and plant for manufacturing of especially urea ammonium sulphate

Publication Date: 2013.09.03 YARA INTERNATIONAL ASA

AI summary

A pipe reactor, especially for production of UAS, includes a tubular body and a reactor head, wherein the reactor head has a device for axial injection of acid, a device for injection of ammonia, a device for supply of urea and a reaction chamber, where acid and ammonia can react before coming into contact with urea.