Heat-Integrated Ammonium Sulfate Crystallization Sections

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Solution Overview

Problem

The production of ammonium sulfate crystals is hindered by the formation of visible solid impurities during crystallization, which reduces the quality and yield of the crystals, especially when different sources with varying impurity compositions are combined and crystallized at high temperatures, leading to inefficient heat use and increased energy consumption.

Innovation Solution

A continuous process involving separate heat-integrated crystallization sections for ammonium sulfate solutions with different impurity compositions, where one group operates at a higher temperature than the other, allowing independent processing and purging to reduce impurity content and enhance crystal quality and yield.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If ammonium sulfate solutions with different impurity compositions are combined and crystallized at high temperatures, then crystallization efficiency is improved, but visible solid impurities form and crystal quality deteriorates

Engineering Contradiction:
Improvecrystallization efficiencyVSAvoidcrystal quality
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent divides the crystallization process into separate sections (first crystallization section and second crystallization section) that handle different ammonium sulfate solutions with different impurity compositions independently. Each section operates at optimized temperatures for its specific feed composition, preventing impurity co-precipitation while maintaining high crystallization efficiency.

Inventive Principle:
Principle #1Segmentation

2Loss of energy

If heat integration is implemented across all crystallization sections, then energy consumption is reduced, but impurity distribution becomes uncontrolled and crystal purity decreases

Engineering Contradiction:
Improvesteam consumptionVSAvoidcrystal purity
Core Design Contradiction:
Loss of energyVSManufacturing precision

Solution Approach 1:

The patent applies different operational conditions to different crystallization sections based on their specific requirements. The first crystallization section operates at a first temperature optimized for its impurity profile, while the second section operates at a second temperature optimized for its different impurity profile. This local optimization maintains crystal purity while still allowing heat integration between sections.

Inventive Principle:
Principle #3Local quality

3Productivity

If high temperature crystallization is used to increase production rate, then productivity improves, but visible solid impurities increase and yield decreases

Engineering Contradiction:
Improveproduction rateVSAvoidvisible solid impurities
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the temperature parameter for each crystallization section based on the specific impurity composition of the feed solution. By optimizing the temperature for each section rather than using a single high temperature for all sections, the process maintains high productivity while minimizing impurity formation through precise parameter control.

Inventive Principle:
Principle #35Parameter changes

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 the formation of visible solid impurities, increases the purity and size of ammonium sulfate crystals, and optimizes energy use by allowing efficient heat integration across multiple crystallization sections, resulting in higher-quality crystals and reduced steam consumption.

Implementation Method 1

A continuous process involving separate heat-integrated crystallization sections for ammonium sulfate solutions with different impurity compositions

Methodology Applied
Scientific EffectHeat integration: Heat Exchanger

Implementation Method 2

crystallization by evaporation typically involves heat input to evaporate solvent and concentrate the remaining solution

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 3

Ammonium sulfate crystals may be obtained by subjecting an ammonium sulfate solution to crystallization

Methodology Applied
Scientific EffectCrystallization: Crystallisation

Data Source

PatentEP3013748B1Process and appparatus for producing ammonium sulfate crystals
Publication Date: 2019.05.22 CAP III
  • EP3013748B1 patent drawingFigure 1
  • EP3013748B1 patent drawingFigure 2
  • EP3013748B1 patent drawingFigure 3

AI summary

The present invention provides a continuous process for producing ammonium sulfate crystals, wherein said process comprises: (a) feeding to a first group of crystallization sections, which crystallization sections are heat integrated in series, a first aqueous ammonium sulfate solution that contains one or more impurities; (b) feeding to a second group of crystallization sections, which crystallization sections are heat integrated in series, a second aqueous ammonium sulfate solution that contains one or more impurities; (c) crystallizing ammonium sulfate crystals in each crystallization section respectively from each of said solutions of ammonium sulfate that contain one or more impurities; (d) purging a fraction of the ammonium sulfate solution that contains one or more impurities from each of said crystallization sections; and (e) discharging ammonium sulfate crystals from each crystallization section, characterized in that: (i) both the first group of crystallization sections and the second group of crystallization sections are together heat integrated in one series of crystallization sections; wherein the first group of crystallization sections operates at higher temperature than the second group of crystallization sections; and (ii) the composition of the first aqueous ammonium sulfate solution that contains one or more impurities is different to the composition of the second aqueous ammonium sulfate solution that contains one or more impurities. Further provided is apparatus suitable for producing ammonium sulfate crystal.