[Abstract]:

In our country briquetting process is carried out in the screw-press type briquetting machine on which mainly briquetting of rice husk are commercially produced. Other

alternatives are often run in commercial purpose because of various problem faced. But to become dependent on a single raw material will cause hamper when there is scarcity of that material in the market. Thus to take the full advantage of the locally available raw materials, different mixture of those are considered for producing briquetting. An experimental investigation has been conducted to evaluate the properties of different raw

materials and their products from a briquetting machine. Significant properties of the product from different mixture of raw materials with different compositions have also been determined. A screw press type briquetting machine with heated die has been used for producing briquettes. An economic analysis of the system has also been performed in this study

Ali, Md Nawsher

Islam, Md Mainul

Islam, Md Shahidul

Khan, Kamrujjaman

English

University of Southern Queensland ePrints

II /I 2003) Decem"('/'. 2003 AN INVESTIGATION ON THE RAW MATERIALS AND PRODUCTS OF THE BRIQUETTING MACHINE Md. Mainullslam t , Kamrujjaman Khan), Dr. M. N. Ali2, and Md. Shahidullslam1 ABSTRACT ILecLurer. ~Professor. JRcscarch Assistant Depurlment of Mechanical Engineering Khulna University of Engineering & Technology Khulna 9203. Bangladesh In our country briql/etti/lg process is carried out ill the screw-press type briquelling machine on which mainly briquettillg of rice husk are commercially produced. Other alternatives are often run in commercial purpose because ofvariolls problem faced. ButfO become dependent on a single raw material will cause hamper when there is scarcity of that material in [he market. Thus to take the full advantage of the locally available rail' materials, different miXlUre of those are considered for producing briqllelting. An experimental investigation has been conducted to evaluate the properties of different raw materials and their product!; from a briquetting machine. Significant properries of the produCl from different mixture ofrt/w materials witli different compositions have also been determined. A screw press type briquettillg machille with heated die has been //Sed for producing briquettes. An economic analysis of the system has also been performed ill {his study. Keywords: Briquetting, Raw materials, Rice husks, Rice straw, Bagasse and Sawdust. 1. INTRODUCTION The realization that deforestation and wood fuel shortages are likely to become pressing problems in many countries has turned attention to other type of biomass fuel. Agricultural residues are principle, one of the most important of these. They arise in large volumes and in the rural areas, which are often subjected to some of the' worst pressure of wood shortage. However, residues are often bulky and difficult to burn so various conversion techniques have been developed. One of the oldest of these is briquetting, which has been used in Europe since the 191h. century to make fuel from low-grade peat and brown coals. Biomass densification can be regarded as an established technology and machines of a wide range in terms of technique, raw materials and capacity are available. The compaction of loose combustible material for fuel making purpose was a technique used by most civilizations in the past, though the methods were no more the simple bundling, bailing or dying. The u~e of briquetting for conversion of agricultural residuc is comparatively recent, however, and has only been taken up in developing countries in lhe last ten years. The experience of briquetting agriculture residues has been mixed. Variolls technica! problems have been encountered bu't thc main difficulty has been the f,lct that in many pluee!;, briquctting are too high in cost lo complete with existing wood fuel. How in somc counLries, a briquetting industry has begun lo develop and find its market price. 3S Bioenergy technologies help to protect the environment by muking use of renewuble plant material such as saw dust, rice trimming's, rice straw, alfalfa and switch gmss, poultry litter and other animals w:astes, industrial waste and the paper component of municipal solid waste. They are used today in a variety of processes, includifJg the production of clean tmnsportation fuels, electricity and chemicals. Like most of the developing countries, biomass fuel has been considered as one·of the major sources in Bangladesh. Recently survey shows that, around 66% of the primary energy are 09w being supplied through some form of biomass energy [1]. On the other hand oil imported has been increased to 35% in the last ten years [2]. Thus the unpredictable price and dwindling supply of fuel oil impose a serious limitation on the contest of socio-economic demand. However unplanned and crude use of biomass energy affected the ecology and environment. It aggravate deforestation, environment pollution and similar other problems. Specially, crude combustion of biomass residues have a huge amount of Nitrogen oxides in this context, using improved form of biomass residue and their efficient combustion is only potential solution. There are seveml techniques available to use biomass fuel'properly. Briquetting, torification, gasification are some of the proper means of biomass energy utilization. Briquetting is a procedure of compacting residue into higher bulk density and regular shape. This eliminmes the difficulties of using raw biomass foe domestic cooking and other industrial sectors become increasingly popular. There are several ways for producing briquettes. One of the popular methods is compacting biomass residue in a heated -die-screw type briquetting machine. Nowaday more than 200 similar type of small briquetting plants are in operation in Bangladesh [31. They are mostly centered in the north and south sides of the country since these areas are not including in the national natural gas network. However the technical as weI! as economical bases of plants are in pri vate stage. This is because, the technology used for biomass briquetting machine manufacturing is not well developed in Bangladesh. Most of the plants are poor copy of imported machines, which are failed to meet the proper demand of biomass densification technique. As a result, the plant has higher energy consumption, low production and severe maintenance problem, which basically lead to lower turnover and ultimately leave the whole prospect - briquetting techniques in risk. In this study an experimental investigation has been conducted to evaluate the properties of different raw materials and their products from briquetting machine. Significant properties of the product from different mixture of raw materials with different compositions· have also been determined. A screw press type briquetting- machine y,rith a heated die ha.s been used for producing briquettes. An economic analysis o( the system has also been performed. 2. PROPERTIES OF RAW MATERIALS AND PRODUCTS 2.1 Properties of Raw Materials Moisture Contents: There are two ways exist to report moisture content (MC) of biomass materials such as wet ,basis and dry basis. MC on wet basis is the amount of moisture in the biomass expressed as a percentage of total weight of wet biomass and dry basis is the amount of moisture expressed as percentage weight of moisture of free biomass. After measuring the stabilized mass, the sample is heated to reaches a constant mass, until the difference between two successive measurements is not more thun 0%. Then sample is allowed to cost and weighted to determine its anhydrous mass. 36 Bulk Density: It is the ratio of mass volume of the material. Bulk density depends on density of each fragment of materials. This mass is measured using a balance of weighting to an accuracy of 0.1 % of the mass to be measured. Calorific Value: It is the quantity of heat released by complete combustion of a unit quantity of material. The method used is Bethlot - Mahler method. A known mass of materials the moisture content of which has been determined is burnt in the presence of oxygen ~:. high pressure in a bomb calorimeter contained in a'completely insulated receptacle. Since, operation is adiabatic; the temperature rise is directly proportional to the calorific value. Most calorimeter measures the higher calorific value (HCV) which is determined after complete condensation of water vapour contained in the combustion gas. The lower calorific value (LCV) which is applicable to actual condition is calculated from the HCV. T blIP a e : roperttes 0 IS' 1 R M mgle aw atena Name of the raw Average Bulk density Calorific Value materials moisture content kJ/mJ kJ/kg (%) Rice husk 11.97 127 15608 Rice straw 18.76 72 11823 Saw dust 12.67 140 15296 Bagasse 10.10 63 15430 Table 2: Pro erties of Mixture of Raw Materials Name of Average Bulk density Calorific the Composition moisture kJ/mJ Value mixture of content (%) kJ/kg raw materials 70% rice husk and 30% rise 13.73 99 13339 straw Rice husk 60% rice husk and rice and 40% rise 14.06 98 13212 straw straw 50% rice husk and 50% rise 14.89 97 13190 straw 70% rice husk and 30% saw 12.09 134 15116 dust Rice husk 60% rice husk and saw and 40% saw 12.14 135 15110 dust dust 50% rice husk and 50% saw 12.19 136 15348 dust 37 70% rice husk and 30% 11.29 95 15257 Qa.e:asse Rice husk 60% rice husk and and 40% 11.18 92 15231 baggase b~gasse 50% rice husk and 50% 11.01 84 15110 bagasse 2.2 Pr,operties of Products Moisture Content: Products cut with small pieces were taken and then the test was carried out in the similar manner described earlier. Calorific Value: Samples of products were at first powdered in mortar and then weighted. A sample of 1 gm. was taken each time. Then the previous method of determination of calorific value was followed. " IgnitibiIity: It is the propercy of the product to easily ignitable in normal cooking stores. The low porosity, low volatile. content and high ash content reduces the ignitibility. Different products are burnt in the cooking strove to see the ease of ignition. Stability: It is the property of briquette or the tendency to disintegrate on' exposure to water. Table 3: Properties of Single Product: Name of Current Average Compacti Calorific Ignitibility Stability the raw status moisture on ratio Value materials content (%) kJ/kg Rice husk As found 3.75 9.71 15984 Good Stable Rice Cut into Poor burns Less straw small 6.77 13.81 13279 with lots of dropdown pieces smoke stability Saw dust As found 4.31 6.42 17319 Good Stable Dried and Highly Bagasse cut into 6.58 12.96 15979 Poorest friable and small sensible to pieces . moisture 38 Table 4: Properties of Products Composed of Different Mixture of Raw Materials Name of the Composition Average' ~" Compaction Calorific mixture of raw moisture ratio value materials content (%) kJ/kg 70% rice husk and 30% rise 5.34 11.51 14701 straw Rice husk and 60% rice husk and 40% rise . 4.45 11.41 14586 rice straw straw 50% rice husk and 50% rise 3.50 11.40 14291 straw 70% rice husk and 30% saw 6.91 8.31 14675 dust ,Rice husk and 60% rice husk and 40% saw 4.65 7.87 15980 saw dust dust 50% rice husk and 50% saw 2.71 7.74 16325 dust 70% rice husk and 30% 6.15 11.06 15340 bagasse Rice husk and 60% rice husk and 40% 5.65 11.06 15334 baggase bagasse 50% rice husk and 50% 3.16 11.66 15384 bagasse . 2.3 Economic Analysis The economic analysis of the product (rice husk briquette) and the briquetting system have been done on the basis of one hour capacity of the briquetting machine and the present market price of the raw materials. All analysis is calculated in local currency Taka. The total cost of one complete briqueuing machine = Tk. 38000.00 Economic life of the mad\ine = 10 years Time required to produced,8! kg of briquettes = 1 hour Raw materials required to produce 90 kg of briquettes = 100 kg Raw materials cost per kg = Tk. 0.90 Finished products per kg = Tk. 2.15 Economic life of a screw = 77 hours (considering 25 days operation per month and 10 hours per day) Production cost of screw = Tk. 600.00 Economic life of a die = 750 hours (considering 25 days operation per month and 10 hours per day) 39 Depreciation has been calculated with strai ht r machine conside!red as Tk 200000 f . g - l~e ~ethod when the salvage value of the p ." or Its economIC bfe 10 years ower consumption for electric motOr 12 kW where th' k 5.0 . ' e pnce per Wh electricity is Tk. One labor can operat~ the machine wh h' d . Land cost of the project = Tk. 25000 O~n ITsk a3,loYolabor cost is considered as Tk. 100.00 I '( If' or . .00 rent per month ~l 13 cost 0 the total project = Tk. 10000.00 . Time value of money for the total project has b . . formula,when interest rate is considered as IO%~es calculated conslcten.ng the b~Sic interest Ta~le 5: Total economic analysis of the study can be summarized in the following ways: fue afcost Amount (Taka) Fixed cost 1. Machine cost 2. Land cost 1.27 1.00 3. Installation cost 0.10 Total fixed cost 2.37 Variable cost 1. Raw matehals cost 90.00 2. Machine operating cost a) Die changing COst 0.80 • b) Screw changing cost 17.53 c) Labor cost 10.00 3. Power consumption cost+ Fuel 63.90 Total variable cost (briquette) cost Machine depreciation cost 182.23 1.00 Maintenance cost Total cost 1.00 186.6 Table 6: Profile Analysis: Sales price per 90 kg of briauette Production cost per 90 kg of briquette Net profit per hour per day I per year (300 days in operation) 2.4 Pay Back Analysis Investment: For machine == Tk. 38000.00 For land = Tk. 25000.00 Tk.225.00 Tk. 186.60 Tk.38.40 Tk.384.00 Tk. 115200.00 For installation == Tk. 1000000 Total investment == Tk. 73000.00 . Pay back period == Total investment / (Net annual savings) = 73000.001115200.00 = 0.63 years = 8 months 2% factor of safety has been considered during calculation .. 40 I I ! I sSg'yret? Jar? 3. RESULTS AND DISCUSSION In this study a couple of properties were measured. It is found that the moisture content of rice straw has the highest value and it is about 18.76%. The lowest was bagasse with 10.10%. It is also found that the moisture contents of rice husk and saw dust was to be moderate. In bulk density test, saw dust hold the highest value of 140 kglm3 which is good for transportation and storage. For calorific value test, it is found that rice husks posses the highest calorific value and it is about 15608 kJ/kg on the contrary rice straw has the lowest calorific value of 11823 kJ/kg. For the products, it is found that briquette, made of rice straw has the highest average moisture content of 6.77% and the lowest value i~ for rice husk. It is also found that calorific value of saw dust is the highest and it is about 17319 kJ/kg and the lowest is for rice Slraw of about 13279 kJ/kg. Ignitibility is also an important property and saw dust along with rice husk is found to process better ignitibility than the other two. From table it is found that the product moisture of 50% rice husk and 50% saw dust has the highest calorific value of 16325 kJ/kg which is comparable with that of fuel wood of 19700 kJlkg. Also rice straw can be used as independent raw materials but the product quality is not good and also creates problem during feeding through screw, as a result the production rate is quite low, also it needs preprocessing before use. Blending of rice husk and rice straw is also done which also showed good quality of products but at some cost. Sawdust alone is difficult to densify due to high power consumption though it has a higher calorific value. Rice straw, bagasse and wheat straw needed preprocessing, as these were available in various sizes. During testing it was observed that the length between 0.75 cm to 1.25 cm of the above raw materials is suitable for briquetting making. For the purPose of sizing of raw materials, they were cut into sman pieces. In a die heated electricity driven screw press type briquetting machine, the best product found on the basis of comparative analysis among all the products of the experiment is the 70% rice husks and saw dust with a calorific value of 14675 kJ/kg and with a production rate 72 kglhr. Cost of product is 2.08 TIc /kg. All the products developed in this study fall within the cost range of Tk. 2.00 to·Tk. 2.50. Where as, the traditional fuel woods have the market price of approximately Tk. 3.00. Briquetting process that is performed efficiently served to reduce pore volume of particles and particularly eliminates void volume between solid spaces. AI~o high moisture content in residues reduces the heating value. When fuel is burnt, the net calorific value is always less than the gross calorific value because of some losses associated with vaporization of moisture coming from two sources: a) Inherent fuel moisture and b) water produced by burning hydrogen. In this study in each and every single case it is found that the net calorific value of raw materials increased after densification because the inherent moisture and volatile matters reduced due to the high pressure and temperature of the compaction process. 4. CONCLUSION Considering all parameters rice husk is the most suitable raw materials for briquetting although sawdust shows good properties. • BriqueLtes of plane rice husk have a high production rate of 81 kg/hr with a calorific value 15984 kJ/kg within the limit of the experiments performed throughout this study. 41 1 I / --------... ~--.... ,- ~,., .. • Product from a blend of 70% rice husk and 30% sawdust is found the calorific value, which is 14675 kJ/kg. Its production cost is Tk. 2.08 per kg. This blend is found to be the best of all within the limit of experiment. • . The cost of produ~tion of briquette is comparatively less than that of fuel wood. • The system is economically feasible as it was found that the payback period is 1.73 years. 5. ACKNOWLEDGEMENT Authors acknowledge their profound gratitude to Swedish International Development Cooperation Agency (SIDA) for the financial assistant and also to Energy Program of AIT, Thailand for their technical assistant. Thanks are extended to Grameen Shakti for their kind cooperation and other activities. 7. REFERENCES [lJ Moral, N. A., Biomass Briquetting in Bangladesh, Project report submitted to SIDA, 1998 (2J Bhattacharya, S. C. and Shrestha, R. M., "Biocoal Technology and Economics", Regional Energy Resources Information Center, AIT, Bangkok, Thailand, 1990 [3J Ali, M. N., A final report on Pilot Project on Briquetting of Biomass fuel, December, 1998 Bangladesh statistical Pocketbook, 1999, CD·ROM Version, Published by Bureau of statistical, Bangladesh. [4] Ali, M. N., Final Report on Development and Dissemination of improved Biomass Briquetting System and Briquetting stoves: Renewable Energy Technologies in Asia: A Regional Research and Dissemination program, Phase 11, submitted to AIT, Thailand, December 2001. [5J Website: www.worldenergy.orglwec [6] Website: www.shakti.hypennart.net. 42 

Biomass Briquetting in Bangladesh, Project report submitted to SIDA,

Final Report on Development and Dissemination of improved Biomass Briquetting System and Briquetting stoves: Renewable Energy Technologies in Asia: A Regional Research and Dissemination program, Phase 11, submitted to AIT, Thailand,

An investigation on the raw materials and products of the briquetting machine

http://eprints.usq.edu.au/8189/1/Islam_Khan_Ali_Islam_SRRAESND2003_PV.pdf

An investigation on the raw materials and products of the briquetting machine

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