Samuel J.M. Cartaxo

Extraction of lipids from microalgae by ultrasound application: Prospection of the optimal extraction method

Microalgae have the ability to grow rapidly, synthesize and accumulate large amounts (approximately 20-50% of dry weight) of lipids. A successful and economically viable algae based oil industry will depend on the selection of appropriate microalgal strains and the selection of the most suitable lipid extraction method. In this paper, five extraction methods were evaluated regarding the extraction of lipids from Chlorella vulgaris: Bligh and Dyer, Chen, Folch, Hara and Radin, and Soxhlet. Furthermore, the addition of silica powder was studied to evaluate the introduction of more shear stress to the system as to increase the disruption of cell walls. Among the studied methods, the Bligh and Dyer method assisted by ultrasound resulted in the highest extraction of oil from C. vulgaris (52.5% w/w). Addition of powder silica did not improve the extraction of oil.

Prediction of Fischer–Tropsch Synthesis Kinetic Parameters Using Neural Networks

Abstract The kinetic mechanism of the Fischer–Tropsch synthesis (FTS) is complex resembling a polymerization reaction. The kinetic rate constants for initiation, propagation and termination steps and the constants for the equilibrium reactions for methylene formation (in situ monomer) need to be estimated. A mathematical model for the FTS allows for simulating several operating conditions and determining the best operating conditions to produce a specific product distribution, so the kinetic parameters must be statistically valid. This work used neural networks (NNs) to estimate the FTS kinetic parameters, instead of using methods based on least squared error. The results show that NNs with three hidden layers were able to output good estimates of the kinetic parameters with less than 5% of deviation.

Simulation and Optimization of H2 Production by Autothermal Reforming of Glycerol

Abstract This case study focused on optimization of hydrogen production for fuel cell applications. In this case study, glycerol was chosen as a raw material and with autothermal reforming as a process of produce hydrogen. Using a commercial dynamic flow sheeting software, HYSYS 3.1, the process of hydrogen production was successfully simulated. In this research, fuel processor consists of an autothermal reactor, three water gas shift reactors and a preferential oxidation reactor was successfully developed. The purpose of this case study is to identify the effect of various operating parameters such as air-to-fuel (A/F) ratio and steam-to-fuel (S/F) ratio to get the optimum hydrogen production while made carbon monoxide lower than 10 %. From the results, an optimum A/F and S/F ratio are 5.5 and 3.5, respectively to produce hydrogen — 34.7 % (v/v), CO2 — 60% (v/v), and CO — 0.02% (v/v). Under these optimum conditions, 83.6% of fuel processor efficiency was achieved.

Educational software for heat exchanger equipment

Computer‐aided design has become extremely popular and its use in classroom can be very helpful, adding more analysis capabilities to all engineering areas. This article presents HEDes, an educational software developed to introduce heat exchanger equipments to undergraduate students and to provide unit operation courses with realistic exercises involving simulation of chemical processes.

An Object-Oriented Graphics Interface Simulator for Analysis of Fischer-Tropsch Synthesis

This paper describes a computer program that increases the productivity of petrochemical scientists conducting research on Fischer-Tropsch synthesis. FTSlurry integrates Fortran 90 simulation codes with a graphical front end and various visualization tools developed in Delphi. The software serves to evaluate operating process conditions and reaction kinetics on the product distribution of Fischer-Tropsch synthesis carried out on slurry reactors. The software allows for full parameter analysis and study of factor effects. A detailed description of the system architecture and a typical scenario of usage are presented, along with parameter analysis and visualization features.