Katayama, Yukio

Minato, Kazuya

Nakagawa, Tetsuo

Kyoto University Research Information Repository

TitleSelective Pyrolysis of Japanese Ceder to C₁-ChemistryMaterials. I. Particle Size, Part of Wood, Temperature andTime Dependence of Weight Loss and of Conversion Ratio toCOAuthor(s)Nakagawa, Tetsuo; Minato, Kazuya; Katayama, YukioCitationBulletin of the Institute for Chemical Research, KyotoUniversity (1994), 72(3-4): 336-344Issue Date1994-11-30URL http://hdl.handle.net/2433/77583RightType Departmental Bulletin PaperTextversionpublisherKyoto UniversityBull. Inst. Chem. Res., Kyoto Univ., Vol. 72, No. 3-4, 1994    Selective Pyrolysis of Japanese Ceder to  C1-Chemistry          Materials. I. Particle Size, Part of Wood,        Temperature and Time Dependence of Weight            Loss and of Conversion Ratio to CO                         Tetsuo NAKAGAWA*, Kazuya MINATO**                             and Yukio KATAYAMA**                               Received July14,1994    In order to obtain the basic information about he method of utilizing wood for raw materials of C1-chemistry, the valid condition ofpyrolysis of Japanese ceder (Cryptomeria japonica D.Don) powder has been investigated varying particle size, part of wood (i.e. difference between sapwood and heartwood), pyrolysis time and temperature inviews of the weight loss and the conversion ratio to CO. This decomposition reaction has been carried out using pyrolyzer quipped with gas chromatograph. The quantities of the products such as CO, CO2, and CH4 have been measured from the respective peak areas of pyrogram spectra. The negative peak of H2 has also been found in higher temperature gion. In general, the higher pyrolysis temperature is,the more significant the weight loss of wood and the conversion ratio to CO are, which are almost irrespective of both particle size and part of wood.    Key Words : C1-chemistry/ Pyrolysis/ Gas chromatograph/ Weight loss/ Sapwood/ Heartwood/ Conversion ratio                           1. INTRODUCTIONC1-chemistry is one of the most effective tools of producing chemically various useful compounds uch as methanol1"3) from mainly carbon monoxide (CO) and hydrogen (H2).41 However, there remains still a significant problem what is used for the raw materials. The materials must be both abundant and C-rich. Wood is mainly composed of C (50wt%), H (6wt%), and 0 (44wt%),5l and it is said that the main gaseous products of pyrolyzing wood are H2, CO, methane (CH4), and carbon dioxide (CO2),6l and therefore wood is worth noticing from the viewpoint of C1-chemistry. In particular, if the commercially valueless wood is used for the materials, that is significant for considering the conservation of limited natural resources.    By the way, pyrolysis gas chromatography (PY-GC) has been used for the analyses of various polymer compounds, but this tool has not been much applied to wood science extensively.7'81 Many studies on wood pyrolysis are mainly on the change of weight loss.9-11l Hence it is interesting to try to use this PY-GC procedure for wood decomposition analysis.    In this paper, in order to obtain the basic information about themethod of utilizing wood for  * : Laboratory ofInterface Science I, Institute for Chemical Research, Kyoto University, Uji,    Kyoto-fu, 611. ** t QL, ki'111+f : Department ofWood Science and Technology, Faculty of Agriculture, Kyoto    University, Sakyo-ku, Kyoto, 606-01. ( 336 )                                     Pyrolysis of Japanese Ceder        raw materials of  C1-chemistry, we have investigated the dependence of the pyrolysis, of Japanese       ceder (Cryptomeria japonica D. Don) powder on particle size, part of wood (sapwood or heartwood),        reaction temperature, and time using gravimetric and the PY-GC procedure, and have searched       for the more useful condition of high yield of CO.                                  2. EXPERIMENTAL        2.1. Sample           The powder (60-80, 80-100, and 100-120 mesh) of sapwood and heartwood of Japanese        ceder (Cryptomeria japonica D. Don) was used without further pre-treatment. No catalyses were         used.       2.2. Pyrolysis           The pyrolyses have been carried out using a Simadzu pyrolyzer PYR-IA equipped with a        Simadzu gas chromatograph GC-7AG. The experimental geometry is shown as Fig. 1. The        helium (He) gas was used as a carrier of decomposed compounds.     GasHe gas        chromato -b omb                   graph —~ A—~                  C D 111.11111111m1MIE_ — E F F—                                         T H                 Fig. 1. Experimental geometry for pyrolysis gas chromatography (PY-GC).           The about 10-mg sample was weighted correctly with the platinum (Pt) plate, taken in the       tube (H) with the bar (G) in front of the heater (I). The gas route was switched from B•E--•        C—+A to B—•D-04.^A, and the tube was completely filled with the carrier gas, and the sample       was taken to the heater and heated there. The pyrolyses were conducted from 200 to 700°C, and        from 0.5 to 40 minutes.        2.3. Gas chromatography           The identification of produced gaseous compounds was carried out by the use of a Simadzu       gas chromatograph GC-7AG equipped with a thermal conductivity detector (TCD). At first,       we tried to use the nitrogen (N2) gas as a atmosphere of pyrolyses and a carrier, but the spectra of       CO and CO2 were splitted. This is why the concentration dependence of thermal conductivities       for the N2-CO and N2-CO2 systems is changed complicatedly.121Hence instead of the N2 gas,        we used the He gas. For the H2-He system, the same phenomena appeared as for the N2-CO        and N2-CO2 ones, and therefore we gave up the quantitative analysis of the H2 gas. Active        carbon (60-80 mesh) was used for the column packing reagent. The temperature of the        column was 70°C. The speed of the He carrier gas was 50 ml/min. The retention times of        standard gases are shown in Table 1. There is a linear relationship between the volume and the ( 337 )                         T. NAKAGAWA, K. MINATO and Y. KATAYAMA   Table 1. Retention times of stadard gases. Table 2. Regression equations for calibrating                                                           the volumes of stanard gases.    Stadard gas Retention  time/min.                                               Standard gasCalibration curve   H20.8    Air1.7AirV=1.27 X 10 4A-0.0045    CO2.0COV=1.11 X 10 4A-0.0070    CH43.6CH4V=1.25 X 10 4A-0.0274    CO28.5CO2V=9.71 X 10 5A-0.0184 peak areas of pyrogram for the whole standard gases, and the first order regression equations for calibrating the volumes of the respective gases can be obtained (see Table 2).                      3. RESULTS AND DISCUSSION 3.1. Weight loss Temperature dependence     Figure 2 shows the relationship between pyrolysis temperature and weight loss of Japanese ceder powder for 10 minutes. Where W is the initial weight of wood, and W is the final one. For both sapwood and heartwood, the weight loss occurs significantly in the 200--300°C range, irrespective of the particle size and part of wood. These findings indicate that these decomposition reaction occurs effectively more than 300°C temperature range. We also try to perform the pyrolyses for 5 or 20 minutes, and obtain the similar results to that for 10 minutes. Time dependence     Figure 3 shows the relationship between pyrolysis time and weight loss of Japanese ceder 1.0 ------------------------------------------------------------------------1.0 -----------------------------------------------------------------------                  0.8 -I(B)        (A 0.8e)°-              °    0.6 —   00.6 —       -                   o 33 0.4—0.4—      SNg0.2—6\~~B 0.2—eo ° I I I I I ItI I I I I I I     0 100 200 300 400 500 600 7D0 0 100 200 300 400 500 600 700 TI°CT I ° C   Fig. 2. Relationship between pyrolysis temperature (T) and weight loss of Japanese ceder powder (W/W). (A) and (B) represent sapwood and heartwood, respectively. Pyrolysis period is 10          minutes. 0, A, and ^ are for 60-80, 80-100, and 100-150 mesh, respectively. (338)                              Pyrolysis of Japanese Ceder 1.0 ---------------------------------------------------------------------------1.0--------------------------------------------------------------------  0.8  — (A)0.8- (B) ° 0.60.6 r 33e ° 3 03 0.4 v0.4  oO,O8     ° ° 0.2—00.2—    i iii i t i i  010 2030 40 0 10. 20 30 40 t/mint/min     Fig. 3. Relationship between pyrolysis time (t) and weight loss of Japanese ceder powder (W/W).             Pyrolysis temperature is 300°C. Legends are the same as in Fig. 2.  powder at 300°C. Seeing this figure, we find that it is necessary to decompose these samples  enough for more than 10 minutes at 300°C. We also try to perform the pyrolyses for 200, 400,  and 500°C. For 200°C, the curve of weight loss decreases slowly with reaction time. For 400°C  and 500°C, we know that it is necessary to decompose enough for more than 5 minutes and 1  minute, respectively.  3.2. Conversion to CO Pyrogram (Gas chromatogram)      Figure 4 shows the temperature dependence of pyrogram (gas chromatogram) of the  pyrolysis gaseous C i-products of Japanese ceder powder (sapwood, 60-80 mesh). We can  easily recognize that the areas of respective Ci-compound peaks are increasing as the reaction  temperature rises. For the H2 gas, we cannot discuss quantitatively because of the above- mentioned reason. However, we can admit the negative peak due to this H2 gas at 700°C.  These facts suggest qualitatively that the amount of the raw materials of C1-chemistry such as H2  and CO are more increasing as the reaction temperature raises.  Temperature dependence      In order to discuss the results obtained quantitatively, we evaluate the conversion ratio to  CO using the following functions : X= 10010/(1) Y=100ze,/(W,—W)(2)  where W is the initial weight, W is the final one, w is the weight of every produced gas (CO,  CO2, and CH4). The function X indicates the conversion ratio to CO in the initial wood, and Y  does that in the decomposed products. We postulate that all the decomposition products are (339)                        T. NAKAGAWA, K. MINATO and Y. KATAYAMA                   C                       D     (1) B i700°C    CE          B ~                                           300°C        BBnnC E                                             200°C                Retention Time            Fig. 4. Temperature dependence of gas chromatogram of the pyrolysis gaseous                   products of Japanese ceder powder. A, B, C, D, and E are for H2, air,                   CO, CH4, and CO2, respectively. ideal gases and residuals, and we estimate the w values using the following equation : w=PVM/RT(3) where P is the pressure (P= 1 atm), V is the volume, M is the molar mass, R is the gas constant, and T is the absolute temperature (T= 20°C). We use the V values in Table 2, and convert V to w using Eq. (3).    Figures 5 and 6 are the relationship between pyrolysis temperature and the conversion ratio to CO, and the weight ratio of CO to the pyrolysis products, respectively. Below 300°C region, both X and Y functions of heartwood are larger than those of sapwood irrespective of particle size. Above this temperature, however, vice versa. Both X and Y increase tremendously as the pyrolysis temperature is higher, and moreover the rate of increasing of these function on temperature also increase. We can safely say that the high yield of CO is obtained as the reaction temperature is higher.    Figures 7 and 8 are the same meaning as Figs. 5 and 6 for CO2, and Figs. 9 and 10 are for CH4. For the CO2 gas, both X and Y increase more as the temperature is higher, irrespective of particle size and part of wood, but the rate of increasing of these functions decrease. For the CH4 gas, however, that of these function increase. This fact suggest that the generated H radicals (340)                             Pyrolysis of Japanese Ceder act violently as reduced regents for CO or CO2 in the higher temperature range. We must consider the useful condition of the conversion of wood to CO with the CO2  and CH4 gases decreasing because both gases are chemically inert and invalid for the raw materials of 50 --------------------------------------------------50---------------------------------       II40—40—                                0                                                                                ^   00 <:1A`30(9200        o/                                    ^/     10— /10— S    1-9 I - I I I II 1 1 I ^ I I     0 100 200 300 400 500 600 700 0 100 200 300 400 500 600 700 TI°CTI°C    Fig. 5 Relationship between pyrolysis temperature (7) and conversion ratio of Japanese ceder          powder to CO (X). Pyrolysis period is 10 minutes. Legends are the same as in Fig. 2. 50 —50------------------------------------- ^/ 40 — 740 —^ 0                                                                           A                    /30— (A) ^30—(B)                         /9 20 —20 —            /2A                                               / o 10-^10—    ~/22'§'    Ii- 11 I I 11 1 I 1 1 1 1     0 100 200 300 400 500 600 700 0 100 200 300 400 500 600 700 T/°CT/°C    Fig. 6. Relationship between pyrolysis temperature (7) and weight ratio of CO to the pyrolysis           products (Y). Pyrolysis period is 10 minutes. Legends are the same as in Fig. 2. (341)                                     T.  NAKAGAWA, K. MINATO and Y. KATAYAMA 30—30—      20- (A)8 'g_ 20—(B)                                  ~—         _       (A)°i°(Bl.~ee   k/p NcQ4 10—/°10—°                                       °/     ^^O/0           I •~p}t7Y/1I I I I~~                           I I I I I I I               0 100 200 300 400 500 600 700 0 100 200 300 400 500 600 700 T 1°Crl°C                 Fig. 7. Relationship between pyrolysis temperature (T) and conversion ratio of Japanese ceder                        powder to CO2 (X). Pyrolysis period is 10 minutes. Legends are the same as in Fig. 2. 3030 —               D7(B) —(, `) °a/°20—)/ho                                                H0                                   ° 10-/$/O108~° I I I I I I I I 1 I 1 1 I I  0 100 200 300 400 500 600 700 0 100 200 300 400 500 600 700 TI°CTI°C                Fig. 8. Relationship between pyrolysis temperature (T) and weight ratio of CO2 to the pyrolysis                        products (Y). Pyrolysis period is 10 minutes. Legends are the same as in Fig. 2. 20—20—      (A)e(B) k10-H>c10—a/    °a       8~~6/         0,.---0,~ o_ck—"0~°o_—48'a 1 1 I 1 I 1 I I1 1 I I I I I I  0 100 200 300 400 500 600 700 0 100 200 300 400 500 600 700 TI°CTI°C                 Fig. 9. Relationship between pyrolysis temperature (T) and conversion ratio of Japanese ceder                       powder to CH4 (X). Pyrolysis period is 10 minutes. Legends are the same as in Fig. 2. (342)                             Pyrolysis of Japanese Ceder  20  -20 - n, 10-(A)o                                         0.--           / 10-(B)Q/                  od 1 1 l 1 1 1 1 1 i 1 1 1 1 1 1 l     0 100 200 300 400 500 600 700 0 100 200 300 400 500 600 700 T I °cT I °c    Fig. 10. Relationship between pyrolysis temperature (7) and weight ratio of CH4 to the pyrolysis            products (Y). Pyrolysis period is 10 minutes. Legends are the same as in Fig. 2. Table 3. Relationship between pyrolysis Table 4. Relationship between pyrolysis time          time and conversion to CO forand conversion to CO for sapwood at      sapwood at 300°C.700°C.    t/min 1 5 10 20t/min 1 5 10 20 xl% 60- 80 mesh 3.3 4.3 2.8 5.9 x/% 60- 80 mesh 34.2 - 37.2 33.8 100-150 mesh 3.3 3.9 3.8 5.2100-150 mesh 40.3 40.0 40.5 42.2 y/% 60-- 80 mesh 5.5 6.4 3.8 7.7 yl % 60- 80 mesh 38.4 - 44.7 38.7 100-150 mesh 5.2 5.2 5.5 7.3100--150 mesh 47.7 41.7 42.9 47.8 CI-chemistry.    Summarized the above-mentioned findings, we conclude that the higher temperature is necessary for occurring the effective pyrolysis. Time dependence    Tables 3 and 4 show the relationship between pyrolysis time and conversion to CO at 300°C and 700°C, respectively. Obviously, we can hardly admit the the time dependence of conversion to CO, and about 10 minutes are sufficient for obtaining high yield of CO.                       4. CONCLUDING REMARKS    The valid condition of pyrolysis of Japanese ceder powder has been investigated varying particle size, part of wood (i.e. difference between sapwood and heartwood), pyrolysis time, and temperature in views of the weight loss and the conversion ratio to CO. The higher pyrolysis temperature is, the more significant the weight loss of wood and the conversion ratio to CO are, which are almost irrespective of both particle size and part of wood. In the lower temperature region (e.g. 200°C), the longer pyrolysis period is more effective, but the higher one, there is hardly the period dependence of weight loss and conversion ratio to CO. The dependence of the portion of CO in produced gases on temperature and time, and the kinetics for this system will be discussed in Part II.                        ACKNOWLEDGMENT     We thank Professor Soichi Hayashi, Dr. Junzo Umemura, and Dr. Noriyuki Kimura, (343)                        T. NAKAGAWA, K. MINATO and Y. KATAYAMA Institute for Chemical Research, Kyoto University, for giving  encouraged  to us and for giving their valuable suggestions and discussion to us.                             REFERENCES(1) R.G. Herman, K. Klier, G.W. Simmons, B.P. Finn, J.B. Vulko, T.P. Lobylinski, J. Catal., 56, 407    (1979). (2) R.M. Agny and C.G. Takoudis, Ind. Eng. Chem. Prod. Res. Des., 24, 50 (1985). (3) P. Villa. P. Forzatti, G. Buzzi-Feraris, G. Garone and I. Pasquon, Ind. Eng. Chem. Process Des. Des., 24,    12 (1985). (4) See for example, S. Tanaka, Kagaku Sohsetsu, 36, 51 (1982) ; E. Kikuchi, "Yukishigen no Kagaku",    Kagaku Zoukan, No.90, Kagaku Dojin, Kyoto, p.65 (1981). (5 ) J. Nakano, "Mokuzai Kagaku", Yuni Syuppan, Tokyo, p. 5 (1983). (6) G. Simmons and M. Sanchez, J. Anal. Appi. Pyrolysis, 3, 161 (1981). (7) K. Kuroda, Mokuzai Kogyo, 48, 460 (1993). (8) T.P. Wampler, J. Anal. Appl. Pyrolysis, 16, 291 (1989). (9) D.F. Arseneau, Can. J. Chem., 39, 1915 (1961). (10) R.M. Knudsen and R.B. Williamson, Wood Sci. Technol., 5, 176 (1971). (11) H.A. Becher, A.M. Phillips, and J. Keller, Combust. Flame, 58, 163 (1984). (12) L.S. Schmauch and R.A. Dinerstein, Anal. Chem., 32, 343 (1960). ( 344 )

Selective Pyrolysis of Japanese Ceder to C₁-Chemistry Materials. I. Particle Size, Part of Wood, Temperature and Time Dependence of Weight Loss and of Conversion Ratio to CO

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Selective Pyrolysis of Japanese Ceder to C₁-Chemistry Materials. I. Particle Size, Part of Wood, Temperature and Time Dependence of Weight Loss and of Conversion Ratio to CO

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