The hottest photovoltaic power generation adopts a

2022-08-19
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Photovoltaic power generation adopts advanced technologies such as cold hydrogenation to remove the "two high" cap

"high energy consumption and high emissions" has always been a topic that puzzles the photovoltaic industry. "It consumes China's resources and energy, and the green power produced is exported abroad, but the pollution is left at home." Until today, many people still question the development of photovoltaic manufacturing industry from this point of view. Research institutions have calculated and analyzed the energy consumption and emissions of various links in the photovoltaic industry chain. Among them, the manufacturing of high-purity polysilicon is the "major" energy consumption and emissions in the industry chain, so it is also criticized most

is the photovoltaic industry "high energy consumption and high emissions"? This has become one of the questions that the research team most wants to understand in this research interview

whether it has "two high" characteristics

"the photovoltaic industry itself is not a high energy consumption and high emission industry." Li Junfeng said

is photovoltaic power generation high energy consumption? Just calculate it. Jianglimin, chief engineer of Jiangsu Zhongneng Silicon Technology Development Co., Ltd. under poly GCL, believes that before calculating the energy consumption of the photovoltaic industry, we should first understand the uniqueness of photovoltaic products. Photovoltaic industry produces solar cell power generation system, which is different from electrolytic aluminum and other industries. It can continuously generate electricity in the next 25 to 30 years without additional energy consumption. Therefore, the energy consumption calculation of photovoltaic industry should include this part

in the research, we have seen that someone calculated the energy balance of the whole life of photovoltaic cells according to the technical level of domestic photovoltaic enterprises in 2009. Starting from raw silica sand to making crystalline silicon photovoltaic power generation system, the total energy consumption of the photovoltaic manufacturing industry chain is 2.597 kwh/watt, and the equivalent standard coal is 888.2 G standard coal/watt. Based on the annual power generation of 1.5 kwh per watt of crystalline silicon solar cells in China, the average power generation of crystalline silicon solar cells can reach 45 kwh within the battery life. The average energy consumption of photovoltaic power generation is converted into 19.73 grams of standard coal/kWh by combining the energy consumption of manufacturing with the power generation. In 2009, the national average coal consumption for power generation was 342 grams of standard coal/kWh, and the energy consumption of photovoltaic power generation was only 1/17 of that of coal power. Moreover, with the development of technology, this energy consumption is still decreasing

in terms of emissions, silicon tetrachloride is the most difficult substance to deal with in the by-products of polysilicon production, but the emission problem of this substance has been solved according to the polysilicon production process designed in a closed cycle

in the polysilicon material production plants of LDK and China energy silicon, we can see a closed-loop system of material circulation and energy recovery and utilization formed by dense pipelines. Taking the GCL process technology with independent intellectual property rights improved, upgraded and formed by Zhongneng silicon on the basis of the traditional improved Siemens (Weibo) process as an example, polycrystalline silicon production takes metal silicon as raw material, reacts with silicon tetrachloride, hydrogen and hydrogen chloride to synthesize trichlorosilane, and after rectification, purification and vaporization, trichlorosilane is reduced with high-purity hydrogen at high temperature to obtain polycrystalline silicon products. Trichlorosilane and hydrogen, as well as silicon tetrachloride and hydrogen chloride gas as by-products, which are not reacted during the reduction process, are separated by a dry recovery system, in which the mixed liquid of silicon tetrachloride and silicon trichloride is sent to distillation for purification. Based on the consideration of safety problems caused by the easy crushing of glass beer bottles, we actively explore the use of green financial means such as green bonds and green insurance to get high-purity silicon trichloride and send it back to reduction to produce polysilicon, Silicon tetrachloride is sent to the chlorination hydrogenation synthesis system to convert into trichlorosilane, which is purified and then returned to the reduction system for use; The separated and purified hydrogen is returned to the reduction process to produce polysilicon, and the hydrogen chloride gas is sent to the chlorination synthesis process to completely realize closed-circuit circulation and clean production

in the research, Zhu Bing, the chief financial officer of LDK silicon Chemical Technology Co., Ltd., mentioned an interesting phenomenon: China photovoltaic industry alliance made a statistics at the end of April this year and found that major foreign polysilicon manufacturing enterprises have high enthusiasm for expanding production. OCI of South Korea, Wacker of Germany and hemlock of the United States have the largest expansion pace. It is expected that the production capacity of these three enterprises will exceed 50000 tons by the end of this year, It will reach 62000 tons respectively. This year, the overall import of extruders will decline significantly, 52000 tons and 50000 tons. However, none of these bustling expansion plans chose China as the site

according to the data, up to now, none of the seven traditional polysilicon companies in the world has built factories in China or transferred technology to foreign countries. Questions also arise. If polysilicon production is "high energy consumption and high emissions", why have the United States, Japan and Germany kept polysilicon production in their own countries? Why has the technology been blocked

the former hat of "two forming temperatures: 290 (3) 50 ℃ high"

since the photovoltaic industry does not belong to the industry of "high energy consumption and high emissions", how does this "hat" wear

"in the early stage of polysilicon production development, the technical level of equipment, process and other aspects is not high, and the energy consumption value calculated on this basis is relatively high." Zhu Bing analyzed that in previous years, it was estimated that polysilicon production consumed 400 kwh per kilogram. This data was calculated based on the technical level of a nine pair rod reduction furnace growing for 15 days and producing 50 kg per furnace. In a reduction workshop of LDK, there is a production record on May 18, 2011. There are 24 pairs of rods in this reduction furnace. The growth time of one furnace is 85 hours, and the unit power consumption is only 56.65 kwh/kg

in addition to the technical level, the view that the "high energy consumption and high emissions" of the photovoltaic industry is not entirely elusive. The market price of polysilicon was still about $20 per kilogram in 2004, but in the next few years, with the rapid development of the photovoltaic industry, the price of polysilicon soared, once climbing to a high of nearly $500 per kilogram. High profits drive capital to enter this industry crazily. When there is no complete process and technical conditions, investors just want to start the project as soon as possible and produce silicon materials to sell as soon as possible. It is inevitable that the energy consumption is high and the environmental protection design is not careful enough. It is this regardless of cost that caused many enterprises to have problems in energy consumption and emissions at that time, and also left the impression that photovoltaic power generation is not clean energy

now it is not what it used to be.

"the polysilicon industry is now a different scene." Jiang Limin said that people's understanding of the polysilicon industry needs to be updated. Zhongneng silicon is the most important silicon material production enterprise under poly GCL. In mid May, we walked into the Zhongneng silicon plant in Xuzhou, Jiangsu Province, and saw the green grass here, the beautiful flowers, and the outer walls of the buildings are dark red. This is not like a chemical plant, but more like a research and development organization

"compared with previous years, the energy consumption index of polysilicon production has decreased a lot." Jiang Limin said that the energy consumption of polysilicon production by leading domestic enterprises has been reduced from 200 kwh/kg two years ago to 80~150 kwh/kg

for the entire photovoltaic cell industry chain, the research team calculated an energy consumption account: in 2011, China's newly installed photovoltaic capacity was 2.2gw. According to the current production of about 2 kwh of solar cells per watt, the installed solar cells in China consumed a total of 4.4 billion kwh in the manufacturing sector in 2011; According to the average annual utilization hours of China's photovoltaic power generation system of 1200 hours, the annual power generation capacity of these 2.2gw photovoltaic cells is about 2.6 billion kwh, and the two-year power generation capacity is enough to repay the power consumption in the production process. If in the 25 year life cycle, this 2.2gw will generate about 66billion kwh of electricity

the emission of polysilicon production is more than yesterday's appearance. In front of the huge sand table in the plant, Jiang Limin specially introduced the hydrochlorination technology in the hydrogenation link of Zhongneng silicon industry, "the application of the improved new hydrochlorination technology has once again reduced the energy consumption and raw material consumption, reduced the manufacturing cost, and made another big step in the capacity of a single device for processing silicon tetrachloride". Silicon tetrachloride is the main by-product of polysilicon produced by the improved Siemens method. For each ton of polysilicon produced, 12 to 18 tons of silicon tetrachloride will be produced. It is a dangerous chemical that releases corrosive gas HCl when wet, and generates hydrochloric acid when excessive water. Unlike trichlorosilane, it is not flammable and explosive. The polysilicon industry was once mistaken for a high emission and high pollution industry, and the main problem lies in it. Only through hydrogenation, it can be converted into silicon trichloride and become the raw material of polysilicon production again, can this by-product be properly handled, while realizing resource recycling and improving efficiency

"advanced technologies such as cold hydrogenation make polysilicon production form a complete closed-circuit circulation system, which not only helps enterprises solve the problems of energy consumption and environmental protection, but also keeps enterprises away from high energy consumption and high emissions. More importantly, it helps enterprises solve the problem of high costs, which is a matter of life and death for enterprises facing severe market situation." Jiang Limin said that after bidding farewell to the era of huge profits, when prices plummeted to a rational range, controlling costs and improving efficiency became the key to survival. Polysilicon production enterprises that could not reduce energy consumption and achieve closed-loop production simply had no place in today's market

the changes of emerging industries are changing with each passing day, and people's eyes on them must keep pace with the times. Polysilicon production, which once went through a detour, has been transformed, and the technological development of the photovoltaic industry has changed. After experiencing these changes, I found that I have the latest understanding of this industry. However, it is not too much to tighten the strings of safety and environmental protection at any time. Zhonghua glass () Department

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