In rural areas, crop straw is used as an energy source for cooking, boiling water and heating. Straw direct combustion not only wastes straw and is not hygienic, but also causes environmental pollution. Some farmers burn straw in the earth, which not only wastes resources, pollutes the environment, but sometimes affects the normal take-off and landing of the aircraft. Faced with the contradiction between oil supply and demand and the depletion of conventional energy sources and the unscientific utilization of straw, we should develop and use renewable energy to study the scientific methods of using straw to solve the problems caused by insufficient energy and large quantities of straw. Black Dried Goji Berries,Organic Black Dried Goji Berries,Wholesale Black Dried Goji Berries,Black Goji Berry Ningxia ZhaiXianSong Commercial and Trading Co.,Ltd. , http://www.nxupin.com
Over the years, people have conducted a lot of research on the use of corn and straw as renewable energy sources, and successfully explored new equipment, new technologies, and new models for the use of corn and straw as renewable energy sources. Practice has proved that corn is not only a food crop and an economic crop, but also a renewable energy crop.
1 Development and Utilization of Corn as a Renewable Energy Source
In the 1970s, when the oil crisis occurred in the world, the Brazilian government formulated a plan to use alcohol as a fuel instead of gasoline in order to develop agriculture and solve the energy crisis. Through a lot of experiments and research, alcohol has been successfully applied to automobiles and is the first country in the world that does not supply gasoline. According to reports, Brazil now has 15.5 million cars, 3.5 million motorcycles use ethanol gasoline, and 2.2 million cars use water-based alcohol as fuel. According to reports, more than 20 countries have promoted the use of ethanol gasoline in the world.
Since 1999, China has begun to study the production of fuel ethanol from corn.
1.1 Production of Fuel Ethanol from Corn as Fermentation Material
1.1.1 The production of fuel ethanol. Ethanol production from corn is a kind of bio-transformed solar energy and it is an inexhaustible renewable energy source. Ethanol can be produced through fermentation, distillation and other processes using corn as a raw material. During the production of ethanol, by-products such as protein feeds, carbon dioxide, corn oil, and distillers' grains can also be obtained. About 3.3 tons of corn are needed to produce 1 l of ethanol. In 2001, China’s largest corn-based ethanol manufacturing project began in Jilin City, Jilin Province. In 2003, the Jilin Fuel Plant was put into production and produced 300,000 tons of ethanol annually. The plant plans to increase production to 600,000 t2J in the future.
1.1.2 The promotion and application of ethanol gasoline. Ethanol gasoline is a mixture of ethanol and gasoline in a certain proportion. Because there are certain differences in fuel performance between ethanol and gasoline, there are two methods for using ethanol gasoline. One is the application of the original gasoline engine, that is, no change to the original gasoline engine. When using the original gasoline engine, the amount of ethanol added should be controlled. In general, the amount of ethanol added is controlled at 5% to 22%. The other type is a dedicated engine. The so-called dedicated engine is an engine specially developed for the use of ethanol gasoline. The amount of ethanol added to a dedicated engine is 85% to 100%.
At present, China's promotion of the application of ethanol gasoline is the application of the original gasoline engine, the amount of ethanol added is 10%, this will not affect the original gasoline engine fuel consumption and power. In 2003, the use of ethanol gasoline was piloted in Jilin Province. In 2004, eight ministries and commissions including the National Development and Reform Commission jointly issued the “Expanded Pilot Program for Ethanol Gasoline for Vehiclesâ€. Heilongjiang, Jilin, Liaoning, Henan and Anhui provinces promote the use of ethanol gasoline in the province. At present, the market coverage of ethanol gasoline for motor vehicles in Jilin Province is close to 90%. In 2011, the sales volume of ethanol for gasoline reached 800,000 tons. The coverage rates in Liaoning, Heilongjiang, and Henan provinces reached an average of over 80%. Hebei, Shandong, Jiangsu, and Hubei provinces have promoted the use of ethanol gasoline in some regions. Now China's provinces that promote the use of ethanol gasoline have reached nine.
1.1.3 The significance of promoting the use of ethanol gasoline.
(1) Ethanol as an energy source can replace petroleum. At present, China consumes 40 million tons of gasoline each year. If all 10% of ethanol is added, 4 million tons of ethanol will be needed, and 4 million tons of ethanol will replace 4 million tons of gasoline. It is estimated that the production of lt gasoline requires 5.7 tons of crude oil, then 4 million tons of ethanol can replace 5.7400 = 22.8 million tons of crude oil, almost to the production of Shengli Oilfield.
(2) It helps to protect the environment. Ethanol is a gasoline quality improver and green oxygen enhancer. The addition of ethanol to gasoline can completely replace the MTBE (methyl tertiary butyl ether) oxygen additive in regular gasoline. Because MTBE has a detrimental effect on groundwater resources, adding ethanol to gasoline instead of MTBE can reduce groundwater pollution. Adding 10% fuel ethanol to gasoline can increase the octane number of gasoline by 3% and the oxygen content by 3.5%, which improves the performance of gasoline, makes gasoline more complete and thorough, and can reduce and eliminate vehicle exhaust. The formation of smoke. According to a report by the Environmental Protection Bureau of Jilin Province on the tracking and testing of car tail gas using ethanol gasoline in 9 cities in the province, the average concentration of carbon monoxide in car exhaust gas using ethanol gasoline has fallen by 11% compared with that of cars using regular gasoline. The average concentration dropped by 9.6%.
(3) It is conducive to grain transformation and promotes farmers to increase production and income. The long-term storage of corn caused the Aspergillus flavus to exceed the standard and could not be eaten. The use of aged grain corn as raw material for the production of ethanol, so that the grain of corn into energy conversion. The central and western regions of Jilin Province are golden corn belts and are rich in corn. It is often the case that farmers do not increase their output, and it is difficult to sell grain (corn). Ethanol production from corn can consume large amounts of corn. Assuming that 4 million tons of ethanol are produced each year, 13.2 million tons of corn can be consumed. In this way, the production of ethanol from corn can save conventional energy, and can also solve the problem of aging grain conversion, and at the same time solve the problem of farmers selling grain (corn). According to statistics from the Office of Ethanol Gasoline Promotion of Jilin Province and Heilongjiang Province, since September 2004, about two million vehicles in two provinces have used ethanol fuel to fuel the local economy by 5 percentage points, and the per capita income of farmers has increased by 56 yuan.
1.2 Production of biogas from anaerobic fermentation raw materials using corn alcohol distillates The corn alcohol distillates are wastes produced from corn as raw materials. The production of lf ethanol produced approximately 12.15 m3 of waste liquid. The content of COD, BOD, SS in corn dregs is extremely high, the water temperature is high, and the pH is acidic. Corn alcohol dregs is a good raw material for biogas fermentation. The corn alcohol dregs is anaerobicly fermented by a large-scale biogas fermentation device to produce biogas. The biogas produced can be transported directly to the user as a fuel through a gas pipeline. According to reports, Nanyang Tianguan Group of Henan Province produces 100,000 tons of alcohol per year, with a daily production of 50,000 m3 of biogas, which can supply 40,000 households with gas.
2 Development and Utilization of Corn Stalks as Renewable Energy
2.1 Gasification of corn straw Gasification In recent years, China has done a lot of research on straw thermal decomposition gasification technology and straw gasification equipment. The self-developed gasification technology of straw gasification is at the leading position in the world. For example, the XFF-type biogasification unit and the supporting technology of the centralized gas supply system and the user gas system have entered the stage of commercialization and have been listed as "Spark" demonstration projects, which are well received by farmers. According to reports, the straw power generation project was signed in Qingdao. The project is invested by Canadian Rexwell Group Renewable Energy Co., Ltd. It adopts international advanced thermal decomposition technology to process 800 tons of straw per day with an installed capacity of 36,000 kW.
2.1.1 straw gasification principle. Corn stalk, corn kernel, etc. are used as raw materials. After pulverization, the pyrolysis, oxidation and reduction reactions of the gasification equipment are converted into combustible gases. Straw incomplete combustion in the gasifier is the process of heating the reaction in the absence of oxygen. During this process, carbon and hydrogen become carbon monoxide, hydrogen, methane and other combustible gases.
When the water content of corn stalks and corn kernels does not exceed 20%, lkg corn stalks and corn kernels can produce 2m3 of combustible gas. According to inspections by relevant departments, under normal circumstances, the company's fuel gas contains CO11% to 20%, H, 10% to 16%, CH40.5% to 5%, C0210% to 14%, 02 less than l%, and a small amount of sulfur Hydrogen, tar and dust. The combustible gas has a combustion value of 4000 to 5000 kJ/m3.
2.1.2 Benefits.
1 Straw gas can replace conventional energy sources. According to lrn3 straw gas instead of 0.25l (g standard coal, a household of 4 households uses 6m3 of straw gas per day, each household uses straw gas of 2190m3 per year, each household uses straw gas to replace 548kg of standard coal per year.
2 Significant environmental benefits. According to lt straw instead of 0.7t coal, 10,000 tons of straw can replace 7003 tons of coal. Then, 10,000 tons of straw can reduce CO2 emissions by 14,000 tons, SO2 emissions by 140 tons, and soot emissions by 100 tons. For rural families, the use of straw gas is much cleaner than direct burning of straw.
3 Reduce labor intensity and reduce cooking time. The use of straw gas in comparison with direct burning of straw can reduce the labor intensity of household women, and can also reduce the time for cooking 1.5 ~ 2h/d.
2.2 Production of biogas from anaerobic fermentation raw materials using corn stalks Biogas is produced from anaerobic fermentation raw materials using straw as a raw material, which has been popularized in the south of China for many years. The use of straw to take biogas commonly used special biogas digesters. The corn stalks are cut into 3 to 5 cm long, and they are stacked around the pond for 7 days before entering the digester. Then the biogas can be produced by adding anaerobic fermentation to the corn stalks and manure in accordance with a certain proportion. The fermentation concentration is generally controlled at about 25%, the fermentation period is 2 to 3 months, and the average pool capacity is 0.4 m3/(m3d). The biogas produced is transported to the user as a fuel through a gas pipeline. According to reports, lt corn stalks can produce about 1130m3 of biogas, and 1m3 of biogas has a calorific value of 20900~22990kJ, equivalent to 0.76t of standard coal. Biogas production can also obtain by-products of biogas residue and biogas slurry. Biogas residue can be used to feed pigs, fish, etc. Biogas fertilizer can be used as organic fertilizer and soil improver, and biogas slurry can be used for soaking seeds.
2.3 The corn stalks are passed into the biogas digester and then used to produce biogas. The corn stalks are good livestock feed. Corn stalks contain more than 30% carbohydrates, 2% to 4% protein, and 0.5% to 1% fat. Under normal circumstances, corn stalks can be directly digested and used by herbivores, but after corn stalks are processed through silage, yellow storage, ammoniation, etc., they can improve nutrition, increase the taste of livestock, and improve utilization. Cow manure can be used as anaerobic fermentation feedstock to produce biogas. According to reports, the city of Liaocheng has established more than 800,000 m3 of silo, 600,000 tons of silage, 110,000 cattle, 1.57 million m3 of biogas, and 6,262 users of biogas.
2.4 The production of fuel ethanol from corn stalks as raw materials Experts pointed out that at present, the country's rural areas can produce 700 million tons of straw each year, which can be converted into 100 million tons of alcohol, equivalent to three Daqing oil fields. There are about 150 million tons of corn stalks in China each year. Therefore, the use of corn stalks to produce fuel ethanol has good prospects. However, at present, we must do a lot of research work technically.
3 Utilization patterns of corn and straw as renewable energy sources In summary, we have summarized the utilization patterns of corn and straw as renewable energy sources.
4 suggestions
(1) Every effort should be made to increase the yield of corn. Judging from China's corn production, only about 10 million tons of corn can be used to produce fuel ethanol each year. This is a lot different from the fact that China's 2004 imports of crude oil reached 1.227.2 billion tons. Therefore, a dedicated corn (corn for fuel ethanol production) production area should be designated, and a number of technologies such as genetic modification should be used to increase the yield and total yield of corn.
(2) It is necessary to increase research efforts in the production of fuel ethanol from straw. China's straw production is very high. If straw can be used to produce fuel ethanol, its benefits are considerable.
(3) Study dedicated engines. The dedicated engine mentioned here refers to an engine that uses exclusively ethanol gasoline. With the popularization and application of fuel ethanol, the amount of ethanol added to gasoline will gradually increase, and the original gasoline engine will no longer be suitable. Therefore, new dedicated engines must be studied.