Liquid Space Velocity Research Articles

Effects of parameters in Ni–Mo catalysed hydrocracking of vacuum residue on composition and quality of obtained products

The laboratory findings were presented for a single-stage hydrocracking process of vacuum residue (VR) of Ural crude. The Ni–Mo/Al 2O 3 catalyst in suspension was used in tests. The amounts and quality of the obtained products were related to process parameters. Hydrocracking of VR was carried out in a continuous flow reactor, at the temperature of 410–450 °C and pressure of 12–20 MPa, at the liquid space velocity (LHSV) of 0.25–0.75 h − 1 , and at the gas space velocity of 2500 h − 1 . The studied catalyst Ni–Mo/Al 2O 3 was found moderately active in the VR cracking process, while it turned out an efficient catalyst for the hydrofining processes. The catalyst concentration and hydrogen pressure had no effect on hydrocracking of VR, and hydrofining of cracking products was affected slightly only over the studied scope of parameters. The reaction temperature and LHSV exerted dramatic effects on hydrocracking of VR and on the asphaltenes and CCR contents, while their effect on hydrofining of cracking products was much lower. The temperature of 430 °C resulted in VR conversion to distillates (b.p. < 538 °C) of 61.6–88.7 wt.% and in sulphur conversion of 70–85 wt.%.

Study on single-stage hydrocracking of vacuum residue in the suspension of Ni–Mo catalyst

Activity of the Ni–Mo/Al 2O 3 catalyst was studied in a single-stage hydrocracking process of vacuum residue (VR) of Ural crude. The process was carried out in a continuous flow reactor, at the temperature of 410–450 °C, at the pressure of 12–20 MPa, at the liquid space velocity of 0.25–0.75 h −1 and at the gas space velocity of 2500 h −1, and a suspension of the catalyst tested was used. The catalyst was found efficient for the hydrogenation processes, inclusive of hydrodesulphurisation processes, but its cracking activity was moderate. The catalyst concentration and hydrogen pressure did not affect significantly the VR hydrocracking process over the studied scope of parameters, and only some small effect was noticed on hydrodesulphurisation of the cracking products. On the other hand, the reaction temperature and LHSV were found to strongly affect the VR hydrocracking process and to reduce the contents of asphaltenes and CCR, while the impact on hydrodesulphurisation was lower. The reaction rates and activation energy values were determined for those reactions. The conversion figure for VR to distillates (bp < 538 °C) reached 61.6–88.7 wt.% at 430 °C, and sulphur was converted at 70–85 wt.%.

Selective Hydrogenation Catalyst of Ni-Mg/Al2O3 for FCC Light Gasoline

A catalyst is provided for the selective hydrogenation of dienes from fluid catalytic cracking gasoline. There are a small quantity of dienes in fluid catalytic cracking gasoline which can deteriorate the quality of fluid catalytic cracking gasoline, as well as make its further process inconvenient. These dienes must be reduced as impurity. In this paper, the nickel supported on alumina selective hydrogenation catalysts modified with magnesium promoter are prepared by impregnation method. The fluid catalytic cracking gasoline (<75°C fraction) is observed and studied on the modified nickel on an alumina support catalysts. The results are that dienes are reduced by at least 80% to 90% and monoolefins reduced little. The modified catalyst shows better selectivity and stability. The optimal content of nickel and magnesium are 10%, 1.5% by weight of the support, respectively. The reaction operational conditions are also observed and studied. The optimal reaction temperature is 75°C, the liquid hours space velocity (LHSV) is 10 hr−1, the volume ratio of hydrogenation and oil (V H /V O ) is 10, and the reaction pressure is 1.5 MPa. The temperature of calcination is observed as well, and the optimal one is 1, 000°C

The Aromatization of FCC Gasoline Fraction on Modified HZSM-5

In this paper, the FCC gasoline (75∼120○C fraction) is investigated and studied on the HZSM-5 type zerolite catalysts modified with zinc nitrate and ammonium dihydrogen phosphate which are prepared by impregnation method. The results show that Znx–HZSM-5 type zerolite catalysts have a high initial reactivity of aromatization but a rapid deactivation. Compared to Znx–HZSM-5 type zerolite catalysts, the Znx–Py–HZSM-5 type zerolite catalysts not only have more stable reactivity of aromatization but a property of isomerization. The Zn (2%)–P(4%)–HZSM-5 has the best performance among them. Also, the reaction operational conditions are observed and studied on the Zn (2%)–P (4%)–HZSM-5 type zerolite catalyst. The results are that the optimal reaction temperature is 430○C, the liquid hours space velocity (LHSV) is 1 hr−1 and the reaction pressure is 0.1Mpa.

Reaction coupling of diethylbenzene dehydrogenation with water–gas shift over alumina-supported iron oxide catalysts

Starting from the thermodynamic analysis of the coupling of diethylbenzene (DEB) dehydrogenation to divinylbenzene (DVB) with reverse water–gas shift, the dehydrogenation of DEB in the presence of carbon dioxide over alumina-supported iron oxide catalysts was carried out at 450–650 °C under atmospheric pressure with CO 2/DEB mole ratio of 10–70 and DEB liquid space velocity (LHSV) of 0.2–1.2 h −1. The effects of reaction temperature, LHSV, CO 2/DEB ratio, as well as iron loading and addition of promoters upon DEB conversion and DVB selectivity were investigated. It was revealed that the yield of DVB and ethylstyrene (EST) could be greatly improved by the reaction coupling due to the simultaneous elimination of the hydrogen produced in the dehydrogenation by reverse water–gas shift. A typical result with EST + DVB selectivity of 90.3%, DVB yield of 43.9% and EST yield of 38.0% was obtained at 550 °C with DEB LHSV of 0.4 h −1 and CO 2/DEB mole ratio of 40.

A Study on Modified HZSM-5 Aromatization for FCC Light Gasoline

In this article, the HZSM-5 type zeolite catalysts modified with zinc nitrate and calcium nitrate are prepared by impregnation method. The FCC gasoline (<75°C fraction) is observed and studied on the modified HZSM-5 type zeolite catalysts. The results are that the Z x -HZSM-5 type zeolite catalysts have a high initial aromatic yield but a rapid deactivation. The C y -HZSM-5 type zeolite catalysts have a lower aromatic yield and a familiar deactivation comparing to Z x -HZSM-5. The HZSM-5 type zeolite catalysts modified with bimetal zinc nitrate and calcium nitrate have a rather low initial aromatic yield but a long catalyst life; among them, the C3.5Z2.0HZSM-5 has the best performance. And also, the C3.5Z2.0HZSM-5 type zeolite catalyst has demonstrated good regenerated performance. After regenerated three times, the catalyst still has a good stability. The reaction operational conditions are also observed and studied. The results are that the optimal reaction temperature is 450–490°C, the liquid hours space velocity (LHSV) is 1 h−1 and the reaction pressure is 0.1 MPa.

New cracked gasoline hydrogenation catalyst launched

The laboratory findings were presented for a single-stage hydrocracking process of vacuum residue (VR) of Ural crude. The Ni–Mo/Al2O3 catalyst in suspension was used in tests. The amounts and quality of the obtained products were related to process parameters. Hydrocracking of VR was carried out in a continuous flow reactor, at the temperature of 410–450 °C and pressure of 12–20 MPa, at the liquid space velocity (LHSV) of 0.25–0.75 h− 1, and at the gas space velocity of 2500 h− 1.The studied catalyst Ni–Mo/Al2O3 was found moderately active in the VR cracking process, while it turned out an efficient catalyst for the hydrofining processes. The catalyst concentration and hydrogen pressure had no effect on hydrocracking of VR, and hydrofining of cracking products was affected slightly only over the studied scope of parameters. The reaction temperature and LHSV exerted dramatic effects on hydrocracking of VR and on the asphaltenes and CCR contents, while their effect on hydrofining of cracking products was much lower. The temperature of 430 °C resulted in VR conversion to distillates (b.p. < 538 °C) of 61.6–88.7 wt.% and in sulphur conversion of 70–85 wt.%.

Heteropoly acid precursor to a catalyst for dibenzothiophene hydrodesulfurization

A silica-supported monometallic tungstophosphoric heteropoly acid (HPA), H 3PW 12O 40, is a novel and efficient catalyst for the hydrodesulfurization of dibenzothiophene (DBT). Over a 30 wt.% HPA/SiO 2 catalyst in a trickle bed flow reactor at industrially relevant gas and liquid space velocities (GHSV 600 h −1 and LHSV 6 h −1) and an H 2 pressure of 30 bar, the hydrodesulfurization proceeds with a DBT conversion of 58% at 290°C and 80% at 350°C. These values are comparable to the performance of the industrial Co–Mo/Al 2O 3 catalyst. No loss of catalytic activity was observed for a period of 56 h. 31P MAS NMR and thermogravimetric analysis (TGA) data show that the HPA decomposes upon interaction with H 2S/H 2 to yield the active hydrodesulfurization catalyst.

Catalytic Oxidation of Substituted Phenols in a Trickle Bed Reactor

The catalytic wet oxidation was studied of phenol, 2-aminophenol, salicylic acid and 5-sulfosalicylic acid performed in a laboratory trickle bed reactor. A three-phase high-pressure catalytic reactor with an inside diameter of 18 mm and length of catalytic bed of 200 mm was operated at temperatures 90-180 °C, pressures 2-7 MPa and liquid space velocity 1-10 h-1. Simultaneously, the catalytic activity and the stability of extruded active carbon black Chezacarb and active carbon Chemviron were tested. At a comparable activity, the active carbon Chemviron exhibited a greater mechanical strength and stability. The influence of phenol substituents on the oxidation conversion corresponded to their inductive effect: The electropositive amino group supported the oxidation, on the contrary, the presence of carboxy and sulfo groups on aromatic ring led to only low conversion. The complications on evaluating the experimental data are caused by the non-isothermal temperature profile along the catalyst bed, the non-ideal oxygen dissolution in aqueous solutions and especially the hydrodynamic effect of flow rate on the degree of catalyst wetting and thus on the entire effectiveness of the oxidation process.

HYDROPROCESSING OF COAL-DERIVED MIDDLE DISTILLATE

ABSTRACT Coal–derived middle distillate, boiling range 437 to 623°K, was hydrotreated in a fixed bed reactor with a commercial NiO–Mo03/ Al2O3 catalyst. The feedstock contained predominantly highly–substituted aromatics. The product heteroatom content and aromaticity decreased with increased process temperature or pressure. Aromaticity was proportional to liquid space velocity. Heteroatonms could be effectively reduced at hydroprocessing conditions of 653°K, 10 MPa, and 2 WHSV. Experimentally–derived cetane number was found to be proportional to product aromaticity. Severe hydroprocessing conditions were required to produce diesel fuel of acceptable cetane number.

Changes within tin-containing catalysts under hydrorefining conditions

Tin compounds have generally been found particularly effective in liquid phase coal hydrogenation processes [1--4]. Recent studies have included the use of tin catalysts in hydrorefining of coal-derived feeds such as asphaltenes [2] and solvent refined coal [4]. Although much at tent ion has been given to the activity of supported and unsupported tin catalysts, little effort has been made to examine the fate of the tin during the hydrorefining process. The development of catalysts for upgrading of Canadian oil-sand bitumen and for conversion of coal into liquid products has been of considerable interest at the Energy Research Laboratories. Guided by the outcome of previously published work, a series of tin-containing catalysts was tested for bitumen upgrading. Emphasis was placed on studying the changes occurring within the catalysts during this process. Results obtained in preliminary tests stimulated further development such as the use of different methods of catalyst preparation. Athabasca bi tumen was obtained from Great Canadian Oil Sands Ltd., Fort McMurray, Alberta, Canada, and some of its properties are given in Table 1. Tests were carried out in a bench-scale fixed-bed reactor having a volume of 155 cm 3 , a length to diameter ratio of 12 and a continuous upflow arrangement [5]. Experiments were performed at a pressure of 13.9 MPa, a temperature of 440 ° C, a liquid volumetric space velocity of 0.278 ks-' (1.0 h -~ ) based on the reactor volume, and a hydrogen {electrolytic) flow rate of 37.5 cm 3 s -I at STP. The product leaving the top of the reactor

Continuous Hydrogenation of Steam Cracked Gasoline

Studies on continuous hydrogenation of steam cracked gasoline were made, using nickel subsulfide catalyst.The catalyst used was prepared by sulfiding nickel with hydrogen containing hydrogen sulfide in small concentration e.g. 1% by volume, at a low temperature e.g. 200°C, and treating this sulfided nickel with hydrogen or a mixture of hydrogen and hydrocarbon oil at a temperature from 200° to 300°C. Principal constituent of this catalyst was found to be nickel subsulfide, Ni3S2, by X-ray diffraction.The catalyst is active for the hydrogenation of diolefins in steam cracked gasoline but is inactive for the hydrogenation of aromatic nucleus. Such a selectivity has not been found with metallic nickel catalyst.Hydrogenation conditions used were such as follows: temperature 100° to 170°C; pressure 10 to 50kg/cm2, gauge; liquid space velocity 1.0 to 6.2.Since no high polymerization and cracking reactions were observed and catalytic activity and selectivity were constant during the 3.5 months of the catalyst life test, it is expected that the life could be extended further.

Studies on the Activity and Selectivity of the Copper-Chromium-Manganese Oxide Catalysts. VII.

We have examined the activity of the pilled copper-chromium-manganese oxide catalyst which was made by the ordinary pilling machine from the copper-chromium-manganese oxide powder (improved Adkin's type catalyst) mixed with a small amount of water glass, for the hydrogenation of nitrobenzene to aniline in the vapor phase.As the results, we have found that nitrobenzene has been easily hydrogenated to aniline in almost quantitative yields.The optimum hydrogenation conditions are as follows; reaction temperature : 200300°C, liquid space velocity of nitrobenzene to the volume of catalyst (L.H.S.V.) : 0.6, the mol ratio of nitrobenzene to hydrogen is 1 : 2030.But we have observed that at the higher reaction temperature (about 300°C) very small amount of unidentified by-products have been produced during the hydrogenation of nitrobenzene.