How to ensure that the catalytic unit operates without flaring

We have similar problems, but in our factory it’s mainly due to the extremely strict environmental regulations. One solution is to heat the stabilization system before starting the engine, to ensure that no non-condensable gases are released, while taking advantage of the buffering effect of the gas tank. Haven’t tried it yet, but I’ll do it next time I drive. Please ask friends with similar requests to give their support.

Manual control of the compressor allows for the regulation of the reaction pressure as well as preventing the compressor from operating intermittently. The key point is that catalytic stabilizers usually rely on heat supplied by the distillation section; after fuel is injected into the reaction zone, the rich gas quickly reaches the compressor, while at this time the bottom of the stabilizer has not yet warmed up. Moreover, increasing the temperature at the bottom of the stabilizer must take into account the thermal balance of the distillation tower, so it cannot happen too quickly. If all of the rich gas is allowed to enter before the temperature at the bottom of the stabilizer has risen, the resulting gasoline will contain a large amount of liquid hydrocarbons, and sending it directly to storage tanks would be dangerous. Therefore, from a safety perspective, if the stabilizer does not have another source of heat to raise its temperature in advance, it is better to vent the rich gas through a flare.

Our main approach at present to ensuring that catalytic fuel injection operates without a flare is: 1. Strengthen training for positions involved in catalytic reactions and fractionation stabilization, and conduct multiple drills to ensure effective communication. 2. Before injecting fuel, start the air compressor at low speed, making sure to manually open the reaction backpressure control valve fully. The stable system has established three circulation paths 4. After injecting fuel, the speed can be adjusted based on the inlet and outlet pressures of the compressor, either on-site or in a controlled environment. Due to the insufficient heat source from fuel injection in the stabilization system, a buffer space can be reserved by controlling the bottom liquid level during cycle establishment. Try to control the high stabilizer bottom temperature in order to reduce the vapor pressure of gasoline. Unqualified liquefied gas can be dumped in the tank area.

Well said. I experienced a situation where, when driving without using a flare, the stabilization system’s temperature rose first; gasoline from the bottom of the stabilizer flowed into the absorption tower. The temperature at the top of the absorption tower exceeded 90 degrees, causing the dry gas to carry liquid with it, which in turn led to the immediate shutdown of the just-started atmospheric furnace. The furnace had to be restarted from scratch, which was really troublesome.

I tend to agree with Mr. HAIWB’s view: it is acceptable not to use a flare, but it is necessary to have the corresponding pressure regulators and stabilization systems in operation; if the control measures are appropriate, it is possible to do without a flare.

The guys upstairs didn’t say it quite accurately! Let’s discuss it! What was said on the third floor, that \"if all the rich gas is introduced before the temperature at the bottom of the stabilizer rises, and since the stabilized gasoline contains a large amount of liquid hydrocarbons, it’s dangerous to pour it directly into the unqualified tank,\" is incorrect! ! ! ! Why does stable early introduction of rich gas necessarily result in gasoline entering the tank area along with liquefied gas? Can you not feed crude gasoline into the stabilization system at this time? In other words, can’t we wait until the gasoline becomes stable before using the equipment? What was said on the fifth floor is even more strange! Will not installing a torch cause the absorption tower to overheat? Could you explain it? The method of not using flares is, precisely speaking, a method of avoiding excessive use of flares; since pressure fluctuations are significant during the startup phase, it is inevitable to use flares. The key is to quickly redirect the rich gas into absorption and stabilization after injecting reactant fuel, so as to prevent a large amount of liquid hydrocarbons from being carried away via flaring from the liquefied gas tank. In other words, the compressor needs to start early, operating at low speed before fuel injection; once fuel injection begins, it can promptly increase its speed to reach a stable operating state. 2. Raise the temperature of the cracking tower in a timely manner to reduce the amount of non-condensable gas at the top of the stabilizer, thereby minimizing losses to the flare. What was said on the fourth floor is great! However, for units that use the middle fraction of distillation or steam as the heat source for the stripping tower, the difficulty of raising the temperature of the stripping tower varies, and this needs to be considered separately. When a steam reboiler is used for the stripping tower, it is easy to increase the stripping temperature. When using a fractional distillation heat source, it is necessary to take into account the operating conditions during distillation; proper coordination is essential. One should not extract too much heat from the intermediate stage, nor should the temperature in the distillation tower be reduced too much, as this will cause problems for both parties! It should be emphasized that there is no need to rush to improve the absorption stabilization system for crude gasoline until the temperature at the bottom of the stabilizer rises In this way, the problem of stable steam carrying air on the third floor will not occur!

We redirected the non-condensable gas from the stabilizer tower to the crude gasoline tank, thereby solving the problem of discharging this non-condensable gas through a flare.

Hehe! What you’re referring to is just the small amount of non-condensable gas emitted during normal production! If the temperature of the separation tower rises too slowly at startup, a large amount of liquefied gas along with non-condensable gases circulates within the system; firstly, is the compressor load sufficient? Second, the absorption tower is very difficult to operate!

As for this argument, I’d like to share my personal opinion； I am an operator for the catalytic unit and compressor. We generally do not use a flare during startup. When fuel is injected into the reaction system and rich gas is generated, the amount of gas at first is very small. The turbine needs to have its primary and secondary feedback mechanisms properly adjusted; as long as these are adjusted correctly and there are no problems with the turbine, and the pressure in the reaction settler can be controlled, there is no need to use a flare to adjust the pressure of the settler. In my role on the compressor station, therefore, no flare is used. It’s just my understanding of catalyst startup in this position.

A few days ago, we successfully restarted the catalytic unit that had been shut down for 8 years! Not a single torch was lit! The main method involves gradually increasing the load on the compressor after injecting reactant fuel to achieve stable pressurization; once the pressure is appropriate, dry gas is introduced into the pipeline network! The crude gasoline fails the quality test first! The distillation in the stabilizer bottom is heated using secondary steam; after fuel injection into the reaction zone, the steam supply is stopped and oil is introduced (the secondary system shares the same pump as the reprocessed oil, allowing for rapid circulation of a sufficient amount of oil!)