Lockbox pressure relief
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In the factory where we are located, secondary pressure relief was initially used for relieving pressure in the lock hoppers: the first time, the pressure was reduced from around 7 MPa to 0.7 MPa, and the second time, it was reduced from around 0.7 MPa to atmospheric pressure. But now, pressure relief is performed only once, from around 7 MPa to atmospheric pressure, and the pressure relief pipeline is not flushed. I asked the technician about the difference between these two methods, but did not receive a clear answer. I would be very grateful if some of you with more experience could explain it to me!
The two functions of pressure relief—preventing backflow and ensuring safety—are not very different from each other, and there’s no need to flush the pressure relief pipeline at all!
The lock cylinder relies primarily on water pressure; due to the low compressibility of water, only a small amount of N2 is needed to achieve the required pressure. During pressure release, little N2 is released as well. Since it is N2 that is mainly released, there is no need to flush the pressure release lines. As for whether pressure is released in two stages or in one stage, there is not much difference
Two pressure releases actually increase the number of valve operations, raising the likelihood of valve failures, which is very uneconomical.
The rate of pressure release must take into account the pressure changes in the equipment; there should be a specified rate for pressure increase and decrease. After pressure release, the water quality in the lock hopper is poor, containing mainly ash and slag particles, which can lead to wear on the valve sealing surfaces as well as potential blockages in the pipelines.
Hehe, high-pressure deoxygenated water – that’s too luxurious
This is also luxurious, so using nitrogen isn’t luxurious then? Also, using nitrogen for stamping doesn’t seem very scientific, does it? I’d like to ask the person on the 3rd floor: have you seen that factory use nitrogen for stamping? Could you give some details? Thank you
N-gas pressurization is quite new; could you give a detailed explanation about it?
Given that the N2 filling rate is relatively uniform and easier to control, we also plan to use the N2 filling method. Please share the advantages and disadvantages of each filling approach
Regarding the water used for stamping, we use high-pressure gray water, which is cost-effective and not as luxurious as what you use... In response to the original poster, releasing pressure once reduces the risk of blockages in the slag discharge pipes, but care must be taken regarding safety at the inlet of the slag tank; it must be a quite spectacular sight. Discharging slag once also reduces the amount of instrument air needed, thus saving energy
N2 punching? If there is a leak in the inlet valve of the lock hopper, won’t air flow directly into the vaporization furnace? That’s terrible… Although it won’t cause an explosion, it will affect the operation and production of subsequent processes…
I don’t understand why deoxygenated water is needed for slag cooling water – what’s the reason behind this? Please give me some guidance! !
After slag removal, the lock hopper is first filled with high-pressure return water, and then pressurized using high-pressure nitrogen; the nitrogen does not enter the gasification furnace.
Nitrogen filling? ? ? Do you have rotary vane circulation pumps?
hihiyhihiy1, who are you? (Please reply to: huaguiyi@yahoo.com.cn) First, release it from around 7 MPa to 0.7 MPa; second, release it from around 0.7 MPa to atmospheric pressure. The pressure relief pipeline is not flushed. The original design adopted a two-step pressure relief approach, primarily due to considerations such as the need to keep the pressure ratio low and to manage high pressures within the device. Pressure relief ratio for one-step release: 8.5/0.1=85. Pressure relief ratio for two-step release: 8.5/0.7=12, and 0.7/0.1=7. In actual operation, the rate of pressure release during the first step of the two-step release process is very fast. Considering that water is an incompressible fluid, and taking into account factors such as valve wear, a single-step pressure release is adopted, along with the use of flow-limiting orifice plates or the adjustment of hand valves to control the pressure release rate and reduce vibration. ““Do not flush the pressure relief line” is primarily determined based on the on-site piping conditions. Our pressure relief line is located at a high position (V3209); after pressure release, the water in this line flows back into V3208 (which effectively cleans the pressure relief line). As for reducing the amount of water used for cleaning or the amount of instrument air required, energy savings are not the main factor here. This post was last edited by huaguiyi on 2008-2-14 13:08.]
I’ve seen a lot of data, but I agree with what the guy on floor 16 said: it’s cost-effective, and the graywater can be reused after slag removal.
For the 16th and 17th floors, you’re talking about two different types of furnaces. The one on the 16th floor is a Lurgi furnace, which uses pressurized gasification of coal; it has a coal hopper and feeds coal using nitrogen under pressure in a dry feeding process – it’s a device used for feeding coal. Floor 17 is talking about pressurized gasification of water-coal slurry, referring to the slag lock tank and the equipment used for slag discharge. You need to distinguish!