Dividing Wall Column for Nitroalkane Recovery

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Solution Overview

Problem

Conventional processes for nitroalkane recovery from nitration of hydrocarbons face challenges due to similar boiling points of byproducts, leading to difficult separation and high energy consumption in distillation, necessitating more economical and energy-efficient methods.

Innovation Solution

A process utilizing a dividing wall column to separate and recover nitroalkanes by reacting hydrocarbon feedstocks with aqueous nitric acid, followed by phase separation and distillation in a dividing wall column to obtain top, middle, and bottom products, thereby reducing capital and energy costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If conventional distillation methods are used to separate nitroalkanes, then separation can be achieved, but energy consumption is high and capital costs are high

Engineering Contradiction:
Improveenergy consumptionVSAvoidseparation difficulty
Core Design Contradiction:
Loss of energyVSManufacturing precision

Solution Approach 1:

The distillation column is divided into two separate columns through a dividing wall, allowing simultaneous separation of different nitroalkane components (e.g., 2-nitropropane and 1-nitropropane) in a single unit. This segmentation enables more efficient separation of components with similar boiling points while reducing overall energy consumption compared to conventional sequential distillation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention introduces a spatial dimension to the distillation process by adding a dividing wall that creates multiple separation zones within a single column. This dimensional change allows for simultaneous separation of multiple components that would otherwise require multiple sequential columns, thereby reducing energy consumption and capital costs.

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

2Manufacturing precision

If conventional distillation methods are used to separate nitroalkanes, then separation can be achieved, but capital costs are high

Engineering Contradiction:
Improveseparation difficultyVSAvoidcapital costs
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

Two distillation columns are merged into a single unit by introducing a dividing wall, creating a dividing wall column that performs the separation functions of both columns simultaneously. This merging reduces capital costs by eliminating the need for two separate columns, foundations, and support structures while maintaining the required separation precision.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The dividing wall column serves multiple separation functions within a single device. It can simultaneously separate different nitroalkane components (e.g., 2-nitropropane from 1-nitropropane) that have similar boiling points, making the device universally applicable to various separation needs without requiring multiple specialized columns.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Manufacturing precision

If additional mass-separating agents are used to recover nitro-paraffin, then recovery can be achieved, but process complexity and costs increase

Engineering Contradiction:
Improverecovery efficiencyVSAvoidprocess complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention extracts and removes the need for additional mass-separating agents by using the dividing wall column's inherent separation capability. The column directly separates nitro-paraffin components based on their volatility differences, eliminating the need for extra extraction steps and agents, thereby simplifying the process while maintaining recovery efficiency.

Inventive Principle:
Principle #2Taking out (Extraction)

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 process achieves efficient recovery of nitroalkanes with reduced energy consumption and capital costs compared to conventional methods, while maintaining high purity and recovery rates of desired products.

Implementation Method 1

distilling the oil phase in a dividing wall column, to recover at least a top product, a middle product, and a bottom product

Methodology Applied
Scientific EffectDistillation: Distillation

Implementation Method 2

separating the product stream into at least an oil phase and an aqueous phase

Methodology Applied
Scientific EffectPhase separation: Liquid-Liquid Extraction

Data Source

PatentEP2490998B1Process for downstream recovery of nitroalkane using dividing wall column
Publication Date: 2018.04.04 ANGUS CHEM CO
  • EP2490998B1 patent drawingFigure 1~2
  • EP2490998B1 patent drawingFigure 3
  • EP2490998B1 patent drawingFigure 4

AI summary

Disclosed are a process and apparatus for synthesizing nitroalkanes by reaction of a hydrocarbon feedstock with aqueous nitric acid. Energy and capital costs may be reduced by using a dividing wall column.