Are there any peers who use hot feed directly in their hydrocracking units?
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In the hydrogenation unit where I work, the feed is supplied in a hot form – that is, the crude oil from the atmospheric and vacuum distillation processes is fed directly into the unit without passing through a storage tank. The workshop doesn’t allow us to control the amount of feed; it’s up to the atmospheric and vacuum distillation units to determine that amount. However, this approach results in great instability. Are there any colleagues who also use hot feed? How do you control it, and is the operation stable?
1. May I ask about the heat exchanger for the feed oil and the heat exchange with that stream of material? 2. Is there a buffer tank for the feed oil? 3. Does the reactor effluent undergo heat exchange with the feed oil? Is there any cross-stream heat exchange? Once the original poster answers these questions, we will generally have the answers
1. Heat exchange between crude oil and tail oil 2. There are a crude oil buffer tank and a filtered product buffer tank 3. Heat exchange between the reactant and the crude oil; there is a cross-line connection
Our unit can accept feed at both cold and hot temperatures. Previously, we used our own feed valves to control the amount of feed, but recently the workshop was concerned that this might strain the vacuum distillation pumps, so they ordered us to keep the valves fully open and let the vacuum distillation system handle the control. Every time the amount of feed changed, we had to contact the vacuum distillation team; our energy consumption also depended on the amount of feed, and it couldn’t vary too much. However, fluctuations occurred whenever the vacuum distillation system switched tanks, and sometimes even without such switches. This made our hydrogenation process very difficult to manage – it’s really better to use cold feed
It seems the processes are all similar. To be honest, it’s the same with us too; it’s impossible to maintain perfect control. I guess the hydrocracking processes across the country are more or less the same. The feed oil exchanges heat with the tail oil/reactive distillates, and the tail oil in turn exchanges heat with the gas holder. By adjusting the heat exchange between the tail oil and the gas holder, it’s possible to control the temperature of the feed oil. Since I haven’t seen the specific process, it’s hard to say for sure; please give me your QQ number