Pure oxygen production

The following calculation for the vacuum operation is based on the assumptions as (i) negligible pressure drop in fiber lumen (ii) no concentration and temperature gradients in the membrane module (iii) pure oxygen product and (iv) 10% heat loss for the membrane system. Figure 18.9 shows the flow patterns of the membrane system combined with heat exchangers for heat recovery where the parameters for energy calculation are also presented. 

Medium Heat- Value Gas. Medium heat-value (medium Btu) gas (6,7) has a heating value between 9 and 26 MJ/m (250 and 700 Btu/fT). At the lower end of this range, the gas is produced like low heat-value gas, with the notable exception that an air separation plant is added and relatively pure oxygen (qv) is used instead of air to partially oxidize the coal. This eliminates the potential for nitrogen in the product and increases the heating value of the product to 10.6 MJ /m (285 Btu/fT). Medium heat-value gas consists of a mixture of methane, carbon monoxide, hydrogen, and various other gases and is suitable as a fuel for industrial consumers. 

In oxychlorination, ethylene reacts with dry HCl and either air or pure oxygen to produce EDC and water. Various commercial oxychlorination processes differ from one another to some extent because they were developed independentiy by several different vinyl chloride producers (78,83), but in each case the reaction is carried out in the vapor phase in either a fixed- or fluidized-bed reactor containing a modified Deacon catalyst. Unlike the Deacon process for chlorine production, oxychlorination of ethylene occurs readily at temperatures weU below those requited for HCl oxidation. 

Consider the combustion of ethane (C H ) in pure oxygen. If 100 lb of ethane are available and 10% excess oxygen is supplied to ensure complete combustion, calculate (1) the amount of oxygen supplied, and (2) compositions of the reactants and products on mass and molal bases. 

The standard heat of combustion (ziH") of a chemical substance (usually an organic compound) is the same as the standard heat of reaction for complete oxidation of 1 mole of the substance in pure oxygen to yield COj(g) and HjO(f) as products. A reference state of 25°C and 1 atm is assumed in quoting standard heats of combustion in cal/g-mole. The value of AH" is always negative because combustion is an exothermic reaction. Note that the standard heats of combustion for carbon and hydrogen are the same as the heats of formation for CO,(g) and HjO(f), respectively. 

Sulfide ores, after preliminary treatment, most often undergo roasting, that is, heating with air or pure oxygen. With a relatively reactive transition metal such as zinc, the product is the oxide... 

Figure 2.2 shows the cell density and DO level in a pilot-scale aeration vessel. The role of dissolved oxygen in the treatment system is absolutely vital. Therefore the DO level must be maintained at not less than 3-4 ppm in the wastewater for effective aeration. SCP production is veiy oxygen-dependent. The results would be very satisfactory if pure oxygen is used. 

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