Styrene monomer/propylene oxide

Small steps to better chemistry

Styrofoam cups, car bumpers and mattresses haven’t changed much on the outside over the past two decades. But thanks to step-by-step improvements, Shell has made the manufacturing process for the basic chemical building blocks of such products cleaner, more energy efficient and cheaper.

Taken together, the incremental advances since 1980 – when Shell started to commercially produce styrene monomer and propylene oxide – make a significant contribution in a world anxious to conserve resources and protect the environment. Shell’s newest plants use 35% less energy for every tonne of chemicals produced, while air emissions have been cut by 90%.

Learning from experience, Shell researchers gradually introduced small improvements to the production process that were rolled out across factories. At Shell’s plant in the Netherlands, for example, computer analysis of how chemical components mix together inside the vessels where reactions take place led to a design change that both saved energy and increased output.

The analysis found that installing baffles inside reactors broke up air bubbles and promoted better mixing. The improvement allowed ingredients to blend efficiently at lower temperatures, saving energy and cutting costs. The same technology was then introduced at Shell’s Seraya plant in Singapore.

We also developed new wastewater treatment technology that recycles its own heat. Early this decade distillation columns were developed that could separate waste chemicals from the water. Heat released is re-used to warm other distillation columns.

The technology is used in our latest plants. Almost 90% of liquid and solid waste is recycled or re-used for power generation at the Nanhai petrochemicals plant, a 50:50 joint venture with CNOOC in Daya Bay in Guangdong in China. The complex uses 25% less water than other styrene monomer and propylene oxide plants in China.