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F351130341. Formulasi Dan Kinerja Asphaltene Dissolver Menggunakan Surfaktan Anionik Dari Minyak Sawit.
No full textAsphaltene merupakan golongan fraksi berat dari minyak bumi dan
diterminologikan sebagai komponen sangat aromatik yang mengandung
makromolekul heterosiklik tak jenuh dengan komponen utama yaitu karbon,
hidrogen, dan komponen minor lain seperti sulfur, oksigen, nitrogen, serta
akumulasi beberapa jenis logam berat seperti besi, nikel, vanadin, aluminium, dan
magnesium (Okafor et al. 2013). Keberadaan asphaltene di dalam minyak bumi
bukanlah sebagai molekul terlarut, melainkan sebagai nanopartikel yang dapat
membentuk agregat. Ketika terjadinya perubahan kondisi termodinamika selama
proses produksi minyak bumi, kestabilan nanopartikel akan terganggu sehingga
saling bertumbukan dan membentuk agregat yang terus tumbuh menjadi partikel
yang lebih besar, dari ukuran nano, mikron, sampai terbentuknya deposisi pada
daur hidup produksi minyak bumi seperti perforasi, tubing, downhole, dan
peralatan permukaan.
Proses deposisi asphaltene dapat terus terjadi selama proses produksi
minyak bumi sehingga jumlah endapan yang terbentuk semakin meningkat.
Terbentuknya deposisi asphlatene merupakan salah satu penyebab penurunan
produksi sumur minyak dan peningkatan biaya operasional produksi (Oseghale et
al. 2011; Li et al. 2014) serta menjadi masalah utama pada industri perminyakan
yang menyebabkan lambatnya proses produksi atau bahkan pemberhentian proses
produksi untuk menghilangkan asphaltene yang terdeposisi (Hasmi et al. 2012).
Salah satu upaya yang dapat dilakukan untuk mengatasi permasalahan
deposisi tersebut adalah melalui injeksi langsung asphaltene dissolver dengan
penambahan surfaktan. Surfaktan dapat berperan sebagai dispersant dan wetting
agent yang dapat terdispersi ke dalam molekul asphaltene dengan memecah
ikatan antar molekul asphaltene sehingga dapat menghambat pembentukan
kembali endapan asphaltene. Namun kebanyakan surfaktan yang digunakan
adalah surfaktan komersial dari bahan baku berbasis petroleum. Surfaktan ini
bersifat tidak terbarukan seiring dengan semakin berkurangnya cadangan minyak
bumi. Jenis surfaktan lain yang dapat digunakan adalah surfaktan anionik yang
berasal dari bahan baku nabati seperti metil ester sulfonat acid (MESA) dan metil
ester sulfonat (MES) dari minyak sawit.
Penelitian ini bertujuan untuk menghasilkan produk asphaltene dissolver
terbaik menggunakan surfaktan anionik yang berasal dari minyak sawit.
Disamping itu untuk mendapatkan informasi kinerja dari asphaltene dissolver
yang dihasilkan serta mendapatkan informasi kinerja aplikasi dari asphaltene
dissolver yang dihasilkan dengan mengetahui pengaruh suhu dan waktu kontak
terhadap kelarutan asphaltene.
Penelitian diawali dengan karakterisasi deposit asphaltene dan
karakterisasi surfaktan MESA dan MES. Selanjutnya dilakukan proses formulasi
asphaltene dissolver dengan tahapan awal yaitu pemilihan jenis pelarut terbaik
berdasarkan hasil derajat kelarutan tertinggi. Kemudian pemilihan jenis dan
konsentrasi surfaktan terbaik menggunakan surfaktan MESA dan MES dengan
konsentrasi masing-masing 0%, 0,5%, 1%, 3%, dan 5%. Pemilihan didasarkan
pada nilai kelarutan tertinggi dan tegangan antarmuka terendah. Asphaltene
dissolver terbaik yang dihasilkan dilakukan uji kinerja yang meliputi pengukuran
daya dispersi, desorpsi asphaltene dari batuan, wettability pada batuan, wetting
charateristic pada permukaan logam, dan uji filtrasi. Asphaltene dissolver yang
dihasilkan kemudian dilakukan pengujian kinerja aplikasi dengan melihat
pengaruh suhu dan waktu kontak terhadap derajat kelarutan asphaltene.
Dari hasil analisis formulasi dan kinerja yang telah dilakukan, asphaltene
dissolver terbaik yang diperoleh adalah campuran surfaktan MESA 1% dalam
toluena yang menghasilkan derajat kelarutan asphaltene sebesar 69,58% dengan
nilai tegangan antarmuka terendah yaitu sebesar 3,95x10-3 dyne/cm. Kinerja
asphaltene dissolver menunjukkan bahwa asphaltene dissolver yang dihasilkan
memiliki daya dispersi dan desorpsi yang baik dibandingkan toluena dengan nilai
dispersi sebesar 95,56% dan nilai desorpsi sebesar 93,16%. Asphaltene dissolver
yang dihasilkan dapat mengubah sudut kontak batuan dari 48,6o menjadi 80,89o.
Sudut kontak yang dihasilkan merupakan sudut kontak terbaik dibandingkan
dengan toluena. Uji wetting characteristic memperlihatkan kemampuan
asphaltene dissolver dalam meningkatkan sifat kebasahan pada permukaan logam
dengan pelepasan asphaltene sebesar 99,32% pada asphaltene dissolver dan
toluena sebesar 26,59%. Pada uji filtrasi menunjukkan bahwa asphaltene
dissolver yang dihasilkan tidak menimbulkan penyumbatan dengan nilai filtration
ratio (Fr) sebesar 1,14 yang berarti masih dalam rentang nilai <1,2.
Hasil analisis sidik ragam menunjukkan bahwa faktor suhu dan waktu
kontak secara signifikan berpengaruh terhadap derajat kelarutan asphaltene
dengan aplikasi asphaltene dissolver pada tingkat kepercayaan 95%. Derajat
kelarutan asphaltene meningkat seiring dengan meningkatnya suhu pemanasan
dan waktu kontak. Derajat kelarutan asphaltene tertinggi dihasilkan pada suhu
100 oC dengan waktu kontak selama 180 menit sebesar 99,38%
Formulasi Surfaktan Metil Ester Sulfonat sebagai Oil Well Cleaning
No full textOil productivity reduction may be due to plugging in the oil rock formations. The plugging may be caused by the deposition of paraffin, asphaltene, and scale. Problem caused by the presence of the precipitate is the rock formation can be oil wet so that oil permeability decreases. The problem can be solved by well cleaning technique with surfactant formula. Surfactant MES is a type of anionic surfactant which has ability to lower the interfcial tension, surface tension, and able to change the properties of rock from oil wet to become water wet. Surfactant MES formula for well cleaning requires carrier agent. In this study, diesel oil and metil ester were used as carrying agent. Aromatic solvents were also needed. Xylene and toluene has ability to dissolve asphaltene that deposites in formation. Surfaktan formulation for well cleaning was done with several stages, those are determine the SMES concentration and aromatic solvents concentration. Surfactant performance tests for oil well cleaning were thermal stability, phase behavior, and wettability. The surfactant formula which gave the best performance was SMES 3% in metil ester carrying agent with xylene 15% as additive
Formulasi Surfaktan MES Sebagai Acid Stimulation Agent untuk Lapangan Karbonat (Studi Kasus: Lapangan T)
No full textThe decrease of oil well productivity can be affected by the scale blockage and the conditions inside of the oil well. This problem can be solved by stimulating the oil well with an acid stimulation agent. This chemical solution contains of surfactant, brine, and acid. The surfactant reduces the interfacial and surface tension, the brine dissolves the surfactant, and the acid has a function as carbonate scale solvent. This research was conducted to find the formula of acid stimulation agent that gives the best performance to improve the oil well productivity. The materials used in this research were the oil well fluids that consist of formation water and crude oil from T oil field. The surfactants (MES and SMES) concentration used in this research was 0.5%, 1%, 1.5%, 2%; 3%, 4%, 5%, and 6% (w/w). HCl concentration added to surfactant solution were 5%, 10%, and 15% (w/w). At the last, 2% CH3COOH was added to this formula. The formula that gave the best performance was SMES 4% + HCl 5% + CH3COOH 2% with IFT value 6.74x10-2 dyne/cm and the solubility degree 20.7%. This formula has good resistance to high temperature of 90oC and has good capability of changing the core wettability to become more water-wet
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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