This article comes fromWeChat public account: CC Forum (ID: ccjt2014), the original title: “Zhang Yanguo: Let Industrialization Plug the Wings of Ecological Civilization”, speaker: Zhang Yanguo (Professor, Department of Energy and Power Engineering, Tsinghua University), the title picture comes from Visual China
Based on your thoughts on future civilization , 30 years of deep cultivating “waste”, he combined innovative waste incineration technology with ecological fertilizer preparation technology to achieve ultra-low pollutant emissions, ultra-wide treatment range, waste treatment, quality improvement and efficiency improvement. Realize the organic cycle of the industrial era of ecological civilization version 3.0, and do practical things down-to-earth.
Everyone is now economically developing, and the material is richer, the sky is not so blue, the water is not so clear, but there is more and more waste.
The food we eat does not taste as good as when we were young. Sometimes we worry about whether there is something bad for our health in the food we eat. Then these are the wastes we need to faceThe problem of disposal. In the field of waste disposal, one of the core problems is how to realize the recycling of waste, which can transform all kinds of bad things produced by industrialization into harmless and useful things. Things, and then form a good cycle of these, so that the ecology always maintains a good state so that our green water and green mountains always maintain their true colors.
When I chose this direction at the time, it was actually a bit interesting because I came from a rural area in Guangdong, and I really grew up in the green mountains and green mountains when I was young. I have a deep sense of ecology. I came to Beijing and finished my study at Tsinghua University. After studying in school, I was really troubled to choose a major at that time, but I had a feeling of my own. I studied energy and power engineering, but I was doing waste disposal later. In fact, I had already a little bit cross-field. He is an academician of the Academy of Sciences and the founder of our discipline.
I told me at the time, he said, you guys want to do this thing, but you have to sit on the bench for ten years. I was very impressed at that time. Why should you sit on the bench for ten years? This thing is very complicated and not so easy to do. What I was particularly impressed with at the time was that our trash pool was so smelly that it was impossible to do it, and I felt very deeply! We go to Europe to see other garbage dumps. The quality of the garbage is completely different from ours. This also determines that our device simply takes a mature technology from developed countries and cannot solve this problem in our country.
At that time, we had the State Key Laboratory of Coal Combustion and the National Engineering Center for Coal Combustion. It should be said that we all have a place in coal combustion internationally. At that time, some of my colleagues also told me, what are you guys doing? No, I have to go to burn garbage. What’s so good about garbage? Isn’t it a little lower in calorific value than coal? After doing it for a while, I realized that it’s not the case. Our coal is a very simple thing compared with garbage. The composition of garbage is so much that you can’t imagine. You will only know when you go to the dump.
I have ran hundreds of garbage dumps in my life, and we have ran a lot at home and abroad. That is really beyond people’s imagination, so the complexity of the problem comes from the variety of things, and Is changing.
This is because we produce, live, and consume all kinds of things, it will produce countless kinds, countless types of things that are dynamically changing components, and coal is relatively fixed. Moreover, in terms of the field, what is the person who is doing energy, and what I design, you give me what I use.
After I use it up, I pursue higher efficiency and cleaner emissions, but the waste is not like this. You have to deal with whatever is given to you, so this is very difficult. This is more than what we used to do in school. People’s imagination, so it’s definitely not a simple question, it’s actually very complicated.
How can I give it to you? You have to deal with it, and at the same time you have to do a good job of emissions, and the cost is not too high, but I want horses to run and horses to eat less grass. In fact, it’s a bit challenging, so when facing these problems, I kept asking myself a question, can I build a stove and put everything together and clean it up, instead of saying that I take a class of things. For example, use a stove for domestic garbage, another for municipal sludge, another for industrial waste, another for the kitchen, and another for the kitchen. Can you clean up everything? This can be done to a large extent solve.
If the fuel is more adaptable, the economy will be better. Of course, the waste discharge is always required to be particularly good. In other words, it can be burnt, but it must be burnt very clean. So after two to thirty years of research and development, we have found a trick to gradually improve, because I am a person who has a divergent thinking, and often thinks the other way around. For example, we used to burn garbage in the grate furnace, it is like this A combustion process, a circulating fluidized bed is another combustion process, then can I reverse it? If you want to put a lot of things in a stove, you can’t follow a conventional way, saying that one-on-one and two-on-two will not solve this problem.
So I thought at the time that when we used to burn garbage in a circulating fluidized bed, we all required a uniform and stable temperature, but a lot of contradictions came about. If you burn this kind of thing, when you burn plastic, it is even and stable. But if you want to burn tree heads, bark, sawdust, branches, these things may not work, and give you a piece of waste tires may not work. it is good. We put these things together to see if we can handle it well, and I conceived a special thing.
I extracted the characteristics of the various stoves here. After I finished the extraction, can I combine two or three stoves into one stove, so we made one called Turbulent Fluidization The technology of bed gasification and incineration, after this turbulence, will take your original various waste materials with different reaction speeds. I will make it into something with the same reaction speed, and then produce some intermediate products. , Is the combustible gas, this gas passes through a high-temperature combustion, how high is it, 1000℃, 1100℃, 1200℃. The standard in our country is 850℃, and the standard in the European Union, Japan, and the United States is 850℃ or 950℃. We can burn it to 1000℃ or 1200℃. After burning it at a very high temperature, it will burn thoroughly.
The other thing is that there are some low melting points in the garbage, such as sodium and potassium. These alkali metals are easy to melt, so the temperature is very low, so we made a very uneven one in the whole One thing is the other way around. This immediately solves the most critical problems in the requirements we just mentioned. It is said that you can put all the garbage in a stove according to the curve I set. At the same time, it was all disposed of, and finally we made a 250-ton furnace, which ran beyond our expectations.
After the operation was over, the Japanese were still a bit unconvinced. They formed a group of more than 20 people to see if our technology was bragging and whether it could be done. We won technically!
We won this project, and we achieved a few firsts. One is that we are in this project. After all the things are added, we can have a very continuous and stable temperature change.The direction is very small. Although it is uneven, the high should be high and the low should be low. This is the place where the Japanese are most unconvinced. They say that this is impossible. A stove must not be like this. It always fluctuates. , In our place is very stable.
Secondly, our temperature can be as high as 1100°C, so we burnt the garbage here. We are very sensitive to dioxin. What is this dioxin? It is the most toxic known on earth Substance, its toxicity is 1,000 times that of our potassium cyanide, so everyone thinks this thing is too terrible, here is the early standard of our country, the emission of dioxin is 1.0 ng per standard cubic meter, the European Union, Japan and us 2014 The national standard that was implemented in 2010 is 0.1 nanogram per standard cubic meter. How much can we achieve now? 0.01 ng per standard cubic meter.
So even though we are a very local industry, this thing is difficult to do, but we have been at the forefront here to deal with these things, so our results are published in international journals and international conferences. Later, my doctoral students and I won awards. At this time, I don’t know why they sent the email. I even threw it directly into the trash mailbox. I waited until the professors from several universities in our peers called me. You really won the prize. I said it was a lie, the other side said it was not. Because it is not an application by itself, it shows that our international counterparts are very recognized by us.
We burnt the garbage. Our green waters and mountains actually have another problem. We have more than 1,000 counties, and there are many rural and township populations in each county. We have 600 million people. There is still about one ton of trash in these counties every year, and hundreds of millions of tons of farmed manure. We eat meat very casually now, just like the old landlord’s wealth. You can eat whatever you want. , But what is behind this? There will be a lot of farming manure emissions, and these things are not only large in quantity, but the composition is also different from the traditional things raised by our family, soThis will bring some new challenges, and the green water and green mountains must not be left behind.
So when we do it here, the varieties that should be available in counties, villages, and towns are the same as those in big cities. We can use the incinerator just mentioned before for what can be burned. Well, we have the best one. The incinerator can solve this problem, and our furnace should be more complete in function, that is, it can not only burn everything, but also large or small, as small as 50 tons, 500 tons or even 1,000 tons. Taiwan stove.
The remaining problem is that we have so many farms as mentioned earlier. The other is a large amount of straw, including forestry waste, as well as the things brought by agricultural production. The impact of these things is not only It pollutes the environment, and we grow vegetables directly, compost directly, and do other things will bring some practical obstacles, such as what to do with the virus here, can it be controlled, can it be eliminated, including us There are a lot of antibiotics and hormones in farming. How can they be eliminated, and then don’t enter the food chain again, and be able to recycle relatively clean and reliable fertilizers.
So this is a new problem that we need to solve. Here I also crossed another world. This is accidentally ran from energy to environment, and from environment to agriculture. I teach my students When I asked them two questions, I went to the thermal energy project to teach students how to design a power plant. I said I will give you a piece of meat. Is the energy released when you eat it in your stomach and throw it into the stove? The same, the student wondered if it was the same, some said the same, some said it was different, and then I said that the hot stuff we use here can also be used as fertilizer. This idea is totally out of bounds.
If you think your power generation has something to do with fertilizer, I told him a basic idea of mine. Because of what I do, I do supercritical hydrolysis when the temperature and pressure are very high. Above the critical point of, this substance will have some very strange properties, but if we use it to treat this manure and find a way to turn it into fertilizer, we have to make it cheaper and not too expensive.
So we will cool it down. Under a pressure of more than ten kilograms, at 200°C, it can be made of pure and hot fertilizer without adding any other chemical substances. Beautiful, what is the advantage of this crossover? It combines the strengths of the people who used to be heat-burning people and some of the needs mentioned earlier, so that it really solves the problem. For example, the problem of antibiotics just mentioned. The antibiotics decompose at 78°C to 80°C. When I reach 200°C, they are gone in just one second.
Living body, no matter what kind of virus you are, diseases, and other insect eggs or things, at 200°C and a dozen atmospheres, all are gone in a few tenths of a second.
Okay, so it will be completely broken down later. What’s so good about this technology? It is also possible to make our lignin, cellulose, pectin, and starchy things sufficiently small molecules, so that the fertilizer produced in this way is stable once, and it does not need to be piled, so we claim that we don’t use this technology. Fermentation. Once the fertilizer is made without fermentation, it is very fast. How fast is it? We start from the raw materials, the truck that pulls the manure, and the truck that pulls the straw into the factory for unloading. After three to four hours, you will directly pull the fertilizer away. .
At this time, it was completely industrialized. It overturned our traditional composting three days, five days, fifteen days, or even sixty or seventy days of anaerobic conditions. These are not needed. These methods are processed. The quality of the fertilizer is very good, what’s the good thing? We can’t just say that the vegetables we grow let farmers use good indicators. Our organic matter requirement for the national standard is 45%, and we can reach 80%.
National standard nitrogenWe have achieved 5% of beneficial elements such as phosphorus, potassium, and nearly 10%. So after this fertilizer is used, after we plant it by local farmers, not only does it not grow insects, the key is that the yield is very high and the taste is very good. So when everyone eats it, they think it is the taste of childhood dishes, such as tomatoes and cucumbers.
The output is high, the quality is good, and you can take the road of large-scale industrialization, and quickly dispose of all your original manure waste. At this time, a complete set of waste treatment just mentioned is formed. In the process of treatment, the one that should be burned is burned for you, and the one that should be processed into fertilizer is processed into fertilizer. When these two are added together, it becomes waste treatment.
In our two technologies, there is no need to add other fuels. All of them are waste garbage, sludge, bark, sawdust, and straw. Then there is manure or fertilizer made by adding some straw. , So it can perfectly solve our current problems. In the waste disposal in rural and county areas, in fact, in addition to technical problems, there is a big challenge, that is, who pays and who pays.
In this case, in the past, it used to rely on fees and government financial subsidies. So why the sewage and garbage disposal in our county has always been an old and difficult problem. In addition to technical problems, it is mainly an economic bottleneck. Our model There is a unique advantage in it. Not only is it technically using waste to treat waste, but also turning waste into treasure. After it becomes valuable organic fertilizer, it can feed back the entire public welfare system.You can run. To exaggerately say that if the horse is good, now the horse does not need to eat grass. I just need to dispose of this waste for you.
Under our new conditions, for example, we are now engaged in garbage sorting, and we can burn everything that we used to be. After sorting, it will be better. We can burn the ones that should be burned, and we can make fertilizers. , So our entire technology and future development will definitely bring us a better prospect.
We have made these two sets of new technologies in 20 to 30 years, supported by dozens of invention patents, and also have application cases at home and abroad. This way, I believe it will contribute to the development of our future ecological civilization, especially It is under the conditions of industrialization that we use the ideas and concepts of ecological civilization to govern, we can live a very rich material, and at the same time enjoy a life of green waters and mountains.
This article comes fromWeChat public account: CC Forum (ID: ccjt2014), Lecturer: Zhang Yanguo (Professor, Department of Energy and Power Engineering, Tsinghua University)