The US DOE is sponsoring a multiphase program to investigate the filtration potential of the moving bed granular filter (GBF) for application in pressurized high temperature energy conversion systems. The objectives of Phase II of the program 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. Earlier 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 has lead 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 objectives is being carried out using the screenless configuration. The work accomplished in the development of the three-dimensional axisymmetrical model, the hot flow test set-up and the particulate and alkali sampling equipment and procedures, the test plan for hot flow testing, and the results of system checkout following equipment modifications are discussed.