Advanced Materials Research Vols. 550-553

Abstract: A large-scale cold model experimental setup of combined riser with variable constraint exit (CRVCE) was established. The axial and radial distributions of solids holdup and particle velocity, under different operating conditions, were investigated experimentally, and the results were compared with conventional riser (CR). Experimental results showed that, the exit restrictive effect of combined riser with variable constraint exit was weak when particle circulation flux and static bed height in upper fluidized bed were lower, while it turned to be strong when superficial gas velocity and static bed height in upper fluidized bed were higher. Under the same conditions, averaged cross-sectional solids holdup of CRVCE was characterized by C type distribution when article circulation flux was higher, while that of CR with weak constraint exit was characterized by linear distribution. In axial direction, averaged cross-sectional particle velocity of CRVCE changed in order: acceleration-constant-decrease velocity, while that of CR changed in another: acceleration-constant velocity. The maximum of local solids holdup value of CRVCE appeared at the dimensionless radius position r/R=0.7, while that of CR appeared in the wall region. Their local particle velocities were similar in the core region, while local particle velocity of CRVCE was lower than that of CR in the annular region.

Abstract: The producing of artificial diesel oil and artificial glycol from 75% and 60% water and the rest were commercial diesel or glycol respectively and a little same special additive are reported. The main contents in both liquid were measured. The test results show that the density and the calorific value of the artificial diesel oil were close to the added original diesel oil, but its solidifying point decreased a lot. The elements of the artificial diesel oil are mainly carbon and hydrogen. Infrared spectrum diagrams also showed that there was no water in it. As a whole, the artificial diesel oil is not an oil-water emulsion, but a hydrocarbon liquid even after depositing for 13 years. In the artificial glycol the contents of hydrogen and carbide are closed to the theoretical value but it contained 0.45% water. The above mentioned two important facts show that the new chemical engineering utilizing water will be a very promising area in the near future.

Abstract: Keywords: Biodiesel, Base catalyst, Waste Fried Oil, Orthogonal design Abstract: In this article the biodiesel production procedure of base-catalyzed esterification was studied, and the optimal conditions of preparation were brought up. By applying orthogonal design, the optimal conditions of base-catalyzed esterification from waste frying oil with acid value of 4 mg/l KOH were: methanol/oil ratio, 8:1; catalyst dose, 1% oil weight; temperature, 85°C; reaction time, 1.5 h. The maximum oil conversion rate of 90% was achieved. The influence of each factor on the oil production in descending order was: methanol/oil ratio > catalyst dose > temperature > reaction time. The biodiesel refinement was carried out with three types of rinsing solutions: distilled water, satirized NaCl solvent and glacial acetic acid. Rinsing times, soap removing rate and final acid value of the biodiesel were considered as the critical factors in evaluating the effectiveness of the rinsing solution on the biodiesel refinement. The results turned out that the most suitable rinsing method for industrial application was rinsing with saturated NaCl solvent.

Abstract: As one kind of renewable energy, bio-energy attracts more and more scholars’ attention due to its good ignition, combustion characteristics and zero CO2 release during bio-energy combustion process, alkali metals’ emission could cause fouling, slagging, high temperature corrosion and ultra-fine particulate matter emission, which hazard equipment safety and human healthy. In this paper, the release characteristics of alkali metals during the combustion process of rice straw (RS) and sawdust (SD) was studied by the chemical desperation disposal method and in a vertical thermal balance furnace. Also, the concept of alkali metals’ release ratio was introduced. The Results indicated that increasing the combustion temperature leads to a bigger alkali metals’ release ratio. At the same temperature, the alkali metals release ratio of unwashed biomass is the largest, the acid-washed biomass is the smallest, and the water-washed biomass is in between them. Meanwhile, the existing forms of alkali metals cause different effect to the release ratio, i.e. the ionic form alkali metals release most greatly, the organic form smaller and the other forms the smallest.

Abstract: A new approach was proposed to remove sulfuric compounds from fluid catalytic cracking (FCC) gasoline by combining an alkylation desulfurization catalytic distillation (ADCD) column with a hydrodesulfurization catalytic distillation (HDS-CD) column. In the ADCD column, isobutylene (IB) and 3-methylthiophene (3MT) were designated as the model compounds for olefin and sulfide, respectively; NKC-9 cation exchange resin was used as the catalyst. In the HDS-CD column, dibenzothiophene (DBT) was chosen as the model sulfides; Nickel phosphide supported on the TiO2-Al2O3 composite oxide prepared by our laboratory were designated as the HDS catalyst. Simulations for these two CD columns were carried out by RADFRAC module of Aspen Plus. The optimization results revealed that the ADCD column had an alkylation selectivity of 96%, and the sulfur content in the overhead stream was less than 8 μg/g. The simulation results of the HDS-CD process showed that the sulfide in the bottom stream of ADCD column can be removed practically by 100% and the clean oil stream from the bottom of HDS-CD column has hardly any sulfur.

Abstract: The Sulfur-Iodine (SI) thermochemical hydrogen production process is promising method for the massive production of hydrogen using the high temperature thermal energy of VHTR. For continuous operation of SI process, the conditions of Bunsen reaction are considered as the pressurized conditions with ca. 373~393K temperature and the composition of Bunsen products should be kept constant during the reaction. Therefore, we carried out the continuous Bunsen reaction using a counter-current flow reactor at pressurized condition to investigate the phase separation characteristics of pressurized Bunsen reaction. As the results, the composition of Bunsen product was maintained constantly as the evidence for the steady-state operation. The continuous reaction was operated without occurrence of side reactions, and a H₂SO₄ phase and HI_x phase as the product contains a small amount of impurities (HI in a H₂SO₄ phase and H₂SO₄ in a HI_x phase). We concluded that the pressurized Bunsen reaction is favorable to the continuous operation of SI process than the atmospheric reaction.

Abstract: Ethanol was selected as a model compound of bio-oil. Pd/HZSM-5 catalyst with 5%wt Pd was prepared by wet impregnation method. The steam reforming experiment for hydrogen production was carried out on a fixed bed reactor. The carbon conversion, carbon selectivity of product gas and H2 yield was calculated according the experimental resultsl. It has been found that the best performance was obtained at T=700°C, S/C=9.2 and GC1HSV=346h-1. At this condition, the hydrogen yield and potential hydrogen yield can be as high as 58.1% and 84.3%. The results show that the addition of Pd to HZSM-5 can improve the reforming performance and increase the hydrogen yield.

Abstract: The effects of ultrasonic on bleaching of cane fiber were discussed in this paper. Ultrasonic frequency, ultrasonic time, the concentration of the hydrogen peroxide, temperature and pH value were optimized by the single factor experiment. The bleached fiber was analyzed by X-ray diffraction and Scanning electron microscope. The results showed the optimum processing parameters as follows: ultrasonic time 40 min, ultrasonic frequency 33 KHz (first 20 min); 55 KHz (second 20 min), temperature 90°C and the concentration of the hydrogen 30 ml/L, pH value 10.5. In the above conditions, the best bleaching effect was achieved.

Abstract: Hydrogen is a valuable gas as a clean energy source and as feedstock for some industries. Therefore, demand on hydrogen production has increased considerably in recent years. Food waste is an important part of urban living garbage,which is full of organic matter and easy to be degraded. So, biological production of hydrogen gas from food waste fermentation has significant advantages for providing inexpensive and clean energy generation to help meet the needs of carbon emission reduction with simultaneous waste treatment. This article reviews the following aspects: mechanism of fermentative hydrogen production by bacteria, and factors influencing fermentative bio-hydrogen production. In addition,the challenges and prospects of bio- hydrogen production are also reviewed.

Abstract: The wet flue gas desulfurization has been the most widely used in the coal-fired power plants because of high SO₂ removal efficiency, reliability and low utility consumption. A mathematical model of limestone/gypsum wet flue gas desulfurization (WFGD) system was developed based on the two-film theory of mass-transfer. In the one-dimensional two-film theory , the concentration of SO₂ in the bulk of the liquid(cAs) is difficult to accurately determine. The authors derive the accurate calculation of the value of cAs on the basis of the one-dimensional mass transfer model, making the model in line with the actual process. The model predictions were verified by experimental data. Experimental investigations of the effects of different operating variables on the SO₂ removal showed the reasonable process parameters such as the pH value of the liquid phase, droplet size of the spray and the flow rates of liquid and gas. Keep the slurry flow in a 50 ml/min, adjust the flue gas flow changes. Keep the flue gas flow in 5 l/min, adjust the flow slurry changes. The experimental results reveal that the model can describe the processes in this absorber well. Some experimental parameters (temperature, flue gas velocity) are difficult to accurately control, the model can give them fluence on the desulfurization efficiency.