The paper industry is facing the necessity of improving process efficiency, especially in terms of energy and raw materials consumption. In most of the cases, the production of pulp and paper generates an energy surplus that is often not conveniently used. The actual trend is to convert traditional pulp and paper processes in biorefineries where all components of lignocellulosic materials can be converted in added value products such as bioethanol, lignin, cellulose whiskers and other chemicals than can replace the common petroleum based products. In the present work, the energetic and economical efficiencies of two biorefinery processes were studied using the simulation software Aspen Plus. Soda and organosolv processes were used for raw material delignification. The simulation design and treatment sequences (reaction, solid fraction washing, products recovery and liquid fraction processing) are similar for both processes. Mass and energy balances were established and the processes were compared in terms of yield, solvents/reactants recovery and energy consumption based on the same amount of processed raw material. In this way, the development of rigorous simulations allowed to determine the economical feasibility of both biorefinery models, and to establish the optimal operation conditions for both processes.