Time filter

Source Type

Zhang S.-Y.,Xian Jiaotong University | Zhang X.-H.,East China Engineering Science and Technology Co.
2011 2nd International Conference on Mechanic Automation and Control Engineering, MACE 2011 - Proceedings

The current paper presents the results of numerical study on the shrinkage property of synthetic fiber reinforced cement mortar, including the discussion about the influence of fiber geometry on the shrinkage performance of mortar matrix. Finite element method (FEM) was used to build the numerical models respectively for the free composite and constrained composite. Cooling method was used to simulate the shrinkage of mortar matrix. Based on the thermal-mechanical coupling analysis, shrinkage and average normal stress of the matrix were obtained. Examples show that increasing fiber volume fraction can take effects both on the decrease of shrinkage and average normal stress of mortar matrix. Although X-type fibers with elastic modulus higher than the matrix can provide better antishrinkage property for free mortar, they will increase the average stress in the constrained mortar and thus increase the possibility of original micro-cracks in mortar matrix. X-type fibers with elastic modulus lower than mortar, rather than cylindrical fibers, are suggested for a better achievement in antishrinkage and cracking control. © 2011 IEEE. Source

Ye Y.,East China Engineering Science and Technology Co. | Qian J.,Tianjin University | Xu Y.,Tianjin University
Journal of Polymer Research

This paper presented a model study on maleic anhydride (MAH) grafted polypropylene (PP) performed in melt state through ultrasonic initiation without any chemical initiator and solvent. The structures of PP-g-MAH were characterized by FTIR and 13C NMR and the mechanism were discussed. The graft degree (G) was determined by titration using a solution of organic base tetra-butyl ammonium hydroxide (TBAOH) in ethanol, and the effects of ultrasonic intensity, MAH concentration and styrene (St) on G and graft efficiency (G E ) of MAH were investigated. Results showed that MAH was successfully grafted onto the PP chain and the optimum conditions for grafting were at an ultrasonic intensity of 300 W with a MAH concentration of 25 wt.%, and the maximum G of MAH of 3.34 wt.% was obtained when the molar ratio of St to MAH was 1:1. DSC and XRD were also employed to determine the thermodynamic performance and crystalline structures of the products. © 2011 Springer Science+Business Media B.V. Source

Li W.,Tianjin University | Shi L.,Tianjin University | Yu B.,East China Engineering Science and Technology Co. | Xia M.,Tianjin University | And 3 more authors.
Industrial and Engineering Chemistry Research

In this work, the pressure-swing distillation process is extended to separate the pressure-insensitive binary azeotropes by using suitable entrainers. Design and control of new pressure-swing distillation for separating pressure-insensitive maximum boiling phenol/cyclohexanone azeotrope using acetophenone as a heavy entrainer are investigated using Aspen Plus and Aspen Dynamics. Rigorous steady-state simulations are run for both fully and partially heat-integrated processes and a comparison of these two configurations is made. It is revealed that the partially heat-integrated process is more competitive than the fully heat-integrated one from the economical viewpoint. Two temperature control structures and one composition/temperature cascade control scheme are proposed to handle the feed flow rate and feed composition disturbances. It is indicated that the column operating at higher pressure cannot be perfectly controlled by the two temperature control schemes because of the existence of an intermediate nonkey component. A composition/temperature cascade control structure is proposed to cope with this control problem and a robust control is achieved. © 2013 American Chemical Society. Source

He X.-T.,Tianjin University | Gan A.-H.,Tianjin University | Gan A.-H.,National Engineering Research Center for Distillation Technology | Zhou Z.-S.,East China Engineering Science and Technology Co.
Xiandai Huagong/Modern Chemical Industry

This paper adopts PRO/II developed by SIMSCI company to simulate aromatic extraction process in the practical production, to design, simulate and optimize pre-fractionator, extraction distillation tower, solvent recovery tower, benzene tower, toluene tower and xylene tower, espectively, then to optimize total technological process and give the simulation results. The optimum process operation parameters are finally obtained, which comply with the national quality requirements. Source

Zhuang Q.,CANMET Energy | Clements B.,CANMET Energy | Li Y.,East China Engineering Science and Technology Co.
International Journal of Greenhouse Gas Control

Ammonia-based CO 2 capture technology has attracted wide research interest. Substantial work has been reported that includes theoretical evaluation, laboratory tests, pilot plant tests and economic analysis. Alstom and PowerSpan have conducted a few MW level demonstration tests. However, three inherent hurdles with this potential CO 2 capture technology have not been fully solved yet: ammonium bicarbonate solid formation in the absorption tower which may plug the tower packing, high ammonia vapor pressure that results in ammonia slip into the cleaned flue gas, and low CO 2 absorption rate resulting in large absorption equipment. Industrial ammonium bicarbonate fertilizer production processes are proven technology and have been optimized both technologically and economically for decades. This technology is also based on the chemistry and physics of the NH 3-CO 2-H 2O system. In the ammonia synthesis plant, CO 2 in shifted gas from the syngas obtained by gasification of coal is absorbed into partly carbonated aqueous ammonia in a liquid bubbling column to produce ammonium bicarbonate solid as fertilizer. Using this process, ammonium bicarbonate has been sustainably produced with low ammonia slip into the shifted gas after the CO 2 was captured. In this report, the ammonium bicarbonate fertilizer production process is described and analyzed. The advantageous aspects of the fertilizer production technology are compared with the current widely studied ammonia-based CO 2 capture technology for power plant applications. Insights into the modifications required for the flue gas CO 2 capture application are discussed. New designs of ammonia-based CO 2 capture processes are presented. © 2012. Source

Discover hidden collaborations