Auxiliary Fuels Research Articles

99/01536 Manufacture of pig iron with injection of fuels and other materials through blast-furnace tuyeres. Part I. Characteristics of auxiliary fuels and their effect on the blast-furnace process : Garcia, L. et al. Rev. Metal., 1998, 34, (1), 51–59. (In Spanish)

The integrated-gasification-combined-cycle (IGCC) system has been proposed as one of the energy-producting technologies that can assist in reducing the emission of carbon dioxide, CO2, while still providing a high electric efficiency.With these arguments as a basis, A. Ahlstrom Corporation of Finland and Sydkraft AB of Sweden decided to develop jointly the Bioflow Energy System based on IGCC technology and utilizing biomass as fuel. An essential part of this co-operation is the construction of a demonstration plant in the city of Värnamo in southern Sweden. This plant, which will generate 6 MW of electricity and 9 MW of district heating, is based on circulating fluidized-bed technology. Plant commissioning started in the spring of 1993.The biomass-based IGCC technology, the Värnamo demonstration plant, and other development work are discussed in this paper.

99/00676 Manufacture of plg iron with injection of fuels and other materials through blast-furnace tuyeres Part I. Characteristics of auxiliary fuels and their effect on the blast-furnace process

99/00676 Manufacture of plg iron with injection of fuels and other materials through blast-furnace tuyeres Part I. Characteristics of auxiliary fuels and their effect on the blast-furnace process

Effect of Dimethyl Ether Synthesis on Methanol- and Iron-making Integrated System.

In a previous study the catalysts for synthesizing dimethyl ether ((CH 3 ) 2 O, DME) from blast furnace gas were successfully developed for increasing methanol (CH 3 OH, MeOH) yield. The objective of this study is to design a new MeOH-Iron production system through DME synthesis based on the results, to evaluate a system from exergy concept and to compare with a previously proposed MeOH-Iron production system. Then, effect of the systematic combination and auxiliary fuel injections to a blast furnace on exergy consumption in the system was mainly assessed. As a result, the exergy consumption of the new system for hot-metal production became 10% lower than the previous one. At the same time, its exergy consumption for MeOH production decreased as much as 36% of the previous one, showing thermodynamic advantage of DME synthesis. The amount of MeOH production had great dependence on a kind of auxiliary fuels through top gas composition of a blast furnace (BF). It was concluded that MeOH production with DME synthesis and the injection of COM or PC to BF was best systematic combination for maximizing MeOH production from BF offgas.

Fluidized-bed incineration of solid pellets: Combustion and co-combustion

The UIC experimental facility for combustion of materials in a fluidized-bed combustor is described. The combustion and co-combustion studies made in a heated inert bed, of wood, refuse-derived fuel, peanut-hull, paper, cellulose and cardboard pellets are reviewed and discussed. Coal and propane are used as auxiliary fuels. The investigations cover a range of gas velocities, combustion temperatures, fractional excess air values and solid pellet feed rates. The emission of carbon monoxide in the flue gas is monitored, and for most conditions, its value is well within the limit set by the Illinois Environmental Protection Agency. The carbon combustion efficiency values are found to be quite high, 99.8 + percent, validating the thermal degradation capability of the fluidized-bed incinerator. Further, the thermal combustion efficiencies are also equally high, which reinforces the concept of waste to energy generation.

Lift-Off Stability of n-Heptane Jet Diffusion Flames in Homogeneous Environments of Fuel and Air

The lift-off of jet diffusion flames of a liquid fuel in coflowing streams of air was established experimentally for a range of jet discharge and stream velocities. The improvement in the lift-off stability of the flame due to the presence of a small concentration of an auxiliary gaseous fuel in the surrounding air was established. Liquid n-heptane was the jet fuel while methane, ethylene, propane, and hydrogen were employed individually in small concentrations as the auxiliary fuels. It is shown that the lift-off distance and the corresponding ignition delay of the jet flame can be correlated for all the observations made in terms of derived dimensionless grouping of the main parameters varied, which included the jet discharge velocity, the surrounding stream velocity, and the concentration of the fuel added to the surroundings of the flame.

Integrated Mathematical Model of Pulverised Coal Combustion in a Blast Furnance.

The shortage of coke production due to the closure of coke ovens has led in Japan and other industrialised countries to increasing the injection of auxiliary fuels, e.g. pulverised coal (PC) into blast furnace tuyeres. The PC injection at high rates of more than 200 kg/t requires high burnout within the raceway zone. In order to analyse flow and combustion in the raceway and to assist improvement of burner design, a two-dimensional mathematical model of PC combustion has been developed with simulating both the blowpipe and raceway. Effects of a packed bed on the turbulent features of gas and particulate flow were introduced to the model along with all other pertinent phenomena such as heterogeneous reactions of coke and char particles. Validation work against measurements in two industrial blast furnaces indicated that the model has worked satisfactorily for simulation with and without PC injection. Various measures for burnout improvements were explored under an injection rate of 200 kg/tHM. Notable improvements were observed by oxygen enrichment to the secondary air and enlargement of the outer diameter of the injection burner.

A Numerical Study of the Unsteady Effects of Droplet Evaporation and Ignition in Homogeneous Environments of Fuel and Air

The transient processes of droplet heating, vaporization and ignition in a quiescent heated environment of a homogeneous mixture of air and fuel that is potentially combustible are analyzed. A system of partial differential equations that governs this hybrid diffusional-premixed processes is presented. The equations were solved numerically for an n-heptane droplet vaporizing in a homogeneous environment of methane and air. The effective reaction rate of the oxidation processes was assumed throughout to equal the sum of the reaction rates due to droplet and auxiliary fuels. The gross reaction rates used in the model for the droplet and auxiliary fuels were obtained from curve fitting of reaction rates results obtained from detailed chemical kinetics for the two fuels system. It is to be shown, for example, that the presence of an auxiliary fuel with the air in the surrounding environment of the droplet enhances the rates of the ignition/combustion processes of the droplet.

Heat and mass balance analysis of an incinerator for aqueous wastes

We present an analysis of incinerators for 100% aqueous wastes in which an energy balance is performed for a general C mH nO pS qN r type auxiliary fuel. General equations relating design temperatures and residence times to wastes/fuel ratios and excess air are developed. The methodology is applied to the use of oil or natural gas as auxiliary fuels.

Waste combustion

Waste materials are generated by every activity of modern industrial society. Combustion or thermal treatment can be a viable disposal technique for many of these waste streams because it can destroy hazardous organics and pathogens, and can significantly reduce mass and volume. The waste streams that are commonly burned include refuse from municipalities, medical and infectious waste from medical institutions, sludges from municipal sewage treatment, hazardous waste streams from industrial processes, and materials from the cleanup of abandoned landfill sites. The combustion systems used for these different waste streams are widely divergent because of the different physical characteristics of the materials. The state of the art in combustion systems that is discussed include liquid injection incineration systems for pumpable liquids, rotary kilns, reciprocating grate stokers, controlled air fixed hearths, and multiple hearths for unprocessed solids, and spreader stokers and fluidized beds for processed fuels from waste. In addition there is a wide range of industrial furnaces and boilers where waste streams are cofired with auxiliary fuels. The key challenges to waste combustion in the future are the optimization of the total combustion system to reliably burn wastes while minimizing emissions of all pollutants into any effluent stream (solid, liquid or air) and the development of performance assurance techniques to continually monitor the system. The ability to design, operate and monitor a waste combustion, system to assure the optimized control of all emissions requires detailed knowledge of physical and chemical processes taking place within the waste combustion system and the chemistry of formation and control of these pollutant species. The current state of the knowledge regarding the formation and control of these species in waste combustion systems has resulted in significant reductions in emissions; however significant data gaps exist that preclude further advances. These data gaps must be filled with basic engineering research and vertically integrated assessment and system development studies. This paper characterizes current combustible waste streams and control of important emissions species from full scale equipment, and suggests future directions for research which could lead to the next generation of waste combustion equipment.

The Economic Feasibility of Crop Residues as Auxiliary Fuel in Coal‐Fired Power Plants

AbstractRising fossil fuel costs spark interest in crop residues as a renewable energy source. Residue costs for combustion in power plants are estimated in 1975 prices to evaluate their feasibility. Costs are estimated for farm production, transportation, and processing and handling at the energy recovery level. They are incorporated into an Iowa agricultural programming model which includes an electric utility sector. The model, including crop production, is solved for several scenarios—a base solution, energy price increases, and a sulfur constraint. Under these scenarios, crop residue replaces coal at 20%,40%, and 60% of the 1975 Btu's consumed.

Solar Energy and Electric Utilities: Should They Be Interfaced?

Analyses of the economics of solar collection in the firm- and shifting-peak cases (that is, with off-peak electricity indefinitely available or with a flat load curve) indicate that, for many important applications, solar energy systems that interface with electric utilities can be justified only in terms of the value of the off-peak utility fuels that they displace. In regions where off-peak electricity costs are low, the most economically efficient solar energy systems will be those that use electricity as the auxiliary energy source. This implies extremely low break-even costs for a number of important solar energy applications. In regions where the cost of off-peak electricity is higher than that of competing energy forms, the most economical solar energy systems will utilize auxiliary fuels other than electricity. The general conclusion is that conventional electric utility systems and most solar energy systems represent a poor technological match. The basic problem is that both technologies are very capital intensive. The electric utility, because of the high fixed costs of generation, transmission, and distribution capacity, represents a poor backup for solar energy systems. On the other hand, the solar collection system, because it represents pure, high-cost capital and because of its outage problems, cannot be considered as a part-load source of auxiliary energy for the electric utility system.

The Inzection of Pulverized-coal into the Blast Furnace

As one of the methods for reducing the blast furnace coke rate, there is the technique of injection auxiliary fuels from the tuyers.Operating problems have been encountered when injecting coal as an auxiliary blast furnace fuel. These must be overcome before coal injection will receive widespred application.It is possible by such a simple measure as imprving the fuel oil injection equipment somewhat to obtain a slurry injection of 30wt% coal concentration; but at such a high concentration as 50wt%, the burner is liable to be clogged. It is thus necessary to contrive the injection equipment in such a way as to make the injection volumes even for all the tuyeres. By completing such an equipmene, we have been injected slurry of 50wt% coal concentration with satisfactory results.

An Evaluation of the Effect of Auxiliary Fuel Addition to Intake Air on the Performances of a Diesel Engine with Various Prechambers

An Evaluation of the Effect of Auxiliary Fuel Addition to Intake Air on the Performances of a Diesel Engine with Various Prechambers

Blast Furnace Practice of Tomorrow

A survey of techniques being used to increase the blast-furnace potential. The future will witness universal utilization of better burdens, high blast- temperatures, auxiliary fuels, high top-pressures, oxygen enrichment, and high wind-rates.

The Effect of Auxiliary Fuels on the Smoke-limited Power Output of Diesel Engines

It is well known that one of the factors Limiting the power output from Diesel engines is the tendency to produce exhaust smoke. In consequence only some 65–70 per cent of the available air can be burnt. By reducing the full-load quantity of Diesel fuel injected and aspirating a volatile fuel, such as gasoline, into the intake air, power outputs of 20 per cent or more above the maximum rated load can be obtained without producing more smoke than when the engine is operated at full load under normal conditions. About 80 per cent of the available air can then be utilized. The effect of octane number of the auxiliary fuel is important, maximum smoke-limited powers being obtained with the higher octane number fuels, while with fuels of low octane number, power increase may be limited by the occurrence of knocking when the air-fuel ratio is too low. By limiting the power on Diesel fuel alone to about 80 per cent of the normal maximum and aspirating gasoline into the intake, it is possible to obtain a power increase of about 12 per cent at all speeds between that of maximum torque and maximum power without increased smoking or the occurrence of knock. Owing to improved economy, the fuel cost per brake horsepower per hour using gasoline aspiration, is not increased. Modifications required to the engine are slight and the fuels required to operate are readily obtainable; even if the auxiliary fuel should run out no damage would be done to the engine.