Vacuum Distillation of Fatty Acid Alkyl Esters with Steam Injection

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Solution Overview

Problem

Current processes for purifying biodiesel from high-sulfur raw materials, such as waste oils and animal fats, often exceed the 10 ppm sulfur limit due to residual sulfur compounds, requiring oversized distillation and additional purification steps, leading to increased costs and reduced efficiency.

Innovation Solution

Introducing water or steam into the distillation column during vacuum distillation, allowing contact with fatty acid alkyl esters in the gas phase to remove volatile components, including sulfur compounds, with optimal water or steam dosage between 0.5-10 kg/t ester, preferably 2.0-5.0 kg/t, to achieve effective sulfur reduction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional washing and distillation are used to purify biodiesel, then the process is simple and easy to operate, but the sulfur content cannot be reduced below 10 ppm

Engineering Contradiction:
Improvesulfur content reductionVSAvoidprocess complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention changes the physical state parameter of water from liquid to vapor phase, and introduces it during the distillation process at specific temperature and pressure conditions. This parameter change enables water to interact with sulfur compounds in the vapor phase, achieving effective sulfur removal while maintaining the simplicity of the distillation process.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

Water vapor acts as an intermediary substance that facilitates the removal of sulfur compounds. The water vapor interacts with sulfur-containing compounds during distillation, enabling their separation and removal from biodiesel without requiring complex additional purification equipment or processes.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If distillation is oversized or operated with less load to handle high sulfur raw materials, then sulfur content can be reduced, but operating costs increase and throughput decreases

Engineering Contradiction:
Improvesulfur content reductionVSAvoidthroughput
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

By changing the operating parameters of distillation - specifically introducing water vapor at controlled amounts (0.5-10 kg per ton of ester) and optimizing temperature and pressure conditions - the process achieves effective sulfur removal at normal distillation capacity, maintaining both high throughput and low sulfur content in the product.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If additional purification steps are added to reduce sulfur content, then sulfur limit can be met, but operational costs and process complexity increase

Engineering Contradiction:
Improvesulfur content reductionVSAvoidoperational costs
Core Design Contradiction:
Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The invention merges the sulfur removal function with the existing distillation process by introducing water vapor during distillation. This combination eliminates the need for separate additional purification steps, reducing operational costs and energy consumption while effectively meeting the sulfur content limit of 10 ppm.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The distillation process is enhanced to perform multiple functions simultaneously: separation of biodiesel components and removal of sulfur compounds. The water vapor introduction enables the distillation column to achieve both purification and desulfurization in a single operation, reducing the need for dedicated additional purification equipment and energy input.

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

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 method significantly reduces sulfur content and neutralization number in biodiesel, meeting regulatory limits without additional purification steps, while maintaining efficient distillation conditions and reducing operational costs.

Implementation Method 1

Method for purifying fatty acid alkyl esters, in particular methyl and ethyl esters, by means of vacuum distillation in a distillation column

Methodology Applied
Scientific EffectVacuum distillation: Vacuum Distillation

Implementation Method 2

the volatile components including water being removed from the fatty acid alkyl esters before the distillation

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 3

water or steam is introduced into the distillation column and contacted with the fatty acid alkyl esters in the gas phase during the distillation

Methodology Applied
Scientific EffectSteam injection:

Data Source

PatentEP3230253B1Method for purifying fatty acid alkyl esters
Publication Date: 2019.12.25 BDI HLDG GMBH
  • EP3230253B1 patent drawingFigure 1~2
  • EP3230253B1 patent drawingFigure 3

AI summary

The invention relates to a method for purifying fatty acid alkyl esters, particularly methyl and ethyl esters, using vacuum distillation in a distillation column, water or steam being introduced into said distillation column and, during distillation, being brought into contact with the fatty acid alkyl esters in the gas phase. This results in a significant reduction in the sulphur content and in the acid value of the fatty acid alkyl ester.