The IGT mild gasification process incorporates an integrated fluidized-bed/entrained-bed reactor with heat supplied by a combination of hot char and gas recycle. The use of mild operating conditions (1000 to 1500{degree}F), low pressures (<50 psig), and continuous operation in closed reactors, combined with the potential value-added benefits from the sale of co-products, offer an economical and environmentally sound approach to advanced coal utilization. The tests conducted as Task 4 operated with a full-stream product gas condensate system that was added to the process research unit (PRU). In these tests, the use of recycled char from previous tests mixed with the caking coal feed to the fluidized bed simulated the scale-up process design for the adiabatic process development unit (PDU) using recycled hot char. Also, one test was performed to evaluate the effect of carbon dioxide in the inlet fluidization gas, as would be present in the PDU design using heated recycled product gas for fluidization. Co-product yields and quality were compared with Task 2 data and related to sequential char recycle, fluidization gas, and coal type. Oils/tars yields with Illinois and West Virginia bituminous coals were consistently over 25% by weight of moisture- and ash-free coal, and were not adversely affected either by replacement of coke diluent with mild gasification char or by the use of 19% CO{sub 2} in the fluidization gas. Condensable co-products from the Task 4 PRU tests were evaluated by Reilly Industries for the production of chemicals and pitch binders, and recommendations for liquids upgrading for incorporation into the 24-ton/h PDU design were made. Larger batches of char were generated for preparation of form coke and smokeless fuel briquettes to be tested. 3 refs., 4 figs., 31 tabs.