Wednesday, August 9, 2017

Estimating a Desalination Plant Size for a Given Output

I searched the Internet to identify desalination plants located around the world.   (At The International Desalination Association website, 18,426 plants are estimated to have been in existence in 2015 – click here to go to this data.)  I identified 20 plants that I was able to find on Google Maps.  I then measured the areas of each plant (using the Satellite view) and graphed the measured area against each plant’s reported water output in millions of gallons per day.  The following graph shows the results of plotting the measured areas against the reported outputs (mgd = millions of gallons per day):




The graph is based on the data in the following table:

mgd/day
acres
25.7
5.4
27.0
6.9
36.0
10.4
52.0
16.2
91.9
18.8
15.9
21.3
92.5
22.0
36.1
22.2
137.4
25.5
84.5
26.4
75.7
30.4
72.1
31.9
47.0
33.1
66.1
35.3
132.1
43.5
72.3
43.7
165.1
49.2
158.5
50.2
168.0
52.4
264.2
85.3


So, what is the value of doing this?  One value might be using the results to estimate a desalination plant size for a given output.   Doing a regression analysis of the correlation between the measured plant sizes in acres and the reported plant outputs in millions of gallons per day (the data in the table above) gives an R square value of 0.7603, indicating some correlation between the two in a series of measurements.   The equation for the resulting regression line is y = 2.9013x – 0.3923 (the graph above provides the R square value, the regression line, and the line's equation).  Using the equation (and assuming the correlation is sufficient),  a plant size for a 100 mgd output would be about 35 acres and a plant size for an output of 150 mgd would be about 52 acres.

It seems to me that using Google Maps to look at chemical sites (such as desalination plants) by satellite photographs has a lot of potential uses, such as what is described above.  I was hoping to find a tipping point such that at a certain plant size, the output suddenly substantially increases, but was not able to get enough data for larger-size plants.



Tuesday, August 1, 2017

Chemical and Metal Shortage Alert – July 2017

The purpose of this blog is to identify chemical and metal shortages reported on the Internet.  The sources of the information reported here are primarily news releases issued on the Internet.  The issue period of the news releases is July 2017.

Section I below lists those chemicals and metals that were on the previous month’s Chemical and Metal Shortage Alert list and continue to have news releases indicating they are in short supply.  Click here to read the June 2017 Chemical and Metal Shortage Alert list.

Section II lists the new chemicals and metals (not on the June alert).  Also provided is some explanation for the shortage and geographical information.  This blog attempts to list only actual shortage situations – those shortages that are being experienced during the period covered by the news releases.  Chemicals and metals identified in news releases as only being in danger of being in short supply status are not listed.

Section I. 

Cobalt:  global; mining not keeping up with demand
Rebar steel: China; production not keeping up with demand
Sand/gravel/cement:  India; supply not keeping up with demand
      
Section II.   Shortages Reported in July not found on the Previous Month’s List

Bauxite:  China; mining not keeping up with demand
Ferrovanadium:  global; supply not keeping up with demand
Framing lumber:  United States; supply not keeping up with demand
Graphite electrodes:  global; supply not keeping up with demand
Polyethylene:  Russia; production not keeping up with demand
Zinc:  global; supply not keeping up with demand

Reasons for Section II shortages can be broadly categorized as: 

1.  Mining not keeping up with demand: bauxite
2.  Production not keeping up with demand:  polyethylene
3.  Government regulations: none
4.  Sources no longer available: none
5.  Insufficient imports: none
6.  Supply not keeping up with demand:  ferrovanadium; framing lumber; graphite electrodes; zinc