Catalyst performance testing feedstock

Table 41.3 shows a performance comparison of Pt/Pd TUD-1 with a commercial Pt/Pd catalyst (26). The feedstock is a typical straight run gasoil ( SRGO ), a distillate precursor to diesel fuel. Under identical test conditions, the TUD-1 catalyst achieved 75% aromatics saturation versus 50% for the same volume of commercial catalyst. This superior result is particularly interesting because the TUD-1 catalyst had a much lower density than the commercial material, so that less catalyst by weight was required in the reactor. 

The asphaltenes are selectively converted with a low hydrogen consumption decreasing significantly the metal content in the product. Catalyst was tested during a six-month period, processing various heavy feedstocks and showing a stable performance. The yields and product quality reported indicated almost complete conversion of the feed and total metal removal. The net effect of the ABC pretreatment was found to be an increase in catalyst life, higher metal quality of the product oil, and increase distillate yields. 

This coke has been related with feedstocks quality and more specifically with their carbon Conradson content. The catalyst used for this analysis was the sample without metals deactivated 20 hours, 30 cycles, and 80% steam. The MAT test was performed with feedstock of different quality gasoil, DMO, and mixture of gasoil-DMO. 

A great need exists for reliable Fluid Catalytic Cracking performance tests which can be used for the evaluation of feedstocks and catalysts. 

Tests on several feedstocks were performed with the CoMo-C and CoMo-D catalysts. These tests were carried out for over 1000 hours, i.e. about one month and an half During testing, the reactor temperature (the main parameter that causes the catalyst ageing) was ramped from 325°C to 360°C with an average temperature higher than 340°C. At the end of the tests, the operating conditions were returned to the initial values in order to estimate catalyst deactivation. 

Extensive performance testing has been carried out in pilot plants to determine the optimum process conditions, catalyst stability and product properties. A range of vegetable oils have been processed in the pilot plants, including soybean, rapeseed, palm and jatropha oil. Other potential feedstocks, including tallow and greases derived from animals, have been evaluated. 

A great need exists for reliable FCC performance tests which can be used for the evaluation of feedstocks and catalysts (O Connor and Hartkamp, 1988 Mitchell and Moore, 1988). With the hundreds of catalyst variations available the choice of a suitable catalyst becomes complex and... 

Stability tests of catalyst. All catalysts deactivate during their life by various causes (see Chapter 3). The aim of stability tests is to examine the cause and rate of deactivation. These experiments are usually performed at conditions similar to those planned for the commercial unit. In some cases, accelerated tests are carried out using a feedstock with an elevated level of impurities or at a temperature significantly higher than that anticipated for the full-scale reactor. A laboratory reactor used for such tests is usually a down-scaled reactor or a part of the full-scale-reactor. Standard analytical equipment is used. 

The C-5 sugar alcohols produced from the hydrolysis of hemicellulose are both xylitol and arabitol [6], Equivalence testing was performed with Ni/Re catalyst in the batch reactor to verily similar performance between xylitol and arabitol feedstocks. The operating conditions were 200°C and 8300kPa H2 using the procedure outlined in section Catalyst Screening section. 

Arabitol testing was performed to ensure that it behaved similarly to xylitol in this reaction to validate xylitol as a model compound. Testing was performed using Ni/Re catalyst from the initial batch screening. Shown in Table 1, the results from the two sugar alcohols were nearly equivalent. This gave some confidence that xylitol should be a valid model compound in the absence of actual hemicellulose derived feedstock. 

This type of coke depends exclnsively on the FCC cracking activity. In order to have samples with different activity and little inflnence of contaminant coke, the fresh catalyst was deactivated hydrothermally at different severity conditions withont metals. MAT test for these deactivated samples was performed with VGO as a feedstock to diminish coke yields. 

Potential pitfalls exist in ranking catalysts based solely on correlations of laboratory tests (MAT or FFB) to riser performance when catalysts decay at significantly different rates. Weekman first pointed out the erroneous conversion ranking of decaying catalysts in fixed bed and moving bed isothermal reactors (1-3). Phenomena such as axial dispersion in the FFB reactor, the nonisothermal nature of the MAT test, and feedstock differences further complicate the catalyst characterization. In addition, differences between REY, USY and RE-USY catalyst types exist due to differences in coke deactivation rates, heats of reaction, activation energies and intrinsic activities. 

Spent catalyst samples were collected from benchscate runs with Arabian heavy vacuum gas oil (VGO) or Kuwait atmospheric resid, For the VGO samples, the conditions of these runs were P = 50 atm., LHSV = 2.0 h 1, T = 375°C, run length approx. 500 hours. The testing of the resid samples was performed at P = 123 atm., LHSV = 0,25 h 1, T -407°C and a run length of 7500 hm. The catalysts were presulfided for 24 hours at 350°C and 100 aim. using the VGO, After presulfiding and introduction of test conditions, the feedstock was introduced. 

The on-going research at the Center for Applied Energy Research in the preparation, characterization and activity testing of these catalysts has produced a number of continuous plug-flow and trickle bed reactor runs of 20 to over 600 hours duration using different hydrocarbon feedstocks. At the completion of experiments in which the activity, defined by conversion of the feedstock, has declined, experiments to determined if the acid and/or metal function was responsible for the observed deactivation were performed. The results of these experiments are reported below. 

Conclusions. It is necessary to test a catalyst s stabihty and performance under high vanadium conditions for materials which will be processing metals laden feedstocks. The Engelhard Transfer Method offers the benefits of both the Mitchell Method and... 

Ibs/ft hr (0.10 kg/m s) in minimum as liquid mass velocity utilized in a pilot plant test and a correction method involving mainly effects of feedstock properties on desulfurization activity are proposed to get better agreement in evaluating aging performance and cycle length of a catalyst system with multiple catalysts between pilot and commercial units. 

Since different origins of resid feedstock are hydrotreated in the commercial fixed bed unit, an issue how to correct the commercial result is raised to compare them with pilot test results. The difference in the liquid mass velocity and the oil distributor efficiency between the pilot and commercial units is another important issue for determining the correlation between both units. The performance of catalyst was, therefore, evaluated under the normalized conditions applicable to the results of both units. 

Discrepancies in catalyst aging performance between laboratory tests and commercial units are often observed. Different liquid mass velocity and/or type of feedstock can be reasons for the discrepancies. 

The INT-RI catalyst can be used in fixed bed hydrotreating units to improve the residue quality, from a high sulfur residual to a low sulfur fuel oil [6]. Tests were performed to demonstrate the technical feasibility of directly processing these residues, using atmospheric residue of Cerro Negro and Iranian Gach Saran crude oils as feedstocks. These residues are characterized by a higher content of asphaltenes and Conradson Carbon than the deasphalted oils [5,6]. Therefore, the effect of these two variables on the performance of the catalyst, can be evaluated. 

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