The Bureau of Mines has conducted research on a flue gas desulfurization (fgd) process as part of its goal of minimizing the undesirable environmental impacts associated with sulfur dioxide (so2) bearing waste gases. This fgd process, referred to as the modified citrate process, involves absorption of so2 in a buffered citric acid solution. The absorbed so2 is subsequently stripped from the solution using steam, which regenerates the solution and produces a wet so2 product. This product can be further processed to make sulfuric acid or liquid so2. Economic evaluations showed the process to be expensive when the stripper was operated at or near ambient pressures because of the large amounts of steam required for solution regeneration. Research was directed at reducing stem consumption in the stripper. The effect of stripper pressure on steam consumption was investigated. A process research unit (pru) was operated with the stripper pressurized in the range of 5 to 150 psig. Test results showed that steam consumption decreased with increased stripper pressure. For example, when operating the pru stripper at 150 psig, 4.1 Grams of steam per gram of so2 was required to remove 90 pct of the so2 from a 1.0-Vol-pct- so2 gas. This compares to 7.1 Grams of steam per gram of so2 required for 90-pct so2 recovery at 5 psig.