I. Development of new fuel cells
Fuel cells use gaseous fuels (such as hydrogen and methane). ) directly reacts with oxygen to generate electricity, with high efficiency and little pollution, which is a promising way of energy utilization. Traditional fuel cells use hydrogen as fuel, which is difficult to prepare and store, resulting in high cost of fuel cells. Researchers at the University of Pennsylvania in the United States have designed a new fuel cell that uses hydrocarbons such as methane, and its cost is much lower than that of traditional fuel cells that use hydrogen as fuel. Researchers have tried to use cheap hydrocarbons as fuel, but the "residue" of chemical reaction can easily accumulate on the anode of nickel battery, leading to an open circuit. The mixture of copper and ceramics was used to make the battery positive electrode, which solved the problem of "residue" accumulation. The newly developed fuel cell can use methane, ethane, toluene, butene and butane as fuel sources, and can produce methane and other hydrocarbons through microbial fermentation, which has become a rich and extensive source of raw materials for developing new fuel cells. At present, the energy conversion efficiency of this new fuel cell is still low, which needs further research and improvement.
Second, develop dual-use bioenergy.
Most military weapons, such as mobile equipment and civilian vehicles, are fueled by gasoline and diesel, and hydrogen is more ideal. Its characteristics are: (1) clean and not polluting the environment; (2) High thermal efficiency, about 3 times that of gasoline; (3) Bio-hydrogen production has potential. Because of this, it will be promising to make full use of biotechnology to produce hydrogen. If Rhodopseudomonas is used as producing bacteria and starch is used as raw material to produce hydrogen, good results can be achieved, and hydrogen can be produced 1 ml per consumption of 1 g starch. Mixing hydrogen with a small amount of other fuels can replace gasoline and diesel. Ethanol is also a clean biofuel, which has a wide range of uses and can be used to replace gasoline and diesel. The "engineering yeast" constructed by genetic technology in Japan, Canada and other countries uses its high-yield enzyme activity to hydrolyze cellulose to produce ethanol; There is also an "engineering Escherichia coli" that can effectively convert glucose into ethanol; This kind of ethanol can be used instead of gasoline or diesel, providing a large amount of biofuel for mobile devices at any time. In fact, not only bacteria or "engineering bacteria", but also some algae or other microorganisms can produce hydrogen or ethanol. Researchers such as the University of California found that a green algae (eukaryote) named Chlamydomonasreinhadtii has the ability to continuously produce a large amount of hydrogen. The key is to control the growth environment and remove sulfur from the growth nutrient solution. In this case, algae stop photosynthesis and do not produce oxygen. Under anaerobic conditions, algae must produce the energy needed for ATP by other means, and use the stored energy to achieve its ultimate goal of hydrogen production. Generally speaking, this natural algae produces very little hydrogen. Therefore, on the one hand, it is necessary to control the necessary or key factors that hinder its growth; On the other hand, molecular genetic technology is used to transform the characteristics of algae and improve its hydrogen production capacity. It can be seen that it is potential to make full use of all kinds of organisms to develop clean bioenergy for both military and civilian use.
Microcystis is the cheapest way to obtain hydrogen energy.
The ways of hydrogen production by green algae and microorganisms have been mentioned above, and the prospect of hydrogen production by microalgae is emphatically introduced here. Scientists predict that hydrogen may be an ideal energy source when oil and natural gas are exhausted. The key is to find a cheap hydrogen production method. Some experts believe that it may be the most practical choice to use the hydrogen production capacity of green algae in ordinary ponds-economical, practical and widely distributed. Green algae is a kind of miniature lower plants, which proliferates rapidly and is distributed all over the world. It has the ability to produce hydrogen under the conditions of water and sunlight. Under artificial control, green algae can be forced to produce hydrogen as needed. An experimental research report pointed out that 1 liter of green algae culture medium can produce 3 ml of hydrogen per hour, and the hydrogen production efficiency needs to be further improved. Pay attention to two points: (1) Using genetic engineering technology to improve this hydrogen production system may increase the hydrogen production by more than 10 times; (2) The application of cell immobilization technology can improve the sustained hydrogen production capacity of microalgae. In Germany, Canada, Japan and other countries, in order to realize the development plan of "clean hydrogen energy", we have actively established "hydrogen-producing algae farms" and strived to realize the large-scale production of hydrogen energy. Canada has built a factory to produce 10 tons of liquid hydrogen every day; In Japan, efficient hydrogen production by hydrogen-producing algae and photosynthetic bacteria is the research focus, and "grease hydrogen" similar to sorbet will be developed for rocket engines to improve rocket launch thrust. The United States is expected to use hydrogen energy as the main energy source in the United States by 2030. It seems that microalgae and photosynthetic microorganisms will have great development potential to produce hydrogen energy.
Fourth, make full use of organic garbage or organic wastewater as raw materials to produce hydrogen energy.
Researchers at Beili University in Japan have achieved good results in producing hydrogen with high yield from domestic garbage. Hydrogen can not only be directly used as clean energy, but also provide high-quality raw materials for the development of fuel cells, which is more economical and practical and has potential development advantages. The researchers selected an anaerobic bacterium, namely Clostridium sp. AM2 1B, and mixed it with domestic garbage such as leftovers and fish bones ground with water, and fermented it at 37℃ to produce hydrogen. The experimental results show that 49 liters of hydrogen can be obtained per 65438±0kg of domestic waste. After hydrogen production, the remaining domestic garbage is pasty and tasteless, which can be further recycled to make organic fertilizer such as compost. It is said that Japanese researchers have developed a new type of "fermentation equipment" to recycle domestic garbage for hydrogen production, which is more conducive to improving the effectiveness of hydrogen production from domestic garbage. The researchers of Harbin Jianzhu University in China established the technology of producing hydrogen from organic wastewater by microbial fermentation with anaerobic activated sludge as raw material. There are several characteristics: (1) fermentation does not use pure strains; (2) continuous hydrogen production without cell immobilization technology; (3) The process of hydrogen production system is stable; (4) the obtained hydrogen has high purity; (5) The output of hydrogen production is dozens of times higher than that of similar small experiments abroad. At present, it has entered the pilot scale of continuous hydrogen production, with a capacity of 5.7 cubic meters/cubic meter and a purity of 99%. It is expected to enter industrial production and provide a feasible biological way for the development of hydrogen energy.
5. Develop new energy with carbon dioxide waste gas as raw material.
CO2 has a wide range of sources, which is not only one of the important greenhouse gases, but also a chemical raw material. When the release and absorption of CO2 do not reach a dynamic balance, it will inevitably have adverse consequences on the ecological environment. Therefore, it is of great significance to study how to further transform CO2, a waste gas, and realize resource utilization. Among them, the realization of energy utilization is a research topic worthy of attention. At least chemical and biological methods can be used to convert CO2 into energy.
(1) catalyst used by chemical method: zeolite is used as an efficient catalyst, and about 99% of active aluminum particles adsorb rhodium and manganese. According to the ratio of CO2 to oxygen at 1: 4,300℃ and1atmospheric pressure, at least 90% of CO2 can be converted into methane, and the conversion rate can reach1atmospheric pressure. Of course, there is also a problem of reducing the cost of hydrogen and rhodium. The obtained methane not only provides energy and chemical raw materials, but also reduces the greenhouse effect including CO2.
(2) Biological utilization of algae: As mentioned above, algae, especially those micro-unicellular algae, whether prokaryotic or eukaryotic, are the most effective ways to absorb CO2 for photosynthesis and generate green new energy. A large number of microalgae make full use of CO2 in the process of proliferation, and synthesize organic matter to store solar energy under light conditions. The biomass of microalgae can be called a huge "energy storage pool". Therefore, it is feasible to make it into solid fuel or dry fuel, which can be used for power generation in Britain. It can also be used to produce methane and other energy sources by fermenting biomass of various algae (including algae). It is also desirable to continuously produce hydrogen by immobilized microalgae cells. It is precisely because of the specific functions of various algae that they are both "energy storage" and "energy supply" to obtain the required clean energy. Therefore, some experts predict that using carbon dioxide to produce bioenergy, especially hydrogen energy, will be a promising ideal energy supply in this century.
The production of ethanol by microbial fermentation is promising.
Ethanol, commonly known as alcohol, is not only used in medicine and chemical industry, but also a pollution-free clean energy to be developed in the future and one of the important renewable energy sources. It has the characteristics of complete fuel, high efficiency and no pollution. The "ethanol gasoline" prepared by diluting gasoline with it can replace leaded gasoline, and its efficacy can be improved by about 15%. It is reported that Brazil has modified hundreds of thousands of cars that use ethanol, gasoline or alcohol as fuel, greatly reducing air pollution. Since ethanol has shown its superiority in automobile fuel, how to produce ethanol in the best way? Among them, the most economical and practical ethanol production method deserves serious consideration in two aspects: one is to produce fuel ethanol from abandoned agricultural straw; The second is to cultivate green algae to produce ethanol. As far as the former is concerned, straw is a kind of crop waste with a large amount and a wide range in the world. China produces 650 million tons of straw every year, which is directly burned to pollute the environment. If even a part of these straws is used to produce fuel ethanol, it will benefit the country and the people and protect the ecological environment. If ethanol is used as gasoline additive to replace the existing leaded gasoline additive-methyl tert-butyl ether (MTBE), it will be very beneficial to improve the use efficiency of gasoline and protect the ecological environment, and it has great commercial potential. Two years ago, the amount of ethanol used as fuel in the United States reached 465,438+3,000-58,600 tons, accounting for about 83%-87% of ethanol consumption in the United States; At present, the production and market of fuel ethanol in China are blank. However, ethanol has its advantages as an effective oxygen-containing additive in gasoline. In the United States, 8% of oxygenated gasoline is ethanol, but now the only substitute for MTBE is ethanol. It is reported that at least 65,438+00,000 groundwater in California is polluted by leaked MTBE, and 65,438+04% drinking water wells in the United States are polluted. MTBE is a carcinogen of animals, which is potentially harmful to human health. On the one hand, the government prohibits the use of MTBE additives in gasoline; On the other hand, actively develop the production of ethanol as its substitute. A state in California needs 35,000 barrels of ethanol every day in the next two years (note: US 1 barrel = 3 1.5 gallon), and the demand will be 95,000 barrels in five years. To this end, American ethanol producers have been expanding ethanol production capacity; Undoubtedly, the prohibition of MTBE has brought unlimited business opportunities to the ethanol industry. It can also be seen that it is necessary to seize the business opportunity of developing fuel ethanol and develop green new energy. In China, it is completely possible to make full use of all kinds of waste straw to realize resource utilization or energy utilization in terms of conditions, capabilities and technology. As long as 654.38 billion tons of straw is used to produce fuel ethanol every year, the ethanol output can reach 20 million tons. According to the economic evaluation of relevant experts, it is considered that the cost of producing ethanol from straw is lower than that from grain fermentation. It is higher than the cost of producing gasoline in refineries, but more competitive than MTBE, a gasoline additive. Although using straw to produce fuel ethanol has certain characteristics and advantages, its production technology and effectiveness need to be further explored. As for the production of ethanol by green algae, it is very different from the traditional microbial ethanol production route. Green algae is an autotrophic eukaryote, in which Chlorella unicellular has great potential to develop new energy sources. The research team of a Japanese company obtained a new algae species from surface seawater, named TIT- 1, which is similar to Chlorella (about 10μm in diameter). Like ordinary plants, TIT- 1 can convert CO2 into starch for storage during the day and starch into ethanol under weak light or anaerobic conditions. It has its own characteristics: it will not cause environmental pollution, and it can absorb CO2 in the atmosphere, greatly reducing the greenhouse effect. Moreover, the organic combination of autotrophic and heterotrophic ethanol production is a typical example with unique advantages.
In a word, the six aspects mentioned above, no matter what form they get from different fuels or energy sources, are called "green energy". As a clean biofuel or bioenergy that does not pollute the environment, it is the development direction of energy construction in the future. The progress of modern civilization and the survival and development of human beings urgently need clean new energy and pollution-free ecological environment, which are closely related. It can be predicted that in the 2 1 century, with the needs of various constructions and the progress of science and technology, green energy will be further developed.