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(Chemical Planning Institute)
The medium-sized nitrogen fertilizer plant is the mother of China's nitrogen fertilizer industry. It not only provides a large amount of chemical fertilizers and chemical raw materials for industrial and agricultural production in China, but also provides technical and management experience for the development of China's chemical industry, especially the development of nitrogen fertilizer industry. It has cultivated and transported a large number of Talents have made great contributions to the development of the national economy. In 1997, China's nitrogen fertilizer industry's ammonia production capacity reached 6 million tons, accounting for 18% of the country's total capacity, urea capacity of 5.39 million tons, accounting for 24% of the country's total capacity. In addition, in recent years, the small-scale nitrogen fertilizer has developed into a medium-sized factory. There are about 100 medium-sized nitrogen fertilizer plants in the country, with a total ammonia production capacity of 10 million t/a, accounting for 26% of the national ammonia production capacity. : 000 million t / a or so, accounting for about 40% of the country's total capacity, it can be seen that the nitrogen fertilizer is the main force of China's nitrogen fertilizer industry.
Most of China's medium-sized nitrogen fertilizer plants were built in the 1950s and 1960s. The synthetic ammonia plant of coal-based medium-sized nitrogen fertilizer plant mainly adopts the self-developed process technology in China, such as atmospheric pressure fixed layer coal gasification, rubberized desulfurization, hot potash decarburization, reciprocating compression, high pressure synthesis, etc.; The aqueous solution is used in a full cycle process. The synthetic ammonia process using oil as a raw material is also developed domestically. Only some plants that use gas as raw materials use imported technology. In general, China's synthetic ammonia and urea production technologies are relatively backward, especially in some factories with coal and coke as raw materials. They were built in the 1950s and 1960s, some factories are innately inadequate, and equipment is Chen; daily, energy consumption is high, and it has been running for many years. The renovation and renovation efforts are not enough. Moreover, most of the existing medium-nitrogen enterprises are small in scale (general ammonia is 60-80,000 t/a, urea is 130,000 t/a, public utility has great potential, many people, poor competitiveness, and anti-risk The capacity is weak; in addition, the three wastes of the factory are higher than the national standards and urgently need to be reformed. During the “Eighth Five-Year Plan†and the “Ninth Five-Year Plan†period, although the state invested a part of the funds to implement technological transformation of the medium nitrogen fertilizer (such as the use of ADB, World Bank loans in There are 12 sets of 8 to 131 courses in 12 factories, and the technical transformation of more than 20 factories is mainly to increase 20,000 to 30,000 t/a of synthetic ammonia and 30,000 to 50,000 tons of urea. However, the transformation is not big enough. Under the new situation of fierce international and domestic competition, we will use the newly developed new technologies in recent years to increase the intensity of technological transformation of medium nitrogen fertilizers on the basis of existing ones, further expand the scale of equipment, reduce consumption and cost, and reduce and reduce abroad. As well as the gap between domestic large-scale nitrogen fertilizer plants, it is imperative to improve competitiveness. How to transform? I would like to put forward some ideas on this.
First, we must highlight technological progress
Most of the medium-nitrogen fertilizer enterprises adopt domestically produced process technology and equipment, and their technological transformation must also rely on domestic research, design and new technologies and technologies developed by scientific research departments such as universities and colleges.
1. Transformation of synthetic ammonia technology
(1) The gas-making gas-making furnace adopts a new type of hearth and furnace, and the gas-making is controlled and optimized by the microcomputer; the superheated steam is used to increase the steam pressure of the gas-making waste pot, and the gas-making fan is modified to increase the blowing strength. Increase the gas production of a single furnace.
(2) Desulfurization adopts spray regeneration technology and new filler technology to improve production capacity and desulfurization effect.
(3) Transforming the existing equipment to carry out all-low-variation technology transformation and adopting new catalysts.
(4) Enterprises that use pheno-Phenol decarburization technology for decarbonization can be modified by double-column pressure-variable regeneration, sterically hindered amine, steam jet flashing, etc.; enterprises using physical absorption technology can adopt low energy consumption such as NHD. The decarbonization technology is reformed; the decarbonized rich liquid is recovered by a hydraulic turbine.
(5) Refined copper washing is technically modified through new fillers, new trays, etc., and methanation uses a new type of catalyst.
(6) The synthesis is carried out by using new internal parts. For example, the IIIJ-99 type of Hunan Anzhen Company or the NC-1200 axis radial synthesis internal parts of Nan'an Company are used, and the middle waste pot recovers heat.
(7) Compression The compressor adopts the crucible tank, adds the auxiliary cylinder, reforms the gas valve and packing technology, increases the air volume, prevents leakage and improves the operation cycle.
(8) Hydrogen recovery can be modified by techniques such as membrane separation or pressure swing adsorption as needed.
2. Reform of urea process technology
It is necessary to adopt pre-separation and pre-rectification process; set up a suction tower external cooler to increase absorption capacity; reform a section of evaporation and two-stage evaporation heater; ammonia pump, methylamine pump, etc., according to the situation, change to frequency conversion speed regulation, update and reform; A deep hydrolysis system was added to recover the urea process condensate; the pelletizing tower uses a new type of nozzle.
In terms of automation control, DES system optimization control is adopted. In terms of public works, new technologies such as new cross-flow cooling towers and new types of packing should be used to transform the cooling water system; the boiler adopts circulating fluidized bed technology, mixed with gas-making furnace slag, combined heat and power, and multi-stage energy utilization.
Second, must be centered on economic benefits
Through the fact that the fertilizer market has been weak in recent years, we fully realize that economic benefits are the foundation of the company. Regardless of which technology, which process, and which equipment, it is necessary to discuss and demonstrate inputs and outputs in detail, and carefully calculate economic benefits. Improving economic efficiency is the starting point and destination of all our work (including technological transformation and business management, etc.). Without this, everything is meaningless.
The medium nitrogen transformation cannot simply increase the capacity by adding equipment. It is necessary to improve the technical level, reconstruct the “bottleneck†part of the installation, tap the potential, and aim at less investment and more output to achieve the best economic benefits.
Third, tap the potential transformation and expand the scale to achieve serialization and scale
At present, the ammonia plant of the national nitrogen fertilizer plant has reached a scale of 80,000 t / a. This was the economic scale at the time of the "Eighth Five-Year Plan". The Anyang Fertilizer Plant boldly explored the original system by using the original equipment and adopting new technology. The scale has been expanded to 120,000 t/a. This is an experience worthy of promotion and reference from other factories. In 1996, the Ministry of Chemical Industry held a national seminar on the development of the nitrogen fertilizer industry at the Anyang Fertilizer Plant. The plant has already proposed this idea, but it has not been fully recognized by everyone. Through the practice of the past two years, they have already implemented this idea and achieved good economic benefits. The energy consumption per ton of ammonia can be reduced by 6.3-7.5GJ, and the cost of urea production is reduced by about 20%. Although the process and equipment of China's medium nitrogen fertilizer plant are different, but they are similar, they can be modified according to the model of Anyang Fertilizer Plant. If the national chemical fertilizer plant with coal char as raw material is first modified 20 sets, that is, the synthetic ammonia is increased from 80,000 t/a to 120,000 t/a, and the urea is increased from 120,000 t/a to 200,000 t/a. It can increase the ammonia production capacity by 800,000 t/a and the urea capacity by 1.4 million t/a, which is equivalent to an increase of three 300,000 t/a ammonia plants, and the investment is much more than the new one. This is a good way for the technological transformation of nitrogen fertilizer in China. In recent years, in the competition of market economy, a group of small fertilizer enterprises have emerged, and their scale has reached the scale of medium nitrogen fertilizer. How to further renovate this batch of small fertilizers, the program needs to be studied carefully, and it should be as close as possible to the scale of the economy.
Regarding the transformation of raw material routes, the conditions of different plants are different, and the conditions are different. It is necessary to fully demonstrate according to their different characteristics, and it is not possible to strive for consistency according to local conditions.
Fourth, attach importance to product structure adjustment and develop diversified operations
Most of China's nitrogenous fertilizers are old factories that have been in operation for several decades. Many factories have several or even dozens of products, and there are few single production plants. This is a very important product structure adjustment and development of diversified operations. Good foundation. For example, Zijiang Nitrogen Fertilizer Plant has done a good job in this regard. The plant not only produces mixed fertilizers for agrochemical services, but also develops a variety of fine chemical products.
In addition, the nitrogen fertilizer products of the factory are relatively single, and they cannot withstand the market storms. Even if they have some products, they will not be able to form a climate. In the future technological transformation, we must pay attention to the development of diversified operations and cannot do singles. It is necessary to take fertilizer and chemical industry together, and take the road of fertilizer and diversification. However, when determining the product plan, it needs to be studied carefully. There are two issues to be addressed: one is the market; the other is the source of technology. Otherwise, it will form a burden.
V. High innovation and development capabilities
Many medium nitrogen fertilizer plants have achieved significant economic benefits in this regard. Some factories use the new technology and new technology of some institutions of higher learning, scientific research units and brother factories to carry out technological transformation of the factory. In the future, the transformation of the medium nitrogen fertilizer plant should also strengthen the links with these departments. It is also possible to introduce some foreign technology, "take the longest, and make up for it." At the same time, we must also improve our ability to develop and innovate, engage in small reforms, and increase investment in this area. At present, our medium-nitrogen fertilizers are not strong enough to adopt new technologies, and they are not bold enough to change their mindset. The 21st century is an era of knowledge economy. Whoever has new technology will take the initiative, who will occupy a favorable position in the market competition and occupy the commanding heights of the market economy.
6. Strengthening air-conditioning regulation and maintaining fair competition order
I am referring to the entire nitrogen fertilizer industry here.
In 1994 and 1995, the domestic fertilizer market was popular. A large number of new plants were installed in various factories. The state has also approved a number of projects. The nitrogen fertilizer capacity has increased rapidly. In addition, the country has imported a large amount of chemical fertilizers, which has caused the current situation of slow sales of domestic fertilizers. We should sum up experience, learn lessons, strengthen macroeconomic regulation and control of the fertilizer market, and control fertilizer imports. To control those
It is only an item that relies on extension to improve efficiency.
In the recent period, the reform of state organs and institutions, the management of the industry has been weakened, and the industry has encountered some new situations, such as insufficient liquidity, mutual arrears of corporate triangular bonds, and disorderly market competition. The government's competent department is not very clear. It is recommended that the state strengthen industry management and maintain a fair and competitive order. I hope that the relevant industry management department will send relevant investigation teams to the enterprises to conduct in-depth investigation and research to help enterprises solve difficulties.
In addition, industry statistics are inaccurate, some figures are large, and macro-decisions lack reliable basis. Fertilizer enterprises are very eager to pass the "Fertilizer Law" as soon as possible to safeguard the interests of enterprises, and so on. These are all areas of industry management that need to be strengthened.
7. Appropriate preferential policies should be given to the transformation of medium nitrogen fertilizers.
Fertilizer is a kind of civilian material that is related to the national economy and the people's livelihood. The solution to the problem of chemical fertilizer can only be based on domestic. China is a big agricultural country. The international fertilizer market is directly affected by the demand for fertilizer in China. Too much dependence on imported fertilizer will inevitably lead to an increase in the price of fertilizer in the international market. This has been learned in history. Therefore, domestic production of fertilizer cannot be abandoned due to poor efficiency. The state should give appropriate preferential policies to encourage fertilizer production. Specifically, there are suggestions in the following areas:
(1) Increase the strength of loans. For the “Eighth Five-Year Plan†and “Ninth Five-Year Plan†projects, national and local loans should be put in place in time, and the project should be completed as soon as possible. The loan interest rate should be appropriately discounted.
(2) For the key equipment introduced, the customs duties and value-added tax shall be exempted.
(3) The existing medium nitrogen fertilizer enterprises should give the same preferential policies as small fertilizers in raw materials, power supply, transportation, taxation, etc., and implement fair competition.
(4) Bank loan guarantee and chemical fertilizer technical transformation projects should be given preferential policies (such as the company's own guarantee).
(5) Continue to maintain the country's existing fertilizer and reserve fund system.
Thoughts on technical transformation of medium nitrogen industry
Gu Zongqin
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