Catalytic removal of biomass tars : olivine as prospective in-bed catalyst for fluidized-bed biomass gasifiers

With respect to global issues of sustainable energy and reduction of CO2, biomass is getting increased attention as a potential source of renewable energy. Among all the biomass conversion processes, gasification is one of the most promising. One of the major issues in biomass gasification is how to deal with the tar formed during the process. The average tar concentration in the exit gas from a fluidized bed gasifier is about 10 g m-3 (STP). The minimum allowable limit for tar, however, is highly dependent on the end user application. The preferable tar and dust loads in gases for engines must be lower than 10 mg m-3 (STP). Considerable efforts have been directed on tar removal from the fuel gas. Tar removal technologies can broadly be divided into two approaches; hot gas cleaning after the gasifier (secondary methods), and treatments inside the gasifier (primary methods). Primary methods are gaining much attention as these may eliminate the need for downstream cleanup. The objective of the present research is to find an appropriate catalyst that can be used as an active in-bed material for biomass gasification processes. Olivine is considered as prospective in-bed additive and catalytic activity of olivine is investigated in this thesis. The present research mainly includes fundamental aspects of catalytic tar decomposition, the kinetics and tar decomposition behavior over olivine. The performance of olivine under different gasification medium is also evaluated. Several characterization techniques have been utilized to understand the properties of olivine. Olivine used in this study, is a naturally occurring silicate mineral from Norway, containing oxides of magnesium, iron and silicon. Preliminary experiments are performed at ECN to compare the catalytic activity of olivine with dolomite. Total tar conversion of only 46% is observed at 900oC over olivine, which is lower than that of dolomite. Naphthalene is identified as one of the major tar compounds that contributes to more than 60% of total tar hence it is considered as a model biomass tar compound during this research. A fixed-bed reactor has been used to investigate catalytic decomposition of naphthalene over olivine. It is observed that pre-treatment of olivine with air at 900oC, could improve its activity towards tar removal significantly. Segregation of iron at the surface of olivine is observed due to pre-treatment. This results in a higher activity of olivine. Also the oxidation state of iron changes from 2 to 3. Crystalline hematite is formed, which increases with the increase in the pretreatment time. A naphthalene conversion of more than 81% is obtained over 10 h pretreated olivine, which is observed to be the optimum among the selected range of pre-treatment times. The effect of the presence of various reactive gases is investigated as well. Naphthalene conversion in gas mixture containing H2 and CO is found to be lower than that of only in presence of steam and CO2. The presence of H2 has a negative effect in terms of tar conversion. Steam and dry reforming reactions of naphthalene are mainly responsible for formation of valuable gaseous products such as H2 and CO. Cracking reactions lead to formation of other lower tars. Polymerization reactions form higher tars which further condense leading to soot formation. Olivine shows an attrition resistance, which is higher than that of sand and dolomite. The properties of olivine mentioned above make it a prospective candidate as an in-bed tar removal catalyst for fluidized-bed biomass gasifiers

Proses Komunikasi Interpersonal Ibu Yang Bekerja Dalam Pembentukkan Sikap Konatif Anak

Penelitian ini dilakukan untuk mengetahui bagaimana proses komunikasi interpersonal ibu yang bekerja dalam pembentukan sikap konatif anak. Seorang ibu yang bekerja yang memerlukan management waktu yang baik, agar dapat membagi waktu dan menyeimbangkan antara urusan pekerjaan dan keluarga.Penelitian ini dikaji berdasarkan delapan elemen komunikasi menurut Joseph A. DeVito, dan menggunakan metodologi studi kasus single case dengan teknik analisis data Miles dan Huberman. Hasil penelitian menunjukkan cara pengkomunikasian pesan yang ingin disampaikan oleh ibu yang bekerja kepada anak dalam membentuk sikap konatif. Sikap konatif adalah tahapan sikap dimana seseorang melakukan apa yang telah diketahuinya. Meskipun penyampaian pesan dilakukan secara personal, tetapi penerimaan pesan tersebut dapat diterima berbeda sesuai dengan hal-hal yang mempengaruhi pemikiran dan pandangan lawan bicara. Adapun cara yang dilakukan yaitu memberikan pengertian tentang pekerjaan ibu, memberikan kebebasan berpendapat, mengajarkan anak untuk selalu bersyukur dan berusaha, mendukung prestasi anak, memberikan tanggung jawab dalam menjaga keutuhan keluarga, dan membina hubungan yang dekat dengan anak

Evaluation of Petroleum Ether Extracts of Some Medicinal Plants Against Root Knot Nematode on Soybean

ABSTRACT: The petroleum ether extracts of some medicinal plants Tectona grandis, Mussendra globra, Xylosoma longifolia, Ocimum sanctum and Melia azedarach were tested as seed soaking on soybean for pot experiment. The seeds were soaked in 100 ppm concentration for 24 hours and dry in sun light and seedling was done in sterilized soil. After proper inoculation of J2 of root knot nematode Meloidogyne incognita, different observation were taken after 75 days of inoculation and found that plants treated with petroleum ether extracts of M. azedarach were shown much improvement in plant growth rate and reduction in disease incidence when compared with other treated plants. Petroleum ether extracts of Tectona grandis was found least effective when compared with untreated but inoculated one

Electronic Resources in Health Care

Health is the prime desire of man and history records the efforts of men and nations to healthy status. In recent years unprecedented growth has occurred in the business of providing health and medical care to our populations. Under such circumstances information technology has emerged as boon to provide health care information in CD-ROMs, in the form of virtual libraries, Internet, etc

Computer Aided Teaching Packages

Having recognized the importance of education and the teaching methodology, which plays a vital role, in the teaching-learning process in the modern electronic age, an attempt has been made in this paper to explore some of the important electronic resources, which aid in the teaching-learning process

Types of Resources Emerging Trends

The Paper examines in brief the various resources being used from ancient to the Modern age, where information technology is influencing our every days life. An attempt has been made to compare the conventional book with that of e-book which is of recent origin

Hubungan Persepsi Pengguna Layanan Tentang Mutu Pelayanan Unit Rawat Inap (VIP) Gryatama dengan Minat Pemanfaatan Ulang di BRSU Tabanan Tahun 2013

Unit rawat inap VIP (Gryatama) merupakan ruang perawatan bagi pasien umum BRSU Tabanan yang membayar dengan biaya sendiri. Selama 3 tahun terakhir terjadi penurunan jumlah pasien rawat inap, khususnya pada pasien umum. Selain itu tingkat kepuasan pasien (sebagai pengguna layanan) terhadap mutu pelayanan di unit rawat inap VIP (Gryatama) belum mencapai standar minimal yang telah ditetapkan berdasarkan Keputusan Menteri Kesehatan Nomor 129/Menkes/SK/II/2008 yaitu 90%. Tujuan penelitian ini adalah untuk mengetahui hubungan persepsi pengguna layanan tentang mutu pelayanan unit rawat inap VIP (Gryatama) dengan minat pemanfaatan ulangnya. Penelitian ini termasuk penelitian cross sectional. Instrumen penelitian menggunakan kuisioner pada 65 orang responden yang merupakan pengguna layanan unit rawat inap VIP (Gryatama) BRSU Tabanan. Sampel dipilih dengan menggunakan metode proportional stratified random sampling. Data yang terkumpul diolah dan dianalisa secara kuantitatif dengan metode univariat dan bivariat menggunakan uji chi square test . Signifikansi ditentukan dengan nilai p < 0,05. Hasil penelitian menunjukkan bahwa pengguna layanan terdiri dari 36,9% pasien dan 63,1% keluarga pasien. Karakteristik dari pengguna layanan adalah sebesar 50,8% perempuan, 26,2% berusia 40-49 tahun, 50,8% berpendidikan terakhir SMU, 23,1% bekerja sebagai PNS, serta 43,1% berpendapatan kurang dari 1 juta. Variabel yang berhubungan dengan minat pemanfaatan ulang pelayanan unit rawat inap VIP (Gryatama) BRSU Tabanan adalah persepsi tentang bukti fisik (p - value : 0,000), kehandalan (p – value : 0,000), daya tanggap (p – value : 0,010), jaminan (p – value : 0,002), dan empati (p – value : 0,000). Untuk meningkatkan minat pemanfaatan ulang pelayanan diperlukan peningkatan mutu pelayanan di unit rawat inap VIP (Gryatama). Peningkatan mutu pelayanan dapat dilakukan dengan meningkatkan kerjasama dari seluruh staf agar dapat mencapai target pada standar mutu yang telah ditetapkan di BRSU Tabanan. Sedangkan untuk meminimalisir persepsi yang tidak baik pada dimensi jaminan kelancaran pelayanan (assurance) perlu dilakukan penambahan jumlah staf administrasi dan membuka loket pendaftaran lebih awal untuk mencegah timbulnya antrian panjang yang menjadi permasalahan di BRSU Tabanan

Monthly changes of collembolan population under the gradients of moisture, organic carbon and nitrogen contents in a sub-tropical forest soil, Manipur.

Population study of collembola for one calendar year was made in relation with moisture, organic carbon and nitrogen contents of a sub-tropical forest floor upto 0-10 cm. soil layer. Soil moisture content played important role and developed a significant correlation (p>0.01) with the monthly population density of collembola. With increase carbon and nitrogen contents also observe increase population density indicating collembola’s active participation in the release of these two nutrients from litter through decomposition and its incorporation in soil fertility.Â