Abstract: A board composed of a lignocellulosic material and the modification thereof as the substantial components and having good mechanical strength, even when the board does not contain any components derived from an additive, by utilizing the autoadhesion of a specified lignocellulosic substance. This board is produced by molding under heat and pressure a lignocellulosic substance containing at least 30 weight % of a malvaceae bast plant, being substantially free from any component derived from an adhesive, and has a strength value of more than 100 as defined by the following formula (I): 0.48.times.Y/X.sup.2, wherein Y is a bending strength (kgf/cm.sup.2) and X is a density (g/cm.sup.3). A particulaly preferable example of the plant is the kenaf.

Abstract: A pulverized coal combustion burner includes a pulverized coal nozzle, and secondary and tertiary air nozzles provided in concentric relation to the pulverized coal nozzle. A flame stabilizing ring is provided at an outlet end of the pulverized coal nozzle. A separation wall is provided within the pulverized coal nozzle to divide a passage in this nozzle into two passages. A pulverized coal/air mixture flows straight through the two passages, so that recirculation flows of the pulverized coal/air mixture are formed in proximity to the outlet end of the pulverized coal nozzle. As a result, the ignitability of the pulverized coal, as well as a combustion rate, is enhanced, thereby reducing the amount of discharge of NOx.