Showing papers by "Beijing Institute of Petrochemical Technology published in 2004"

On three-dimensional geological modeling and visualization

Abstract: The technology of 3D geological modeling will bring about great changes in the methods of geological data acquiring, storing, processing and displaying. However, no perfect or convenient software systems have been developed up to now since the geologic data which reflect geological entities bear the feature of diversity, uncertainty and complexity. Some super voxel models, mathematical models of fault and geometrical models of fold have been contrived so as to show the space geometric configuration of the complicated geologic structures. The application-oriented system architecture for 3D geological modeling is established; and a novel design concept based on spatial data processing is also proposed with the technology of solid modeling as its core and the application of models as its objective. Theories and methods for 3D geological modeling will hopefully be enriched and developed. In the light of these theories and methods, a feature-based navigation visualization technique is also put forward in the paper. By integrating geo-database, graphics libraries and KBS with 3D dynamic simulation systems, geologists will be able to capture the partial characteristics and whole structure embodied in the geological data in a direct-viewing, figurative and accurate manner.

Study of Canadian FCC Feeds from Various Origins and Treatments. 1. Ranking of Feedstocks Based on Feed Quality and Product Distribution

Abstract: Accurate ranking of fluid catalytic cracking (FCC) feeds will help oil producers price their commodities. The value of an FCC feed depends on its properties, which, in turn, contribute toward producing high-value products with good qualities. Feed ranking based on general analyses is the simplest way to determine the best feeds but can be misleading for some. In this study, the authors propose a feed grading method with consideration of only concentrations of gasoline precursors, total nitrogen, and microcarbon residue (MCR), assuming that gasoline is the most desirable product. By assigning the merit and discount values of the three elements, the relative gasoline yield of a feed can be calculated and its apparent feed rank established. The method was tested on 10 feeds that were catalytically cracked in both a microactivity test (MAT) unit and a riser pilot plant. With some exceptions, the apparent feed ranks indicated an agreeable order with those based on individual high- and low-value MAT product yie...

Experimental Study of Oxygen Mass Transfer Coefficient in Bubble Column with High Temperature and High Pressure

Abstract: The volumetric gas-liquid mass transfer coefficient, k L α, for oxygen was studied by using the dynamic method in slurry bubble column reactors with high temperature and high pressure. The effects of temperature, pressure, superficial gas velocity and solids concentration on the mass transfer coefficient are systemically discussed. Experimental results show that the gas-liquid mass transfer coefficient increases with the increase in pressure, temperature, and superficial gas velocity, and decreases with the increase in solids concentration. Moreover, k L α values in a large bubble column are slightly higher than those in a small one at certain operating conditions. According to the analysis of experimental data, an empirical correlation is obtained to calculate the values of the oxygen volumetric mass transfer coefficient for a water-quartz sand system in two bubble columns with different diameter at high temperature and high pressure.

Bubble Behavior of a Large-Scale Bubble Column with Elevated Pressure

Abstract: Gas holdups and the rising velocity of large and small bubbles are measured using the dynamic gas disengagement approach in a pressured bubble column of 0.3 m in diameter and 6.6 m in height. The effects of superficial gas velocity, liquid surface tension, liquid viscosity, and system pressure on the gas holdups and the rising velocity of small and large bubbles are investigated. The holdup of large bubbles and the rising velocity of small bubbles increase with increasing liquid viscosity and liquid surface tension. Meanwhile, the holdup of small bubbles and the rising velocity of a swarm of large bubbles decrease. Moreover, the holdup of large bubbles and the rising velocity of a swarm of small bubbles decrease with increasing system pressure. A correlation for the holdup of small bubbles is obtained from experimental data.

Study of Canadian FCC Feeds from Various Origins and Treatments. 2. Some Specific Cracking Characteristics and Comparisons of Product Yields and Qualities between a Riser Reactor and a MAT Unit

Abstract: Ten vacuum gas oil feeds were cracked in a fixed-bed microactivity test (MAT) unit and a modified ARCO riser reactor on separate occasions. Several important observations from the MAT study were reported, including the effects of gasoline precursors on the maximum gasoline yields, light cycle oil (LCO) precursors on the optimum LCO yields, and aromatics in feeds on the conversion levels at which the maximum gasoline yields occurred. The yield profiles were similar, in regard to shape and relative position, between H2S-free dry gas and catalytic coke for all but one of the feeds. A method to check the qualities of the MAT and riser data was demonstrated by plotting the coke or total gas selectivity versus the gasoline selectivity. Individual yields of gas, liquid, and coke from MAT at conversions of 55, 65, 70, and 81 wt % were compared with their respective pilot-plant data. MAT results, with the exception of coke yield, were, in most cases, within 15% of the corresponding riser yields. Good linear correl...

Thermochemical and thermal analysis on N-(p-methylphenyl)-N'-(2-pyridyl)urea

Abstract: Low temperature heat capacities of N-(p-methylphenyl)-N'-(2-pyridyl)urea were determined by adiabatic calorimetry method in the temperature range from 80 to 370 K. It was found that there was not any heat anomaly in this temperature region. Based on the experimental data, some thermodynamic function results were obtained. Thermal stability and decomposition characteristics analysis of N-(p-methylphenyl)-N'-(2-pyridyl)urea were carried out by DSC and TG. The results indicated that N-(p-methylphenyl)-N'-(2-pyridyl)urea started to melt at ca. 426 K (153°C) and the melting peak located at 447.01 K (173.86°C). The melting enthalpy was 204.445 kJ mol-1 (899.6 J g-1). The decomposition peak of N-(p-methylphenyl)-N'-(2-pyridyl)urea was found at 499.26 K (226.11°C) from DSC curve. This result was similar with that from TG and DTG experiment, in which the mass loss peak was determined as 500.4 K (227.2°C).

ONIOM study of one‐carbon unit transfer from imidazolidine to dUMP analogue

Abstract: The ONIOM quantum mechanics method is used in this article to study one-carbon unit transfer from an imidazolidine to 6-aminouracil derivates. The computation results show that this reaction can be completed via three paths, owing to the three different proton transfer modes. Each path experiences three processes of nucleophile attacking, proton transferring, and bond rupturing. The focus of discussion falls on the proton transfer process. By analyzing the calculation results, we find that the direct proton transfer is the preferable pathway. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004

Measurement of hot-rolling velocity by using correlation method of velocity measurement

Abstract: Method and principle of on-line velocity measurement of mobile objects by using correlation technique is introduced.By means of ingenious measurement of correlative signals upstream and downstream,passing time of corresponding peaks of correlative signals is computed and the motion velocity of rolled objects is indirectly meansured.A practicable non-contact on-time correlation velocimeter is developed.This velocimeter has already used for measurement of motion velocity of hot-rolled steel in Ma'anshan Steel Works.