Th3_Particle size, drying method, water temperature and husk-to-bran ratio are important factors influencing the hardness of briquettes at constant pressure

Particle size, drying method, water temperature and husk-to-bran ratio are

important factors influencing the hardness of briquettes at constant pressure

S.A. Ndindeng, J.E.G. Mbassi*, M. Bih-Loh Achu, W.F. Mbacham, J.T. Manful

[email protected]

IntroductionIn regions of the world where rice is produced especially in SSA countries, poor treatment and disposal of rice by-products is a serious problem as this results in pollution.

In these communities rubber roll mills are advantageous not only because they produce better quality milled rice but also because they produce separate husk and bran

PolishingDe-husking

Rubber roll mill

IntroductionRice bran is often used in in SSA countries as an ingredient in the production of livestock feed.

Recently some authors have pointed out the possibility of using rice bran as a supplement in the production of biscuits and cookies (Bunde, 2010; Yadav, 2011).Unlike the bran, rice husk is not used for any purpose in SSA countries and the huge mounts behind rice mills is usually set on fire and it burns slowly as it is produced.

Some authors have indicated the possibility of using rice husk ash as a partial substitute for cement (Brown, 2012).

HUSK

BRAN

IntroductionHowever, in areas where Engelberg-type mills are common, the husk is usually mixed with the bran, making both by-products unsuitable for livestock feed production.

Briquetting of husk from rubber roll mills and husk mixed with bran from Engelberg mills for fuel wood has been suggested as alternative means to add-value to these by-products especially for communities that need fuel wood for other rice processing activities such as parboiling.

Such a briquetting process must also ensure that it does not incorporate material in the briquettes that will render the ash unusable either as a cement substitute or in ceramics.

De-husking and Polishing

Briquettes

ObjectivesOverall To add value to husk and husk mixed with bran through briquetting to achieve the required hardness and burning parameters.

Specific• Produce a briquetting machine• Use machine to produce briquettes while varying the following

factors:• Particle size• Husk : Bran ratio• Water temperature• Drying method

• Measure the hardness of different briquettes

Methodology of briquette productionBiomass

collection

Grinding

Mixing

Briquetting (press)

Drying

Strength analysis on briquettes

Water[Hot = 97 oC] [Cold = 27oC]

•Open –air•In the oven (70°C)

Husk

Bran

Sieving Large, Pore size (mm2) = 2<PS ≤ 67Medium Pore size = 0,49<PS ≤2Fine, Pore size = PS ≤ 0,49

Ratio

Results and Discussions

Support

Piston

Pressure pump

Lid Cylindrical tube

Bar

Lever Open/closed pump

Hydraulic Pump briquetting machine (2 tons)

•Influence of proportion of husk and bran on the hardness of briquettes

More bran leads to harder briquettes

Drying method= Sun, Drying time = 14 days, water proportion= 1,5, water temp= hot (97°C),

Particle size =fine,

33336N =

Ratio of husk to bran

2:10:11:01:21:1

Mean

+- 2

Std

Err

Hard

ness

(Kg)

14

12

10

8

6

4

2

Sokhansanj and co-workers (2005) identified that feed material containing higher proportions of starch and protein will produce higher quality briquettes than material high in cellulosic material.

Results and Discussions

•Influence of drying method on the hardness of briquettes

Michel and Autio (2001): During drying, the amylopectin portion of the starch granule recrystallizes, and increases the rigidity of starch gels

Drying time = 7, water proportion= 1,5, water temp= hot, Particle size =fine, Ratio husk to bran=1:1

Sun drying had the best effect on the hardness of the briquettes.

32N =

Drying method

Sun onlyOven and Sun

Mean

+- 2

Std

Err

Hard

ness

(Kg)

8.0

7.5

7.0

6.5

6.0

5.5

Results and Discussions

•Influence of temperature of water used for mixture on the hardness

Warm water influence positively on the hardness of briquettes

Drying method= Sun, Drying time = 14, Particle size =fine, water proportion= 1,5, Ratio husk to bran=1:1

56N =

Water temp for briquetting (oC)

Cold (27)Hot (97)

Me

an

+-

2 S

td E

rr H

ard

ne

ss

(K

g) 10

8

6

4

2

0

Results and Discussions

Hot water modifies physico-chemical properties (gelatinization of starch, denaturation of protein) and binding between particles is greatly enhanced resulting in improved physical briquettes quality (Thomas et al. 1997)

•Influence of Particle size on the hardness of the briquettes

Drying method= Sun, Drying time = 21, water proportion= 1,5, water temp = hot, Ratio husk to bran=1:1

33N =

Particle size

MediumFine

Mean

+- 2

Std

Err

Hard

ness

(Kg)

12

11

10

9

8

7

6

5

4

Mani and co-workers (2003) report that smaller particle sizes produce higher density briquettes.

Fine Medium Large

Results and Discussions

Conclusions and Recommendations• Husk-Bran mixture of 1:1 from Engelberg mills and husk alone

(1:0) from rubber roll mills gave briquettes of good hardness (7-9 kg).

• The highest hardness were achieved from a combination of the following factors:

Drying method: Sun drying/Open air

Water temperature: Hot (97°C)

Particle size: Fine (PS ≤ 0,49)

Drying time: 21 days

Combination

Thanks for your kind attention