Briquetting of UBC by a double roll press: Part II: Improvement of the Johanson model

Abstract The development of the double roll briquetting technology for UBC (Upgraded Brown Coal) powder is introduced. The previous report noted that the application of the Johanson model to UBC briquetting has some limitations. A solution is provided in this report. The discrepancy between the Johanson model and the actual phenomena is derived from the difference between a flat roll and a pocket roll. A step function conversion from the pressure distribution calculated by the Johanson model offers a simple and effective solution. Using this method, it was proved that the linear relationship between the relative strength and the pressure was maintained during scaling up, but the proportional coefficient between the two decreased in accordance with the briquette size. This phenomenon is explained from the viewpoint of rupture theory.