Cracking hydro

Process Atmospheric distillation Atmospheric distillation FCC Hydro- cracking Vis- breaking Coking Hydrocracking... 

Gas-to-liquids (GTL) is the chemical conversion of natural gas into petroleum products. Gas-to-liquid plants use Fischer-Tropsch technology, which first converts natural gas into a synthesis gas, which is then fed into the Fischer-Tropsch reactor in the presence of a catalyst, producing a paraffin wax that is hydro-cracked to products (see also Chapter 7). Distillate is the primary product, ranging from 50% to 70% of the total yield. 

Consecutively, the heavy paraffins are cracked into lighter hydrocarbon fractions by hydro-cracking. For example, for the Shell Middle Distillate Synthesis (SMDS) process, the liquid product stream is composed of 60% gasoil (diesel), 25% kerosene and 15% naphtha. The gaseous product mainly consists of LPG (a mixture of propane and butane) (Eilers et al., 1990). Figure 7.3 shows a simplified diagram comprising all process steps to produce synthetic hydrocarbons from biomass, natural gas and coal. 

The process of hydro-cracking was already developed in 1927 by the German company I. G. Farben Industrie, to transform lignite into gasoline. As a support for thermal or catalytic cracking, hydro-cracking is used nowadays to crack hydrocarbons that are more difficult to crack. 

A number of refinery processes require the use of a fixed-bed catalyst These processes include catalytic reforming, hydrodesulfurization, hydrotreating, hydro-cracking, and others. These catalysts become inactive in six months to three years and are eventually replaced in the reactors with fresh catalyst during a unit shutdown. Many of these catalysts contain valuable metals which can be recovered economically. Some of these metals, such as platinum and palladium, represent the active catalytic component other metals such as nickel and vanadium are contaminants in the feed which are deposited on the catalyst during use. After valuable metals are recovered (a service usually performed by the outside companies), the residuals are expected to be disposed of as solid waste. 

It is significant that the mixture yielded propane as the major product (Table III). As noted in our earlier paper on catalytic cracking (6), the predominance of C3 fragments in the cracked products and the absence of isobutane appeared to be a unique property of erionite. Our present data indicate that this is also true for hydrocracking over a dual function erionite. The only exception was that when n-pentane alone was hydro-cracked, equimolal quantities of ethane and propane were found. This shift in product distribution in the presence of n-hexane, a second crackable component, indicated that the reaction path within the intracrystalline space was complicated. 

In Situ Hydro-cracked Truck-Tractor Diesel (6)... 

Fig. 18.28. Two-staged, partial-conversion hydro cracking process.25 (Copyright 1999 by Gulf Publishing Co. and reprinted by permission of the copyright owner. All rights reserved.)...

E. Hakejova et al. [12], studied the pyrolysis of individual hydrocarbons, and of naphtha, kerosene, gas oil, and hydro-cracking fractions, as well as their copyrolysis with hex-adecane, heptane, iso-octane, cyclohexane, and also with heavier feedstocks, i.e. dewaxing... 

Recycled Through Hydro- cracking RT Conversion to Olefins (wt °/o)... 

Carbon number of alkanes formed by hydro cracking... 

The Fig. 15 indicates the change in the number of species generated (paraffins, olefins, ions, in Fig. 15a) and the number of reactions (hydrogenations, pro-tonations, HS, MS, ethyl shiftes (ES), PCP branching, PCB branching, beta scissions, in Fig. 15b) according to the number of carbons of a single hydro-cracked normal paraffin. 

L. Z. Pillon, Use of UV Spectroscopy to Predict the Daylight Stability of Hydro-cracked Base Stocks, Petroleum Science and Technology 19(9—10) 1263—1271 (2001). 

Application To produce polymer-grade ethylene and propylene by thermally cracking hydrocarbon feedstocks (ethane through hydro-cracked residue). Shaw s key process technologies are ... 

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