Pipe Reactor Mixing for Urea Ammonium Sulphate Without Crystallization

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Solution Overview

Problem

Urea crystallization inside a pipe reactor during the production of urea ammonium sulphate increases viscosity and pressure, making the process challenging to run continuously.

Innovation Solution

Pre-heating the ammonia stream to at least 100°C before mixing with ammonium bisulphate in a pipe reactor to prevent urea crystallization and reduce viscosity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If urea is added to the pipe reactor under standard operating conditions, then the production of urea ammonium sulphate proceeds, but urea crystallization occurs inside the reactor increasing viscosity and pressure

Engineering Contradiction:
Improvecontinuous production capabilityVSAvoidprocess stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The ammonia stream is pre-heated to at least 100°C before entering the pipe reactor. This preliminary thermal treatment of the ammonia stream prevents urea crystallization during the subsequent mixing and reaction processes, thereby maintaining process stability and enabling continuous operation without interruptions caused by crystallization-induced pressure buildup

Inventive Principle:
Principle #10Preliminary action

2Reliability

If pre-heating ammonia stream to at least 100°C is implemented, then urea crystallization is prevented and process reliability improves, but energy consumption increases

Engineering Contradiction:
Improveprocess stabilityVSAvoidenergy for ammonia pre-heating
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The heating of the ammonia stream is integrated with the existing thermal infrastructure of the plant. The ammonia pre-heating is combined with the thermal processes already present in the system, allowing heat exchange to occur as part of the overall process flow rather than as a separate energy-intensive operation

Inventive Principle:
Principle #5Merging (Combining)

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

Improves the reliability of the production process by maintaining suitable operating conditions and reducing pressure buildup.

Implementation Method 1

pre-heating the stream of ammonia that is mixed with the solution comprising ammonium bisulphate before the stream of ammonia is directed in the pipe reactor

Methodology Applied
Scientific EffectThermal heating: Heating

Implementation Method 2

the urea added to the pipe reactor started to crystallize inside the reactor, which increased the viscosity of the solution comprising urea and ammonium sulphate

Methodology Applied
Scientific EffectTemperature-dependent viscosity reduction:

Data Source

PatentEP4161874B1Method to produce a urea ammonium sulphate-based composition
Publication Date: 2026.03.11 YARA INTERNATIONAL ASA
  • EP4161874B1 patent drawingFigure 1

AI summary

The present disclosure is related to the methods and devices for the manufacture of a urea ammonium sulphate-based composition, in particular in a pipe reactor. In its broadest aspect, the present disclosure is related to a method for producing a urea ammonium sulphate-based composition in a pipe reactor comprising a first and a second mixing zone. The method comprises the steps of: a) directing a liquid stream comprising ammonium bisulphate to the first mixing zone of the pipe reactor; b) directing a first stream of ammonia to the first mixing zone of the pipe reactor for reacting with the liquid stream comprising ammonium bisulphate, provided in step a), to obtain a liquid stream comprising ammonium sulphate; c) directing the liquid stream comprising ammonium sulphate, provided in step b), to the second mixing zone of the pipe reactor; and d) directing a liquid stream of urea to the second mixing zone of the pipe reactor for mixing with the liquid stream comprising ammonium sulphate, provided in step b), to obtain a urea ammonium sulphate-based composition; wherein, in step b), the first stream of ammonia directed to the first mixing zone of the pipe reactor is pre-heated to at least 100 °C.