The Greenhouse EffectThe Greenhouse Effect

CE 326 Principles of Environmental Engineering CE 326 Principles of Environmental Engineering

Prof. Tim EllisProf. Tim Ellis

January 25, 2010January 25, 2010

Greenhouse EffectGreenhouse Effect

Greenhouse effectGreenhouse effect: n_______ effect : n_______ effect of the gases in earth’s atmosphere to of the gases in earth’s atmosphere to trap incident solar radiationtrap incident solar radiation

earth is an average of ____ &C warmer earth is an average of ____ &C warmer than if no greenhouse effect than if no greenhouse effect

average earth temp would be ____ &C average earth temp would be ____ &C instead of current ____ &Cinstead of current ____ &C

Global WarmingGlobal Warming

Global warmingGlobal warming: t_______ that the : t_______ that the accumulation of specific gaseous accumulation of specific gaseous compounds is causing an compounds is causing an uncontrollable increase in the earth’s uncontrollable increase in the earth’s temperature with potentially temperature with potentially devastating g_______ effectsdevastating g_______ effects

What is KnownWhat is Knownnaturally occurring greenhouse gases include naturally occurring greenhouse gases include w______ vapor, carbon dioxide, methane, nitrous w______ vapor, carbon dioxide, methane, nitrous oxide, and ozoneoxide, and ozoneconcentrations of most are increasing due to concentrations of most are increasing due to a______________ sourcesa______________ sourceswater vapor is the most a__________ greenhouse water vapor is the most a__________ greenhouse gas, but its concentrations are closely related to gas, but its concentrations are closely related to global temperatures and are relatively constantglobal temperatures and are relatively constant

P_________ of high concentrations of COP_________ of high concentrations of CO22 in past in past history of the Earth have been accompanied by history of the Earth have been accompanied by high temperatures at the Earth’s surface, and high temperatures at the Earth’s surface, and periods of low carbon dioxide had relatively low periods of low carbon dioxide had relatively low surface temperatures.surface temperatures.

http://www.meteor.iastate.edu/gccourse/model/co2/seedsci.html

What is knownWhat is knownsea level has risen 4-8 inches over the past sea level has risen 4-8 inches over the past centurycenturyglobal mean surface temperatures have global mean surface temperatures have increased 0.25-0.5 C since the late 19th centuryincreased 0.25-0.5 C since the late 19th centuryGreenhouse gases have long lifetimes, ranging Greenhouse gases have long lifetimes, ranging from ____ years for methane to about _____ for from ____ years for methane to about _____ for carbon dioxide to ______ years for nitrous oxide. carbon dioxide to ______ years for nitrous oxide. Anthropogenic increases in these gases could Anthropogenic increases in these gases could influence the earth’s climate for many centuries.influence the earth’s climate for many centuries. The climate system has high i_______, primarily The climate system has high i_______, primarily due to the long time scales of ocean dynamical due to the long time scales of ocean dynamical processes. processes.

http://www.meteor.iastate.edu/gccourse/model/co2/seedsci.html

What is knownWhat is known

S__________ particles that form from S__________ particles that form from sulfur dioxide emitted primarily by sulfur dioxide emitted primarily by the burning of coal contribute to local the burning of coal contribute to local cooling although the magnitude is cooling although the magnitude is uncertain. uncertain. Decreases of ozone in the lower Decreases of ozone in the lower stratosphere have contributed to stratosphere have contributed to c_______ effects in that region. c_______ effects in that region.

http://www.meteor.iastate.edu/gccourse/model/co2/seedsci.html

What we think will happenWhat we think will happenthe stratosphere will continue to c_____ as the stratosphere will continue to c_____ as COCO22 concentrations r____. Ozone depletion concentrations r____. Ozone depletion will add to the cooling. will add to the cooling. water vapor in the lower troposphere (0-3 water vapor in the lower troposphere (0-3 km) will increase about ____% for every km) will increase about ____% for every 11ooC of warming. Relative humidities will C of warming. Relative humidities will stay approximately the same. stay approximately the same. The warming of the last c_______ is The warming of the last c_______ is consistent with model projections of global consistent with model projections of global warming due to COwarming due to CO22 modified by the modified by the regional cooling effect of sulfate particles. regional cooling effect of sulfate particles.

http://www.meteor.iastate.edu/gccourse/model/co2/seedsci.html

What we think will happenWhat we think will happenD_________ of COD_________ of CO22 over pre-industrial levels (likely over pre-industrial levels (likely to occur in the later half of the 21st century to occur in the later half of the 21st century unless emissions are significantly reduced) is unless emissions are significantly reduced) is projected to lead to a global warming of 1.5 to projected to lead to a global warming of 1.5 to 4.54.5ooC (2 - 8C (2 - 8ooF). F). by 2100 we can expect temperature increase of by 2100 we can expect temperature increase of __________ooC to ____ C to ____ ooC. C. Sea-level rise is most likely to be ___ (+/-25) cm Sea-level rise is most likely to be ___ (+/-25) cm by year 2100 with continued rise beyond that by year 2100 with continued rise beyond that time highly likely. Continued high (quadrupled) time highly likely. Continued high (quadrupled) COCO22 could lead to ___+/- m rise in sea level. could lead to ___+/- m rise in sea level. Global mean precipitation will increase at ____ Global mean precipitation will increase at ____ (+/-0.5)% per 1(+/-0.5)% per 1ooC of warming. C of warming.

http://www.meteor.iastate.edu/gccourse/model/co2/seedsci.html

Is there a scientific debate over Is there a scientific debate over man-made global warming?man-made global warming?

Water vapor constitutes Earth's most significant greenhouse gas, accounting for about 95% of Earth's greenhouse effect.

Melting the ice cap Melting the ice cap was a “solution”was a “solution”

Air Pollution Control DevicesAir Pollution Control Devices

A________ towerB__________C____________ SeparatoraD___________ BedE______________ precipitatorV___________ scrubber

Air Pollution Control DevicesAir Pollution Control DevicesAbsorption Tower (Packed Bed, Spray Tower, Wet Scrubber)– D________ of the pollutant gas to the surface of the liquid– T_______ across the gas/liquid interface (dissolution)– D_______ of the dissolved gas away from the interface into

the liquid– Henry’s law:

P = HCl

– where: P = equilibrium partial pressure of gas, kPa, H= Henry's law constant, kPa⋅m3/g

and Cl = concentration of pollutant gas in liquidphase, g/m3

– want to maximize gas liquid contact by maximizing surface

area– efficiency will be limited by the solubility of the pollutant

BaghouseBaghousesame principle as the h_____ v______ c_______bags are cleaned periodically as the p______ d___ across the bag becomes excessive (approximately every 2 hours)– cleaned by mechanical r_________ (used for shake-deflate

design)– cleaned by h____ p_________ air jets (used for pulse jet

design)

must be a d____ gas streampotential f____ hazardbag "r______" with time – develops a fine mat which helps to screen out particles

for p________ removal, or used in conjunction with F____ G____ D_____________ (FGD) applications

Cyclone SeparatorCyclone Separatorused for particulates larger than ___ μmgas stream is accelerated through a s___ m_____, centrifugal force moves heavier particles out and downas the d_____ of the cyclone is reduced, the efficiency increases (as does the pressure drop)use of m________ tubes in parallel (multiclones) improves efficiency

Adsorption BedAdsorption Bedsurface p__________p______ or c________ bond with the surfaceadsorbents: activated c_____, activated a_____, silica gel, and others1 ounce of activated carbon has a surface area of ______ acresbed must be r________ prior to breakthrough

Electrostatic PrecipitatorElectrostatic Precipitatorw____ in t____ or wire and p____ configurationswet or dry, wet cleaned by w______ s____, dry by rapping, can be cleaned while in servicec_______ wire imparts an electrical charge (neg), particles are attracted to charged (pos) collecting plateshigh p__________ removal efficiencies possible

Venturi ScrubberVenturi Scrubbervelocity of gas is a_________ by a factor of four in the throat section where nozzles inject water or solutionhigh velocity causes a__________ of liquidpressure drop following the t________ section creates a lot of turbulence resulting in good intermixingrequires s_________ (e.g., cyclone) following venturi to collect particles and liquid

T___________ IncinerationT___________ Incineration

http://www.epconlp.com/blog/images/658_Site_Visit_2006_blog.JPG