Olefins & Solvents

Overview

thyssenkrupp Uhde licenses processes for the production of C4 olefins from mixed C4 streams and for the production of solvents by processing propene, C4 olefins, acetone and methanol.

Solvent production

Direct hydration of propene to isopropanol (IPA)

Direct hydration of n-butenes to secondary butanol (SBA) and dehydrogenation of SBA to methyl ethyl ketone (MEK)
Condensation and dehydration of methanol to high-purity dimethyl ether (DME).

C4 olefins

Production of high-purity C4 olefins via extraction from mixed C4 streams in the Uhde BUTENEX® process

Our strengths:

State-of-the-art processes for SBA and IPA production using proprietary acidic ion exchange resin catalysts instead of sulfuric acid
Production of high-purity MEK based on SBA synthesis in a combined SBA/MEK process
The solvent used in the BUTENEX® process exhibits high selectivity, thermal stability and a suitable boiling point
The DME process combines the advantages of a reliable and proven technology with low capital expenditure and low production costs; depending on customer requirements, the DME purity can be varied from fuel grade (above 98%) to high-purity aerosol grade (>99.99%)

Process flow sheets for olefin and solvent production

In the SBA process, SBA is formed by direct hydration of n-butenes with water in the presence of a strongly acidic ion exchange resin catalyst. In a second step, the crude SBA is then distilled to a purity of over 99.0%.

Advantages compared to the sulfuric acid process:

Forms fewer by-products

Lower utilities consumption

Requires no chemicals

Environmentally friendly as it generates no waste.

These advantages cut SBA production costs by around 25%.

The MEK process catalytically dehydrogenates SBA in the presence of a special copper-based catalyst to produce high-purity MEK. The dehydrogenation reaction is endothermic and takes place between 240°C and 270°C. In a second step, hydrogen is recovered as valuable high-purity hydrogen (approx. 99 mol %), and the crude MEK is then dried by means of an entrainer and distilled to a purity of 99.7 wt% on a dry basis.

The IPA process involves the direct catalytic hydration of propene to IPA. In a second step, propylene is recovered and routed back to the reactor section. Finally, IPA is purified in a distillation section. The purity of the technical-grade IPA obtained in this way exceeds 99.9 wt% (dry basis). For the production of 'cosmetic grade' IPA, additional adsorptive deodorisation steps are required.

Advantages compared to the sulfuric acid process:

Lower utilities consumption

Requires no chemicals (such as sulphuric acid and nitric acid), which eliminates corrosion problems and significantly reduces maintenance costs

Environmentally friendly as it generates no waste.

The Uhde BUTENEX^® process is a technology for the separation of pure C4 olefins from various olefinic/paraffinic C4 feedstocks, for example from ethylene crackers or fluid catalytic crackers (FCCs), via extractive distillation (ED) using a selective solvent or a solvent mixture.

The ED process uses a single-compound solvent, N-Formylmorpholine (NFM), or NFM in a mixture with another solvent, typically a morpholine derivative, to alter the vapor pressure of the components to be separated.

The DME process can be used to produce fuel-grade, chemical-grade or aerosol-grade DME.

It involves the catalytic dehydration of methanol in a reactor to form DME and water. The dehydration reaction is exothermic and takes place between 260°C and 310°C. In a second step, DME is separated from the water, non-condensable components and impurities to achieve fuel-grade (over 98%), chemical-grade (99.9%) or even aerosol grade (>99.99%) purities.

Technical publications

The latest publications:

Benefits of C4 hydrocarbon processing (2 parts)

From olefins to oxygenates (direct download)