Acid temperature control steam production

The capital cost of POX can be high because of the need for post treatment of the raw syngas to remove carbon and acid gases. There are also issues of coke and soot formation if the oxidation temperature becomes too low or the mixing of the feed components is incomplete. The addition of steam to the process allows for greater flame temperature control and suppression of carbon however, the hydrogen production efficiency is reduced due to more fuel being consumed in the combustion... 

Fig. 1. Flow diagram of production of sulfur dioxide from oleum 1, 30% oleum exchanger 2, SO vaporizer 3, reactor 4, coolant surge tank 5, coolant ckculatkig pump 6, coolant exchangers 7, sludge and acid pump 8, scmbber 9, SO2 cooler 10, gas cleaner 11, SO2 compressor 12, pulsation damper and 13, SO2 condenser. CM is the condensate FRC, flow recording controller PIC, pressure kidicatkig controller SM, steam TC, temperature recorder ...

The molecular weight of the polymers is controlled by temperature (for the homopolymer), or by the addition of organic acid anhydrides and acid hahdes (37). Although most of the product is made in the first reactor, the background monomer continues to react in a second reactor which is placed in series with the first. When the reaction is complete, a hindered phenoHc or metal antioxidant is added to improve shelf life and processibiUty. The catalyst is deactivated during steam coagulation, which also removes solvent and unreacted monomer. The cmmbs of water-swoUen product are dried and pressed into bale form. This is the only form in which the mbber is commercially available. The mbber may be converted into a latex form, but this has not found commercial appHcation (38). 

Step 8. Several control valves now remain unassigned. Steam flow to the trim heater controls reactor inlet temperature. Cooling water flow to the trim cooler is used to control the exit process temperature and provide the required condensation in the reactor effluent stream. Liquid recirculation in the absorber is flow-controlled to achieve product recovery, while the cooling water flow to the absorber cooler controls the recirculating liquid temperature. Acetic acid flow to the top of the absorber is flow-controlled to meet recovery specifications on the overhead gas stream. Cooling water flow to the cooler on this acetic acid feed to the absorber is regulated to control the stream temperature. Cooling water flow in the column condenser controls decanter temperature. 

Controlled oxidation of a primary alcohol with a mixture of sulfuric and chromic acids gives the corresponding aldehyde. In the preparation of low-molecular-weight aldehydes, an aqueous medium is used and the product is removed by steam distillation, thus preventing further oxidation. This procedure is well illustrated by the preparation of propion-aldehyde (49%) and isovaleraldehyde (60%). Certain benzyl alcohols are dissolved in aqueous acetic acid for chromic acid oxidation. Ole-finic aldehydes are produced by a rapid low-temperature (5-20°) oxidative procedure, as illustrated by the preparation of 2-heptenal (75%) from 2-heptenol. Aldehyde ethers such as methoxyacetaldehyde and ethoxy-acetaldehyde have been prepared by the chromic acid oxidation of the corresponding alcohols in 17% and 10% yields, respectively. ... 

The polymerization is a comparatively simple process. A 60 per cent solution of the 66 salt in water is pumped into an autoclave. A small amount of acetic acid is added to block some of the amino end groups and thus control the degree of polymerization. The air is then driven out of the autoclave with a stream of steam, because traces of oxygen would cause oxidation and discoloration of the final product. The temperature of the content of the vessel is then raised to 215°C (419°F) at a pressure of 250 lb per sq in. Steam is continuously fed into the heating system for a further 2 to 3 hours, the pressure being maintained at 250 lb per sq in. by allowing the necessary amount of steam to escape from the autoclave. The pressure is then slowly reduced to one atmosphere over a period of between... 

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