Steam Jacket vs. External Heat Exchanger???

Question

I'm trying to compare the advantages and disadvantages of using a steam jacket on a reactor vs. an external heat exchanger. The steam jacket would be directly heating the reactor and the external heat exchanger would be heating the two inlet streams to this reactor. Please give a few advantages and disadvantages to each.

Answer 1

The steam jacket will give you much less surface area than an external heat exchanger. In addition, the heat transfer coefficient on the steam jacketed vessel will be poor unless you have a very high degree of mixing, and even then, I doubt you can get the velocity at the vessel wall to be in the same range of a properly sized external heat exchanger

The only possible advantage of the steam jacketed vessel is the cost. You will save the cost of the heat exchanger. Since you will already have a pump to transfer the vessel contents, you don't save money there, and if you have an agitator installed, you probably won't save that much.

Answer 2

In addition to cost, steam jackets are used in many cases where you do not want to control the temperature precisely but just want things hot.

Another application for jackets is the situation where the material being heated can plug a conventional heat exchanger's tubes.

Answer 3

Oh, goodness! i'm somewhat rusty at my ChemE and that's totally late right here (between the reliable issues about being a Chem E is that you'll be able to finally have your human being business corporation, although the hours will be difficult each and every from time to time:-), yet, i will do my perfect to placed you on the right highway. also, we used English instruments and they did not ram the Metric gadget down our throats, so that you ought to convert inspite of the actuality that you want to. First, assuming that the steam will enter at 100ºC and go away at 65ºC would purely take position if the steam seize getting used is a sub-cooling form which complicates the calculation because you would possibly want to make sure smart warmth AND latent warmth, yet this example isn't that complicated and also you could assume a wide-spread steam seize which includes a bucket seize. This, of direction, is something they don't educate in Chem E - once you graduate you've little or no authentic-international functional information - maximum ChE's imagine "packing a pump" is putting it in a field! What you probable might want to assume is it enters at 100ºC and the condensate leaves at 100ºC - NO smart warmth benefit. this may be VERY low grade low rigidity steam close to 0 PSIG - probable authentic international will be 30 PSI or better yet in the adventure that they don't inform you, assume dry saturated steam at 100ºC. it isn't substantial, because the enthalpy - latent warmth of vaporization cost of steam, it really is about 900 (at about 60 PSIG) - 970 (at 0 PSIG) Btu/hr does no longer very very much with rigidity. that's critical to, although, if you're given a particular pipe diameter for the steam to enter or go out, because the certain volume of steam does variety lots with temperature/rigidity (save in ideas mostly you take advantage of saturated steam and T & P are tied, as shown by the enthalpy tables). So, assume also that you get condensate leaving at 100ºC for this reason the latent warmth of vaporization of 970 Btu/hr is the large style you want first of all. Google calculator tells me that 12 235 187 (kJ / hr) = 11 596 719.7 btu / hr, so 11,596,720 btu/hr / 970 Btu/lb = 11,955 lbs/hr of dry saturated steam @ 0 PSIG. of direction, the pipe needed to provide this may be huge, it really is why you would use better rigidity steam, although the mass bypass price of the steam might want to no longer be too distinct (of direction, wait till you ought to worry about "average warmth move coefficients" and thermal conductivity coefficients...it really is the position the exciting starts... wish this became of a few help. reliable luck!

Answer 4

hmm i dont know about heat exchangers but can you email me asap? i have some chem questions. thanks!