Transformation section calculation
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The gas composition entering the shift reactor, as given in the known conditions: Table 1 – Components: CO2, CO, H2, N2, CH4, O2; Total %: 9.6, 1.4, 25.57, 12.25, 6.03, 8.03, 100. Calculation basis: 1 ton of ammonia. The volume of gas required to produce 1 ton of ammonia is calculated as follows: (1000/17) × 22.4/2 × 0.2256 = 2920.31 m3 (standard volume). Since there may be losses during the production process, the volume of gas required is taken as 2962.5 m3 (standard volume). Annual production capacity of 50,000 tons of synthetic ammonia: Daily production amount = 50,000/330 = 151.52 tons/day = 6.31 tons/hour. It is required that the percentage of CO in the dry components of the gas entering the shift reactor be less than 2%. Dry components of the gas entering the shift reactor: Table 2 – Components: CO2, CO, H2, N2, O2, CH4; Total content, %: 9.6, 1.4, 25.57, 12.25, 6.03, 8.03, 100; Volume, m3 (standard): 4745, 63.86, 2750.68, 1113.91, 6.29, 18.76, 34937.5. Question: Are the values in the third column of Table 2, representing the standard volume, correct? For CO, it should be 6.31×2962.5×0.1142=2134 M3/h, right!
In your calculation basis, the volume of the transformed gas is set at 2962.5 cubic meters. I assume what is meant is that the volume of semi-water gas is 2962.5 cubic meters, right? The calculation basis in the third column of Table 2 is even less understandable. The final total of 4937.5 cubic meters doesn’t make any sense. The volume of gas per ton of ammonia should be 2962.5 cubic meters. If it’s the volume per hour, then it would be 2962.5*6.31. Calculating the volume of the transformed gas based on the known carbon monoxide content at the outlet wouldn’t result in such a high value. Since the calculation is based on tons of ammonia, it’s better to use 2962.5 as the value in the third column of Table 2. For carbon monoxide, it would be 2962.5*0.1142 = 338.32 cubic meters.
Such calculations should be done in reverse. 1. Components of the synthetic ammonia feed gas, components of the vent gas, and vent gas recovery rate. 2. Composition of the gas exiting the conversion furnace, further purification – methanation or liquid nitrogen washing. 3. Components of the transformed gas. I wonder if the original poster will be able to figure it out; the method used in the calculation is very crucial.
Thank you! This is a calculation for a student’s graduation project that I saw on this forum; I think there are some issues with it, so I’m seeking advice!
Such calculations have no practical value: the value of 2920.31 (more precisely 2920.317 in terms of calculation accuracy) is derived from equilibrium data assuming no losses in N2; specifically, 1000 (KgNH3) * 22.4/17/2/0.2256 = 2920.317 NM3 of transformed inlet gas. In actual production, the N2 carried away by the vent gas is not taken into account; it can be said that it only has reference value.