Penyingkatan Waktu Penyalaan Kompor Briket Batubara

Penelitian pembakaran briket batubara untuk mempersingkat waktu penyalaan telah dilakukan dengan memanfaatkan briket promotor bentuk bola yang mengandung oksigenat etil asetat sebanyak 15% berat briket yang berfungsi sebagai penyedia oksigen secara internal dalam material briket karena ketidakcukupan oksigen saat briket promotor mengalami devolatalisasi (fungsi kinetika kimia) dan sebagai penguat terjadinya perpindahan panas konveksi dari bara api pada briket promotor ke briket pemasakan yang diletakkan di sekitarnya karena menambahkan cekukan (dimples) pada permukaan briket promotor berbentuk bola (fungsi perpindahan panas). Penelitian dilakukan dengan menempatkan briket promotor di lapis pertama (atas) di atas dua lapis briket pemasakan dalam kompor briket. Penelitian ini bertujuan meneliti efek penambahan, loading dan bentuk briket promotor (bentuk bola, bola dengan dimples) terhadap waktu penyalaan. Penelitian ini menggunakan udara dengan kecepatan superfisial yang diukur pada kondisi dingin sebesar 1,1 m/s. Penelitian juga dilakukan dengan menempatkan briket promotor berbentuk bola dengan dimples di lapis kedua dengan loading 25% dari 3 lapis briket yang digunakan dengan lapis pertama, sisa lapis kedua dan lapis ketiga diisi briket pemasakan. Parameter kecepatan superfisial udara yang diukur pada kondisi dingin divariasikan pada harga-harga 0,6, 1,2 dan 1,8 m/s untuk melihat pengaruhnya terhadap waktu penyalaan. Hasil penelitian menunjukkan bahwa adanya briket promotor mempercepat waktu penyalaan briket pemasakan hingga 35 menit. Semakin besar loading briket promotor dalam kompor, waktu penyalaannya akan semakin cepat pula. Untuk loading 100%, 75%, 50% dan 25% waktu penyalaan masing-masing adalah 18, 22, 23 dan 25 menit. Dalam hal efek bentuk briket promotor, bentuk bola dengan dimples memiliki waktu penyalaan lebih cepat daripada bentuk bola dengan waktu penyalaan masing-masing 11 menit dan 18 menit. Jadi, waktu penyalaan semakin singkat dengan loading briket promotor semakin besar dan dengan menggunakan briket promotor berbentuk bola dengan cekukan daripada tanpa cekukan. Hasil penelitian dengan menempatkan briket promotor berbentuk bola dengan dimples menunjukkan bahwa waktu penyalaan pada kompor dengan kecepatan superfisial udara 0,6 dan 1,2 m/s hampir sama sebesar 8 menit, sedang dengan kecepatan superfisial 1,8 m/s sebesar 13 menit. Variasi kecepatan superfisial memberi 2 efek yang berlawanan yang bekerja bersamaan terhadap perpindahan panas konveksi yaitu efek turbulensi dan efek quenching. Efek turbulensi mempercepat penyalaan, sedang efek quenching memperlambat penyalaan. Diperkirakan bahwa kecepatan superfisial 1,8 m/s memberi efek quenching lebih besar dibanding efek turbulensi sehingga waktu penyalaan lebih lama

The Use of a Jet Column with Different Nozzles as a Reactor for Biodiesel Reaction with Crude Palm Oil as Feedstock

Biodiesel may be produced by trans-esterification reaction of vegetable oil, which transforms triglycerides into alkyl esters as biodiesel and glycerol as a byproduct, in the presence of an alcohol reactant and a acid or base catalyst. The major obstacle of preventing biodiesel commercialisation is low mass transfer rates from methanol into oil phase to achieve high yield due to large difference in fluid viscosities, i.e. low viscosity methanol and high viscosity oil. Many techniques have been proposed to overcome this obstacle, most of which involve high mole ratio of methanol to triglycerides exceeding 6, but none of them utilised fluid mechanic techniques to fix up the obstacle. The present research adopts a finding in fluid mechanic field that notched and tabbed nozzles are capable of intensifying shear stress between 2 different flows, which consequently increases the contact areas of the flows considerably. For this purpose, in the present research, a jet column was utilised as a reactor where the mixture of reactants, i.e. crude palm oil (CPO) and methanol with catalyst NaOH were recirculated and injected downward vertically into the reactor column from a nozzle at the top of reactor. The type of nozzles and the mole ratio of methanol to CPO were varied (3.75:1; 4.5:1; 5.25:1 and 6:1) to investigate their effects on yield and conversion of the reaction conducted for 60 minutes at temperatures 53-58oC. Nozzles used were notched, tabbed and conventional circular nozzles for comparison. The highest conversion and yield of biodiesel were achieved at mole ratio 6:1 attaining respectively 87.2% and 96.8% using notched nozzle, 87.8% and 96.6% using tabbed nozzle and 71.2% and 75.1 % using circular nozzle for comparison. Therefore, using notched and tabbed nozzles can reduce the excess of methanol reactant thus saving its separation cost while producing high yield of biodiesel

Faktor-Faktor yang Mempengaruhi Impor Indonesia, 2000.I-2008.I

The aim of this research are to enquiry the influence of exchange rate rupiah to USD, Gross Domestic Product (GDP), and world oil price toward import of Indonesia during 2000.I-2008.I. The research methods are descriptive and quantitative analyses using secondary data. The analysis tool is path analysis to show direct and indirect influences of Indonesia's import. This research also uses t-test to show partial influence and F-test to know together influence. Between those three variables, world oil price is the most influence variable of Indonesia's import

Faktor-Faktor yang Mempengaruhi Partisipasi Masyarakat terhadap Pembangunan di Kabupaten Banyumas

The aims of the research are: to find out the condition of the people participation, income distribution, education level, economic growth, and government expenditure, and also to find out and analyze the effects income distribution, education level, economic growth, and government expenditure to the people participation in Banyumas Regency. The data are secondary data that covered: the people participation, income distribution, education level, gross regional domestic product, and government expenditure in Banyumas Regency. The method analysis are tabulation and multiple regression analysis model. The result of 1999–2006 period analysis shows: (1) The everage growth of people participation on 8,29%, economic growth on 3,49%, government expenditure on 20,44%, income distribution on 2,57%, and education level on 4,93% for every year, (2) The effect of the four variables above in people participation have significant effect but in partial only government expenditure variable have significant effect on 5%. Therefore, it is suggested that Banyumas Regency Government should be to attended and give an real example to increase the people participation, economic growth, income distribution, and the level of education with the government expenditure

Kontribusi Besar Pendapatan Wanita Pemulung terhadap Pendapatan Keluarga (Studi Kasus pada Wanita Pemulung di TPA Gunung Tugel Kabupaten Banyumas)

The Purposes of this study are to determine the contribution of woman rollers garbage's income toward income of family, degree of poverty, and degree of welfare on the rollers garbage's family. A respondent on this study are women rollers garbage that have already married and have children with the amount as many as 25 percent or 22 person of woman rollers garbage. The tool of analysis that used are tabulation for determine contribution of income, double linear regression to determine factors that influence toward income and income ratio with the poverty line from the result of Statistics Central Department (BPS) on 2007 to recognize degree of poverty and to determine degree of welfare's ratio income with the needed of dialy life on October 2008 in Banyumas regency. The results of study show that: a. Contribution of woman roller garbage's income toward income of family, is included in the big scale with the 61.98% average.b. The result of F-test and t-test in factors of : age, education, experience for rolling garbage and the amount of children, have significant toward income of roller garbage. Which the rank is from the biggest influenced of them are the amount of children, education, age and experience for rolling garbage.c. Average degree of welfare of rollers garbage family is stated above absolutes poverty line as 155.58%d. But however degree of welfare of woman roller garbage's family is still under the welfare, its still reach 33.25 percent.From that study, implication appears toward the rollers garbage, they should be increase their creativity and toward other side of rollers garbage should be provide the different place of organic garbage and non organic one on TPA, and also give such kind of health service and creativity education

Improving the quality of pyrolysis oil from co-firing high-density polyethylene plastic waste and palm empty fruit bunches

This study aimed to produce and improve the quality of pyrolysis oil as a source of bioenergy that is made by mixing palm empty fruit bunch (EFB) with high-density polyethylene (HDPE) plastic waste. The slow co-pyrolysis method was employed, and HDPE waste and EFB were fed into the pyrolysis reactor at HDPE amounts of 0, 10, 25, 50, 75, and 100% by weight. The pyrolysis oil product was obtained by co-firing EFB with HDPE using the slow co-pyrolysis method in a fixed bed reactor at 500°C with a flow rate of 750 mL/min and a heating rate of 5°C/min. The chemical compositions of pyrolysis oil were analyzed by gas chromatography-mass spectroscopy. A pyrolysis oil produced by HDPE 100 wt.% was dominated by the chemical compounds of phenols, aromatics, aliphatic, and acids, while for EFB 100 wt.% was dominated with aldehydes, acids, phenols, furan and aliphatic. The addition of HDPE reduced the amount of pyrolysis oil yield, increased the pH, reduced the viscosity, and reduced the oxygen content of the pyrolysis oil. These results proved that the HDPE affected the decrease in pyrolysis oil and the increase in gas production from co-firing HDPE and EFB using the slow co-pyrolysis method