Should Biomass Be Used for Power Generation or Hydrogen Production?

In the last years gasification has become an interesting option for biomass utilization, since the produced gas can be used as a gaseous fuel in different applications or burnt in a gas turbine for power generation with a high thermodynamic efficiency. In this paper a techno-economic analysis was carried out in order to evaluate performance and cost of biomass gasification systems integrated with two different types of plant, respectively for hydrogen production and for power generation. An indirectly heated fluidized bed gasifier has been chosen for gas generation in both cases and experimental data have been used to simulate the behavior of the gasifier. The hydrogen plant is characterized by the installation of a steam methane reformer and a shift reactor after the gas production and clean-up section; hydrogen is then purified in a pressure swing adsorption system. All these components have been modeled following typical operating conditions found in hydrogen plants. Simulations have been performed to optimize thermal interactions between the biomass gasification section and the gas processing. The power plant consists of a gas-steam combined cycle, with a three pressure levels bottoming cycle. A sensitivity analysis allowed to evaluate the economic convenience of the two plants as a function of the costs of the hydrogen and electrical energy.