We operate a VDU(Vacuum Distillation Unit)heater with COT
higher than 400C.
We would like to know the typical run-length of such heater in other refinery.
How to de-coke the plugging tube? By online spalling? or steam and air decoking? or Mechanical Pigging?
Please note that our VDU is a wet...
The medium pressure(14 barg) condensate in this refinery is sent to a condensate flash drum for recovery of low pressure(3.5 barg) steam.
We have found that the process unit which consume the LP steam near the condensate recovery unit suffer fluctuation of LP steam supply.
There is no flow...
The flue gas from our CDU(Crude distillation unit) heater is heat exchanged with the heater inlet air.
The air preheater is a static type with cast iron fin tube in the upper section and glass tube in the lower section.
There is a DeNOx facility(SCR) upstream of the air preheater.
We...
We have a two stages overhead condensation design in our CDU.
The first stage inlet temperature is 150C and outlet temperature is 120C.
The second stage inlet temperature is 118C and outlet temperature is 60C.
The material for these condensers are Carbon Steel.
We encounter serious corrosion...
Recently we invited two guests to our refinery for teaching us how to increase the combustion efficiency of our big CDU(Crude Distillation Unit) Furnace.
The burner of our CDU Furnace is Combo type, which can burn both Refinery Fuel Gas and Fuel Oil.
One guest suggest us to burn both Fuel Gas...
We have a Vacuum Distillation Unit in our refinery.
The operating temperature of the Vacuum Residue(Asphalt) pump is 350C.
The mechanical seal plan of the Vacuum Residue pump is:
Plan 32 with Seal Fluid: HVGO(Heavy Vaccum Gas Oil)
+ 52 with Seal Fluid: Synthetic Lub. Oil
As the seal...
We produce a penetration grade Asphalt from a Vacuum Distillation Unit(without Air Blowing) in our refinery.
The penetration of our Asphalt is 50~100.
Our customer claim that although our product meet the penetration specification of Asphalt, the Aging test show that our product has a higher...
I have heard that it is dangerous to do online spalling of furnace tube for Delayed Coker Plant in the refinery.
The reason is that there is a common convection section in the Coking Heater.
When one flow pass is under online spalling, the other flow pass is still running at its normal...
We have a Vacuum Distillation Plant in our refinery.
The seal plan 32 is used for the bottom(Asphalt) pump of the distillation column.
Because some gas oil is injected to the process fluid in this pump. This may affect the quality of the final product Asphalt.
Is there any better seal plan in...
The TGTU of our sulfur plant include a hydrogenation reactor and MDEA absorption and regeneration.
We encounter serious fouling problem in the lean/rich amine heat exchanger.
We have to shut down the unit for cleaning the heat exchanger every 3~4 months.
Is this a normal situation?
Do we...
We have a sulfur plant designed to process the sour gas from the hydrotreating unit.
It is a claus reactor with TGTU.
We find the reliability of the system is not so good, especially the TGTU.
Our refinery is located very close to the local resident.
Do we need a spare sulfur plant?
What is...
In our sulfur plant, we have a sulfur degasser to remove the H2S in the product sulfur to 5ppm.
We frequently encounter liquid sulfur carryover to the downstream thermal oxidizer which cause a serius environmental problem.
We install two level switchs(High and High High level) in this column...
We use flush plan 54 for our heavy oil(Atmospheric Residue)
pump in the refinery.
The operating temperature is 340C.
We use dual mechanical seal in this service.
We encounter seal leakage problem very often.
Is there any better flush plan in this service?
We encounter a dangerous fire in our refinery recently.
The direct cause is the failure of the pump mechanical seal which cause the crude oil to leak.
After the fire, when we check the bearing, we find that pump bearing(ball type) also is damaged.
The bearing balls are no loner spherical and...
We have a sour water stripper unit in our refinery.
The design of the stripper is as follows:
1.There is no overhead condenser and receiver.
2.There is a pump-around section for heat removal in the column upper section.
The designer state it is because ammonium salt may precipitate in the...
We have a naphtha splitter in our refinery.
The splitter separate naphtha into light and medium naphtha.
Recently we encounter leakage of the reboiler in this splitter.The steam then enter this column and contaminate the light naphtha with water.
We want to know the root cause of the...
I am not familiar with mono-pump.
I want to know its major application, especially its advantage and disadvantage.
We have a process stream which contain 10% of petroleum coke and balance water.
The petroleum coke is sand-like material, its viscosity is low.
I do not know if it is feasible...
We have a big sulfur plant with capacity of 500ton sulfur/day.
We have a long term struggle with the on-line H2S/SO2 analyzer.
Is there any expert can teach us how to maintain this instrument?
There is a tank(15m height) that is always overflowing during normal operation.
We plan to add a pump to pressurize the overflow stream so that it can be sent to a downstream hydrocyclone for particle separation.
We do not want to add a surge tank in between the tank and the pump for saving...
There is a De-NOx reactor in our CDU(Crude Distillation Unit) heater system.
The effluent gas from the heater enter this reactor.
It is a selective catalytic reactor with ammonia injection.
From time to time. we encounter high pressure drop in the reactor. Especially when this plant start up...
