Corona virus

The following is an archive document from the spring of 2020 at the start of the Covid-19 epidemic.

It seems that the Corona virus will spread inexorably.  Once you cut through the panic and BS,  the government plan is to slow the spread so that the health services (and other services) are not completely overwhelmed.

Based on an Excel program I made to chart and predict the possible progress based on the SIR model, a significant proportion of the UK population will have been infected before this is over.

SIR = Susceptible, Infectious, Removed (recovered or died) expressed as fraction of the total population under consideration. The model indicates a peak is likely 2-3 months from now.

Production of oxygen-enriched air on a small scale to satisfy locally the needs of an individual with breathing difficuties is something we should have. The small scale tends to lead you away from the traditional oxygen production methods like cryogenic air separation or PSA or VPSA (Vacuum Pressure Swing Adsorption), and towards semi-permeable membranes.

These have been used on a modest industrial scale to produce pure (99%) nitrogen from compressed air, in which oxygen is the low pressure membrane permeate which is discarded. In this new application we want the permeate, and neither product N2 or O2 needs to be pure.  The duty would be relatively tiny (human demand is ~250 ml/minute as pure O2).

Sizing the membrane is not too difficult. But there are many ways to configure the device –

• a feed air compressor with optional energy recovery from the nitrogen rich retentate (for a human powered device).

• a vacuum pump attached to the permeate side, delivering O2 enriched air at atmospheric pressure.

• Electric mains or rechargeable

Time is of the essence here…