Abstract: With the gradual formation of modern industrial industry, human beings have also developed some habitual behaviors and practices. For example, boiler smoke, automobile exhaust, this seems inevitable and justified. Today, it is time to break the cage of inertia thinking through the renewal of ideas, and make a revolution in our industrial production process, so as to fundamentally solve the problem of carbon emissions and other polluting gas emissions, recycle pollutants, and make full use of heat and energy at the same time, so as to achieve the comprehensive goals of emission reduction, energy conservation and efficiency improvement.

First, the status and harm of carbon emissions

Since the industrial revolution, a large amount of carbon dioxide emitted by human activities has caused a global warming trend, and the Arctic ice and snow have also accelerated to melt, causing frequent extreme climate disasters and seriously endangering human survival and development. For global warming, scientists have basically reached the understanding that the temperature rise in the last 50 years is mainly caused by the increase of greenhouse gases such as carbon dioxide. Because carbon dioxide is a greenhouse gas that can last for a long time, its emissions must eventually drop to near zero.

China is currently the largest carbon emitter in the world. With the development of economy, it will continue to increase in the future. Although the total carbon emissions in China are still increasing, the growth rate of emissions has "steadily decreased" by about 30% since 2005, and even slowed down to near zero in 20 14. The average energy efficiency of power plants in China is also at the world leading level. China promises that its carbon dioxide emissions will peak around 2030, and it is expected to reach/kloc-0.5 billion tons at the maximum. As the largest emitter of carbon dioxide in the world, China will invest more than 4 1 trillion yuan to achieve this goal.

Second, the source and control of carbon emissions

The carbon emission caused by human activities is the main factor of the sharp increase of greenhouse gases! Human carbon emissions mainly come from the use of fossil fuels and other industrial production. From 1960 to 20 12, the cumulative emissions of coal, natural gas, oil and cement accounted for 39.2%, 17.2%, 40.5% and 3. 1% respectively. The ratio of 20 12 is 42.8%, 19.0%, 33.0% and 5.2% respectively. In recent ten years, due to the rapid growth of coal use, coal emissions have also increased rapidly.

As can be seen from the above data, the emissions of fossil fuel energy production and utilization account for 2/3 of greenhouse gas emissions, and the fundamental way to reduce carbon emissions is to reduce the consumption of fossil fuels! Energy is that foundation of economic growth. It is necessary to ensure world economic growth and energy security, solve the problems of food, clothing, housing and transportation for more than 7 billion people, and take into account the different national conditions of countries and gradually reduce their dependence on fossil fuels.

At present, all developing countries are also facing a dilemma, that is, not only to develop their economies, but also to cope with and slow down climate change. Under the existing technical conditions, if carbon emissions are reduced, it means that they have to bear the huge cost of economic slowdown or even stagnation. This is meaningless in reality and morality. This is especially difficult for China. Even if a more active energy policy is adopted, including increasing the proportion of renewable energy such as oil and gas and clean energy, China's coal consumption will still account for about 60% by 2020.

Third, carbon emission absorption and fixation.

The content of carbon dioxide in the earth's air is less than 0.03%, which has remained basically unchanged for a long time. In the natural ecosystem, the rate at which land plants and marine organisms absorb and fix carbon from the atmosphere and water through photosynthesis is basically the same as the rate at which natural environmental organisms, volcanoes, hot springs and other emission sources release carbon dioxide into the atmosphere, and carbon dioxide is always in a dynamic equilibrium state of "increasing while consuming".

80% of carbon dioxide in the atmosphere comes from the breathing of people, animals and plants, and 20% comes from the burning of fuel. 75% of carbon dioxide scattered in the atmosphere is absorbed by groundwater and atmospheric precipitation such as oceans, lakes and rivers and dissolved in water. Another 5% of carbon dioxide is converted into organic matter through plant photosynthesis and stored. Now, with the rapid development of industry, the carbon accumulated in the stratum for millions of years is released in a short time, which destroys the original carbon cycle balance. It is estimated that the natural consumption and fixation of accumulated carbon dioxide will take 50~ 100 years.

There is no better way for human beings to rely on the natural consumption of the environment for trace greenhouse gases such as carbon dioxide in the air. What we can do is to increase and strengthen the capacity of ocean and land to absorb, fix and store carbon.

Fourth, theoretical innovation of emission reduction.

In addition to protecting the marine environment and protecting terrestrial vegetation to help the environment increase its ability to absorb carbon dioxide, what human beings can do is mainly to reduce carbon emissions. At present, there are several technical directions and options to reduce carbon emissions.

1, using clean energy.

The first method is to use clean fossil energy with low carbon content. However, there are many problems in replacing coal with natural gas and shale gas. First, the use of fossil energy, there is a problem of exhaustion; Secondly, although the carbon content ratio has decreased, it still has half of the emissions; Thirdly, some experts believe that the water vapor emitted by such fossil fuels is one of the causes of urban smog, because fog has the physical conditions for haze, and the water content in local air increases, which is easy to form "aerosol" of pollutants with climate change. This is haze!

Then there is the development of non-fossil energy, such as nuclear energy, hydropower, wind power and solar energy. However, in terms of total power supply, the proportion of renewable energy is still very small. Globally, new renewable energy sources, namely wind energy and solar energy, still account for less than 5% of the world's main energy supply. 1990, the proportion of fossil fuels in global power supply is 88%, and the proportion in 20 12 is 87%. The academic circles have also raised many questions about the environmental and ecological changes and grassland desertification brought by wind energy, and the pollution and efficiency of solar photovoltaic in the industrial chain. Whether these energy supply methods are the ultimate way out for mankind is still inconclusive.

Using low-carbon energy and renewable energy is obviously the way out, but there are too many factors involved in a country's energy structure, which cannot be solved overnight.

2. Improve energy efficiency.

At present, the whole society advocates energy conservation and emission reduction, and calls on everyone to realize a low-carbon life by changing energy habits and participate in actions to save the environment and save mankind itself. However, personal capacity is limited, and per capita energy consumption in a few developed countries remains high for a long time. From a certain perspective, this road is obviously not a good way out!

The traditional concept of energy utilization is used to consuming energy to meet energy demand, and the means of energy saving and emission reduction are also used to pursuing the utilization rate of 100% as much as possible in the process of energy consumption. Such ideas and methods have been unable to achieve a large proportion of energy saving and consumption reduction in high energy consumption links. The level of social energy consumption will only increase with the development of economy and society.

The well-known law of conservation of energy makes many of us ignore the "leverage" effect of using a technology called "heat pump". That is, some energy is consumed to drive the reuse of existing heat in other media to obtain the same heat energy, but the newly consumed high-grade energy and petrochemical fuel are greatly reduced. Through the flow of energy, instead of simple energy consumption, substantial energy saving and emission reduction can be realized.

There are many kinds of heat pump technologies. The air conditioning refrigeration system adopts compression heat pump system. Air conditioning can efficiently transport indoor and outdoor heat back and forth, and the energy efficiency ratio is generally more than three times. In other words, it saves energy by more than two thirds compared with the method of directly consuming energy materials to obtain heat! People have used air conditioners and refrigerators for more than 100 years, and water source heat pumps and ground source heat pumps, which are gradually popularized in these years, are also typical applications of this principle.

There are too many kinds of heat pumps, and the energy sources that drive heat pumps include electric energy, thermal energy and potential energy. The output of the existing heat pump system can easily reach above 100℃, and it involves the high energy consumption link of "water-steam" boiling, and it runs efficiently for a long time. If our boiler can strive for the efficiency of 100% from now on, and start with the efficiency of 200% ~ 300% or even higher, it will save energy by more than 50%, and it will consume energy materials from the original need of heat. Obtained from efficient recycling and transportation in other links, the new energy consumption and environmental heat removal of the system are only one-tenth and one-tenth of the original direct energy consumption mode, which greatly improves the energy utilization efficiency.

In fact, it is almost impossible for human energy resources to increase exponentially, and it is entirely possible to reduce social energy consumption by one-third, two-thirds or even more through technological innovation! As long as we work hard to "make energy move", the law of conservation of energy can ensure that human beings have inexhaustible energy, and there is no danger of global warming.

3. Develop the basic theory of energy utilization.

At present, the theoretical circle is studying new theories and new energy sources, but no one has reflected and studied the basic theories of traditional energy sources and energy applications. At present, about 70% of electricity in China is provided by thermal power, but the working principle of thermal power generation is still based on Rankine cycle, which was born more than 100 years ago and hardly developed! Cars and planes still use Carnot cycle, and there is no breakthrough. Even today, Rankine cycle still generates 90% of the world's electricity, including almost all solar thermal energy, biomass energy, coal and nuclear power plants.

Philosophically speaking, the birth time of Rankine cycle has certain historical limitations. There is a great gap between the mechanical conditions of that era and the theory of fluid mechanics, and there are inevitably some theoretical limitations and cognitive deficiencies. Even the law of conservation of energy has developed to the conservation of mass and energy, and it is still developing, so Carnot cycle and Rankine cycle are impeccable and perfect?

In fact, more than one hundred years of technological progress have proved the development and innovation of Rankine cycle. Injection technology can realize the reuse of exhaust steam after doing work with the help of non-mechanical power, and the theory of compressible fluid thermodynamics can also enable us to directly recover and reuse the condensation heat released by the condensation of exhaust steam that cannot be directly used, so that the heat that cannot be converted into work at one time of the steam turbine has the opportunity to participate in the next work cycle, and the overall thermal efficiency of the steam power cycle can be greatly improved in theory after many times of conversion and work.

We put forward "new steam power cycle" to try to realize "energy movement", and also re-understand and apply Carnot cycle innovatively, and put forward "heat engine cooling". It is hoped that this will bring new explorations in the theoretical circle, change the main mode of energy application, improve the efficiency of heat engines, and achieve substantial energy conservation, emission reduction and efficiency improvement in various industries.

4. Carbon capture and resource utilization

L carbon capture

The premise of carbon dioxide utilization is how to obtain carbon dioxide resources continuously and stably, and the technology in this area has basically matured. It is difficult to collect carbon from a large number of scattered CO2 emission sources, so the main target of carbon capture is centralized CO2 emission sources, such as fossil fuel power plants, steel plants, cement plants, oil refineries and synthetic ammonia plants.

First of all, there is a way to increase the concentration of carbon dioxide in tail gas by "oxygen-enriched combustion", which is convenient for efficient recovery. Carbon capture can be realized by direct cooling and compression. For all kinds of waste gas with different carbon dioxide content, corresponding recovery methods have also been formed, including low temperature distillation, membrane separation, catalytic combustion, pressure swing adsorption and so on.

This paper will put forward a simple, efficient, environmentally friendly and low-cost condensation recovery method, which can be applied to carbon dioxide-containing waste gas with various concentrations and different components, and can also recover other greenhouse gases and harmful gases.

L carbon sequestration

In recent years, people try to concentrate and liquefy the collected carbon dioxide, and then bury it deep underground and deep under the sea. But in the long run, this is just an "ostrich policy", and the carbon that can be treated is very small compared with the digested and fixed carbon in nature, which also leaves a serious ecological crisis.

Another method is to use metals and metal compounds to react with carbon dioxide to generate metal solidified products for storage. The reaction process can also release heat, which is an alternative combustion process. It usually needs to be realized at a temperature above 2000℃ or higher, but the situation of producing other more complex pollutants will be more serious. At present, the industry technology has not made much progress.

L carbon utilization

Carbon dioxide can be used in food, chemical industry, fire protection, agriculture, petroleum, artificial rainfall and many other fields. Its value can be reflected from the price of 600~800 yuan per ton.

The utilization of carbon dioxide as a chemical raw material has begun to take shape. Urea is the largest product for fixing carbon dioxide, followed by inorganic carbonate, and is also used to make alkali, sugar and degradable plastics.

Although carbon dioxide is an excellent fire extinguishing agent, it is not widely used in practice, especially in large-scale conventional fires (such as forest fires) or general hazardous chemicals fires (such as hazardous chemicals fires in Tianjin Binhai New Area), and it has a very good fire extinguishing effect. It should be further popularized and applied in the future, and a large amount of carbon storage has been realized at the same time.

Carbon dioxide is an indispensable raw material for photosynthesis of green plants. In a certain range, the higher the concentration of carbon dioxide, the stronger the photosynthesis of plants, so carbon dioxide is the best gas fertilizer. Experiments show that carbon dioxide is effective for the vigorous growth and maturity of crops. During these two periods, if carbon dioxide gas is sprayed twice a week for 4-5 times, the yield of vegetables, rice, soybeans and sorghum can be increased by 90%, 70%, 60% and 200% respectively. We can use this method to "fertilize" the forest, actively promote the growth of vegetation, and greatly increase the ability of environmental green plants to absorb carbon dioxide.

The collected carbon dioxide is either stored at low temperature or at high pressure. According to our "heat engine cooling" theory, solid and liquid carbon dioxide can also absorb free heat in the environment or other media, vaporize and expand into high-pressure gas, which is used to promote mechanical work. The existing internal combustion engine can become a "pneumatic machine" with a little modification in the laboratory, using high-pressure carbon dioxide gas as the power source. Experiments show that the volume of liquid carbon dioxide is 5~8 times larger than that of gasoline, but the comprehensive cost is half or similar to that of gasoline, which has commercial value of popularization and application.

Imagine that in the near future, an ocean-going freighter, carrying a large amount of liquid carbon dioxide as a medium, absorbs the heat of seawater, expands into high-pressure carbon dioxide gas, becomes the power source of the ship, and finally discharges into the sea, increasing the carbon absorption of the ocean and reducing the wave resistance, killing two birds with one stone! A modified bus and locomotive carries liquid carbon dioxide. When passing through mountain roads and grasslands, start the pneumatic mode. Carbon dioxide absorbs the heat of the surrounding air and becomes high-pressure carbon dioxide gas to continue to push the vehicle forward. The discharged carbon dioxide tail gas has become "gas fertilizer" for green plants in alpine grassland.

Five, condensation recovery of carbon emissions

Although the existing gas condensation collection is a common means, there are few specific applications of absorbing waste gas and polluted gas with very low boiling point by using extremely low temperature. We propose a method of cooling and condensing industrial tail gas and waste gas with complex components by stages by using ultra-low temperature cold source, which can liquefy the greenhouse gases contained in the tail gas, preliminarily separate them and store them in categories, which can turn waste into treasure, further centralize treatment and realize zero emission of tail gas. At the same time, the sensible heat and latent heat contained in the tail gas can be converted into electrical energy and mechanical energy.

1, using liquid air cooling source.

Liquid air cools the air below its boiling point, and the air changes from a gaseous state at room temperature to a liquid state close to -200℃. Using this liquid as a cold source, the waste gas is cooled by the device, and finally the high-boiling carbon dioxide and other gases are liquefied and solidified, and the low-boiling liquid air is exhausted after endothermic gasification. Through liquid replacement, pollutants and greenhouse gases in waste gas can be collected. system

The schematic diagram is as follows:

The waste gas enters the air-cooled evaporator from the waste gas inlet to further cool down, then enters the regenerative heat exchanger (such as plate-fin heat exchanger or sleeve heat exchanger) to gradually cool down with the treated cold air, and then further cools down in the heat exchanger; When the low-temperature condenser reaches the lowest temperature, the carbon dioxide in the exhaust gas is condensed, and the treated clean gas returns to the regenerative heat exchanger, and the newly entered exhaust gas is precooled by using the low temperature of the exhaust gas, so that the cold energy can be fully utilized, and finally recovered to be close to the inlet temperature and then discharged; Liquid air is pumped into the low-temperature condenser by a low-temperature pump as a cold source, and at the same time absorbs heat and vaporizes into high-pressure gas. After further heat exchange by the heat exchanger, it enters the expander to do work and drives the generator to generate electricity. The gas discharged from the expander also enters the regenerative heat exchanger to pre-cool the inlet air. The water vapor in the waste gas is condensed and then sprayed into the air-cooled evaporator for evaporation, which improves the utilization rate of cold energy.

The equipment cost of such a system is about per ton 15000 yuan; Using 1Kg,-19 1℃, liquid air with vaporization heat of about 37 and gas specific heat of 0.25 can absorb heat again after the expander does work to generate electricity, which can replace about 0.6Kg carbon dioxide with vaporization heat of -78℃ and 137 and generate electricity at the same time. The wholesale price of 1 ton of liquid air is 150 yuan, and the recovered 0.6 ton of carbon dioxide can generate 150 kwh of electricity according to the wholesale price of 650 yuan, with a gross profit of about 3 15 yuan; A small amount of concentrated sulfate and nitrate solution can also be recovered.

2. Utilization of heat pump cold source

Using the existing two-stage refrigeration compression heat pump system, it is easy to realize the output of -80℃. Using this cold source, the waste gas is refrigerated by the device, so that gases such as carbon dioxide in the waste gas are liquefied and solidified, and the collection of polluted gases and greenhouse gases with boiling points lower than the temperature of the cold source in the waste gas is realized. The schematic diagram of the system is as follows:

Exhaust gas enters a regenerative heat exchanger (such as a plate-fin heat exchanger or a double-tube heat exchanger) from the exhaust gas inlet, and the treated cold air is gradually cooled until the low-temperature condenser reaches the lowest temperature, so that carbon dioxide in the exhaust gas is condensed, and the treated clean gas returns to the regenerative heat exchanger, and the newly entered exhaust gas is precooled by using the low temperature of the exhaust gas, so that the cold energy is fully utilized, and finally recovered to be close to the inlet temperature before being discharged; The condensation heat is transferred by the heat pump to the hot water in the water storage tank for standby.

The equipment cost of such a system is about 3000 yuan/kWh; Electric energy 1KwH, the cost is 0.5 yuan, the refrigeration efficiency is 0.85 (theoretical value is 2), the output is about 7 14Kcal, and about 4.4Kg of carbon dioxide with vaporization heat -78℃, vaporization heat 137 and gas specific heat of 0.25 can be recovered, and the wholesale price is 650 yuan/ton, with a value of 2. At the same time, it can also output 2Kg steam at 120℃ or 3 1Kg hot water with a temperature rise of 50℃. Calculated by 25 yuan per ton of hot water, it is worth about 0.7 yuan and Maori 3 yuan.

According to the report of China-EU cooperation project on near-zero emission of coal utilization at the end of 2009, the cost of carbon dioxide capture is 18 Euro/ton, and the comprehensive cost of carbon dioxide capture and storage is 25-30 Euro/ton. The scheme proposed in this paper is close to or even lower than the existing data, and the comprehensive effect is better.

From the analysis of the above two ways, it is good economy, low equipment cost, strong versatility, short payback period, great social promotion value and high enterprise enthusiasm!

The prospect of the implementation stage of intransitive verbs

In the process of popularizing and applying the above-mentioned carbon collection and recovery scheme, we should first start with the relatively concentrated carbon emission. Such as various boilers, kilns and large internal combustion engines.

For example, the flue gas that should be discharged should be obtained from the smoke outlets and chimneys of heating boilers, industrial steam boilers and coal-fired boilers in power plants, and the pollutants and greenhouse gases in them should be recovered. The equipment used in the heat pump cold source system is a mature system in the industrial field, and the refrigeration cold source can be produced from several kilowatts to several thousand kilowatts. The heat exchange system and condenser are also mature products, and the low-temperature storage tank has national standards for a long time, and large-scale production will soon be realized. In the process of installing and trying out this system, there is no need to reform the original production system, which has good feasibility, safety and easy engineering. The installation, debugging and putting into use of the system can be implemented step by step to achieve a smooth transition. It can also be started and stopped flexibly in the subsequent use process. Because of its good economy, the enthusiasm of enterprise transformation and use will be easily mobilized, and market-oriented operation will easily integrate the production capacity, funds and resources of all parties.

Liquid air cold source method has the characteristics of simple system, auxiliary power and power output, and is suitable for automobile exhaust gas recovery. The government can take the lead in demonstrating, giving priority to the trial use of urban public transport and sanitation vehicles, and gradually extending them to key transport units, logistics and other enterprises, so that they can obtain better economic benefits from fuel saving and the sale of renewable resources while reducing emissions.

Enterprises that have the conditions to use carbon dioxide as a power medium to release carbon dioxide to the ocean, forest, grassland and other environments can be further rewarded and compensated to achieve the purpose of benefiting the country, enterprises and the environment.

Seven. Concluding remarks

A biologist put a flea in a glass. This "high jump champion" who can jump 400 times his height jumped out rudely. Later, the experimenter put a glass cover on the glass mouth, and the unsuspecting fleas kept hitting the glass cover. After constant impact, the flea adapted to this height and never hit the glass cover again. At this time, the experimenter took away the glass cover. Only to find that this flea can never jump out of the cup again. A week later, the situation remained the same. This flea can only jump to this height. Afraid of hitting your head, afraid to jump again? I'm used to it. I'm too lazy to dance anymore? Or have you acquiesced that this cup is beyond your reach? It seems to be bound by the successful experience summed up by oneself through personal practice.

Today, we humans can't be that flea. We need to break the inertia thinking, reorganize the traditional industrial production process that we are used to, use the achievements of technological progress, re-understand the basic theory and technological process, realize innovation and development, and make another "leap" that can give full play to our capabilities! We need to change energy, power and emissions to completely solve the problems of effective utilization of energy and resources and environmental pollution.

References:

1 Li fenfen, etc., carbon dioxide capture in power plant flue gas, chemical engineering and technology 20 1,1,4- 10.

2 Tian Chao, Utilization Prospect of Carbon Dioxide and Big Nitrogen Fertilizer, 2002, Vol.25, No.3..

3 Liu Wenzong, Resource Utilization of Carbon Dioxide, Scientific Development 2007,5,465,438+03.

4 Shen, the use of carbon dioxide in chemical industry, seminar on carbon dioxide emission reduction control technology and resource utilization, September 2008

5 Liang, application and market investigation of carbon dioxide abroad, low temperature and special gas, 1997, 1.

6 Chen Jian et al., Analysis of the current situation of global carbon emission market and its enlightenment to China, Proceedings of the annual meeting of the Chinese Society of Environmental Sciences, 20 14700.

7 Zhou Wei et al., Carbon Emission in China: International Comparison and Emission Reduction Strategy, Resource Science, Vol.32, 20 10 August.

8 Zhu, development of clean coal utilization technology with zero carbon emission, the sixth energy scientists forum, Dalian, 20 15.8.