In our rural areas, what is burned in the village is not firewood such as branches and dry firewood, but straw, soybean stalks, corn cobs, corn stalks and other stalks left over after harvesting crops. This kind of firewood can last for a long time. I remember that when I was a child, this was how we used to light fires for cooking at home. At that time, the rooms with boilers were blackened by thick smoke, and they had to be smoked every day when cooking. It was so painful that the tears flowed down. Moreover, when the eyes were very sore from the smoke, I rubbed them with my hands, and finally my face turned into a big mess.

Compared with burning natural gas or liquefied petroleum gas, which one has the least pollution to the environment?

First of all, let’s talk about what pollutants are emitted by the traditional method of making fire for cooking?

What we commonly call firewood usually includes a type of combustible materials, such as dry branches, branches that have not yet dried up, and wheat straw and other crop stalks mentioned above. If we take a closer look at the basic composition of these firewoods, this type of firewood is usually composed of carbon, hydrogen, and oxygen, so they are all environmentally friendly materials.

But when it burns, it is not environmentally friendly. As it burns, it will release a type of pollutant gases, including: sulfur oxides, polycyclic aromatic hydrocarbons (hydrocarbons), nitrogen oxides, and methane. , carbon monoxide and a large amount of carbon dioxide, particulate matter that failed to burn in time, that is, thick smoke, slowly rises. The reason why we feel it hurts our eyes is that some of these pollutants are at work.

Polycyclic aromatic hydrocarbons also pose a great health threat, and a considerable part of them are carcinogenic. Although the smoke from cooking stoves ties our homesickness, we must also recognize clearly that it is a source of pollution. .

What will happen when we use natural gas and liquefied gas? And where does this fuel come from?

Liquefied petroleum gas is a by-product of refining crude oil in refineries. It is a colorless, volatile liquid with high calorific value. Its main components are propane and butane, and other alkanes or alkanes. alkenes. Today's residents generally use the city's gas company pipeline supply, and of course gas tank supply.

This kind of fuel causes less pollution. Moreover, it is a by-product and is wasted when not used. It burns without dust and is also a relatively environmentally friendly fuel.

Relatively speaking, natural gas is more environmentally friendly. Natural gas covers a wide range of fields, including oil field gas, gas field gas, coal bed methane, and biogas. Natural gas can also be used to make liquefied petroleum gas. The main components of natural gas are Alkanes, of which methane accounts for the majority.

The source of natural gas is more environmentally friendly than liquefied petroleum gas, and natural gas is also safer than liquefied petroleum gas during use.

In short, using natural gas and liquefied petroleum gas is more environmentally friendly than burning firewood directly, and as the times progress, burning firewood will naturally gradually disappear, because people nowadays love beauty and will not When you light firewood and cook in a house full of smoke, this ray of nostalgia will eventually disappear.

With the intensification of environmental protection efforts and the improvement of environmental awareness, the concept that clear waters and lush mountains are invaluable assets has been deeply rooted in the hearts of the people, and rural areas will become more and more standardized in terms of environmental protection. Therefore, that wisp of nostalgia It will disappear eventually.

When I was a child, I lived in Huangshan, a beautiful small town in the south of the Yangtze River, which was called Huizhou more than 40 years ago. At that time, homes had both briquette stoves and wood-burning stoves. Powdered coal needs to be bought from the coal station. When the weather is good, mix some yellow mud and water to make briquettes, dry them in the sun and store them for later use. To burn firewood, you need to buy chopped firewood. Sometimes you will go to the nearby mountains to pick up some dead branches, but the trees are never allowed to be cut down.

(This is a borrowed picture, there are beauties, it doesn’t matter what the kitchen looks like, right?)

Grandma’s house is in the countryside, there is no coal stove, and they use a large iron Pot and wood stove. There was never enough straw at home, so my cousin often had to go far away on weekends or holidays to cut thatch and dig tree roots, then dry them in the yard and use them to make fires. Because every household burned firewood and grass, all the trees and grass that could be cut down on the nearby mountains were cut down. It looked like there weren't many trees.

Anyone who has used a wood stove knows that it must have a long chimney extending from the roof, otherwise it will never be used. Why? Because there was smoke, a lot of smoke. Even if there is a chimney, the walls of the kitchen are always dark. They are used to it and don't think there is anything wrong with it.

(The curl of cooking smoke is the nostalgia of many people)

In the past few years, there was haze in the north, and I was worried when winter came, because of PM2.5, a large amount of fine particulate matter pollution in the air. Among them, automobile exhaust and coal-fired power plants contribute the majority, and the rest is mostly related to household fires for heating. Burning coal produces smoke, and burning wood is even worse. Since the large-scale coal-to-gas conversion, the situation has become much better.

We all know that flowers, plants and trees are mainly composed of lignin, cellulose, and also contain a small amount of lipids, proteins, ash, etc. From the elemental composition, wood mainly contains 49.5% carbon, 6.3% Hydrogen, 44.1% oxygen, and small amounts of other elements such as nitrogen and sulfur.

Judging from the chemical composition of wood, if it is completely burned, it will indeed not cause much pollution, because most substances will be converted into carbon dioxide (CO?) and water (H?O), Very small amounts of chemicals remain in the carbon ash, which makes an excellent farm fertilizer.

The problem is that the combustion of firewood is often incomplete and a large amount of smoke is produced during the combustion process.

(When the fire is lit, a large amount of smoke will be produced because the temperature is not high enough)

Wood burning can usually be divided into three types: dry preparation, flaming burning and flameless burning. stage.

The drying preparation stage usually starts with the wood being lit. The water in the wood begins to evaporate under the action of heat. When the temperature reaches 150℃~200℃, the wood begins to decompose, producing water vapor, formic acid, and acetic acid. , carbon dioxide, nitrogen oxides, sulfur oxides, aldehydes, polycyclic aromatic hydrocarbons and other gases. At the same time, the wood will also produce a lot of smoke, and most of the above-mentioned gases will be discharged outward along with the smoke.

As the temperature further rises to 200℃~250℃, the wood begins to carbonize, producing a small amount of water vapor, methane, carbon monoxide, etc. As the temperature continues to rise, the wood begins to decompose violently, and if there is enough oxygen in the air, it will burn flammably. During the flaming combustion process, most of the volatile matter and particulate matter will be burned, so the amount of smoke will be much reduced.

(There will be less smoke when burning with flames)

When the organic components in the wood are decomposed, the evaporated combustible gas decreases, and oxygen begins to react with the carbon and gradually enters the to the flameless combustion stage until the charcoal is completely burned out. The flameless combustion stage rarely produces smoke.

(Flameless combustion)

As mentioned earlier, when wood is burned, it will produce a large amount of volatile substances and smoke. Which wood produces more smoke and which produces less smoke? Let’s first take a look at the following test chart:

(Smoke conditions of different woods under the same storage and burning conditions)

From the above table we can see that different wood species have different The density of smoke produced by them varies greatly. Among them, red pine produces less smoke, while elm, maple, birch, etc. produce much more smoke. The smoke density MSD is positively correlated with the density of the wood itself. The stronger the wood, the more smoke it emits. This is mainly because the greater the density of wood, the better its thermal conductivity. The surface temperature of the wood rises relatively slowly and the pyrolysis rate decreases, which can easily lead to incomplete combustion and reduced combustion rate.

At the same time, the moisture content of the wood itself is also closely related to the amount of smoke produced. The evaporation of moisture absorbs a large amount of heat energy, thus prolonging the process from drying preparation to flaming combustion to flameless combustion, causing Wetter wood smokes more.

A large amount of smoke particles carry sulfur oxides, aldehydes, polycyclic aromatic hydrocarbons and other gases that cannot be burned in time and are dispersed into the air. They are called "wood burning smoke particles" (WSP). WSP is related to Compounds such as polycyclic aromatic hydrocarbons will be deposited in the lungs after being inhaled by the human body. Over time, they can stimulate macrophages and epithelial cells to secrete interleukin-6 (IL-6), IL-8 and tumor necrosis factor α (TNF-α). Pro-inflammatory factors have been shown to be important causes of lung inflammation and some serious diseases.

(Now do you think the smoke from cooking over the countryside is romantic or air pollution?)

Currently, most cities and some rural areas are promoting the use of gas instead of coal and firewood, which will significantly reduce air pollution.

Urban gas is mainly liquefied petroleum gas and natural gas. Some rural areas do not have the conditions to connect to gas pipelines, but many also use bottled gas. A few places build their own biogas pools and use biogas for cooking, which is also a good idea. A good idea.

Whether burning coal gas, liquefied petroleum gas, natural gas or biogas, there is very little emission of solid particulate matter.

(Natural gas flame)

Coal gas is carbon monoxide. It reacts chemically with oxygen to produce carbon dioxide. In addition, no other chemical substances are produced. It is more environmentally friendly, but because of its calorific value It is relatively low. Nowadays, except for industrial boilers and chemical raw materials, there are few for civilian use.

The main components of liquefied petroleum gas are propane (C?H?) and butane (C?H?), as well as some other alkanes. Its calorific value is more than three times that of wood. The products after combustion are mainly carbon dioxide and water. It burns without soot and residue, and the storage and transportation conditions are not very harsh. Therefore, it is widely used as chemical raw materials and civil fuel.

Natural gas and biogas are the same thing. Its main component is methane (CH?). When methane is completely burned, it generates carbon dioxide and water vapor, so it is a pollution-free and clean fuel.

(Burning gas is much cleaner than burning firewood)

Although firewood comes from nature, and the ashes after burning can be returned to nature as fertilizer, but during the burning process It releases a large amount of smoke and some volatile polycyclic aromatic hydrocarbons and other gases. Although this smoke looks romantic, it is actually an air pollutant and can cause harm to our health.

In contrast, whether it is coal gas, liquefied petroleum gas or natural gas, they do not produce smoke and dust when burned, and there are very few harmful volatile gases. Therefore, gas is more environmentally friendly than burning firewood.

(It’s better to have less “romance” like this!)

Romance or health, which one do you choose?

Which pollutes the environment the most, burning wood or burning gas? I am a farmer and I don’t understand chemistry, but I can imagine it. People feel choked when burning firewood in closed houses. beyond a certain time. People will try to run out because it is too choking. If you add gas in a closed room. I think people will die without realizing it. From here we can find that although the smoke from burning firewood is noisy, it is much safer than invisible gas.

On the other hand, the most pollution-free energy sources in nature are solar energy, water energy, and wind energy. Because they are inexhaustible, they really do not pollute the environment at all. Apart from these three items, they should be firewood. Although it produces pollution, the carbon dioxide it produces is a gas attracted by crops and complements each other with animals. Therefore, to this day, the earth has not seen smoky weather, but smog weather as industrialization accelerates.

Let’s think about how gas is produced. Gas can be divided into two categories, one is natural gas and the other is coal gas. Everyone knows that natural gas is mined, so how is it mined? Does mining produce pollution, does refining produce pollution, and does there be no pollution from mining, production, transportation, to household use? We can’t just focus on the process of use, that is, whether the process of use produces pollution. I think it is still worth studying.

Everyone should know how firewood is produced. As the farmer's proverb says, a tree that grows for thousands of years can be used as firewood, which is history [it is said that firewood is used to burn pots. If firewood does not burn pots, it will rot in the ground Yes, it is actually pollution, it is just invisible.

From my point of view above, I think experts should stop coming up with ideas to sell gas. People in cities burn gas and people in rural areas burn firewood, just let nature take its course.

This kind of comparison is inherently malicious and deliberately causes a war of words to achieve a certain purpose. You should be able to guess the specific purpose!

Some people are always keen to analyze from professional fields, such as the utilization rate of the chemical reaction between wood burning and urban burning gas, the amount of waste emissions, etc., and there are even very professional-looking data. support.

But what is the reality? There is not much comparison between the two. Simply looking at the combustion efficiency of wood burning in rural areas and gas burning in cities, gas burning is more efficient, while wood burning due to its low efficiency often cannot be fully burned and will emit a lot of thick smoke!

But in any case, burning firewood is taken directly from nature, with almost no links in between. It can be used directly, but what about burning gas? How many steps does it take to finally reach each family? The initial exploration, development, transportation, pipeline laying... each link must involve a large amount of energy investment, and environmental pollution will inevitably occur!

Besides, burning firewood is theoretically renewable, while burning gas theoretically means less energy if you burn more, which is non-renewable! The excessive development of gas not only damages the earth's environment, but also has an impact on the earth's geological structure. This impact is long-term and even irreversible!

Our ancestors have been burning firewood for thousands of years, and they have never seen much pollution to the environment. Now that the air pollution in the environment is serious, how about burning firewood? Deliberately diverting the essence of the problem? Are you making a fuss about superficial things like burning materials and burning gas?

Environmental protection requires everyone’s participation. Urbanization and environmental pollution do not necessarily have to be equated, but no one can deny that in the past few decades, our country has sacrificed the environment in exchange for urbanization and economic development. Although we don’t want this to be the strategy, it has actually happened. What we have to do is to transform the economy and ensure the sustainable development of the environmental economy!

I am from a rural area, I also burn firewood, and of course I also use gas! From the perspective of energy conservation! In fact, it improves the heat energy utilization rate of wood stoves! More environmentally friendly than burning gas! Because after these straws, straw, and firewood are fully burned, hydrogen sulfide will appear! Less than liquefied natural gas! I have a big stove and a small stove at home! When there is a lot of food, use a big stove; when there is little, use a small stove! This way you will use a lot less firewood!

High-efficiency stoves are now available in many places! When used, it will not be worse than Qi! And the burned ashes can be used as vegetable fertilizer and recycled! After all, if you are angry, it will be a non-renewable or slowly regenerated resource!

If the main question is this comparison, then it must be that burning firewood in rural areas does great damage to the environment. From a chemical perspective, the main products produced after burning natural gas are carbon dioxide and water, while burning dry firewood produces in addition to carbon dioxide and water, there are also various harmful substances, such as solid particles and harmful gases. Friends who have lived in rural areas before You should know that the billowing smoke produced by burning dry wood is very pungent.

However, it makes no sense to compare burning wood with burning natural gas. If the rural areas are also connected to gas or farmers can afford to consume natural gas, who would want to be smoked every day. To compare the impact on the environment, wood burning in rural areas should be compared with industrial waste gas and automobile exhaust in cities. This is only fair. Today's cities have been shrouded in a lot of smog, while the countryside still has blue skies and white clouds.

Everyone has the responsibility to protect the environment. Both urban residents and rural residents have the obligation to protect the environment. However, the economic gap has caused this inequality. In the end, straw burning is prohibited in rural areas, and straw burning is prohibited. Banning the use of wood stoves is unfair to farmers. For a while, 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 is not worth the industrial waste gas in just a few decades.

Which of the two pollutes more seriously, it must be gas and natural gas. How much energy does it take to extract natural gas? How much pollution does it bring? Local geographical imbalance will increase the coefficient of disasters 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 the visibility of this kind of pollution is low, which gives people the impression that it is relatively hygienic. Don't you know that as long as the energy generated by combustion is consistent, the products of the oxidation reaction are also basically the same. However, the oxides produced by firewood are highly visible and are large particle air impurities. , but it can settle and be converted to a higher degree. The ash produced by firewood is a good multi-component fertilizer. The disadvantage is that if firewood does not burn well, there will be more carbon monoxide. This can be effectively solved by improving firewood stoves, and the source of firewood is green. Plants and green plants do not pollute, and they produce a large amount of oxygen to purify the air. The generation and burning of firewood itself is just a natural return of the self-cycle... In fact, there are much fewer people burning firewood than before. Most of the so-called pollution has little to do with burning firewood. It is mainly related to pollution from car exhaust and various smoking factories, but it is also the need for development. Which one should give way to the basic needs of life and the needs of development? I think it is better to let people freely choose according to their own abilities and needs. One method should not be forced, and the question of development needs to be straightened out

Which one is more environmentally friendly, gas or wood burning? , who has caused the least harm to the earth cannot be explained clearly with one or two good words, nor can it be explained clearly by reality. We can only let future generations comment on it based on historical objectiveness.

Whether it is burning wood or gas, it is actually a progress that humans are constantly changing their lifestyles. Let’s take the burning of firewood in rural areas as an example. In fact, farmers know best about environmental protection and reuse. The process of burning firewood by farmers is a process of making full use of firewood. First, they light a fire, use the fire to heat the firewood pot, cook the meals, and set up the stove. It makes full use of the pumping principle to allow sufficient air in the stove chamber so that the firewood can be fully burned. While cooking, it also uses the principle of the flue rising, and builds an earthen kang connected to the stove to let the smoke in the kang. Circulation in the cave also dissipates excess heat through the earthen kang of the flue, using the waste heat to heat the earthen kang for warmth. At the same time, small particles such as dust and smoke after combustion can be lowered partially in the kang hole, and then passed through The chimney is lowered a part, and at this time, generally the light coming out of the chimney is light clear smoke. This is a burning process. In fact, there is very little pollution. Besides, the firewood burned are all common green plants in the mountain countryside. After burning this year, they will grow back next year. To use that inappropriate metaphor, wildfires cannot burn them all, but the spring breeze blows them. Reborn, recycled, and started again and again, it is an inexhaustible fuel.

Gas is clean, clean and convenient. It is a mineral deposit and a better energy choice for mankind nowadays. In all comparisons, it is more convenient and cleaner than firewood, but its mining and distribution It is not uniform, and it is said to cause less pollution when used, but mining and transportation are not cost-effective. The most important thing is that it is a one-time gas that is gone after being burned. It is not like firewood that can be recycled endlessly. At the same time, mining is also It is a kind of environmental damage, and it is finished after burning. In fact, people only see the convenience of gas nowadays. The real advantages and disadvantages of gas can only be commented by future generations. It is not something that modern people can judge, and it is not the result of thousands of years of practice like firewood.

I’m afraid it’s more appropriate for me to answer this question.

First of all, we must first understand what pollution and greater impact are?

Pollution: The substances humans discharge into the environment exceed the self-purification ability of the environment, causing ecological imbalance and endangering the survival and development of humans and living things.

It’s hard to explain the huge impact. Let us understand it as a relatively large difference from the original state in a short period of time.

If you agree with the above explanation, the problem is simple. Under the same conditions, burning firewood in rural areas emits more solid particles, sulfur oxides, nitrogen oxides, etc. than burning coal gas in cities, so it has a greater impact on the global environment.

Firewood comes from natural plant growth and is a renewable energy source. If it is consumed this year, it will continue to be produced next year (based on not expanding the scale of logging). Coal gas, on the other hand, takes out the non-renewable gas that has been formed for millions of years (cannot be formed in the short term), and uses a little less. From this perspective, burning firewood in rural areas causes less pollution than burning gas in cities (because there is no pollution). The question is: Do you want city people to eat uncooked rice?

Everything always has pros and cons. The key is to make the pros outweigh the cons. Burning gas in cities is one of the least polluting ways.

If we green the environment a lot, increase the self-purification ability of nature, and use every means to save resource consumption, then human activities will have little impact on the earth's environment, and the earth, the home of mankind, will become more and more beautiful. Beautiful.

Compared with burning wood, burning gas has less impact on the global environment. Of course this refers to air pollution. Today, as the greenhouse effect becomes increasingly serious, reducing carbon dioxide emissions is equally important.

Gas burning generally burns coal gas, natural gas, liquefied petroleum gas and biogas. They generally burn very fully and do not produce huge smoke and dust 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 C4H10, and the main components of coal gas are carbon monoxide. It can be seen from the chemical composition that the main product after their combustion is carbon dioxide, which will not cause any harm to the environment at all.

In the winter in the north, due to the strong demand for heating, especially in rural areas, basically every household must burn wood for heating. The winter smog in the north is particularly serious, which is one of the main sources of pollution. Especially in basin areas with dry weather, less wind and less rain, the situation is even more serious.

Wood mainly contains carbon, hydrogen, oxygen, as well as nitrogen, phosphorus, potassium, sulfur and other elements. Since wood generally contains more or less moisture, especially wet wood, it is difficult to burn completely and will produce a large amount of smoke. The white smoke we see coming out of chimneys is actually a mixture of large amounts of water vapor, small solid particles, and toxic and harmful gases. It is one of the sources of PM2.5.

After living in the northern countryside for a long time, if you are careful, you will find that when the loose dry wood burns, it basically does not produce much smoke. It can be seen that the greater the density of wood and the higher the moisture content, the more components of incomplete combustion will be there, and the greater the smoke and dust generated.

The charcoal used in the homes of wealthy people in ancient times was made from high-density wood that was heated, dehydrated and carbonized in a closed environment. The resulting charcoal could be burned indoors without producing a lot of smoke. There used to be people who burned charcoal, but now the management is stricter, so there aren’t that many anymore.

When burning firewood, various small amounts of toxic and harmful gases will be produced. Northern rural areas like smoked bacon. If used in large quantities for a long time, it can easily cause cancer. Of course, this also depends on the individual's physical condition, and it does not mean that you will definitely get cancer. Due to financial constraints, this is the situation, so try not to eat too much smoked bacon for a long time.

There was no smog in ancient times, so why is there smog now? The main reason is that the population is exploding, and the huge demand will inevitably have an impact on the natural environment.

In addition to burning firewood in rural areas, burning large amounts of coal in urban areas will also cause great pollution. Automobile exhaust also accounts for a large part, as well as industrial production that requires a large amount of exhaust gas emissions, in addition to construction and other reasons.

From a practical observation, there is basically very little smog in rural areas, and smog is still mainly concentrated over cities, which has a lot to do with the dense urban population. The more people there are, the greater the amount of sewage emissions, and the natural air pollution becomes more serious.

It can be seen from this that burning firewood cannot be blamed as the source of smog.

Due to limited economic conditions, coal is still burned in some small cities, and firewood is still burned in many rural areas. Due to the country's vigorous promotion, some rural areas are vigorously building new biogas digesters, but the current results are not good and some have been abandoned.

(Biogas digester under construction)

Except for uninhabited areas, more than 99% of areas across the country are basically connected to electricity. Some people may wonder why rural areas do not use electricity directly. ? This is mainly limited by economic conditions. There are already many trees on the mountain, and burning firewood only requires some effort. If you use electricity, it will cost several hundred yuan more every month. Farmers' income is already meager, which invisibly increases the burden. The voltage in some areas is not very stable.

Rural residents are relatively scattered, and the cost of laying natural gas pipelines is high, so it is not practical. However, some relatively wealthy rural areas have begun to use canned liquefied petroleum gas, but they are still in the minority, and most people still burn wood and coal.

At present, straw burning is basically prohibited in rural areas, and the country is also vigorously promoting new energy vehicles, such as pure electric vehicles, to alleviate the increasingly serious pollution problem.

It can be seen that the advantages of burning gas are obvious. However, due to economic constraints, firewood burning is still a widespread phenomenon in rural areas, and it cannot be eradicated at once. Secondly, firewood in rural areas is mainly used for heating and cooking. The demand is not too large. Generally, only dead branches of trees and crop straws are used, so it will not have any impact on forestland protection.

In order to change this situation in the future, in addition to technological progress and the cost reduction of new energy, the government must vigorously promote subsidies. Only with the joint efforts of the entire society can everyone live a new life without pollution.