Real feeds

The affinity of AC for the adsorption of asphaltenes from VR at 523 K and 10 MPa of H2 was dependent on the mesoporosity of AC. Among three AC studied, the one possessing the greatest mesoporosity was the most efficient. The same AC was the best support for the Fe/AC catalyst used for hydroprocessing the VR. This catalyst exhibited the highest activity for asphaltenes conversion. 

The VR derived from Athabasca bitumen was upgraded in supercritical hydrocarbon solvents (pentane, heptane and toluene) over AC at 643 K and 10 MPa of H2 by Xu et Under these conditions, a large conversion of 

An unusual feed obtained by pyrolysis of scrap tires was tested by Ucar et At 623 K and 7 MPa of H2, the AC was active for HDS and HCR. However, the activity was significantly enhanced after the addition of active metals to the AC. 

---

Model compound studies that are calibrated with physical studies and connected to real feed studies. 

In competitive demetallation experiments the same rates do not necessarily hold. Hung and Wei (1980) reported that with both Ni-etio and VO-etio in the feed, the vanadium removal rate was the same as in the individual vanadium run, whereas the nickel removal rate was suppressed to below that of vanadium removal. In a related study using a mixed Ni-T3MPP and VO-etio oil, Webster (1984) reported that VO-etio de-metallated faster than Ni-TMPP and also suppressed the metal removal rate of the latter. This inhibition phenomenon offers a partial explanation as to why in most commercial operations with real feeds vanadium is more reactive than nickel. 

Life studies are intended to test the catalysts during a longer time on stream, often on a bench or pilot scale with real feeds and recycle streams. The latter allow investigation of the effect of trace impurities or accumulated components, not observed in laboratory-scale experiments. Often, it is desired to test the catalyst at the same time in its shape for practical application. Here, the need exists for experimental results that can be directly linked to commercial applications. 

Initial Coking and Deactivation of Hydrotreating Catalysis by Real Feeds P. Wiwel, P, Zeuthen and A, C. Jacobsen... 

INITIAL COKING AND DEACTlVAnON OF HYDROTREATING CATALYSTS BY REAL FEEDS... 

Practical activities are used when catalyst comparisons only are required. Measurements are faster and less demanding. The same types of reactor discussed above are used or larger units may be required. The principal function of pilot unit operations is to explore real feeds, process conditions, and deactivation, but practical activities are usually measured as these change. Three types are encountered measurement of (1) conversion at fixed space velocity, (2) space velocity for a fixed conversion, and (3) temperature for a fixed conversion. 

Initial Coking and Deactivation of Hydrotreating Catalysis by Real Feeds... 

When analyzing the performance of a real column, the switch from one operating line to another must be made at a real feed plate. Because of changes... 

In actual operation with a real feed, the membrane resistance may be only a small part of the total resistance. Other resistances can be added to the intrinsic membrane resistance ... 

In a simulation problem the column has already been built, and we want to know how much separation can be obtained. As noted in Tables 3-1 and 3-3. the real number of stages, the real feed location, the column diameter, and the types and sizes of reboiler and condenser are known. The engineer does the detailed stage-by-stage calculation and the detailed diameter calculation, and finally he or she checks that... 

Although the primary focus of this review was carbon and carbon-supported catalysts, attempts have been made to identify the difference in the effect of carbon supports compared with the oxidic supports, particularly that of y-Al203. It has been noted that many studies had the same objective. For this purpose, the difference in catalyst activity and stability was estimated using both model compounds and real feeds under variable conditions. The conditions applied during the preparation of carbon-supported catalysts have... 

Both model compound mixtures and real feeds have been used for determining catalyst activity. Among the latter, the feeds of petroleum origin, coal-deiived liquids (CDL) and biofeeds have received attention. From the practical applications point of view, the results obtained using real feeds provide a more realistic picture on the performance of catalysts than those obtained using model compounds. For example, the effect of pore-size and pore-volume distribution on catalyst performance may not be accurately identified using model feeds. 

Most of the studies on catalytic activity of the 1st, 2nd and 3rd TMS supported on carbon have been using various model compounds, although to a lesser extent real feeds have also been included in the studies. In this case, the Fe supported on AC have attracted some attention. In recent years, the carbon-supported metal carbides, nitrides and phosphides were also tested as catalysts for hydroprocessing reactions. 

Noble metals (NM) supported on carbons have been tested as catalysts for various model reactions, as well as for real feeds. In this regard, HDS, HDN, HCR and HDO activities were determined. In similar reactions, metal carbides, metal nitrides and metal phosphides supported on various forms of carbon have also been receiving attention. 

With respect to the HDN of real feeds, refractory N-containing heterorings such as carbazole and acridine, as well as their alkylated analogues have been studied extensively. However, all information includes catalysts supported... 

There is a wealth of information on HDM reactions involving model compounds such V- and Ni-containing porphyrins, as well as real feeds." However, a predominant part of this database involves the catalysts supported on y-Al203 and other metal-oxide supports. The reaction network for the HDM of metal tetraphenyl porphyrins (MTPP) developed by Janssens et is shown in Figure 57. This is among the most detailed networks... 

Information on the hydroprocessing catalysts supported on carbon materials in the patent literature is rather limited. This contrasts with a large number of patents on other carbon-supported catalysts, i.e. automotive, HYD for chemicals production, etc. In most cases, the disclosures of the carbon-supported hydroprocessing catalysts considered real feeds. 

---