FR2533018A1 - BOILER TYPE DEVICE USING AS A FUEL A SOLID-LIQUID SUSPENSION OF THE CHARCOAL-WATER TYPE - Google Patents

Abstract

1. A boiler type device for the industrial production of thermal fluid such as water vapor, including : - a first combustion zone (5) of stretched cylindrical shape, of length L and diameter D, inclined with respect to the horizontal plane, activated with a rotating motion and equipped with a combustion organ (4). - a second combustion zone (12), distinct from the preceding one, called a solidification zone, of depth P, with I and height H, in which : a) a fraction of the calories contained in the combustion products is transferred by radiation to a receiving panel equipped with cold tubes (13) in which the fluid to be reheated is circulating, and in which b) non combustible particles, melted or dough-like and in suspension in the gaseous current are solidified, with the so-called solidification zone having in its lower part hopper for recovering slag, a third zone (17) for thermal exchange by convection via a tubuar network (18) equipped in its lower part with dust hoppers (21) and connected to the flushing systems (24) for gas and unwatering (25), characterized by the fact that the combustion organ (4) is a multi-fluid burner adapted to burn solid fuel suspended in a liquid, and that in the first combustion zone (5) the fuel is pulverized axially by an auxiliary fluid adapted to the fuel being used, and that the combustion zones shown (5, 12) and the solidification zone are associated via the following geometrical relationships expressed as a function of the parameter D : 3.25 D =< L 3.25 D =< 2.25 D =< I 4. D =< H

Description

The present invention relates to boiler type devices

  allowing the combustion of solfdes-liquids mixtures, for example coal-water and recover the calories produced in the form of hot fluids

under pressure.

  The combustion of coal is usually carried out according to the following main techniques on charcoal grill being then loaded into the combustion chamber in mass that is to say that the coal particles have significant dimensions (of the order

a few centimeters).

  in pulverized form, the coal being finely ground to fine dimensions (a few tens of microns) and

  driven by a spray of air.

  in a fluidized bed, the coal being then ground to

  1 '5 sions of the order-of a few millimeters.

  This last technique, quite recent, may have various variants of embodiment at the type of bed

implemented.

  All these techniques present serious problems

  operating, scrubbing, removal of slag and -

  ash, dedusting, safety devices etc. and often impose significant implementation constraints on the choice of coal, grain size and driving units. Finally, in recent years research and experimentation have begun to study the combustion processes of coal-fuel mixtures and to a degree

  coal-water suspensions are less important.

  the more or less partial substitution of coal for fuel, with the aim of making the most of existing installations for liquid hydrocarbons. The invention relates to devices of the boiler type overcoming most of the disadvantages mentioned above and

allowing including; -

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  to use in the same apparatus a wide range This nature of coal, or even to use any coal and even advantageously the by-products such as fines, dust, slimes etc eliminate almost absolutely security problems

  to best solve the problem of automatic evacuation

tick slags.

  to offer combustion behaviors similar to those of gas and fuel burners and therefore possibilities of operating flexibility similar to those obtained

with these fuels.

  The subject of the present invention is a device for the industrial production of steam or thermal fluid, using as fuel a solid-liquid suspension characterized in that it comprises: a first so-called combustion zone equipped with a multifluid combustion member with axial spraying by fluid

  auxiliary fuel-adapted, of cylindrical form

  elongated dicque, slightly inclined on the horizontal and

  animated by a rotation movement.

  a second zone, completely distinct from the preceding one, said solidification zone of vertical axis in which, on the one hand, a fraction of the calories contained in the products of the combustion is transferred by radiation

  to a receiving wall equipped with cold tubes in the-

  which circulates the fluid to be heated and secondly, the

  non-combustible, melted or pasty particles in

  pension in the gaseous stream are solidified, said area

  of solidification comprising in its lower part a tres-

  a third convective heat exchange zone on a tubular bundle, equipped in its lower part with dust hoppers and connected to the purification system

gas and dewatering.

  The cylindrical combustion zone is equipped with a single multi-fluid type burner attached to the fixed end of the cylinder opposite the solidification zone and whose axis coincides with that of the combustion zone. A pumping system adapted to the fuel used. (solideliquide suspension) serves to introduce said fuel into the burner

  which also receives the auxiliary gaseous fluid of pulveri-

  and combustion air injection of all

  active fluids in the home constituted by the

  combustion is necessarily axial.

  The combustion zone is strongly insulated by means of refractory products forming a radiant hot wall

  held in place by a metal casing.

  The spraying mentioned above is carried out at an effective pressure generally between 0 G, 5 and

2 bars.

  The combustion zone is of elongated cylindrical shape, that is to say that its length (L) will generally be between 3.25 and 5 times the internal diameter (D) of the cylinder, in order to allow a satisfactory evacuation of the scoriae which is generally form in the liquid state in

  this combustion zone, this one will be inclined on the horizontal

  In addition, this zone will be rotated at a slow speed of the order of 1 to 5 revolutions per minute by means of a system.

  conventional roller or chain drive.

  At the exit of this combustion zone is disposed a so-called solidification zone, of vertical axis, distinct from the combustion zone with which it communicates. This solidification zone will have a volume generally between 10 and 15 times the volume of the combustion zone She

  advantageously takes the form of a rectangular parallelepiped

  gle whose depth (P), will be at least equal to (L) length of the combustion zone, a width (1) at least equal to 2.25 D and a height (H) at least equal to 5 D; the solidification zone comprises on its side struts, constituted by a refractory insulating material held in place by a metal casing, cold tubes containing the pressurized fluid to be heated by radiation. In addition, it comprises in its lower part a hopper allowing recover slag from the combustion zone and ash from the solidification zone.

  At the end of the solidification zone is

  perpendicularly a horizontal convection zone equipped with a bundle of exchanger tubes operating by convection, and hoppers to recover the dust present. According to an alternative embodiment of the device of the invention this convection zone may be arranged vertically so that the fumes flow from top to bottom, the essential being that the gas stream is

  subject to a significant change of direction.

  The solid-liquid suspension used as fuel in the device of the invention may for example be a mixture of finely ground coal, that is to say whose particles will generally have a diameter of less than 100 microns and water or any other - appropriate liquid such as

  animal or vegetable oils, alcohols or fuels.

  The content of the liquid mixture is preferably comprised

between 30 and 50 A (weight).

  The device of the invention will be better understood in the light of the embodiment example described below in

reference to Figures 1 and 2.

  Figure 1 shows a schematic longitudinal section

  example of the device according to the invention.

  Figure 2 shows a schematic view of the area

k solidification (12).

  The combustion zone (5) is supplied with solid-liquid suspension via the line (1). The lines (2) and (3) respectively conduct the spray air and

  the combustion air at the multifluid burner (4).

  This burner (4) is arranged on the front wall (6) fixed of the

  zone (5) The walls of this zone consist of

  fractures (7) of a thickness of about 350 mm, held in place by the metal outer casing (8) The zone (5) inclined at an angle <3.5 on the horizontal is rotated at means of a system comprising a motor roller (9) and a support roller (10) on which the

raceways (11).

  The zone (5) opens out on a solidification zone (12) with a vertical axis, in the form of a rectangular parallelepiped. The interior of the walls of the zone (12) is lined with tubes (13) intended for heat exchange by radiation, said walls being formed of an inner insulating refractory lining (14) of about 100 mm thickness held in place by a metal casing (15) In the lower part of the zone (12) is disposed a hopper (16) for recovering slag and ashes The walls of the hopper are constituted in a manner analogous to that of the heat exchange portion of the zone (12). The zone (12) opens out onto a convection zone (17) arranged perpendicular to the zone (12) This zone (17) is equipped with a battery of tubes (18) intended for convective heat exchange o Pipes (19) collect the steam-water emulsion produced by both the tubes (13) ) and the tubes (18) for direct it to the separator tank (20) The zone (17) is equipped at its lower part with hoppers (21) for the recovery of the dust carried by the gas flow and any deposits on the tubes (18), detached by means of A conventional blowing system (not shown) The walls of the zone (17) consist of an insulating refractory (22) having a thickness of about 50 mm.

  held in place by the envelope (23).

  At the exit of the zone (17) the cooled gas stream is sucked by the exhauster (25) through a dust collector

  (24) before discharge to the chimney (26).

  The disoositive of the invention described herein is used in accordance with the process described below with the fuel being a coal-water suspension.

  consisting of a mixture of 40% water and 60% coal.

  This coal was finely milled in an aqueous medium to obtain a particle size centered on 35 microns with a maximum of 100 microns. The viscosity of the mixture is reduced.

  by addition of a surfactant-appropriate product.

  The fuel is introduced by volumetric pumping into the burner, the latter being supplied separately with supercharged compressed air at 0.7 bar effective and combustion air The spray is injected in the axis of the combustion zone whose design allows the total combustion of the coal contained in the suspension within this zone with a combustion rate up to 600 Thermies per m 3 of combustion zone The ignition of the fuel is automatically ensured by the temperature level prevailing in the previously preheated zone at 11000 C with conventional fuel Since the steady state temperature is of the order of 14001 C The thermal load is modulated according to

  requirements by direct action on the volumetric feed pump

  The flexibility thus obtained allows an instantaneous variation of the heat flow in the proportions of 1/5 to 5/5 At the temperatures reached the ashes contained

  in coal are in the liquid state in fine suspen-

  in the combustion gases A fraction of these

  cules is deposited in contact with the refractory walls on which they flow by gravity Their evacuation is ensured by the conjunction of the inclination of the zone on the horizontal and its setting in slow rotation concretions

  potential that may form on the walls are also

  eliminated in the course of their detachment. The latter results in particular from the anti-aera-

the wall vis-à-vis the slag.

  The hot gases (approximately 1400 C) produced in the combustion zone enter the solidification zone. In this zone, the gases are cooled by radiation towards the

  cold walls lined with tubes which causes automatic-

  concomitant cooling of fine particles

  melt ashers transported within the gaseous stream.

  In this zone the temperature of the gas goes from 1400 to about 850 C The hopper located at the bottom of this

  The zone receives, on the one hand, ashes and

  from the combustion zone and, on the other hand, those which could form on the part of the wall opposite

  of combustion, then come off The gases from the area.

  solidification penetrate into the convection zone where they are cooled down to a temperature of approximately 250 ° C. in contact with the bundles of exchanger tubes In this zone, a fraction of the dust is deposited on the tubes from which they are removed by a conventional method -de-, blowing hoppers arranged at the ase receive dust falling

by gravity.

  The water-vapor emulsion generated in the exchange bundles of the solidification and convection zones is collected at the top and directed towards the separator flask.

  The gases coming from the convection zone are dusted off

  res in a conventional way before discharge to the chimney.

  The devices of the invention are particularly advantageous because they allow the use as liquid fuel of coals of all kinds under particularly favorable operating conditions, particularly at the levels of handling, ash extraction,

  flexibility of operation and security.

In addition, it should be noted that

  reading the means of invention it is easy to convert to

  existing boilers, and designed for

  For this purpose, it will suffice essentially to add a combustion zone according to the invention to adapt to the characteristics of the existing boiler. o s 2533018 RLVH Xi DIC-TIOHS

  1 Boiler-type device for industrial production

  trielle of thermal fluid such as -the water vapor using as fuel a solid suspended in a liquid characterized in that it comprises: a first combustion zone (5) equipped with a multifluid combustion member (4) with axial spray by auxiliary fluid adapted to the fuel used, elongated cylindrical shape, slightly inclined to the horizontal and driven by a rotational movement, a second zone (12), distinct from the previous, said solidification zone in which on the one hand, a fraction of the calories contained in the products of the combustion is transferred by radiation to a receiving wall equipped with cold tubes (13) in which circulates the fluid to be heated, and on the other hand non-combustible particles, melted suspended in the gaseous stream are solidified, said solidification zone comprising in its lower part a hopper (16) for recovering the slag and,

  a third zone (17) for heat exchange by convection

  tubular bundles (18) equipped in its lower part with a dust hopper (21) and connected to

  gas purification systems (24) and dewatering systems (25).

  2 Device according to claim 1 characterized in that the combustion zone (5) is inclined on the horizontal

an angle between 2 and 8 -

  3 Device according to one of claims 1 and 2 character-

  in that the combustion zone (5) is

  rotation at a speed between 1 and 5 revolutions / min.

  4 Device according to claim 1, characterized in that the dimensions of the combustion zone (5) are connected by the following relationship: L> y 3.25 D.

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  Device according to Claim 4, characterized in that the dimensions of the combustion zone (5) and of the solidification zone (12) are connected by the following geometrical relations:

P 3.25 D

1 2.25 D

H 5 D