Once you accept that the investment for a tank or reactor or container scales up with the 1/3rd power of volume then the scale up with pressure naturally follows.

If the rate of reaction of a chemical reaction is proportional to pressure (P) then raising pressure will lower the volume required at the same time that it will raise the thickness of the walls to contain that higher pressure.  It follows that Investment will be:

Investment=k*(1/P)^(1/3)*P

Investment =k*P^(2/3)

If the reaction is proportional to the pressure squared (2 species->one species)

Investment=k*(P)^(1-2/3)=k*(P)^(1/3)

For a 3rd order pressure dependency on the reaction rate the Investment is independent of pressure, i.e.

Investment=k*P^(1-3/3)=k

For orders higher than 3 other things like heat transfer to/from the reactants (i.e. area or order 2),  or limiting conversion to limit temperature rise, or use of diluents to control temperature rise,  may become dominant, limiting the pressure effect between P^0 to P^(1/3).

By my memory the investment for polyethylene plants scale as the 1/4th power of Pressure.

The foregoing is applicable for a fixed production rate.  However if one is in the position of building a plant where the justification of the capital is a key element then one likes to consider investment per annual pound.  Larger plants tend to give lower investments/annual lb.  Since production rate is proportional to P raised to the power of 1,2, or 3 preceding the investment per annual lb will be proportional to Pressure raised to the power of -1/3, -5/6, -6/3=-2.  That being the case plants tend to be at the highest pressure and largest scale.

I was talking to Gregory S. Patince recently about Research being an Investment, or not.  My view of course is that it can be if managed to be an investment.  Just how that is so is included in the following documents.  The criteria of what is required is defined.

research-as-investment-power-point1

research-as-investment-manuscript

These documents are part of the continuing dialog about what Experience Curves are and how they can be extended beyond historic data.

The post titled “Money” shows the GNP or money=k*(employed)^4 and volume=k*(employed)^2.16 and

price=k*(employed)^1.84. In the context of these posts the number of dimensions of the production

facilities, m=2.16 and the price exponent is (4-m). Differenting by parts results is the fraction of the change

in GNP that is real growth is m/4 and the part that is inflation is (4-m)/4. The value of m therefore determines

the fraction that is inflation and real growth. The value of m determine the fraction that is real growth, namely;

m=1 results in 25% real growth,

m=2 results in 50% real growth

m=3 results in 75% real growth.

Obama’s and others “put people to work” with bail-out government money will not help the economy much if

the number of dimensions of  those activities is low (e.g. a shovel in hand ditch digger) vs. high

(like building a petrochemical plant).

Article for Chemtech on the dimensions of economic systems and their business applications (money=k*People^4):

Part One: money22
Part Two: money23

Note Figure 5, a GNP as deflater forecast from 1984 forward that is amazingly accurate.

Article for the Encyclopedia of Chemical Processing and Design:

scale

Explains reason power laws work for scale vs investment rules of thumb.