Presentation on theme: "Large Boilover experiments in Japan"— Presentation transcript:
1Large Boilover experiments in Japan Hiroshi KosekiNational Research Instituteof Fire and Disaster, JapanTomakomai, Japan
2AbstractsIn order to know boilover phenomenon in large tanks, large scale boilover experiments in a 5 m diameter pan using crude oil were conducted. Initial fuel thickness was 0.7m.To know repeatability we tested twice in the same conditions.About 80 minutes after ignition, large boilover was occurred. Radiation from fire increased about twenty times as much as that of steady burnings.Times to boilover were within our expecting which we obtained with smaller pans and other reports.
3Background Past boilover accidents in Japan We had twice boilover accidents in JapanＨｅａｖｙ ｏｉｌ C, Ｙｏｋｋａｉｃｈｉ，Ｏｃｔｏｂｅｒ １５, 1954(2) Crude oil, Ｎｉｇａｔａ，June 1６, 1964Ｎｉｇａｔａ, June 1964
4Earthquake damages in Oil facilities In Japan we have many earthquakes in JapanSometimes, oil tanks were damaged, and some were caught firesTwo Tomakomai fires in 2003 were reported by Mr. HiraiNigata earthquake damaged tanks and continued more than two weeks in 1964, and made boilover in crude oil tanks
5Recent Fire Tests in Japan Joint work among NRIFD, U. Tokyo and Oil company 20m pan fire testLarge crude oil fire tests in 20 m pan(1997)Boilover tests(1999)Tests were conducted inTomakomai, Hokkaido, Japan20m pan fire test
6Kinds of boilover Boilover: Fuel layer thickness is 0.55 m Clear hot zone (isothermal zone) is madeOur target: 1) normal boilover2) Effects of water existenceWater emulsion crude oil was burntSlopoverFrothoverThin-layer boilover: Fuel layer is very thin
7Mechanism of boilover High temperature zone was made after long burn, and then increase its width, Details were shown in many text books
15Temperature measurement Thermocouples were bedded along with pan pole
16Crude oilCrude oil we used, is equivalent to Arabian light crude oil supplied by Idemitsu Oil Co., which is most popular crude oil.That is, we bought from Idemitsu Hokkaido Refinary, in which large oil tank fires occurred in 2003.
17Distillation curve equivalent to Arabian light crude oil
21Results-Fuel and water temperature Hot zone was made and its temperature increase
22Hot zone regression rate, thickness, temperature vs time
23Conclusion Time to boilover Time to boilover can be estimated with fuel thickness because hot zone regression rate is known from many our data and real accidents.According to API data,we obtain these lines,and our data were withinthese lines.Time (hour)Fuel thickness (m)
24ConclusionAbout 70 minutes after ignition, we had boilover, and external radiation increased about 22 times as much as steady burning.We measured temperature inside the fuel, and found that there might be three steps1) no isothermal zone was observed2) Isothermal zone was made, but not high temperature3) Then, temperature of isothermal zone increased, and reached water layer
25ConclusionOur data support results of our small test and other group didData is open, anybody can use our data, because large boilover test is difficult to do so oftenPublication: Fire safety Journal vol.41, 2006Other information is availableContact me,