Has any body ever thought why we don’t get Beer in PET jar? or PET bottle.
Do you know, whole beer industry is as much intrested in giving beer in PET bottle than us, as this is the cheapest & easy way, though mother nature will not be happy 🙂
Beer in Plastic accounts only for 5-6% in world’s beer package!
What is PET
its short form of Polyethylene Terephthalate, basically a polymer. its extensively used for packaging carbonated drinks.
Whats wrong with PET?
PET absorbs sizable amount of CO2 as the bottle tries to equilibrate with content inside, some study has shwon at 21ºC, PET bottle takes three weeks for 500ppb O2 to invade & four weeks for 10% of the CO2 to wave goodbye.
So what?
OK, Soft Drinks (Carbonated) can tolerate in grease of O2 upto 20ppm, before they change the flavors! so its perfectly on to store it for almost a year!
BUT, for beer, even 0.1 ppm O2 can spoil the itch on tongue! hence normal PET is no-no!
What Next?
People are trying to invent new Coatings to close this barrier or to minimize this sepage! its ‘Work Under Progress’.
Whatever you say, beer look nice in Bottler & Test nice in Glass!
Three cheers to Glass!
Lets Start with Diffrent Loading Calculation
Step : 1
1. Heat Loss to Atmosphere : Surface Area m² X Delta (Tavg – Troom)ºC x 0.32 = Q1 kcal/ hr
2. Cooling Load : Volume of liquid (lits) x Delta (Tstart-Tend)ºC/Time (hr) = Q2 kcal/hr
3. Heat evolved during Chemical process/ Fermentation : Q3 kcal/hr
Total Heat to be Removed = Cooling Load = Q = (Q1 + Q2 + Q3) X factor of safety
Please note Unit of Measurement carefully
for Q3, what process do you follow in your vessel, you need to find out the Load.
Step : 2
Calculate LMTD {Log Mean Temperature}
DT1 = TmediaStart – TcoolenEnd
DT2 = TmediaEnd – TcoolentStart
LMTD = (DT1-DT2)/ ln(DT1-DT2)
Step : 3
Calculate Overall heat Transfer co-efficient & Surface Area Required
Q = U A LMTD
Hence, A = Q / (U x LMTD)
U, Over all heat transfer co-efficient : 100-250 Kcal/ hr ºC m², this is mainly depends uppon what type of jacket do you use, limped coil or limped jacket or profile sheets or laser welded jacket etc. you need to have some co-relation to evaluate this if the construction of jacket is non-standard. for standard type of jacket, you can get more info on following link
http://www.cheresources.com/jacketed_vessel_design.shtml
and if nothing works, ask me 🙂
Step : 4
Calculate amount of Cooling media needed for cooling
Now here is a trick, their are two type of coolent, one, they cool by their latent heat (e.g Ammonia) or two, they cool by dropping their temperature (e.g glycol water)
for First option, we need to consider Enthalpy of latent heat, devide Q by this, and you will get mass flow, for Second type follow following equation
Q = m . cp. DT (Tstartcoolent – TendCoolent)
Make sure you get these enthalpies at the working temperature, refer Perry’s handbook, or ask your cooling supplier for detail physical properties, as these properties changes with pressure & temperature, for water mix coolent like glycol, the properties changes with concentation of media
I hope this is sufficient in-sight, in case of help, let me know
Ok, So you want to design cooling for a vessel.. how to?
Step : 1 : What you should know, and what you should ask
What you should know
a) You should know what type of Vessel Construction your are offering
b) You should know what Jacket for cooling you have
c) You should know your Jacket, Heat transfer co-eff co-releation very well
What you should ask
a) Media to be cooled
b) Media for cooling
c) with agitation or w/o agitation
d) Location (in-house or out-side)
e) Cooling performance needed
Step : 2 : Calculated heat Duty/ Cooling Duty
a) Duty due to Surface Loss
b) Duty due to Fermentation/ Process, i.e to remove heat arising from the process
c) Duty due to Cooling withing given time frame
d) Factor of safety : 10 to 20% depending upon your confidence (prooven history will help to reduce this factor of safety)
Step : 3 : Calculate Amount of cooling media needed
Step : 4 : Calculate Area for Cooling jacket
Step : 5 : Calculate Pressure Drop
Step : 6 : Summary
Next post : How to!
Dear All,
Recently i was working on designing tanks with cooling jacket.
In brewery in particular, there is lots of need of cooling of tank, to take care of heating load generated out of fermentation, surface losses & to get temperature profile.
and as a motive to open this blog, is to share what i learn, in my next post I’ll discuss this in very detail.
See you all soon
PS : if you need any more info ask me, i can add that too in my post!
Welding Process
welding noun /ˈwel.dɪŋ/ n [U] the activity of joining metal parts together
(Definition of welding noun from the Cambridge Advanced Learner’s Dictionary)
Welding in industry has huge spectrum! it starts for arc welding, to fusion welding, to Laser and so on and so forth,
Generally, pressure vessel speaking, we use following three type of welding
– SMAW : Shielded Metal Arc Welding
– SAW : Submerged arc welding
– TIG : Tungsten Inert Gas welding
– GMAW : Gas Metal Arc Welding
Other types are
-Atomic Hydrogen Welding(AHW)
-Bare Metal ArcWelding(BMAW)
-Carbon ArcWelding(CAW)
-Electro Gas Welding(EGW)
-Electro Slag Welding(ESW)
-Plasma Arc Welding(PAW)
-Stud Arc Welding(SW)
Lets discuss Generall Welding Process in Brief
SMAW :
As you can see in picture, the arc is created between Parent material and electrode. The oxidation is avoided by the flux coated on electrode. Due to arc the weld metal start melting, and due to high temperature, the flux also get melted, due to density difference, the flux floats over weld pool, and thus by function makes a barrier between atmosphere & weld to avoid any oxidation.
The temperature found in arc is as high as 7000ºC, at which the gas/air get ionized, providing good electrical conductivity in the arc.
The actual transfer of metal from the electrode to the workpiece is in the form of molten globules of different sizes depending on the type of electrode used. Some electrodes produce globules that are so large that they actually shortcircuit the arc for a moment.
Electrodes for manual arc welding (sometimes referred to as stick welding) consist of a rod and a coating material. As a rule, the alloy in the rod will be similar to the material to be welded.
The most common types of electrodes are:
1. The Organic type (electrodes contain large quantities of organic substances such as cellulose)
2. The Rutile type (electrodes contain large quantities of the mineral rutile)
3. The Acid type (electrodes produce an Iron Oxide / Manganese Oxide / Silica type of slag, the metallurgical character which is an acid.)
4. The Basic type (Low Hydrogen)
5. LMA (Low moisture absorption electrode)
TIG Welding:
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