Air Liquide Engineering & Construction



Extending Oleochemistry - Bio Propylene Glycol from Glycerin

Bio propylene glycol (Bio PG), a high-quality and versatile product, provides a new outlet for glycerin, and offers cost and environmental advantages to oleochemical producers. Its production is commercially proven, safe, and highly reliable with a ‘green bonus’ over traditional propylene glycol (PG).

Developing oleochemistry

Our quest for extending oleochemistry never stops. Air Liquide Engineering & Construction, the engineering and construction business of the Air Liquide Group, leads the market through its portfolio including Lurgi technologies, with decades of development in oleochemicals.

In the production of bio propylene glycol (Bio PG), we have successfully combined our expertise with commercially-proven licensed BASF technology to develop and bring to market an alternative to conventional propylene glycol (PG – or 1, 2-Propanediol).

Why Bio Propylene Glycol?

Over-supply of glycerin, a byproduct of biodiesel and fatty acid processes, has resulted in a glut in the market and limited outlets for its use. Falling prices have rendered it a low-price, commodity product. Bio PG, a new outlet for glycerin, is a bulk chemical in a fast growing market and offers multiple benefits to producers. Market sources indicate demand of 2.2 million tonnes per annum in 2014 and a growth rate of 4.5% until 2020.


Bio PG, like petro-based PG, has applications in many different industries. It is a feedstock for polyester resins and urethanes, is used in functional fluids such as aircraft de-icing and in automotive anti-freeze, and acts as a preservative in food and beverage processing, and a solvent and active ingredient in pharmaceutical and cosmetics applications.

…a five-fold increase in product value

PG provides a high value-added downstream product for abundant low-cost glycerin. In the course of last year, the average price for one tonne of glycerin was $200-250/tonne while the price of PG was $1,100-1,500 per tonne.

…a highly competitive drop-in for conventional propylene glycol market

Bio PG retains the product characteristics and qualities of petro-based PG, as an odourless, tasteless, clear liquid that is typically produced to a technical grade of more than 99.5% purity. Pharma grade PG is possible to produce depending on feedstock quality. Making the transition to Bio PG therefore, means users need have no concerns about its impact on their existing customers or applications. It can simply replace existing uses, providing better product quality and characteristics, but at a much more attractive price.

PG Graph

…the production process is safe and potentially more flexible

Bio PG production involves less risk than traditional PG processes. There is no handling of hazardous chemicals, and none of the explosion risk inherent in the use of propylene oxide.

The avoidance of propylene oxide, which is also costly and requires operations of sufficient scale, opens up potential Bio PG production to smaller, more remote biodiesel producers. Existing biodiesel producers can install a Bio PG plant near their existing plant (where they may need to import quantities of glycerin) and the lower average capacity enables smaller operators to participate in the market.

The green chemistry of Bio PG production, involving the catalytic hydrogenolysis of glycerin, uses hydrogen as a feedstock. Here again, Air Liquide Engineering & Construction has extensive experience and can provide solutions for hydrogen supply.

In the Bio PG process, refined glycerin and hydrogen are converted to crude PG in the liquid phase using a BASF catalyst. The reaction takes place under optimum operating conditions of 75 bar and 200 °C, with a very high yield to PG.

In the subsequent distillation unit, some lighter byproducts are removed together with water, formed in the hydrogenolysis reaction. The PG is obtained as distillate, while some heavy ends are withdrawn from the bottom.


…a smaller environmental footprint

BPG production has a smaller environmental footprint than the manufacture of conventional propylene glycol, generating around 60% lower emissions of CO2 and other greenhouse gas emissions per unit of production, and lower amounts of effluent. Traditional PG manufacturing processes, by contrast, require the use of more hazardous chemicals with harmful environmental impacts.

…commercially proven

The technology for Bio PG production is commercially proven. It has been operating at scale successfully in Europe since 2012.

This combination of leading-edge chemistry, and Air Liquide Engineering & Construction’ track record in engineering services, procurement, and construction brings valuable solutions to the oleochemical market.

More about Air Liquide Engineering & Construction

Air Liquide Engineering & Construction, the engineering and construction business of the Air Liquide Group, builds the Group’s production units (mainly air gas separation and hydrogen production units) and also supplies external customers with its portfolio of technologies. Its industrial gas, energy conversion and gas purification solutions enable customers to optimize the use of natural resources. Air Liquide Engineering & Construction covers the entire project life-cycle: license engineering services/proprietary equipment, high-end engineering and design capabilities, as well as project management and execution services. Its exclusive and innovative technologies are making a contribution to the transition of the energy sector. Air Liquide Engineering & Construction is at work connecting people and ideas everywhere to create advanced technologies to solve customer issues and position Air Liquide Group for growth over the long term.