Compared with burning natural gas and liquefied petroleum gas, which of these cooking methods has the least pollution to the environment?
First of all, let's talk about what pollutants are emitted by traditional cooking methods.
Firewood, as we commonly call it, usually includes a combustible substance, such as the above-mentioned dry branches, branches that have not dried up, crop straws and so on. If we carefully study the basic components of these firewood, this firewood is usually composed of carbon, hydrogen and oxygen, so it is an environmentally friendly material.
However, when it burns, it is not environmentally friendly. With the combustion, a class of pollution gases will be released, including sulfur oxides, polycyclic aromatic hydrocarbons (hydrocarbons), nitrogen oxides, methane, carbon monoxide and a lot of carbon dioxide. Particulate matter that cannot be burned in time, that is, smoke, rises slowly. The reason why we feel hot eyes is because some pollutants are at work.
Among them, polycyclic aromatic hydrocarbons (PAHs) also pose a great threat to health, and a considerable part of them are carcinogenic. Although the smoke from kitchen chimneys restricts our homesickness, we should also clearly realize that they are pollution sources.
And what happens when we use natural gas and liquefied gas? Where do these fuels come from?
Liquefied petroleum gas is a by-product of refining crude oil in refineries. Colorless volatile liquid with high calorific value. Its main components are propane and butane, as well as other alkanes or olefins. Now residents generally use the pipeline supply of city gas company, and of course the supply of gas tanks.
This fuel causes less pollution. Besides, it is a by-product, which is wasted when not in use, and it burns without dust, so it is also a relatively environmentally friendly fuel.
In contrast, natural gas is more environmentally friendly. Natural gas covers a wide range, including oilfield gas, gas field gas, coalbed methane and biogas. Natural gas can also be used to make liquefied petroleum gas. The main component of natural gas is alkanes, of which methane accounts for the majority.
Natural gas is more environmentally friendly than liquefied petroleum gas and safer in use.
In short, using natural gas and liquefied petroleum gas is much more environmentally friendly than burning firewood directly, and with the progress of the times, burning firewood will naturally disappear gradually, because people now love beauty and will not light firewood to cook in a smoky room, and this homesickness will eventually disappear.
With the strengthening of environmental protection and the improvement of environmental awareness, the concept that clear water and green mountains are priceless has been deeply rooted in people's hearts, and rural areas will become more and more standardized in environmental protection. Therefore, that homesickness will eventually disappear.
When I was a child, I lived in Huangshan, a beautiful town in the south of the Yangtze River. It was called Huizhou more than 40 years ago. At that time, there were both briquette stoves and wood stoves at home. Pulverized coal needs to be purchased from the coal station. When the weather is fine, mix some yellow mud and water to make briquettes. After drying, store it and use it slowly To burn firewood, you need to buy firewood, and sometimes you will go to the nearby mountains to pick up some dead branches, but trees are absolutely not allowed to be cut down.
This is a borrowed painting. It doesn't matter what the kitchen looks like if there are beautiful women, does it? )
Grandma's family is in the countryside, and there is no coal stove. She uses a big iron pot and a wooden stove. There is always not enough straw and straw at home. My cousin often needs to go far away on weekends or holidays to cut thatch and dig roots and dry the fire in the yard. Because every household burns firewood, all the trees and grass that can be cut down in the nearby mountains have been cut down, and there are not many trees in the past.
Anyone who has used a wood stove knows that it must have a long chimney protruding from the roof, otherwise it will never be used. Why? Because there is smoke, a lot of smoke. Even with chimneys, the walls of the kitchen are always dark. They are used to it, and they don't think there is anything wrong with it.
(Curling smoke is the homesickness of many people. )
A few years ago, it was foggy in the north and I was worried in winter. Because of PM2.5, a large number of fine particles in the air are polluted. Among them, automobile exhaust and coal-fired power plants contribute a lot, and most of the rest are related to burning fire for heating. Burning coal has smoke, and burning wood is even worse. Things have been much better since coal was changed to gas on a large scale.
We all know that flowers and trees are mainly composed of lignin and cellulose, but also contain a small amount of lipids, protein and ash. In terms of elemental composition, wood mainly contains 49.5% carbon, 6.3% hydrogen, 44. 1% oxygen, and a small amount of other elements such as nitrogen and sulfur.
Judging from the chemical composition of wood, if it is completely burned, it will not cause too much pollution, because most substances will be converted into carbon dioxide (co? ) and moisture (h? O), a very small amount of chemicals will remain in carbon ash, which is a good agricultural fertilizer.
The problem is that the burning of firewood is often incomplete, and a lot of smoke will be produced during the burning process.
When the fire is lit, a lot of smoke will be produced because the temperature is not high enough.
Wood combustion can usually be divided into three stages: drying preparation, flaming combustion and flameless combustion.
The drying preparation stage usually begins with the burning of wood, and the moisture in wood begins to evaporate under the action of heat. When the temperature reaches 150℃~200℃, wood begins to decompose, producing gases such as water vapor, formic acid, acetic acid, carbon dioxide, nitrogen oxides, sulfur oxides, aldehydes and polycyclic aromatic hydrocarbons. At the same time, wood will also produce a lot of smoke, most of which will be discharged with the smoke.
With the temperature further rising to 200℃~250℃, wood began to carbonize, producing a small amount of water vapor, methane, carbon monoxide and so on. With the increasing temperature, wood begins to decompose violently. If there is enough oxygen in the air, it will burn with flame. In the process of flaming combustion, most volatiles and particles will be burned, so the smoke will be reduced a lot.
There will be less smoke when there is a flame burning.
When the organic components in wood are decomposed, the evaporated combustible gas decreases, and oxygen begins to react with carbon, and gradually enters the flameless combustion stage until the charcoal is completely burned out. Smoke is rarely produced in flameless combustion stage.
(Flameless combustion)
As mentioned above, when wood is burned, it will produce a lot of volatile substances and smoke. Which kind of wood produces more smoke and which kind produces less smoke? Let's first look at the following test chart:
(Smoke emission from different wood under the same storage and combustion conditions)
As can be seen from the above table, the smoke density produced by different kinds of wood varies greatly, among which Korean pine produces less smoke, while elm, maple and birch produce much more smoke. The smoke density MSD is positively related to the density of wood itself. The stronger the wood, the more smoke it produces. This is mainly because the greater the density of wood, the better its thermal conductivity, the slower the surface temperature of wood rises and the slower the pyrolysis speed, which is easy to cause insufficient combustion and slow the combustion speed.
At the same time, the moisture content of wood itself is also closely related to the amount of smoke, and the evaporation of water absorbs a lot of heat energy, thus prolonging the process of wood from drying preparation to flaming combustion to flameless combustion, resulting in more humid wood smoke.
A large number of smoke particles are scattered into the air with sulfur oxides, aldehydes, polycyclic aromatic hydrocarbons and other gases that cannot be burned in time, which is called "wood burning smoke particles" (WSP). After being inhaled by human body, compounds such as WSP and polycyclic aromatic hydrocarbons will be deposited in the lungs, which can stimulate macrophages and epithelial cells to secrete interleukin -6(IL-6), IL-8 and tumor necrosis factor -α (TNF-α) over the years.
Now, do you think the smoke from the stoves in the countryside is romantic or air pollution? )
At present, most cities and some rural areas are promoting the use of natural gas instead of burning coal and firewood, which will greatly reduce air pollution.
City gas is mainly liquefied petroleum gas and natural gas. Some rural areas have no natural gas pipelines, but many people also use bottled natural gas. It is also a good idea to build biogas digesters in a few places to cook with biogas.
No matter burning coal gas, liquefied petroleum gas, natural gas or biogas, it rarely produces solid particulate emissions.
(Flame of natural gas)
Gas is carbon monoxide, which reacts with oxygen to produce carbon dioxide. But also does not generate other chemical substances, and is more environment-friendly. But because of the low calorific value, there are fewer people except industrial boilers and chemical raw materials.
The main component of liquefied petroleum gas is propane (C? h？ ) and butane (c? H) and some other alkanes. Its calorific value is more than three times that of wood, and the products after combustion are mainly carbon dioxide and water, and there is no smoke and waste residue when burning, and the storage and transportation conditions are not so harsh, so it is widely used as chemical raw materials and civil fuel.
Natural gas and biogas are the same thing, and its main component is methane (CH? ), methane generates carbon dioxide and water vapor after complete combustion, so it is a clean fuel without pollution.
Burning natural gas is much cleaner than burning wood.
Although firewood is taken from nature, the ashes after combustion can be used as fertilizer to return to nature, but a lot of smoke and dust and some volatile polycyclic aromatic hydrocarbons and other gases will be released during combustion. Although these smoke and dust look romantic, they are actually an air pollutant, which will do harm to our health.
In contrast, whether it is coal gas, liquefied gas or natural gas, they will not produce smoke and dust when burning, and there are few harmful volatile gases, so gas is more environmentally friendly than firewood.
(such "romance" is still less good! )
Romance and health, which do you choose?
Who pollutes the environment the most, burning wood or gas? I am a farmer. I don't know chemistry, but I can imagine. When burning firewood in a closed room, people feel suffocated. For a period of time. People will try to run out because it is too suffocating. If you add gas in a closed room. I think people will die unconsciously. From here, we can find that although the smoke produced by wood burning is disturbing, it is much safer than invisible gas.
On the other hand, the most pollution-free energy sources in nature are solar energy, hydro energy and wind energy. Because they are inexhaustible, there is really no pollution to the environment, except for these three, it should be firewood. Although it will produce pollution, the produced carbon dioxide is a gas attracted by crops and has a supplementary effect on animals. Therefore, the smog weather did not appear on the earth until today, but industrialization accelerated the smog weather.
Let's think about how gas is produced. Gas can be divided into two categories, one is natural gas and the other is gas. Everyone knows that natural gas is mined, so how to mine it? Does mining produce pollution? Does training produce pollution? Does mining, production, transportation and household use not produce pollution? We can't just focus on the process of use, that is, whether there is pollution in the process of use. I think it is still worth studying.
Everyone should know how firewood is produced. As the agricultural proverb says, a tree will burn for a thousand years, which is history. [firewood is rotten in the ground when it is not ripe. In fact, it is also pollution, but it is just invisible.
From what I have said above, I think experts should stop trying to sell natural gas. City people burn gas and country people burn firewood, so let it be.
This contrast is inherently malicious, deliberately causing a war of words to achieve a certain purpose, and everyone should be able to guess what the specific purpose is!
Some people are always keen to analyze from professional fields, such as the utilization rate of chemical reaction between wood combustion and city gas combustion, waste emissions, etc., and even have seemingly very professional data to support it.
But in fact? There is not much comparability between the two. From the combustion efficiency of rural wood-burning and urban gas, gas efficiency is higher, while wood-burning is inefficient and often burns insufficiently, which will emit a lot of smoke!
But in any case, firewood is taken directly from nature, and there is almost no link in the middle. You can use it directly, but what about burning gas? How many links does it take to finally reach every family? Initial exploration, development, transportation and pipeline laying ... every link will definitely have a lot of energy input, and it will inevitably cause environmental pollution!
Besides, burning wood is renewable in theory, and burning gas is rare in theory, which is not renewable! The over-exploitation of gas not only destroys the environment of the earth, but also affects the geological structure of the earth, which is long-term and even irreversible!
Our ancestors burned firewood for thousands of years and never saw much pollution to the environment. Now the environmental air pollution is serious, take firewood as an example. What is the essence of intentional transfer? Make a fuss about burning materials and gas?
Environmental protection needs everyone's participation. Urbanization and environmental pollution don't have to be equated, but no one can deny China's strategy of sacrificing the environment for urbanization and economic development in the past few decades. Although we don't want to do this, it has actually happened. What we have to do is economic transformation to ensure the sustainable development of environmental economy!
I'm from the countryside, and I also burn wood. Of course, I use gas! As far as conservation of energy is concerned! In fact, improve the heat utilization rate of wood stoves! Environmentally friendly than burning gas! Because these straws, straw, firewood, after full combustion, hydrogen sulfide these things! Less than LNG! I have a big stove at home, a small stove! When there are many dishes, the stove is big, and when there are few dishes, the stove is small! This will save a lot of firewood!
Now there are efficient stoves in many places! That's as good as gas! And the burnt ash can also be used for cooking and recycling! If you are angry, you can't regenerate resources after all. Let's regenerate resources slowly!
If this is the main topic, then it must be that burning firewood in rural areas is harmful to the environment. From a chemical point of view, natural gas mainly produces carbon dioxide and water after burning, while burning dry wood will produce various harmful substances except carbon dioxide and water, such as solid particles and harmful gases. Partners who have lived in the countryside before should know that the smoke generated by burning dry wood is very pungent.
However, it makes no sense to compare burning wood with burning natural gas. If the countryside is ventilated or farmers can afford natural gas, who wants to be smoked every day? Compared with the environmental impact, rural firewood burning is fairer than urban industrial waste gas and automobile exhaust gas. Now the city has been shrouded in a lot of smog, while the countryside is still blue sky and white clouds.
Protecting the environment is everyone's responsibility. Both urban residents and rural residents have the obligation to protect the environment. However, the economic gap has caused this inequality. In the end, burning straw and using firewood stoves are forbidden in rural areas, which is unfair to farmers. For a period of time, the impact of rural areas on the environment can be said to be minimal. Thousands of years of slash-and-burn cultivation on the earth could not match the industrial waste gas in just a few decades.
If you want to say which of the two is seriously polluted, it must be gas and natural gas. How much energy is needed to exploit natural gas? How much pollution does it bring? Unbalanced local areas will increase disaster factors such as earthquakes. How much air will be polluted by the production, transportation and installation of natural gas transportation and storage? It's just that this kind of pollution has low visibility and intuitive hygiene. Don't you know that as long as the energy generated by combustion is consistent, the products of oxidation reaction are basically the same, but the oxide generated by firewood has high visibility and belongs to large particle air impurities, but it can sink and transform to a high degree. The ash from firewood is a good multi-component fertilizer. The disadvantage is that firewood doesn't burn enough carbon monoxide, which can be effectively solved by improving the firewood stove. The source of firewood is green plants. Green plants have no pollution and produce a lot of oxygen to purify the air. The production and burning of firewood itself is only a natural return of self-circulation ... In fact, there are far fewer people burning firewood now than before. The so-called pollution has little to do with wood burning, mainly automobile exhaust and all kinds of smoking factory pollution, but that is the need of development. Which needs to give way, basic needs or development needs? I think it's better to let people choose freely according to their own abilities and needs. We should not force them to take which road, and why we should straighten out the problem of development.
Who is more environmentally friendly, gas or firewood, and who is less harmful to the earth, can not be clearly stated in one or two sentences, nor can it be clearly stated in reality. Only later generations can objectively comment on history.
Whether it is burning wood or gas, it is actually a kind of progress that human beings are constantly changing their lifestyles. Take the burning of firewood in the countryside. In fact, farmers know best about environmental protection and reuse. The process of farmers burning firewood is a process of making full use of firewood. First of all, we light a fire, heat the firewood pot with a big fire, and make full use of the principle of pumping time to make there is enough air in the stove chamber to make the firewood burn fully. When cooking, we use the rising flue to build a heatable adobe sleeping platform connected with the stove, and let the smoke in the hole of the heatable adobe sleeping platform. It is also to radiate excess heat through the heatable adobe sleeping platform in the flue and heat the heatable adobe sleeping platform with waste heat. At the same time, it can also reduce some small particles such as dust and smoke after the combustion of adobe sleeping platform, and then reduce some of them through the chimney. At this time, the smoke from the chimney is generally faint. This is a burning process, but the pollution is very small. Let's talk about firewood, which is a common green plant in mountainous rural areas. Burn it this year and it will grow again next year. To use an inappropriate metaphor, wildfire never completely devours them. They grow taller in the spring breeze, and they are recycled and are inexhaustible fuel.
Gas, clean, clean and convenient, is a mineral deposit and a better energy choice for human beings at present. Compared with firewood in all aspects, it is more convenient and cleaner, but it is uneven in collection and distribution, with less pollution when used, but it is not cost-neutral. Most importantly, it is a disposable gas, which will be burned out and will not be endless like firewood. At the same time, mining is also a kind of environmental destruction, burning. In fact, people only see the convenience of gas at present, and the way to truly show the advantages and disadvantages of gas is only judged by future generations. This is not something that modern people can judge, nor is it the result of thousands of years of practice like firewood.
I'm afraid it is more appropriate for me to answer this question.
First of all, we must figure out what is more polluting and influential.
Pollution: The substances discharged by human beings to the environment exceed the self-purification ability of the environment, resulting in ecological imbalance and endangering the survival and development of human beings and organisms.
It's hard to explain the impact. Let's understand it as a very different state in a short time.
If you agree with the above explanation, the problem will be simple. Under the same conditions, burning firewood in rural areas emits more solid particles, sulfur oxides and nitrogen oxides than burning gas in cities, which has a great impact on the global environment.
Firewood comes from the growth of natural plants and is a renewable energy source. It has been consumed this year and will continue to be exported next year (on the premise of not expanding the scale of logging). Gas, on the other hand, is non-renewable after millions of years (it can't be formed in a short time) and is used less. From this point of view, burning firewood in rural areas is less polluting than burning gas in cities (because there is no pollution). The question is: Do you let city people eat raw rice?
Everything has advantages and disadvantages, and the key is that the advantages outweigh the disadvantages. Burning natural gas in cities is one of the least polluting ways.
If we greatly green the environment, increase the self-purification ability of nature, and try our best to save the consumption of resources, then the impact of human activities on the earth's environment will be very small, and the earth, the home of human beings, will become more and more beautiful.
Of course, compared with wood burning, gas burning has little impact on the global environment. Of course, this refers to air pollution. In today's increasingly serious greenhouse effect, it is equally important to reduce carbon dioxide emissions.
Gas generally burns coal gas, natural gas, liquefied petroleum gas and biogas, and it is generally full when burned, and it will not produce huge smoke like firewood. At present, cities mainly burn natural gas and canned liquefied petroleum gas.
The main components of natural gas and biogas are methane CH4, the main components of liquefied petroleum gas are butane C3H8 and propane C4H 10, and the main component of gas is carbon monoxide. As can be seen from the chemical composition, the products of their combustion are mainly carbon dioxide, which will not cause any harm to the environment at all.
In winter in the north, because of the strong demand for heating, especially in rural areas, basically every household has to burn firewood to keep warm. The winter smog in the north is particularly serious, which is one of the main pollution sources. Especially in the basin area, the weather is dry and there is little wind and rain, and the situation is more serious.
Wood mainly contains carbon, hydrogen, oxygen, nitrogen, phosphorus, potassium, sulfur and other elements. Because wood generally contains more or less moisture, especially wet wood, it is difficult to burn completely and will produce a lot of smoke and dust. The white smoke we see in the chimney is actually a mixture of a lot of water vapor, small solid particles and toxic and harmful gases, which is one of the sources of PM2.5
Living in the northern countryside for a long time, if you are careful, you will find that loose dry wood will basically not produce too much smoke when burning. It can be seen that the greater the density of wood, the higher the moisture content, the more components of incomplete combustion, and the greater the smoke produced.
The charcoal used in ancient rich people's homes is made of high-density wood heated, dehydrated and carbonized in a closed environment. The generated charcoal can be burned indoors without producing a lot of smoke. Someone used to burn charcoal, but now the management is stricter, not so much.
When burning wood, it will also produce a small amount of toxic and harmful gases. Northern rural areas like smoked bacon, which is easy to cause cancer if used in large quantities for a long time. Of course, it depends on your physical condition, which does not mean that you will definitely get cancer. This is the case due to economic constraints. Try not to eat too much bacon for a long time.
There was no smog in ancient times. Why is there smog now? Mainly due to the skyrocketing population, huge demand will inevitably have an impact on the natural environment.
In addition to burning wood in rural areas, burning a lot of coal in cities will also cause great pollution. Automobile exhaust also accounts for a large part, as well as industrial production that requires a lot of exhaust, as well as construction and other reasons.
From the actual observation, there is little smog in rural areas, and the smog is mainly concentrated over the city, which has a great relationship with the urban population density. The more people there are, the greater the pollution and the more serious the natural air pollution.
It can be seen that the source of smog cannot be attributed to burning firewood.
Due to limited economic conditions, some small cities are still burning coal, and many rural areas are still burning firewood. Due to the vigorous promotion of the country, some rural areas are vigorously building biogas digesters, but the effect is not good at present, and some of them have been abandoned.
(Biogas pit is under construction)
Except for no man's land, more than 99% of the country has basically realized electrification. Some people may wonder why electricity is not directly used in rural areas. This is mainly limited by economic conditions. There are many trees on the mountain, and it takes only a little effort to burn wood. If electricity is used, it will cost several hundred yuan a month, and the income of farmers is already meager, which invisibly increases a burden. The voltage in some areas is not stable.
Rural residence is scattered, and laying natural gas pipelines is costly and impractical. However, some wealthy rural areas have begun to use canned liquefied petroleum gas, but it is still a minority, and there are still many people burning wood and coal.
At present, the burning of straw is basically prohibited in rural areas, and the state is also vigorously promoting new energy vehicles, such as pure electric vehicles, to alleviate the increasingly serious pollution problem.
Therefore, the advantages of gas are obvious. However, due to the limitation of economic conditions, firewood burning is still a common phenomenon in rural areas and cannot be killed at present. Secondly, firewood burning in rural areas is mainly used for heating and cooking, and the demand is not too great. Generally, only dead branches of trees and crop straws are used, which will not have any impact on forest land protection.
In order to change this situation in the future, in addition to technological progress and the cost reduction of new energy, the government should also vigorously promote subsidies. With the joint efforts of the whole society, everyone can live a new life without pollution.