Open AccessMATHEMATICAL MODELLING OF A TWO-STAGE ANAEROBIC DIGESTION PROCESS WITH HYDROGEN AND METHANE PRODUCTION USING ADM1
Author(s) -
Milen Borisov,
D Denchev,
Ivan Stupia
Publication year - 2020
Language(s) - English
DOI - 10.32006/eeep.2020.1.1829
Subject(s) - biogas , anaerobic digestion , biohydrogen , process engineering , methane , process (computing) , bioreactor , dilution , hydrogen production , stage (stratigraphy) , engineering , environmental science , computer science , hydrogen , chemistry , waste management , thermodynamics , physics , organic chemistry , operating system , paleontology , biology
The aim of this study is to implement a mathematical model to simulate the dynamic behaviour of a two-stage anaerobic digestion process for simultaneous production of hydrogen and methane. The process is carried out in two connected continuously stirred bioreactors. The proposed model is developed by reducing the well known IWA Anaerobic Digester Model No 1 (ADM1). In the present study the original model concept was adapted and applied to replicate a two-stage process. The proposed model involves 13 ODEs for the 1st stage and 7 ODEs for the 2nd stage. The numerical coefficient values in the model are taken from specified literature and adapted to the case of wheat straw AD. Important input-output static characteristics and existence of maxima of the input-output static characteristics concerning the biohydrogen and biomethane production in function of the control variable (dilution rate) are presented. Supposing that both bioreactors are operating nearby these maxima the optimal ratio of the working volumes was obtained. Numerical simulations using a specially elaborated web-based software environment are presented to demonstrate the dynamic behavior of the model solutions.