Typical refinery process flow

Liberated gasses are drawn off at the top of the tower with the naptha. The gas is recovered to manufacture refrigerated liquefied petroleum gas (LPG). The naptha is condensed at a temperature of about 52 °C (125 °F). Part of the condensed naptha is normally returned to the top of the tower. The naptha product stream is split into light naptha for gasoline blending and heavy naptha for further reforming. Inside the tower, kerosene is withdrawn at a temperature of about 149 °C (300 °F). Diesel is withdrawn at a temperature of 260 °C (500 °F). These middle distillates are usually brought up to specification with respect to sulfur content with hydrodesulfurization. The heavy oil 

After products are produced by refining they are further enhanced in a blending unit. In this unit the finished products are made by mixing the components in blending tanks. To gasoline for example, coloring dyes or special additives maybe added. The completed blends are tested and then routed to tank farm storage or shipment. 

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The gasoline Molex process is the first of three processes since it separates the lowest molecular weight feed of the three Molex normal paraffin separahon processes. Gasoline Molex was developed to optimize a Refiner s octane pool by extracting low octane value normal paraffins (specifically C5, 5) from naphtha. In a typical refinery flow scheme, a gasoline Molex unit is integrated with a catalyhc isomeriza-hon unit (Penex unit) which converts the Molex unit s extracted normal paraffins into desired iso-paraffins. These iso-paraffins are desirable because they possess higher octane value than their linear counterpart. 

The sources of wastewater generation in petroleum refineries have been discussed previously in this chapter. Table 5 presents a qualitative evaluation of wastewater flow and characteristics by fundamental refinery processes [5]. The trend of the industry has been to reduce wastewater production by improving the management of the wastewater systems. Table 6 shows waste-water loadings and volumes per unit fundamental process throughput in older, typical, and newer technologies [15]. Table 7 shows typical wastewater characteristics associated with several refinery processes [16]. 

Aerobic Treatment Process. Effluent from edible oil refineries has been shown to be amenable to biological treatment, both anaerobic and aerobic processes (74,75). The application of activated sludge process or aerated lagoon in this context is well established in the edible oil industry (71, 73, 76). Figure 14 shows the process flow of a typical activated sludge process. 

Figure 1.6 indicates where a lubricant base oil plant fits into the process flow scheme of a typical refinery - if ever there is such a thing. Although the scheme is simplified, the inter-relationship between the base oil plant and other process units and product streams is evident. In a sense, the base oil plant and the fuel-upgrading plant, such as the catalytic cracker, compete for feedstock from vacuum distillation. These interactions are very important to the logistics and production economics of producing base oils. 

The economics of VRD favors separations involving components with similar boiling points (e.g., the separation of propane and propylene in an oil refinery, in a column that is typically referred to as a C3 splitter ) so that the temperatures of the top and bottom streams of the distillation column are close. This reduces the power consumption of the compressor as well as the duty (and associated heat-transfer area) of the trim condenser. Given the above, we can make the following observations and assumptions concerning the various steady-state energy flows in the process. 

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