Ram Gopal Sharma

A review of coke making by-products

Existing energy resources are struggling to cope with the current energy requirements. It is therefore, necessary to increase energy efficiency and reduce greenhouse gases emissions in integrated steel industries. The yield of coking by-products is one of the key ways to achieve these goals. This review article is focused on history of the by-products such as coal tar, coal tar pitch, ammonia, hydrogen sulphide, pyridine, hydrogen cynide and carbon based material. Different technology for removal of mentioned by-products are briefly described according to technology development at different stage. Yield and quality of coking byproducts, its impacts on carbonization processes and factors such as volatile matter, rank of coal, reactive macerals, elemental constituents, and temperature were also investigated.

A comparative study of by-products yield from coke making processes in a Jenkner apparatus

Physico-chemical characteristics or the industrial behaviour of any coal is directly controlled by its organic micro-components (macerals). The yields of by-products during carbonization of coal are affected by organo micro-components of different coals and operating parameters, such as, charging technologies, carbonization temperature, particle size, bulk density, etc. In the present investigation, the effects of volatile matters (16.61–36.00%), Ro, avg. (0.80–1.36%), exinite (0.5–4.5%), hydrogen (4.34–5.29%) and nitrogen (1.60–2.18%) content of coal on yield of by-products, such as, coke oven gas, coal tar, ammonia, and hydrogen sulphide were studied. The studies revealed that there is a significant difference of the yield of by-products for the two different charging technologies. The coke oven gas, coal tar and ammonia yield was lower in stamp charging process as compared to top charging process, whereas, hydrogen sulphide yield followed a reverse trend.

An approach to maximize the use of non-coking coal in non-recovery coke making

The preservation of metallurgical coal and coke cost reduction are gaining much importance in iron and steel industry. The effort is being made worldwide to increase the use of inferior grade coking coal/non-coking coal in coke making. The objective of this study was to maximize the use of non-coking coal in the coal blend without deteriorating the coke quality in non-recovery coke oven. The selection criterion of coal/coal blend was based on a coefficient, named as composite coking potential model. The study confirms the existence of a relationship between the composite coking potential and the hot strength of coke. The study reveals that upto 35% non-coking coal in coal blend is possible to produce desired quality of coke with coke CSR ≥ 65.

Electrothermal Behavior of the Joint of Binary Current Lead of Conduction-Cooled Magnet

A 6-T cryogen-free NbTi magnet system with a warm bore has been developed using a two-stage cryocooler (CCR). The binary current lead is one of the main components of any conduction-cooled magnet system. The heat flow scheme through the binary current leads greatly determines the operating points and the thermal stability of the magnet system. A pair of binary current leads has been developed for a 102-A current to achieve a 6-T field. The thermal interception of a binary current lead along with their electrical isolation to the corresponding cooling stages of the CCR greatly influences the electrothermal behavior of the lead, which eventually influences the stability of the magnet. Low-electrical-resistance and low-thermal-resistance joints have been developed for the binary current leads. The equilibrium temperatures are 37.75 and 4.55 K, respectively, for the first- and second-stage lead joints at zero current. In addition, the corresponding equilibrium temperatures of lead joints are 42.04 and 6.55 K at 102-A current. The average thermal impedance of the corresponding joints is measured to be 0.6 and 13.7 K/W.

Experimental studies on thermal behavior of 6 Tesla cryogen-free superconducting magnet system

A 6 T cryogen-free superconducting magnet system (CFMS) with warm bore has been designed, built and tested for carrying out physical property measurements at high magnetic field. The CFMS has a vertical Ψ 50 mm clear room temperature working bore. A two-stage GM-cryocooler of 35 W at 50 K and 1.5 W at 4 K cooling capacity has been used to cool the thermal radiation shield, hybrid current leads and the NbTi magnet. The magnet was charged to 102 A, which produced a field of 6 T, in less than 20 minutes. The outer surface temperature of magnet rose from 3.3 K at zero current to 3.9 K at 102 A current. The thermal link between cold head and magnet greatly influences the excitation rate and the stability of the magnet. Based upon our thermal analysis on the magnet system, an experimental study has been carried out on the thermal behavior of the magnet during its operation. A novel technique has been used for connecting the high temperature superconducting current leads to the magnet so as to reduce both electrical and thermal contact resistance at the 2nd stage of the cryocooler. This paper briefly describes the design, development and results of experimental studies of thermal behavior of the system.

Peformance test and thermal analysis of conduction-cooled optimized current leads at non-optimum operation

Current leads are the key components which make an electrical connection between room temperature power supply and superconducting magnets at 4.2 K. In any cryogenfree magnet system, major heat input comes from the copper current leads of the magnet. The dimensional optimization of the copper part of the hybrid current leads is done for a particular operating current between room temperature to the operating temperature of the 1stst stage of cryocooler (CCR). The conduction-cooled magnet may not necessarily be operated at the optimized current all the time. Hence for non-optimum current, the heat input per unit current will be increased both at under-current and over-current operation. The stabilized temperature, of the 1st stage of CCR corresponding to each operating current, would mainly be governed by the dynamic heat input by the current lead. A pair of copper current leads working between the temperatures 300 K to 33 K has been optimized for 85 A optimum current. A simple analytical technique has bee...