Abstract
Biomass gasification is being regarded as an efficient process for the production of heat and power and even for the conversion of biomass into biofuels. Its main drawback is the non-negligible tar formation within the process. As the producer gas temperature decreases in the downstream equipment, tar will condense leading to the fouling, blocking of engines, filters and turbines or catalyst deactivation. The challenge is to remove/reduce tar in the product stream. An oil-based gas washing process (OLGA), combining a collector with an absorber and a stripper, is one of the most adapted processes for tar removal. In this work, simulations were conducted using Aspen Plus. These simulations helped in assessing the efficiency of the process in reducing the tar content for an initial concentration of 7,098 mg/Nm3. The variation of the tar reduction efficiency was studied as a function of the oil flow rate and temperature to validate the simulated data by the experimental one. Results showed that equal overall tar reduction efficiency, of 98.8 %, was achieved for an oil flow rate of 5,500 kg/h at 333 K. However, certain deviation was faced while comparing the elementary tar content reduction. Excluding the light tar components, mainly benzene and toluene, led to this high removal efficiency. By adding those components to the simulations, the tar removal efficiency was reduced to 57.6 %. This work focuses on a large assessment of existing processes and perspectives, in particular the removal of the lightest tar components.
