7 replies to this topic

[Tamizh]

hi all... I am designing crude oil heater. am using hot oil as a heating medium. The pressure of hot oil is greater than my working fluid. which side i have to pass? i studied that high pressure fluid should pass on the tube side and high viscosity fluid should pass on the shell side..... 

[Robert74]

Dear Sir

It is better to place the DIRTY fluid inside tubes. This is because it will facilitate the cleaning. Cleaning tubes is much easier than cleaning shell side. Therefore I suggest to place Crude Oil in tube side and the thermal oil in the shell side. Tubes shall be 1" (25.4 mm) size in order to be cleaned easily.

For Pressure, I suggest thermal oil pressure to be higher because leaking of thermal oil to crude oil stream is better than the opposite situation.

Generally, heating crude oil for atmospheric distillation system is done using "Fired Heater" instead of using thermal oil boiler and heat exchanger. If you have reliable source for this idea please share it.

 

Robert

[srfish]

I agree with Robert74 that the dirty fluid (Crude Oil) should be in the tube-side. That is if the Crude Oil is truly dirty. It would help to know how foul the Crude Oil is. If it is relativity clean ( fouling factor 0.002) then an AEU heat exchanger could be used with the Crude in the shell. Otherwise at higher fouling factors, use an AES type with the Crude inside the tubes. 

[Robert74]

Dear Mr. Srfish,

You are right. Anyway, crude is considered dirty while thermal oil is pure clean. Hence cleaning tube is much easier.

I am still thinking of heating crude oil using thermal oil instead of Fired Heater, where direct heating can be achieved instead of paying more for thermal oil heating network and pumps.

 

Regards,

Robert

[sukanta87]

Hi Robert,

Presently the thermal oil system is getting popularity for heating purposes. If we consider heating crude oil, the heating by direct fired heater is enough non-linear which may cause thermal shocking of the materials and coke formation in the oil. Abruptly process conditions changed by direct fired heater specially in time of plant shutdown. To recover the scenario, thermal oil heater (TOH) is used. The main advantages of TOH is it gradually increases/decreases the process oil temperature in time of operation or shutdown. If a plant goes for short time shutdown like 3-4 hours and then again start up, TOH facilitated plant can sense little changes (specially the different process temperatures). But a plant facilitated with direct fired heater faces an abrupt change in the whole processes as the temperature dropped suddenly.

But, yes you are right about the costing and complexity of TOH. The thermal oil is also very hazardous.

[Robert74]

Thank you Mr. Sukanta,

From my own point of view, fired heater usage is superior to thermal oil heater because

1. Thermal oil shall be changed after a specific usage

2. Thermal oil flow rate is high compared to the heated crude oil flow

3. Large flow rate makes more expensive heating system with many equipment specially the large High Temperature pump. On the other side, the smaller crude pump is operating in a normal temperature.

4. Coking problem in fired heater can be overcame be proper design specially by reducing heat flux value

 

Regards,

Robert

[S.AHMAD]

Dear All

1. What important in crude oil refining is economics and we always use LP to optimise operations and production.

2. Therefore, profit matgins is prime important in crude refining. In some situations of market, crude oil refining profit margin is sometimes (or most if the time?) very thin.

3. Thus, with higher investment cost and operating cost of hot oil generation facility, I have some doubt whether the operation is economical. Has anyone done any economic of this option?

[maqqadri]

your discussion helped me somehow.
kindly help me further if I modify gas WBH@4.8MBtu/hr into side steam crude heater
1) is it possible
2) what can I do if any modification is required
3) can I utilize TEG in place of water as heating media