Calculation method for recovery rate
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I’m seeking help from experts. The problem is as follows: The feed to the tower is 12,500 kg/h, with a mass composition of 0.5843% ethylbenzene, 0.415% styrene, and 0.0007% heptadecane. It is required that the content of these components in the top product of the tower be no less than 99% (by mass), while the styrene content in the bottom product must be no less than 99.7% (by mass). What is the recovery rate of ethylene at the tower top? What is the calculation formula?
This isn’t F=D+W; it’s FXF=DXD+WXW. Well, I’ve learned this before, but I’m almost forgetting it now
Is the top of the tower ethylbenzene? The amount of ethylbenzene in the feed = 12500*0.5843 = 7303.75. The amount of heptadecane in the feed = 12500*0.0007 = 8.75. It is assumed that all of the heptadecane exits at the bottom of the tower. If the amount of product at the top of the tower is x and that at the bottom is y, then 0.99x + (1 – 0.997 – 8.75/y) * y = 7303.75; hence, x = 7370.821. Additionally, 7370.821 * 0.99 / 7303.75 = 0.999091
This post was last edited by ylb913 on 2015-10-28 22:11. Is it ethylbenzene or ethylene at the top of the tower? Let’s assume that the feed containing A has a concentration of 12500*0.5843=7303.75. Assuming that all of the heptadecane ends up in the bottom product, the amount corresponding to it is 12500*0.0007=8.75. Let x represent the amount in the top product and y the amount in the bottom product; then: x+y=12500, and y=12500-x. Substituting these values into the equation 0.99x + (1-0.997-8.75/y)y=7303.75 gives x=7370.821. The concentration of A in the top product is 7370.821*0.99=7297.112. Therefore, the yield of A in the top product is 7297.112/7303.75=99.9091%