Process for the removal of acid forming gases from exhaust gases and production of phosphoric acid
- El Cerrito, CA
- San Pablo, CA
Exhaust gases are treated to remove NO or NO.sub.x and SO.sub.2 by contacting the gases with an aqueous emulsion or suspension of yellow phosphorous preferably in a wet scrubber. The addition of yellow phosphorous in the system induces the production of O.sub.3 which subsequently oxidizes NO to NO.sub.2. The resulting NO.sub.2 dissolves readily and can be reduced to form ammonium ions by dissolved SO.sub.2 under appropriate conditions. In a 20 acfm system, yellow phosphorous is oxidized to yield P.sub.2 O.sub.5 which picks up water to form H.sub.3 PO.sub.4 mists and can be collected as a valuable product. The pressure is not critical, and ambient pressures are used. Hot water temperatures are best, but economics suggest about 50.degree. C. The amount of yellow phosphorus used will vary with the composition of the exhaust gas, less than 3% for small concentrations of NO, and 10% or higher for concentrations above say 1000 ppm. Similarly, the pH will vary with the composition being treated, and it is adjusted with a suitable alkali. For mixtures of NO.sub.x and SO.sub.2, alkalis that are used for flue gas desulfurization are preferred. With this process, better than 90% of SO.sub.2 and NO in simulated flue gas can be removed. Stoichiometric ratios (P/NO) ranging between 0.6 and 1.5 were obtained.
- Research Organization:
- Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
- DOE Contract Number:
- AC03-76SF00098
- Assignee:
- Regents of University of California (Alameda, CA)
- Patent Number(s):
- US 5106601
- OSTI ID:
- 868251
- Country of Publication:
- United States
- Language:
- English
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Process for the removal of acid forming gases from exhaust gases
Related Subjects
removal
acid
forming
gases
exhaust
production
phosphoric
treated
remove
contacting
aqueous
emulsion
suspension
yellow
phosphorous
preferably
wet
scrubber
addition
induces
subsequently
oxidizes
resulting
dissolves
readily
reduced
form
ammonium
dissolved
appropriate
conditions
20
acfm
oxidized
yield
picks
water
mists
collected
valuable
product
pressure
critical
ambient
pressures
hot
temperatures
economics
suggest
50
degree
amount
phosphorus
vary
composition
gas
concentrations
10
1000
ppm
similarly
ph
adjusted
suitable
alkali
mixtures
alkalis
flue
desulfurization
preferred
90
simulated
removed
stoichiometric
ratios
ranging
obtained
water temperature
yellow phosphorus
forming gas
gas desulfurization
exhaust gases
phosphoric acid
flue gas
hot water
exhaust gas
ambient pressure
stoichiometric ratio
appropriate conditions
acid forming
acid form
ambient pressures
wet scrubber
forming gases
suitable alkali
aqueous emulsion
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