Program simulasi kesetimbangan termodinamika non-stoikiometri untuk proses gasifikasi biomassa dikembangkan dengan bahasa pemrograman Python. Program simulasi dilengkapi dengan antar muka program atau lebih dikenal sebagai GUI (Graphical Users Interface), untuk mempermudah interaksi pengguna dalam menggunakan program simulasi. Program dirancang untuk menghitung komposisi gas produser dengan 6 komponen yang terlibat, yaitu CH4, CO, CO2, H2, N2, dan H2O. Rancangan algoritma komputasi perhitungan model kesetimbangan termokimia non-stoikiometri dikonversi ke dalam kode program bahasa Python. GUI terdiri dari fasilitas input data dan output berupa tabel dan grafik hasil perhitungan. Fasilitas input data dirancang sedemikian rupa sehingga pengguna dapat memvariasikan input, yaitu suhu gasifikasi dan rasio equivalen. Hasil perhitungan keluaran program simulasi diverifikasi dengan data hasil perhitungan secara manual untuk meyakinkan bahwa tidak terjadi kesalahan dalam algoritma maupun penulisan kode program. Keluaran hasil perhitungan dari program simulasi juga dibandingkan dengan data hasil percobaan penelitian terdahulu untuk melihat keakuratan model termodinamika dalam memprediksi komposisi CH4, CO, CO2, dan H2. Program simulasi kesetimbangan termodinamika non-stoikiometri untuk proses gasifikasi biomassa dapat memprediksi komposisi gas produser dengan tingkat keakuratan yang cukup baik serta dapat dijadikan sebagai media pembelajaran dalam mempelajari kesetimbangan termodinamika.
Gibbs free energy minimization method has been used in modelling the performance of a downdraft gasifier. The performance is represented by the composition of resulting gas. Sixteen gases considered are H2, CO, CH4, H2O, CO2, N2, C2H2, C2H4, C2H6, NO, NO2, N2O, HCN, NH3, H2S and SO2. The simulation is carried out making used of EXCEL. The result showed that the predicted value of model fit reasonably well with experimental data. The model was also used to investigate the influence of biomass composition, oxidant ratio and composition of oxidizing agent to composition of the resulting gas. Three kinds of biomass considered are oil palm shell,oil palm frond and empty fruit bunch. The oxidant ratio simulated is varied from 0 to 1 while composition of oxidizing agent is varied from 21% - 100% oxigen. The simulation result showed that those three parameters play an important role in gasification process which in combination can produce total H2 and CO up to more than 85%. Keyword : Gasification, modelling, downdraft gasifier, Gibbs free energy minimization
Formic acid pulping of oil palm frond was conducted to study the influence of process variables (formic acid concentration, hydrogen peroxide concentration, and pulping time) on the properties of pulp produced (yield pulp and lignin content). A second order polynomial model consisiting of three independent process variables was found to accurately describe the formic acid pulping of oil palm frond. The propose equations reproduce the experimental results for the dependent variables with erros less than 5% for both yield dan lignin content. The most influential factor on yield pulp was formic acid concentration. Whereas, the cooking time has greater influence on lignin content. Keywords: formic acid, lingocelulose, pulping, pulp organosolv, oil palm fronds
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