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Renewable Energy 30 (2005) 413–420

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Technical note

Pyrolytic oil from fixed bed pyrolysisof municipal solid waste and its

characterization

Mohammad Nurul Islam, Mohammad Nurul Islam �,Mohammad Rafiqul Alam Beg, Mohammad Rofiqul Islam

Department of Mechanical Engineering, Rajshahi University of Engineering

and Technology Rajshahi 6204, Bangladesh

Received 30 November 2003; accepted 2 May 2004

Abstract

Municipal solid waste, in the form of paper waste, has been converted into liquid oil by afixed bed pyrolysis process. Favorable properties for pyrolysis conversion such as high vol-atile content, elemental composition, and thermochemical behavior of the waste were inves-tigated by characterization study. The waste paper feedstock was pyrolyzed in an externallyheated 7 cm diameter, 38 cm high fixed bed reactor with nitrogen as a carrier gas. The pyrol-ysis oil was collected in a series of condenser and ice-cooled collectors. The char was separ-ately collected while the gas was flared. The effect of process conditions, like fixed bedreactor temperature, feedstock size and effect of running time on the product yields, wasstudied. The composition of the oil was determined at a bed temperature of 450

vC, at

which the liquid yield was maximum. The liquid product was analyzed for physical, elemen-tal and chemical composition using Fourier transform infra-red (FTIR) spectroscopy.# 2004 Elsevier Ltd. All rights reserved.

1. Introduction

Liquid from municipal solid waste through thermochemical conversion processis expected to play an important role in energy future as high value energy carriers[1]. Recently, apart from conventional bio-fuel production through biologicalroutes, liquid fuel recovery from solid waste has been getting increasing attention[2]. To meet the demands of the increasing population in Bangladesh, the

M. Nurul Islam et al. / Renewable Energy 30 (2005) 413–420414

production of paper is increasing day by day. In the years 1996–1997, 1997–1998and 1998–1999, the production of paper in Bangladesh was 59,862, 67,515 and85,801 metric ton, respectively [3]. After use this creates waste disposal problem.This carbonaceous solid waste is a renewable source and, therefore, the potential ofconverting it into a useful energy such as liquid fuel should be considered. In thisway, this waste would be more readily usable and environmentally acceptable. Thepyrolysis liquid may be used directly as a fuel by its catalytic upgrading or whenadded to petroleum refinery production [4,5]. Solid char may be used to produceactivated carbon. Besides the char has a potential of being used as a fuel. The gashas its potential use as a fuel. After obtaining the liquid oil by the pyrolysis pro-cess, this was checked for its physical and chemical properties, and compared topetroleum fuels.

2. Material and method

2.1. Solid waste

Waste paper was collected locally at Rajshahi, Bangladesh. The proximate andultimate analyses of the solid waste paper is presented in Table 1. For investi-gation, three different feedstock of sizes 0–1 cm, 1–2 cm and the usual (as received)form were used. The feedstock was oven dried for 24 h at 110

vC prior to pyrol-

ysis.

2.2. Experimental

Waste paper feedstock was pyrolyzed in an externally heated stainless steel fixedbed reactor system. The main components of the system are fixed bed reactor, gaspreheating chamber, reactor feeder, liquid condenser, and ice-cooled liquid collec-tors. The effective length of the reactor is 340 mm, and the diameter is 76 mm. Theschematic diagram of the fixed bed pyrolysis system is shown in Fig. 1. A cylindri-cal biomass source heater was used to heat the reactor and the gas-preheatingchamber. The temperature of the reactor was controlled by varying the supply ofair by means of an air blower. Nitrogen gas was supplied in order to maintain theinert atmosphere in the reactor, and to dispose of the pyrolyzed vapor products to

Table 1

Proximate and ultimate analyses of waste paper

Proximate analysis

Wt% Elemental analysis A sh free basis

(wt%)

Moisture content

6.51 Carbon (C) 3 9.71

Volatile matter

76.31 Hydrogen (H) 7.14

Fixed carbon

11.15 Nitrogen (N) –

Ash content

6.03 Oxygen (O) 5 3.15

Sulfur (S) –

415M. Nurul Islam et al. / Renewable Energy 30 (2005) 413–420

the condenser. Pyrolysis vapor condensed into liquid in the condenser and was

collected in the liquid collectors. The non-condensed gas was flared to the

atmosphere.

Fig. 1. Schematic diagram of fixed bed pyrolysis system.

M. Nurul Islam et al. / Renewable Energy 30 (2005) 413–420416

3. Results and discussion

3.1. Feedstock characteristics

Characterization studies are important for suitability of the feedstock for ther-mochemical conversion. High volatile matter content with low ash and sulfur con-tent is the main criterion for pyrolysis conversion [5]. From Table 2, it appears thatthe high volatile content of waste paper favors the pyrolysis conversion.

3.2. Product yield

The products obtained from the pyrolysis of waste paper are liquid oil, solidchar, and gas. At an operating temperature of 450

vC with the usual form of feed-

stock, liquid production is found to be maximum.

3.3. Effects of operating temperature

The relationship between the variation of percentage of mass liquid, char andgaseous products with that of mass of feed at different reactor bed temperatures ispresented in Fig. 2. The results show that as the operating temperature wasincreased, the liquid yield was increased up to 450

vC at a product yield of 54 wt%.

After this temperature, the liquid yield decreased. At a lower temperature of 300vC,

the liquid product was found to be 40 wt% of the dry feedstock only. At a highertemperature of 500

vC, the liquid product was lesser and was found to be about

41 wt% of the dry feed. When the reactor bed temperature was decreased, the liquidproduct was decreased. Also when the temperature was increased, the liquid pro-duct was decreased. The reason for the lower liquid yield at lower temperature maybe due to the fact that the temperature rise was not enough for complete pyrolysisto take place, thus yielding less liquid product. On the other hand, at a higher tem-perature, there was a possibility of secondary decomposition reaction taking place.

3.4. Effect of feed particle size

Fig. 3 represents the percentage mass of liquid, char and gaseous products inrelation to that of feed for different feedstock size at different temperatures. From

Table 2

The FTIR functional groups and the indicated compounds of the waste paper pyrolysis oil

Frequency range (cm�1)

Group C lass of compound

3650–3100

O–H stretching P olymeric O–H, water impurities

3000–2800

C–H stretching A lkanes

2200–1950

CDDC stretching A lkynes

1761–1676

CBO stretching K etones, aldehydes, carboxylic acids

1670–1550

CBC stretching A lkenes

1400–1300

C–H bending A lkanes

1020–950

C–O stretching

O–H bending

P

p

rimary, secondary and tertiary alcohols,

henol, esters, ethers

417M. Nurul Islam et al. / Renewable Energy 30 (2005) 413–420

the result, it is observed that the percentage mass of liquid product was amaximum of 54 wt% for the feedstock of usual size. The feedstock size of 0–1 cmand 1–2 cm produced a maximum percentage of mass of liquid of 45 wt% and52 wt%, respectively. This may be due to the fact that the smaller size particleswere either overheated, or too quickly blown away from the reactor before com-mencing pyrolysis completely.

3.5. Effect of running time

Fig. 4 represents the effect of running time on liquid yield of the pyrolysisof waste paper. It appears that the pyrolysis of waste paper was completed after

of operating temperature on product yields for particle size of usual form (

Fig. 2. Effect as received).

. Effect of feedstock size on the liquid yield for different operating tempera

Fig. 3 ture.

M. Nurul Islam et al. / Renewable Energy 30 (2005) 413–420418

40 min of the experimental run. After this, there was no change in the liquid yielddue to complete devolatilization of the feedstock.

3.6. Analysis of pyrolysis oil

3.6.1. Physical property and elemental analysisThe liquid is found to be highly oxygenated where the oxygen content is 52.91%

as compared to 53.15% for the raw feedstock. The energy content in terms ofhigher heating value of the oil is low, 13.1 MJ/kg, due to the presence of highpercentage of moisture and oxygenated components. The density of the oil is1205 kg/m3 which is also quite high. The liquid can be easily poured at the roomtemperature, and the viscosity is 2.00 cSt at 35

vC, with a low pour point of

�10 vC. The flash point is high. Thus, this can be stored safely at room tempera-

ture. The ash content is 0.35%. The liquid has a low pH value of 1.5.

3.6.2. Compositional analysisThe functional groups of the oil were determined by the absorption frequency

spectra. The possible compositional groups are presented in Table 3. The presenceof water impurities and other polymeric O–H in the liquid is indicated by thebroad absorbance peaks of O–H stretching vibration between 3650 and 3100 cm�1.The alkane group is indicated by the absorbance peak of C–H vibrations between3000 and 2850 cm�1 and C–H bending between 1400 and 1300 cm�1. The absor-bance peaks between 1761 and 1676 cm�1 represented the CBO stretching vibrationindicating the presence of ketones and aldehydes. The frequency range of1670–1550 cm�1 presents alkenes of CBC stretching. The peaks between 1020 and950 cm�1 are indication of the presence of primary, secondary and tertiary alco-hols, phenols, ethers and esters due to C–O stretching and O–H deformation vibra-tions of these functional groups.

Fig. 4. Effect of running time on liquid yield for pyrolysis of waste paper.

419M. Nurul Islam et al. / Renewable Energy 30 (2005) 413–420

3.7. Comparison with biomass derived oil and diesel fuel

Table 3 shows the characteristics of the pyrolysis oil derived from waste paper incomparison with other biomass derived oils and diesel fuel. The elemental analysisshows that carbon and hydrogen contents of the waste paper derived oil are closeto those of the biomass derived oil. The flash point of the oil is higher than that ofdiesel fuel. The density of the oil is higher than that of diesel fuel.

4. Conclusion

Pyrolysis, the thermochemical conversion, successfully converted waste paperinto liquid, char and gas. The elemental composition of the pyrolytic oil is foundto be better than that of the feedstock. The oil was acidic in nature. The heatingvalue of the oil is found to be similar to that of other biomass derived oils. FTIRanalysis shows that the liquid oil contains oxygenated species. The oil may furtherbe upgraded for better fuel properties.

Acknowledgements

The authors are indebted to the Ministry of Science and Technology of theGovernment of People’s Republic of Bangladesh and to Rajshahi University ofEngineering and Technology (RUET), for providing the financial support andnecessary facilities for the study. Thanks are due to the Institute of Fuel Researchand Development, the Analytical Research Division of Bangladesh Council

Table 3

Comparison of waste paper pyrolysis oil with biomass derived pyrolysis oil and fast diesel

Analyses

Waste

paper oil

Sugarcane

bagasse oil [6]

Jute-stick

oil [6]

D

iesel [7] H eavy fuel

oil [8]

Elemental (wt%)

C

40.80 46.27 47.18 8 6.58� 8 5–86

H

6.29 6.55 8.36 1 3.29 1 1–11.5

N

0.0 0.0 – 6 5 ppm 0 .3–0.5

S

– >0.1 – 0 .11 1 .0–2.6

Ash

0.35 0.24 0.33 0 .0 0 .1

O

52.91 46.94 44.13 0 .01 –

Viscosity at

35vC (cSt)

2.00

89.34 12.08 2 .61� 2 00#

Density (kg/m3)

1205 1198.10 1224.70 8 27.1� 9 80�

pH value

1.5 2.75 2.92 – –

Flash point (vC)

200 105 >70 5 3 9 0–180

Pour point (vC)

�8 �24 �14 – 2 5–30

Higher heating

value (MJ/kg)

13.10

20.072 21.091 4 5.18 4 2–43

# @ 50vC; � @ 20

vC.

M. Nurul Islam et al. / Renewable Energy 30 (2005) 413–420420

of Science and Industrial Research (BCSIR), Dhaka, and the Department ofChemistry of Rajshahi University for providing necessary facilities for proximate,elemental, FTIR and other analyses.

References

[1] Horne PA, Williams PT. Petroleum quality fuels and chemicals from the fluidized bed pyrolysis of

biomass with zeolite catalyst upgrading. Renewable Energy 1994;5(2):810–2.

[2] Bangladesh Bureau of Statistics. Statistical Yearbook of Bangladesh. Dhaka: Statistical Division of

Ministry of Planning, GOB; 2001.

[3] Sinha AHM. Enayetullah. Recycling potentials of organic wastes in Dhaka. Earth 1995;5.

[4] Hayes RD. Biomass pyrolysis technology and products. In: Energy, mines, and resources. Renew-

able Energy Branch, Ottawa, Canada, 1988.

[5] Bridgwater AV, Bridge SA. A review of biomass pyrolysis and pyrolysis technologies. In: Bridgwater

AV, Grassi G, editors. Biomass pyrolysis liquids upgrading and utilization. London: Elsevier

Science; 1991, p. 11–92.

[6] Islam MR, Nabi MN, Islam MN. Characterization of biomass solid wastes for liquid fuel pro-

duction. Proceedings of the 4th International Conference on Mechanical Engineering ICME 2001.

Dhaka, Bangladesh, December 26–28. 2001, p. 77–82.

[7] Andrews RG, Patniak PC. Feasibility of utilizing a biomass derived fuel for industrial gas turbine

application. In: Bridgwater AV, Hogon EN, editors. Bio-oil production and utilization. Berkshire:

CPL press; 1997, p. 236–45.

[8] Rick F, Vix U. Product standards for pyrolysis products for use as fuel in industrial firing plants. In:

Bridgwater AV, Grassi G, editors. Biomass pyrolysis liquids upgrading and utilization. London:

Elsevier Science; 1991, p. 177–218.