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Effect of Ultrasonic During Preparation on Cu-Based Catalyst Performance for Hydrogenation of CO₂ to Methanol
M Nasikin,
A Wahid

111

Indonesia has very big natural gas resources. These resources contain hydrocarbons and any impurities such as CO₂. CO₂ creates a difficulty in further gas treatment and also becomes environmental problem. Therefore it is needed to develop a concept to recover this kind of gas and to convert to be more useful chemicals. Catalytic hydrogenation to methanol is one of technology that can be considered.

Conversion of CO₂ to methanol can be catalyzed by Cu based catalyst that has been reported to be the best catalyst. Therefore, this catalyst is selected as a catalyst for pilot plan that is operated at a high pressure and a high temperature. However, further development is needed for rearranging the synthesis to be operated at both lower pressure and temperature. For this system, it is needed to increase catalyst activity that one of an alternative is to apply a catalyst preparation method to use ultrasonic effect.

In this research work, CuO/ZnO/Al₂O₃ catalyst with Cr as a promoter was prepared by co-precipitation method. Effect of ultrasonic on the catalyst performance, which was irradiated to the catalyst during preparation, was investigated. Co-precipitation was conducted by using carbonate salt for respective metal cations added to the catalyst. Ultrasonic wave was irradiated to catalyst preparation chamber with 40kHZ and at 30, 60 and 90 minutes. Characteristic of the catalyst was analyzed by BET method for surface area, SEM and H₂ chemical adsorption was conducted for determining of active site dispersion. A high-pressure continuous flow reactor was used for catalyst’s activity and stability test. The test was conducted at operation condition of 30 bars and 200~300^oC.

The effect of ultrasonic for the CuO/ZnO/Al₂O₃ catalyst shows that ultrasonic irradiation enhances catalyst surface from 23 to 50m2/g. SEM analysis shows the change of the catalyst morphology to be more uniform and the catalyst particle becomes smaller. Activity test shows that the catalyst with 60 min irradiation time has the highest activity in hydrogenation of CO₂ to methanol at 30 bars and 275^oC.

An Interesting Final-Year Undergraduate Project: Investigation of Gypsum Scale Formation on Piping Surfaces
S. Muryanto,
H. M. Ang

116

The formation of scales in pipes and on the surfaces of vessels is one of the major problems encountered by the mineral processing industry in Australia and elsewhere. A cursory study revealed that one of the main components of the scales was gypsum or calcium sulfate dihydrate. This paper discusses a typical undergraduate laboratory project to investigate the formation of calcium sulfate dihydrate scale on the surfaces of different types of pipes under isothermal conditions. This laboratory exercise is essentially a crystallization process and is suggested as one of the topics for final-year chemical engineering undergraduate project since it is a very important unit operation in the chemical, mineral, or pharmaceutical industries.

Utilization of Mathematical Software Packages In Chemical Engineering ResearchSynthesis of Robust Water Reuse Networks Using Fuzzy Nonlinear Programming: Mass Exchange-Based Processes
Ang Wang Lee
Nayef Mohamed Ghasem
Mohamed Azlan Hussain

125

Using Fortran taken as the starting point, we are now on the sixth decade of high-level programming applications. Among the programming languages available, computer algebra systems (CAS) appear to be a good choice in chemical engineering as they can be applied easily. Until the emergence of CAS, the assistance from a specialized group for large-scale programming is justified. Nowadays, it is more effective for the modern chemical engineer to rely on his/her own programming ability for problem solving. In the present paper, the abilities of Polymath, Maple, Matlab, Mathcad, and Mathematica in handling differential equations are illustrated for differential-algebraic equations, large system of nonlinear differential equations, and partial differential equations. The programming of solutions with these CAS are presented, contrasted, and discussed in relation to chemical engineering problems.

Photodegradation Kinetics of Phenol and Methylene Blue Dye In Water Stream Over Immobilized Film TiO₂ Catalyst
Chin Mei Ling
Abdul Rahman
Mohamed Subhash Bhatia

131

A photocatalytic reactor has been designed to study the kinetics of photocatalytic degradation of phenol and methylene blue dye present in water stream on immobilized TiO₂ catalyst. The principal part of the reactor consisted of a cylindrical pyrex glass tube whose outer surface was coated with the synthetic TiO₂ film catalyst prepared from sol-gel technique. An ultraviolet light lamp of 365 nm wavelength was set longitudinally in the center of the tube. The synthetic TiO₂ film formulation with the molar ratio of 1 titanium isopropoxide : 8 isopropanol : 1.1 H₂ O : 3 acetyl acetone : 0.05 acetic acid was used to develop the immobilized TiO₂ film catalyst deposited over the glass support. The performance of the immobilized photocatalytic reactor was evaluated by studying the decomposition kinetics of phenol and methylene blue dye present in the aqueous stream. The kinetics of photocatalytic degradation of phenol and methylene blue obeyed first order heterogeneous equation. The kinetic parameters were evaluated from the kinetic data using the Langmuir-Hinshelwood-Hougen-Watson (LHHW) model.

Ranking of Waste Management Options Under Conditions Of Possibilistic Uncertainty Using Fuzzy SAW
Raymond Girard R. Tan

140

Integrated waste management involves the use of appropriate techniques ranging from pollution prevention/cleaner production (P2/CP) to conventional end-of-pipe controls. Design or retrofit of process plants usually entails selection of an optimal waste management measure from a number of alternatives. The selection process involves consideration of multiple criteria and data uncertainty, the latter being arguably possibilistic (fuzzy) rather than probabilistic (random) in nature. A fuzzy simple additive weighting (SAW) algorithm is proposed for such problems and demonstrated on a case study. The principal feature of the techniques shown is the retention of fuzzy confidence levels during the assessment of different technological options.

NO Reduction by Carbon Monoxide Over Cobalt on Zeolite Beta
Jatuporn Wittayakun
Nurak Grisdanurak
Banjamart Nuntaitawegon
Gerald Kinger
Hannelore Vinek

147

This study focused on the selective catalytic reduction of nitric oxide (NO) by carbon monoxide (CO) over cobalt supported on zeolite beta (Co/BEA) with and without the presence of oxygen or water. The Co/BEA catalyst with 2.6% metal loading was prepared by solid state ion exchange from freshly synthesized HBEA and CoCl₂•6H₂O. The adsorption behavior of NO on Co/BEA investigated by temperature programmed desorption (TPD) revealed two peaks for NO at 100 and 260 °C indicating that there were at least two adsorption modes. The desorption of CO completed near 200°C along with a small amount of CO2.

The activity of Co/BEA catalyst for NO reduction by CO was lower than 20% at 100–300°C but higher than 50% at 400–500°C with the maximum conversion of 60% at 500°C. Products were selectively N2 and CO₂. However, the activity in the presence of oxygen was low due to the more favorable reaction between CO and O₂ to form CO₂. The catalytic activity in the presence of water was also low but higher than that in the presence of oxygen.

Effect of Basis Sets on the Selection of the Appropriate Level of Theory Toward the Development of Quantum-Based Force Field Equation for Ionic Liquids
A. N. Soriano
B. T. Doma, Jr.

156

The chemical industry is under considerable pressure to replace many of the volatile organic compounds. Volatile organic compounds are a major contributor to air pollution, but out of necessity, they are still frequently used in many chemical and industrial processes. A new class of solvents, referred to as ionic liquids, may offer at least a partial solution to the pollution problem caused by volatile organic compounds. Ionic liquids are generally considered “green” solvents because of their environment-friendly properties. However, the main problem that hinders the chemical industry from using ionic liquids is that, compared to conventional organic solvents, relatively little is known about their thermodynamic and transport properties. Since there are large possible combinations of ionic liquids, it would be very expensive if the study were conducted in the laboratory. The more appropriate approach in studying the properties of ionic liquids is to engage in a computational method, which uses a computer software that evaluates ionic liquids’ thermophysical quantities via quantum mechanical and molecular mechanical simulations. In this study, a computer simulation, with the aid of SPARTAN ’02 software, is used to study the effect of basis sets on the selection of the appropriate level of theory, which would be employed later in developing a quantum-based force field equation for predicting the properties of ionic liquids. Using the Hartree-Fock self-consistent filled (HF-SCF) molecular orbital model with different basis sets, a single point energy calculations were carried out for the chosen ionic liquid. With the exception of the minimal basis set, the SCF total energies for the other basis sets agree with each other in terms of magnitude. The SCF total energy is not affected as the basis set varies from minimal to split valence and as it polarizes. The most appropriate basis set was found to be 6-31G*.

Integrating Performance Indicators Into the Audit of Satety Management Systems
C. R. Che Hassan
M. J. Pitt
A. J. Wilday

161

Performance indicators at each level of the sociotechnical pyramid for a range of areas of work in which accidents have been shown to occur most frequently. The measurement of performance indicators is part of a feedback loop which causes safety improvements. Integration of performance indicators into the audit system has been tested at three operating chemical industries in Terengganu and Selangor in Malaysia. A summary of the weaknesses of the similar elements identified in the three audited plants is presented. Analysis on the approach used enables the identification of deficiencies in safety management aspects.

Kinetic Consideration of Clinker Formation in Portland Cement Production Using Demolition Rubbles (Concrete, Mortar, and Plaster), Part I. Burning Ability of Raw Mixes
Sumardi P.
Ida Bagus Agra
I. Made Bendiyasa
Wahyudi Budi Sediawan

169

In general, the main raw materials in Portland cement production are limestone, clay, and corrective materials such as iron sand and silica sand. These raw material come from natural deposits, which are very hard to find in some countries. In this research, Portland cement was made by utilizing the demolition rubble of office and housing buildings. The rubble consists of concrete wastes (mixtures of hydrated Portland cement minerals and some aggregates) and some building bricks as well as mortar/plaster of Portland cement. To meet the cement modulus, which is generally used in Portland cement industries, corrective materials such as limestone (source of CaO) and disposed building bricks are used. The term burning ability is used for Portland cement to measure the CaO free content in the cement clinker produced from specified raw material mixes at a specific operating condition of clinkering. The cement modulus used is Lime Saturation Factor (LSF) and Silica Modulus (SM). The minimum CaO free content was found by using LSF: 0.86, SM: 2.14, and clinkering temperature 1400°C for 30 minutes. The cement modulus was made from concrete waste, limestone, and disposed red brick with a weight ratio of 1: 3.489: 0.677.

Propane Dehydrogenation in a Modified Porous Membrane Reactor For Producing Propylene with Chemical and Polymer Grades
Azis Trianto
Yazid Bindar
Noezran

176

Propane dehydrogenation is a promising route for producing propylene to replace traditional cracking methods. A membrane reactor offers a possibility to produce not only chemical grade but also polymer grade of propylene. The purpose of the present study is to evaluate the performance of a Modified Porous Membrane Reactor (MPMR) in producing these two propylene grades simultaneously. The study involves evaluations based on thermodynamics and process flow sheeting. The performance of this reactor is compared to that of conventional reactor. At first, the thermodynamics is conducted using minimum Gibb’s Energy approach. Then the process flow sheeting evaluation is built using the HYSYS simulator. The effect of inert gas (steam) concentration in both sweep and feed sides is investigated. The thermodynamics study results optimum temperature and inert gas concentration to obtain these two grades of propylene simultaneously. The propylene with polymer grade above 99% is produced from the sweep side outlet. The propylene with chemical grade is produced from the feed side outlet. The simultaneous production of these two grades of propylene has benefit in vanishing propane–propylene splitter.

About the Authors

183

Guide for Authors in Manuscript Preparation

191