Analysis and countermeasures for the operation of air compressors Zhang Lidong Shao Kuiming (Tanggang Oxygen Factory) began to analyze and find out the real cause of the accident, and then implemented improvement measures to prevent the recurrence of similar accidents.
1 DH 71 air compressor construction overview DH 71 air compressor is an air compressor produced by Hitachi, Japan, and is the main equipment of Hitachi six thousand oxygen generator. The air compressor is connected to the motor through a gear coupling. The two pairs of impellers are respectively installed at both ends of the low speed and high speed gear shafts. The two pairs of gear shafts are meshed by a large gear coupled with the motor, and the two pairs of gear shafts are large. The gears are mounted in a gear tank. Each gear bearing bush is lubricated by forced lubrication in the gear oil tank. The gear oil tank is horizontally split, and the contact surface is finely machined to prevent the oil in the oil tank from leaking outward. The two gear shafts pass through the portion of the oil tank casing and the volute of the impeller. Some of them use labyrinth seals (see Figure 1). These labyrinth seals prevent oil in the tank and gas in the impeller casing from leaking into the environment. The stages of the air compressor are independently installed in the lower part of the air compressor main body.
2 Accident Case Case 1: On October 8, 1993, a fire accident occurred in the soundproofing room of the air compressor intercooler, and no major equipment accident was caused due to the discovery of the rescue.
Case 2: On February 5, 2000, after the air compressor was just started for less than 5 minutes, the operator found that the air compressor was surrounded by a large amount of oil mist. From the gear oil tank total oil return pipe speculum, the oil return was less than normal. Many, the oil level of the main fuel tank is also reduced by 10cm compared with normal. After detailed inspection, it is found that there is oil pollution in the condensate drain of each level of the cooler, and it is forced to stop the degassing of the air coolers at all levels of the air compressor gas pipeline.
3 Accident analysis (1) Case 1 analysis: In recent years, the oil leakage phenomenon of the air compressor gearbox has not been solved. The lubricating oil from the shaft head oil labyrinth seal and the upper and lower contact faces of the gear box penetrate into the lower part of the air compressor main engine. The intercooler enters and exits the sound insulation layer of the gas pipeline (the sound insulation material is asbestos rope and slag wool), due to the long-term oil leakage during the operation of the air compressor and the high temperature of the outlet pipeline (the air compressor exhaust temperature is around 130 °C) ), the sound-insulating layer of the pipeline forms an oil-like carbide, and the sound-insulating layer on the pipeline causes the metallurgical energy source at a high temperature to be released in a period of 19, 2000, and the amount of the oil-like carbide on the sound-insulating layer is spontaneously ignited.
(2) Case 2 analysis: When the air compressor is just started, the inlet guide vane valve is fully closed according to the operating procedure, and at this time the impeller works at the high speed (7965r / min) on the original air and along the discharge valve ( At this time, the discharge valve is fully opened and discharged. After the original air is exhausted instantaneously, the air cannot be sucked in from the inlet guide vane valve, and it can only be forced to pass through the labyrinth seal at each level (B in Fig. 1). Air (normally, because the pressure inside the impeller casing is higher than the external pressure, the air leaks along the labyrinth seal B to the outside C), causing a vacuum zone around the C outside the labyrinth seal B, thereby increasing the D in the gear tank. The pressure difference at the outside increases the amount of oil leakage from the labyrinth seal A to C, and a large amount of oil leaks along the labyrinth seal B is sucked into the impeller, and the air is compressed step by step and attached to the intercooler gas at each stage. On the side and on the pipe.
4 Improvement measures and preventive measures (1) Measures to reduce oil leakage 1 Use new materials to reduce oil leakage at the contact surfaces of the upper and lower tanks of the gear box. The upper and lower contact surfaces of the gearbox have good contact accuracy when the equipment is shipped from the factory, which ensures a good combination of the two without leaking oil. Since the gearbox is at atmospheric temperature (about 25 °C) while parking, and it is about 70 °C during operation, this creates a temperature difference, causes thermal stress, and eventually deforms, destroying the contact effect between the upper and lower parts of the gearbox. At the time of the gearbox joint surface, the Manjianghong sealing paste which has been solidified to ensure good contact during the last inspection is scraped off with a scraper, which will inevitably cause damage to the two joint surfaces and make it surface smooth. The flatness deteriorates.
The performance of various sealing materials was compared through trial and error. We selected the oil-resistant sealant produced by Xinxing Chemical Plant in Yucheng County, Hebei Province. The method is as follows: the upper and lower sides of the gear box are cleaned, the oil quality is removed, and the glue is evenly applied on the upper and lower sides, the thickness is 1 mm, and after waiting for 10 minutes, the two are fastened together, so that the two joint surfaces can be overcome. Bad shortcomings.
2 Improve labyrinth sealing conditions and reduce labyrinth seal leakage.
In order to lubricate the bearing bushes and the gears in the gearbox, these places are provided with pressure to the oil pipes leading to the oil pipes flowing through these places to take away the heat generated in these places and the temperature itself rises, generating partial oil vapor, resulting in A certain oil vapor pressure is formed in the gear oil tank. Under this pressure, the oil vapor leaks along the oil labyrinth to the external environment. (In this air compressor oil system, although a 0.4 kW exhaust fan is provided to prevent the gear box from being desired The pressure has increased, and now it seems that it can not meet the requirements).
According to the formula of the labyrinth seal principle: G——the leakage amount of the labyrinth seal to the outside of the machine, kgf /s——correction coefficient D——the labyrinth seal shaft diameter S——the gap gap Z——the number of labyrinth seal teeth r—gas Density - the internal and external pressure of the labyrinth seal.
It can be seen from the above formula that reducing the oil vapor pressure in the gearbox and reducing the labyrinth seal gap S are all effective ways to reduce the leakage amount G of the labyrinth seal. To this end, we installed a vacuum separation oil vapor device at the upper mirror of the original gearbox (as shown in Figure 2). 5毫米。 The minimum gap gap S of the crude oil labyrinth seal A is reduced from 0. 2mm to the current 0. 15mm.
19 volume 6 period 2000. 11 metallurgical energy operation rate annual operation time, hourly production, shift output, description: billet single weight: 1. t annual output: 1 million tons unit consumption: 28kg / t year-round time: 8760h reduce unit consumption It is especially important to take hot billets into the furnace and increase the ratio of hot billets into the furnace, which is in line with current energy saving ideas and trends.
The kiln heating calculation model is used to analyze the energy saving effect of the hot billet into the furnace, and the steel billet is increased from 0 ° C to 200 ° C. At this time, the billet is heated in the furnace at 0. 859 h, converted into steel burning amount. 234t / h, heating time at 0 ° C is 1. 193h, the amount of steel burning 168t / h. It shows that in the case of the heating system of the various sections of the furnace, the temperature of the furnace billet is increased by 200 ° C, and the furnace burning capacity is increased by 66t / h (increased by 39).
According to the heat balance calculation of the heating furnace during the three-line rolling, the output increases, the billet exit temperature does not change, and the thermal efficiency does not change. When the temperature of the billet increases by 200 °C, the fuel consumption per ton of steel decreases. 6 Conclusion In summary, The maximum furnace burning capacity of the furnace determined by the calculation of the rolling mill capacity, the heating furnace body and the exhaust system capacity is 165t / h. We believe that the current production status of the furnace is already in the economic zone, and the unit consumption level reaches the special furnace standard, the heating furnace Each system is close to the rated capacity. If the furnace output is forcibly increased, it is necessary to increase the heating load of the heating section, improve the smoke exhausting capacity, and increase the speed of the rolling mill. It is particularly important to increase the operating rate of the rolling mill under the condition that the existing furnace conditions are unchanged. Increasing the ratio of hot billet into the furnace has obvious effects on a series of economic indicators such as energy saving and consumption reduction.
1 high speed rolling mill wire production. Beijing: Metallurgical Industry Press, 1995 2 Reference materials for industrial furnace design of steel plants. Beijing: Metallurgical Industry Press, 1979 3 Industrial furnace thermal engineering and construction. Shenyang: Northeast Institute of Technology, 1983 Zhang Changbao Editor 1 - Oil Vapor Emissions 2 - Factory Boundary Wall 3 - Oil and Gas Pipeline 4 - Oil Vapor Condensation Separator 5 - Oil Vapor Pipe 6 from Gear Oil Tank - Gear The internal pressure of the fuel tank (Pa) 7 - the upper part of the gear oil tank 8 - the oil vapor is condensed into oil and returned to the main oil tank (2) to prevent the oil vapor from entering the air compressor air passage without changing the inlet guide vane valve of the air compressor Next, we will partially modify the operating procedures, that is, the inlet guide vane valve is closed when the air compressor is started, and the inlet guide vane valve opening degree is changed to 5 when the air compressor is started (10 to 30 is the surge area).
5 Conclusion After we implemented the above-mentioned plan in April this year, the air leakage problem of the air compressor was fundamentally improved. When the oxygen was started, the air-side condensate discharge pipe of the air compressor final stage was sampled and analyzed. The air is free of oil. This eliminates the recurrence of fire and oil vapor into the air compressor gas passage accident from the source.
Zhang Changbao edited metallurgical energy, 19 volumes, 6 issues, 2000. 11
The objective of a turbocharger is to improve an engine's volumetric efficiency by increasing density of the intake gas (usually air) allowing more power per engine cycle. The turbocharger's compressor draws in ambient air and compresses it before it enters into the intake manifold at increased pressure.
We are specialized in making and exporting European Truck spare parts , mainly air brake valves like Unloader Valves ,clutch servos,air dryers ,foot brake valves,Hand brake valves, air pressure Control Valves and so on .and also auto brake valves for Japanese trucks such as Nissan,Hino,Isuzu .meanwhile ,we deal with Iveco spare parts like bumpers, Sensors ,lamps,body parts,rediators,clutch disc, clutch cover,cables etc.
Iveco truck turbocharger,Turbocharger for Heavy trucks,Turbocharger for European trucks,Fiat truck turbocharger,Turbocharger TD04L
SHANGQIU FLAT WORLD MACHINERY CO.,LTD , https://www.flatworldtrucks.com