Regarding the issue of direct thermal supply of hydrocracking feedstocks?
Thread Content
The feedstock for the hydrocracking unit consists of normal paraffins, light paraffins, medium paraffins, heavy paraffins, and catalytic diesel; the feedstock is supplied from storage areas. If the process is modified to use direct feeding, the feed temperature will increase, thereby reducing the thermal load on the furnace. Are there any units that use such a feeding method? What are those security risks? Will automatic backwashing to the sludge tank affect stability and cause it to volatilize into oil vapor?
Many hydrocrackers now use hot feed; it is necessary to pay attention to the temperature limits of the feed tanks and feed pumps. If heat exchangers are used, their design parameters must also be taken into consideration. Automatic backwashing to the sludge tank should be fine; there shouldn’t be any problems with the volatile vapors being sent to the flare. Additionally, the temperature should not have exceeded the initial boiling points of diesel and wax oil.
Direct feeding is normal; in addition to what was mentioned on the second floor, it is also necessary to consider the stability of these feedstocks, including the stability of their flow rate and quality, in order to avoid instability in the operation of the cracking unit
It is primarily calculated based on the equipment’s design temperature and flow rate, with the result then being kept within the designed range!
If the direct feed material does not have a stable feed flow rate from the storage tanks in the irrigation area, for example when blending catalysts for diesel production, the amount of such catalysts used in the upstream facilities will vary to some extent; does this mean that the properties of the raw material are unstable? How to control it? Adding a control valve will cause pressure buildup in the upstream equipment, preventing it from delivering fluid!
It would be better to use a larger buffer tank. Flow control valves and flow meters are definitely necessary; only by installing them can feed stability be ensured. As for the pressure buildup of materials at the upstream unit, I think this can be resolved through staged control – first ensuring that the amount of material flowing from the upstream unit to the downstream unit is adequate, and any excess still needs to be sent to the storage tank area
Well, the volume can be controlled; if it’s not enough, won’t they stop sending more to the irrigation area? First of all, it is necessary to ensure a stable supply of feed; it shouldn’t change with fluctuations in the upstream process After all, the yield is not constant
Even in cases where the quantity is small, it still needs to be delivered
Primarily, the temperature and quality of the raw materials have a significant impact on the hydrogenation unit. Previously, the feed came from the tank farm, and the temperature of the raw materials was relatively stable; however, after direct feeding, the temperature of the atmospheric and vacuum distillation units directly affects the hydrogenation unit. Changes in the properties of the extracted material also directly affect the hydrogenation unit. Direct supply for energy savings is the trend, but it comes with higher requirements for operation, whether in upstream or downstream equipment.