Furnace Load Research Articles

Local particle velocity, size, and concentration measurements in an industrial-scale pulverized coal-fired boiler

Parametric, in situ, particle velocity, size, and number density measurements have been made in a full-scale, coal-burning power plant using an optical diagnostic technique. Available ports in the boiler allowed measurement at three locations above the burner level. Variable test parameters included furnace load, excess air, and burner tilt, using a medium volatile bituminous coal. Higher particle velocities were observed when the boiler was operated at maximum capacity due to increased air and coal flows. Port-to-port velocity variations were attributed to the rotational nature of the mean flow, changes in gas density with changing gas temperature, and the interaction of the flow with the boiler nose. Measured particle number density profiles were characterized by high values in the small particle size class (< μm), decreasing exponentially with increasing particle size. The measured number density profiles indicated that the combustion process is largely complete at locations 7 m above the burners and that the particles measured consisted primarily of ash, a conclusion which is also supported by the percent carbon-in-ash data. The mass-mean and number-mean particle sizes for all tests varied between 10 and 45, and 0.5 and 0.85 μm, respectively. The characteristic similarity between the particle size distribution of the ash and that of the parent char, previously documented in laboratory scale investigations, was also observed in the present study. Cumulative mass distribution profiles indicated that a significant centrifugal effect is exerted on the condensed phase by the rotating flow. An increase in small particle number density (∼ 0.5 μm) was also apparent at lower boiler loads due to changes in the combustion process occurring at these operating conditions, which affect the various modes of ash particle formation.

Atmosphere carburizing at 927° C (1700° F) for distortion control

A reduction in the magnitude of out-of-round (OOR) and improved flatness of heat treated but unfinished tapered roller bearing components was achieved by carburizing parts at temperatures less than 927°C (1700°F) in a controlled, integral-quench process. Distortion results from this study are compared to conventionally processed components. Reasons for reduced distortion levels achieved are discussed in terms of temperature uniformity, atmosphere control, quenchant temperature, quenchant flow and postquench processing steps, product fixturing, and product orientation in the furnace load.

Modeling of a Resistance Regulated ARC Furnace

An electric furnace is a load with a definite impact on the power system. Some of the impacts include harmonics, voltage flicker, and increased power system losses. The objective of this study was to develop a model for analysis of the electrical characteristics and electrical parameters affecting the behavior of an are furnace load. The model developed is based on steady state analysis, but through further model refinement dynamic analysis may be studied.

Modeling of A Resistance Regulated ARC Furnace

An electric arc furnace is a load with a definite impact on the power system. Some of the impacts include harmonics, voltage flicker, and increased power system losses. The objective of this study was to develop a model for analysis of the electrical characteristics and electrical parameters affecting the behavior of an arc furnace load. The model developed, is based on steady state analysis, but, through further model refinement, dynamic analysis may be studied.

Direct measurement of furnace load temperature using 3.9 μm radiation

The results of two carefully controlled trials indicate that a remarkably precise estimate of billet temperature in a steel billet reheating furnace can be derived from a simple measurement of 3.9 ...

Control of overall thermal efficiency of combustion heating systems

A method for analyzing the energy performance of central combustion heating systems has been derived. The method consists of a combination of measuring a minimum number of key system parameters and using them as input for HFLAME, the digital model used to simulate the dynamic performance of the heating system. HFLAME is based on the stack loss method, uses only input that can be obtained during field measurements, and relies on the steady state operation of the burner to calibrate flows and temperatures. This methodology is being applied to the study of a variety of furnace/boiler designs, modes of operation and control options, aimed at reducing the energy consumption for residential space heating. One of the main reasons for the substantial, difference between steady state furnace efficiency and average seasonal system efficiency was found to be caused by the furnace draft flows during the burner off-period. Power burners can reduce the losses, LD, caused by those flows considerably by virtue of functioning like leaky dampers in the off-period. Other reasons for the generally high LD losses are: low average furnace load (oversizing), the use of pilot flame ignition systems, frequent system cycles and high fan/pump control set points. Although typical seasonal efficiency data for gas fired heating systems are about 60%, and 66% for those fired with oil, we estimate that efficiencies of up to 69%, respectively 76%, can be achieved by attending to careful selection, sizing, installation and adjustment.

A high-pressure, high-temperature apparatus for rock deformation

A description is given of a 10 kb 1000°C apparatus for measuring the stress-strain properties of rocks and other materials under high pressure and temperature. Argon is used as pressure medium. Details of the internal furnace and internal load cell are described. An Appendix gives an account of a pressure vessel failure. Apparently originated by corrosion of the bore.

A utility company looks at the electric arc furnace load

A utility company looks at the electric arc furnace load

Some Considerations for the Better Operation of Tank Furnace Based on the Heat Balance in its Melter Basin

The temperature changes in the melting basin of a tank furnace having 43.5 sq. meter of melter area were measured continously and recorded during operation at various points and depths, and some dynamic relations between temperature variations of molten glass and operational variables of furnace were found. The author proposed a equation govering the thermal balance in basin and showed every change of components of this equation with furnace load. With regard to the change of average temperature level of glass in the basin, there is a tendency to shift to the lower side with increasing pull. He also pointed out that the continuous detection of glass temperature in basin can be the most useful mean in keeping the safty operation of furnace under high load. Concerning the mode of main convection current cycle in basin, there are several evidences which prove the single cycle, that is, charging cycle is dominating in stead of double in case the melter is covered over 60% with batch, and also it was found the homogenization of glass takes place chiefly in the area between batch line and bridge wall. Relations between temperature distribution of combustion chamber, melter basin and mode of convection current were discussed and some considerations for the more efficient operation of furnace was made along this line. The performance figure obtained by this furnace is as follows: melting rate: 2.9 ton of glass per sq. meter of melting area, fuel rate: 164 litre of heavy oil per ton of glass produced per day. (ton: metric)

Characteristics of an electric resistance furnace load

IN 1899 Dr. E. G. Acheson discovered that if he overheated silicon carbide, the silicon was volatilized out and pure carbon or graphite remained. Later tests showed that graphite could be manufactured by heating petroleum coke to a high temperature [2,600 C (degrees centigrade)].

A Mechanism for Controlling Several Furnaces Independently with One Temperature Regulator

A simple mechanical device is described in which, by means of a series of cams on a rotating shaft and a hook-and-link mechanism, thermocouples in separate furnaces, in turn, are connected to the temperature controller and switches in the individual furnace load circuits are adjusted either on or off by the reaction of the controller to the e.m.f. of the relevant thermocouple.

A 66-kv 10,000-kva series capacitor for voltage regulation

Light flicker and voltage regulation resulting from an intermittent arc furnace load have been corrected by the largest series capacitor in existence. The design, installation, and protection of this unit presents interesting and unique problems.

Design and Protection of 10,000-Kva Series Capacitor for 66-Kv Transmission Line

To correct for voltage regulation and light flicker on the 66-kv line supplying arc furnace and steel plant load, a series capacitor of 500 amperes continuous rating and 13.5 ohms was installed. This series capacitor was built with three groups of standard 2,400-volt 15-kva capacitor units connected in series per phase with each group being protected by its own by-pass gap and automatic switch. This is the largest and the highest voltage series capacitor so far installed.

A 10,000-Kva Series Capacitor Improves Voltage on 66-Kv Line Supplying Large Electric Furnace Load

Duquesne Light Company placed in service on October 26, 1947, the largest kilovolt-ampere and highest voltage-series capacitor in the world, to improve voltage regulation and alleviate voltage flicker at a large steel mill and on the line serving it. The capacitor has a nominal rating of 10,000-kva and was installed on a 66-kv line. It was built by the Westinghouse Electric Corporation. This paper presents the calculated results of system studies made prior to the authorization of the series capacitor and the reasons for selecting the series capacitor. In addition, the results of staged tests showing the starting of a large induction motor and the energizing of the power transformers at the load with the capacitor in service are included. The improvement in utilization voltage is also shown.