PRODUCER GAS STOVE (The materials utilized in the construction of the stove are locally available and cheap)

                                                                 CHAPTER ONE

INTRODUCTION

          Most of the rural Indian families depend heavily on biomass to meet their household cooking energy requirements. Fuel wood often accounts for a major fraction of the total biomass use. Fuel wood is generally preferred to non-wood biomass residues due to its higher energy density and convenience in use and transportation. Large quantities of biomass residues are available in India. These include rice husk, rice straw, wheat straw, corncob, coconut shell, bagasse, and many other agricultural residues. The residues are normally difficult to use, particularly in small-scale systems, due to their uneven and troublesome characteristics. Although biomass offers itself as a sustainable and carbon-neutral source of energy, its inefficient use in household cooking results in wastage, indoor air pollution and related respiratory and other health problems. Excessive use of fuel wood is also exerting pressure on the region’s forest cover. Although large quantities of surplus biomass residues are available in India, due to certain difficulties experienced in using them in the traditional cooking devices, their use has been severely restricted. The non-availability of suitable cost-effective technologies for utilizing biomass residues for household cooking has resulted in gross under utilization and neglect of biomass residues as a potential energy source in this sector.

         However, energy from biomass can be efficiently used by means of gasifier stoves. Many different types of gasifier stoves have been designed and constructed so far and they are showing good performance too.

Wood gas cook stove developed by Thomas Reed and Ron Larson[1], Charcoal making wood gas cook stove developed by Elsen Carstad[2], IISc gasifier stove by Indian Institute Of Science[3], San San rice husk gasifier stove developed by U Tin Win[4] and many others have led to an efficient harnessing of biomass energy.

Gasification is the process that converts carbonaceous materials such as coal, petroleum, biofuel, or biomass into carbon monoxide and hydrogen by reacting the raw materials, such as house waste, or compost at high temperatures with a controlled amount of oxygen and/or steam. The resulting gas mixture is called synthesis gas or syngas and is itself a fuel. Gasification is a method for extraction of energy from many different types of organic materials.

Pyrolysis is a form of incineration that chemically decomposes organic materials by heat in the absence of oxygen. Pyrolysis typically occurs under pressure and at operating temperatures above 430 °C (800 °F). In practice, it is not possible to achieve a completely oxygen-free atmosphere. As some oxygen is present in any pyrolysis system, a small amount of oxidation occurs. The word is coined from the Greek- derived elements, pyre meaning “fire” and lysis meaning “loosening”.

1.1 Biomass as an energy source for cooking in Asia:

Domestic cooking accounts for the major share of the total biomass use for energy in Asia. However, use of biomass fuels in traditional stoves is characterised by low efficiency and emission of pollutants. In an effort to address these problems, many of the Asian countries have initiated national programs to promote improved cook stoves. Although significant achievements have been reported in some of these countries, the potential for further efficiency improvements is still very large. A study by Bhattacharya et al[7] estimated that the biomass saving potential in seven Asian countries (China, India, Pakistan, Nepal, Philippines, Sri Lanka and Vietnam) as 152 million tons of fuel wood and 101 million tons of agricultural residues, in the domestic cooking sector alone in early nineties. The amount of biomass that can be saved through efficiency improvement can serve as a source of additional energy and can potentially substitute for fossil fuels to reduce net GHG emission. With the escalating costs of fossil fuels and gas as a preferred cooking fuel (than fuel wood, residues, kerosene etc.), biomass gasifiers are attracting renewed interest. The possibilities for biomass gasification technology for cooking applications are leading to a number of initiatives to demonstrate the potential benefits of introducing them in developing countries. Wider use of the gasifiers stoves in developing countries could save on cooking fuel costs, improve the reliability of fuel supply by making rural communities more self-reliant and improve indoor air quality. Gasifier-based cooking systems have some very attractive features, i.e., high efficiency, smoke free clean combustion, uniform and steady flame, ease of flame control, and possible attention-free operation over extended duration. While these make them an attractive choice in the kitchens of the developing world, there are cost and technology barriers which limit their wider adoption.

1.2 Difference between gasifier stoves and conventional stoves:

Apart from being fuel efficient, gasifier stoves are also emission efficient in comparison to traditional cook stoves. The traditional cook stoves, because of their very low efficiency, emit more than 10% of their carbon as products of incomplete combustion (PIC) comprising varying amount of tars. In addition, about 100-180 g of carbon monoxide and 7.7 g of particulate matter are also emitted per kg of wood. Gases such as methane, total non-methane organic compounds (TNMOC) and N₂ O are added to this. These PIC emissions are even higher in the case of loose biomass or cow dung used as fuel in these stoves. Some of the natural draft stoves (based on combustion of gas produced from biomass) developed so far are listed in Table 1. The capacity of these stoves ranges from 3kWth to 20kWth, making them suitable for domestic as well as community cooking applications. Compared to the 5-15% efficiency of traditional cook stoves in the Asian region, the efficiency of these gasifier stoves is in the range of 25-35%. 

1.3 History:

The gasification process was originally developed in the 1800s to produce town gas for lighting and cooking. Electricity and natural gas later replaced town gas for these applications, but the gasification process has been utilized for the production of synthetic chemicals and fuels since the 1920s. Wood gas generators, called Gasogene or Gazogène, were used to power motor vehicles in Europe during World War II fuel shortages.

Four types of gasifier are currently available for commercial use:

1.3.1. The counter-current fixed bed ("up draft") gasifier: It consists of a fixed bed of carbonaceous fuel (e.g. coal or biomass) through which the "gasification agent" (steam, oxygen and/or air) flows in counter-current configuration. The ash is either removed dry or as a slag. The slagging gasifiers have a lower ratio of steam to carbon  , achieving temperatures higher than the ash fusion temperature. The nature of the gasifier means that the fuel must have high mechanical strength and must ideally be non-caking so that it will form a permeable bed, although recent developments have reduced these restrictions to some extent. The throughput for this type of gasifier is relatively low. Thermal efficiency is high as the gas exit temperatures are relatively low. However, this means that tar and methane production is significant at typical operation temperatures, so product gas must be extensively cleaned before use. The tar can be recycled to the reactor.

1.3.2. The co-current fixed bed ("down draft") gasifier: It is similar to the counter-current type, but the gasification agent gas flows in co-current configuration with the fuel (downwards, hence the name "down draft gasifier"). Heat needs to be added to the upper part of the bed, either by combusting small amounts of the fuel or from external heat sources. The produced gas leaves the gasifier at a high temperature, and most of this heat is often transferred to the gasification agent added in the top of the bed, resulting in energy efficiency on level with the counter-current type. Since all tars must pass through a hot bed of char in this configuration, tar levels are much lower than the counter-current type.

1.3.3. The fluidized bed reactor: Here, the fuel is fluidized in oxygen and steam or air. The ash is removed dry or as heavy agglomerates that defluidize. The temperatures are relatively low in dry ash gasifiers, so the fuel must be highly reactive; low-grade coals are particularly suitable. The agglomerating gasifiers have slightly higher temperatures, and are suitable for higher rank coals. Fuel throughput is higher than for the fixed bed, but not as high as for the entrained flow gasifier. The conversion efficiency can be rather low due to elutriation of carbonaceous material. Recycle or subsequent combustion of solids can be used to increase conversion. Fluidized bed gasifiers are most useful for fuels that form highly corrosive ash that would damage the walls of slagging gasifiers. Biomass fuels generally contain high levels of corrosive ash.

1.3.4. The entrained flow gasifier: Here, a dry pulverized solid, an atomized liquid fuel or a fuel slurry is gasified with oxygen (much less frequent: air) in co-current flow. The gasification reactions take place in a dense cloud of very fine particles. Most coals are suitable for this type of gasifier because of the high operating temperatures and because the coal particles are well separated from one another. The high temperatures and pressures also mean that a higher throughput can be achieved; however thermal efficiency is somewhat lower as the gas must be cooled before it can be cleaned with existing technology. The high temperatures also mean that tar and methane are not present in the product gas; however the oxygen requirement is higher than for the other types of gasifiers. All entrained flow gasifiers remove the major part of the ash as a slag as the operating temperature is well above the ash fusion temperature. A smaller fraction of the ash is produced either as a very fine dry fly ash or as a black colored fly ash slurry. Some fuels, in particular certain types of biomasses, can form slag that is corrosive for ceramic inner walls that serve to protect the gasifier outer wall. However some entrained bed type of gasifiers do not possess a ceramic inner wall but have an inner water or steam cooled wall covered with partially solidified slag. These types of gasifiers do not suffer from corrosive slags. Some fuels have ashes with very high ash fusion temperatures. In this case mostly limestone is mixed with the fuel prior to gasification. Addition of a little limestone will usually suffice for the lowering the fusion temperatures. The fuel particles must be much smaller than for other types of gasifiers. This means the fuel must be pulverized, which requires somewhat more energy than for the other types of gasifiers.

1.4. Natural vs Forced convection

1.4.1. Natural convection: provides poor mixing of air with fuel gases and can result in incomplete combustion, soot and emissions in open wood stoves. A chimney can supply 1 mm water pressure per meter of height. Addition of a chimney for cooking can greatly improve wood combustion in closed models, but also adds complication and requires wasting heat to operate[7].

1.4.2. Forced convection: provides good mixing and combustion for gas cooking and is widely used in homes and camping stoves. The 3 W blower used in the Turbo Stove provides 7.5 mm water pressure and makes clean cooking possible[7].

                                                               CHAPTER TWO

OBJECTIVE AND SCOPE

2.1. Objective of the work

The basic aim of the project is to design a gas stove working on biomass energy for domestic use that is cheaper, cleaner and more efficient than the conventional cooking methods used in rural areas. Therefore the objectives of our work are:

2.1.1. To design a gasifier stove for domestic purpose.

2.1.2. To construct the stove using locally available materials.

2.1.3. To carries out experimentations to evaluate the performance of the stove.

2.2. Scope

    2.2.1. Study of existing designs of producer gas stoves.

    2.2.2. Carry out comparison of different existing designs.

    2.2.3. Selection of a particular design and carry out study for modifications of the design      to fit into our local conditions.

    2.2.4. Selection of locally available cheap materials for practical implementation of the        design.

   2.2.5. Construction of the designed gas stove.

   2.2.6. Experimentation to evaluate efficiency of the stove.

 CHAPTER THREE

METHODOLOGY

3.1. Chemistry of Gasification

In a gasifier, the carbonaceous material undergoes several different processes:

1. The pyrolysis (or de-volatilization) process occurs as the carbonaceous particle heats up. Volatiles are released and char is produced, resulting in up to 70% weight loss for coal. The process is

Figure 3.1: Pyrolysis of carbonaceous fuel

                                                         Figure 3.2: Gasification of char

  

dependent on the properties of the carbonaceous material and determines the structure and composition of the char, which will then undergo gasification reactions.

2. The combustion process occurs as the volatile products and some of the char reacts with oxygen to form carbon dioxide and carbon monoxide, which provides heat for the subsequent gasification reactions. Letting C represent a carbon-containing organic compound, the basic reaction here is        

                                                            C + 1/2O₂ = CO₂

3. The gasification process occurs as the char reacts with carbon dioxide and steam to produce carbon monoxide and hydrogen, via the reaction,

                                                          C + H₂O = H₂ + CO

4.  In addition, the reversible gas phase water gas shift reaction reaches equilibrium very fast at the temperatures in a gasifier. This balances the concentrations of carbon monoxide, steam, carbon dioxide and hydrogen.          

                                                         H₂O + CO = CO₂ + H₂

              In essence, a limited amount of oxygen or air is introduced into the reactor to allow some of the organic material to be "burned" to produce carbon monoxide and energy, which drives a second reaction that converts further organic material to hydrogen and additional carbon dioxide. Further reactions occur when the formed carbon monoxide and residual water from the organic material react to form methane and excess carbon dioxide. This third reaction occurs more abundantly in reactors that increase the residence time of the reactive gases and organic materials, as well as heat and pressure. Catalysts are used in more sophisticated reactors to improve reaction rates, thus moving the system closer to the reaction equilibrium for a fixed residence time.

            Gasifier-based cooking systems have some very attractive features, i.e., high efficiency, smoke free clean combustion, uniform and steady flame, ease of flame control, and possible attention-free operation over extended duration. While these make them an attractive choice in the kitchens of the developing world, there are cost and technology barriers which limit their wider adoption.

3.2. Safety Measures to follow:

          Producer gas was the only gas fuel widely available until 1940 when natural gas pipelines became common. Since producer gas contains 10-30% CO, it is a real health hazard if the flame is extinguished or incomplete combustion occurs [8]. (Smoky open fires and insufficient cooking fuel are also major health hazards in the world today.) Therefore it is necessary to mandate good practice in using the Producer Gas Stove. In the volatile combustion mode CO is a minor hazard because if the flame should go out, the copious smoke warns the operator to re-ignite the fire or move the stove outside. However, in the charcoal combustion mode the CO is odorless and could pose a health hazard. It is recommended that all stoves including the Producer Gas Stove should be operated under a hood carrying the cooking odors and possible stove emissions to the outside by natural or forced convection. That is the practice in most kitchens in developing countries today and should be followed as the rest of the world develops.

3.3. Producer Gas Stove Emissions:

       Producer-gas cooking has very low emissions and can be operated indoors with proper precautions once established [9]. However, if the fire is extinguished for any reason the production of smoke and CO continues, so that it is important to be able to extinguish it completely or take

it outside. The stove is difficult to extinguish but can be done by closing the primary air supply at the bottom and outer cylinder side. During gasification of wood, if the fire is extinguished the acrid tars in the wood make it unlikely that one would breathe too much CO. However, after the wood is gasified the stove contains hot charcoal and so can be a major source of CO. For this reason it is important to either continue to burn the charcoal or to cut off all air to the stove.

3.4. Study of existing stoves and search for a suitable design:

i.                 The Wood-Gas Cook Stove of Reed and Larson use small wood chips and sticks for operation, and produce very low CO emission, and hence suitable for indoor cooking. The rate of gas production can be controlled by controlling the primary air supply to the gasifier. The gasifier produces charcoal as a by-product [1].

                                    Figure 3.3: Wood-Gas Cook Stove developed by Reed and Larson

ii.              Elsen Karstad’s Charcoal Making Wood Gas Cooking Stove is a simple stove developed for the East    African households [2].

                         Figure 3.4: Elsen Karstad's Charcoal Making Wood-Gas Cook Stove

iii.            The Holey Briquette Gasifier Stove developed by Stanley and Venter (2003) operates using a single biomass briquette with a central hole (typically produced in extrusion type briquetting machines) placed in the middle of the combustion/gasification chamber. At about 1.1 kW power, the stove offers efficiency of up to 35%[5].

PROTOTYPE OF BRIQUETTE GASIFYING STOVE

Figure 3.5: Holey Briquette Gasifier Stove developed by Stanley and Venter

(1.1kW power; 35% efficiency).

iv.       The IISc Gasifier Stove can be operated using small wood sticks and pelletised waste, and has a thermal output of 3-4 kW. Offering a water-boiling efficiency of 25-35%, the stove can operate continuously for about 2 hours for a single fuel loading. Emission from the stove has been found to be low[3] .

Figure 3.6: IISc’s Gasifier Stove

v.            The San San Rice husk Gasifier Stove developed in Myanmar offers smokeless combustion ofrice husk in an efficient manner. Gasification can be improved by mixing kitchen wastes suchas potato peels, green leaves and fresh biomass, chopped into half inch pieces, with the rice husk[4].

Figure 3.7: San San rice husk gasifier stove developed in Myanmar

vi.             The three models of gasifier stoves developed at AIT (Institutional Gasifier Stove/IGS2, Domestic Gasifier Stove/DGS2 and Commercial Gasifier Stove/CGS3) operate on cross-draft principle, using wood chips, wood twigs, coconut shells and ricehusk/sawdust briquettes as fuel (Figures 6 and 7). Water-boiling efficiency is in the range of 22-31%, depending on the type of stove and fuel used. Combustion is clean and steady, and no tending is generally required during operation[6].

Figure 3.8: Institutional Gasifier Stove IGS2                    Figure 3.9: Commercial Gasifier Stove CGS3

                    developed at AIT                                                                           developed at AIT

(5.5 kW; 29% efficiency with woodchips)                                              (11.5 kW; 31% efficiency with woodchips)

vii.   Wood gas stove developed by College of Engineering and Technology, Maharana Pratap University of Agriculture and Technology, Udaipur, Rajasthan India, which has a capacity of 5 kw and works on natural draft gasification mode[7].

Figure 3.10: Wood gas stove.

3.5. Methodology of production of our design:

       Modification of presently available stoves

We have designed a producer gas stove working on natural draft + inverted downdraft gasification mode. For our design we took references from the following natural draft gasifier stoves developed.

        i.            Primary air mechanism: primary air is the air which is utilized in the initial burning of the biomass fed to the stove. Instead of providing separate inlets for air and fuel feed, we have used a sliding door for both entry of primary air as well as feeding biomass. Amount of air can be controlled by sliding the door.

      ii.            Ash removal mechanism: a separate hollow cylindrical shell is fitted at the bottom of the stove. The ash produced due to the burning of biomass falls from the grate and gets collected in this shell. The shell can be removed to discard the wastes and then refitted to the stove easily for use again.

    iii.            Secondary air control: this is the air which helps in the proper burning of the producer gas generated in the stove thereby producing the flame. Minute holes along the periphery of the top part of the cylinder are provided for the purpose.

    iv.            Producer gas outlet: very small holes, about seven to eight in number, are provided at the top of the small cylinder over the main reactor of the stove for the producer gas to come out and get burned to produce the flame.

      v.            Calculation of critical radius of insulation: This is calculated with the knowledge of thermal conductivity of fire clay brick(k), the convective heat transfer coefficient between air and fire clay brick(h) and finally applying the formula to calculate critical radius of insulation(r_c); which is, r_c=k/h. Now the radius of insulation provided in the stove must be greater than the critical value so as to minimize heat loss to the surrounding. By Studying all the above stoves we have designed a producer gas stove which works on the natural draft gasification mode and the design is prepared considering the availability of the materials.

r_c = 1/8 = .125m = 12.5cm

where, k = 1W/mK , h = 8W/m²K

            By Studying all the above stoves we have designed a producer gas stove which works on the natural draft gasification mode and the design is prepared considering the availability of materials and fuels in rural areas.

Figure 3.11: Solid works design of the producer gas stove.

3.6. Construction:

·         Construction of the  stove have been done using locally available materials which are listed below

Serial No.	Part of stove	Material used
1. 2. 3. 4. 5. 6. 7. 8.	Reactor Core Grate Insulation Reactor outer cover Biomass feeding door cum primary air inlet Removable portion at the bottom Upper portion for combustion of the producer gas Tripod stand	Galvanized Steel  Galvanized Steel  Normal Crushed Brick  Galvanized Steel Galvanized Steel  Galvanized Steel Galvanized Steel Mild Steel flattened bar

Table 3.1

The whole unit has been constructed in our college workshop. The various shop we used for construction are Fitting shop, Welding Shop, Carpentry Shop, Blacksmith Shop etc.

3.6.1. Construction Procedure:

·         Construction of the Reactor Core: A hollow galvanized steel cylinder of  diameter 21cm, height 44cm having a grate inside and a feed door on the body forms the main reactor core inside which pyrolysis leading to the formation of producer gas takes place. 

Figure 3.12: Reactor core

·         a)   Construction of the Grate: it is made by cutting a number of longitudinal slots on a galvanized steel plate having diameter same as that of the internal diameter of the reactor core. It is then welded at a suitable height above the bottom of the core.

Figure 3.13: Grate

·       b)   Cutting primary air inlet cum fuel feeding door on the reactor core the door dimensions (8×12cm) are first marked on the body of the core on the outside and carefully cut out using a chisel and hammer.

Figure 3.14: Primary Inlet

·         d) Preparation of insulating material: A stainless steel sheet having lap joint surrounds the core. The space between the core and the stainless steel cylinder is filled completely with crushed normal brick which acts as a very good insulating material.

·         e) Construction of Reactor Outer Cover: A stainless steel sheet is bent in the form of a cylinder and is fixed by lap joints having a diameter of 38 cm.

Figure 3.15: Insulation cover

·         Construction of upper portion of the Reactor: A small cylinder of diameter 10.16cm of galvanized steel is welded to the top of the core and there are holes on the top sheet for the gas to come out.

Figure 3.16: Reactor upper potion

·          g) Construction of lower portion of the Reactor: a circular sheet of the same material as the core is slide fitted at the bottom for removal of ash that falls from the grate fitted above.

·       h)  The tripod stand has been constructed using MS flattened bars and it is basically for holding the pot during cooking.

·         i) Assembly: All the above mentioned parts are assembled to get the stove. Below is the Stove with different parts of it.

3.6.2. Structural Modification of the Design:

After construction of the stove, we tried to fire it by feeding dry wood and coke but due to deficiency in our design it did not work as expected. Therefore the seven semester design has been modified in the present semester by consulting our guide, and the whole modified design with its mechanisms is given below.

Figure 3.17: Modified Design

3.6.3. Construction of modified design:

1. The number of secondary inlet holes has been increased for better generation of the cooking flame.
2. The holes in the top portion of the stove have been replaced by a LPG burner for getting a uniform and intense flame.

    CHAPTER FOUR

EXPERIMENTATION

4.1. Experimental set-up and procedure

The efficiency of a stove is usually defined as the ratio of heat transferred to the cooking medium to heat supplied by fuel. The stove efficiency could be evaluated by a number of standard methods such as Constant Heat Output Method, Constant Temperature Rise Method, Constant Time Method, and [10]Water Boiling Test (Prasad and Verhaart, 1983). Of these, the Water Boiling Test appears to be most commonly used and this very test method is used in the performance evaluation of our producer gas stove as well. The test is designed as a simple method with which stoves made in different places and for different cooking applications can be compared through a standardized and replicable test.

However, the WBT also has weaknesses. In order to be applicable to many different types of stoves, the WBT is only a rough approximation of actual cooking. Therefore, the efficiency of the stove as found out by WBT will vary when the stove will be subjected to real cooking.

In a Water Boiling Test, a known quantity of water is heated on the cookstove. No lid is used to cover the vessel so that evaporated water freely escapes from the vessel. The quantity of water evaporated after complete burning of the fuel is determined. Also the quantity of fuel burnt is found out by measuring the amount of fuel left unburnt inside the reactor core.

4.1.1. Apparatus for water boiling test:

1.       A pan without lid.

2.       Thermometer for measuring the ambient and boiling

           water temperature.

3.       A balance for measuring the weight of fuel, water

          and pan.

4.1.2.      Procedure

The fuel and pan to be used in the test were separately weighed. The pan was partially filled up with water and weighed again. The initial temperature of water was recorded. The stove was ignited to initiate heating of the pan. After letting the heating process to continue for about one hour and thirty minutes the burning coal in the reactor core was put off and the process of heating was thus terminated. The unburnt fuel, i.e., unburnt wood pieces were taken out and weighed in order to find out the amount of fuel actually exhausted during the test. The temperature to which water was heated was also recorded. The calorific value of dry wood was taken from standard table.

All these values are then put in the formula shown above in order to find out the efficiency of the stove. The efficiency thus found out was the theoretical efficiency of the designed stove. However, the actual performance of the stove may vary to some extent when used for real cooking.

The efficiency of the stove is calculated by using the following formula:

where,

m_w,i = initial mass of water in the cooking vessel, kg

      =6 kg

c_p,w = specific heat of the water, kJ/kg°C

      =4.2 KJ/ kg °C

m_w,evap = mass of water evaporated, kg

          =0.3 kg

m_f = mass of fuel burned

     =0.55 kg

T_e = temperature of boiling water, °C

    = 100 °C

T_i = initial temperature of water, °C

    =29 °C

H_l = latent heat of evaporation at 100°C and 105 Pa, kJ/kg

    = 2257 KJ/kg

H_f = Calorific value of fuel, kJ/kg

     = 17400 KJ/ kg

Ƞ =

    = 25.77%

4.2.   Comparisons of the performance of different gasifier stoves:

Sl no.	Name of the stove	Efficiencies
1	Briquette gasifying stove, by Thomas Reed and Ron Larson.	35%
2	Institutional gasifier stove, AIT.	29%
3	Domestic gasifier stove, AIT.	25%
4	Commercial gasifier stove, AIT.	31%
5	San San rice husk gasifier stove, by U Tin Win.	29%
6	Charcoal making wood gas cook stove, by Elsen Carstad.	30%

Table 4.1

The efficiency of our stove is 25.77% due to availability of limited scope during construction. A better performance can be achieved from the stove by using still better and precise tool and techniques for construction of the same.

Figure 4.1: Producer gas stove in operation

Figure 4.2: Evaporation of water due to tremendous heat formation

                           CHAPTER FIVE

CONCLUSION

             We have come up with a new design which is economically viable for rural households by studying some of the existing designs. Several modifications have been made in the construction of the producer gas stove which is necessary for getting much higher performance. All the materials utilized in the construction of the stove are locally available and cheap. This type of stove has the potential to save fuel wood because it can work on a great variety of non-wood or waste-wood fuels. Improvements in household’s biomass burning stoves potentially bring three kinds of benefits, i.e. reduced fuel demand, with economic and time saving benefits to the household and increase sustainability of the natural resources base;  reduced human exposure to health damaging air pollutants; and  reduced emission of the greenhouse gases that are contributing towards global climate change.

REFERENCES

Research Papers:

[1]T. B. Reed and Ronal Larson. A wood-gas stove for developing countries. Presented at the “Developments in Thermochemical Biomass Conversion” Conference,Banff, Canada, 20-24 May, 1996.

[2]Karstad, Elsen., 1997. Elsen Karstad's Charcoal Making Wood Gas Cooking Stove (Sept 97).

http://www.ikweb.com/enuff/public_html/ELK.htm

[3] IPOBIS., 2004. Portable Wood/Biomass Stoves. Combustion, Gasification and Propulsion

Laboratory, Indian Institute of Science, Bangalore. http://cgpl.iisc.ernet.in/stv_final.pdf

[4] SSIC, 2005. San San Industrial Cooperative., Ltd., Myanmar. Accessed 20 Feb 2005.

http://www.benergyssic.com/sansanrice.htm.

[5]Stanley, Richard., and Venter, Kobus., 2003. Holey Briquette Gasifier Stove Development. Aug.2003. http://www.repp.org/discussiongroups/resources/stoves/Stanley/BriqGassstove.htm.

[6]N.L.Panwar,N.S.Rathore.Design and performance evaluation of a 5kW producer gas stove.

BIOMASS AND BIOENERGY 32 (2008)1349–1352. Published by Science Direct online on 27 May 2008.

[7]Bhattacharya SC, Attalage RA, Augustus M. Potential of biomass fuel conservation in selected Asian country. Energy Conversion and Management 2001(40):1141–62.

[8]Josef Ayoub, Eric Brunet. Performance of large portable metal woodstoves for community kitchens. Renewable Energy, Vol. 7, No. 1, pp. 71 80, 1996.Copyright © 1996 Elsevier Science Ltd.

[9]T. B. Reeda,b, E. Anselmoa and K. Kircherc1.Testing & modeling the wood-gas turbo stove. Presented at the Progresss in Thermochemical Biomass Conversion Conference, Sept.17-22, 2000, Tyrol, Austria. Collected from Google Scholar.

[10]S.C. Bhattacharya, A.H. Md. M. R. Siddique, M. Augustus Leon, H-L. Pham and C.P.Mahandari. A study on improved institutional biomass stoves.Energy Program, Asian Institute of Technology, P. O. Box 4, Klong Luang, Pathumthani, Thailand.

Websites:

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                  www.google.com/google scholar

                  www.sciencedirect.com