97/03521 New applications of roller presses in coal-related technologies

Abstract

The roller press was invented around the middle of the 19th century. Its objective was to develop an economic method for the agglomeration of coal fines. The first successfully operating machine was constructed by the Belgian Louiseau and was installed in a US coal briquetting plant in the late 1870s; therefore this type of equipment was later also referred to as {open_quotes}Belgian Press{close_quotes}. Until the middle of this century many manufacturers produced roller presses and a large number of plants was built, particularly in Europe, to produce mostly egg-shaped briquettes from hard coal fines with coal tar pitch or bitumen as a binder. These briquettes were used as fuel for home and industrial heating. After other, cleaner sources of energy, such as gas, oil, and electricity, became affordable, coal briquetting lost its importance. A small number of almost historic plants is still operating but construction of new ones is scarce. Only a few manufacturers of roller presses are still offering such equipment, mostly for other applications. Recently, a renewed interest in roller presses has developed in connection with innovative coal technologies. These include: Briquetting of non-coking coal for the generation of {open_quotes}form-coke{close_quotes}; production of smoke-less coal briquettes; briquetting of coalmore » for gasification or liquefication techniques; size enlargement by briquetting of fine, upgraded coals, e.g. dried sub-bituminous coal or products from advanced coal cleaning processes, to improve their transport and handling properties; agglomeration of by-products from flue gas desulfurization; and, last but not least, briquetting of coal ashes to allow disposal or beneficial use. In the following such new applications of roller presses for coal related technologies will be reviewed and features of modern machines which are required for their successful operations will be described.« less