探讨粮油加工环节中的质量安全问题及对策

我国粮油产品质量安全存在较多的问题,尤其粮油在加工环节容易被各种污染问题,如粮油加工机械产生的油烟及灰尘、加工过程添加非法的食品添加剂等。本文将探讨粮油加工环节的质量安全问题,并提出相应的解决对策。     

数字化时期建筑标准化分析

论述了建筑标准化与线性思维的关系,介绍了数字化时期建筑标准化的特点,并探讨了数字化时期建筑标准化的参数化设计方法,指出数字化时期的建筑标准化是非线性思维下的建筑标准化,体现的是整体性、动态性和复杂性特点。     

2000t/a海藻酸钙短纤维生产线的开发

介绍了海藻酸钙纤维的性能特点和当前状况。结合450 t/a海藻酸钙短纤维生产线流程,对2 000 t/a海藻酸钙短纤维生产线的流程设计进行了探讨。根据2 000 t/a海藻酸钙短纤维生产线的流程和主要工艺参数,分析了生产线上主要设备的结构形式、结构特征及研发重点。     

倒三角形拼装桁架桥的极限承载力分析

对一种新型的倒三角形拼装桁架桥的整体稳定性进行研究。借助通用有限元分析软件ANSYS建立长度为51m桥梁的有限元模型,通过与桥梁静载试验对比验证有限元模型的可靠性。在此基础上考虑几何和材料双重非线性,进行非线性屈曲分析。采用弧长法追踪桥梁在荷载作用下的荷载-位移曲线,得到桥梁在多种跨度下的极限承载力和稳定安全系数。研究结果对同类桥梁的设计具有一定的参考价值。     

Modeling and simulation of hydrogen production from dimethyl ether steam reforming using exhaust gas

In this paper, hydrogen production from steam reforming of DME (dimethyl ether) has been modeled and simulated using a CFD (computational fluid dynamics) method. The reformation chemistry occurs in a porous catalytic bed where exhaust gas is supplied through the EGR (exhaust gas recycling) valve of the engine to drive the endothermic reaction system. The tightly coupled system of mass, energy, and momentum equations are used to describe the complex physical and chemical process of DME steam reforming. The global reaction kinetics for the reforming is adopted in the CFD model. The mathematical models are introduced into the commercial software Comsol, and then numerical simulations are also performed based on this model. The model predictions are quantitatively validated by experiment data. The simulation results indicate the temperature distribution, mass distribution, DME conversion, and hydrogen production from steam reforming of DME. In addition, the fuel to steam ratio and velocity of exhaust gas are manipulated as operating parameters. These simulation results will provide helpful data to design and operate a bench scale catalytic fluidized bed reactor. Copyright © 2015 John Wiley & Sons, Ltd.     

生产国V汽油的RSDS-III技术开发

The 3rd generation catalytic cracking naphtha selective hydrodesulfurization(RSDS-III) technology developed by RIPP included the catalysts selective adjusting(RSAT) technology, the development of new catalysts and optimized process conditions. The pilot plant test results showed that the RSDS-III technology could be adapted to different feedstocks. The sulfur content dropped from 600 μg/g and 631 μg/g to 7 μg/g and 9 μg/g, respectively, by RSDS-III technology when feed A and feed B were processed to meet China national V gasoline standard, with the RON loss of products equating to 0.9 units and 1.0 unit, respectively. While the feed C with a medium sulfur content was processed according to the full-range naphtha hydrotreating technology, the sulfur content dropped from 357 μg/g in the feed to 10 μg/g in gasoline, with the RON loss of product decreased by only 0.6 units. Thanks to the high HDS activity and good selectivity of RSDS-III technology, the ultra-low-sulfur gasoline meeting China V standard could be produced by the RSDS-III technology with little RON loss.