Senior Design Project

As carbon emissions become a growing cause for global concern, greater pressure has been placed on industry to develop innovative alternatives to traditional commodity chemical production. In order to investigate such an alternative, a design report has been written examining the construction and economic feasibility of a Solar-Thermal Biomass Gasification facility. This facility will serve as an alternative means of high-purity, industrial scale methanol production.

The facility modeled here utilizes 204 million pounds of corn stover biomass per year as feed stock, employs 111 full-time operators, and produces 58,300,000 gal/year of methanol end product. The plant operates in five distinct subunits. Waste corn stover enters the biomass pre-processing portion of the facility where it is ground into usable cellulose and lignin. The usable biomass is then sent to the biomass gasification subsystem, in which a series of three reactors convert the biomass to methanol. In order to mitigate the environmental impact and utility costs of the largest reactor, a solar field operating as part of the facility supplies thermal energy to the solar reactor. An amine scrubbing system purifies the waste gas stream of environmental toxins, while the final stage of product processing entails the purification of the end product methanol, resulting in a final product stream with 99.97% purity by weight. The capital cost of the facility was determined to be $300.5M.

An economic analysis was performed for plant operation in which 12.5% fixed IRR was stipulated for facility investors. This economic analysis returned a 10.8% ROI, 9.2 year PBP and $62.462M NPV based on a 30-year expected facility lifespan with a single year construction period and single year of 50% capacity startup operation. In order to obtain the required 12.5% IRR, the final product selling price was determined to be $1.69/gal methanol. This price is not competitive with the current commodity market value of $1.05/gal (Methanex, 2015). Because of the facility’s inability to ensure investors suitable returns while meeting end-product market value, it is the recommendation of this design team that the Solar-Thermal Biomass Gasification facility not be constructed. In the event that a carbon credit is granted to the facility to incentivize eco-forward industry, a subsidy of $0.21/lb CO2 avoided would be required to reduce the product selling price to market value and render the project economically viable.