Environmental Engineering Reference
In-Depth Information
Heat Integration in Crude Atmospheric Distillation Unit
In crude atmospheric distillation units, feed get separated to different cuts according to
difference in boiling points. Crude feed get heated up from the ambient temperature to the
desalting temperature, normally between 126 and 140 ºC. After desalting operation that
reduces the crude temperature between 3 to 6 ºC, crude is fed to the pre-flash drum or
sometimes even tower to remove some of the light hydrocarbons before the crude goes to the
crude furnace.
Petroleum Gas & Light Naphtha
~40°C
Distillation
tower
Crude oil
feed
Heavy Naphtha
~25-175°C
Kerosene
~150-260°C
Fired
heater
~235-360°C
Light Gas Oil (LGO)
~350-
370°C
~330-380°C
Heavy Gas Oil (HGO)
Atmospheric residue
Preheated Crude oil
~250-280°C
Figure 9. Crude Atmospheric Distillation Unit
As shown in the generic crude atmospheric distillation; Figure 9 above the products from
the crude tower and circulating pump-around that are used as tower inter-coolers are used to
aid the products in heating the incoming crude. The incoming crude then is fed to the heater
to raise its temperature to the desired flash zone temperature in the atmospheric distillation
column.
It is always of high importance in the design of this unit to integrate the cold stream
represented by the crude feed stream and products as well as pump-arounds to reduce the heat
load the crude heater as much as possible. In this chapter, a real industrial application is
introduced and discussed.
Table 2 below, shows data extracted from plant process flow diagrams for the crude as a
cold stream and other hot streams. The cold stream is segmented into several streams using its
simulation heating curve to avoid in-accuracy for assuming constant specific heat along long
temperature range. The same is also practiced for some hot streams as shown in the table,
using its simulation cooling curves.
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