NMP Lean Solvent Split Flow for Extractive Distillation Regeneration

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Solution Overview

Problem

Existing solvent regeneration systems in extractive distillation are limited by insufficient heat transfer, restricting the feed rate of solvent to the regeneration unit.

Innovation Solution

A system that splits a high-temperature lean solvent stream into two portions, where one portion is directed to a heat exchanger for heat transfer and the other portion is retained for use in a regeneration unit, allowing simultaneous operation of both units to enhance heat transfer and increase the solvent feed rate without additional equipment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the solvent stream is directed entirely to the heat exchanger for heat transfer, then heat transfer efficiency is improved, but the regeneration unit receives insufficient heat and cannot process high feed rates

Engineering Contradiction:
Improveheat transfer efficiencyVSAvoidsolvent regeneration capacity
Core Design Contradiction:
Use of energy by moving objectVSProductivity

Solution Approach 1:

The solvent stream is divided into two separate streams: a first portion directed to the heat exchanger for heat transfer, and a second portion directed to the regeneration unit for solvent regeneration. This segmentation allows each unit to receive optimized flow rates - the heat exchanger receives sufficient flow for effective heat transfer, while the regeneration unit receives enough flow to maintain high processing capacity and productivity.

Inventive Principle:
Principle #1Segmentation

2Productivity

If the solvent feed rate to the regeneration unit is increased, then productivity is improved, but insufficient heat transfer limits the ability to handle higher feed rates

Engineering Contradiction:
Improvesolvent regeneration capacityVSAvoidheat transfer availability
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

By segmenting the solvent stream into two separate flows, the system can independently optimize each path. The second portion to the regeneration unit maintains high feed rate for improved productivity, while the first portion to the heat exchanger provides sufficient heat transfer capability, resolving the limitation where heat transfer availability constrained feed rate increases.

Inventive Principle:
Principle #1Segmentation

3Productivity

If additional processing equipment is added to increase regeneration capacity, then productivity is improved, but capital expenditure and device complexity increase

Engineering Contradiction:
Improvesolvent regeneration capacityVSAvoidprocessing equipment
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The system dynamically adjusts the split between the first and second portions of the solvent stream based on operating conditions. This dynamic flow distribution allows the existing equipment to handle variable loads and optimize performance without requiring additional capital expenditure or increased device complexity, while still achieving high productivity.

Inventive Principle:
Principle #15Dynamics

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 configuration significantly enhances heat transfer, enabling a 23% increase in solvent regeneration capacity and feed rate, improving operational efficiency and stability in butadiene processing systems.

Implementation Method 1

transferring heat from the first portion to a solvent feed stream to produce a cooled lean solvent stream and a heated solvent feed stream

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Implementation Method 2

the second portion of the high-temperature lean solvent stream retains its enthalpy for utilization within the regeneration unit

Methodology Applied
Scientific EffectEnthalpy utilization: Heat Exchanger

Data Source

PatentEP4670811A1Systems and methods for regenerating extractive distillation solvent with enhanced enthalpy
Publication Date: 2025.12.31 SABIC GLOBAL TECHNOLOGIES BV
  • EP4670811A1 patent drawingFigure 1
  • EP4670811A1 patent drawingFigure 2
  • EP4670811A1 patent drawingFigure 3

AI summary

Provided here are systems and methods that include facilitate regeneration of solvents for extractive distillation solvent with enhanced enthalpy. Examples include a method that includes receiving a high-temperature lean solvent stream including 1-methylpyrrolidin-2-one (NMP) and at a temperature between 145 °C and 155 °C from a degasser column. The method includes splitting the high-temperature lean solvent stream into a first portion and a second portion, transferring heat from the first portion to a solvent feed stream to produce a cooled lean solvent stream and a heated solvent feed stream, and regenerating the second portion to produce a purified lean solvent stream. The method includes directing the cooled lean solvent stream and the purified lean solvent stream to an extractive distillation zone.