Acid temperature control output

Output acid temperature is controlled by adjusting the H2S04 making tower s ... 

The desired products are hydrocarbons in the C5 to C10 range that can be used in gasoline production. Iron-, cobalt- and nickel-based catalysts plus the proper selection of reaction temperatures and pressures are used to control product output. Increasing residence time in the reactor yields more paraffinic products and reduces the formation of alcohol and acid. 

A first control scheme proposed in [90] is shown in Fig. 10.26. In this scheme, product purities of methyl acetate (MeAC) and water (HjO) are inferred from temperatures on trays 3 and 12, respectively, and the feed rates of methanol (MeOH) and acetic acid (AcH) are used as manipulated variables. For this configuration, three different temperature profiles exist with identical temperature values at the sensor locations but different feed rates and completely different product compositions. The solid line in Fig. 10.26 represents the desired temperature profile with high conversion. This situation corresponds to input multiplicity as introduced at the beginning of section 10.2 on multiplicity and oscillations. Here, the same set of output variables (temperatures) is produced by (three) different sets of input variables (feed rates). Because the steady state values of the output variables are fixed by the given setpoint of the controllers, this input multiplicity will lead to steady state multiplicity of the closed loop system as illustrated in Fig. 10.27. 

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