Integrated Pyrolysis Combined Cycle Biomass Power System Concept Definition

Abstract

Advanced power systems based on integrated gasification/combined cycles (IGCC) are often presented as a solution to the present shortcomings of biomass as fuel. Although IGCC has been technically demonstrated at full scale, it has not been adopted for commercial power generation. Part of the reason for this situation is the continuing low price for coal. However, another significant barrier to IGCC is the high level of integration of this technology: the gas output from the gasifier must be perfectly matched to the energy demand of the gas turbine cycle.We are developing an alternative to IGCC for biomass power: the integrated (fast) pyrolysis/ combined cycle (IPCC). In this system solid biomass is converted into liquid rather than gaseous fuel. This liquid fuel, called bio-oil, is a mixture of oxygenated organic compounds and water that serves as fuel for a gas turbine topping cycle. Waste heat from the gas turbine provides thermal energy to the steam turbine bottoming cycle.Advantages of the biomass-fueled IPCC system include: combined cycle efficiency exceeding 37 percent efficiency for a system as small as 7.6 MW e ; absence of high pressure thermal reactors; decoupling of fuel processing and power generation; and opportunities for recovering value-added products from the bio-oil.This report provides a technical overview of the system including pyrolyzer design, fuel clean-up strategies, pyrolysate condenser design, opportunities for recovering pyrolysis byproducts, gas turbine cycle design, and Rankine steam cycle. The report also reviews the potential biomass fuel supply in Iowa, provide and economic analysis, and present a summery of benefits from the proposed system. Integrated Pyrolysis Combined Cycle Biomass Power System IntroductionBiomass would appear to be a logical fuel blend in existing coal-fired power plants. Both coal and biomass are solid fuels requiring more difficult storage, handling, and firing provisions compared to liquid or gaseous fuels. However, biomass has distinct physical and chemical characteristics that complicate the simple substitution of biomass for coal in existing boilers.Advanced power systems based on integrated gasification combined cycles (IGCC) are often presented as a solution to the present shortcomings of biomass as fuel. Although IGCC has been technically demonstrated at full scale, it has not been widely adopted for power generation. Part of the reason for this situation is the continuing low price for coal. However, another significant barrier to IGCC is the high level of integration of this technology: the gas output from the gasifier must be perfectly matched to the energy demand of the gas turbine cycle.This project evaluated an alternative to IGCC for biomass power: integrated (fast) pyrolysis combined cycle (IPCC). In this system, solid biomass is converted into liquid rather than gaseous fuel. This liquid fuel, called pyrolytic oil, is a mixture of oxygenated hydrocarbons and water that serves as fuel for a gas turbine topping cycle. Waste heat f...

Life cycle assessment of transportation fuels from biomass pyrolysis

“…In BFB reactors (Figure 1a), a heated sand bed is fluidized by a gas so that the biomass fed into this bubbling bed pyrolyzes by contact with the hot bed particles. The BioTherm process is based on this technology, with a first pilot plant with a feedstock capacity of 100 t/day installed in 2005 and another one with 200 t/day in 2006 [11,19]. The latter plant produced bio-oil for direct combustion in a turbine, but no continuous operation was achieved [11].…”

An economic analysis of mobile pyrolysis for northern New Mexico forests.

“…This problem was reduced at lower pyrolysis temperatures. Other researchers noted a similar challenge (Sandvig et al, 2003), and suggest that careful design can help reduce or eliminate this problem. The diaphragm pump required a re-build mid-way through the test series, underscoring that there is a limited lifetime for most components.…”

“…This feature makes sense for future design work. Other researchers have also designed multi-staged condensation systems (e.g., Mohan et al, 2006;Sandvig et al, 2003) with system enhancement and product fractionation in mind. Our results suggest the present system provides water fractionation, as most of the water was recovered in Stage 2.…”