Texaco gasifier level

The liquid level in the quench chamber is low; if it is below 5%, then 1. Interlock shutdown occurs； 2. Car jumps out of the lock hopper; the slag locking valve closes as a result of interlock ； 3. The black water discharge valve of the gasifier is interlocked to close. The flow rate of the quench water is too low; there should be an interlock to shut down the system, otherwise 1. the quench ring will get damaged ； 2. The temperature of the process gas at the outlet of the gasifier is extremely high. It is also necessary to install a low-liquid-level trip interlock in the water washing tower; this can be handled according to specific circumstances. The key is to enable early detection through process controls, and to adopt appropriate methods to regulate the liquid level in the tower in order to prevent the cooling water pump from running dry due to low liquid levels.

Setting the interlock for the quench chamber liquid level at 5% trip seems a bit inappropriate; this liquid level is too low. Our plant is equipped with a interlock at a quench chamber liquid level of 15% (this value was determined through discussions between the design institute and GE Company; the size of the gasifier is 3200mm*3800mm). It is very necessary to set up a interlock for the quench water, just as mentioned above. As for the liquid level interlock for the carbon scrubber, it’s not very useful and can be completely omitted.

With too many interlocks, the system tends to shut down frequently. However, aspects such as the flow rate of the quench water and the liquid level in the scrubber can be ensured through proper design; for example, if the liquid level in the scrubber is low, water can be supplied through a backup channel – this is something that can be achieved. It’s still best to have interlocks for the liquid level in the vaporizer as well, to protect the components inside the furnace

The interlock that causes the furnace to shut down when the liquid level is low can be omitted, as the personnel on duty will notice this alarm in such situations; this is something that all operators should pay attention to at the very least. When the liquid level in the quench chamber of the gasifier is low, the built-in interlock causes the XV1308 valve to close; under normal conditions it is a normally open valve. This prevents the liquid level from continuing to drop, and the drainage will also be stopped; it’s XV1312. If there is a problem with the cooling water pump, we will turn on the direct make-up water to supply water to the vaporizer. At the same time, it is necessary to reduce the load and minimize water loss, monitor the outlet gas temperature TA1309, to prevent an unexpected shutdown due to high outlet gas temperatures. If the above measures cannot save the gasifier, a manual shutdown can be performed.

Up there, stop discharging the black water, and also stop discharging slag from the lock hopper. Even if the liquid level in the gasification furnace can be controlled, the ash and slag generated by continued feeding will accumulate at the slag discharge outlet, and the quality of the water in the gasification furnace will deteriorate. If the slag discharge outlet gets blocked, the high pressure difference in the gasification furnace could cause the system to shut down !

Please change the valve codes to nouns; the valve codes may vary from company to company. I didn’t understand the sentence \"We will turn on the direct water supply to fill the gasification furnace\" – are there any missing characters?

Haha, there are three options for the low liquid level interlock in the vaporizer; this interlock should be activated during operation! For safety! There is no need to install a low-flow trip interlock for the quench water; the vaporizer system already has a low quench water interlock. When the quench water level is too low, the emergency quench water supply valve will open fully. In our plant, this valve is of the air-operated type! There is even no need to install an emergency shutdown interlock for the water wash tower, as there is enough time to deal with it!

This post was last edited by shanxg on 2009-6-18 at 20:54. The original poster could actually go and visit various manufacturers of valves to learn more about them

I disagree with the view on the 5th floor; the liquid level of the vaporizer must be monitored during normal operation. Indeed, these two valves close automatically when the liquid level is low, but this level is only slightly higher than the shutdown value. As for the low liquid level in the gasifier causing these two valves to close in sequence, this is mainly to prevent gas leakage due to low liquid levels, and it is not intended to protect the liquid level in the gasifier. If there is a problem with the cooling water pump, the backup pump will start automatically. Supplying water to the gasification furnace directly via the deaeration water pump by manual means is a last-resort option and is not used under normal circumstances. Furthermore, during operation, unless there is an operational error or a problem with the lock-hopper control system, it is impossible for the level in the gasification furnace to reach the shutdown value instantly. If the low level in the gasification furnace is caused by water contamination, I support lifting the interlock related to the coolant chamber level as a means to assist in dealing with this issue. One last thing to mention is that the unit where the original poster works does not have this interlock related to the slag port pressure difference

Answering the question from the friend above. We don’t have a standby pump for cooling water; there is one pump per boiler. If that pump fails, we can only use direct water supply. It’s of course good to have a backup pump; it saves a lot of hassle. The slag port pressure difference you mentioned should refer to the pressure difference in our gasification furnace, that is, the difference between the pressure inside the gasification furnace and the pressure at its outlet. This parameter indicates whether there is a blockage at the reaction slag port, if there are any issues with the downcomer, and whether the liquid level in the quenching chamber is normal.