Catalyst materials to reduce weight, size, and cost of the ozone removal device were developed. Catalyst bed lifetime, competitive reactivity contaminants in the inlet air on the catalyst bed efficiency for ozone removal, and the kinetics and mechanism by which ozone is destroyed on selected catalysts were studied

Wydeven, T.

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Panel on Ozone Destruction Techniques 
Ted Wydeven 
NASA Ames Research Center 
The panel on Ozone Destruction Techniques discussed three 
general areas : 
1. Ozone scrubber design, 
2 .  Adsorbent or catalyst  selection and characterization , 
3. Alternate approaches to  ozone removal. 
In panel discussions on the second day of the Workshop items 1 
and 3 from the l i s t  of three items were eliminated. "Ozone scrubber 
design" was eliminated because i t  was generally thought that  airframe 
manufacturers could do a better job than NASA i n  the engineering of  
scrubbers for a i r c ra f t .  "A1 ternate approaches t o  ozone removal" was 
1 
eliminated f r o m  fur ther  consideration because none of the a1 ternate 
approaches tha t  have e i ther  been t r i ed  or  thought of appeared t o  solve 
the problem of cabin ozone. Alternate approaches were e i the r  to ta l ly  
ineffective or  only par t ia l ly  effect ive.  In some cases a1 ternate 
approaches were also too ineff ic ient  and costly. 
The one area in which the panel f e l t  NASA could make s ignif icant  
contribution was in the development and characterization of new materials 
for ozone removal. The primary objective in developing new materials for  
for  ozone destruction would be t o  reduce weight, s ize  and cost of the ozone 
removal device. The projected weight of the ozone scrubber using currently 
available catalyst  materials i s  150 pounds. No cost o r  s i z e  figures 
were given for  currently available materials. In the development 
of new catalyst  materials, i t  was t h o u g h t  desirable t o  seek catalysts  tha t  
were effective in the two different temperature regimes : 1 ). 200-600'~ 
2 ) .  ambient t o  2 5 0 ~ ~  temperature. Di fferent  a i r c r a f t  woul d require 
catalysts that  ope rab  i n  these di  f fe rent  temperature regions. 
https://ntrs.nasa.gov/search.jsp?R=19790012854 2020-03-21T23:08:57+00:00Z
I n  addi  t i o n  to  d e v e l o p i n g  i mproved rnater i  a l s  f o r  ozone d e s t r u c t  ion 
i t  was g e n e r a l l y  thought  by our panel  members t ha t  NASA could c o n t r i b u t e  
i n  the fo1 lowing areas  : 
1, Study c a t a l y s t  bed l i f e t i m e ,  
2 .  Study c o m p e t i t i v e  r e a c t i v i t y  ( i  .e., t h e  i n f l u e n c e  o f  o t h e r  
contaminants i n  the  i n l e t  a i r  on the  c a t a l y s t  bed e f f i c i e n c y  
f o r  ozone removal, 
3 .  Study t h e  k i n e t i c s  and mechanism by which ozone i s  des t royed  
on s e l e c t e d  c a t a l y s t s .  
The reasons f o r  s t u d y i n g  1 and 2 a r e  obv ious w h i l e  t h e  reasons f o r  
s t u d y i n g  3 a r e  n o t  immed ia te l y  apparent .  The pane1 thought  NASA shou ld  
s t u d y  the k i n e t i c s  and mechanism of ozone d e s t r u c t i o n  f o r  two reasons: 
1 )  w i t h  t h i s  d a t a  ava i  l a b l e  one c o u l d  p r e d i c t  how the  c a t a l y s t  should 
p e r f o r m  under condi t i o n s  n o t  t e s t e d  i n  the  l a b o r a t o r y ,  2) knowing the 
mechanism of ozone d e s t r u c t i o n  on a g i v e n  c a t a l y s t  may a i d  i n  
s p e c i  f y i  ng t h e  r e q u i  remen t s  for  new and improved c a t a l y s t s .  
C a t a l y s t  eva lua t i on  c o n d i t i o n s  would be: 
1 ) .  Contact  or residence time - 5 t o  60 m i l l i s e c o n d s  
2 ) .  I n l e t  ozone c o n c e n t r a t i o n  1.5 ppm 
O u t l e t  ozone c o n c e n t r a t i o n  - 0.1 ppm 
3 ) .  O p e r a t i n g  pressure - 30 - 35 p s i g  (same as 8th stage of 
compressor) .  


Recommendations of the panels: Panel on ozone destruction techniques

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