Licensed Processes

Ethyl Acetate

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Introduction

This Davy flowsheet is a breakthrough in ethyl acetate (EA) production. We have developed a process that is ideally suited for use with bio-based ethanol feeds and so offers an EA production route that is almost 100% carbon neutral.

Our process is also compatible with petrochemical ethanol feeds where necessary.

Our novel technology has received a number of industry awards, including the Kirkpatrick Chemical Engineering Achievement Award, the Institution of Chemical Engineers Crystal Faraday Award and the Royal Academy of Engineering MacRobert Award.

Process Flowsheet

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Key Reactions

Ethanol dehydrogenation yields ethyl acetate as follows:

Process Description

The key conversion of ethanol to ethyl acetate proceeds in a vapour-phase dehydrogenation reaction, followed by polishing and refining to yield high-purity product.

Process feedstock

The primary feedstock is ethanol, which is obtainable from crop starch fermentation and will usually contain small amounts of water and C4 compounds. Petro-ethanol is also compatible with this process.

Ethanol drying

It is necessary to remove the water from the feed to optimise the downstream dehydrogenation process.

The ethanol/water feed exists as an azeotropic mixture, and drying proceeds in two steps.

Firstly, an azeotrope column takes the feed to the ethanol/water azeotrope which removes the bulk of the water from the ethanol.

The column overheads, composed mainly of ethanol with a small amount of water, then pass through an ethanol mole sieve drying package which further reduces the feed’s water content to required levels.

Dehydrogenation

The dried, superheated ethanol vapour then enters the dehydrogenation reactor.

The vapour stream then flows downwards through several heterogeneous catalyst beds to form ethyl acetate in a two-stage reaction:

In addition, a number of side reactions occur to produce aldehyde and ketone by-products, and these will be removed in the subsequent polishing step.

Finally, a resulting hot process stream comprising ethyl acetate, unreacted ethanol, hydrogen and by-products exits the vessel’s base and passes through several cooling steps to yield a mixture of hydrogen gas and crude liquid product.

This gas/liquid is separated, and the freed hydrogen, following purification and compression, partially returns to the process with the remainder available for export.

The separated crude liquid proceeds to the polishing stage.

Polishing

This step removes the by-products and other possible problem species that cannot be separated from ethyl acetate by distillation.

The crude liquid product stream, and hydrogen gas recycled from dehydrogenation, enter the polishing reactor and flow downwards co-currently over a heterogeneous catalyst.

Here, a hydrogenation reaction converts the aldehyde and ketone by-products to alcohols:

The liquid stream leaving the polishing reactor comprises mainly ethyl acetate product, unreacted ethanol and traces of water and by-products. This stream proceeds to distillation.

Distillation

A patented multi-stage distillation system separates and refines the product ethyl acetate to specification.

Additionally, unreacted ethanol is separated and recycled to the synthesis stage, and trace lights and heavies are removed.

The JM Davy Advantage

Our innovative EA process breaks the dependence upon feedstocks derived from fossil fuels, as it relies only upon ethanol, the majority of which derives from crop starch fermentation.

With crop starch generation being dependent upon atmospheric carbon dioxide, our process does not deplete a non-renewable feedstock.

The advantages flowing from this novel approach include:

+Potential for carbon neutrality:

  • When integrated with a biomass fermentation facility, the Davy ethyl acetate process can be 100% carbon neutral.

+Economic plant construction:

  • Traditional ethyl acetate production routes employ acetic acid as a feedstock, necessitating high-grade stainless steel plant components.
  • By employing a non-acidic feedstock, a Davy ethyl acetate plant can employ lower-grade construction materials, thus reducing investment and maintenance costs.

+Bio-H2:

  • The dehydrogenation reaction produces hydrogen in abundance which can be purified and compressed for export as a valuable feedstock/commodity in its own right.
  • Among other uses, hydrogen serves as the ultimate clean fuel.

+Adds value to ethanol:

  • By employing biomass-derived ethanol as the process feed, we are adding value to a bulk chemical by converting it to a high-value commodity chemical.

+Logistical advantage:

  • Process simplicity and a renewable feedstock achieve greater certainty of production cost and supply.
  • Conventional hydrocarbon-based process routes have several steps, each of which present their own technical, economic and environmental variables – raising uncertainty over production costs and susceptibility to supply failure of feeds and intermediates.
Core Technologies

Learn more about our dehydrogenation technology that transforms ethanol to ethyl acetate:


Core Technologies

Learn more about our dehydrogenation technology that transforms ethanol to ethyl acetate: