Question

1. Write the overall design strategies for the following equipments by the derivatization of necessary equations from the general mass and energy balances with appropriate assumptions.

1. Write the overall design strategies for shell and tube heat exchangers by the derivatization of necessary equations from the general mass and energy balances with appropriate assumptions.

b. Adiabatic tubular reactor operated with the reaction mixture in liquid state.

Answer 1

Ans 1 )

Shell and cylinder heat exchanger plan :

Most shell-and-cylinder heat exchangers are either 1, 2, or 4 pass plans on the cylinder side. In a solitary pass heat exchanger, the liquid goes in one finish of each cylinder and out the other.

Shell is the holder for the shell liquid and the cylinder pack places inside the shell . Shell diaeter ought to be chosen in such a manner to give a nearby fit fo the cylinder pack. The clearence between the cylinder group and internal shell divider relies upon the kind of exchanger. Shells are generally created from standard steel pipe with acceptable erosion recompense.

Cylinder OD of 75 % and 1" are regular to structure a smaller warmth exchanger . The most effective condition for heat move is to have the greatest number of cylinders in the shell to expand turbulance . The cylinder thickness ought to be sufficient to withstand the inner weight alongside the satisfactory consumption alllowance .

Shell and cylinder heat exchanger are the most versitile kind of warmth exchangers.

*) They are utilized to process ventures , in ordinary and atomic force stations .

*) They are utilized in numerous alternatie vitality applications .

*) Shell and cylinder heat exchangers give moderately huge proportion of warmth move region to volume .

*) They can be effectively claened.

The quantity of cylinders in exchanger relies upon the liquid stream rates and accessible weight drop . The lower speed limit relates to restricting the fouling and upper speed breaking point to compare to the constraining to pace of disintegration .

Material which we use to make the warmth exchanger , the necessities are that it ought to be ease , light weight , high conductivity and great joining properties regularly to the choice of alluminum . The other choice standards for exchanger material relies upon the destructive of the working liquid .

The 90 deg. format will have the most reduced warmth move coefficient and the least weight drop .

The primary warmth exchanger condition is : Q = U x A x ΔTm =

Number of cylinders Nt is reliant on tube side stream conditions . It is reated to the shell distance across , tube length and cylinder breadth along with suitable weight drop and the all out cylinder side stream rate thus the warmth move coefficient . Ao = πdoNtL

Rating of the exchanger intends to assess the thermo water powered execution of a completely indicated exchanger .

There are 3 rating strategy to ascertain heat move coefficient.

* Kern strategy

* Taborek strategy

* Bell delaware

Ans 2 )

Adiabatic reactor: Vessel that is all around protected to limit heat move and has an. increment or lessening in temperature from the underlying bay conditions due exclusively to the. warms of response. Cluster reactor: Vessel utilized for concoction response that has no feed or profluent streams

In a PFR, some of the time called constant cylindrical reactor (CTR), at least one liquid reagents are siphoned through a funnel or cylinder. The substance response continues as the reagents travel through the PFR. ... A PFR has a higher hypothetical proficiency than a CSTR of a similar volume.

an adiabatic procedure, where no warmth streams into or out of the gas since its holder is very much protected, Q = 0. On the off chance that there is likewise no work done, for example a free extension, there is no change in inward vitality. For a perfect gas, this implies the procedure is likewise isothermal.

The dynamic conduct of an adiabatic rounded plant reactor during the startup is illustrated, along with the effect of a feed‐pump disappointment of one of the reactants. A powerful model of the reactor framework is introduced, and the framework reaction is determined as a component of experimentally‐determined, time‐dependent, controlled factors. The estimations of model boundaries are assessed by utilizing the SimuSolv (1991) PC program. The informational collection gathered during the reactor start‐up is utilized for the boundary estimation system. A fantastic understanding is gotten between the exploratory and the determined framework reaction. Numerous continuously‐operated business reactors require a total change of one of the fundamental reactants at the reactor exit. It is demonstrated that for a modern rounded reactor an a lot higher introductory reactor temperature is required during the startup, contrasted with the reactor bay temperature during ordinary steady‐state activity, to guarantee a total reactant transformation. Considerably more examination is important to decide if this is a for the most part substantial standard.