Another example of a successful Linde solution is the ADALKA® process stabilizer. This process provides a buffering solution, formed by a combination of CO2 and caustic soda (NaOH) to regulate and stabilize pH, alkalinity and calcium levels in the papermaking process. This helps to decrease deposits in the paper machine and thereby extends the maintenance intervals.
CO2 is both more user-friendly and more favourable environmentally than many of the mineral acids it can replace. Its characteristics as a weak acid also have many other benefits in complex chemical systems like the wet end of a paper machine. Captured from exhaust fumes for example in the petrochemical industry, Linde’s CO2 is cleaned and compressed before being re-used. Small but important steps like this can help reduce the overall CO2 footprint.
Wood instead of plastics
Yet one of the most important fields of innovation is biorefinery. In an effort to seek new resources and increase efficiency, the pulp and paper industry is looking at forest biorefinery. “By integrating forest biorefinery activities at an existing plant, pulp and paper mills have the opportunity to produce significant amounts of bioenergy and bioproducts,” writes industry researcher Pratima Bajpai in Biotechnology for Pulp and Paper Processing. Chemicals and pharmaceuticals can be produced from a tree’s bark and other forest residuals; biofuels can be generated from lignin, which is a by-product of pulp production. Making use of such opportunities could “expand the industry’s mission from simply manufacturing low margin products to creating new revenue streams by producing ‘green’ power,” according to Bajpai.
Industry players are putting such technology to good use. The global forestry-products company Stora Enso recently launched a wood-based alternative to oil-derived plastics. The wood fibres, mixed with oil-based polymers and other additives, look a little like popcorn, according to the Economist. Yet they can be melted and moulded like plastic.
Linde supports the move into biorefinery by – among other things – providing gaseous nitrogen to assess the tightness of pipelines or to cool down reactors. “We also provide hydrogen, create inert atmospheres and offer solutions to reduce fire hazard,” says Paolo Kirchpfening, Linde’s marketing manager for Chemicals and Environment. “The pulp and paper industry is ideally positioned to use wood, a re-growing resource, to provide alternatives for oil-based products. Linde is keen to support that.”