The Kansas Department of Health and Environment (KDHE) is taking comments until March 24 regarding a proposed air quality construction permit that covers a 22-MW, biomass-fired power project of Abengoa Bioenergy Biomass of Kansas LLC.
Abengoa wants to modify two permits previously issued by the KDHE for a biomass-to-ethanol and a biomass-to-energy production facility located in Stevens County, Kansas, near Hugoton.
In September 2011, the KDHE issued a Prevention of Significant Deterioration (PSD) air quality permit and in January 2013, KDHE subsequently issued a PSD permit for four natural gas fired emergency generator engines. This proposed permit will supersede these two permits and will include several modifications, including: operating two of the natural gas fired generators as non-emergency; increasing the size of the emergency fire pump; addition/changes in process tanks; addition of a thermal oxidizer for the ethanol load-out; addition of miscellaneous material handling activities; addition of reheat burner to the biomass boiler; reconfiguration of the biomass storage pile area and ash handling system and other miscellaneous changes.
The biomass-to-ethanol manufacturing facility, employing an enzymatic hydrolysis alcohol production process, will utilize cellulosic feedstock (biomass) such as wheat straw, milo (sorghum) stubble, corn stover, switchgrass, and opportunity feedstocks that are locally available. The cogeneration plant will consist of one steam turbine electrical generator nominally rated up to a total of 22 MW. Electrical power will be supplied exclusively to Abengoa facility.
A bubbling fluidized bed (BFB) boiler had been proposed in the previous projects. The latest redesign was proposed in April 2011 for a 22-MW stoker boiler. The main changes affecting the biomass boiler system were the size reduction of the cogeneration which allows for the use of one 22 MW boiler; and the change in the fuel composition due to the lower power generation need.
Abengoa has had discussions with both stoker-type boiler vendors and fluidized bed combustion (FBC) boiler vendors and has decided that due to the inherent high alkalinity in its feedstock, the ash content of the fuel, and use of enzymatic hydrolysis residuals consisting of lignin-rich stillage cake and thin stillage syrup as the primary boiler fuel, that the stoker-type boiler poses the lowest overall risk to the success of the project. The technical issue that has driven the decision to select a stoker boiler versus a BFB has been to minimize fouling and slagging, and avoid agglomeration risks inherent to a BFB boiler and the intended fuel blend.