Designing heating/cooling system

[Jackwill]

So I need to design the heating and cooling system for a batch plant (pharmaceuticals).

Majority of the unit operations are jacketed vessels (reactors, filters etc.)
How can I heat up and cool down a single operation?
For example, I need to heat up 'reactor 1' to 100 degrees then gradually cool it down to -10 degrees.
I was thinking of using dowfrost as the heat transfer fluid as it has a big temperature range so could do both, but how exactly would the dowfrost be heated up to 100 degrees?

For the cooling process some sort of chiller/fridge could be used.

Are there better options I haven't thought of?

Beginner chemical engineering student so please spare my lack of knowledge.

 

[MatthewL]

Is this a new facility, or is it an expansion of an existing facility? Will you have any utilities (steam, heating fluid systems, cooling/chilled water, etc.) available? Are your units in F or C? Sounds a lot like homework, but here are my 2 cents:

As a first pass at this, I would suggest using a two exchanger system for your heating fluid (and dowfrost would probably be a good bet for the rxr heating/cooling fluid), one used to heat the fluid and the other to cool. You will need control valves to switch between heat exchangers as you go from heating to cooling and an expansion tank to accommodate the changes in liquid volume as you heat/cool the dowfrost. Remember that the dowfrost will need to be significantly above (during heating) and below (during cooling) your desired product temp if you want to achieve your SP in anything like a reasonable time frame, however, make sure that you don't have problems with skin temps that are too high/low that could affect product quality. Low pressure steam would likely be a good heat source for heating the vessel with a shell and tube exchanger or hot water if your 100 degrees is in F. You will need a chiller for cooling, with either a direct loop (refrigerant to dowfrost) or secondary loop (refrigerant to glycol or similar to dowfrost) heat exchanger. This could be a plate and frame (if viscosity of dowfrost isn't too high at -10) or shell and tube heat exchanger.



Matt

Quality, quantity, cost. Pick two.

 

[LittleInch]

Lots and lots of variables here. If you can circulate the fluid you don't need intermediate fluids. How much fluid/mass makes a huge difference as does time required to heat up or cool down.

Jackets trend to be used to keep things hot or cold, not affect contents temperature, there's just not enough surface area.

Matthew L makes some good points which maybe demonstrate why there's rarely an simple solution. That's why designers and process engineers exist....

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