How to choose oxygen production technology in the

2022-08-23
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In recent years, the steel industry has taken a series of measures to effectively promote the removal of production capacity, inventory, cost reduction, make up for weaknesses, and optimize the allocation of stock resources. The report of the 19th CPC National Congress also emphasized that deepening the supply side structural reform has a far-reaching impact on the sustainable development of the steel industry. In 2017, steel prices continued to remain high. Steel enterprises hope to seize this wave of market, but subject to the policy of strictly controlling new production capacity, increasing production capacity through technological progress has become the choice of the steel industry

under the new situation, steel enterprises hope to improve their oxygen production capacity

at this stage, the new situation of the steel industry is as follows:

the global economy continues to recover, exports have warmed up, and the "the Belt and Road" construction will greatly stimulate the steel industry to "go global", with a promising future; Although the growth rate of domestic infrastructure construction investment and real estate investment fell, the overall domestic macro-economy operated well, and the production and sales of the steel industry increased significantly

by taking measures such as banning "ground bars" and eliminating backward production capacity, the steel industry has achieved remarkable results in reducing production capacity; Some regional policies and environmental protection policies have a great impact on the industry, such as the comprehensive treatment of air pollution in autumn and winter in Beijing, Tianjin and Hebei, that is, the "2+26" urban heating season, which limits the production of steel and other industries, has objectively played a great role in restraining the domestic steel production capacity. Market supply and demand have been effectively adjusted. Although steel prices fluctuate, they will continue to remain high, and the profitability and level of the steel industry will also remain high. Lithium chloride production capacity of 18000 tons

the technological progress and industrial upgrading of the steel industry will further release high-quality production capacity, but the general situation of strictly controlling the new production capacity will remain unchanged, prompting the steel industry to increase investment in environmental protection and technological progress, reduce costs and increase efficiency, optimize the industrial structure, and enhance product competitiveness and added value. Improving production capacity through technological progress will become the development direction of the steel industry

in short, the overall development situation of the steel industry at this stage is improving. However, the steel industry is greatly affected by various comprehensive factors, such as raw material price fluctuations, policy effects, environmental protection policies, international trade barriers, downstream product supply and demand, macroeconomic development and so on. For this, various institutions and experts in the industry have different views on whether the good development momentum of the steel industry can be sustained for a long time. In any case, most iron and steel enterprises want to seize this market. Therefore, under the circumstances of strict control of production capacity, equal replacement and elimination of backward enterprises, a considerable number of iron and steel enterprises focus on those technologies that can quickly bring about capacity improvement. Among them, improving the oxygen enrichment rate of blast furnace is a very practical and effective method. In 2017, not long ago, many iron and steel enterprises chose to improve their oxygen production capacity and invested in the construction of many large oxygen production units. A simple and efficient oxygen production method, namely pressure swing adsorption oxygen production technology, was popular

PSA oxygen production technology has outstanding advantages

PSA oxygen production technology realizes the separation of oxygen and nitrogen through adsorbent. Its product is only a single oxygen enrichment without other by-products. It is generally used as a supporting oxygen enrichment in front of blast furnace. Based on the practice of Beijing Beida Xianfeng Technology Co., Ltd., which specializes in the R & D and production of pressure swing adsorption oxygen production technology and equipment in China, the author believes that compared with cryogenic technology, the oxygen produced by pressure swing adsorption oxygen production technology has the advantages of low cost, short construction cycle, convenient load regulation and simple operation, which is very suitable for the recent production increase needs of steel enterprises at the current stage

first, the operation cost of PSA oxygen production is low. The power consumption of 1 cubic meter of pure oxygen (equivalent to 100% purity) is generally 0.32-0.35 kwh. Based on the electricity charge of 0.5 yuan/kWh, its operating cost is about 0.15 yuan/cubic meter of oxygen. Taking into account all the costs of depreciation, labor, maintenance, etc., the cost of 1 cubic meter of pure oxygen is also below 0.3 yuan

secondly, the construction period is short. From civil engineering to installation and trial production, generally speaking, PSA oxygen production can produce oxygen within 6 months. At this stage, steel enterprises are more inclined to choose the way of increasing production with short construction period and quick effect. The device will be put into operation as soon as possible and bring benefits. According to the current steel price, the benefits are very considerable

secondly, it is convenient to adjust the load. After adopting PSA oxygen production, the oxygen in the whole plant will increase. On the basis of ensuring the full power of the blast furnace, more high-purity oxygen can be sent to the steel-making system. In addition, in the long run, if the steel situation turns cold in the future, the load of PSA device can also be effectively adjusted in line with the production plan to further reduce costs

finally, it is easy to operate. For the automatic operation of oxygen production equipment, the enterprise only needs to add 6-8 operators, and the threshold of professional requirements for personnel is low. It is easy to be incorporated into the existing energy system for unified management, which will not cause employment problems to the enterprise

the following is part of the operation data of a pressure swing adsorption oxygen plant invested by an iron and steel enterprise for reference

the iron and steel enterprise has three blast furnaces, one 3200m3 blast furnace, one 2500m3 blast furnace and one 1080m3 blast furnace. For every 1% increase in the oxygen enrichment rate of blast furnace ironmaking, the theoretical yield can be increased by 4.76%, the actual yield can be increased by 3% - 4%, the coal injection can be increased by 12kg/t-13kg/t, and the coke ratio can be reduced by 0.5%; When the oxygen enrichment rate of blast furnace ironmaking increases by 1%, the calorific value of blast furnace gas increases by 3.4%. As hot blast stove gas, blast furnace gas is easier to burn. Considering the production status of blast furnaces, the iron and steel enterprise plans to increase the oxygen enrichment rate of the three blast furnaces from 3 to include the upstream and downstream processes of the traditional painting process 5% to about 4.4%, and the corresponding oxygen volume increases from 39000nm3/h to 49000nm3/h, that is, the pure oxygen volume increases by 10000nm3/h

according to the iron production increase of 3%, the enterprise increased the iron production by 475.2 tons of iron/day. According to the operation time of 350 days and the comprehensive efficiency increase of 700 yuan per ton of iron, the economic benefit is 116.42 million yuan/year

at the same time, the annual input cost (including water, electricity, labor, maintenance, depreciation) is about 20million yuan, so the annual economic benefit is about 96million yuan/year

if compared with the cryogenic device of the same scale, considering the difference of construction period and oxygen cost (calculated according to 0.1 yuan/cubic meter of oxygen), the indirect benefits brought by PSA technology are: save 4 months of construction period, and the one-time benefit is 32 million yuan; The direct cost of oxygen is saved by 8.4 million yuan/year

oxygen enriched large-scale injection is one of the important measures for modern large-scale iron making blast furnaces to save energy, save coke and increase production. Oxygen enriched combustion technology can also promote the utilization of blast furnace gas. Oxygen enriched combustion technology can make up for the lack of low calorific value of blast furnace gas and improve the utilization efficiency. If iron and steel enterprises take improving the oxygen enrichment rate of blast furnace as the starting point, build a pressure swing adsorption oxygen production system of corresponding scale, and increase iron making output through oxygen enrichment and coal injection of blast furnace, considerable economic benefits will be created

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