Abstract
It is necessary to systematically evaluate site-wide energy efficiency and chemical production for biomass to transportation liquid (BTL) processes. BTL processes consist of biomass collection, biomass fast pyrolysis, bio-oil gasification, water gas shift, acid gas removal, CO2 capture and storage (CCS), Fischer- Tropsch (FT) synthesis, and syncrude refining. Operating parameters determine the transportation liquid production, the exhaust tail gas, and process energy and power demands. For the tail gas treatment, it could burn in utility systems to generate steam and power and realize whole system power and energy self-sufficiency. The components H2 and CO in the tail gas could be recovered and recycled to the FT synthesis for more oil production either. However, the tail gas recovery scenario pays for the cost of burning extra fuel in utility systems and more CO2 emission to the environment.
In this paper, BTL process and utility systems are investigated and optimized simultaneously based on system simulation and mathematical programming method. The correlation among process key operating parameters, tail gas treating scenarios, product outputs, and utility system performance are addressed firstly based on the simulation, and then a MILP model is formulated to achieve an optimal BTL process design and utility system configuration. Barley straw to transport fuel production as well as utility systems are designed as the example to illustrate the optimization methodology.
