Büttner, the energy and drying systems subsidiary of Siempelkamp, will deliver four new drum dryers to the American pellet producer Highland Pellets LLC, AR, Siempelkamp announced.     At the end of June companies signed the supply contract for the new plant, which will be installed in Pine Bluff, Arkansas. Here Highland Pellets has been operating a plant for the production of wood pellets since 2017, which are mainly supplied to the European market.    The total of eight existing dryers - four pre-dryers and four main-dryers - from another supplier did not achieve ...