生物柴油中酸值检测方案(自动电位滴定)

NTIA-07025 KMApplication Note Petroleum Acid number of Bio Diesel (BDF) Automatic Potentiometric Titrator Acid-base titration (non aqueous) JIS K 2501 IP 177 Standards ASTM D 664 GOST 29255 ISO 6619 1. Abstract Quality control of bio diesel fuel (BDF) on acid number is important since thenumber increases when the fuel itself deteriorates or BDF in production in line is notconforming. The acid number of BDF is measured according to JIS， ASTM or ISO standards bypotentiometric titration with 0.lmol/L potassium hydroxide 2-propanol solution untilthe endpoint is found on titration curve. The acid number of bio diesel fuel is calculated from the titration volume ofpotassium hydroxide 2-propanol solution consumed in reaching the endpoint. 2.Reference 1))JIS K 2501 Test Method for Neutralization number-Petroleum productsand lubricants 2)ASTM D 664 Standard Test Method for Acid Number of Petroleum Productsby Potentiometric Titration 3)ISO 6619 Petroleum products and lubricants-Neutralization number一Potentiometric Titration method 3. Cautions in measurement 1))Repeated measurement lowers sensitivity of glass electrode， and thus requiresregeneration process for the electrode each time a measurement is finished.To regenerate the electrode， dip it in an alcohol solution once for cleaning， andthen dip it in pure water for 10 ~ 60 min. (depends on how much contaminated)2) The standard concentration of potassium hydroxide 2-propanol solution is0.0005mo1/L or less..Adjust it to the standard level from time to time. 上海市漕溪路222号航天大厦北楼902室网址： http：//kem.instrument. com.cn 4. Post-measurement care After a series of measurements for the day is over， be sure to regenerate theelectrode once for all according to the preceding“3. Cautions in measurement”. 5. System configuration Main unit： Automatic potentiometric titrator (preamplifier： STD) Electrodes： (* mark shows standard supplied item) *Glass electrode H-171[No 98100H171] * Reference electrode R-173 N 98100R173 (Junction liquid： 3.33M-potassium chloride solution) * Temperature compensation electrode T-171 LN 98100T171] 6.Reagent Reagent： 0.lmo1/L Potassium hydroxide 2-propanol solution (f=1.000) Mixed solvent： Toluene： Water： 2-propanol(500：5：495) 7.Measurement procedure -Pretreatment- 1) Transfer 120mL mixed solvent to a 200mL beaker. 2) Perform a blank test， and obtain the blank level. Measurement- 1))Transfer approx.20g sample liquid to a 200mL beaker. 2)Add 120mL mixed solvent. 3)Titrate with 0.lmo1/L potassium hydroxide 2-propanol to obtain acid number. 8.Formula Total oxidation (mg/g) = (EPl- BLl)×TF×Cl×K1/ SIZE EPI Titration volume(mL) BLl Blank level (0.00mL) TF Reagent factor (1.00) Cl Concentration conversion coefficient ( 56.1 g/mL) (equivalent to potassium hydroxide in 1mL of 1mo1/L potassium hydroxide2-propanol solution) Kl Unit conversion coefficient(0.1) SIZE Sample size (g) 上海市漕溪路222号航天大厦北楼902室网址： http：//kem. instrument. com.cn 9. Example of measurement -Ambient condition- Room temperature ： 24 ℃ Humidity ： 78% Weather ： Rain (The below data and titration curve are printed out when titrated by AT-510 unit.) -Titration parameter- -Titration curve- Model ： AT-510 Serial No. ：NZB52534 Method No. ： 01 Titr.mode ： Auto Intermit Titr.form ： EP Stop [Titration parameter」 Form ： EP StopAPB No. ：1Unit No. ：1Detector No. ：1Unit ： pHMax. Volume ：220.0mLWait Time ：0sDirection ： Auto [Control parameter] End Point No.：：1End sense ：AutoEnd Point Area ：OffSeparation ： Off0ver Titr.Vol. ：0mLGain ：1Data samp. Pot.： 4.0mVData samp. Vol.：0.5mLStability ： 0.5mV/sDelay Time ：00sLimit Time ：330s [Result parameter] Calc.Type ： Sample Conc. 1 ： Set C01= (EP1-BL1)*TF*K1*C1/SIZE Unit ： mg/gEP No. ：1 Temp. Comp. ：0ff C1(mg/mL) ：56.1K1 ：0.1 [Titr. constant] TF ： 1.00 [Blank list] Blank1 ：0.00 ***Result*** Sample No. ： 01-01 Date9：2007/06/25 14：34Sample ID ： Sample Method No. ： 01 Method Name ： Auto IntermitTitr.Reagent Name ： 0.1M-K0H Titr.time ： 00：12：24 Size ：119.994 g Conc-1 ：00.6301mg/g End point-1Volume ：2.2456mL Potential： 12.94pH 3.00 [PH] 16.00 0.000 4.300 [mL] 《Titration parameter> Form： titration form /APB No.： number of power burette / Unit No.： APB Unit File numberDetector No.： detector number / Max Volume.： of titration / Wait Time： before titration startsDirection.： of titration《Control parameter>End Point No.： total EPs / End sense： direction / End Point Area： EP detection areaSeparation： separated potential / Over Titr.Vol.： over titration / Gain： sensitivity of signalData samp.Pot.： potential change for data sampling / Data samp.Vol.： titration change for data samplingStability： stability level /Delay Time： before stability check / Limit Time： for stability check《Result parameter>Calc.Type： calculation type / Conc.1： concentration formula 1 / Unit： of calculated resultsEP No. EP number / Temp.Comp.： temperature compensation /C1(mg/mL)： concentration conversion coefficient K1： unit conversion coefficient / TF： factor of reagent /Blank1： blank level 1 京都电子工业株式会社-可睦电子(上海)商贸有限公司 上海市漕溪路222号航天大厦北楼902室网址： http：//kem.instrument.com.cn —-Measurement resultsS- n Sample(g) 19.994 Titrated(mL) 2.246 Acid number(mg/g) 123 19.99419.996 2.239 2.232 4 19.991 2.224 Statistics of acid number MeanSD RSD 0.6275 mg/g0.0025 mg/g0.3921 % *The data were obtained from 5 tests of the same sample. *Red underline shows the data from page 3/4. 10. Summary The acid number is potassium hydroxide in mg consumed in neutralizing one (1)gram of free fatty acid. The above example shows a good result of repeatability with less than 0.4% RSD(relative standard deviation) by the automatic potentiometric titrator. The acid number of BDF can be analyzed by any of the following titration systems. 【AT-610】 【AT-510】 【AT-500N-1】 Awarded Supreme Technology fromKyoto City ·Compact and cost performancemodel · Low cost and high performance ·Easy view with back light LCD 。Easy key entry by touch panel oflarge color LCD (8-inch wide) ·PC card expands data memory forconvenience and versatility. · GLP/GMP conformed model · Simultaneous titration in parallel· Both potentiometricand KarlFischer moisture titration(coulometric"volumetric)can beperformed at a time. KM KYOTO ELECTRONICS MANUFACTURING CO.，LTD. Overseas Division： Yamawaki Bldg 9F，4-8-21 Kudan-minami，Chiyoda-ku， Tokyo 102-0074 JAPAN Phone：+81-3-3239-7333， Fax： +81-3-3237-0537 Head Office： 56-2 Ninodan-cho，Shinden，Kisshoin，Minami-ku， Kyoto 601-8317 JAPAN Phone：+81-75-691-4122，Fax： +81-75-691-9961 URL： http：//www.kyoto-kem.com 京都电子工业株式会社-可睦电子(上海)商贸有限公司 上海市漕溪路222号航天大厦北楼902室 电话：021-54488867 电邮： kemu-kem@163.com 网址： http：//kem.instrument. com. cn 京都电子工业株式会社-可睦电子(上海)商贸有限公司电话： 电邮： kemu-kem@ comTIA-Ver. 京都电子工业株朱会社-可睦电子(上海)商贸有限公司电话： 电邮： kemu-kem@ comTIA-Ver.