The Department of Energy is sponsoring a multiphase program to investigate the filtration potential of the moving granular bed filter (GBF) for application in pressurized high temperature energy conversion systems. Phase I, which has been completed, included the development of a mathematical model, a cold flow parametric test series, and investigations of potential dust plugging problems at the inlet screen. During the experimental program, collection efficiencies of 99% and filter outlet loadings less than 0.005 gr/acf were demonstrated. The objectives of Phase II are to investigate the effects of elevated temperature and coal combustion particulate on GBF filtration performance; to continue development of the analytical model to reflect the high temperature effects; to optimize filter internal configuration; to perform parametric and long duration tests to characterize the effects of filter design improvements on filtration efficiencies; and to conduct an economic analysis of full scale filters for PFB service. A secondary objective is to evaluate the effect of combustion additives in reducing the alkali concentration in the outlet from the GBF. Early Phase II hot flow testing confirmed that the original GBF design incorporating inlet and outlet screens exhibited a tendency for extensive and irreversible ash plugging. That led to an alternate design of the GBF internals which eliminated the inlet and outlet screens. This screenless GBF has undergone cold and hot flow tests with collection efficiencies equal to the screened GBF and without ash plugging problems. All current development work under Phase II is being carried out using the screenless configuration. This report updates the work accomplished in the development of the three-dimensional axisymmetrical model, describes two 200-h hot flow tests, analyses of these tests and scaleup efforts initiated during the reporting period.