Okey this
time I will post about the material science subjects namely Waste Gas. Did you
ever hear the word waste gas? Perhaps there who've heard it but maybe some have
not. For more details, let us refer to the explanation ..
Air pollution can be caused by natural sources
or as a result of human activity. In general contamination caused oleb natural
source known magnitude is difficult, however we may still estimate the amount
of air pollutants and activities. Air pollutants as a result of human activity,
it is generally much more predictable, especially if unknown material type,
material specifications, the ongoing process of the event, as well as the
specifications of the unit operations used in the process and post-process. Besides
the distribution of pollutants into the atmosphere can also be estimated with a
variety of approaches. How to estimate the amount of pollutants coming out of a
particular operating system, as well as the approach used to predict the
distribution of these pollutants into the atmosphere will be described in the
following discussion.Process Air PollutionAll chemical species are included or
entry into the atmosphere of a "clean" called contaminants.
Contaminants at concentrations high enough to cause a negative effect on the
receiver (receptor), when this happens, disebat contaminant contaminant
(pollutant).Diklasifihasikan air contaminants into 2 categories according to
how contaminants enter or put into the atmosphere, namely: primary
contamination and secondary contamination. Contamination is the primary
contaminant emitted directly from the source of contamination. Secondary
contaminants are contaminants that are formed by chemical processes in the
atmosphere.Sources of contamination from human activity (anthropogenic) is any
motor vehicle, facility, plant, installation or activity that emits primary air
contaminants to the atmosphere. There are 2 categories of anthropogenic
sources, namely: fixed sources (stationery source) such as: electricity generation
with fossil fuels, factories, households, services, etc. and other (mobile
source) such as trucks, buses, airplanes, and train.Five primary contaminant in
total contributed over 90% of global air pollution are:a. Carbon monoxide
(CO),b. Nitrogen oxides (NOx),c. Hydrocarbons (HC),d. Sulfur oxides (SOx)e.
Particulates.In addition there is a primary contaminant secondary contamination
is contamination that secondary impacts on environmental components or
contaminants emitted from the primary contaminant transformation into a
different form of contamination. There are several secondary contamination that
can lead to significant impacts both locally, regionally and globally, namely:
a. CO2
(carbon monoxide),
b.
Contamination smog (smoke fog) or smog (smoke fog),
c. Acid
rain,
d. CFC
(Chloro-Fluoro-Carbon/Freon),
e. CH4
(methane).
Elements of
Air Pollutantsa :
a.Carbon
monoxide (CO)Carbon monoxide pollution comes from natural sources such as
forest fires, oxidation of terpenes emitted to the atmosphere of the forest, the
production of CO by vegetation and marine life. Other sources of CO from
anthropogenic sources, namely the burning of fossil fuels contributes 78.5% of
the total emissions. Pollution from anthropogenic sources 55.3% comes from
burning gasoline in automotive.
b. Nitrogen
oxides (NOx)Important nitrogen oxide contamination from anthropogenic sources,
namely: NO and NO2. Contribution of anthropogenic sources to total emissions of
± 10.6%.
c. Sulfur
oxides (SOX)Sulfur compounds in the atmosphere consists of H2S, mercaptans,
SO2, SO3, H2SO4salts of sulfite, sulfate salts, and organic sulfur aerosols. Of
contamination is the most important thing is that SO2 contribute ± 50% of the
total emissions. Sulphate and sulphite salt contamination in the form of
aerosols from sea spray contributes 15% of total emissions.
d.
Hydrocarbons (HC)The most important hydrocarbon contamination is CH4 (methane)
+ 860 / of the total hydrocarbon emissions, which are derived from 11% rice,
34% of the swamps, tropical forests 36%, mining and others 5%. Other
hydrocarbon contamination is quite important is the terpene emissions (a-pinene
p-pinene, myrcene, d-Iimonene) ± 9.2% of the plant total hydrocarbon emissions.
Donations hydrocarbon emissions from sources antrofogenik 5% smaller than those
derived from the burning of gasoline 1.8%, and evaporation of the solvent
insineratc 1.9%.
e.
ParticulateParticulate contaminants include particles of molecular size s /
d> 10 μm.Particle size> 10 μm to be deposited by gravity from the
atmosphere, and the smaller size of 0.1 μm generally do not cause environmental
problems. It is therefore important particulate contamination is the size range
from 0.1 to 10 μm. The main source of fuel combustion particulates are ± 13% -
59% and incineration.
f. Carbon
dioxide (CO2)Contamination of CO2 emissions from fuel combustion and natural
sources. The main anthropogenic source of contamination is the combustion of
coal 52%, natural gas 8.5%, and 2.8% of forest firesg. Methane (CH4)Methane gas
is a contaminant which, together with CO2, CFCs, and N2O causes the greenhouse
effect that causes global warming. CH4 source of contamination is the rice
(11%), marshes (34%), tropical forests (36%), mining, etc. (5%). The greenhouse
effect can be understood from Figure 30. Sunlight entering the atmosphere about
51% is absorbed by the Earth's surface and partially transmitted and reflected
radiation in the form of short wavelengths (30%) and partly in the form of
infrared radiation (70%). Infrared radiation emitted by Earth's surface muffled
by clouds. Gases CH4, CFCs, N2O, CO2 in the atmosphere resulting in
pent-infrared radiation will increase which in turn will lead to global
warming.
h.
Photochemical smokescreenThe smoke haze is the result contamination
photochemical reaction between O3, hydrocarbons and NOx to form a new compound
aldehyde (RHCO) and Acil Peroxy Nitrate (PAN) (RCNO5).
i. Acid
rainWhen the concentration of NOx and SOx contamination high in the atmosphere,
it will be converted into HNO3 and H2SO4.The presence of hydrocarbons, NO2,
metal oxides Mn (II), Fe (II), Ni (II), and Cu (II) accelerates the reaction of
SO2 into H2SO4.HNO3 and H2SO4 together with HCI HCI emissions cause the degree
of acidity (pH) of rain is low <>Ambient Air PollutionAmbient air quality
is an early stage to understand the negative impact of air contaminants to the
environment. Ambient air quality is determined by:
(1) the
quantity of contaminant emissions from contamination sources,
(2) the
transportation, conversion and removal of contaminants in the
atmosphere.Ambient air quality will determine the negative effects of air
contamination on public health and welfare (plants, animals, materials and
other mark-Iain)Information on the health effects of air pollution exposure on
the data derived from animal, epidemiological studies, and in the case of a
limited study of exposure in humans. Research is continuously carried out with
the aim of:
(1)
Establish better concentration where the negative effects can be detected,
(2)
determine the correlation between human and animal responses to contamination,
(3) Obtain
more information on the epidemiology and
(4) Bridging
the information gap and reduce uncertainty standards presently applied.Ambient
air quality standard / ambient set for the contamination are: O3 (ozone), CO
(carbon monoxide), NOx (nitrogen oxides), SO2 (sulfur oxides), non-methane
hydrocarbons, and particulates. Air Quality National Quality Standard American
(Table 13) that have been reviewed by the National Academics of Science and
Environmental Protection Agency (NEPA) establishes standards of primary and
secondary standards.Primary quality standard established to protect the safety
margin is sufficient (adequate margin of safety) public health which are set to
protect the most people (15-20%) were susceptible to air pollution. Secondary
quality standard set to protect public welfare (materials, plants, animals) of
any negative effects of air pollution are known or can be anticipated.Based on
ambient air quality standard specified emission standards based on the
anticipation that the contaminant emissions under the standards and the process
of transportation, conversion, and removal of contaminants, the quality will
not exceed the ambient air quality standard. One example is the emission
standards for Steam Power Plants with Fuel Coal.Emission factorIf a certain
amount of fuel burned, it will come out a certain amount of combustion gases.
For instance, coal generally. Its chemical formula is written in the C
(carbon), when burned perfectly with 02 (oxygen) will produce CO2 (carbon
dioxide). But in fact it is not.It turned out to any coal burned also produced
other products besides CO2, which is CO2 (carbon monoxide), HCHO (aldehyde),
CH4 (methane), NO2 (nitrogen dioxide), SO2 (sulfur dioxide) and Abu.Products of
combustion than CO2, commonly referred to as a pollutant (contaminant).Emission
factor is here defined as a certain weight of pollutants generated by burning a
fuel se / ama certain period of time. From this definition it can be seen that
if something pollutant emission factors are known, then the amount of
pollutants that pass from the combustion process can be determined amount per
time unit.Distribution of pollutantPollutants emitted from the system will
spread into the atmosphere.The concentration of pollutants in the air as a
result of the distribution of pollutant emission sources can be estimated with
a variety of approaches, such as the model of a black box (black box model),
the normal Gaussian distribution model (Gaussian model), and other models.Plume
rise (smoke rising)Upward movement of clouds of gas from a height of chimney
(stack), until the smoke flowing horizontally is known as the "plume
rise" or rising smoke. The increase is due to the momentum due to the
vertical velocity and the gas temperature difference "flue gas" with
ambient air. Because of this plume rise, stack height are physically unable to
use the Gauss equation.Instead, stack height needs to be supplemented with high
rise smoke that is known the effective stack height.Correlation Between Air
Pollution and HealthAir pollution can cause health problems in humans in many
ways, such as by a factor stimulates or triggers a number of diseases. Groups
affected especially infants, the elderly and low-income groups who usually live
in big cities with housing conditions and poor environmental. Examine the
correlation between air pollution and health, is quite difficult. This is
because:
1. The
amount and type of contaminants are manifold.
2. The
difficulty in detecting contaminants that can pose a danger to the very low
concentrations.
3.
Synergistic interaction between the pollutant.
4. The
difficulty in isolating a single factor that caused, because humans are exposed
to a lot of substances harmful contaminants for a period that is long enough.
5. Illness
and death records are incomplete and unreliable.
6. The cause
of multiple and long incubation period of penyakitpenyakit (eg, emphysema,
chronic bronchitis, cancer, heart disease).
7. Problems
in extrapolating the results of laboratory experiments to the human
animal.There is a strong correlation between air pollution with chronic
bronchitis (chronic). Although smoking is almost always the highest order as a
cause of chronic respiratory disease but the sulfur oxides, sulfuric acid, particulate
matter, and nitrogen dioxide has been demonstrated as a cause and originators
brochiale asthma, chronic bronchitis and pulmonary emphysema.The results of
research in the United States sometime in the 70's showed that chronic
bronchitis affects 1 in 5 people among American men aged between 40-60 years
and the condition is associated with smoking and living in urban areas where
the air is polluted.The actual relationship between air pollution and health or
the onset of the disease it causes in fact still can not be explained clearly
very well and is a very complex problem. Many other factors that will determine
this causal relationship. However, statistical and epidemiological data from
this relationship can be seen with the real.In general morbidity of data can be
considered more important and useful than data on mortality. Moreover, the
findings of physiological abnormalities in human life that occurred before the
early signs of the disease can be seen or felt, as a result of air pollution,
clear more important meaning. Precautions should already be implemented at the
earliest possible time.WHO Inter Regional Symposium on Criteria for Air Quality
and Method of Measurement has established several concentration levels of air
pollution in relation to the consequences for the health / environment as
follows:
Level I:
Concentration and time exposed where not found any result, either directly or
indirectly.
Level II:
Concentration in which may be found on sensory irritation, harmful effect on
plants, limiting vision or other consequences adverse to the environment
(adverse level).
Level III:
Concentration where obstacles may arise in physiological functions were vital
as well as changes that may cause chronic disease or shortening of life
(serious level).
Level IV:
Concentration where possible acute illness or death in the sensitive population
groups (emergency level).Some ways to calculate / check the effect of air
pollution on health are among other records: the number of absences jobs /
services, the number of certificate / medical certificate, the number of
treatments in the hospital, the number of morbidity in children, the amount of
morbidity in elderly people , the number of troops investigation anggotaanggota
morbidity in patients with certain diseases such as heart disease, lung and so
on.Investigations should be done prospectively and the comparative between
areas with severe air pollution and light, by also taking into account other
factors that might affect (eg air, eating habits, smoking, data meteorological,
etc.).Diseases caused by air pollutionDiseases that can be caused by air
pollution are:
1)
Bronchitis chronica. The effect on women and men the same. This proves that the
prevalence is not affected by the kinds of day-to-day work. By cleaning the air
can decrease 40% of the mortality rate.
2) Emphysema
Pulmonum.
3)
bronchopneumonia.
4) Asthma
bronchiale.
5) Cor
pulmonale kronikum.In an industrial area in the Czech Republic for example, can
be found a high prevalence of this disease. Similarly, in northern India where
people live in clay houses without windows and using fire wood for home
heating.
6) lung
cancer. Stocks and Campbell found the mortality in nonsmokers in urban areas 10
times larger than rural areas.
7) Heart
disease, also found morbiditasnya 2 times greater in areas with high air
pollution. Carbon monoxide was found to cause harm to the heart, especially if
there are signs of previous ischemic heart disease. Affinity of CO for
hemoglobin is 210 times greater than the O2 so if COI-Ib levels equal to or
greater than 50%, akin to the heart muscle necrosis. Levels lower than it had
been able to disrupt the function of the heart. Scharf et al (1974) reported a
case with myocardial infarction after exposure to CO transmural.
8) gastric
cancer, found 2 times Iebih much in areas with high pollution.
9) Other
diseases, for example irritation of eyes, skin and so many are linked to air
pollution. Also children's growth disorders and hematologic abnormalities ever
published. In Russia never found barriers to influenza vaccin antibody
formation in urban areas with high pollution levels, while in other areas the
normal formation.In Japan now officially recognized by the central and local
governments, a number of 7 kinds of diseases related to pollution (pollution related
diseases). namely:
Bronchitis chronica
Asthma bronchiale
Asthrnatik bronchitis
Pulmonum emphysema and its complications
Minamata disease (due to contamination with
methyl-Hg)
Itai-itai disease (due to cadmium poisoning
khronik)
Chronic arsenic poisoning (water and air
pollution in the U.S. tambangtambang). People with a valid description of the
disease, which is thought to be caused by one of the hazards of pollution, will
receive compensation due to losses and maintenance costs of illness by
polluters.Waste GasThere are several methods that have been developed for
simplification of exhaust gas. Basic development is done is absorption,
burning, absorbing ions, neutralization and cleaning swimming
particles.Equipment selection on the basis of the following factors:- Type of
contaminants (pollutants)- Composition- Concentration- Speed of water
pollutants- The toxicity of pollutants- Density- Reactivity- Environmental
conditionsEquipment design variables are adjusted to obtain maximum
efficiency.The difficulty is often formed in inventory tool on the
market.Desired design option does not comply with the conditions of waste,
because it had formed a new design. Ability to design equipment requires
special skill and it is a problem anyway.In addition, there are other factors
that should be considered is the economic value of the equipment. Do not
include most of the investment in equipment that would have to be charged at
the cost of production. The problem is that later turned out to be a load
control consumer costs.On the basis of this reasoning the choice of technology.
Processing should be a good consumer protection policy from the point of
pollution itself and in terms of cost.In general, the type of pollutants
through the air consists of an assortment of chemical compounds in the form of
waste and toxic and hazardous materials stored in the factory.Waste gas, smoke
and dust through the air are:
1. Dust: The
form of fine solids
2. Carbon
monoxide: Gas is colorless and odorless
3. Carbon dioxide:
gas, colorless, odorless
4. Oxides of
nitrogen: gas, colorless and odorless
5. Smoke: A
mixture of gases and particles are black: CO2 and SO2
6. Sulfur
dioxide: Colorless and sharp herbau
7. Caustic
Soda: Crystal
8. Acid
chloride: The form of the solution and vapor
9. Sulfuric
acid: viscous liquid
10. Ammonia:
Gas is colorless, odorless
11. Lead:
colorless gas
12. Nitro
Carbon: colorless gas
13. Hydrogen
fluoride: Gas colorless
14. Nitrogen
sulfide: Gas, smell
15. Chlor:
Gas, solvents and smelled
16. Mercury:
Colorless, solvent
