Capacity of Oil Heater?

Irrespective of the capacity of the heater, how is it proposed to install the heater while the tank is filled with 34000m³ of crude oil?

as i understand you ask if the heater is vertical or horizontal??

i prefer the vertical type

How is it proposed to install the heater while the tank is filled with 34000m³ of crude oil?

How fast do you need to do this?

What heat sources are available? These might include steam, electrical heaters, direct-fired combustion, etc. Or hot water, if you have a geothermal source. Of these, I suspect steam is the most common, but this is not at all certain.

it will be direct fired combustion. About the time, we don't care very much about it

You must be careful that the oil does not become too hot, which would degrade it. (I'm not sure of the best term, but have heard of "coking" or "carbonization.") Hot water or steam can be easily regulated to prevent this, but with direct combustion, you will need to have positive oil circulation through the heater; probably a pump, and also a way to shut down the heater if the pump fails. This is doable, but it is late in my time zone, and I need to think about it some more. I will try to return and add more detail.

Coking and carbonisation are a definite problem with direct-fired heating unless a high flow rate is maintained. With -10°C waxing is going to be a major setback to initial circulation.

To be honest I can see you having major problems with any form of direct heating. I personally would look at indirect heating via steam heating coils in tank.

Watt required = {(mass of crude oil x specific heat of crude + mass of tank x specific haet of tank material) x (Rise in temp required X 4180)}/ Time requirement for temp rise in sec

You can factor in effiiency depending on the design of system.

And the tank surface losses? The OP has not given a jot of information about the tank, its materials of construction, its shape, what it's standing on, its insulation and the ambiant temperature at the location!

HI PWS.

of course OP has not given those informations But that doesn't means the formula provided is invalid, All those variables are already covered in last sentence of my post where it talks about efficiency, Its for OP if he want to make an insulated tank or a bare one, If he choose the later then efficiency will be low,It is just a formula and OP must know what efficiency he is going to achieve and how he is going to achieve,

No offence taken anyway, sorry if there is something that I missread.

No offence taken here.

In the asphalt business liquid asphalt is heated to a constant temperature of 400 F, using a #2 fuel oil circulatory system. We do the same thing with the fuels we use to run our dryers. We usually use #5 or #6 oil or even WDLF (waste derived liquid fuel) as a fuel for our dryers; to keep them at a heated temperature around 250 F we use a similar technique as stated above. The manufacturer of our heating system uses the same formula you gave. Thanks.

I am currently working on a project to rebuild a hot melt asphalt plant, and we are using hot thermal oil to heat the asphalt storage tanks, mixing vessels and pipelines.

We have two systems, one is a gas-fired heater and the smaller systems are electrically heated. In both cases we are using a thermal oil with a high flash point at a temperature of 400 deg F. Temperature control in the tanks and vessels is the same concept: temperature is monitored and thermal oil is directed to the vessel coils or jackets when heating is needed, or directed to bypass the vessels and return to the thermal oil recirc piping when product temperature is within process limits.

You are correct, it is cheaper to keep the asphalt and thermal oil at temperature rather than constantly heat, cool and re-heat them.

It would be cheaper to keep the oil at ambient and heat it wherever, whenever and to whatever temperature it is needed.

In the asphalt business our heaters are run 24/7 as long as the plant is running (usually 9-10 months a year), because it takes to long to increase the heat of the oil's to your desired temperature. When your dealing with more viscus oils like liquid asphalt, #5, #6, crude oil, bunker oil, etc. It takes alot of initial energy to bring that oil to temperature. It's easier and more efficient to bring it there and keep it.

With PW, I agree that you don't need to heat the whole tank. Rakesh has given a good formula. You can heat the subsection of your tank that feeds the oil to where it is needed. To avoid localized overheating of the oil (the "coking"/carbonization that has been mentioned), the heating elements, whether hot water or steam coils or electrical, should be of ample surface area to transmit the required heat without being very hot themselves. As a rough guess, maybe the oil to your process needs to be about 80°C, but the heating coils or elements are held to 90°C or less to keep from damaging the oil. This is just an example, because I don't know the limitations. Whatever they may be, in this example the heating coil/element would be sized to transfer the required heat with a 10°C (90-80) TD (temperature difference).