BOMB CALORIMETERS IN STEEL MANUFACTURING
The large CO2 emissions from the steel industry and the concern for global warming are opening options to reduce fossil derived CO2 emission sin a steel plant by using biomass, but still keeping the production costs of steel reasonable.
The worldwide steel industry is responsible for around one fifth of all industrial CO2 emissions. Hence it has a significant impact on the environment and thus is a good place to look for alternative solutions. One of these alternatives, without loss of productivity or reduced quality, is to take a step back, namely the use of biomass as a secondary fuel in the production process of steel.
Steel, presently a widely used construction material that is both endurable and strong, is one of the most important metals in our modern society. It is a metal alloy with its main component being iron, which is much stronger than the latter due to its carbon content.
Energy has always been – and will always remain – one of the most important production factors within the iron and steel industry. From an energy consumption viewpoint, the ore-based steel plants are wholly dominant. This is due to coke, which is required as a reducing agent and for alloying processes, being included in the energy balance.
One characteristic of the steel industry is that most of the energy-intensive processes take place at extremely high temperatures. The energy is used mainly in processes where the working temperature exceeds 1000°C. These circumstances mean that steel plants – in order to maintain production – need to have access to energy resources of high calorific value (which is measured using an oxygen bomb calorimeter system) such as coal and oil products, gas and electric power.
The combustion of fuel occurs in the same compartment as the material to be heated; this places special requirements on the atmosphere and the fuel’s ash content in order to ensure that the material quality does not undergo deterioration or show too much variation.
In line with the expanded possibility for transporting liquefied natural gas, natural gas is increasingly being used as a replacement for oil. To a certain extent the use of fuel is also being replaced by electric power. On the other hand, coal cannot be replaced to any extent since it is primarily used as a reducing agent.
Some of the following materials are used to generate heat and energy during the steel manufacturing process and can be analysed for quality and heat energy using a bomb calorimeter system :
Coke is produced from pit coal and used mainly in the reduction processes, i.e. in blast furnaces.
A certain portion of the coke can be replaced by pulverised coal, oil, and tar. The coke oven gas from the coking process is used as a fuel in coking plants and blast furnaces but also in the reheating and heat treatment furnaces of rolling mills.
Oil is used especially in oil-fired furnaces for reheating and heat treatment operations in rolling mills. The use of oil has been sharply reduced since the 1970’s for the following reasons :
- There is a reduced demand for heat in rolling mills
- Pulverised coal injection is used
- Energy efficient measures
The worldwide tightening of energy supplies represents a constraint on the ongoing expansion of integrated steel production. The efficient utilization of lower quality by-product fuels represents at least a portion of the solution to this problem.
Wood could also be grown in plantations for use in the steel industry, just as it now grown for timber. But land is a limited resource and is also needed for food and buildings and the protection of wild nature and other species.
However, all existing forestry operations have residues of woody material of low commercial value. As well as prunings and thinnings, harvesting residues like branches, bark and damaged logs average at least half a tree. Woody waste from crops – such as coconut shells and husks, corn stover, grain stalks – can be added to this. Annual waste from commonly cultivated crops is in the region of 25-176 exajoules (Ej – 1018 joules). It would take approx.. 1.6BT biomass globally to replace all the coal currently used in iron and steel making.
By analysing the above by-products from forestry and lumber industries, it can be determined whether by-products are a sustainable source of energy to replace coal and oil in steel manufacturing. This process can be complete with the help of an oxygen bomb calorimeter to determine the calorific value of the by-products and comparing it to the heat energy value of the coal and oil.
The oxygen bomb calorimeter plays a small but significant role in determining the calorific value of the fuel used in iron and steel making, and can be used to determine which by-products can be used to replace fossil fuels (thus contributing to a greener environment as well).
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PULP & PAPER MILLS
Pulp and paper mills generate various quantities of energy-rich biomass as wastes, depending on the technological level, pulp and paper grades and wood quality. These wastes are produced in all stages of the process : wood preparation, pulp and paper manufacturing, chemical recovery, recycled paper processing, waste water treatment.View Application
PULP & PAPER MILLS
Solid biomass fuels are useful and a cost effective renewable energy source. The energy content of the biomass is determined by its calorific value. The calorific value of different forest species and bio-based industry residues can be used by companies specializing in processing raw biomass solid bio fuel production, small-scale consumers.View Application
Only explosives which can be ignited by heat from the calorimeter's firing circuit can be tested in the oxygen calorimeter. Then very minute/small quantities are used for analysis. The calorific value of an explosive is not very high, but the burning speed is.View Application