Examples hydrocarbon stripper

As discussed in Chapter 1, a portion of the feed is converted to coke in the reactor. This coke is carried into the regenerator with the spent catalyst. The combustion of the coke produces H2O, CO, CO, SO2, and traces of NOx. To determine coke yield, the amount of dry air to the regenerator and the analysis of flue gas are needed. It is essential to have an accurate analysis of the flue gas. The hydrogen content of coke relates to the amount of hydrocarbon vapors carried over with the spent catalyst into the regenerator, and is an indication of the rcactor-stripper performance. Example 5-1 shows a step-by-step cal culation of the coke yield. 

As shown in Fig. 18.23, dry liquid feed containing olefins and isobutane is charged to a combined reactor-settler. In this example, the reactor uses the principle of a differential gravity head to circulate through a cooler before contacting a highly dispersed hydrocarbon feed in the reactor pipe. The hydrocarbon phase, generated in the settler, is sent to a fractionator, which separates LPG-quality propane, isobutane recycle, n-butane, and alkylate products. A small amount of dissolved catalyst is also removed from the propane product by a small stripper tower. 

Methane is the most common hydrocarbon in acid gas mixtures. Large quantities of other hydrocarbons are probably indicative of problems with the amine plant and should be addressed. For example, foaming will cause carry-over of the hydrocarbons into the stripper. In the regeneration of the amine, the hydrocarbons will end up in the acid gas. 

The process concept involves the extraction of light hydrocarbon oils from asphaltic petroleum supercritical solvents followed by a subsequent fractionation and separation of the oil from the solvent. It is stated that the metal compounds which are present in the asphaltic petroleum do not dissolve in the solvent under the conditions of operation. The primary difference claimed for this new process relative to the old processes is that the solvent is at or above the critical temperature rather than below the critical temperature as is described in prior art. The operation is explained in the patent with the aid of a simple distillation-like extraction vessel. Asphaltic feedstock is heated and introduced into the extraction vessel. The solvent is also heated and introduced into the vessel and the two streams are mixed. The temperature is maintained at or above the critical temperature of the solvent. In the extractor, the non-soluble components of the feed setde and are removed and sent to a stripper to recover and recycle the solvent. Several examples give quantitative information when an asphaltic feedstock containing 28 ppm Ni, 220 ppm V is used. The oil yield and metal content results are given below for two cases where the solvent is catalytic cracker gasoline and propane, resf>ectively. 

Solvent loss elsewhere] upstream units, for example for glycol dehydration glycol dumped with hydrocarbons separated in upstream flash drum/loss in downstream solvent stripper. 

The hydrocarbon which is to be revaporized in the product stripper falls to the draw tray as part of the internal reflux from Tray (D1 + 1) rather than rising to the tray as part of the product vapors. In passing across the draw tray, this liquid absorbs a small amount of the reflux heat. This heat absorption is calculated as LSVr example calculations that this... 

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