• biomass
• downdraft
• gasifier
• modelling
• Python

In this work a dynamic model of a woody biomass down-draft gasifier is developed in Python language which is a high-level programming language available in open-source. The complexity of this system is related to the high interconnection among all chemical reactions and all physical phenomena. The model is able to respond to variation in biomass feed and air feed, in temperature and pressure conditions. It is developed for Enel Green Power Monterotondo plant but, changing geometry parameter, is able to simulate the behaviour of every gasifier of the same type. The model is organized in homogeneous Python libraries that concern specifically aspects like initial conditions, properties or balances. For modelling the gasifier, the biomass bed is outlined in a sequence of continuous stirred tank reactor (CSTR) able to exchange mass and heat with the previous and the successive reactors. The volume of the single reactor is calculated by the algorithm following the geometry of the gasifier. The air inlet is split into reactors that correspond to the gasifier's air inlet zone after flow preheating using produced syngas. Material and thermal balances are solved simultaneously and for every CSTR. The importance of this work is connected to the complexity of the system; the model is useful as support during the plant design, as a test for discovering consequences of a change in operative conditions without real plant’s parameters and as training for plant operators.