Carbon dioxide cement industry

The use of the lignin fraction is much more cumbersome currently the best-known chemical of a real commercial importance is vanillin, which is obtained by oxidation of the black liquor. Another example is a product called spray-dried lignosulfonate (as sodium salt) obtained from the older, acidic sulfite pulping process. It is sold as a commercial product primarily as a concrete additive for enhanced strength. Since the cement industry is one of the big contributors of carbon dioxide emissions (due to the production of calcium oxide from calcium carbonate), the use of this renewable, wood-derived product not only is fossil-carbon neutral in itself but also reduces carbon dioxide emission due to the diminished need for cement in large infrastructures made of concrete. 

Carbon dioxide Natural and industrial potential carbon sources exist volcanic activity, living organism respiration, fossil fuel combustion, cement production, changes in land use. Natural CO2 fluxes into and out of the atmosphere exceed the human contribution by more than an order of magnitude. The rise in atmospheric CO2 concentration closely parallels the emission history from fossil fuels and land use changes. 

Uses. In the form of large compact blocks of ordinary limestone or in the form known as marble, large quantities of calcium carbonate are used as building stones. Limestone is also used in building roads, in manufacturing cement, in the metallurgical industries, and as a fertilizer on acidic soils. Calcium carbonate in the form of limestone is the source of all of the lime and much of the carbon dioxide produced in this country. When calcium carbonate is heated to about 900°C, it decomposes, as shown by the following equation ... 

Carbon dioxide Fuel combustion calcining Industrial boilers, cement and lime produc- Greenhouse gas... 

Calcium occurs mainly as calcium carbonate and calcium silicate on earth s crust both are found in limestone. By heating the limestone, carbon dioxide is driven away to obtain calcium oxide. Because of its abundance in nature, it is an inexpensive raw material and is used in various industries including in cement manufacture to tooth pastes. It is available in dilferent grades based on the particle size, purity, and reactivity. 

The worldwide cement composition is —1.6 billion metric tons per year [2], approximately 3% of which is consumed by the oil and natural gas industry. Thus, the annual cement consumption by this industry is —48 million metric tons. The industry, till now, has depended on modified portland cement, but there are niche areas where conventional cement is not reliable. Portland cement has several shortcomings for borehole sealant. It does not set easily in permafrost temperatures, because the water in it will freeze even before the cement sets. Its bonding to earth materials in the presence of oily surfaces is poor. Inherently porous, it cannot form a good seal. A major ingredient, calcium oxide, is affected by downhole gases such as carbon dioxide as a result, cement performance can be poor. These problems can be overcome by a range of CBPC formulations because of their above-mentioned superior properties. 

Cement production is a huge business about 2 billion tons (1.8 metric tons) are produced annually, and this is predicted to rise. Unfortunately, this industry is currently responsible for as much as 10 percent of the world s emissions of carbon dioxide, mostly from the burning of lime. The problem has prompted research into the replacement of calcium with some other easily available material. One possibility is magnesium, as it bonds similarly with silicates. 

Cement production is an energy-intensive industry producing vast quantities of carbon dioxide. In fact, cement manufacturing is the third largest cause of manmade carbon dioxide emissions. Try to limit its use where possible. 

R. Rehan and M. Nehdi (2005) Environmental Science Policy, vol. 8, p. 105 - Carbon dioxide emissions and climate change policy implications for the cement industry . 

The final rule amends the NSPS for coal preparation and processing plants, establishing new emissions standards for particulate matter (PM), opacity, sulfur dioxide (SO2), nitrogen oxides (NOx), and carbon monoxide (CO). The rule does not establish NSPS for emissions of carbon dioxide (CO2), nitrous oxide (N2O), black carbon (a component of PM) or other greenhouse gases from these sources. The revised performance standards are intended to reduce emissions at all new, modified and reconstructed coal preparation and processing facilities at coal mines, power plants, cement plants, coke manufacturing facilities, and other industrial sites that process more than 200 tons of coal per day. 

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