The issue of furnace tube layout in atmospheric pressure furnaces and reduced pressure furnaces

Are the two furnaces of the same model and have the same processing capacity?

What size are your units? I’ve never seen horizontal pipes in the radiation chambers of vacuum distillation furnaces; horizontal pipes are used in the convection chambers. Are you dealing with small units, those with a capacity of a few hundred thousand tons? Horizontal pipes are generally used in situations where coking is likely to occur, where there are impurities present, and in systems with a gas-liquid mixture, as they facilitate coking removal and ensure stable flow. This does fit the characteristics of vacuum distillation furnaces, but it seems that large-scale units don’t use horizontal pipes, due to other constraints such as space limitations.

I’ve seen newly designed large refineries in which the furnace tubes are arranged horizontally; this is likely done to increase the usable area of the furnace, prolong the time oil stays inside the furnace, and thus save on investment costs. Furthermore, for heating furnaces with a higher design height, a horizontal arrangement with material entering from the top and exiting from the bottom can reduce the pressure drop across the furnace tubes, facilitating shutdown and purging.

In the past, the heating furnaces in atmospheric and vacuum distillation units all used cylindrical furnaces, with vertical furnace tubes being employed due to space constraints. In larger units, square-shaped furnaces were used, and in such cases the vacuum distillation tubes were arranged horizontally. As mentioned by the third speaker, \"Horizontal tubes are generally used in situations where coking is likely to occur, where there are impurities present, or in systems with a gas-liquid mixture; this arrangement facilitates coking removal and ensures stable flow.\" Horizontal tubes were used for the atmospheric distillation tubes in order to prevent an excessive amount of vapor from accumulating inside the tubes, which could hinder heat absorption by the material being heated and lead to an increase in the temperature at the top of the furnace, thereby raising the exhaust gas temperature as well

The radiation chamber and the convection chamber are different: the radiation chambers use vertical tube arrangements, while the convection chambers employ horizontal tube arrangements

Really? The heating furnace in the pressure reduction tower I’ve seen is a vertical tube, not horizontal

I’ve never seen this type before; there might be some special manufacturing requirements

Horizontal furnace tubes are used when the medium inside the tube tends to coking, as this facilitates coking removal. For our 2.5 million tons of atmospheric and vacuum distillation, the vacuum distillation furnaces use horizontal furnace tubes of the radial type.

I’ve also never seen the furnace tubes in the radiation chamber of a pressure relief furnace arranged horizontally. Are you considering coke cleaning or uniform heat transfer? I would like to ask the original poster and everyone else: is the outlet of such a stress-relief furnace expanded? Inject steam? Thank you first.