Current and Forecast Trends in the Wallboard Market
Challenges of Utilising DSG in the Gypsum Market
One of the raw materials that is now being more commonly utilised in the production of gypsum wallboard is desulphogypsum (DSG). DSG is a synthetic form of gypsum derived from fossil-fuelled sources and is being used as a viable substitute to mined gypsum. Of the many new production facilities being built around the world, most will be utilising DSG as a raw material.However, the industry has faced some challenges in recent years when handling and storing dried DSG within a gypsum plant environment. These problems have mainly concerned with the reliable handling, and in particular, pneumatic conveying of different grades of DSG or mineral within the same system. DSG, when analysed, has a crystalline structure and many fines, which is problematic to aerate and has a common tendency to block traditional conveying pipelines.Over a 30-year history, Clyde Materials Handling, a global provider of pneumatic process improvement solutions, have upgraded and replaced many poor performing
pneumatic conveying systems. The knowledge gathered from these experiences has been successfully applied within the gypsum industry, with several new and retrofit DSG storage and conveying systems supplied over recent years. This brochure will highlight how Clyde Materials Handling technologies and solutions in the gypsum market have overcome the issues of utilising DSG in the wallboard production process. Gypsum is a mineral used prevalently in the manufacture of gypsum wallboard, often referred to as plasterboard or drywall. Gypsum wallboard is used as a material in the construction industry and is being increasingly regarded as an environmentally friendly product due to its thermal insulation, sound insulation and pollutant protection characteristics.The global gypsum wallboard industry set new records in 2005, with production increasing by 5.7 per cent. from 7047 million m2 (Mm2) in 2004 to 7452Mm2. Global production is forecast to continue to grow by similar factors over the next two years, with production set to grow to 7840Mm2 and 8230Mm2 by 2006 and 2007 respectively1.In an effort to sustain the growing global demand for wallboard many of the leading operators have extended and expanded their current production facilities, whilst developing new production plants.By the end of 2008, 18 expansion / greenfield production plants will have been commissioned to help cope with the growing growth of the gypsum wallboard market.
Précis of Pneumatic Conveying
Pneumatic conveying is defined as the transport of materials through enclosed pipelines using a gas as the transport medium. Usually the material is being transported between hoppers or silos for various reasons concerned with centralised storage and distributed use.Positive pressure pneumatic conveying can take the form of lean phase or dense phase conveying. Lean phase conveying has been around since 1866, whilst dense phase conveying is a more recent development, dating from the 1950’s2. • Lean Phase: Lean phase conveying is characterised by all of the material particles being suspended in the airflow (Figure 1). This means having an air velocity typically greater than 15m/s and often as high as 30m/s (although it depends on the material).
Figure 1 1Global Gypsum Magazine, January-February 2006, The Global Gypsum Board Industry, Dr. Joe Harder, One Stone Consulting Group 2Marcus, R.D.; Leung, L.S.; Klinzing, G.E.; Rizk, F.; Pneumatic Conveying of Solids : A theoretical and practical approach, Chapman and Hall, 1990
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