Wirawan, IKetutGede (2014) Pembakaran Premixed Minyak Nabati Pada Perforated Burner. Doctor thesis, Universitas Brawijaya.
Abstract
Perilaku pembakaran premixed minyak nabati diteliti secara eksperimen pada peforated burner. Minyak nabati yang digunakan adalah minyak kelapa murni maupun hidrolisis, minyak jarak pagar dan minyak biji kapok. Api yang terbentuk di ujung burner diberi 2 (dua) perlakuan yaitu: pertama api kontak dengan udara ambien, kedua api tidak kontak dengan udara ambien. Penelitian dilakukan pada berbagai equivalence ratio. Api perforated dan Bunsen sekunder terbentuk pada minyak kelapa murni dalam campuran miskin. Pada equivalence ratio (φ) meningkat, kecepatan pembakaran (SL) menurun dan api perforated mulai menghilang di φ = 0,88. Api Bunsen sekunder berlangsung di hilir api berlubang dari φ = 0.73 dengan SL lebih rendah dari api perforated yang juga menurun dengan meningkatnya φ. Tanpa gliserol, api perforated mulai berlangsung pada φ sedikit lebih besar dengan SL menjadi lebih tinggi. Maksimum SL masih terjadi pada campuran miskin yang lebih tinggi dari api heksadekana tapi hampir sama dengan api etanol. SL cenderung menurun dengan meningkatnya φ. Api masih stabil bahkan dalam bentuk api Bunsen sekunder sampai campuran sangat kaya. Ketika api terisolasi dari udara ambien SL api perforated mencapai maksimum dan bahkan lebih tinggi dari etanol pada campuran yang sangat miskin (φ = 0. 34). Ketika φ meningkat maka SL menurun dan api perforated menghilang pada φ = 0,56 sedangkan api Bunsen sekunder mulai berlangsung di hilir api perforated dari φ = 0.43 dengan SL cenderung meningkat mengikuti tren yang heksadekana. Api mulai punah ketika φ hampir satu atau lebih. Ketika gliserol dihilangkan dari minyak api perforated mulai terbentuk dari φ = 0,60 dengan SL lebih tinggi dibandingkan api dengan gliserol bahkan lebih tinggi dari etanol. SL menurun dengan meningkatnya φ. Api masih stabil dalam bentuk api perforated sampai campuran menjadi sangat kaya (φ = 1,78). Pembakaran premixed dari jarak minyak pagar (jatropha curcas) dibentuk equivalence ratio (φ) 0,310-1,548. Api perforated dan Bunsen sekunder terbentuk pada φ = 0,310-0,346. Campuran dengan φ = 0,355-1,548 terbentuk Bunsen ujung terbuka dan api triple. Jantropha curcas mengandung asam lemak tak jenuh lebih dari 55% yang mudah teroksidasi. Semakin banyak asam lemak memiliki ikatan rangkap maka minyak lebih rentan terhadap oksidasi yang menyebabkan ikatan molekul tidak stabil. Ketika api minyak Jatropha curcas diisolasi dari udara ambien sekitarnya, api perforated dan api Bunsen sekunder masih muncul di masing-masing φ = 0,355- 0,467 dan φ = 0,414-0,467. Pada φ = 0,355-0,375 api perforated mengalami lift off. Api Bunsen ujung terbuka dan api triple menghilang, namun api seluler berlangsung di φ = 0,489-0,585 dan api menjadi tidak stabil pada φ = 0,632-1,548. Fenomena ini menunjukkan bahwa stabilitas jarak pagar pembakaran minyak sangat dipengaruhi oleh udara ambien. Api minyak biji kapuk ( KSO ) api pada perforated burner dipelajari pada berbagai equivalence ratio. SL maksimum api perforated terjadi pada campuran yang sangat miskin adalah antara api heksadekana dan etanol di stoikiometri . Api perforated mengalami lift off pada φ = 0,32-0,34 . Peningkatan φ = 0,36-0,44 menyebabkan penurunan kecepatan pembakaran api perforated. Secondary Bunsen api terbentuk dari φ = 0,40-0,53 dengan penurunan kecepatan pembakaran . Ketika φ meningkat menjadi φ = 1,07 , api Bunsen dengan ujung terbuka terbentuk dengan penurunan kecepatan pembakaran. Api terisolasi dari udara sekitarnya pada φ = 0,30-1,07 . Pada φ = 0,30-0,31 api perforated mengalami lift off . Ketika φ ditingkatkan, api perforated terjadi pada φ = 0,32-0,40 diikuti oleh api Bunsen sekunder . Hal ini dapat dilihat bahwa SL api perforated pada campuran sangat miskin yang hampir sama dengan api etanol dan lebih tinggi dari api heksadekana pada stoikiometri . Peningkatan φ = 0,32-0,40 menyebabkan kecepatan pembakaran api perforated dan Bunsen sekunder menurun . Pada φ = 0,40-1,07 api perforated dan Bunsen sekunder menjadi tidak stabil dalam bentuk api seluler dan kepunahan . Sekali lagi , ini menunjukkan bahwa gliserol memerlukan sejumlah besar udara untuk pembakaran sehingga api stabil dalam campuran sangat miskin.
English Abstract
Premixed combustion behavior of vegetable oils studied experimentally on peforated burner. Vegetable oil was used coconut oil and hydrolysis, jatropha curcas oil and kapok seed oil. Flame formed on the burner tip was given two (2) treatments: first, flame was in contact with ambient air, the second flame was not in contact with ambient air. The study was conducted on a wide range of equivalence ratios. Perforated and secondary Bunsen flame formed on pure coconut oil at a lean mixture. As equivalence ratio,φ is increased burning velocity,SL of perforated flame decreases and the flame started to disappears at φ= 0.88. The secondary Bunsen flame takes place at the downstream of perforated flame from φ=0.73 with SL lower than that of perforated flame which also decrease with increasing φ. Without glycerol, perforated flame start to take place at a slightly larger φ with SL became higher. Maximum SL still occurs at lean mixture that is higher than that of hexadecane but nearly the same as that of ethanol. The SL tends to decrease with increasing φ. The flame is still stable even in the form of secondary Bunsen flame until the mixture is very rich. When the flame is isolated from ambient air the SL of perforated flames reached the highest and even higher than that of ethanol at very lean mixture (φ =0. 34). As φ is increased the SL decreases and the perforated flame disappear from φ =0.56 while the secondary Bunsen flame starts to take place at the downstream of perforated flame from φ =0.43 with SL tends to increase following the trend of that of hexadecane. The flame starts to extinct when φ is nearly one or more. When the glycerol is removed from the oil the perforated flame start to form from φ =0.6 with SL higher than that with glycerol even it is higher than that of ethanol. The SL decreases with increasing φ. The flame is still stable in the form of perforated flame until the mixture become very rich (φ =1.78). Premixed combustion of jatropha curcas oil was formed equivalence ratio (φ) from 0.310 to 1.548. Perforated and secondary Bunsen flame were formed at φ = 0.310 to 0.346. Mixture with φ = 0.355 to 1.548 formed open tip Bunsen and triple flame. More than 55% jantropha curcas contain unsaturated fatty acids which are easily oxidized. The more it has double bonds the more susceptible to oxidation which causes unstable molecular bonds. when Jatropha curcas oil flame was isolated from surrounding ambient air perforated flame and secondary Bunsen flame still appears at φ = 0.355 to 0.467 and φ=0.414 to 0.467 respectively. At φ = 0.355 to 0.375 perforated flame is lifted off. The Bunsen open tip and triple flame are disappeared, however, cellular flame takes place at φ = 0.489 to 0.585 and flame become unstable at φ = 0.632 to 1.548. This phenomenon indicates that the stability of jatropha curcas oil combustion is strongly influenced by ambient air. Kapok seed oil (KSO) flame on the perforated burner at various equivalence ratios is studied. The maximum SL of perforated flame occurred at a very lean mixture is between that of hexadecane and ethanol flame at stoichiometric. Perforated flame lifts off at φ = 0.32 to 0.34. The increase of φ from 0.36 to 0.44 decreases perforated flame burning velocity. Secondary Bunsen flame is formed from φ = 0.40 to 0.53 with declining burning velocity. When φ increased to φ = 1.07, Bunsen flame with open tip were formed with declining burning velocity The flame isolated from the surrounding ambient air at φ = 0.30 to 1.07. At φ = 0.30 to 0.31 of perforated flame lifts off. When φ increases the perforated flame occurs at φ = 0.32 to 0.40 followed by secondary Bunsen flame. It could be seen that SL of perforated flame at very lean mixture almost equal to that of ethanol flame and higher than that of hexadecane flame at stoichiometry. Increasing φ from 0.32 to 0.40 causes a burning speed of both perforated and secondary Bunsen flame decreases. At φ = 0.40 to 1.07 perforated and secondary Bunsen flame becomes unstable in the form of cellular and extinction flame. Once again, this indicates that glycerol requires a large amount of air to burn so the flame is stable in very lean mixtures.
| Item Type: | Thesis (Doctor) |
|---|---|
| Identification Number: | DES/621.436 1/WIR/p/061402165 |
| Subjects: | 600 Technology (Applied sciences) > 621 Applied physics > 621.4 Prime movers and heat engineering |
| Divisions: | S2/S3 > Doktor Teknik Mesin, Fakultas Teknik |
| Depositing User: | Budi Wahyono Wahyono |
| Date Deposited: | 29 Apr 2014 11:05 |
| Last Modified: | 29 Apr 2014 11:05 |
| URI: | http://repository.ub.ac.id/id/eprint/161051 |
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