New Process Technologies for Renewable Feedstocks
Johnson Matthey’s Davy Process Technology business has developed a new sustainable process for the production of propylene glycol from glycerine, a by-product of biodiesel manufacture.
The increasing emphasis on sustainable technologies, and in particular the use of renewable feedstocks, is opening up a number of possibilities for downstream processing to petrochemicals. Johnson Matthey’s Davy Process Technology (DPT) business has built a portfolio of processes around this area, including the production of natural detergent alcohols from palm kernel oil and ethyl acetate from bioethanol. And now DPT has developed a novel sustainable process for the production of propylene glycol from glycerine, a by-product of biodiesel manufacture.
Biodiesel is an attractive alternative to conventional diesel fuel and its manufacture typically produces about 60% less net-lifecycle carbon dioxide emissions. Despite this, every one tonne of biodiesel produces 100kg (or 10%) of glycerine as a by-product and at present surplus glycerine is disposed of by incineration.
But with increasing interest in bio-diesel use, the potential annual glycerine surplus is likely to reach around 1.2 million tonnes worldwide by 2010. This will result in lower glycerine prices and an increase in the use of glycerine as a product in its own right. Longer term, it will open up many possibilities for processing glycerine to produce value-added petrochemical products which would help make the manufacture of biodiesel more economically viable and benefit the biofuel supply chain.
Apart from animal feed applications and the proposed production of epichlorohydrin from glycerine on a commercial scale, one of the major potential outlets for the large oversupply of glycerine is in the production of propylene glycol. This is where Davy Process Technology has focused its attention.
The main uses of propylene glycol are in unsaturated polyester resins, functional fluids such as de-icers and coolants and personal care products. Commercial propylene glycol production is conventionally based on propylene via the conversion of propylene oxide, so it is sensitive to the price of petroleum. Decoupling propylene glycol manufacture from petroleum would be attractive and exploiting the predicted surplus of glycerine would be one way of achieving this.
Following intensive research, development and testing, DPT has developed a new process for converting glycerine to propylene glycol. A basic engineering package has been completed for a plant to produce over 65,000 metric tonnes of propylene glycol a year and discussions are in progress with potential licensees around the world.
The process adds a new technology offering to DPT’s portfolio, meets the criteria for sustainable processes and avoids the use of non renewable hydrocarbon resources.
Find out more about Davy Process Technologies at www.davyprotech.com.
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