Charcoal Briquette Essay

Charcoal is defined as dark grey residue consisting of impure carbon obtained by removing water and other volatile constituents from animal and vegetation substances [1] or a black grey form of carbon, produce by heating wood or other organic substances in enclosed space without air. Charcoal is basically composed of tiny particles or carbon[2] which is usually produce by slow pyrolysis, heating of wood, sugar, bone char, or other substances in the absence of oxygen resulting in soft, brittle, lightweight, black, porous material which resembles coal and is about 50 percent to 95 percent of carbon[3].

The traditional way of producing charcoal is ‘the Kiln process’ is normally associated with huge amount of smoke which is a major contributor to the depletion of ozone layer but with the help of Orin Stafford, who helped Henry Ford established his briquette business developed an alternative method of producing charcoal in the early 1900s called the retort method. The retort method involves passing wood through a series of hearths or oven. It is a continuous process wherein wood constantly enters one end of a furnace and charred material leaves the other.

Virtually no visible smoke is emitted from a retort, because the constant level of output can effectively be treated with emission control device such as afterburners [4]. Charcoal could be found in several forms which include activated charcoal, lumps, extruded charcoal and briquette. Activated charcoal is a kind of charcoal with higher carbon composition, is made at elevate temperature in a chamber where air and oxygen are pumped out to ensure fewer impurities.

The lump charcoal is made directly from hardwood material and usually produces far less ash than briquette. The extruded charcoal is which is made by extruding either raw ground wood or carbonized wood into logs without the use of binder. The heat and pressure of the extruding process holds the charcoal together but if the extrusion is made from raw wood material, the extruded logs are then subsequently carbonized. Unlike extruded charcoal, binders are used to bind crushed charcoal particles together to form briquettes.

Briquettes would be discussed in detail later in this project. 1. 2 Briquetting Technology A briquette is a block of flammable matter used as fuel to start and maintain a fire. Briquetting is the transformation of a powdery or granular product into a larger more convenient size which is accomplished by compacting, the product with a roller press sometimes with or without a binder material [5] or the physical transformation of the loose raw material into high density fuel briquettes through compacting compressed units.

Briquetting is the only way to change the powdery material into briquette which is suitable for transporting and is energy-saving. This form change results in a much higher specific density of the material which increases its combustion efficiency as compressed to the loose material. Charcoal is a material totally lacking plasticity and hence needs addition of a sticking or agglomerating material to enable a briquette to be formed. The binder should preferably be combustible, though a non-combustible binder effective at low concentrations can be suitable. FAO, 1983) Based on the characteristics of the processed material, the binder used and the desired end product, the briquette can be produced with high or low pressure and can undergo mechanical or thermal treatment. The most common types of briquettes are charcoal briquettes and biomass briquettes. 1. 3 Invention of Charcoal Briquette Charcoal briquette was invented by Henry Ford along with his friend Thomas Edison in 1920 even though Zwoyer still had the patent. Ford created briquette from the wood scraps and sawdust left over in his model T. car factory.

Later, Fords brother-in-law, E. G. Kingsford bought Fords briquette, which was originally called Ford Charcoal and formed the Kingsford company and made the briquette available everywhere and now sells over ten different kinds of charcoal[9]. 1. 3. 1 Raw Materials for Charcoal briquette Millions of tons of agricultural wastes are generated every year which are either destroyed or burnt inefficiently in loose from causing air pollution. Theses wastes can be recycled and can provide a renewable source of energy by converting biomass waste into high density fuel briquettes.

With the exception of papers or waste papers, the raw materials for charcoal briquettes are can be grouped into 2 which are agro wastes and forest wastes. The agro wastes are mustard waste, rice husk, arhar stalks, coconuts husks, palm kernel, cocoa pods, groundnut shells, pine needles sarkanda, bagasse, coffee husk, cotton stalk, sunflower and waste, sugarcane bagasse, leaves and trash, maize stalks, bar cobs, coir dust whiles the forest wastes includes wood chips and shavings, tree bark and twigs, sawdust, bamboo and bamboo leaves, wild grasses and shrubs.

The above raw materials can be briquettes with or without using any binder and the briquette normally contains calorific value of about 3500-4800K. cal/kg [6]. It is completely sustainable, however, the modern briquette manufacturers do take the environment seriously and now manufacturer their char from wood shavings and sawdust i. e. the waste product of the lumber industry [7]. 1. 3. 2 Charcoal briquette Charcoal briquettes are made by compressing charcoal, typically made from sawdust and other wood by-product, with a binder and other additives.

The binder is usually starch. Some briquettes may also include brown coal (heat source), mineral carbon (heat source), borax, sodium nitrates (ignition aid), limestone (ash-whitening agent), raw sawdust (ignition aid) and other additives like paraffin or petroleum solvent to aid in ignition [3]. About 90 percent of charcoal briquettes are made up of two primary ingredients. The first one, char is the primary reason briquettes produce the Smokey wood flavor and it allows the briquettes to easily light.

Coal is the second primary ingredient which produces the high temperature and continuous burning required for grilling and the last 10 percent of charcoal briquette is generally made up of minor ingredient which acts as accelerants and binders [2]. 1. 4 Binding agents for Charcoal Briquettes The binders for charcoal briquette may be classified into smokeless and smoky binders. Smokeless binders are normally meal binders which include cassava starch, corn starch, wheat and other starches. The smokeless binders are not moisture resistant and are used in the range of 4-6 percent on the oven-dry basis.

In some cases, small amount of moisture resistant binders are used. Smoky binders on the other hand are smoky but moisture resistant binders which comprises of tar, pitch, asphalt, sugarcane molasses and others. Normally, recommended percentage for wood-tar pitch and coal-tar pitch are less than 30 percent. Briquettes with this kind of binders are smoky when ignited or lighted but the characteristics are not a drawback for briquettes used in smelting and heating.

1. 4. 1 Effect of binding agents. A tropical root crop like cassava is often used as a binding agent; it is quite robust and can be grown in infertile soil and has also unique properties such as its high viscosity and resistance to freezing [8]. The binding agents or binders are needed when the pressure produced by compacting equipments is too low for self-bonding and also is to enhance cohesion and reduce pressure requirements. The binder holds components by both mechanical and chemical adhesion and occurs when the binder molecules adhere to specific point in the molecules or structure of the adherent.

The commonly used binding agents includes starches from cassava (manioc), corn, wheat, sugarcane molasses, tar, pitch, resins, glue, fibers, fish waste and certain plant like algae. 1. 5Other briquettes Some briquettes are compressed and dried brown coal extruded into hard block which is a common technique for low grade coal [3]. They are primary used in household and industry which normally dried up to 12-18 percent moisture, and include; peat and biomass briquette. 1. 5. 1Peat briquette

Peat is a compact, dark brown organic material with high carbon content, built up by partial decay and carbonization of vegetation in the acidic water bogs, consists mostly of mosses in the northern hemisphere [10]. There could also be salt peat which is developed in the salt marshes from partially decayed portion of such plants as the cord grasses. The dried peats are often compressed into briquettes which are commonly type of solid fuel, largely replacing sods of raw peat as a domestic fuel. These briquettes consists of shredded peat, compressed to form a virtually smokeless, slow burning, easily stored and transported fuel.

It is not efficient as coal because of its large content of water and ash, sometimes used as fuel for a fire, and also used to quickly and easily lights a coal fire. The commercial preparations of peat, partially decayed vegetable matter that have excellent moisture-retaining qualities are used as mulching and soil-improving material for plants. Peat bogs are distributed throughout the world and extensive deposited are found in the northern United States, Canada, Russia, the Scandinavian countries, England and Ireland [10].

1. 5. 2Biomass briquettes. These are renewable source of energy and avoid adding fossil carbon to the atmosphere, made from agriculture waste and are a replacement for fossil fuels such as oil or coal which can be used to heat boilers in manufacturing plants and also have applications in the developing countries. In India for instance, a number of companies and units have switched from furnace oil to biomass briquette as boiler fuel to save cost on boiler fuels. The use of biomass briquettes is predominant in the southern parts of India because, it also provides more calorific value/Kg and saves around 30-40 percent of boiler fuel cost[3].

A popular biomass briquettes emerging in developed countries take a waste product such as sawdust, compressed it and then extrudes it to make a reconstituted log that can replace firewood, which is similar process of forming a wood pallet but on a larger scale and requires no binder, the natural lignin in the wood binds, the wood particles together to form a solid. The moisture content of such briquettes can be as low as 4 percent whereas green firewood maybe as high as 65 percent which makes burning of a wood briquette is far more efficient than burning firewood.

Saw dust briquette is an example of biomass briquette that has developed over the years with two types which are distinct in technique; those with hole through the centre and those that are solid based on type of press used. Briquettes with hole through the centre are produced with a screw press in which the hole is from the screw thread passing through the centre which increases the surface area of the log and aid efficient combustion whiles the manufacturing of solid briquettes are done by piston press that compresses the sandwiched layers of sawdust together.

Companies like Nishant Bioenergy and Ekta Bioenergy in Rajasthan, India are leading manufacturer and supplier of these briquettes [3]. 1. 6Purpose of Study Across town, city and even country, a lots of wastes are being generated especially from coconut husks and palm kernel shells which are being dump or left untreated but this wastes can recycled and used as fuel. It is the significance of this work to produce fuel (charcoal briquettes) from this agro waste such as coconut husks and palm kernel shells. 1. 7Uses of Charcoal The use of charcoal may be categorized into various fields which includes;

a. Fuel for cooking: In many non-industrialized country, charcoal is use domestically as the main source of fuel for cooking everyday by a large portion of the population whiles in the develop world, charcoal briquette are widely used for outdoor grilling and barbecues in backyard and on camping trip. It is used in metallurgical operations for smelting and sintering iron ores, production of Ferro-silicon and pure silicon, case hardening of steel, purification agent in smelting non-ferrous metals, fuel for foundry cupolas, electrodes. FAO, 1983) b. Gas generator: Charcoal is use to produce gas for vehicles and also for carbonation of soft drinks. c. Treatment of liquids -Water, fats, oils and beverages purification. -Cleaning of bottles and tanks in wineries, for insecticides and pest,and of electroplating bath. -Decolourization of cane and beet sugar solutions, vitamin solution and pharmaceuticals and high fructose syrup.

d. Treatment of gases and vapors -Purification of exhaust emission of recirculates air pollution -Reduction of toxic and harmful vapor levels Air purifier for commercial and domestic kitchens -Gas marks for military and civilians -Recovery of solvent from printing machines and processes where highly volatile matter is continuously being released. e. Miscellaneous uses Some of these uncountable uses may include catalyst for chemical processes, support for platinum and palladium catalyst, pharmaceutical, cigarette filters, food additives, depolarizer in electric batteries, additives in rubber tires evaporation control system and evaporative air coolers. . 8Importance of Charcoal briquette The because of the starch which has been used as binder, charcoal briquette reduce the emission of carbon dioxide into the atmosphere thus environmentally friendly. Charcoal briquette has replaced the traditional charcoal for cooking and is also burnt in a fire place to warm room on cold days. In this project most of the files used are obtained from the internet, Microsoft Student Encarta services.