A Feasibility Study of Power Generation from Rice Husk in Bangladesh

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A Feasibility Study of Power Generation from Rice Husk in Bangladesh

Md. Maidul Islam

Department of Electrical and Electronic Engineering Bangladesh University of Engineering and Technology

Sadi md.Shihab

Department of Electrical and Electronic Engineering Bangladesh University of Engineering and Technology

Abstract— Energy is the force behind the production of motion, work and change. Energy exists in many form such as Chemical, Nuclear, Solar, Thermal, Water, Wind, Biomass etc.

Bangladesh population is increasing and the Bangladesh has needed more electrical energy. The products quantities that use up electricity have grown rapidly. Fossil fuels have been excessively consumed. The traditional energy sources mostly used in Bangladesh are diminishing at a rapid rate thus causing energy crisis all over the country. Supply of power is less than demand in insecure situation in Bangladesh.

Considering all these barriers, Renewable energy is being looked at as an alternative for Bangladesh. Biomass from agriculture, especially rice husk, is a very promising renewable energy source since it is indigenous and is considered to have environmental benefits. In this paper, it has been put some statistical data and analyzed the data reflecting the possibility of establishing a power generation unit using Husk as a fuel.

Some problems while establishing a rice husk cogeneration plant in Bangladesh and some possible way out has also been proposed.

Index Terms— Rice husk, Renewable Energy, plant, Biomass, Bangladesh

I. INTRODUCTION

Bangladesh is a developing country. So it is very much important for Bangladesh to ensure its own energy security.

The conventional energy sources are decreasing day by day.

So now it is high time we should take the renewable energy sources in action. In Bangladesh the peak demand of electricity is 9268 MW and by the year 2021 it will be 18838 MW [1]. To meet up those demand of electricity in Bangladesh in future need alternative of conventional energy sources. Electricity generation from rice husk can be a better alternative of conventional energy sources in Bangladesh perspective. It is comparatively cheaper to install, easy to handle. In Bangladesh there are several types of obstacles to establish such kind of non conventional power plant. The approximate amount production of rice husk globally is 600 million ton [2]. The average caloric value of rice husk is 3410 K Cal/kg [3]. 1 ton of rice paddy can produce 220 kg of rice husk [4]. The impact of global warming potential of rice husk energy is far less than fossil fuels plants because CO2 from biomass is considered as greenhouse gas neutral.

Sulphur and nitrogen contents in rice husk are small [5]. So Rice Husk can be a effective fuel for power generation. In this paper first several statistical data has been analyzed using previously collected data of Husk in Bangladesh. Also suitable location area in Bangladesh to establish Husk power Plant has been studied. Some problems while establishing a rice husk cogeneration plant in Bangladesh and some possible way out has also been proposed.

II. BACKGROUNDANDMOTIVATION As of 2011, Husk Power Systems provides power approximately 25,000 households in more than 250 villages serves 150,000 people through its 60 mini-power plants systems that each generate 35 to 100 kilowatts of power in villages in india's states of Bihar, Tamil Nadu and West Bengal, providing up to eight hours of power, primarily during the evening hours when illumination is needed [5].

Dreams Power Private Ltd. (DPPL) a local sponsor has developed this project. The Plant is the first ever its kind in Bangladesh. The project was funded by IDCOL. The project started commercial operation in October 2007. As stated earlier, Dreams Power is the first endeavor in its field in Bangladesh. The first always faces the biggest challenges. Dreams Power is the one who overcame all those challenges to become first. And hence she has laid down a path for others to follow and create opportunities to be replicated. Husk can be used as a effective and alternative source of fuel to generate power in Bangladesh.

III. ESTIMATIONOFAMOUNTPOWER

GENERATIONFROMHUSK

Available rice husk estimation is necessary if we want to predict amount of power generation. We got the total rice production data from the Statistical Year Book of Bangladesh Bureau of Statistics (BBS).To estimate the available husk amount, first we convert rice production data to amount of produced paddy. Rice is approximately 67% in weight of total paddy. The blue line in Fig. 1 indicates total rice production which is divided by 0.67 to get amount of paddy production. The amount of paddy per year is indicated by the red line in the same Fig. 1. According to the studies, total amount of paddy is not available for International Conference on Materials, Electronics & Information Engineering, ICMEIE-2015

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milling process, 30% paddies are processed by the farmers themselves with the help of rural old technology. So according to this data we estimate available paddy for milling process by taking 70% of the total gross paddy indicated by the green line in the figure. Amount of husk is 20% in paddy. So we get the available husk from previous data indicated by the violet line in Fig. 1

Source: Bangladesh Rice Knowledge Bank (BRKB)

Fig. 1.Production of Total Rice, Gross Paddy, Milled Paddy, Rice Husk

This husk is mainly used in parboiling and drying for milling process. 67% husks are used in parboiling and 5%

are used in drying process. 20% of it goes to briquette production and the rest goes for poultry and pet feeding as shown in Table I.

Fig. 2.Production of Rice Husk & husk for parboiling

In Fig. 2 the total amount of rice husk is shown (indicated by the blue line) with the utilizable amount for cogeneration considering only the parboiled amount to be used (red line).

In this case, a question arises that how the parboiling is to be done if husk is used for generation. The solution to this is very simple. The heat of the exhaust gas from the power plant is enough to serve the purpose of parboiling. So actually we are increasing the total efficiency of the whole system. In Fig. 2 it is included a forecast by using mathematical calculation and simple interpolation techniques. With the help of advanced statistical methods considering various forecast techniques this approximation can be improved to a substantial amount. From the previous section it has got an idea about the surplus husk amount in our country. By increasing boiler efficiency, the amount of surplus husk can be increased. Now probable generation from husk is calculated for a 500 KW power plant in the following table I and II.

TABLE I: HUSK CONSUMPTION OF A 500 KW PLANT

Parameter Unit Data

Milled paddy / gross paddy ratio % 70 Rice husk / milled paddy ratio % 20 Husk for parboiling / total husk

ratio

% 67

Husk consumption Kg / KWh 2

Installed capacity KW 500

Operating time Hours / year

6000 Total Husk consumption tons / year 6000

Source: Statistical Year Book of Bangladesh Bureau of Statistics (BBS).

TABLE II: TOTAL POTENTIAL GENERATION OF POWER FROM RICE HUSK

Parameter Unit Data

Total Husk consumption for per KW

tons / year 12 Available total rice husk Million

tons / year

5.473 Husk for parboiling (usable) Million

tons / year

3.667 Probable generation of power MW 305.583

Possible no of 500 KW plant units 610

Based on the above calculation we show here a graph in Fig.

2 of probable power generation from the year 2000 to until now along with the estimation till 2014.

. Fig. 3.Generation of Power in present & improved condition

In Fig. 3 we see two graphs where first one is showing the probable generation of power in the prevailing condition in Bangladesh indicated by the blue line. Now we already mentioned that 70% of total paddy is taken to the mills (30% is processed in the households) and we considered only 67% of the total husk for use in power generation. If the amount of milled paddy can be increased to 80% and by using improved techniques boiler efficiency can be increased to use 75% of the total husk can be utilized, then we would be able to increase the amount of total generation by 28% and in the improved condition the generation is shown by the red line Fig. 3. In both cases of present and improved condition we show here the estimation till 2014.

IV. LOCATION SELECTION FOR HUSK POWER PLANT

To know the available quantity of rice husk in a cluster have to know the cluster size as well as paddy processing capacity of rice mills in that cluster. It has mentioned few major clusters and their size in previous subsection and now International Conference on Materials, Electronics & Information Engineering, ICMEIE-2015

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average capacity of the mills of different cluster s are tabulated as follow.

TABLE III: TOTAL AMOUNT OF PADDY PROCESSED (MT/YEAR) IN DIFFERENT CLUSTER [6]

Cluster

Annual paddy processed

(MT)

Number of rice

mills (surveyed)

Average paddy processed

(MT)

Total number

of rice mills

Total amount of paddy MT/year

Dinajpur 464480 100 4644.8 300 1393440

Naogaon 241062 134 1799.0 775 1394225

Bogra 156611 100 1566.1 110 172271

Nawabganj 91426 16 5714.1 16 91426

Ishwardi 120764 50 2415.3 50 120764

Fig. 4 Available rice husks for commercial processing in different cluster

Here it is found out average paddy processed in metric ton by a mill from surveyed data and from this estimate the total amount of paddy processed in each cluster. Quantity of rice husk is assumed as 20% of the amount of paddy and so annual husk production of these clusters would be like this, Amount of rice husk consumption during parboiling process shows a great variation due to use of traditional parboiling system with low efficiency. This variation indicates that there is a scope of saving husk if improved and efficient boiler could be used. Most of the mills consume from 100~150kg of rice husk per ton of paddy parboiling. On average, we assume 125kg of rice husk is used for per ton of paddy parboiling. Most of the mechanical dryer at rice mills use 80-115 kg husks per ton of paddy drying. On average we can assume 97kg husk is required for per ton paddy drying. We found that almost all (100%) rice mills in Naogaon and Ishwardi use sun drying. On the other hand 54%, 3% and 99% rice mills use mechanical drying in Dinajpur, Bogra, and Nawabganj respectively. So amount of surplus rice husk after parboiling and drying can be calculated as follow.

TABLE IV: USE OF RICE HUSK FOR PARBOILING AND DRYING [6]

Cluster

Available rice husk (MT/year)

Total numb

er of rice mills

Kg husk/ton paddy for parboilin

g

Kg husk/t

on paddy

for drying

Rice mills use mecha

nical drying

(%)

Dinajpur 278688 300 125 97 54

Naogaon 278845 775 125 97 0

Bogra 34454 110 125 97 3

Nawabga

nj 18285 16 125 97 99

Ishwardi 24152 50 125 97 0

Amount of surplus rice husk= A - B×C - B×D×E/100.

Here A is total rice husk output from rice mills. But rice mills use rice husk for own parboiling and drying purpose which should be deducted. Amount of rice husk for parboiling is calculated by multiply total number of rice mills with average amount of rice husk required for parboiling. For drying requirement use of mechanical drying percentage should be consider.

By this equation the amount of surplus rice husks are shown in Fig. 5

Fig. 5.Surplus rice husk or rice husk avilable for sell.

Power plant location is probably the first consideration that should be made and it should fulfill some requirements.

Rice husk availability is the main criteria for these types of power plant. Then size of power plant and process for power generation should be kept in mind.

V. PROBLEMS BEHIND THE SCENARIO Some practical problems while establishing a rice husk cogeneration plant. Now these problems might become severe if have not proper idea about them. In this section, it has been discussed the problems behind the scenario.

A. Increase in cost of Rice Husk

At present rice husk is available at a very cheap rate.

Another reason behind the present cheap rate is that now we don’t use husk appropriately and the most of it is left as the cattle food without any proper treatment. But if rice husk cogeneration plants are established, then there will be a high competition in the market and then the price of husk will International Conference on Materials, Electronics & Information Engineering, ICMEIE-2015

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surely go up. Now if the price goes up beyond limit, it would be a serious problem for the investors.

B. Possibility of Artificial Crisis of Husk during Peak Time of Year

In Bangladesh, it is a common practice to create artificial crisis of goods or services during the period when people need it most. This is done by some corrupted but powerful businessmen throughout the country. If rice husk is used as the fuel for plants, then the price of it will grow up.

C. Problems for Poultry & Pet Feeding

At present, Rice husk is an inexpensive byproduct of human food processing, serving as a source of fiber that is considered a filler ingredient in cheap pet foods. But if we start using as a fuel for power generation plant, apparent raise in its price will force the poor farmers to leave it as pet food and sell all the extra husk that they could effort previously for their pets.

D. Electrical Problems

The electrical load is different for parboiling system, drying system, milling system, lighting and other. So it is likely that the demand varies from time to time during different hours of the day.

V. SUGGESTIONS TO SOLVE SOME PROBLEMS To solve the above mentioned problems, we hereby include some suggestions that believed to be helpful in this regard.

A. Assuring Stability of Cost of Rice Husk

Cost of Rice Husk is an important issue for plant set up. The Govt. and the people concerned should be careful of this fact. There should be a monitoring committee which might work to ensure that the market price of the husk is stable. In reality, it is sure that the price is to go up if bulk portion of husk is used as fuel, but the committee has to make sure that it is not over the limit or beyond the scope of the budget for fuel cost of the investors. This cannot be accomplished single handed by the Govt. only, public concern is also very important in this regard.

B. Govt. Intervention to stop Artificial Crisis of Husk To prevent the activities of corrupt groups, the investors and the Govt. should keep a close eye on the market. The monitoring committee should always keep an eye on the listed businessmen. People should be made aware about the market policy of the Govt. about the buying and selling of rice husk very clearly. We should also make sure that no single person or business organization is buying out a lot of husk without selling them.

C. Control over Poultry food Price

With the increasing use of husk as fuel, less portion of it will be used as the poultry or pet food. So the farmers will have to look for other food options. Now there is a possibility that poultry and pet food manufacturers may try to manipulate this condition by increasing the price of their products. To prevent this, the Govt. has to take strong

measures and the monitoring committee has to also provide a section of its work force in this regard.

D. Recruiting Briquette Production Workers in Power Plants

Increase of the use of husk as a fuel in cogeneration plants will hamper the briquette production industry. As a result, a number of workers in these industries is likely to lose job opportunity. To fight this problem, we might use this work force in the husk base cogeneration plants.

VI.CONCLUSION

Geographical condition of Bangladesh is favorable for rice production and currently a lot of rice husk is being used inefficiently whereas the countries like Vietnam, Thailand, China are using this opportunity to generate power at comparatively low cost. Bangladesh produces almost about 26 to 27 million tons of rice per year presently. 70% of the total paddy goes to the rice mills and the total husk can be approximated to 5.2 to 5.4 million tons per year.

Considering only 67% of it can be used for power generation, we can produce about 300 to 320 MW power at present. If the amount of milled rice can be increased to 80% from 70% and 75% of total husk can be utilized by increasing efficiency in the system, then the total generation can be increased to about 28% and 370 to 400 MW power can be produced. Some practical problems while establishing a rice husk cogeneration plant. To solve the above mentioned problems, it is proposed some suggestions that believed to be helpful in this regard. From above discussion it is concluded that Husk can be used as alternative fuel of power generation in Bangladesh.

REFERENCES

[1] “Generation Planning BPDB”, Accessed at September 2014, available at http://www.bpdb.gov.bd/bpdb/index.php?o ption=com_content&view=article&id=12&Itemid=126.

[2] MR.Giddel and AP.Jivan, “Waste to Wealth, Potential of Rice Husk in India an India a Literature Review”. International Conference on Cleaner Technologies and Environmental Management PEC,Pondicherry, India. January 4-6,2007.

[3] “Rice Knowledge Bank”, Accessed at October 2014, available at http://www.knowledgebank.irri.org/rkb/ricemilling/

byproducts-and-their-utilization/rice-husk.html

[4] “Bioenergy Consult”, Accessed at April 2014, available at http://www.bioenergyconsult.com/tag/rice-husk/

[5] Jeng-Chyan. M.Lin, “Combination of a Biomass Fired Updraft Gasifier and a Sterling Engine for Power Production”, Journal of Energy Resources Technology, Volume 129, Issue 1, March, 2007.

[6]Report on “Survey of Major Rice Mill Clusters of Rajshahi Division”, German Development Cooperation (GTZ), Bangladesh,- Ahiduzzaman, Baqui, Mahmud, Khair.

International Conference on Materials, Electronics & Information Engineering, ICMEIE-2015 05-06 June, 2015, Faculty of Engineering, University of Rajshahi, Bangladesh

www.ru.ac.bd/icmeie2015/proceedings/

ISBN 978-984-33-8940-4