Solid carbonaceous feed

Coking processes have the virtue of eliminating the residue fraction of the feed, at the cost of forming a solid carbonaceous product. The yield of coke in a given coking process tends to be proportional to the carbon residue content of the feed (measured as the Conradson carbon residue see Chapter 2). The data (Table 7-11) illustrate how the yield of coke from delayed and fluid coking varies with Conradson carbon residue of the feed. 

Figure 6.11 shows the product yields for each catalyst. The products are classified into four lumps, i.e. gas (carbon number 1-4), gasoline (5-11), heavy oil (above 12), and a carbonaceous residue referred to as coke. In the figure, PE oil represents the feed oil and contains a 34% gasoline fraction. The feed oil was effectively cracked by solid acid catalysts. The gasoline yield was highest with REY zeolite. HZSM-5(65) yielded the... 

A bank of four horizontal stirred beds is used, one above another, of the screw conveyor type. The top one is for calcination in air to remove traces of nitric acid, water and carbonaceous products, the middle two for hydrofluorination and the lower one mainly for partial sintering and den-sification of the product in hydrogen fluoride. Each stirred bed reactor is 20 ft long and 16 in. internal diameter, the lower ones made of inconel and the upper one of stainless-steel. The powder flows from a hopper at the top, via a seal hopper between the calcination and hydrofluorination sections, to another hopper and feeding system at the bottom, as shown in Fig. 5.8. Air and anhydrous hydrogen fluoride pass in counter-current flow to the solids in the appropriate reactors, the efBuent gases being conducted to suitable filters and dust collectors. 

The very high yields of carbonaceous solids and the low metal contents obtained when the electrical discharge is established into a heavy hydrocarbon exclude the generation of a catalyst precursor directly in the feeding line of a hydroconversion reactor it would produce an excessive amount of carbonaceous solids. It must be kept in mind that the catalyst is destined to conversion of residues, therefore the introduction of excessive amount of useless material must be kept to a minimum. 

Chlorinated hydrocarbon liquid streams from the oxychlorination process (this chapter), containing flnely divided carbonaceous solids and metallic corrosion products in solution and suspension are pumped into the lower portion of the fluidized bed. Air is used to fluidize the bed and to oxidize the feed. The reaction occurs at below 540° C. Combustion of the feed is essentially complete with no significant breakthrough of elemental chlorine and only minor breakthrough of chlorinated hydrocarbons (Benson, 1979). The heat of combustion is recovered by generating medium to high pressure steam inside coils placed in the bed. The pro-... 

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