EMISSION MEASUREMENTS IN DUAL FUELED INTERNAL COMBUSTION ENGINE TESTS

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1 XVIII IEKO WORLD NGRESS etrology for a Sstanable Development September, 17, 006, Ro de Janero, Brazl EISSION EASUREENTS IN DUAL FUELED INTERNAL BUSTION ENGINE TESTS A.F.Orlando 1, E.Santos, L.G.do Val 3 1 PUC-Ro, Ro de Janero, Brazl, afo@mec.pc-ro.br W, S.Palo, Brazl, edgar.santos@mwm.com.br 3 PUC-Ro, Ro de Janero, Brazl, ldoval@mec.pc-ro.br Abstract: Dal feled engne test procedres and reslt nterpretaton are not avalable n the lteratre, Ths paper descrbes a methodology for calclatng the emsson mass flow rates, sng the chemcal reacton mass balance of the components. The expermental data were obtaned from tests made at the W dynamometer. Startng from basc prncples, the hydrocarbon () mass flow rate was related to molar concentraton throgh the moleclar mass and the mass flow rate, and compared to the avalable expressons n the EPA desel engne test standard. The dal fel model was establshed by a lnear combnaton for the hydrocarbon () eqvalent moleclar mass, when there s 0 % and 100 % natral n the fel. Fnally, the paper shows that, by a smlar methodology, the natral mass flow rate can be calclated from emsson measrements. Keywords: emssons, dal fel, chemcal reacton mass balance. 1. INTRODUCTION Desel feled engne tests n Brazl follow standard ABNT 05: [1]. olar concentraton of the components (ppm) are measred to wthn,5 % and are sed to calclate the emsson mass flow rates (g/kwh). These vales are compared to lmts stplated by the envronment legslaton, so that the engne can be approved for operaton. Becase of the fact that the emsson flow rates are not drectly measred, they mst be calclated from the measred vales of desel ( desel ) and ar ( ar ) mass flow rates, whch are avalable from [1]. Dal feled engne test procedre and reslt nterpretaton are not avalable n the lteratre, and reqres addtonally the natral ( ) mass flow measrement. Ths paper descrbes a methodology for calclatng the emsson mass flow rates, sng the chemcal reacton mass balance of the components. Becase ther mass flow rates are mch smaller than those for O, N and, a care had to be exercsed to nmercally evalate them wth mnmm dscrepancy. The expermental data were obtaned from 13 pont tests made wth W dynamometer.. BUSTION CHEICAL REACTION.1 Ar composton In ths methodology ar composton s calclated from emsson measrements and compared to the standard one, 1 % O and 79 % N, whch has an eqvalent moleclar mass of 8,84, as opposed to the real one of 8,97.. Desel composton An eqvalent desel composton was establshed from the ltmate analyss made by PETROBRAS (Brazlan ol company), resltng n C n H m S p, wth an eqvalent moleclar mass of 04,7, and n = 14,809, m = 6,96 and p = 0, Natral composton The chromatography molar composton was sed to calclate an eqvalent composton for the natral, resltng n, Cn ' H m' + xn. N + x., wth an eqvalent moleclar mass of 17,8606, and n = 1,113, m = 4,09, x = 0,0036 and x = 0, Exhast composton n a dry bass N The HORIBA emsson meter measres drectly the molar composton (y), respectvely for (%), NO x (ppm), (ppm), (ppm) and O (%)..5 Chemcal reacton eqaton a. C H y n m. S + ( g. O + h. N ) + c.( C H p + y. + y. + y + x. N + x. ) n' m' N NO. NOx + yo. O + d. H O + e. N x + f. SO where a, b, c, d, e, f, g and h wll be determned from chemcal reacton mass balance. Ar composton, g and h, wll be determned also from mass balance. (1)

2 3. EISSION ASS FLOW RATE CALCULATION 3.1 Basc eqatons The deal eqaton relates partal pressre (P ), mass (m ), moleclar mass ( ), absolte temperatre (T) and mxtre volme (V) for each component (NO x, and ) by the followng eqaton: 3. Emssons from desel felled engnes Table 1 shows the vale of C from [1], and the calclated moleclar mass from Eq. (9). Table 1 : Emsson eqvalent moleclar mass [1] R P. V = m.. T () where R = 8314,47 J/kmol.K s the nversal constant. Also, the molar fracton of component, can be expressed as a fncton of the mxtre pressre as : P x = (3) P m V P = x.. (4) R. T However, at the reference condtons P = Pa, and T = 73,15 K. Ths, m ( g / m V ) = x ( ppm). (5) Accordng to [1], the specfc mass (ρ ) s approxmately the same as for ar (ρ ar ), that at the same reference condtons has the vale of : ρ m V ρ = ar = 1,93 kg/m 3 (6) Combnng Eq. (5) and (6) and notcng that : m & + + = (7) desel ar Emsson C NO x 0, , , ,88 It can be seen that the test standard [1] calclates NO x as NO, as an pper lmt ( NO x = 46 ). moleclar mass calclated from [1] concdes wth ts actal vale ( = 8). For hydrocarbons () however, only desel lghter components are consdered, resltng n an eqvalent moleclar mass (13,88) less than for natral (17,8606). An eqvalent composton of CH 1,88 was then adopted as representatve of composton. 3.3 Emssons from dal feled engnes The methodology consders that nbrned hydrocarbons n the es come from two sorces, (a) Desel lghter components, from [1], wth,desel = 13,88, or CH 1,88, (b) Natral wthot and N, wth, = 17,565, or C 1,113 H 4,09. From Eq. (1), a fracton α of the desel natral mxtre wll not be brnt, or : ( a. CH + c C ) α. H (10) 1,88. 1,113 4,09 An eqvalent hydrocarbon composton can be wrtten as C r H s, where : ( g / h) = x ( ppm). C. ( kg / h) (8) C = (9) r =..1,113 (11) 1 s =.1,88 +.4,09 (1)

3 wth an eqvalent moleclar mass of : = 1.r + s (13) The lnear combnaton of ths methodology takes nto accont that when there s only desel n the fel, the hydrocarbon moleclar mass s 13,88 [1]. When there s almost natral n the fel [], the hydrocarbon composton s approxmately the same as natral. Therefore, a lnear nterpolaton s sggested for dal fel, based on the followng expresson, wth the help of Eq. (1) : desel a. = c. desel (14) Usng desel = 04,7 and = 17,8606, the followng expresson can be obtaned : easred mass flow rates (n kg/h) for desel ( desel ), natral ( ) and combston ar ( ar ). easred molar concentraton (y) n the es of (%), NO x (ppm), (ppm), (ppm) and O (%). From Eq. (1), the followng nkowns mst be calclated by solvng the system of eqatons : a, c, d, e, f, g and h. The followng 5 eqatons are the reslts of the chemcal reacton mass balance : C: a. n c.( n' + x ) = y + y + r. y + (16) H: a. m + c. m' = s. y +. d (17) =.11,461 (15) desel O:. g +. c. x =. y + y = +. y NO +. yo + d +. f x (18) The hydrocarbon moleclar mass can ths be calclated by Eq. (13), pon calclatng r and s from Eq. (11) and (1), wth the help of Eq. (15). An nterestng aspect of ths methodology s that NO x and mass flow rates are calclated the same way as when there s only desel n the fel, ths accordng to [1]. Ths hypothess s spported by an EPA report [3] that ndcates that the emsson factors for NO x and are almost the same from desel and dal fel, and mch hgher for from dal fel. In order to valdate ths methodology, a chemcal reacton mass balance s performed wth the expermental data obtaned from tests n a W dynamometer. 4. CHEICAL REACTION ASS BALANCE A 13 pont dynamometer test was sed to spply data to the chemcal reacton mass balance, whch was appled to Eq. (1). That means that the nmber of atoms n the reactants and n the combston prodcts mst be the same for C, H, S, O and N, whch spples 5 eqatons to be solved. The followng data mst be sppled : Desel composton and ts moleclar mass. Natral composton and ts moleclar mass. S: a. p = f (19) N:. h +. c. x = y + e (0) N NO x. Two more eqatons can be obtaned from desel, natral and ar flow rates measrements :. desel = (1) desel g h. ar desel + = () desel ar The ar moleclar mass can be calclated from the followng eqaton : ar g g + h h + g + h = (3). O. N Eq. (16), (17), (18), (19), (0), (1) and () can be solved teratvely for determnng a, c, d, e, f, g and h. Eq. (11) and (1), together wth Eq. (1) can be sed for calclatng r and s. A software (SOFT 1) was developed for the calclatons.

4 Table shows the valdaton of the methodology aganst the chemcal reacton mass balance and standard [1]. A 13 pont test was made at W, sng only desel as fel. It can be seen that the reslts are practcally the same, ths valdatng both methodologes, processed by SOFT 1. Table 3 shows the emsson mass flow rates for a 13 pont test at W, sng a converson kt (called A) for operaton wth dal fel. emssons were calclated sng the proposed methodology, processed by SOFT 1. Table : Emsson ass Flow Rate at W for Desel Pont Power Consmpton (kg/h) NOx (g/h) (g/h) (g/h) kw Desel Ar Balance Standard ethod Balance Standard ethod Balance Standard ethod 1 0,0 0,46 55, ,9 16,49 41, , 11,91 445, ,4 17,0 497, ,0 8,64 38, ,6 1,61 381, ,8 5,14 63, ,9 1,19 51, ,0 7,33 40, ,3 5,01 577, ,6 9,76 53, ,6 0,41 559, ,5 15,04 543, Table 3 : Emsson ass Flow Rate at W for Dal Fel (kt A) Pont Power Consmpton (kg/h) Sbsttton Emsson Flow Rate (g/kwh) kw Desel Ar Gas % NOx 1 0,0 1,70 148,67 1,0 39, ,9 11,70 588,99 13,3 56, 4,94 6,74 11, ,8 13,77 559,36,7 18,1 4,04 8,07 15, ,1 14,65 736,36 11,3 46,6 3,19 1,87 0, , 11,90 386,13 0,9 7,9 5,17 1,03,5 6 86,0 11,54 498,7 8,6 45,7 4,44 6,87 10,78 7 7,7 8,73 334,71 1,0 11,5 5,7 16,78 15, ,6 15,03 796,61 15,8 54,3 3,59 9,80 13, ,3 11,41 478,1 1,0 9,0 4,75 19,68 9, ,0 18,93 95,90 13, 44,1,85 13,58 0, ,0 15,84 67,45 0,8 5,4 3,70 13,16 8, , 5,13 85,58 0,9 3,9 4,14 0,65 1, ,6 17,67 716,66 0,8 4,9 3,85,14,14 5. FLOW EASUREENT FRO EISSIONS Natral and ar mass flow rate can be calclated from emssons measrements. It was shown n [4] that the ar/fel rato can be calclated from composton. Also, the larger the flow rate, the better the accracy. The same methodology can be appled for dal feled engnes. Sometmes, natral mass flow rate measrement s not made drng a test. In order to recover the nformaton, the chemcal reacton mass balance method can be sed. In ths case, a slght modfcaton can be made on the proposed model. Becase of the fact that there s a mssng nformaton abot the flow rate, another hypothss mst be made, so that the system of eqatons can be solved. Performance smlatons have shown that the calclated ar composton by the proposed model s approxmately eqal to the standard one, that s, 1 % O and 79 % N. Therefore, t was decded to ntrodce another eqaton n place of Eq. (1). h = 3,76. g (4) The system of eqatons to be teratvely solved s composed of Eq. (16), (17), (18), (19), (0), () and (4). A software (SOFT ) was developed to perform the calclatons. Its valdaton was made by sng the same data of Table 3, calclatng the natral mass flow rate and comparng to the measred vale. Table 4 presents the reslts. It s shown that low flow rate vales are not estmated correctly by the model. On the other hand, larger vales are estmated to wthn less than 5 %. Emsson mass flow rates are also estmated by SOFT 1 and SOFT, comparng the reslts to the ones obtaned by the methodology proposed n ths paper. The dfferences are less than 5 %, what valdates the model. Table 4 : Flow measrement from emssons : Valdaton. (kt A) Pont Power Consmpton (kg/h) NOx (g/h) (g/h) (g/h) Natral Gas(kg/h) kw Desel Ar easred SOFT SOFT 1 SOFT easred SOFT 1 SOFT easred SOFT 1 SOFT easred 0,0 1,70 148,67 1,0-0, ,9 11,70 588,99 13,3 13, ,8 13,77 559,36,7, ,1 14,65 736,36 11,3 10, , 11,90 386,13 0,9 1, ,0 11,54 498,7 8,6 8, ,7 8,73 334,71 1,0-0, ,6 15,03 796,61 15,8 15, ,3 11,41 478,1 1,0 0, ,0 18,93 95,90 13, 14, ,0 15,84 67,45 0,8-0, , 5,13 85,58 0,9 0, ,6 17,67 716,66 0,8 0, Fnally, another dal fel converson kt (called B) was tested at W, wthot measrng the natral flow rate. Table 5 and 6 presents the reslts, respectvely wthot and wth a catalyst, processed by SOFT. Table 5 : Emsson ass Flow Rate at W for Dal Fel. Wthot catalyst. (Kt B) Pont Power Consmpton (kg/h) Sbsttton Emsson Flow Rate (g/kwh) kw Desel Ar Gas % NOx 1 0,9 1,55 147,3 0,0 0,0 65,43 19,81 6,4 11,4 4,63 331,6 0,0 0,0 1,7 6,74 1,43 3 8,4 4,83 346,8 3,1 4,0 7,06 19,36 38, ,4 4,94 397,0 8,0 64,6 6,78 13,47 5, ,7 9,34 473,7 8,6 51,0 7,63 8,16 11, ,3 17,48 606,0 6,5 9,6 6,79 4,93 6,15 7 1,1 1,56 146,7 0,0 0,0 56,66 0,85 6, ,6 3,51 995, 9,1 30,4 6,41 7,57 9, ,0 14,31 887,7 1,5 49,7 6,09 16,09 3, ,5 8,37 753, 1,8 63,3 5,57 7,91 50, ,9 6,9 616,4 7,8 58,3 6,51 36,73 79, ,5 7,94 545,6 0,0 0,0 13,83 8,3, ,9 1,53 147,6 0,0 0,0 66,03 4,8 8,15

5 Table 5 : Emsson ass Flow Rate at W for Dal Fel. Wth catalyst. (Kt B) U NO x NOx,5 = / = 3,% (7) Pont Power Consmpton (kg/h) Sbsttton Emsson Flow Rate(g/kWh) kw Desel Ar Gas % NOx 1 0,0 1,5 145,8 0,0 0, ,1 4,64 37,8 0,0 0,0 1,09 0,74 0,51 3 8,0 5,19 336,6,5 35,6 7,45,4 9, ,9 5,80 376,5 7,0 57,8 7,46 0,5 19,0 5 83,7 11,13 440, 6,9 41,3 8,0 0,1 5, ,6 19,81 54,1 5,0,1 6,19 0,09 0,98 7 0,0 1,50 146,5 0,0 0, ,5 7,00 833, 6,3 0,8 6,50 0,3, ,8 15,7 76,1 10,8 44,5 7,11 0,56 6, , 9,10 643,1 11, 58,1 6,49 0,88 17, ,8 6,63 557,5 7,3 55,4 8,01 8,3 54, ,1 7,67 516,6 0,4 5,8 13,90 0,86 1, ,0 1,47 146,1 0,0 0, The ncertanty of moleclar mass can be calclated from Eq. (13) : [(. ) ] 1/ = 1 r + s (8) Both r and s depend only the rato c/a, Eq. (15). However, both gás and desel mass flow rate can be measred wth an ncertanty of ± %. Ths ts ncertanty becomes : 6. UNCERTAINTY ANALYSIS Assmng that the composton n the es follows the proposed model, the ncertanty of measrements for the emsson mass flow rates can be made accordng to [5]. Usng Eq. (8) and (9), the followng eqaton can be obtaned for the combned ncertanty of measrement ( m & ) for each emsson mass flow rate, from the standard ncertanty of molar concentraton ( ), moleclar mass ( ( & ) : m ) and mass flow rate x = + desel desel 1/ r. c =. c = 1,4% (9) r 1,113 r = (30) ( ) s 4,09 s = (31) ( ) s. c =. c x = x + + (5) Then [( 1,113 r) ( 4,09 s) ] 1/. = (3) olar concentraton can be measred to wthn ±,5 % wth the HORIBA meter. The mass flow rate can be measred to wthn approxmately %, whch s the ar mass flow rate relatve ncertanty of measrement, the greatest contrbton to t n Eq. (7) Eqvalent moleclar mass relatve ncertantes of measrement for and NO x are assmed to be neglgble, followng what has been establshed by standard [1]. Therefore, sng Eq. (5), emsson mass flow rate ncertanty can be calclated as : U,5 = / = 3,% (6) Table 6 shows that the ncertanty of measrement of moleclar mass s very small. Table 6 : Uncertanty of measrement of mass flow rate Pont r s c/a c/a Uncertanty of easrement m Absolte Relatve Relatve (k=1) % (k=1) % (k=) 1 1,098 3,908 17,089 6, ,0953 0,0048 0,05 3,0 1,105 4,043 17,303 13, ,1843 0,005 0,015 3,0 3 1,078 3,49 16,431, ,0318 0,0081 0,049 3,0 4 1,10 3,973 17,191 8, ,150 0, ,00 3,0 5 1,05,963 15,59 0, ,013 0, ,061 3,0 6 1,101 3,965 17,179 8, ,108 0, ,01 3,0 7 1,064 3,03 15,973 1, ,0186 0, ,059 3,0 8 1,104 4,031 17,83 1, ,1704 0,0070 0,016 3,0 9 1,057 3,048 15,77 1, ,014 0,0095 0,061 3,0 10 1,100 3,950 17,155 7, ,1130 0, ,0 3,0 11 1,041,735 15,3 0, ,008 0, ,058 3,0 1 1,033,559 14,954 0, ,0058 0, ,053 3,0 13 1,039,677 15,140 0, ,0073 0, ,057 3,0

6 Therefore, the ncertanty of measrement of mass flow rate can be calclated as before : U,5 = / = 3,% (33) In conclson, emsson mass flow rate can be measred to wthn ± 3, %, f molar composton s measred to wthn ±,5 %, and mass flow rate to wthn ± %. 7. NCLUSIONS The paper presents the methodology for calclatng the emsson mass flow rate from measred vales of molar concentraton for dal feled desel engnes. Also t shows that and ar mass flow rate can be accrately calclated from measred vales of emssons, by sng a chemcal reacton mass balance. Assmng that the composton n the es follows the proposed model, an ncertanty analyss shows that NO x, and mass flow rates can be measred to wthn ± 3, %, when molar emsson composton are measred to wthn,5 %, and desel, natral and ar are measred to wthn %. REFERENCES [1] ABNT, Veíclos rodováros atomotores Análse e determnação do gás de escapamento segndo cclos ETC, ESC e ELR, Projeto 05: para desel, 005, ABNT. [] EPA, Emsson factor docmentaton for AP-4 Secton 3.4, Large statonary desel and all statonary dal fel engnes, EPA contract No. 68-D0-010, [3] KUSAKA, J.,OKAOTO, T., DAISHO, Y., KIHARA, R. & SAITO, T., Combston and emsson characterstcs of a desel engne dal-feled wth natral gás JSAE Revew 1, 000, [4] Do Val, L.G., Análse crítca do desempenho de plantas de cogeração, Sc Thess, PUC-Ro, 001. [5] ISO GU, Gde to the Expresson of Uncertanty of easrement, ISO, 1995.