Stefan Czernik

Production of Gasoline and Diesel from Biomass via Fast Pyrolysis, Hydrotreating and Hydrocracking: A Design Case

The purpose of this study is to evaluate a processing pathway for converting biomass into infrastructure-compatible hydrocarbon biofuels. This design case investigates production of fast pyrolysis oil from biomass and the upgrading of that bio-oil as a means for generating infrastructure-ready renewable gasoline and diesel fuels. This study has been conducted using the same methodology and underlying basis assumptions as the previous design cases for ethanol. The overall concept and specific processing steps were selected because significant data on this approach exists in the public literature. The analysis evaluates technology that has been demonstrated at the laboratory scale or is in early stages of commercialization. The fast pyrolysis of biomass is already at an early stage of commercialization, while upgrading bio-oil to transportation fuels has only been demonstrated in the laboratory and at small engineering development scale. Advanced methods of pyrolysis, which are under development, are not evaluated in this study. These may be the subject of subsequent analysis by OBP. The plant is designed to use 2000 dry metric tons/day of hybrid poplar wood chips to produce 76 million gallons/year of gasoline and diesel. The processing steps include: 1.Feed drying and size reduction 2.Fast pyrolysis to a highly oxygenated liquid product 3.Hydrotreating of the fast pyrolysis oil to a stable hydrocarbon oil with less than 2% oxygen 4.Hydrocracking of the heavy portion of the stable hydrocarbon oil 5.Distillation of the hydrotreated and hydrocracked oil into gasoline and diesel fuel blendstocks 6. Hydrogen production to support the hydrotreater reactors. The “as received” feedstock to the pyrolysis plant will be “reactor ready.” This development will likely further decrease the cost of producing the fuel. An important sensitivity is the possibility of co-locating the plant with an existing refinery. In this case, the plant consists only of the first three steps: feed prep, fast pyrolysis, and upgrading. Stabilized, upgraded pyrolysis oil is transferred to the refinery for separation and finishing into motor fuels. The off-gas from the hydrotreaters is also transferred to the refinery, and in return the refinery provides lower-cost hydrogen for the hydrotreaters. This reduces the capital investment. Production costs near

Stability of wood fast pyrolysis oil

2/gal (in 2007 dollars) and petroleum industry infrastructure-ready products make the production and upgrading of pyrolysis oil to hydrocarbon fuels an economically attractive source of renewable fuels. The study also identifies technical areas where additional research can potentially lead to further cost improvements.

A perspective on oxygenated species in the refinery integration of pyrolysis oil

Abstract This study evaluates the effects of storage conditions on physical and chemical properties of biomass fast pyrolysis oils exposed to elevated temperatures over extended periods of time. It was performed on oak pyrolysis oil generated in the NREL vortex reactor. Oil samples were stored at three temperatures: 37, 60 and 90°C in glass vessels. Properties of the oils were measured after hours of storage at 90°C, and after days or weeks at lower temperatures. Chemical changes in the oils were measured using GPC (molecular weight distribution) and FTIR spectroscopy. The oil remained a single phase throughout the studied conditions. Its pH was not affected by storage. The water content, viscosity and molecular weight of the oil increased with the time and temperature of storage. First-order reaction kinetics were successfully used to predict changes in molecular weight of the stored oil. FTIR provided evidence that etherification or esterification are mechanisms for condensation of the oil during storage.

Proposed Specifications for Various Grades of Pyrolysis Oils

Pyrolysis offers a rapid and efficient means to depolymerize lignocellulosic biomass, resulting in gas, liquid, and solid products with varying yields and compositions depending on the process conditions. With respect to manufacture of “drop-in” liquid transportation fuels from biomass, a potential benefit from pyrolysis arises from the production of a liquid or vapor that could possibly be integrated into existing refinery infrastructure, thus offsetting the capital-intensive investment needed for a smaller scale, standalone biofuels production facility. However, pyrolysis typically yields a significant amount of reactive, oxygenated species including organic acids, aldehydes, ketones, and oxygenated aromatics. These oxygenated species present significant challenges that will undoubtedly require pre-processing of a pyrolysis-derived stream before the pyrolysis oil can be integrated into the existing refinery infrastructure. Here we present a perspective of how the overall chemistry of pyrolysis products must be modified to ensure optimal integration in standard petroleum refineries, and we explore the various points of integration in the refinery infrastructure. In addition, we identify several research and development needs that will answer critical questions regarding the technical and economic feasibility of refinery integration of pyrolysis-derived products.

Catalytic pyrolysis of nylon-6 to recover caprolactam

A handicap facing both the producer and the user of fast-pyrolysis oils is the lack of a description of these oils that is adequate for commercial applications. These oils are highly oxygenated and are relatively immiscible with petroleum oils. Under the current IEA Biomass Energy Agreement, the new Pyrolysis Activity (PYRA) has taken on the task of establishing a useful description of a series of pyrolysis oils. This series roughly parallels that of petroleum fuel oils already described, so that with as few changes as possible to the users’ equipment, a bio-oil could be used in place of the equivalent petroleum-derived oil. The specifications for biomass pyrolysis oils differ in the density, heating value, water content, and corrosiveness. These proposed specifications are presented for discussion by the biomass conversion community and feedback to the Pyrolysis Activity.

Production of Hydrogen from Biomass by Pyrolysis/Steam Reforming

Abstract Catalytic pyrolysis has been proposed as a possible process for the recovery of caprolactam from waste nylon-6. Promising process conditions, i.e. catalyst and temperature were identified using a micro-scale reactor/molecular-beam mass-spectrometer system. At 330–360°C, in the presence of α -alumina supported KOH, the reaction proceeded at a high rate and selectivity. Only a few minutes were needed to complete the nylon-6 depolymerization with a caprolactam yield of 85%. These results were confirmed in a bench-scale fluidized bed reactor system.

Catalytic Steam Reforming of Biomass-Derived Fractions from Pyrolysis Processes

We successfully demonstrated that hydrogen could be efficiently produced by catalytic steam reforming of carbohydrate-derived bio-oil fractions in a fluidized bed reactor using a commercial nickel-based catalyst. Greater steam excess than that used for natural gas reforming was necessary to minimize the formation of char and coke (or to gasify these carbonaceous solids) resulting from thermal decomposition of complex carbohydrate-derived compounds.

Catalytic Pyrolysis of Biomass

Biomass conversion via hydrolytic, solvolytic, and pyrolytic processes generates liquid streams that, after separation of marketable products, can be used to produce either syngas or hydrogen, a strategy being considered in this work. Catalytic steam reforming of model oxygen-containing compounds, their mixtures, bio-oil, and its fractions has been studied using Ni-based catalysts. Tests performed on a microreactor interfaced with a molecular beam mass spectrometer showed that, by proper selection of the process variables: temperature, steam-to-carbon ratio, gas hourly space velocity, and contact time, almost total conversion of carbon in the feed to CO and CO2 could be obtained. These tests also provided possible reaction mechanisms where thermal cracking competes with catalytic processes. Bench-scale, fixed bed reactor tests demonstrated high hydrogen yields from model compounds and carbohydrate-derived pyrolysis oil fractions. Reforming bio-oil or its fractions required proper dispersion of the liquid to avoid vapor-phase carbonization of the feed in the inlet to the reactor. A special spraying nozzle injector was designed and successfully tested with an aqueous fraction of bio-oil. The techno-economic assessment showed that the process could be economically viable if the lignin-derived oil fraction was sold for adhesives and only carbohydrate-derived fraction was converted to hydrogen.

Fuel Oil Quality of Biomass Pyrolysis OilsState of the Art for the End Users

Converting lignocellulosic biomass into biofuels compatible with the existing petroleum refinery infrastructure requires removal of oxygen from the carbohydrate and lignin-derived molecules. The necessary deoxygenation can be achieved through the rejection of water and carbon oxides which occurs at 4000-600C in the presence of catalysts. The yield of hydrocarbons could theoretically reach 35% of the biomass feedstock. So far, the highest yields achieved were in the range of 12-18%. The most promising deoxygenation catalysts belong to the group of medium-pore size zeolites such as ZSM-5. This chapter reviews the research in the field and provides numerous references to the original work in the area of catalytic pyrolysis of biomass. It also reports on some recent experimental results obtained at National Renewable Energy Laboratory.