Please tell me the purpose of using steam as the medium when the gasification furnace is started.

The air may be unsafe to flow back, and a compressor is required. The steam pipe network can be used directly. The water seems to be unable to be vacuumed. . .

I think that as long as the suction device is designed properly and the fluid flow rate is high enough, negative pressure can be extracted. The same is true for water. If there is a water jet vacuum pump, the principle is the same. I think the backflow of air has nothing to do with it, because the oven is used for extraction at startup, and there needs to be air in the oven to burn the fuel gas. At this time, there is no danger even if the air flows back. In addition, if the air flows back, there will be no extraction effect. This operation should be avoided as much as possible.

In order to completely replace the system and prevent the oxygen content from exceeding the standard, it is unsafe. Nitrogen can also be used.

Both air and nitrogen are acceptable, as long as they meet the quantity requirements. SHELL oil gasification design uses three media, steam, nitrogen and air.

According to the location of the extractor and the nature and source of the steam, it is better to use steam. On the other hand, using steam consumes less energy, while using other gases can consume a certain amount of energy.

First, it uses a Venturi nozzle structure to inject fluid at the throat to increase its flow velocity, increase its kinetic energy and decrease its pressure energy, until the pressure drops below atmospheric pressure and generates a suction effect, which draws the medium in the suction pipe into and mixes it out. Therefore, any fluid with sufficient energy can be used as an ejection medium. Personally, I think that the choice of ejector medium is related to the configuration of the factory's public works. Compressed air or nitrogen is relatively limited by equipment investment and production capacity. If the extraction equipment is improperly used, medium cross-flow may occur, but the probability is not very high. ； The advantage of steam as an extraction medium is that it has a large public supply margin, is relatively clean and cheap, and can provide more extraction space after phase change. ； Water as the injection medium generally requires corresponding power equipment and system matching... The main function of gasifier startup extraction is as the air extraction power of the oven and the replacement of the gasifier system during startup and shutdown. Personally, I feel it is better to use steam. Ignorant and fearless

The key is that parking and replacement is more dangerous. If the air pressure supplied after reaching a certain vacuum level drops unexpectedly, reverse flow may occur. Cross-flow steam is not a big problem. Anyway, I feel that if combustible gas and air are connected in a system, special care must be taken. The actual situation is unpredictable. You can't tell where there will be dead ends, or they will be connected in some unpredictable way. Start and stop work are often chaotic. It’s not absolutely impossible to use it, but it’s better to be cautious. In fact, for equipment like this that has been activated for a short time, in the overall operating cost, it is estimated that material consumption is not the main factor, and equipment investment is more important. The details can be calculated. If steam and nitrogen are readily available, the jet pump does not require power equipment. This post was last edited by RainWolf on 2009-3-5 19:00 ]

The main reason for using steam is that the working range of the steam injection pump is from 730~10-4mmHg； The working range of the water jet pump is 200~730mmHg, and generally it can only maintain the vacuum degree at 680~700mmHg. From this point of view, steam injection has a better vacuum effect. In addition, as for not using air or nitrogen, I think the main reason is that the cost is too high, and a compressor must be added, which requires a lot of maintenance work.

The cost-saving argument is understandable. I personally think that using air or nitrogen will have good results. It is convenient to use the steam directly from the thermoelectric

You can use steam or air. The key is the flow rate of the medium. It can be used as long as the flow rate meets the requirements, but the pumping force is stronger with steam, but pay attention to hydrophobicity (to prevent poor hydrophobicity from affecting the pumping load and causing the steam condensate to flow back and burn people). Air can completely meet the requirements, and the air pressure from the air compressor can also be used.