Methods and apparatus to improve hot gas filtration to reduce the liquid fuel loss caused by prolonged residence time at high temperatures are described. The improvement can be obtained by reducing the residence time at elevated temperature by reducing the temperature of the pyrolysis vapor, by reducing the volume of the pyrolysis vapor at the elevated temperature, by increasing the volumetric flow rate at constant volume of the pyrolysis vapor, or by doing a combination of these.
STATEMENT OF GOVERNMENT INTEREST
 This invention was made under the partial support of the United States Government, United States Department of Energy under Award No. DE-FG36-08GO18213. The United States Government has certain rights in the invention.