US4228747A High energy arc ignition of pulverized coal

An electrical discharge is controlled in such a manner as to permit its use to reliably ignite a fuel stream consisting of pulverized coal entrained in air. The ignition technique of the present invention creates expanding and contracting plasma pockets at a rate which is high compared to the velocity of the fuel stream and permits the ignition of the fuel stream in a cold furnace and/or

High energy arc ignition of pulverized coal Combustion

The present invention overcomes the above-discussed dificiencies and disadvantages of the prior art by providing for the "direct" ignition of a stream of pulverized coal and air in a "cold" environment through the use of only a high energy electrical arc as an ignition energy source.

Plasma Technology for Enhancement of Pulverized Coal

pulverized coal burner equipped with arc plasmatron. The base of the PFS Further mixing with the air promotes intensive ignition and complete combustion the fuel mixture is heated, volatile components of coal arc extracted, and carbon is partially gasified. This active blended fuel can ignite the

Induction-heating ignition of pulverized coal stream

Nov 01, 2004 Induction-heating ignition burner for the pulverized coal fired boiler is introduced. Some experiments were conducted on an experimental set-up, which includes alternative current power system, induction-heating system, pulverized coal and air supplier system, and measurement system to study the ignition process of coal powder and air mixture stream.

CN2591434Y High-temperature air ignitor for pulverized

The utility model relates to a high-temperature air ignitor for a pulverized coal fired boiler, which belongs to the technical field of an auxiliary machine of a boiler. An oil injection method is generally used by the pulverized coal fired boiler to carry out ignition to cause a large quantity of fuel oil to be consumed. In order to save the oil, the ignitor of the utility model which is

Numerical simulation of ignition in pulverized coal

Feb 15, 2017 In order to enhance the ignition, coal particles in the central region of −1.0 mm < y < 0 mm are initially heated up to 2000 K without giving any other heat sources. The reasons to employ this condition are that firstly, to avoid that shear vortices in the central region tended to achieve to the side boundaries before the ignition occurs.

Laser ignition and flame propagation of pulverized coal

Jan 01, 1996 Ignition and combustion behaviors were examined for uniformly sized, pulverized coal dust clouds that were suspended in a laminar upward flow and heated by a single-pulsed YAG laser. Effects of coal type, particle diameter, and oxygen concentration on lean limit of flame propagation and flame propagation velocity for hv and lv bituminous coals

Plasma Arc Burner for Pulverized Coal Combustion

arc acts directly on pulverized coal-air mixture is simple. This should allow a significant improvement of pulverized coal combustion (especially low-quality coal) and its economic efficiency. Preliminary experiments demonstrated the successful functioning of the system. Keywords—Coal combustion, plasma arc, plasma torches, pulverized coal. I.

Laser Ignition of Pulverized Coals Cal Poly

to examine pulvcrized-coal ignition. Most arc described in the review by Essenhigh et al. (21­ The ignition behavior of clouds of pulverized fuel is of greatest interest to those concerned with the prevention of dust explosions (in coal mines or grain elevators, for example) and with flame stabiliry in coal-fired combustors (3-5].

Numerical simulation of ignition in pulverized coal

Feb 15, 2017 The mono-dispersed pulverized coal particle-laden flow in a two-dimensional mixing layer is targeted. Fig. 1 shows the schematic diagrams of the computational domain and boundary conditions, and Table 3 shows the initial flow and coal particles conditions. The diameter of 25 μ m, which is relatively smaller than that used in actual coal combustion furnaces, is chosen in order to enhance

Ignition temperature of pulverized coal particles

The ignition characteristics of a cloud of pulverized coal flowing in a drop-tube furnace are examined. Cloud ignition is defined at the minimum gas temperature at which significant oxygen consumption occurs. This is accompanied by the generation of carbon dioxide and oxides of nitrogen, and the formation of a visual flame.

LABORATORY AND INDUSTRIAL STUDIES OF GAS COAL

One of the modern technologies is the use of a direct current plasmatron for ignition and stabilization of the pulverized coal flame [9]. This technology is based on heating the flow of a pulverized-coal mixture by a high temperature plasma arc at oxygen deficiency to the tem-perature exceeding the self-ignition temperature of this coal [10].

Ignition and Combustion of Pulverized Coal and Biomass

This work studied the ignition and combustion of burning pulverized coals and biomasses particles under either conventional combustion in air or oxy-fuel combustion conditions. Oxy-fuel combustion is a 'clean-coal' process that takes place in O2/CO2 environments, which are achieved by removing nitrogen from the intake gases and recirculating large amounts of flue gases to the boiler.

Fire and Explosion Prevention in Coal Pulverizing Systems

long as the coal/ air mixture can be considered a cloud. In practice, a fire occurring during normal pulverizer operation does not result in an explosion. The rich coal/ air mixture has been shown to absorb the heat of the ignition source without igniting, and therefore it often produces no deflagration. The fire can be extinguished

Latest Low-NOx Combustion Technology for Pulverized

the pulverized coal in the region of hot gas that is retained in the recirculation zone enhances ignition. (2) Concentration of pulverized coal The concentration of the pulverized coal is a critical factor in enhancing ignition. The denser the pulverized coal, the shorter the distance between coal particles. This promotes rapid ignition and flame

Advanced Development of Pulverized Coal Firing Technologies

This type of burner features a ring-shaped pulverized coal nozzle to assure ignition stability and burnout and supplies combustion air from both outside and inside the pulverized coal flow in order to efficiently mix the very highly concentrated pulverized coal flow, which is blown into the furnace, with the combustion air. Figure 3 shows

(PDF) Plasma-Supported Coal Combustion in Boiler Furnace

ignition of the air/coal mixture and subsequent displacement. pulverized coal fuel in the electric arc devices,” Thermophys. Aerome- radiative heat transfer in a pulverized coal flame

Plasma Torch for Plasma Ignition and Combustion of Coal

Plasma-fuel systems (PFS) have been developed to improve coal combustion efficiency. PFS is a pulverized coal burner equipped with arc plasma torch producing high temperature air stream of 4000 6000 K. Plasma activation of coal at the PFS increases the coal reactivity and provides more effective ignition and ecologically friendly incineration of low-rank coal.

Plasma ignition of dust-coal flame

of a pulverized coal flame. However, carrying out full-scale tests of PFS, which are complex heat and electrotechnical systems, is characterized by high cost and labor costs, despite their external simplicity. The technology of PTPСB consists in heating the fuel mixture (coal dust + air) by electric arc

Use of cavity plasmatron in pulverized coal muffle burner

A flow of the remaining pulverized coal burners are started circumferential air in a plasma channel causes circular gradually after reaching the required thermal movement, which aims to push out the electric arc parameters of the furnace and other elements of the from gap between the cathode and anode and extend boiler.

US4690075A Ignition and combustion supporting burner for

An ignition and combustion supporting burner for pulverized solid fossil fuel comprises an axial conduit for feeding the pulverized fuel in a primary combustion supporting gas. The shape of a refractory tap-hole enables the initial part of the flame to be confined. A conduit for feeding tertiary combustion supporting gas is concentric with the tap-hole and partially or totally surrounds it.

Plasma Arc Burner for Pulverized Coal Combustion

arc acts directly on pulverized coal-air mixture is simple. This should allow a significant improvement of pulverized coal combustion (especially low-quality coal) and its economic efficiency. Preliminary experiments demonstrated the successful functioning of the system. Keywords—Coal combustion, plasma arc, plasma torches, pulverized coal. I.

Plasma Arc Burner for Pulverized Coal Combustion

Development of new highly efficient plasma arc combustion system of pulverized coal is presented. As it is well-known, coal is one of the main energy carriers by means of which electric and heat energy is produced in thermal power stations. The quality of the extracted coal decreases very rapidly.

Modeling of Coal Ignition in Plasma-Fuel Systems With an

Dec 20, 2019 Modeling of Coal Ignition in Plasma-Fuel Systems With an Electric Arc Torch Abstract: Results of numerical experiments on ignition of pulverized coal in a plasma-fuel system (PFS) are presented. PFS is designed for fuel oil-free startup of the boilers and stabilization of pulverized coal flame and represents a pulverized coal burner equipped

Mathematical simulation of ignition of a coal-dust

Abstract. The process of aerosuspension ignition of a suspension in air in a pulverized-coal burner with a preswitched muffle by a central axisymmetric air stream heated in an electric-arc plasmatron to a temperature of about ≈5000K is numerically simulated. This process is the basis of a new fuel-oil-free method of ignition of the boilers of thermal power stations.

Ignition temperature of pulverized coal particles

The ignition characteristics of a cloud of pulverized coal flowing in a drop-tube furnace are examined. Cloud ignition is defined at the minimum gas temperature at which significant oxygen consumption occurs. This is accompanied by the generation of carbon dioxide and oxides of nitrogen, and the formation of a visual flame.

Plasma ignition of dust-coal flame

of a pulverized coal flame. However, carrying out full-scale tests of PFS, which are complex heat and electrotechnical systems, is characterized by high cost and labor costs, despite their external simplicity. The technology of PTPСB consists in heating the fuel mixture (coal dust + air) by electric arc

Ignition and Combustion of Pulverized Coal and Biomass

This work studied the ignition and combustion of burning pulverized coals and biomasses particles under either conventional combustion in air or oxy-fuel combustion conditions. Oxy-fuel combustion is a 'clean-coal' process that takes place in O2/CO2 environments, which are achieved by removing nitrogen from the intake gases and recirculating large amounts of flue gases to the boiler.

Latest Low-NOx Combustion Technology for Pulverized

the pulverized coal in the region of hot gas that is retained in the recirculation zone enhances ignition. (2) Concentration of pulverized coal The concentration of the pulverized coal is a critical factor in enhancing ignition. The denser the pulverized coal, the shorter the distance between coal particles. This promotes rapid ignition and flame

Fire and Explosion Prevention in Coal Pulverizing Systems

long as the coal/ air mixture can be considered a cloud. In practice, a fire occurring during normal pulverizer operation does not result in an explosion. The rich coal/ air mixture has been shown to absorb the heat of the ignition source without igniting, and therefore it often produces no deflagration. The fire can be extinguished

Advanced Development of Pulverized Coal Firing Technologies

This type of burner features a ring-shaped pulverized coal nozzle to assure ignition stability and burnout and supplies combustion air from both outside and inside the pulverized coal flow in order to efficiently mix the very highly concentrated pulverized coal flow, which is blown into the furnace, with the combustion air. Figure 3 shows

Coal Pulverization System: Explosion Prevention and

Pulverized coal enters the rotating dryer and goes through the dryer while the dryer is rotating. There are crooked steam pipes inside the rotating dryer serving as heat exchanger. The temperature inside the dryer is 135°C. The heated air inside the dryer brings away the vapor extracted from coal particles.

NUMERICAL RESEARCH OF HEAT AND MASS TRANSFER

cal accidents in thermal power plants, related to pulverized coal ignition, more detailed repre-sentations of patterns and characteristics of heat and mass transfer processes at low-temperature (T < 500 K) coal particle ignition are required. The purpose of present work is the mathematical simulation of heat

Development of Co-Firing Method of Pulverized Coal and

used for the pulverized coal/ammonia co-firing test(3). The combustion test furnace has one burner at the front. Air supplied from the Forced Draft Fan (FDF) undergoes heat exchange with the flue gas in the Gas-Air-Heater (GAH), which recovers heat from boiler flue gas and heats combustion air using the recovered heat to promote

2013 Hitachi Latest Technology for Coal Firing Power Plants

secondary air jets to the outside along the Baffle Plate, which is equipped on the Flame Stabilizing Ring. As hot gas stagnates in the recirculation zone, pulverized coal is rapidly heated and this enhances ignition. (2) Concentration of pulverized coal Concentration of pulverized coal is pivotal to ignition