Mathematical modelling of thermal microexplosion in a catalyst granule with point sources of heat release

A mathematical model of heat and mass transfer in a spherical catalyst granule is proposed. Exothermic synthesis reactions are carried out on point active centres located inside a porous ceramic granule. From the surface of the granule the heat of catalytic reactions is removed into liquid synthesis products. The rate of a chemical reaction is modelled by a modified Arrhenius law. In contrast to the homogeneous model of a catalytic granule methods for calculating heat transfer processes in a system of point, active centres do not develop. An iterative procedure is suggested to calculate the unknown temperature and concentration of the reagent at the active centre. It is shown that the temperature of the active centres is significantly higher than in the volume of the granule. The results of modelling a thermal explosion with increasing granule size and reactor temperature are presented.

Ammonia converter Simulation and Optimization Based on an Innovative Correlation for (KP) Prediction

In this paper, the simulation and optimization of an industrial ammonia synthesis reactor is illustrated. The converter under study is of a vertical design, equipped with three radial-flow catalyst beds with inter-stage cooling and two quenching points. For building the model, a modified kinetic equation of ammonia synthesis reaction, based on Temkin- Pyzhev equation and an innovative correlation for (KP) prediction, was developed in suitable form for the implementation in Aspen HYSYS plug flow reactor using the spreadsheet embedded in the software with the introduction of some invented simulation techniques. A new parameter, which is a function of (T, P and α), was introduced into the reaction rate equation to account for the variation of KP with pressure. The simulation model is able to describe the converter behavior with acceptable accuracy. A case study was done, using Aspen HYSYS Optimizer, illustrated the optimum reactor temperature profile, after 12 years of operation, to achieve maximum production. The result predicts an increase of 8 tons ammonia per day accompanied with an increase of steam production of 12 tons per day.

Robust Multi-Objective Optimization for Response Surface Models Applied to Direct Low-Value Natural Gas Conversion Processes

The high proportion of CO2/CH4 in low aggregated value natural gas compositions can be used strategically and intelligently to produce more hydrocarbons through oxidative methane coupling (OCM). The main goal of this study was to optimize direct low-value natural gas conversion via CO2-OCM on metal oxide catalysts using robust multi-objective optimization based on an entropic measure to choose the most preferred Pareto optimal point as the problem’s final solution. The responses of CH4 conversion, C2 selectivity, and C2 yield are modeled using the response surface methodology. In this methodology, decision variables, e.g., the CO2/CH4 ratio, reactor temperature, wt.% CaO and wt.% MnO in ceria catalyst, are all employed. The Pareto optimal solution was obtained via the following combination of process parameters: CO2/CH4 ratio = 2.50, reactor temperature = 1179.5 K, wt.% CaO in ceria catalyst = 17.2%, wt.% MnO in ceria catalyst = 6.0%. By using the optimal weighting strategy w1 = 0.2602, w2 = 0.3203, w3 = 0.4295, the simultaneous optimal values for the objective functions were: CH4 conversion = 8.806%, C2 selectivity = 51.468%, C2 yield = 3.275%. Finally, an entropic measure used as a decision-making criterion was found to be useful in mapping the regions of minimal variation among the Pareto optimal responses and the results obtained, and this demonstrates that the optimization weights exert influence on the forecast variation of the obtained response.

Synthesis of Bio-gas Using Squander Cooking Oil

The point of this examination is to evaluate the performance of both catalytic and thermal cracking processes in the thermochemical conversion of squander cooking oil into biofuel and investigate the impact of ZSM-5 impetus and breaking reactor temperature to items yield, biofuel caloric substance and synthetic arrangement. Several parameters might affect process performance which resulted in different product’s yield and specification. Cracking temperature variation gave appreciable effect on yield and product’s caloric values.

THE USE OF LIQUID SMOKE AS LATEX COAGULANT FOR RUBBER FARMER GROUP IN BUKIT LITI VILLAGE, CENTRAL KALIMANTAN

Bukit Liti Village is one of villages located in the Kahayan Tengah Sub-district, Pulang Pisau Regency, Central Kalimantan Province. Most people there tap rubber tree simply managed to produce bokar (rubber materials). In making bokar, rubber farmers use coagulant materials that can damage the rubber quality and soak bokar in water pool/creeks which lower the rubber quality and produce bad smell. To solve the problem, a training is conducted to make a simple pyrolysis reactor to produce liquid smoke which will be used as latex coagulant preventing and reducing bad smell and improving the bokar quality. Pyrolysis reactor is made from a used oil tank, and other materials with a thermometer to measure reactor temperature. The reactor is designed to allow a minimum oxygen combustion. The production of rubber wood liquid smoke for latex coagulation process in this research with 50 kg of old rubber wood materials has obtained 125 ml liquid smoke for 4-hour production time. The use of liquid smoke as latex coagulant gives real impacts for farmers such as: environmental friendly, to prevent bacterial growth and oxidation in the latex and latex lump, to prevent and reduce bad smells of bokar from the plantation, during storage and rubber processing in the rubber processing factory. The technology advantages of the liquid smoke are: faster coagulation, high elasticity, able to increase dry rubber content, relatively same price with other coagulant, to increase quality and selling price, produce clean latex and free of environment pollutant.