Vol 6 No 1 (2024)

Published: 2024-03-21

Abstract views: 332   PDF downloads: 70  

Page 313-322

Corrosion of austenitic Fe-Ni based alloys with various chromium and aluminum additions in a carburizing-oxidizing atmosphere at 800ᐤC

blankpage Shu Liu, Yong Zhu, JunJie Cao

The corrosion behaviors of Fe-19Ni-13/21Cr-xAl (x = 0, 2, 6 at. %) alloys in a carburizing-oxidizing atmosphere were compared with those in a purely carburizing atmosphere at 800oC. For alloys with 13 at. % Cr, 2 at. % addition of Al did not improve the corrosion resistance effectively but induced a slightly increase of the total mass gain. 6 at. % addition of Al produced a large decrease of the total mass gain, therefore the corrosion resistance was improved significantly. For alloys with 21 at. % Cr, additions of Al did not affect the total mass gain obviously. Fe-19Ni-21Cr-xAl (x = 0, 2, 6 at. %) showed similar mass gain. Increase of Cr content from 13 at. % to 21 at. % is effective for protecting the alloys from the carbon attack for Al-free alloys and alloys with 2 at. % Al. However, addition of Cr is not so helpful for alloys with 6 at. % Al. The addition of oxygen improved the corrosion resistance of all alloys significantly except the Fe-19Ni-13Cr-6Al. Pure external chromia scales on alloys without Al and with 2 at. % Al could not suppress the inward diffusion of the carbon atoms. Aluminum and chromium worked together to form mixed oxide scales inhibiting the carbon attack totally on alloys with 6 at.% Al.

Abstract views: 505   PDF downloads: 111  

Page 306-312

Hydrocarbon fuels, combustion characteristics & insulating refractories in industrial furnace

blankpage Mahesh Borate, Prashant D. Deshmukh, Arunkumar Shetty

Liquid fuels like Furnace Oil, Light distillate oil, Diesel & gaseous fuels like PNG (Piped Natural Gas), LPG (Liquefied Petroleum Gas) are predominantly used at present in industrial applications. Single fuel, Dual fuel & Multi-fuel options are available in the market. All these fuels are called hydrocarbon fuel. A loss of drop of oil in every second can waste about 4000 liters in a year. Selection of right type of fuel depends on various factors like availability, storage, handling, Pollution & landed cost of the fuel. These different fuels used for combustion in industrial furnace are discussed herewith. Complete combustion in industrial furnace enhances efficiency, control pollution as well as global warming. Efficient use of fuel leads to complete combustion. This paper deliberates about combustion of fuel and how complete combustion is to be achieved in industrial furnace. Stoichiometric ratio ensures complete combustion. Industrial furnace uses refractories to form a combustion chamber with proper insulation to ensure temperature within the combustion chamber is as per requirement of the job. The outside skin temperature of industrial furnace is about 35ºC to 45ºC from safety point of view. To maintain this temperature difference with minimum wall thickness needs proper refractory selection which must withstand high temperature. The main objective of this research paper is to propose strategies to select the right fuel, proper insulating material to achieve complete combustion & minimum heat losses through the walls of combustion chamber. This will help in making an efficient design and optimize combustion controls to keep heat losses at minimum level.