Spent acid regeneration

Sulfonated EPDMs are formulated to form a number of rubbery products including adhesives for footwear, garden hoses, and in the formation of calendered sheets. Perfluori-nated ionomers marketed as Nation (DuPont) are used for membrane applications including chemical-processing separations, spent-acid regeneration, electrochemical fuel cells, ion-selective separations, electrodialysis, and in the production of chlorine. It is also employed as a solid -state catalyst in chemical synthesis and processing. lonomers are also used in blends with other polymers. 

Both of these processes direct the SO2 absorbed from the FCCU flue gas to the refinery SRU, where it is converted to elemental sulfur and added to the marketable sulfur that is generated by the SRU from H2S. Alternately, the SO2 can be converted to sulfuric acid in a dedicated sulfuric acid plant, or in combination with an existing refinery spent acid regeneration unit. When the SO2 is directed to the SRU, 1 ton of SO2 captured in the scrubber is converted to 0.5 tons of marketable elemental sulfur and less than 0.1 ton of sodium sulfate waste is generated per ton of SO2 absorbed. In an acid plant, 1 ton of SO2 generates 1.5 tons of 98% sulfuric acid. Steam is also generated from the conversion of SO2 in both the SRU and the acid plant, which moderates somewhat the steam consumption rate of the solvent regenerator for both the LABSORB and CANSOLV systems. 

Worldwide, about 180 million tonnes of sulfuric acid are produced per year. 70% comes from burning elemental sulfur. The remainder comes from S02 in smelter, roaster and spent acid regeneration furnace offgases. 

Fig. 4.5. Dynawave scrubber for removing particulate and soluble impurities from cooled (600 K), partially cleaned furnace offgas (Puricelli et al., 1998 Enviro-chem, 2005). Note the (i) upward sprays in and (ii) the weir atop the downcomer. The sprays clean the gas. The weir continuously overflows water, which wets and cools the downcomer walls. These scrubbers are used for both metallurgical and spent acid regeneration furnace gases. Large scrubber details are downcomer diameter 1 m (Hastelloy G30)...

The acid is delivered to the spent acid regeneration plant by ... 

After the above treatments, spent acid regeneration gas typically contains ... 

Monsanto Enviro-Chem (2005) Spent acid regeneration (SAR). www.enviro-chem.com/plant-tech/3rdtier/spentaci.html... 

Table 6.5. Details of zinc roaster and spent acid regeneration gas dehydration plants.

Metallurgical and spent acid regeneration gases contain C02 from fossil fuel and spent acid impurities. C02 concentrations in 1st catalyst bed feed gas are typically ... 

A spent acid regeneration lsl catalyst bed feed gas contains ... 

Metallurgical and spent acid regeneration plants are not quite so steady, but the steady state assumption is still reasonable. 

Chapter 23 examines the input of moist metallurgical and spent acid regeneration gases into Fig. 23.1 s dehydration tower. It quantifies the amount of H20(g) that enters dehydration tower acid ... 

A dry process where the water is eliminated by condensation and then drying and the gases are processed as in the spent acid regeneration process. 

---