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Identification of the self-produced steam-equilibrium nitric acid device localization
expert panel for the first double pressurization method
The 8th domestically produced 100,000-tonne double-pressurization nitric acid plant was successfully ignited and charged on September 16, 2007 at Henan Xinxiang Yongchang Chemical Co., Ltd., and it was fully loaded on September 22. It is understood that this is also the first domestically produced double-pressurizing steam-balanced nitric acid plant. The previous seven units cannot achieve by-product steam self-sufficiency at full-load production.
On November 8th, the expert team appraised the device that had been running for nearly two months and concluded that the daily output of nitric acid was more than 350 tons (100% nitric acid); under the full load condition, the by-product steam could not only fully satisfy self-use, but also It can export about 1 ton/hour; when the equipment is under 70%～105% load operation, the finished acid concentration is ≥61%, while the exhaust gas emission nitrogen oxide concentration is less than or equal to 180ppm, the exhaust gas can not see yellow smoke; ammonia consumption, oxidation rate The core technical indicators such as absorption rate and absorption rate all reached the level of imported devices (see Table 1). The overall level of technology has reached the technological level of similar devices abroad, and the operating status of domestically-built “four-in-one†units has also basically reached the same level as foreign devices. The successful commissioning of the device indicates that the domestic double-pressurization nitric acid device has solved the technical problems of self-produced steam under-charging, exhaust gas failure, high ammonia consumption, and low finished acid concentration under full-load operation. The design of pressure nitric acid equipment, localization of equipment, and process control and production management have reached a new level.
It can be seen that when the device is operating at full load, the core technical and economic indicators of the process have reached and slightly exceeded the level of foreign technology. Although the amount of steam delivered is not as advanced as abroad, it has been resolved that the domestic nitric acid device has been operating at full capacity in the past. Under the conditions of the byproducts of steam production problems, the main power consumption - steam fully self-sufficient system, and a little surplus outside the transmission. This is another important milestone following the complete localization of the nitric acid plant in China, and the level of process driving and various technical indicators are completely in line with the international advanced level. It is a national nitric acid production process that catches up with international standards, saves money, reduces energy consumption, and reduces pollution. Made important contributions.
The long history of localization
Although the "steam balance" technology fortress was eventually conquered on the 8th domestically produced device, before this time, China's major chemical research institutes were able to surpass the international advanced level on the road for long-term travel and success. In a sense, there can be no second-generation or third-generation without the domestically produced dual-pressure first-generation technology; without the first domestically-made double-pressurization device in 1999, there would be no 8 sets.
The industrial production of nitric acid in China began in 1935, when the country’s production capacity was only 1200 tons/year. In the early days after the founding of the People's Republic of China, nitric acid was used as a military third-line product that was used in combination with ammonium nitrate. For consideration of secrecy and concealment, most of the devices were built in mountainous and remote large- and medium-scale fertilizer plants. The scale was small, the technology was backward, and the pollution was serious. Because they are located in remote areas, after entering the market economy, the survival and development of these enterprises have encountered great difficulties. Even at the time when the relatively large-scale 80,000-ton-scale devices were produced, their technological equipment was at an international level. The ratio is also quite backward.
Since the 1980s, the development of the domestic nitric acid industry has begun to accelerate, and the total output has increased by 10% to 15% annually. Especially in the late 1990s, the nitric acid industry in China entered a period of vigorous development, and the annual growth rate of total production reached 15% to 20%. However, in this period, the production technology of nitric acid in China was still relatively backward. The early atmospheric pressure and comprehensive process equipment were mostly used-out production lines, and the high-pressure method devices all depended on foreign used imported equipment. At the same time, the more advanced double-pressurized process nitric acid production technology at the time was a goal pursued by the domestic nitric acid production industry due to its high total output, large stand-alone scale, low energy consumption, and superior pollution emission standards. As the core equipment of the double pressurization nitric acid plant, the "four-in-one" unit consisting of a steam turbine, a nitrogen oxide gas compressor, an air compressor and an exhaust gas turbine accounts for about 50% of the total investment of the nitric acid plant, becoming a double pressurization. The first difficulty in the localization of French nitric acid plants.
In the early 1980s, Tianji Group (formerly Shanxi Fertilizer Plant) imported the first set of double pressurized nitric acid equipment from China (at the same time, it introduced two sets of 270,000 tons of equipment). It uses the French GP process and the German GHH. A "unit (in 2002 the plant introduced another one, a total of three sets of 270,000-ton devices). Since then, our country's nitric acid industry has gradually entered the ranks of advanced international teams in the application of technology and equipment. However, due to technical barriers, this advanced technology has been monopolized by foreign developed countries. In the following 10 years, domestic double pressurized nitric acid plants and “four-in-one†units have long depended on imports, which seriously restricted the nitric acid industry in China. Development process.
In 1999, Xi'an Shaanxi Drum Power Co., Ltd. successfully introduced the first "four-in-one" unit in China through the introduction of compressor design technology and machine set technology from Swiss SULZER, and applied it to Yunnan Yunfeng Chemical Industry Co., Ltd. from then on. It opened the prelude to the domestic advanced equipment of China's nitric acid dual pressure process to the international advanced level. Yunnan Yunfeng Chemical Industry Co., Ltd. as the first nitric acid production enterprise to use domestically-built “four-in-one†units successfully built a demonstration project for the domestic production of double-pressurization technology for the nitric acid industry in China, which confirmed the domestic nitric acid production enterprises. The confidence of choosing domestic equipment led to the subsequent second set of Shijiazhuang Fertilizer Plant, the third set of Liaoning Liaohua, the fourth set of Jiangsu Nanhua, the fifth set of Anhui Huatai, and the sixth set of Shandong Haihua. The 7th unit was jointly with Shandong, until the 8th double-pressurization process localization unit of Henan Yongchang in 2007. The relevant conditions of these 8 domestically produced devices are shown in Table 2.
During the construction and operation of these eight devices, the technicians of the China National Institute of Chemical Research and Development spent a total of eight years and re-started again and again as a result of the technical difficulties in the by-product steam balance. How difficult is this? A technology relay race!
Then, "who is the hero who overcomes the technical bottleneck of steam balance?" is Xi'an Shaanxi Drum Power Co., Ltd., a manufacturer of nitric acid unit core equipment "four-in-one" units? Or is it responsible for the installation and debugging of the device design, and the privately-owned technology company Linyi Yuanjing Chemical New Technology Co., Ltd., whose name is still unknown in the near future? Or is it a large number of engineering researchers who have invested a lot of effort in this same difficult problem, and despite continuous seven sets of devices that have not yet achieved a breakthrough but are still failing at all times? Differing opinions are difficult to make. However, perhaps this lacks any element and there will be no joy in today's success.
However, it must be emphasized that the dual pressurized nitric acid plant can eventually be fully domesticated and quickly surpass the world's advanced technological level. The performance of its core equipment, domestically produced "four-in-one" units, has played a very key role in promoting, and at the same time Continuous improvement and innovation in process design are also inseparable. The fourth set of equipment can achieve the balance of steam self-production, but it must be at the cost of reducing system pressure and load and increasing production costs, and the "four-in-one" unit has not yet been fully domesticated. Therefore, it can be said that only the 8th set of equipment can truly self-produce steam balance and have surplus capacity under the conditions that the equipment unit equipment is fully domesticated, full-load operation, and all process indicators meet the design requirements. It can be foreseen that the breakthrough of this technology will completely end the long-term situation in which imported devices will dominate the world, allowing China's nitric acid manufacturing technology and equipment to go global and compete with advanced foreign technology. The history of imported technology monopolizing the Chinese nitric acid industry is gone forever!
The results of the technical exchanges were held in Hui County, Henan Province, the “National Double Pressurization and Full High-Pressure Nitric Acid Plant on-site Technical Conference†and the “Double Pressurization Nitric Acid Production Thematic Technical Exchange Symposium†held in Taian, Shandong Province. More than one hundred representatives from research and design institutes and more than 60 companies gathered to discuss the problems existing in the operation of the localization device of the double pressurizing technology, and the corresponding solutions and suggestions. They expressed their opinions freely, expressed their sincerity and moved the atmosphere.
Mr. Xiao Cheng, the technology development department of Shaanxi Xinghua Co., Ltd., is the predecessor of the nitric acid production process and has frequently dealt with foreign technical personnel. He told reporters that Westerners do not understand Chinese family-style technical communication habits because they attach great importance to technological confidentiality, the so-called protection of patents, and the information between their domestic enterprises is absolutely incommunicable. Actually, the practical need for intellectual property protection is banished and excessive technical blockade against domestic counterparts is a kind of self-contained in a sense. It is unfavorable to the overall development of a country, but it will impede the advancement of technology. Director Xiao said that he had personally contacted an expert from abroad. He wondered how he had dealt with a Chinese company. Just a few days, Chinese companies in the entire industry knew relevant information. Director Xiao said with great pride: "This is exactly the difference between Chinese and Westerners. As long as one unit in our country has mastered the new technology of nitric acid, the entire day will be mastered by the whole Chinese nitric acid business. They will take the initiative to announce to everyone through 'exchange conferences' and 'seminars'. China’s technology does not block China’s people and it is just like this that catches up with the developed countries!â€
Delegates thanked the organizers from the bottom of their hearts for providing the information exchange platform for the nitric acid industry so that everyone can share the achievements brought by advanced technologies. The breakthrough of some technical difficulties is to a large extent also due to this kind of exchange meeting. It can be said that technical exchanges and technical discussions have effectively promoted the technological progress of the domestic nitric acid industry.
The benefits of steam balance
The solution to the "steam balance" problem of domestic double-pressurization nitric acid plants is expected to bring about incalculable economic and social benefits.
At present, domestically produced 100,000-ton-grade nitric acid complete sets of equipment cost about 40 million to 50 million yuan, which is only 45% to 50% of the price of imported equipment of the same scale. Apart from this, the steam generated by the device itself alone will not be underestimated. Take the data of the third generation domestic double pressurized nitric acid plant before the “steam balance†as an example, the production of nitric acid requires an external supplement of steam of about 2.5 to 3 tons per hour, and the 8th domestically produced unit in Hui County, Henan Province, can be out of the hour. About 1 ton of steam is transported, according to the current market price of 140 yuan for 1 ton of steam, two-phase comparisons can save 420 to 560 yuan per hour for enterprises, which is 3.6 million to 4.8 million yuan a year. This does not include The lack of self-supply of steam, the expense of constructing a set of boilers that must be invested and the environmental protection expenses required for supporting boilers do not include the comprehensive competitive advantages of the market due to cost reduction, and significant clean and environmental protection effects. For enterprises, it is a great asset.
Although
there is still a need to break through the localization of double-pressurization nitric acid plants, although it has taken a big step forward, this does not mean that we have achieved our goal. What we celebrate is only to shorten the distance from the target.
The double pressurized nitric acid process is currently the most advanced and environmentally friendly new process in the world. The 8th domestically produced 100,000 ton-class double-pressurizing nitric acid plant, although some of the major process economic and technical indicators have reached or even slightly surpassed the level of foreign countries, but there is still a certain gap between the amount of steam to be delivered abroad and this gap remains. The majority of engineering and technical personnel in the industry are required to work together to catch up. To do this, we must strive to further increase the output of medium-pressure steam produced by by-products and increase the delivery volume.
In addition, at present, the international standard for the concentration of nitrogen oxides in industrial exhaust emissions is set according to the current level of less than 200 ppm in the United States. Although China's eighth domestic double-pressurized nitric acid device has reached 180 ppm, it is the most stringent in the world. There is still a considerable gap between the 120-150ppm energy-saving emission reduction requirements and our design standards have yet to be improved.
Furthermore, domestically-built “four-in-one†units need to be further improved in increasing the recovery power of exhaust gas turbines and reducing the steam consumption of steam turbines, so that the overall performance of domestic “four-in-one†units can reach the advanced level in foreign countries as soon as possible. Only the process and the "four-in-one" unit are closely coordinated with each other, and the localized nitric acid plant is expected to further break through.
At present, developed countries have generally adopted nitric acid plants of 270,000 tons and 500,000 tons. The 100,000-tonnage process began to be phased out and transferred to developing countries 20 years ago. China's imports in recent years are currently more advanced domestically. Equipment and equipment are basically second-hand goods that are eliminated by others. Even if some of the larger nitric acid companies in China, the scale of production capacity is simply the repetition and accumulation of the original process equipment, and it is not the large scale formed by the large devices in the true sense. 270,000 tons/year double pressurization method Domestically produced nitric acid plant There are currently several domestic companies that are currently under construction, including Henan Kaifeng Jinkai Chemical Industry Co., Ltd. and Ningbo Wanhua Polyurethane Co., Ltd. 270,000 tons/year localization unit. Construction has begun.
Relevant information shows that in 2006 China's nitric acid production capacity was 6.292 million tons, ranking second in the world. The annual production capacity from 2007 to 2008 will reach approximately 7.77 million tons, surpassing the United States to rank first in the world. However, we still have a long way to go from nitric acid production to power.
The editors reported an exciting news at the “Double Pressurization and Full-Pressure Nitric Acid Plant On-Site Technical Conference†in Hui County, Xinxiang City, Henan Province in early November 2007. The domestically produced double-pressurization nitric acid plant with self-sufficient steam production and surplus steam supply under full load production conditions was born in Xinxiang Yongchang Chemical Co., Ltd. Apart from self-produced steam, the main technical indicators of the device have reached or even exceeded the current process parameters of imported devices in China. This means that in the future, if nitric acid production enterprises in China purchase nitric acid plants again, they will not need to pay extra foreign exchange to import foreign equipment or buy used foreign plants. This is because the homemade nitric acid device developed by China itself not only relates to foreign products in terms of quality and efficiency. The level is quite equivalent to being able to completely replace imports, and its price is only 50% of imported equipment. Domestic nitric acid production enterprises can finally use high-level domestic equipment to get rid of the high cost and poor service quality of imported devices. This article specifically introduces the localization of double-pressurization nitric acid devices to readers.
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