Summary  : Technologies for better utilization of Rice Husk as source of Energy in rural areas are detailed in this report.

Year of Publication : 1993

Table Of Contents : 

Executive Summary Introduction

Research design & methodology

Present status of technologies for use of rice husk as energy source and technological development

India & abroad

Selected sub-set of technologies and technology assessment

Techno-Market Survey findings

Technological options for India

Preferred Options suggested action plan

Techno-Market survey on Technologies for use of rice husk as source of energy in rural area

1.1 With the fast depletion of non-renewable sources of energy i.e. coal, oil, etc. the importance and relevance of biomass which is a renewable resource of energy is increasing day by day.

1.2 Rice husk is a by product of rice milling. It constitutes about 20% of paddy by weight, has a calorific value of about 3500 k cal /kg., low bulk density of 110 kg/m3, ash content of 16.5% and high silica content of 15%.

1.3 In India approx. 110 million tonnes of paddy is produced annually, yielding about 20 mt. of rice husk. If utilized as fuel, this can replace about 10 mt of coal or about 5 mt of oil. Major rice producing states include West Bengal, Uttar Pradesh, Andhra Pradesh, Bihar and Punjab.

1.4 Techno-Market Survey – Objectives

The techno-market survey report on Technologies for use of Rice Husk as Energy Source in Rural Areas covers the following:

The relationship and importance of selected subset of technology (gasification, briquetting etc.) to the broad one to which it belongs (Energy: Rice husk)Assessment of technologies and options available to India.

Assessment of associated environmental pollution, Socio-economic aspects of technologies.The economic aspects of technologies their feasibility and preferred options.Forecast and impact of preferred options, linkages to broad area of technology and spin-off.Suggested action plan for promotion and greater dissemination of technologies in rural areas and identification of relevant agencies. Individuals etc.

1.5 Techno-Market Survey – Methodology

i) Desk Research

An initial desk research was done through published sources, government sources (DNES), organizations (TERI etc.). to gather information on biomass programme of Government of India, major rice husk generation states and sources (modern mills, hullers, shellers etc), present utilization of rice husk for energy related applications ( India & Abroad), major technology/equipment suppliers (India & Abroad), R&D Organizations, Association etc.

ii) Field Survey

A detailed field survey was conducted with the help of pre-tested structured questionnaire; contacts were included R&D organizations, equipment manufacturers, experts, government departments, etc.

iii) Mail Survey

Indian organizations who could not be contacted personally and foreign organizations, were contact through mail survey with the help of structured questionnaires.

iv) Total Contacts

In all about 33 Indian organizations and 21 foreign organizations were contacted.

v) Report Preparation

The information/ data obtained through desk research, field contacts, mail survey was collected, edited and analyzed. Since thrust is on rural area’s technological options, which were economically feasible and offered other advantages like ease of maintenance, easy to replicate, generation of gainful employment, improvement of standards of living in rural areas, were given preference for determination of preferred options. 

1.6 Techno-Market Survey Findings

India

i) For energy related applications, rice husk is being utilized as a fuel for various applications i.e.

* As a fuel in rice mill furnaces, especially in mills producing parboiled rice, energy is utilized for Steam/Hot water and hot air for dying. Inclined step grate type rice husk furnaces are in use

at majority of installations although high efficiency cyclone/ suspension furnaces are being designed & developed. This is the largest single source of rice husk consumption for energy. * As a fuel in boilers for steam generation in rural based industries, generally Lancashir type boilers are in use, although trend is towards fluidized bed combustion boilers. This constitutes the second largest application of rice husk for energy. * As a fuel in rice husk gasifier, for generation of producer gas used for various applications such as electricity generation, running of diesel pumpsets, furnaces etc. Down draft design of rice husk gasifier are popular. * As a fuel in brick kilns, domestic stoves in rural areas.

ii) In India paddy is milled at various levels i.e. hand pounding, small hullers, shellers, modern rice mills. Modern rice mills account for about 55% of paddy processed.

iii) The husk price varied from Rs. 300 -Rs. 800/t and is high in industrialized states/regions. The average husk price would be around Rs. 400/t.

iv) Major non-energy applications of rice husk include animal feed, filling of low lying lands, particle boards/chemical manufacture.

v) Rice mills producing parboiled rice utilize 40-45% of husk generated at mill itself for energy whereas mills producing raw rice sell 100% of rice husk generated. Approximately 50%of total rice produced in India is consumed as parboiled rice.

vi) Major R&D Organizations/institutes/private organizations working in the field of development and commercialization of rice husk energy utilization systems include:

A) Energy Efficient Furnaces* Punjab Agricultural University, Ludhiana* IIT, Kharagpur

B) Gasifiers* Grain Processing, Calcutta* Punjab Agricultural University, Ludhiana* Associated Engineering Works, A.P.* IIT, Bombay* IIT, Delhi

C) Briquetting Machines* Solar Sciences Consultancy (P) Ltd., New Delhi * School of Applied Research, Sangli* NRDC, New Delhi.

D) Stoves* IIT, Delhi* IISc, Bangalore* Central Fuel Research Institute, Dhanbad

E) Utilization of Ash (Cementitious Materials)* Central Building Research Institute, Roorkee* IIT, Kharagpur

F) Fluidized Bed Combustion Boilers* Thermax, Pune* Cethar Vessels Ltd., Delhi* Since rice husk is utilized for various applications (mills, non-energy related applications, boilers, kilns, etc.) it is estimated that out of 20 mt of husk generated per annum about 40% i.e. 8 million tonnes would be available for energy related uses in rural areas.

Abroad

vii) Total Production of rice in the world during 1989 was estimated at 473 mt. generating about 140 mt. of husk. China is the world leader with about 37% share.

viii) The utilization pattern of rice husk differs from country to country but major end uses include fuel for rice mill furnace boilers, stoves, gasifiers etc. and briquetting. Countries in which rice husk is being utilized on large scale include China, Philippines, Thailand, Japan Italy Brazil, Korea, etc.

ix) China is the world leader in rice husk gasification technology, open more (throat less, topless) down draft gasifiers of capacity 60 kW/160 kW have been commercialistic. More than 100 rice husk gasifiers are working at present in China, basically for electricity generation at rice mills. Other major countries where rice husk gasifiers have been developed include Thailand, Philippines, Japan, Indonesia, USA.

x) Rice husk stoves are being used in Indonesia, Thailand, Philippines. Three types of stoves are being manufactured i.e. packed, natural draft and smouldering.

xi) Rice husk briquetting machines have been designed and commercialized in Japan, Switzerland, Thailand, USA etc. Briquetting machine based on ‘Fred Hausmann’ design are popular.

1.7 Preferred Options for India

The preferred options in India for effective utilization of rice husk for energy in rural areas include:

i. Electricity generation from medium capacity rice husk gasifiers (50 kW capacity systems) specially in isolated villages where electricity from grid is not available.

ii. Installation of rice husk based stirling engines/small gasifiers pumpsets (5 HP capacity), for irrigation purposes.

iii. Promotion of rice husk briquetting units as a rural industry especially in industrialized rural areas where these briquettes could be used as fuel in boilers, brick kilns etc.

iv. Installation of rice husk stoves in place of stoves utilizing wood /dung cakes as fuel, since these stoves have higher thermal efficiency and result in smokeless cooking.

A) Electricity Generation form Rice Husk Gasifiers

ForecastThe electricity generation potential from rice husk gasifiers in rural areas is estimated as:

Year Electricity Potential (MW)1992-93 51995-96 281999-2000 84

Impact The annual savings of diesel oil by preferring rice husk gasifiers over diesel gensets for electricity generation in rural areas is estimated at:

Year Savings-Diesel Oil (Rs. Crores)1992-93 31995-96 16.51999-2000 52

* Cost of electricity generation in rice husk gasifiers systems is low by about 4% when compared to diesel gensets. * Greater assurance of electricity in remote rural areas.* Employment generation to be extent of 18 persons (directly & indirectly) per 50 MW capacity gasifiers system.* Cottage industries could also be promoted based on useful gasifier system by products (tar & cinder)< for rural upliftment. * Better impact on environment by power air pollution when compared to diesel gensets which run on 100% diesel.

B) Stirling Engines for Irrigation

ForecastEstimated potential for installation of rice husk based stirling engines (5 HP capacity) in rural areas is:

Year Stirling Engines (Thousand Nos)1992-93 6.51995-96 401999-2000 142

Impact Estimated saving of diesel by replacing diesel pump sets by Stirling Engines:

Year Diesel Saving (Rs. Crores)1992-93 71995-96 421999-2000 18

* Better impact on environment, lower pollution when compared to diesel pump sets.* Reliable sources of irrigation in recent areas.

C) Rice Husk Briquetting

ForecastPotential for promotion of rice husk briquetting plants (500 kg/h capacity) are estimated as:

Year Briquetting Plants (Nos)1992-93 401995-96 551999-2000 100

Impact Savings of coal if rice husk briquettes are used as alternate fuel are estimated as:

Year Coal Saving (Rs. Crores)1992-93 141995-96 661999-2000 160

* Rice husk briquettes are economical by about 20% compared to coal. * Lower pollution while briquette burning due to low ash, sulphur content compared to coal. * Generation of employment in rural areas, is to the extent of 40 persons (directly & indirectly) per 500 kg/h capacity briquetting plant.* Easy storage, handling transportation of rise husk briquettes, higher combustion efficiency and sustained high intensity burning compared to loose husk.

D) Rice Husk Stoves

ForecastPotential for installation of rice husk stoves in rural areas is estimated as below:

Year Rice husk Stoves (Lacs Nos)1992-93 11995-96 1.31999-2000 2.2

Impact Saving of wood by substituting rice husk stoves is estimated as:

Year Firewood Saving (Rs. Crores)

1992-93 91995-96 451999-2000 115

* Smokeless cooking, thus eliminates eye and lung diseases caused due to smoke among women in rural areas. * Better hygiene and environment in rural areas. * Stoves are simple in design, and could be fabricated at village level, creating additional employment opportunities. * Rice husk stoves are about 10% more economical compared to improver wood stoves, and provide economical cooking.

E) The anticipated availability ad utilization of rice husk in preferred options for various years are summarized below:

Year Rice husk    

  Availability (Lac t) Utilization (Lac t) % Utilization

1992-93 81 4.5 5.5

1995-96 85 20.5 24

1999-2000 91 68 75

1.8 Suggested Action Plan

i. In order to promote rice husk utilization technologies for energy, greater awareness will have to be created in rural areas regarding their advantages vis-avis other options.

ii. Promotion and demonstration of feasible rice husk energy utilization technologies in rural areas, could be achieved through rural exhibition/melas, T.V. Programmes, establishment of technology demonstration centers etc. DNES, NRDC etc. can play a vital role in technology promotion.

iii. The commercialization of technologies developed by R&D institutions is on a low scale, which could be enhanced by greater interaction between technology development organizations and manufacturers/fabricators of equipment. Commercialization of technologies would lead to greater propagation of technologies. DNES, NRDC, R & D institutions, private entrepreneurs can contribute in this report.

iv. High cost of technologies / equipments has been one of the major hindrance in wide scale adoption of technologies in rural areas. It is recommended that low cost technologies/equipment should be developed by R & D institutions by way of usage of cheaper materials, design improvement etc.

v. It is recommended that capital subsidy of 30-40% should be provided on biomass briquetting equipments as briquettes are renewable form of energy and helps in conservation of coal, in line with government policy of providing subsidies to biomass gasifiers, stoves, etc.

vi. A few R & D areas identified with respect to rice husk energy utilization technologies of energy.

vii. Development of special alloy dyes for briquetting machines which can withstand highly abrasive nature of husk.

viii. Development & commercialization of technologies which utilize maximum rice husk energy and also generate useful by products i.e. white ash out of which other useful products like amorphous silica could be extracted. Organizations such as IIT-Delhi. IIT-Bombay; DAV, Ludhiana (gasifiers), SAR, Samgli; Solar Sciences Consultancy Pvt. Ltd. Delhi (briquetting machines). CFRI-Dhanbad; IISc-Bangalore (Stoves), CBRI-Roorkee, IIT-Kharagpur (Ash Utilization) can contribute in R&D activities development.

ix. Rice husk gasifier based electricity generation systems (50kW capacity) are ideal for isolated rural areas. Since cost of these systems is high (50 kW system costs Rs. 7 lacs), these could be promoted by State Governments / State Electricity Boards. North Eastern States such as Assam, Arunachal Pradesh, Manipur, etc. offer lot of potential for such systems. These systems would lead to lots of benefits like employment generation, diesel oil savings etc.

x. Rice husk briquetting units would be a viable option for industrialized rural areas where briquettes could be used as boiler fuel in place of coal. Entrepreneurs could be encouraged by State Financial Institutions, State Industrial Development Corporations, District Industrial Centers etc., to establish such units in rural areas thereby generating employment. Loans on liberal terms could also be provided by financial institutions.

xi. Stirling engines (5 HP) can be promoted for irrigation in place of diesel pump sets. High cost of stirling Engine could be brought down by mass production of these engines.

xii. Rice husk stoves are much more energy efficient than improved wood stoves and lead to smokeless cooking, reduces deforestation. Such systems could be promoted on a larger scale under ‘National Programme on Improved Chulhas’ by DNES. These systems can be fabricated at village level.

xiii. Maximum co-operation is required between Nodal Agency (DNES). Voluntary Organizations, technology/equipment suppliers, village Panchayats etc. for greater promotion and dissemination of technologies in rural areas.

xiv. Training is very essential for effective dissemination of technologies, and can be imparted to rural youth/people in technology demonstration cum training centers by representatives of technology/equipments suppliers.

xv. International cooperation between leading foreign countries, i.e. China, Philippines, Thailand etc. and India is very essential in this field, for development of rice husk utilitarian technologies, updating of technologies based on experiences, technology transfer etc. International Organizations such as FAO, UNIDO, UNDP etc. can promote greater international cooperation.

xvi. It is recommended that further in-depth studies should be initiated to identify appropriate rice husk energy utilization technologies for major regions (region wise) since feasibility of

various identified technologies would vary from place to place, state to state and would depend on a number of factors, like husk prices, extent of industrialization in area, husk generation source in area etc.