Simulation Study of Biomass Gasification

As the demand of fossil fuel grows day by day, the sources begin to deplete as well as it’s a non-renewable energy. Thus the need of a competitive renewable energy which can provide as good as fossil fuels keeps growing. In recent times biomass has emerged as a potential long term replacement for energy source instead of fossil fuel. Biomass gasification is one of the potential technologies that can convert biomass into clean and environmental energy. This is because this technology reduces the emission of Carbon Dioxide to the environment and palm kernel is being used as its feedstock due to the fact it produces high amount of hydrogen gas. This research paper is to develop a steady state and dynamic model of biomass gasification system which is located at Block P in University Teknologi PETRONAS. To fulfill this objective, information regarding the operating conditions of the system, and process flow diagram of the system need to be gathered. With using Aspen HYSYS software, a simulation model of biomass gasification is developed in this paper. In this research the temperature and steam to biomass ratio are manipulated to see the effect on gas production in steady state and dynamic mode

Modelling and simulation study of IGCC power plant with activated carbon-based carbon capture process

Integrated Gasification Combined Cycle (IGCC) is considered as a viable option for low emission power generation and carbon-dioxide sequestration. Modelling development and simulation study is essential part for the process of IGCC design and development. This PhD project is aiming to conduct the modelling and simulation study of IGCC power plant by building sub-modules such as gasifier, water gas shift reactor, acid gas removal unit, gas turbine and HRSG, etc. and connecting these modules together for the whole process study. In addition, the impact for the integration of IGCC with activated carbons-based pressure swing adsorption carbon capture process is investigated by using a PSA model developed and validated by University of Birmingham. A simplified zero dimension gasification model is developed based on Texaco gasifier and validated by reference and industry data. The model development is based on mass balance, chemical equilibrium and energy balance. The prediction results for syngas contents concentrations are proved to be reasonably acceptable and the syngas contents changes with key input parameters changes are studied. The model is then used to generate a variable syngas stream to study the dynamic performance of the other sub-modules. A one dimension dynamic model based on Shell slagging gasifier is developed. The model can successfully show the characteristics of slag layers formation and the syngas stream change with response to input parameters change. By using step rise of oxygen input and steam blast input, the dynamic performance of syngas temperature, syngas contents, slag mass flow rate and slag layers thickness is analysed and compared. It is found that oxygen input show relative larger impact on gasifier operation than steam blast for the studied working conditions. Auxiliary modules in a gasification enabled plant and combined cycle power plant are modelled with Thermolib Software. Basic principles of this software are introduced. Simplified quench process, WGS with heat recovery, acid gas removal unit, gas turbine, HRSG and electrical generator are modelled by using the blocks from Thermolib. The simulation results show the dynamic changes of key output variables such as power output, syngas temperature and contents concentrations. PSA model developed by UoB based on ACs is introduced and a 9 step 8 beds cycle model is used for the integration with IGCC model. This PSA model can achieve 80.89% CO2 capture rate with 87.33% of N2 recovery rate without any additional equipment. N2 is used to represent H2 for the simulation. Four cases for IGCC integrated with carbon capture are studied for the energy penalty analysis. It is predicted that the efficiency loss for IGCC power plant with 80.89% carbon capture will be 10.96%. The limitations of using N2 to represent H2 for the PSA model are discussed and it is predicted the real efficiency loss will be lower than the simulation results