Bagasse an Alternative Fuel? Why not!

We have seen from one of my previous post titled ‘Composite fuel briquettes : Converting agricultural waste (Bagasse) into Charcoal’ and my blog on sdsanbhatshareslearnings.blogspot.com that any agricultural wastes would be unsuitable to be used directly in as is available form on account of serious health and environmental problems ensuing thereof. It needs to be converted into a solid or liquid form for its efficient use. In this post we learn on one such traditional agricultural waste i.e. bagasse and decide on the need to unlearn/relearn the same as regards its suitability today as an alternative fuel.

Abstract
We attempt to learn through somewhat of an extensive online literature/statistical survey on bagasse based on;

o   Properties: In order that the agricultural waste like bagasse could be used as an alternative fuel, one needs to firstly ascertain their comparative value in terms of dry heat content availability with the commonly used commercial fuel forms of coal, petrol, LPG, etc.    

o   Availability: In order that the agricultural waste could be used as an alternative fuel, one needs to ascertain not just in the sense of numbers or tons availability but something beyond it too.

In this technical post, we therefore conclusively intend to ascertain the true nature of agricultural wastes such as bagasse as an alternative fuel but also to them being really a renewable energy source while probing at that 'something beyond' aspect mentioned above. 

Introduction

What is BAGASSE?

Sugarcane has been a seasonally-grown food and feed crop, the processing of which creates bagasse, a low-cost biomass material, as its by-product. Bagasse is a commodity that is readily available for use — since 2002, more than 610 million tons of bagasse was produced worldwide. It is suitable for production of energy, ethanol, animal feeds, paper products, composite board, and building materials; and it is a feed stock for fluidized - bed production of a range of chemicals.

Selection of biomass and waste as an alternative fuel

Renewable Energy Program- Govt. of INDIA

Since the availability of fossil fuel has been on the decline and use of the same inflating the adverse impact on environment and ecology, the conception of bagasse combustion as a sole means of solid waste disposal has changed. Therefore in this backdrop the norms for renewable sources of energy (RSE) were given importance not only in India but has attracted the global attention.

The main items under RSE are as follows:

i)                   Hydro Power

ii)                Solar Power       

iii)              Wind Power

iv)              Bio-mass Power

v)                Energy from waste

vi)              Ocean energy

vii)           Alternative fuel for surface transportation

Discussion

A.   Properties

Physical properties;

1.     White & light green.

2.     It is odourless.

3.     The typical specific weight is 250 Kg/m3.

4.     The main content: - 45% moisture, 50% cellulose - (27.9% hemi cellulose, 9.8% lignin & 11.3% cell contents) & 6% others.

5.     Energy content: - 19400 KJ/Kg dry ash free.

Chemical properties;

The percentage distribution by dry wt. of major elements composing the bagasse is present in the below table.

Chemical formula: Estimation of the chemical formula of bagasse;

     1)The percentage distribution of the elements with & without the water contained:      

     Given: - 100 Kg bagasse based on 45% of moisture content.

 2)Computering the molar composition of the elements neglecting the ash component:

3)Setting up the computation table to determine the normalized mole ratio:

4)    Approximate chemical formula of bagasse:

               Without water : - C₁₁₂₅H₁₈₀₀O₇₃₅N₄S

               With water      : - C₁₁₂₅H₄₂₅₀O₁₉₈₅N₄S

Bagasses are the fibrous residue of the cane stalks after crushing & consist mainly of cellulose, pentosans & lignin. Its final composition after milling depends on method of harvesting as well as age & type of cane. On average it is assumed to have 50% moisture, 47.7% fibre & 2.3% soluble solids.

B. Overview of sugar industries

Dry matter productivity of some selected agricultural crop;

Sugarcane bagasse has been reported to contain 48% cellulose. It thus implies that the total world production of 233.942 million tons of bagasse from 15,895 hectares would yield 112.29 million tons of cellulose. These data indicate that based on per unit of land area sugarcane was the most productive cellulose producing crop. The majority of bagasse produced in small or large scale factories has been generally used as fuel in the same factory where it was produced to generate steam & electricity.

Sugar industries scenario in INDIA;

Sugar industry has been the second largest industry after textile in India. India also stands among the first five countries of sugar production in the world. The annual turnover of the sugar industry has been around 5500 crores of rupees and the total investment is around 3500 crores of rupees. It also employs directly or indirectly of about 1.75 crores people in India as is evident from the crushing capacity of sugar mills that vary from about 1500 - 5000 tonnes per day. Sugar cane synthesis the maximum solar residue and energy into biomass like sugar, cellulose, lignin and pentosans.

     Profile of Indian sugar Industry;

The statistics given below are quiet old but the latest could be availed from references cited at the end of the post.

The sugar companies comes under the Board of Industrial & Financial Reconstruction (BIFR). As per the information provided by the BIFR as on 30-06-2003, 44 companies involving 76 sugar mills were registered with BIFR. 

Some more overview of the sugar industries are presented as shown below:

• Sugar Statistics – India

Indian sugar industry at a glance:

•         Sugar Statistics – Maharashtra

Maharashtra sugar industry at a glance

•         Sugar Statistics – World

Bagasse production (most recent) by country

Conclusion

Total bagasse estimated production in the world (Year 2005) : 407,213,347 tons 

Based on the above available figure the amount of bagasse that could be channeled as an renewable source of energy is tremendous as seen from the below comparison.

High Calorific Value (HCV) or Gross Calorific Value (GCV) of coal is 15000 – 27000 KJ/KG

HCV or GCV of dry ash free bagasse is 19400 KJ/ Kg

HCV or GCV of fuel oil is 41200 KJ/L

HCV or GCV of LPG is 94000 KJ/M³

   

1 ton of bagasse = 1 barrel of fuel oil =  0.173 ton of fuel oil

1 tonne LPG = 8.46 barrels of fuel oil equivalent =  8.46 tonnes of bagasse

1 ton coal = 3.4 tons bagasse

The current price of Indian coal is $22-23 (approximately Rs.1250 ) a tonne

Bagasse is worth between Rs.690 and Rs.725 per tonne (mill-run weight, 50 percent moisture content) and a figure of Rs.750 could be used as a rounded representative average

LPG at Rs.24000 per tonne

Fuel oil is rated at Rs.3500 per barrel

One kg of bagasse can generate 3.12 kg of steam in steam generators

One kg of coal can generate approximately 8kg of steam

Approximately 15 kg of steam can be produced from 1 kg of oil, or 14 kg of steam from 1 litre of oil

Approximately 42 kg of steam can be produced from 1 Therm of gas i.e. Natural gas  & Liquefied petroleum gases (LPG)

1 ton of coal can generate about 1500 kwh of electricity

1 barrel of fuel oil can generate about 1700 kwh of electricity or one gallon of crude oil can produce about 17 kWh

1 ton cane crushing can produce 100 KwH of electricity where one ton of sugarcane, yields about 250 kg of bagasse

1 therm of natural gas = 29.3 kWh of electricity where 1therm = 100 cubic feet = 2.265 kg

  

For the next post, let us delve into the 'something beyond factor' i.e. the procurement cost feasibility for bagasse (as also other agricultural wastes too) as highlighted below without which the practicality of being renewable would be only on paper inspite of them having good properties and tons in availability.

1.  The localized availability aspect in comparison with the commercial fuels’ centralized mining/production   

2.  The availability aspect in comparison with the commercial fuels’ excellent transportation and distribution channels post mining/production

3.  The sustained availability in terms of renewable in nature i.e. could it offset the inherent excellent properties of the commercial fuels and their centralized mining/production systems?

 
References

[1]   D.S Chahal. “Food, Feed & Fuel from Biomass”, reprint    1991, pp.23.

[2]   N.H. Ravindranath, K. Usha Rao, Bhaskar Natranjan. “Renewable       Energy & Environment”, 2nd reprint 2000 pp.106, 242.

[3]   L.A Ekal, S.H Pawar. “Advances in renewable energy   technologies”, 1^st reprint pp.35, 194.

[4]   S. Rao, Dr. B.B. Parulekar. “Energy Technology”, 2nd edition, 1997.

[5]   G.D Rai. “Energy Resources”, 3rd edition, 1999.

[6]   http://164.100.24.208/Is/committeeR/Food/27.pdf

[7]   http://bioproductsbioenergy.gov/pdfs/bcota/abstracts/30/z130.pdf

[8]   http:// Polystyrene#Environmental impact

[9]  www.springerlink.com/index/232k30g002472824.pdf

[10] http://www.vsisugar.com