1 energy-saving design measures 1. 1 air compressor 1) rational design selection. The exhaust pressure of the air compressor directly affects the energy consumption of the air compressor. The coal injection process of the blast furnace system of the Maanshan New District requires a supply pressure of 1.15M Pa, while the supply pressure of other pressure users is less than or equal to 0.8 MPa. Therefore, the design is as accurate as possible under the condition of ensuring the lowest supply pressure. For the pressure loss during the gas supply process, the air compressors with the exhaust pressure of 1.25M Pa and 0.95M Pa are separately supplied with gas to avoid unnecessary high pressure and reduce energy consumption.
Like the exhaust pressure, the displacement of the air compressor is also an important factor affecting its energy consumption. The determination of the air compressor exhaust volume not only needs to calculate the consumption and leakage of each user, but also fully considers the time volatility of the compressed air. The selected air compressor unit should have good adjustability of the exhaust volume. The air compressor of the air compressor station in Maanshan New District has two control modes: constant pressure and automatic. When the gas consumption is stable, the constant pressure control is adopted, the valve is steplessly positioned, and the whole process is adjusted by 0 100% to improve the gas supply stability; When the gas fluctuation is large or low, the automatic double control (that is, the constant pressure control and the upper and lower limit pressure control when the flow rate is low) can be used, which can effectively save energy and ensure the best comprehensive ratio of gas consumption and energy consumption.
The important performance indicators for measuring the energy-saving level of air compressors are efficiency and specific power. Therefore, when designing and selecting, air compressor units with high efficiency and low specific power should be selected as much as possible. The air compressor rotor structure selected by Maanshan New District is a single-axis single impeller. Each rotor short-axis has a working impeller independently. This structure not only allows each stage of the impeller to work at the optimum speed, but the speed of each stage is different. The best matching, the highest efficiency of the whole machine, the energy consumption is 3% lower than other similar units, and each stage has an independent thrust bearing to bear the axial unbalanced force, the axial force is unidirectional, predictable, and can meet the overload Change or even start frequently, minimizing energy consumption. The selected air compressor is a full-floating graphite ring seal. The leakage of compressed air per stage is less than or equal to 0.3%. The total leakage of the whole machine (three-stage compression) is not more than 0.9%, which is much lower than the traditional maze. Mechanical seal (1% 3%). In addition, the air compressor cold and aftercooler are designed outside the patented water pipe and gas pipe. The air travels with the inner fins in the cooling tube, which is a straight line, which reduces the resistance, compact structure and high cooling efficiency; the water goes outside the cooling tube, which is equivalent to the natural soundproof cover, so that the noise during the operation of the compressor does not exceed 85dB. It is the lowest noise compressor in the world; the cooling tube and fins are made of copper, the heat transfer efficiency is 10 times that of stainless steel; the water shelling process, lateral scouring, good heat transfer effect, good anti-pollution performance, not easy to scale; copper The tube cooler has no limitation on chloride ions, total solids, conductivity, and the like in the cooling water.
2) Reasonably design the air intake pipe of the air compressor. The air compressor intake pipe of Maanshan New District adopts large diameter stainless steel pipe, which is short and straight, and the air filter is high. The intake pipe and air filter adopt a similar box design, which reduces the resistance and increases the intake pressure, thereby improving The amount of exhaust.
3) Rational design of the cooling water system. The design of the air compressor station in Maanshan New District mainly takes measures to save energy in the cooling water system from three aspects: water quality, water temperature and cooling water recovery.
The cooling water system uses a circulating water supply system to prevent direct discharge and avoid waste of cooling water. The circulating water uses an open high-level cooling tower system to save investment and reduce operating costs.
Theoretically, the lower the inlet temperature of the cooling water, the better the cooling effect of the air cooler, and the lower the exhaust temperature of the air compressor. However, the determination of the inlet water temperature is also affected by local meteorological environmental conditions. After overall consideration and technical and economic comparison, the maximum cooling water inlet temperature under the most unfavorable conditions in summer is finally determined. 35. Properly increasing the drainage temperature can save water. However, since the air compressor station has a dryer, the dryer is guaranteed. Gas temperature and drainage temperature should be determined according to the specific conditions.
Improving the quality of the cooling water can prevent the air cooler from fouling, improve the cooling efficiency, reduce the power consumption of the air compressor, and save maintenance costs. The cooling water quality of the air compressor station in Maanshan New District meets the GB50050 2007 standard and is confirmed by the air compressor supplier. The cooling water process system is fine-tuned for individual differential indicators, so that the cooling water quality is more closely matched with the air cooler.
Good cooling water not only makes the compression of the air closer to isothermal compression, but also reduces the compression work. Moreover, the air cooler can precipitate as much condensed water as possible, reduce the burden on the drying equipment, improve the efficiency, and reduce the power consumption.
1. 2 air filter (hereinafter referred to as air filter) after technical and economic comparison, the design uses self-cleaning air filter, differential pressure device, secondary filtration, over-size configuration, not only can reduce pressure drop, ensure adequate air intake Quantity; and also extend the life of each filter unit, reducing operating costs.
1. 3 Dryer 1) Generally, the compressed air is separated from the clean compressed air to avoid extremes. At the same time, the dryness requirements of the compressed air of each system are accurately analyzed to reasonably determine the pressure dew point of the clean compressed air.
2) At present, there are three main types of adsorption dryers: no heat, micro heat and heating, and economic and technical analysis of three dryers. Through analysis, the micro-thermal adsorption regenerative dryer has a small amount of regeneration gas, comprehensive economy and good technical indicators. Therefore, the design of the air compressor station in Maanshan New District finally chose the micro-thermal adsorption regeneration dryer as the compressed air drying equipment.
3) Since the amount of adsorbent filling in the micro-thermal adsorption dryer is relatively small compared to the rated treatment amount (ie, the filling amount), the overload use affects the dew point of the finished product. Therefore, the actual treatment volume of the adsorption dryer is controlled within the range of 70% and 80% of the rated treatment capacity. This is the reason why the design of the drying machine of the Ma Steel New District air compressor station is oversized.
2 Conclusion The energy saving potential of air compressor stations is very large, especially in the situation of increasing energy shortage, the energy saving of air compressor stations is more important. In order to achieve good energy-saving effects and benefits, in addition to strengthening the daily management of air compressor stations and maintaining economic operations, engineering design is particularly important. The energy-saving methods and measures adopted in the design process must be combined with the actual situation to make the implementation of energy-saving effects. Compared with the cost, comprehensive consideration, especially to ensure that the gas supply meets the production needs, in order to achieve the purpose of creating the largest possible and long-term benefits for the enterprise, otherwise any energy-saving measures will not be worth the candle.
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