Acid Temperature Control and Heat Recovery

H2SO4 is made by the reaction of 803(g) with H20(f) in strong sulfuric acid, i.e.  

The reaction is exothermic. It releases about 130 MJ of heat per kg-mole of 803(g). 

A result of this is that H28O4 making s output acid is 25 K warmer than its inlet acid. Fig. 24.1 describes the process. 

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A reaction section, where operations are conducted in a reactor fed in descending stream with a mixture of p-xyiene, acetic acid and catalyst solution prepared in a separate device. The reaction medium is agitated by the introduction of air at the bottom. The corrosive action of bromine and organic acids on carbon steels makes it necessary to use special, stainless materials (Hastelloy C), both for the reactor and for certain parts of the equipment, particularly the heat recovery system. The temperature and oxygen content of the reaction medium must be carefully controlled to prevent the formation of undesirable side products. The heat of reaction is removed by vaporization of part of the reaction medium (acetic acid, p-xylene and water), and by condensation and reflux to the reactor. Residence time is about one hour, and the yield is up to 95 molar per cent... 

Sunflower Helianthus annuus) Traditional inbred line HA89 Controlled temperature conditions Control temperature 25°C Heat treatment 35°C and above 24 hours, consecutive days Grain-filling (Rapid TAG accumulation) 19-26 DAA Increased oleic acid percentage of 29% compared to the control (34% oleic acid) reduced ODS activity with no recovery in the post-stress period Rondanini et al. (2003)... 

Monomer and initiator must be soluble in the liquid and the solvent must have the desired chain-transfer characteristics, boiling point (above the temperature necessary to carry out the polymerization and low enough to allow for ready removal if the polymer is recovered by solvent evaporation). The presence of the solvent assists in heat removal and control (as it also does for suspension and emulsion polymerization systems). Polymer yield per reaction volume is lower than for bulk reactions. Also, solvent recovery and removal (from the polymer) is necessary. Many free radical and ionic polymerizations are carried out utilizing solution polymerization including water-soluble polymers prepared in aqueous solution (namely poly(acrylic acid), polyacrylamide, and poly(A-vinylpyrrolidinone). Polystyrene, poly(methyl methacrylate), poly(vinyl chloride), and polybutadiene are prepared from organic solution polymerizations. 

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