What makes soot

Reactive molecules form and quickly bind with other hydrocarbons. The reaction forms the seed of the soot particle, but the process isn't done. The binding creates reactive molecules.

These reactive products bind with other hydrocarbons and cause the soot particle to grow. Soot is ubiquitous.

It can harm human health, agricultural output, and energy-consumption efficiency; on the other hand, it is also critical for some industrial processes, such as glass and tire production. This study solves the longstanding mystery of the fundamental physics of how soot forms. It may also explain interstellar-dust formation. Understanding the physics may give scientists a better chance of controlling particle generation. While all candles produce some amount of soot, a few factors make some produce more soot than others.

Below are some candles that produce excessive soot:. Getting rid of soot can be a long, tedious process. Without the right equipment it can be really difficult to get satisfactory results. Well, this is where a professional cleaner comes in. At AdvantaClean, we have years of experience in the cleaning industry. We handle everything from water damage restoration and air duct cleaning to effects due to fire and residual smoke damages like black soot.

We also offer services in smoke odor removal , whereby we help get house fire smoke smell out of your furniture. We have the tools and expertise to guarantee that the job is completed to perfection. If you need any help with soot removal, feel free to contact us today. April 11, By AdvantaClean. November 09, By AdvantaClean.

AdvantaClean Systems, Inc. Cookies help track user website behavior for functionality, analytics, and marketing and may share your information with third parties. By visiting this website you agree to our use of cookies. For more information see our Privacy Policy. What is black soot and when should you worry AdvantaClean July 20, What is Black Soot? Soot vs. Mold: How to Tell Them Apart Most people find it a little difficult to differentiate between soot and mold.

Areas Where You Might Find Soot In Your House Below are common areas that are susceptible to gathering soot; The base of the door — This mostly happens as your carpet filters it from the air On light switches and outlets — Static electricity tends to attract soot On your walls — This is often due to temperature differences in different parts of the wall leading to ghosting the creation of black spots Why Is Black Soot Dangerous?

How to Prevent Black Soot A few preventive measures can be adopted to prevent soot from accumulating in your home. It turns out that the most important characteristic of soot in determining its optical absorptivity is the spacing of adjacent carbon layers, which is an indirect measure of the amount of ordering in the particle.

When there is more order, carbon atoms are more tightly bound and lose some of their associated hydrogens. As a result, the carbons become more metal-like, meaning their electrons require less energy to move, so they absorb longer wavelengths of light.

Figure 7. Laser imaging was used to examine the internal structure of the lower 50 millimeters of test flames, revealing the flame sheet blue arrows , the soot layer yellow arrows and polycyclic aromatic hydrocarbons that are products of combustion red arrows.

The size of the resulting soot clusters, shown at bottom, depends on fuel type and flame shape. Shown here are kerosene a , ethylene b , methane c , ethylene slot flame d and methane slot flame e. The images of the soot samples in a-d are each about 1, nanometers wide, whereas e is about nanometers wide. Remarkably, we found that the mean spacing between the carbon layers was nominally the same—from 3. For comparison, the interlayer spacing of pure graphite, the most ordered form of carbon after diamond and fullerenes, is 3.

The results from this study imply that the index of refraction is essentially the same for soot from different flames, once the sooty material has hardened into solid particles. Thus, historical studies of the variation in soot absorptivity as a function of height in flames can now be understood as reflecting the variable contribution from precursor particles, which become progressively less abundant as one samples higher and higher within a flame.

At some height, only solid soot particles are present in the flame or in the emitted smoke, and the absorptivity of the soot stays constant. The results from our investigation of soot nanostructure begged the long-standing question of just what is the correct value for the index of refraction of solid, carbonaceous soot.

To get at the answer, we collaborated with investigators in Sandia's fire-research program to measure extinction coefficients the exponential factor by which light dims as it passes through a material , from which we could derive values for absorptivity and, in turn, the refractive index.

The samples were taken at different heights within laboratory flames burning methane, ethylene and kerosene a stand-in for jet fuel. Flames used were of the standard variety or were slot flames, where the plume is basically restricted to two dimensions. Slot flames heat the fuel stream more slowly, so soot would be expected to form later and mature less rapidly. The use of these flames let us explore the effect of residence time on soot formation.

Figure 8. A series of consecutive transmission-electron-microscopy images, each about nanometers wide, shows the effect of a high-power electron beam on newly formed soot and other tarry substances collected on a fibrous grid. The high-power beam is required to obtain high-resolution images.

At first, the collected soot agglomerate is well defined top, left. After 30 seconds top, right and then 60 seconds of exposure bottom , the soot starts to lose its shape. The amorphous material deposited on the grid appears to have fluidized in the high-power beam and flowed over the soot aggregate, obscuring it from imaging attempts.

It is unclear whether the soot itself also suffered some disassociation from the beam. But such results make it impossible to analyze soot or precursor particles that form in the lower parts of flames. Determining the extinction coefficient entailed extracting soot and the surrounding gases from the flames with a metal tube, capturing the soot-laden gases in a transparent cell where the dimming of a laser beam passing through could be measured, and then collecting the tested soot onto a filter for determination of its mass.

To ensure that large hydrocarbon molecules—which might condense into solids in the gas sampling and cooling process—did not influence the measurement of mass, we passed methylene chloride, a common solvent for heavy hydrocarbons, through the soot samples, which were then placed in a vacuum to remove the methylene chloride and any hydrocarbons present before they were dried and reweighed. For the soot derived from ethylene and kerosene flames, we found values for the extinction coefficient that were consistent with measurements made by other investigators of soot emitted from the tops of flames.

For the soot extracted from a methane flame, however, we found a markedly lower value. We surmised that this disagreement may be a consequence of a difference in particle size, which would affect the amount of light scattered.

Individual soot particles are usually too small to produce significant amounts of scattering, but as these particles aggregate, they can grow large enough to scatter as much as 30 percent of the amount of light they absorb. Figure 9. In a close-up about 33 nanometers wide, at a magnification of 1. The particles seem to start at one or several nucleation points and then build up around those sites in a spiral pattern.

Further measurements showed that aggregated soot particles derived from the burning of ethylene and kerosene are significantly larger than those produced by methane-fueled flames. Methane, having a simpler hydrocarbon structure than the other fuels, is less inclined to produce soot. With this knowledge of particle sizes, we were able to calculate the amount of scattering to be expected.

Whereas the larger ethylene- and kerosene-generated soot aggregates scatter 20 to 30 percent of the amount of light they absorb, the smaller methane-produced aggregates scatter only 3 percent.

This difference accounts for the amount of variation we had found in our measurement of light extinction, implying that the absorption coefficient is the same for the soot from all three types of flames—consistent with our earlier high-resolution TEM study. Taking the analysis of our laser measurements one step further, we calculated the values of the real and imaginary components of the index of refraction that are necessary to yield the absorption coefficient we had measured, using a relation originally derived by the 19th-century British physicist Lord Rayleigh for the scattering and absorption of light by small particles.

In addition, we calculated the index of refraction that would result in the amount of scattering we had measured for ethylene soot.

The result was 1. With these results, it appears that we are finally arriving at a clear understanding of just how black soot really is: Its characteristic absorptivity is larger, by about a factor of two, than what many researchers had long believed.

Soot particles therefore have a greater ability both to absorb and to emit light than was previously realized. The data have brought needed clarity to the understanding of soot optical properties as the particles evolve in both small, steady flames and large, erratic pool fires. Using these new values for how much light is extinguished as it passes though a cloud of soot, we can better estimate the amount of soot in flames and the temperature of these particles.

Knowing the temperature, concentration and emissivity of soot allows one to determine how much radiant heat is transferred from a flame, which in turn may help investigators to understand more fully the dynamics of fires, particularly large accidental ones. With this information, fuel depots might be built to safer standards, and emergency personnel may be able to make better decisions when serious problems arise.

But we also hope that such studies can aid in the appreciation of soot, a substance that can be as brilliant and useful as it can be dark and destructive. Skip to main content. Login Register. Page DOI: Stephanie Freese. Images courtesy of the authors. Image courtesy of the authors. Bibliography Bockhorn, H. Soot Formation in Combustion: Mechanisms and Models.

Berlin: Springer-Verlag. Bond, T. Can reducing black carbon emissions counteract global warming? Environmental Science and Technology Dalzell, W. Optical constants of soot and their application to heat-flux calculations.

Journal of Heat Transfer While all types of soot cause some darkening, soot can look completely black in more severe cases. Although most soot looks similar, some types can be harder to clean or cause more intense odors. Its high acidic nature can cause discoloration in paints and long term presence can also play a role in lingering smoke odors. If you believe your home or building is suffering from soot or smoke damage, you should contact a qualified professional today.

An experienced expert can help you identify any existing soot or smoke damage and create a plan for removing it.