Combustion Characteristics of High density Briquette produced from Sawdust Admixture and Performance in Briquette Stove

London Journal of Research in Science: Natural and Formal
Volume | Issue | Compilation
Authored by Bello, RS , NA
Classification: NA
Keywords: Briquette, high density, extruder, burn rate, normalized, ignition, thermal, efficiency, consumption.
Language: English

Combustion characteristics of high density briquettes produced from sawdust admixture at three moisture contents of 12%, 10% and 8% using screw press extruder were investigated in this work. The briquettes were burnt in free air and developed  riquette stove and the combustion characteristics data collected and analysed. The burn characteristics investigated include ignition time, burn time, mass reduction, normalized burn rate, the effects of density on briquette characteristics and stove performance. The results indicated that briquettes’ self-ignition time in open air and stove was slow  however burns with steady flame, when burning is established. The high density of the briquette was responsible for slow flame propagation resulting in longer time to burn out while lower density briquettes reaches burning phase faster than higher density briquettes. The normalized burn rate increases with increase in briquette density. The stove performance characteristics are largely dependent on fuel material quality. The stove thermal efficiency increases with increase in briquette material moisture content while the specific fuel consumption increases with decrease in moisture content. From this results, there is an inverse relationship between specific fuel combustion and thermal efficiency of the stove. The higher the briquettes particle moisture, the higher the specific fuel combustion and the lower the stove thermal efficiency and vice versa.

               

Combustion Characteristics of High-Density Briquettes Produced from Sawdust Admixture and its Performance in Briquette Stove

Bello R. S. α & Onilude  M. A. σ

____________________________________________

ABSTRACT

Combustion characteristics of high-density briquettes produced from a screw press extruder using sawdust admixture at  three particle moistures of 12%, 10%, and 8% was investigated in this article. The briquettes produced were burnt in free air and briquette stove while the combustion data collected was analyzed. The combustion characteristics investigated include ignition time, total burning time, mass reduction, and burn rates. The effects of particle moistures and briquette density on stove performance were also evaluated. The results show that self-ignition time and flame propagation for each briquette in open air and the stove was slow. Briquetes from lower particle moisture reach the burning phase faster than higher particle moisture briquettes. The normalized burn rate for all briquettes increased with an increase in density. The specific  fuel consumption increases with decrease in particle moisture. At higher particle moisture, the specific fuel combustion reduces and vice versa for all briquettes. This result is indicative of  an inverse relationship between specific fuel combustion and stove thermal efficiency.

Keywords: Briquette, high-density, extruder, burn rate, normalized, thermal efficiency.

Author α: Department of Agricultural & Bioenvironmental Engineering Technology, Federal College of Agriculture Ishiagu, Nigeria

σ: Department of Wood Products Engineering, University of Ibadan, Nigeria

  1. INTRODUCTION

Among the several energy resources available, fossil fuel remained the most exploited resource in today’s technological world. Economic growth, urbanization, population increase, and global energy needs have led to overdependence and increased demands on the use of fossil fuels, which consequently had contributed to the outrageous increases in fuel prices in developing countries of Africa and Asia, especially in Nigeria. This increasing trend of fossil fuel prices coupled with worsening effects of global warming have prompted the exploration of alternative sources of energy such as wood and briquettes (Lim, 2007). However, these resource-based materials are under pressure from both human activities and natural factors, including draught.

According to a 2010 report of the Energy Commission of Nigeria, Nigeria, as of 2010, was consuming about 43.4 x 109 kg of fuel-wood annually (Ajiboye et al., 2016) with an average daily consumption of about 0.5 to 1.0 kg of dry fuel-wood per person (Olorunnisola, 2007). This invariably made the demand for fuel wood to have risen to about 213.4x103 metric tons, while the supply would have decreased to about 28.4x103 metric tons by the year 2030 (Adegbulugbe, 1994). The complete reliance on the use of wood, which, is on the increase on daily basis especially in the less technologically developed  countries of the world as stated by Aremu and Agarry (2013), for industrial and domestic cooking would not solve the present energy crisis; rather it would lead to deforestation or desertification resulting  in  further scarcity of this resource (Salunkhe, et al, 2012). As noted by Olorunnisola, (2007), this should, of necessity be characterized by a departure from the present subsistence energy usage levels, to more sustainable and diversified energy options such as densification into briquettes.

Different raw material properties produce different conditions during the densification process, and this causes differences in the final quality of the products (Qian et al., 2013, Križan et al., 2015). It is necessary, therefore, to characterize these material properties to know out their optimal factor for densification. It is equally important to determine the impact of the technological and material variables: raw material parameters; technological process; and structural variables (Križan et al., 2015), known to grossly affect the final quality of the briquettes.

Variability in biomass materials and structural requirements have made applicable technological processes and machines used in high-density briquette production defer. The utilization of high-pressure technologies in the densification of loose materials and their use in boiler furnace chambers for remote industrial and domestic heating are strong reasons to study their combustion characteristics and increased applications (Risović et al., 2008).

Chin and Siddiqui, 2000 and Faizal et al, (2011) gave a good review of research works on the combustion characteristics of biomass. Husain et al, (2002) documented the combustion characteristics of low-density briquettes containing fiber and shell residues in 60:40 ratio  using 10% starch (of the weight of residues)  as binding agent. Li (2003) investigated the ignition temperature of coal briquette with plastic (polyethylene) addition and found that the ignition temperature decreased from 413 to 373°C when plastic was added. Currently, there are relatively few published works on the combustion characteristics of high-density briquettes produced from sawdust admixtures and its effect on different property behaviours compared to its low and medium-density briquettes. In producing high quality briquettes, several combustion characteristics such as burning rate, fuel consumption rate, smoke generation, flame propagation, ignition time, gross calorific values, and heat release values among others are required.

However, the majority of these studies were extensively carried out and reported for low and medium-density (using manual or piston press technologies). However, the present level of literature and data are not sufficient to fully exploit the full potential of high-density briquettes from sawdust admixture. Consequently, more studies are required for its characterization. This work investigates the  novel combustion characteristics of briquettes produced from composite sawdust under steady-state experimental conditions.

  1. MATERIALS AND METHOD

Briquette samples: In this study, samples of high-density briquettes (Figure 1) produced from sawdust admixture at 12%, 10%, and 8% particle moistures using a screw press extruder.

Briquette stove: As noted by Bello et al., (2013), the effects of smoke around the cooking environment make existing stoves environmentally unfriendly and uncomfortable during cooking. Therefore,  a  focused effort on stove design and technology, and other factors needed to deliver the health and climate benefits associated with reducing the emissions and improving the health of citizens and their economic and social impacts (Bello et al., 2013) necessitated the development and testing of an updraft high-density briquette/ biomass stoves (Bello et al., 2019).

Figure 1: Briquette samples and stove used for the test

  1. METHODOLOGY

A measured quantity of briquettes was burnt and two recommended performance  tests:  (water boiling test (WBT) and controlled cooking test (CCT)) to evaluate quantitative and qualitative information about the fuel combustion characteristics and stove performances(Stewart, 1987) .

Water boiling test (WBT): Dry weights of experimental materials like pot and stove were taken and recorded. The pot was filled with an initial known weight of water and the same weight was maintained throughout the course of the experiment. The water temperature data was recorded at intervals of five (5) minutes until the moment the water came to a vigorous boil.

Controlled cooking test (CCT): Controlled cooking test was carried out with rice and yam and the performance characteristics of the briquettes in the stove. When the cooking was properly done, the mass of the cooked yam and time to achieve cooking were recorded with the aid of a stopwatch.

Statistical analysis tools and models: Statistical analysis was carried out  to verify the significance  of the variations in the selected briquettes. The model parameters were estimated using SPSS

16.0 program (Release 16.0.0 for Windows) and Excel (Microsoft Corp., 2003) software to establish relationships between briquette burn characteristics. The effects of briquette density and moisture content on the burn characteristics of the briquette was done to determine the level of significance of each parameter on measured variables.

Correlation analysis was used to examine the relationship among the variables to provide a standard index of variability between the correlation coefficients.  Regression analysis  was also carried out to establish the relative contributions of briquette density, and material moisture in the prediction of the combustion characteristics of each briquette. The results of the unstandardized (β) and standardized Beta (B) regression coefficients, multiple correlation coefficient (R), adjusted R2, and its associated p values for each of the variables that suggest whether the generated regression model is a  good predictor of briquettes’ properties or not (Mitchual et al., 2013) were determined.

Performance test variables and equations: The variables used in the calculation of stove and briquette parameters were based on the approach used by FAO (1990), Ahuja et al. (1997) and Olorunisola (1999). Four sets of variables used in the evaluation of test procedures are as follows:

  1. Briquette burn rate: The procedure for the determination of briquette burn rate employed by Onuegbu et al. (2012) and Bello et al. (2015) was adopted in the experiment. Briquette sample of known weight was ignited with a burner and the weight loss measured every 10 seconds throughout the combustion process using a stopwatch until constant burnt weight  was obtained. The weight loss at specific time was computed from the expression:

Burn rate =   Total weigℎt of burnt briquette (kg)/Total time taken (hr)                                           1

                                                   

ii  Time spent in cooking per kilogram of cooked food (Ts):  Ratio  of time spent in  actual cooking to  the total weight of the cooked food.

Ts =   Total time spent in cooking (hr)/Total weight of cooked food (kg) (hr/kg)                            2

iii Specific fuel consumption: Specific fuel consumption is defined as the amount of solid fuel equivalent used in achieving a defined task divided by the weight of the task. It can be expressed as:

iv  Thermal efficiency (): Thermal efficiency is a measure of the proportion of the total energy which  is gainfully employed in any thermody-namic system. This is a ratio of the work done by heating and evaporating water to the energy consumed by burning wood. According to Clarke (1985) the thermal efficiency of a cooking stove depends largely on how well the heat generated is transferred from hot gas fuel line to the pot or vessel on the stove (convective heat transfer). Thermal efficiency is calculated from the percentage heat utilized (PHU) given by:

  1. RESULTS

4.1 Briquette burning characteristics 

Free air and stove combustion tests were used to determine the briquettes burn characteristics. Each briquette was ignited by lighter and supplemental fuel (kerosene) enough to ensure the whole of the surface of the briquette was ignited simultaneously.  Figure 2  shows the different stages of combustion processes from ignition to burnout. Figure 2(a) is the ignition phase, fire establishment can be observed burning around the briquette, Figure 2(b) & (c) are phases in the flaming combustion stage (d), is at the end of flaming combustion (burnout), and finally, in stage  (e), there is no flame and the briquette decomposes purely by char combustion.

Figure 2: Flame propagation of briquette in stove combustion chamber

After igniting the lighter was removed, the combustion proceeded with flame heights of up to 46 cm. From this preliminary observation, it was evident that the  designed  combustion chamber could contain the flame height within the chamber as seen from Figure 2.

 4.2 Briquette mass reduction rate

Table 1 shows the rate of each briquette reduction by mass consumed during burning. Mass loss was recorded for each briquette burnt at intervals until the mass of the briquette was 5% of its initial mass (Chaney, 2010).

Table 1: Mass of materials consumed in stove and normalized mass

Time

(hr)

Mass of Fuel (kg)       Normalized Mass        Briquette Length (m)

12%

10%

8%

12%

10%

8%

12%

10%

8%

0.00

1.05

1.09

1.60

1.00

1.00

1.00

0.90

0.90

0.90

0.17

0.96

1.01

1.49

0.91

0.93

0.93

0.78

0.74

0.70

0.33

0.88

0.90

1.40

0.84

0.83

0.88

0.67

0.62

0.59

0.50

0.76

0.78

1.27

0.72

0.72

0.80

0.52

0.47

0.45

0.67

0.62

0.66

1.16

0.50

0.61

0.73

0.47

0.38

0.32

0.84

0.47

0.57

1.08

0.45

0.52

0.68

0.38

0.27

0.21

1.01

0.34

0.45

1.0

0.32

0.41

0.63

0.28

0.22

0.15

4. 3 Effect of density on NBR

The impact of mass-volume reduction on density is shown in Table 3 to find relationships between reduced mass and density of all test samples.

Table 3: Effect of mass-volume reduction on briquette density

Time (hr)

Mass of fuel (kg)

Reduced volume of briquette

Reduced density of briquette

12%

10%

8%

12%

10%

8%

12%

10%

8%

0.00

1.00

1.00

1.00

1.49

1.49

1.49

0.71

0.73

1.07

0.17

0.91

0.93

0.93

1.29

1.22

1.16

0.74

0.83

1.29

0.33

0.84

0.83

0.88

1.11

1.02

0.97

0.79

0.88

1.44

0.50

0.72

0.72

0.80

0.98

0.78

0.74

0.78

1.00

1.72

0.67

0.50

0.61

0.73

0.82

0.63

0.53

0.76

1.05

2.19

0.84

0.45

0.52

0.68

0.63

0.45

0.45

0.75

1.27

2.40

1.01

0.32

0.41

0.63

0.46

0.36

0.25

0.74

1.25

4.00

4.4 Briquette performance characteristics in stove

The briquette was tested in a special briquette stove to determine the variations in time required to raise water temperature to 100 °C in water boiling test (WBT) and time taken to boil specific quantity of food  in controlled cooking test (CCT)

Figure 3: Water boiling and cooking test setups

4.5 Briquette burn rate determination in boiling water (WBT) 

The summary of results of water boiling test (WBT) and controlled cooking tests (CCT) using each briquette sample in order to  determine briquette consumption (burn rate) in briquette stove is presented below in Table 4 and 5. The controlled cooking tests (CCT) were conducted under various conditions for two varieties of food; rice and yam, respectively were presented in  Table 5.

Table 4: Water boiling test (WBT) performance results

Parameter

12%

10%

8%

Time before fuel reaches steady burning (min)

3.35

7.23

2.32

Time spent to boil 1.5kg of water to 100 C (hr)

0.14

0.09

0.07

Total time spent for total fuel combustion (hr)

0.69

0.78

0.90

Mass of consumed fuel (kg)

1.62

1.09

1.05

Burn Rate (kg/hr)

2.35

1.34

1.17

Table 5: Controlled cooking test (CCT) performance results with rice and yam

Parameters

12%

          10%

8%

Initial mass of raw food (kg)

1.00(1.00)

1.00(1.00)

1.00(1.00)

Final mass of cooked food (kg)

2.39(2.33)

2.38(2.45)

2.40(2.35)

Initial mass of fuel before cooking (kg)

1.60(1.60)

1.09(1.09)

1.05(1.06)

Final mass of fuel after cooking (kg)

0.60(1.04)

0.40(0.40)

0.71(0.43)

Mass of consumed fuel (kg)

1.00(0.56)

0.69(0.69)

0.34(0.62)

Total time spent for cooking (hrs)

0.66(0.39)

0.62(0.34)

0.54(0.31)

Burn Rate (kg/hr)

1.52(1.44)

1.11(2.03)

0.6(2.00)

5.6 Stove performance evaluation

The performance of the stove was evaluated by determining its specific fuel consumption (SFC)

and thermal efficiency and the result presented in Table 6.

Table 6: Performance evaluation of each briquette parameters

Parameters

12%

10%

10%

Specific fuel consumption (SFC)

0.75

0.68

0.61

Thermal Efficiency (TE) (%)

34.56

52.64

64.38

  1. DISCUSSIONS

Briquette burning characteristics: Briquette self-ignition time in open air and stove was low, but when supported with little quantity of kerosene, it burns with a steady flame. Each briquette retained its shape during burning and did not expand, hence lasts significantly longer compared to medium or low-density briquettes. The flame characteristics of the burning briquette revealed a progressive  smoldering within  the briquette hole, followed by a growing yellow flame at the periphery and simultaneous blue flame within the center hole. This flame propagates into high yellow flame with a brilliant white flame at the center and glowing flame at the surrounding. As the briquette burns out, the flame degenerates and gradually dies off as char combustion set-in.

Briquette mass reduction rate: Briquettes with lower burn rates have better performance than those of high burn rates which burn out within a short time.

The gradients of the steady-state combustion phase for each briquette were plotted to find the normalized burn rate (NBR) for each briquette according to equation 5 is shown in  Figure 4.

                                  NBR = Be–þX        5

Where

x = the density in kg/m3

B = exponential frequency factor is a function of briquette burn time in hours.

þ= constant determined for briquette by a least-squares fit of Equation 5.

The exponential equations for each of the lines are: For 12%, 10% and 8% MC briquettes respectively:

NBR = 1.1003e–1.128s        6

NBR=1.0924e–0.938s                                                                                           7

NBR = 1.02775e–0.526s        8

An exponential function for each curve shows that the least-squares fit line is satisfactory.

To determine the values of B and β for each of the three normalized burn rates of briquette, the mean value for the constant β was determined for each briquette samples as shown in Table 7 which gives a mean of 0.864±0.002 for the sawdust briquettes burnt and the normalized burn rate (NBR) for the briquette expressed as:

                    NBR = 1.0632e–0.864s        9

Table 7: Values of B and β for briquette moisture on NBR

MC (%)

B(hr-1)

β

    12

1.1003

1.128

10

1.0624

0.938

8

1.0275

0.526

Mean

1.0632

0.864

Figure 4: Plot of phase burning of each briquette and burn rate

Effect of density on NBR: The relative importance of density on the normalized burn rate is required to understand the degree to which each factor is needed to be controlled in briquette manufacture. The normalized burn rate was determined and a least-squares fit of the normalized mass was plotted against  the density (Figure 5a).

Figure 5: Effects of briquette density on a) NBR and b) total burning time (TBT)

The trend in Figure 5(a) indicates that normalized burn rate increases with an increase in briquette density. After an exponential fit on the scattered plot of NBR versus density, values of constants B and β were estimated for the curve by regression analysis as B=0.501 and β = −0.001 the NBR equation for the exponential curve is:

                            NBR = 0.501e–0.001s        10

From the equations, the NBR shows a clear tendency to decrease as the density increases, as predicted from literature (Chaney, 2010). The result shows the significance of density on normalized burn rate; higher density briquettes have a lower normalized burn rate.

Effect of density on briquette total burning time: Considering the total time taken to burn the whole briquette starting from the initial mass to the maximum mass loss (approximately 5% of initial mass (Mandal et al., 2012) to determine the total burning time (TBT), a plot of time against density (Figure 5b) gives a good estimation of (TBT). An exponential regression analysis provided the best fit curve with the regression equation (11) predicting the total burning time at a given density:

                            TBT = 0.002e–0.008s                                11

The result indicates that high briquette density was responsible for slow flame propagation resulting in longer burning time. By implication, the higher density briquette takes more time to burn out while a lower density briquettes took shorter time but reach burning phase 2 faster than higher density briquettes.

Effect of briquette density on burn rate: It is equally significantly important to note that the density of briquette increases as the mass to volume ratio reduces. The impact of mass-volume reduction on density is graphically illustrated for briquette samples in Figure 6 and these show some inverse relationships between reduced mass and density of all test samples with significant correlations in lower moisture briquettes: (0.0413, 0.969 and 0.948) for 12%, 10%, and 8% briquettes respectively.

Briquette burn rate in boiling water (WBT) and control cooking tests (CCT): From Table 4, it takes a shorter time (0.07hrs), to boil 1.50kg of water with 8% moisture content briquette, and consuming 1.05kg of fuel, while it takes longer time (0.9<0.78<0.07) hrs to consume the relatively same quantity of fuel for other briquettes.

Figure 6: Effect of burn rate on mass reduction and density of 12%, 10% and 8% briquette

The rate of burning of each briquette in the stove significantly varied. The burn rate values decrease with an increase in feedstock moisture content. The implication of this is that more fuel is required for cooking with briquettes produced from higher moisture briquettes than for low moisture briquettes. Variations in the amount of briquette do not significantly affect the resulting  burn rates in the cooking of each food. Total time spent in burning off the fuel varied at each stove but maintained a time range of 32-39min. Time spent in cooking rice and yam were as indicated in each operation. Relatively, the time spent in cooking ~1 kg of food; rice (yam) is not significantly different for all the briquettes burnt in the stove (minimum 0.54/0.31 hrs. for 8% moisture briquettes and maximum 0.66 (0.39) hrs. for 12% moisture briquettes). The practical implication is that a lesser quantity of 8% moisture briquettes will be required to cook the same quantity of food compared to the 12% moisture briquettes.

Stove performance evaluation: from the results, the stove has different thermal efficiencies and specific fuel consumption (SFC) when tested with different briquette samples. The result of the thermal efficiency and the average specific fuel consumption of the stove obtained from the experiment are (64.38%,  52.64% and 34.56%), and (0.6, 0.68, 0.75) kg/hr. for 12%, 10% and 8% briquette samples respectively. The thermal efficiency of the stove increases with an increase in briquette material moisture content while the specific fuel consumption increases with a decrease in moisture content. This result implies that stove performance characteristics are largely dependent on fuel material quality. Equally, from the result, it is evident  that the fuel burn rate has  a significant effect on the stove’s thermal performances. The ability to control fuel burn rate is therefore essential if thermal stove performances are to be optimized and that there is an optimum fuel burn rate that could give maximum stove efficiency for a given configuration (Kandpal et al., 1994).

  1. CONCLUSION

Form the experimental considerations; the briquette burn characteristics improves with increase in briquette quality. Burn rate increased for briquettes produced at lower moisture content, and reduced for higher density briquettes. Briquette combustion characteristics are dependent on the environmental conditions under which it is burned and also  on the medium in which they are burned.  Briquette burn rates vary from open-air burning, to controlled air (stove) burning. The briquette stove’s thermal efficiency is dependent on the quality of fuel. There is an inverse relationship between specific fuel combustion and thermal efficiency of the stove. The higher the briquettes particle moisture,  the  higher the specific fuel combustion and the lower the stove thermal efficiency and vice versa.

Conflict of Interests

The authors declared that there is no conflict of interests regarding the publication of the article..

REFERENCES

  1. Adegbulugbe AO, 1994. Energy-environment issues in Nigeria. International Journal of Global Energy Issues 6(12):7-18.
  2. Ahuja DF, Joshi V, Smith KR, Venkataraman, C, 1997. Thermal Performance and Emission Characteristic of Unvented Biomass-Burning Cookstove. Standard Methods for Evaluation. Biomass. 10:12.
  3. Ajiboye TK, Abdulkareem S, Anibijuwon AOY, 2016. Investigation of Mechanical Properties of Briquette Product of Sawdust-charcoal as aPotential Domestic Energy Source. J. Appl. Sci. Environ. Manage. Dec. 2016 Vol. 20 (4) 1179-1188. https://dx.doi.org/10.4314/jasem.v20i4.34
  4. Aremu MO, Agarry SE. 2013. Enhanced Biogas Production from Poultry Droppings using Corn Cob and Waste Paper as Co-Substrates, International Journal of Engineering Science and Technology; 2013 Vol. 5 No. 2 pp 247-253.
  5. Bello RS, Adegbulugbe TA, Onilude MA, 2015. Characterization of three conventional cookstoves in south eastern Nigeria. Agric Eng Int: CIGR Journal. 17(2):122-129http://www.cigrjournal.org/index.php/Ejounral/article/view/3037/2106
  6. Bello RS, Odey SO, Saidu MJ. 2019. Development and comparative evaluation of three high-density biomass stoves and clay-lined charcoal stove. Proceedings of the 20th International Conference and 40th AGM of the Nigeria Institution of Agricultural Engineers (NIAE), Landmark University, Omu-Aran, Nigeria. Pp 1349 – 1358.
  7. Bello RS, Okafor EC, Ezebuilo CN, Bello MB, Umahi O, 2013. Cookstove technologies and environmental impacts in the South-eastern Nigeria. In Sustainable Environmental Management: Issues & Projections. Eds Bello R. S. Balogun R. B. & Okereke S. N. ch 21. 275-299. Createspace, Charl US. ISBN-13: 978-149-285-349-7https://www.createspace.com/4462554
  8. Chaney J, 2010. Combustion Characteristics of Biomass Briquettes. Unpublished PhD thesis submitted to the University of Nottingham.
  9. Chin OC, Siddiqui KM, 2000. Characteristics of Some Biomass Briquettes Prepared Under Modest Die Pressures. Biomass and Bioenergy. 18, 223-228.
  10. Clarke R., 1985. Wood-stove Dissemination. Proceedings of the Conference held at Wolfheze, The Netherlands. Intermediate Technology Publications, 9 King Street, London. pp 97-102.
  11. Faizal H. M., Latiff Z. A., Mazlan A. Wahid, Darus A. N., 2011. Physical and Combustion Characteristics of Biomass Residues from Palm Oil Mills. New Aspects of Fluid Mechanics, Heat Transfer and Environment. ISSN: 1792-4596 ISBN: 978-960-474-215-8, 34-38

  1. FAO 1990. The briquetting of agricultural wastes for fuel: Environment and Energy paper, vol. 11. FAO, Rome.
  2. Husain Z, ZA, Zainal, MZ Abdullah, 2002. Briquetting of palm fiber and shell from the processing of palm nuts to palm oil. Biomass and Bioenergy 22(6):505-509 DOI: 10.1016/S0961-9534(02)00022-3
  3. Kandpal JB., Maheshwari RC, Kandpal TC, 1994. Air pollution from biomass combustion in domestic cookstove. Renewable Energy, Vol. 4. No. S. pp. 54S--S49. 1994
  4. Križan P., Miloš M, Ľubomír Š and Beniak J., 2015. Behaviour of Beech Sawdust during Densification into a Solid Biofuel. Energies 8, 6382-6398; doi: 10.3390/en8076382 ISSN 1996-1073 www.mdpi.com/journal/energiesInternational Energy Agency (IEA), 2002. Africa key Energy Statistics http://www.iea.org  Accessed October, 2010.
  5. Li, T., 2003. Development of Plastic Waste Disposal Method by Combustion of Coal Briquette. Department of Ecology Engineering, Toyohashi University of Technology.
  6. Lim MT, 2007. Characterization of a Bubbling Fluidized Bed Biomass Gasifier. MSc thesis Universiti Sains Malaysia. Pp 1-44.
  7. Mitchual JS, Kwasi F, Darkwa NA, 2013. Effect of species, particle size and compacting pressure on relaxed density and compressive strength of fuel briquettes. Int J Energy Environ Eng (2013) 4: 30. doi:10.1186/ 2251-6832-4-30
  8. Olorunnisola AO, 1999. The efficiency of two Nigerian cooking stoves in handling corncob briquettes. Nigerian Journal of Renewable Energy 7(1&2): 31-34.
  9. Olorunnisola AO, 2007. Production of fuel briquettes from waste paper and coconut husk admixtures. Agricultural Engineering International, Vol.IX, article EE06066, 2007.
  10. Onuegbu TU, Ekpunobi E, Ogbu IM, Ekeoma MO and Obumselu FO. 2012. Comparative studies of ignition time and water boiling test of coal and biomass briquettes blend.  International Journal of Research & Reviews in Applied Sciences, Vol.7, pp.153–159, 2012.
  11. Qian K., Kumar,  Patil A, BellmerK, , Wang D,  YuanD,  HuhnkeW, RL, 2013. Effects of biomass feedstocks and gasification conditions on the physiochemical properties of char. Energies, 6, 3972–3986.
  12. Risović A, Dukić, I, Vućković, K., 2008. Energy analysis of pellets made from wood residue. Croat. J. for. eng. 29 (2008) 1, pp 95-105.
  13. Salunkhe DB Rai RK, Borkar RB., 2012. Biogas Technology, International Journal of Engineering Science and Technology; (4) No.12 pp 4934-4940.
  14. Stewart, W., 1987. Improved Wood, Waste and Charcoal Burning Stoves. A Practical Manual. Intermediate Technology Publi- cations, Covent Garden, London, UK.



author

For Authors

Author Membership provide access to scientific innovation, next generation tools, access to conferences/seminars
/symposiums/webinars, networking opportunities, and privileged benefits.
Authors may submit research manuscript or paper without being an existing member of LJP. Once a non-member author submits a research paper he/she becomes a part of "Provisional Author Membership".

Know more

institutes

For Institutions

Society flourish when two institutions come together." Organizations, research institutes, and universities can join LJP Subscription membership or privileged "Fellow Membership" membership facilitating researchers to publish their work with us, become peer reviewers and join us on Advisory Board.

Know more

subsribe

For Subscribers

Subscribe to distinguished STM (scientific, technical, and medical) publisher. Subscription membership is available for individuals universities and institutions (print & online). Subscribers can access journals from our libraries, published in different formats like Printed Hardcopy, Interactive PDFs, EPUBs, eBooks, indexable documents and the author managed dynamic live web page articles, LaTeX, PDFs etc.

Know more