Engineering photochemical smog through convection towers
- Los Alamos National Lab., NM (United States)
Reverse convection towers have attracted attention as a medium for cleansing modern cities. Evaporation of an aqueous mist injected at the tower opening could generate electrical power by creating descent, and simultaneously scavenge unsightly and unhealthful particulates. The study offered here assesses the influence to tower water droplets on the photochemical component of Los Angeles type smog. The primary radical chain initiator OH is likely removed into aqueous phases well within the residence time of air in the tower, and then reacts away rapidly. Organics do not dissolve, but nighttime hydrolysis of N{sub 2}O{sub 5} depletes the nitrogen oxides. A lack of HOx would slow hydrocarbon oxidation and so also ozone production. Lowering of NOx would also alter ozone production rates, but the direction is uncertain. SO{sub 2} is available in sufficient quantities in some urban areas to react with stable oxidants, and if seawater were the source of the mist, the high pH would lead to fast sulfur oxidation kinetics. With an accommodation coefficient of 10{sup {minus}3}, however, ozone may not enter the aqueous phase efficiently. Even if ozone is destroyed or its production suppressed, photochemical recovery times are on the order of hours, so that tower processing must be centered on a narrow midday time window. The cost of building the number of structures necessary for this brief turnover could be prohibitive. The increase in humidity accompanying mist evaporation could be controlled with condensers, but might otherwise counteract visibility enhancements by recreating aqueous aerosols. Quantification of the divergent forcings convection towers must exert upon the cityscape would call for coupled three dimensional modeling of transport, microphysics, and photochemistry. 112 refs.
- Research Organization:
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 10123074
- Report Number(s):
- LA-12762-MS; ON: DE95007727; TRN: AHC29509%%42
- Resource Relation:
- Other Information: PBD: Feb 1995
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
NATURAL DRAFT COOLING TOWERS
FEASIBILITY STUDIES
SMOG
REMOVAL
GAS TURBINE POWER PLANTS
NATURAL CONVECTION
AIR POLLUTION CONTROL
HYDROXYL RADICALS
SCAVENGING
NITROUS OXIDE
NITROGEN OXIDES
SULFUR DIOXIDE
REMEDIAL ACTION
PHOTOCHEMICAL REACTIONS
ATOMIZATION
PARTICULATES
540120
CHEMICALS MONITORING AND TRANSPORT