I would like some advice on certain issues related to the SW ethylene process.

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I would like to ask the experts here some questions regarding the SW ethylene process; thank you for your guidance. Butter skimming in the alkali washing tower – what is the final treatment method for the butter? In other words, how should the waste oil from the alkali washing tower be dealt with? Returning to the water wash tower often leads to oil-water emulsification. After the butter is separated, it generally undergoes two stages of preliminary separation using oil, alkali, and water, with the alkaline solution being used to remove excess alkali and prevent oxidation. Where does this oily waste usually go? How is it best to handle this? Principle for determining the flare emission volume of the ethylene plant: the sum of the emissions from the wash tower and the propylene unit. Why a propylene addition machine? It depends on the discharge amounts from the top of the wash tower and the propylene unit in the event of a fault in the circulating water system. If there is a problem with the circulating water, the propylene unit has to be shut down and discharge is required; similarly, the ethylene unit cannot operate either, so discharge is necessary in that case as well In the SW process design, the liquid phase from the second stage tank of the ethylene plant, at a pressure of 1.75 bar, is sent to the top of the demethanization tower as a coolant for the self-reflux heat exchanger. After absorbing heat during vaporization, it returns to the first stage tank, with a backpressure of generally 0.3 bar. However, there is often a problem of insufficient refrigerant driving force. In actual production, many units introduce a gas phase after the liquid-phase feed control valve to create a two-phase flow of vapor and liquid, thereby generating a vortex flow and increasing the driving force for fluid movement. Last time, I heard someone from the design institute say that as long as there is a sufficient difference in valve positions between the two-stage tank and the liquid refrigerant control valve, this problem won’t arise. Why? Can this voltage difference, by creating a pocket shape, prevent the problem of insufficient driving force? How to understand it? For carbon trihydrogenation catalysts, regeneration and reduction involve substances such as CH4/H2/N2/steam – when is each of these processes used? The destinations also include going to the flare, being vented on-site, and burning in the furnace of the cracking unit – how is the process switched between these options?