Biomass can be used in cement plants through two major modes, namely direct combustion and transformation into producer gas. Direct combustion of biomass in pre-heaters / pre-calciners and in the kiln by part-replacing the fossil fuel used in raising the temperature of the raw meal. This can happen in two ways: first, by mixing crushed and pulverized biomass with coal or petcoke for use in the kiln, and secondly, by direct feeding of biomass in solid lump form (such as pellets and briquettes) into the rotary kiln and / or pre-heater/pre-calciner combustion chamber. The biomass can also be transformed into producer gas (also known as ‘synthesis gas’ or ‘syngas’) and co-firing it in the kilns using a gas burner (Seboka et al., 2009).
Briquetting Plant Exporter and Manufacturer offers Biomass Briquetting Equipment. Up to now waste from industries or any kind of agriculture waste are dumping into sea or environment. Now a days peoples become aware of saving environment and energy. Briquetting plant manufacturer gives best solution for renewable energy by introducing renewable briquetting plant project. This Agro Briquette Plant Project convert all types of agriculture and forestry waste into a Biomass Fuels. Further these Briquettes are used into industries for energy purpose . there are number of Bio Coal Machine Manufacturer . These Briquetting Machine Manufacturer made dam easy to convert waste into solid fuel called Biomass Briquetting. Everyone is familiar with the side of this waste. The environment is continuously become degrade with this waste. That is what these manufacturers have kept in mind and brought an innovation called Biomass Briquetting Project.Fuel Briquette Machine Plant take these waste as a input and treat them in a echo friendly way and what we get is called Biomass Briquettes. These Briquettes are used for generating heat into boilers. We the Radhe Industrial Corporation offer our client an excellent quality range of Briquetting Plants because 85 to 90 % of its parts are manufactured at our plant with advance & highly technological machineries. We are not the assembler but we are the real manufacturer of Briquetting Press. We offer the best competitive price compare to others with world class quality.Bio-mass briquettes are made from the Agriculture waste and forestry waste. It is binder less technology so there is no requirement of any chemical, adhesive or binders for the binding. It is been converted into solid cylindrical shape. The major residues which can be used are Ground nut shell, Cotton stalk, Sugarcane baggasse & leaves, Rice husk, Saw dust, Mustard stalks, Caster seeds shells/ stalk, Wood chips, Coffee husk, Paddy straws, Wheat straw, Sunflower.
Cement is used as a binder for briquetting coal, char, and charcoal and then for briquetting iron and steel wastes. Now cement is widely used in the steel plant as one of the main binders. But use cement will bring gangue and crystal water, so to reduce the cement cost can help to increase the purity of briquette, as cement need a long time to get an ideal strength, add other binders with small dose will improve this work, like sodium silicate, etc.
In most kiln systems the fuel ash is incorporated into the clinker thereby changing the compound composition of the product. The main constituents of fuel ash are silica and alumina compounds which combine with the raw materials to become part of the clinker. The composition of fuel ash tend to limit the level of replacement of more conventional fuels, for instance rice husks have been used to replace 5 – 7 percent of traditional fuels since the ash contains 78 – 90 percent silica. Fuel ash with high content silica can on the other hand provide a very satisfactory means of increasing the silica modulus of the clinker, thus making it possible to reduce the amount of ground sand incorporated into the feedstock (Hewlett, 2004).
The cement industry, like other industrial sectors, is strictly regulated by the national and international legislation as well as internal regulatory procedures regarding environmental protection, health and safety, and quality of products. Strict regulations are applied and plants are operated on the basis of permits from national authorities. Emissions are regularly checked by the authorities. Special approval from relevant authorities is therefore required to burn alternative fuels in many countries on account of potential environmental hazards (Hewlett, 2004).
The crushed rock is combined with other ingredients such as iron ore or fly ash and ground, mixed, and fed to a cement kiln.
The incomplete combustion, poor heat distribution and unstable precalciner operation are problems associated with switching from conventional fuel to alternative fuels (Roy, 2002). The arrangement of combustion in such a manner as to create a reducing condition in some zones of the precalciner is useful for the diminution of NOx emissions. On the other hand, it is important to note that low combustion efficiency at the precalciner stage can create reducing zones in deposited material at the kiln inlet, significantly increasing the volatilization rate of sulphur (Ghosh, 1991). Desmidt, 1987, observed a 78 percent volatilization of SO3 at 93 percent combustion and 0.2 percent CO at kiln inlet, and a 42 percent volatilization of SO3 at 98percent combustion and 0.06 percent CO at kiln inlet. Incomplete combustion also gives rise in the carbon content in the product. This is undesirable for the following reasons. First, high carbon content accelerates corrosion of steel in concretes. Secondly, the carbon absorbs water reducing the quantity available for hydration reaction. Thirdly, the alkalinity of the cement is affected. Finally, high carbon content ash darkens the concrete reducing its aesthetic appeal and leading to inaccurate prejudgements of the concrete quality (Ha et al., 2005; Freeman et al., 1997; CIF, 2000).
The most common way to manufacture portland cement is through a dry method. The first step is to quarry the principal raw materials, mainly limestone, clay, and other materials. After quarrying the rock is crushed. This involves several stages. The first crushing reduces the rock to a maximum size of about 6 inches. The rock then goes to secondary crushers or hammer mills for reduction to about 3 inches or smaller.
Below is an example of a sand to cement mix ratio recommendation from a cement manufacturer.
Concrete and mortar can be made from a mixture of masonry sand and either Portland cement or masonry cement. The addition of hydrated lime makes the concrete more plastic-like when it's wet and stronger and more durable after the concrete hardens. Masonry cement comes with lime already included.
That's a big problem for the climate, because the process releases large amounts of carbon dioxide. The industry's huge carbon footprint partly stems from its high fuel requirements, which are mostly satisfied by fossil fuels. But more than half of its emissions—and perhaps as much as two-thirds, by some estimates—actually come from the chemical production process itself, which releases large amounts of carbon dioxide as a byproduct.
The formation of poisonous solid and gaseous by-products during sludge incineration is, however, noted to be a source of public concern. These include the release of heavy metals and the emission of substances such as NOx, N2O, SO2, HCl, HF and CxHy (Ogada &Werther, 1996). SO2 emissions in pulverized fuel fired systems normally correlate strongly with the sulphur content of the fuel and generally almost all the sulphur in the fuel is released as SO2 (Spliethoff & Hein, 1998; Werther & Ogada, 1997). The sulphur content of the sludge is comparable with that of coal.
The quality, type and quantity of fuel exert a profound effect on the quality of clinker produced. Consequently, selection of the proper type of fuel is vital for optimum efficiency. Waste derived fuels have different characteristics compared to conventional fuels such as coal and to be able to use them in cement manufacturing, knowledge of their composition is important. The energy and ash content as well as the moisture and volatile contents are all important limiting factors. A comparison of coal with some of the most common alternative fuels used in cement kiln systems is presented in Table 3. Ultimately, cost and availability of the alternative fuels remain the main influencing factors for their choice.