Perfis de temperatura em um reator de hidrólise para processamento de biomassas agrícolas usando água a alta pressão

Abstract

In this work, heat transfer calculations and temperature profiles were evaluated in a 316L (50 mL) stainless steel reactor used for hydrolysis of agricultural biomass using high pressure water. The calculations were necessary because the knowledge and control of temperature within the processing bed is the most important factor for high pressure reaction (subcritical hydrolysis). Convection and conduction heat dissipation were considered in the calculations. The variable separation method was used to solve the two-dimensional conduction problem, since the heat transfer occurs in two dimensions because there is a temperature gradient in "x" and in "r" due to the preheated water flow in the reaction bed. For the operational tests of the equipment, temperatures of 180, 220 and 260°C were considered in the subcritical hydrolysis. Through programming and modeling software, internal fluid temperature profiles were obtained from the methods of separation of variables and finite elements, as well as reactor heating profiles, using known boundary conditions. The main results indicated that the inlet temperature and the velocity of the fluid inside the reactor directly influence the temperature profile of the flow, reaching the stationary flow state after 60 mm with a flow rate of 15 mL/min and 85 mm with a flow rate of 30 mL/min.