TOBA DE EŞAPAMENT FĂRĂ FUM Options

[Democratos]

Anul trecut, la expoziţia de la GENEVA, România a obţinut o medalie de aur pentru o realizare originală, referitoare la o tobă de eşapament care nu evacuează fum. Distruge fumul în PM10 şi gaze, demonstraţie şi model funcţional.

Voi, specialiştii în domeniu, ce părere aveţi, şi asta este o mistificare?

DEM

[f1anatic]

Imi permit sa fac citeva observatii vis-a-vis de discutia celor implicati aici. In limitat timpului EXTREM DE REDUS, este foarte posibil ca aceasta sa fie unica mea interventie in aceasta discutie. Imi cer scuze daca nu voi putea fi in stare sa particip la dialog si daca nu voi reusi sa abordez fiecare subiect stiintific legat de aceasta inventie.

Voi incepe cu o explicatie a fumului de esapament. Si nu in priviinta compozitiei deoarece puteti cauta foarte usor pe Google. Toata lumea a inteles ca e format din carbon organic (OC) si inorganic (EC), sulfati (SOx) , nitrati (NOx), CO, CO2, H2O iar metodele de control actuale se bazeaza pe conversia catalitica in 3 etape si un raport stoichiometric aer/fuel de aproape 14.7 care minimalizeaza formarea de substante nocive.

Explicatia pe care doresc sa o ofer este in priviinta marimii acestor particule. Domnul Democratos a afirmat ca gazele (fumul) de esapament sint de marimea PM10 ceea ce este incorect. Sint in preponderenta PM 0.1 - PM1.0 - mult mai mici.

Sa incepem cu ceva "background".

Aceasta este distributia marimilor particulelor.

Iar aici sint puse in perspectiva

Impreuna cu terminologia acceptata in USA


Si definitiile de rigoare

PM10
The U.S. EPA defines PM10 as particulate matter with a diameter of 10 micrometers collected with 50% efficiency by a PM10 sampling collection device. However, for convenience in these modules, the term PM10 will be used to include all particles having an aerodynamic diameter of less than or equal to 10 micrometers.
PM10 is regulated as a specific type of "pollutant" because this size range is considered respirable. In other words, particles less than approximately 10 micrometers can penetrate into the lower respiratory tract. The particle size range between 0.1 and 10 micrometers is especially important in air pollution studies. A major fraction of the particulate matter generated in some industrial sources is in this size range. PM10 is discussed in more detail in Module 6.

PM2.5
As with PM10, EPA defines PM2.5 as particulate matter with a diameter of 2.5 micrometers collected with 50% efficiency by a PM2.5 sampling collection device. However, for convenience in these modules, the term PM2.5 will be used to include all particles having an aerodynamic diameter of less than or equal to 2.5 micrometers.
EPA chose 2.5 micrometers as the partition between fine and coarse particulate matter. Particles less than approximately 2.5 micrometers are regulated as PM2.5. Air emission testing and air pollution control methods for PM2.5 particles are different than those for coarse and supercoarse particles.

In general distributia marimilor particulelor se face prin realizarea unei histograme, care arata procentul de particule in fiecare interval. Doar ca Axa X este pe scara logaritmica Spre exemplu:


Daca este analizata distributia particulelor atmosferice, aflii de regula ca este bi-sau tri- modala datorita diferitelor metode de formare a particulelor (pe care nu il voi discuta). Particulele produse de emisia motoarelor diesel au o asemenea caracteristica bi-modala.


SURSA: US EPA
http://epa.gov/apti/bces/module6/matter/matter.htm
http://epa.gov/apti/bces/module3/index.htm

Mai jos este un marunt sumar la contributia emisiilor de la automobile la "poluarea" atmosferica in Statele Unite.

Automobile traffic is characterized by releases of certain metals as well as elemental and organic carbon, sulfates and nitrates (Cadle et al.,1999a,b; Chen et al., 2002; Ogulei et al., 2005). Diesel and gasoline engines are distinguished
by different ratios of elemental (EC) to organic (OC) carbon: gasoline engines have an approximately equal ratio while diesel engine emissions are characterized by a large EC to OC ratio along with the presence of metallic elements including Fe, Ba, Ca, Zn which come from engine-oil additives or brake wear (Cadle et al.,1999a,b; Ogulei et al., 2005; Lee and Hopke, 2006; Qin et al., 2006; Gildemeister et al., 2007; Kim et al., 2007; Hammond et al., 2008). Diesel powered transportation source contributions to PM2.5 mass vary by location and car pool profile: in Baltimore they are estimated at 1% of PM2.5 mass (Ogulei et al., 2005); in Metro New York City 3-15% (Qin et al., 2006); 4-8% in Metro Detroit (Gildemeister et al., 2007); 5% in Metro St. Louis (Lee and Hopke, 2006); 2-9% in Seattle WA (Kim and Hopke, 2008). Gasoline (spark ignition) emissions are
estimated to contribute up to 26% of PM2.5 mass in Baltimore, MA (Ogulei et al., 2005); 15-20% in Metro Detroit (Gildemeister et al., 2007); 21% in Metro St. Louis (Lee and Hopke, 2006); 13-31% in Seattle,WA (Kim and Hopke, 2008). Motor vehicle traffic as whole accounts for 31-35% of PM2.5 in Detroit, MI (Hammond et al., 2008); 17% in Metro St. Louis, MO (Lee and Hopke, 2006) but only 2.5% of PM2.5 mass in rural site of Athens, OH (Kim et al., 2007). It is also possible to associate vehicle emissions with specific activities: in Detroit, MI both Gildemeister et al. (2007) and Hammond et al. (2008) were able to correlate diesel emissions within the city with the Port of Detroit; the rail yards and the truck traffic on Ambassador Bridge ? the busiest US-Canada border crossing. Diesel and gasoline emissions also exhibit week-day to week-end variability, and
the trend is more obvious for diesel emissions (Lee and Hopke, 2006; Wu et al., 2007; Kim and Hopke, 2008).

Bun. Si deci ce marime au particulele din gazul de esapament ?

Typical particle size distribution of diesel exhaust is shown in figure 4-4. Modes are nucleation (Dp < ca. 50 nm), accumulation (ca. 50nm < Dp < 1 um), and coarse (Dp > 1 um). Most of the particle mass is in the accumulation mode between the 0.1-0.3 um diameters.

http://ec.europa.eu/transport/roadsafety_l...iculates_d2.pdf

The size and composition of the fine particulate matter emitted, averaged over all of the catalyst-equipped gasoline powered vehicles tested, is shown in Figure 2.The particle mass distribution peaks at approximately 0.1-0.2 um in particle diameter and is mainly composed of organic compounds accompanied by small amounts of elemental carbon, sulfates, and trace elements.

The size and composition distribution of particles collected from the noncatalyst-equipped gasoline-powered
vehicles is shown in Figure 3. The peak in the mass distribution occurs between 0.1 and 0.2 um particle diameter. Particle composition analysis reveals that particles of all sizes emitted from noncatalyst-equipped gasoline vehicles
are chiefly composed of organic compounds.

The size and composition distribution of particles collected from medium-duty diesel-powered vehicles is shown
in Figure 4. Particle size distribution measurements made by the electronic instruments are reported only from the
DMA/CNC combination because the optical particle counter is not calibrated to measure light-absorbing soot particles
accurately.The particle mass distribution for this source peaks at approximately 0.1 um particle diameter and consists of
almost equal amounts of elemental carbon and organic compounds.

Source: Kleeman et al. Size and Composition Distribution of Fine Particulate Matter Emitted from Motor Vehicles. Environmental science and Technology, vol. 34, issue 7, pp 1132-1142, 2000.

TOTEMS particle number distributions were measured from 5.6-562 nanometers using an Engine Exhaust Particle Sizer
(EEPS) and total 3-3000 nanometer (0.003 - 3.0 um) particle counts were measured using an Ultrafine Condensation Particle Counter (UCPC) with 1-second temporal resolution during cold start and on-road driving.

http://www.uvm.edu/~transctr/publications/...010/10-3038.pdf

Ca sumar ca deja a expirat timpul acordat acestei activitati: sursele de combustie, in general, si in particular particulele eliberate de motoarele cu combustie interna sint incadrate in categoria fine (<=0.1 um) si ca distributie acopera plaja intre 0.01 um si 1 um, in nici un caz PM10. Acest lucru contravine afirmatiilor domnului Democratos de pe prima pagina. Aceasta este pozitia Agentiei de Protectia Mediului si a miilor de cercetatori din Statele Unite. Concluziile le trageti dvs.

Am citat lucrarile de mai sus deoarece aveau poze usor de gasit si de folosit si pe intelesul tuturor, nu sint nici singurele ci singurele la care am avut access in computer FARA sa incep sa intru pe Science Direct si Sci-Finder scholar. Documentele de baza care analizeaza sursele, compozitia si distributia poluarii cu particule in USA se afla aici
http://www.epa.gov/ttnnaaqs/standards/pm/s_pm_cr.html
si reprezinta cunostiintele cumulate ale miilor de cercetatori din Statele Unite si luate in evidenta de Agentia de Protectia Mediului din USA actuale la vremea ultimei evaluari a NAAQS (National Ambient Air Quality standards) care se face la fiecare 5 ani. Aceste documente dateaza din 2006. Documentul care are sumarul care a devenit lege este
PM NAAQS Final Federal Register Notice (Preamble and Regulatory Text). Pentru cei care se doresc aventurosi, le propun sa citeasca sectiunea PM2.5 (in USA se controleaza PM2.5 si PM10). Gazele de esapament sint incluse in PM2.5. Pentru cei care sint lenesi si doresc doar un 2-3 slide-uri dintr-un Power Point
http://www.arb.ca.gov/research/health/healthup/jan03.pdf
iar daca vor sa citeasca despre efectele asupra sanatatii
http://enhs.umn.edu/current/5103/particles/character.html
iar daca vor sa se documenteze in priviinta unui studiu care a analizat relatia intre particulele ultrafine (deci sub-micronice) si automobile, proiect sponsorizat de EPA nu are decit sa o faca aici
http://cfpub.epa.gov/ncer_abstracts/INDEX....t/6984/report/F
concluzia lor este:

It is now well established that increases in the concentration of fine particulate matter (PM2.5) in urban areas are associated with increases in morbidity and mortality. It is not known what components of PM2.5 cause these effects, but one candidate is the ultrafine particles (UF). These are particles less than 100 nm or 0.1 ?m in size and are found near combustion sources, such as motor vehicles. In an urban environment motor vehicle emissions usually constitute the most important source of UF.

Nu comentez asupra meritelor tehnologiei tobei; cel putin NU acum; poate la anul prin Noiembrie cind voi avea timp. Atita doar mai spun: ca metoda de control a poluarii cu particule, incinerarea, arderea lor indiferent ca este facuta prin plasma rece, calda sau la bricheta nu este una din ele acceptata in momentul de fata la scara larga. Incinerarea si degradarea termica a emisiilor nocive se face pentru a controla VOC (volatile organic carbons), cu alte cuvinte a componentelor in stare gazoasa, nu a celor solide. PM10 se controleaza de altfel destul de usor.

Gata la revedere. Voi mai contribui aici la anul.

Pentru cei ce doresc sa citeasca mai mult, recomand:

Dr. William Hinds - Aerosol Technology: properties, behavior and measurement of airborne particles, 1999

Dr. James Vincent - Aerosol sampling: science, standards, instrumentation and applications, 2007

Wayne T Davis, Editor - Air Pollution Engineering Manual, 2000

U.S. EPA - Air Pollution Training Institute - Basic Concepts in Environmental Sciences - Module 3: Particle Formation
http://epa.gov/apti/bces/module3/formation/formate.htm#intro

U.S. Environmental Protection Agency. Air Quality Criteria for Particulate Matter
Volume I of II. Office of Research and Development, National Center for
Environmental Assessment-RTP. EPA/600/P-99/002aF: 1-900, 2004.

U.S. Environmental Protection Agency. (2006b). "EPA-CASAC-LTR-06-003.
Clean Air Scientific Advisory Committee Recommendations Concerning
the Final National Ambient Air Quality Standards for Particulate Matter."
Retrieved 3 January, 2009, from
http://yosemite.epa.gov/sab/sabproduct.nsf...33;OpenDocument

U.S. Environmental Protection Agency. National Air Quality: Status and Trends
through 2007. EPA-454-R-08-006: 1-48, 2008c.

U.S. Environmental Protection Agency. National Ambient Air Quality Standards
for Particulate Matter; Final Rule; Part II. 40 CFR Part 50, Code of Federal
Regulations - 71: 61144-61233, 2006a.

U.S. Environmental Protection Agency. The Plain English Guide to the Clean Air
Act. Office of Air Quality Planning and Standards: 1-27, 2007.

This post has been edited by f1anatic: Apr 30 2011, 03:54 PM

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