
A bed of 12 kg graphite (100% C) is burnt in air.
Calculate the following:
(i) Theoretical air required in m3 ,
(ii) Volume of products of combustion in m3 and (
iii) Flue gas per cent analysis.
Coal analyses C–84%, H – 4%, N–1.4%, O–1.8%, S–0.64%, and total inorganic oxides (ash) 8.16%. This coal was burnt in pulverized form with excess air to ensure complete combustion. The dry gaseous product of combustion analysed CO2 –15.7%, O2 –3.6%, SO2 –0.04% and N2 –80.7% at STP.
Calculate the following:
(i) Theoretical amount of air needed for combustion in cubic meters per kg coal
(ii) Percent of excess air used for combustion
(iii) Total dry gaseous product of combustion in cubic meters per kg coal.
A dry coal analyzing 78% carbon, 8% hydrogen, 2% oxygen, 2% nitrogen and 10% ash was burnt in a furnace. The furnace used 10% excess air during combustion.
Calculate the following:
(i) The amount of theoretical air needed for combustion in m3 /kg coal
(ii) The amount of actual air used during combustion in m3 / kg coal
(iii) Flue gas volume using excess air in m3 /kg coal
(iv) Flue gas analysis on dry basis using excess air.
5 A coal contains 78% carbon, 4% hydrogen, 2% oxygen, 1.8% sulphur and rest as non-combustibles.
Calculate the following:
(i) Gross calorific value of the coal in GJ/ton using Dulong’s Formula 337 C + 1442 [H – (O/8)] + 93 S kJ/kg where C, H, O and S are percentages of carbon, Hydrogen, oxygen and sulphur respectively.
(ii) Amount of coal needed per day to burn in a 10 MW power plant working with 32% thermal efficiency (Given 1 kWh = 3.6 MJ).
A natural gas analyses as: CH 4 – 85%, C 2 H 4 – 3%, C 6 H 6 – 3%, H 5%, N 2 – 4%. It is burnt with 20% excess air. The air is moist containing 1.5% water vapour.
Calculate the following:
(i) the dry theoretical air needed for burning one cubic meter of natural gas,
(ii) volume of moist air used for burning including excess air
(iii) volume of product of combustion at STP and its analysis.
Consider 100 m3 of the mixed gas is used for combustion which contains 80% (or 80 m3 ) blast furnace gas and 20% (or 20 m3 ) coke oven gas whose gas analysis is provided in the problem.
This course delves into the intricate processes and design considerations involved in combustion, a cornerstone of energy production across various industries. From solid to liquid and gaseous fuels, students will explore the complexities of combustion systems, gaining invaluable insights into optimizing efficiency and minimizing environmental impact.
The importance of air in the combustion process is emphasized, alongside the crucial factors influencing combustion system design. Solid fuels are studied in depth, covering combustion systems ranging from smith shop furnaces to small-scale boilers. Students will learn the mechanics of solid fuel bed combustion, including fuel selection and preparation, as well as the merits and limitations of pulverized fuel combustion.
In the realm of liquid fuels, the course delves into atomization techniques, burner types, and ignition systems, ensuring students grasp the nuances of combustion mechanisms and flame properties. The distinction between complete and incomplete combustion is highlighted, emphasizing the importance of efficiency and emissions control.
Gaseous fuels are also explored, with a focus on combustion behavior and flame propagation. Various burner types used for gaseous fuels are analyzed, providing students with a comprehensive understanding of combustion systems across different fuel types.
Throughout the course, practical applications in power generation and environmental sustainability are underscored. Students will emerge equipped with the knowledge and skills necessary to tackle real-world challenges in engineering, environmental science, and related fields, making meaningful contributions to energy efficiency and environmental stewardship.