Device and facility for converting dry carbon-containing and/or hydrocarbon-containing raw materials into synthesis gas

Abstract

The invention relates to a device (100) for converting carbonaceous dry raw materials (MPCS) into a synthesis gas, comprising a MPCS pyrolysis chamber (110); a port (106) for introducing the MPCS into said pyrolysis chamber (110); and a port (108) for extraction of synthesis gas from said pyrolysis chamber (110). The device (100) further includes a central chamber (120) immersed in said pyrolysis chamber (110) and comprising a port (128) allowing only a gaseous communication between said central chamber (120) and said pyrolysis chamber (110); and an oxygen injection port (132) in said central chamber (120) for oxidizing at least one portion of the pyrolysis gases passing from the pyrolysis chamber (110) to the central chamber (120).

Claims

1. A device (100) for converting carbonaceous dry raw materials (MPCS) into a synthesis gas comprising CO and H2, said device (100) comprising: a MPCS pyrolysis chamber (110) open at the top and bottom, and adapted to contain MPCS; a port (106), at top of said pyrolysis chamber, for introducing the MPCS into said pyrolysis chamber (110); and a port (108) for extraction of synthesis gas from said pyrolysis chamber (110); a central chamber (120) disposed in said pyrolysis chamber (110), and comprising: at least one port (128) allowing only a gaseous communication between said central chamber (120) and said pyrolysis chamber (110); and at least one oxygen injection port (132) in said central chamber (120) for oxidizing at least one portion of the pyrolysis gases passing from the pyrolysis chamber (110) to the central chamber (120); wherein: at least one oxygen injection port (132) is in a cracking chamber at the bottom of said central chamber (120); and the gaseous communication ports (128) are at the top and on the sides of said central chamber (120), wherein said device comprises at least one double wall (124) separating the central chamber (120) from the pyrolysis chamber (110), intended to circulate a gaseous flow of CO2, wherein on an opposite side to the central chamber (120) the pyrolysis chamber (110) is delimited by a further double wall (112) on at least one lateral portion of said pyrolysis chamber (110), and wherein the at least one double wall (124) separating the pyrolysis chamber (110) and the central chamber (120), and the further double wall (112) delimiting the pyrolysis chamber (110), communicate with each another through one or more transverse double walls (126), wherein said device is in the form of a one-piece assembly.

2. Device (100) according to claim 1, wherein said device comprises in the central chamber (120) a heat source providing the heat necessary for starting said device (100).

3. Device (100) according to claim 1, wherein the central chamber (120) and the pyrolysis chamber (110) are concentric.

4. Device (100) according to claim 1, wherein said device comprises at least one grill (114) for introducing a gaseous flow of CO2.

5. Device (100) according to claim 1, wherein said device comprises at least a hole (134) for introducing CO2 into at least one of said at least one, of said further, and of said transverse double wall (112, 124, 126).

6. Facility (400) for producing a synthesis gas comprising CO and H2, from carbonaceous dry raw materials (MPCS), wherein said facility (400) comprises: a device (100) according to claim 1; means (402) for introduction of MPCS in said conversion device (100); and means (406) for extraction of synthesis gas provided by said conversion device (100).

7. Facility (400) according to claim 6, wherein the extraction means (406) comprises at least one of the following means: at least one means (414) for aspiration of synthesis gas connected to the extraction port (108) of the conversion device (100); at least one heat exchanger (408, 412) for cooling the synthesis gas supplied from said conversion device (100); and at least one device (410) for filtration of synthesis gas provided by said conversion device (100).

Description

DESCRIPTION OF DRAWINGS AND EMBODIMENTS

(1) Other advantages and features will appear by examining the detailed description of a non-limiting embodiment and accompanying drawings, in which:

(2) FIG. 1 is a schematic vertical section view of a non-limiting exemplary embodiment of a conversion device according to the invention;

(3) FIG. 2 is a schematic top view of the device in FIG. 1;

(4) FIG. 3 is a schematic horizontal section view of the device in FIG. 1; and

(5) FIG. 4 is a schematic view of a non-limiting exemplary embodiment of a facility according to the invention.

(6) It should be understood that the embodiments described below are not limiting in any way. In particular, it will be possible to imagine variants of the invention comprising only a selection of characteristics described subsequently isolated from other characteristics described, if this selection of characteristics is sufficient to confer a technical advantage or to differentiate the invention from the prior art. This selection comprises at least one feature preferably functional without structural details, or having only a portion of the structural details if this portion alone is sufficient to confer a technical advantage or to differentiate the invention from the state of the prior art.

(7) In the drawings, the elements common to several figures retain the same reference.

(8) FIGS. 1-3 are schematic views of a non-limiting exemplary embodiment of a device according to the invention for conversion of MPCS into synthesis gas.

(9) FIG. 1 is a vertical section view of the device, FIG. 2 is a top view and FIG. 3 is a horizontal sectional view along line A-A in FIG. 1.

(10) The conversion device 100 shown in FIGS. 1-3 is in the form of a vertical cylindrical one-piece assembly formed of a side wall 102 and a bottom wall 104.

(11) The device 100 comprises a port 106 for introduction of MPCS at its upper end and a port 108 for extracting synthesis gas at its bottom.

(12) The device 100 further comprises a MPCS pyrolysis chamber 110 extending substantially along the entire height of the conversion device 100.

(13) The pyrolysis chamber 110 is open at the top along the entire width of the introduction port 106, for pouring the MPCS to be treated.

(14) In the pyrolysis chamber 110 the MPCS move downward due to gravity.

(15) The synthesis gases generated in the pyrolysis chamber 110 also move downward because they are evacuated, for example by aspiration, through the extraction port 108 located at the bottom of the device 100.

(16) In the central portion of the device 100, along the vertical axis, the pyrolysis chamber 110 is separated from the outer side wall 102 of the device 100 by a double wall 112. This double wall is designed to circulate a gaseous flow of CO.sub.2 to heat it.

(17) In addition, the pyrolysis chamber 110 comprises, at the top, hot CO.sub.2 injection grills 114 formed in the double wall 112, so that the gaseous flow of heated CO.sub.2 is introduced in the top of the pyrolysis chamber.

(18) In its lower section, the width of the pyrolysis chamber 110 decreases so that the bottom of said pyrolysis chamber 110 forms a funnel. This funnel is open on the side of the extraction port 108, and the latter is located above the bottom level of the funnel. Thus, the non-gasifiable solid residues released during the pyrolysis of MPCS can not exit through the synthesis gas extraction port 108.

(19) Under the funnel, that is, under the pyrolysis chamber 110, a grill 116 and an ashtray 118 are provided for evacuation of non-gasifiable solid residues.

(20) The device 100 further comprises a central chamber 120 shaped like a vertical column. The central chamber 120 is disposed in the pyrolysis chamber 110 and is completely surrounded by the pyrolysis chamber above, below and on the sides. In other words, the central chamber 120 is completely embedded or immersed in the pyrolysis chamber 110.

(21) The central chamber 120 is separated from the pyrolysis chamber 110.

(22) At the top the central chamber 120 has a single wall 122 forming a cap shaped like a cone or a pyramid, so as to direct the MPCS in the pyrolysis chamber located around the central chamber 120.

(23) On the sides, the central chamber 120 is separated from the pyrolysis chamber by a double wall 124, provided for circulating a gaseous flow of CO.sub.2 in order to heat it. This double wall 124 is in communication with the double wall 112 through tubular transverse connections 126 that connect them together. The circulation occurs from the top of the double wall 124 of the central chamber 120 to the top of the double wall 112 of the pyrolysis chamber 110, and from the base of the double wall 112 of the pyrolysis chamber 110 to the base of the double wall 124 of the central chamber 120. This configuration allows the natural circulation of CO.sub.2 in this assembly due the “thermosiphon effect” generated and controlled by the high heat (temperature rise to above 1,200° C. in the conditions explained hereinafter) generated in the cracking chamber and the heat exchange, through conduction and radiation, by the inner wall of the double wall 124 of the central chamber 120, generating an upward flow of CO.sub.2 contained in this double wall and which expands on heating. Said CO.sub.2 circulating in said double walls 124 and 112 cools by heat exchange with the MPCS, through conduction and radiation, and it densifies by imposing a downward flow in the double wall 112 of the pyrolysis chamber 110. These inverted flows cause a natural thermodynamics circulation of said CO.sub.2 through “thermosiphon effect” generated and controlled by oxy-combustion of a fraction of the pyrolysis gas generated in the cracking chamber.

(24) The walls 122 and 124 comprise gaseous communication ports 128 allowing only passage of gas between the central chamber 120 and the pyrolysis chamber 110. Thus, the high temperature gas (above 1,200° C.) produced in the central chamber 120 can pass into the pyrolysis chamber 110 for example through the double side wall 124 or the cap 122.

(25) The central chamber 120 comprises on the bottom a chamber 130, so-called cracking chamber, which forms the lower section of the central chamber 120. At the top said chamber 130 is open to the remaining of the central chamber 120, and at the bottom it is open to the pyrolysis chamber 110. The side wall of the cracking chamber is sealed.

(26) Said cracking chamber 130 has at its lower end an oxygen injector 132 for oxidize a portion of the pyrolysis gases contained therein, which originate from the pyrolysis chamber 110 in the periphery of the base of the cracking chamber 130, as explained below.

(27) The oxy-combustion of the pyrolysis gases in the cracking chamber 130 is very exothermic. On the one hand, this exothermic process generates thermal energy that supplies the energy requirement of the device 100 for the conversion of the MPCS into synthesis gas. On the other hand, the exothermic oxy-combustion in the cracking chamber 130 generates a strong expansion of the gas, which is heated to above 1,200° C. and is contained by the walls of the cracking chambers 130 and the central chamber 120. Such expansion creates an exponential overpressure in the central chamber 120, the excess of which is evacuated by powerful jets of hot gases through the outlet ports 128. This overpressure and these evacuation jets generate an upward flow of the gas flows in the pyrolysis chamber 120, opposite to the downward flow of the pyrolysis chamber 130. The upward flow combined with the overpressure allows the gaseous flow at a temperature above 1,200° C. to penetrate all the MPCS present in the pyrolysis chamber 110 through the walls 124 and 122. These outlets favor and accelerate the upward thermodynamic flow, which creates a relative vacuum at the periphery of the base of the cracking chamber 130, in the interconnection with the pyrolysis chamber 110. This generates an aspiration in this passage zone of the pyrolysis gases (CO and H.sub.2), which are in downward movement aspired by the extraction system described below. The equivalent relative to the gases expelled by the outlet ports 128 is aspired into said cracking chamber 130, where a fraction of these pyrolysis gases is oxidized by the oxygen introduced through the injector 132. Said oxygen injection is drastically controlled by the control of temperature inside the central chamber 120 (through a probe already known, not described), wherein oxidation of a fraction of the pyrolysis gases aspired into the cracking chamber 130 raise the temperature of all of said pyrolysis gases (aspired at the interconnection of the periphery of the base of the cracking chamber 130 with the pyrolysis chamber 110) to above 1,200° C., which contributes to the upward thermodynamic flow and the overpressure and expulsion of hot gases to the pyrolysis chamber 110. Such thermodynamic movement with opposing vertical circular flows (upward/downward) along the entire periphery of the central column (composed of the central chamber 120 and the cracking chamber 130) is known as “natural thermosiphon effect”. The gaseous assembly above 1,200° C., which is propelled into the centre of the MPCS in the entire volume of the pyrolysis chamber 110, is essentially composed of CO and H.sub.2 of said pyrolysis gases (aspired into the interconnection of the periphery of the base of the cracking chamber 130 with the pyrolysis chamber 110) and molecules of CO.sub.2 and H.sub.2O from the oxy-combustion of the fraction of said pyrolysis gases (aspired into the cracking chamber 130), whose exothermic oxidation by oxygen from the injector 132 allows said gaseous assembly to reach above 1,200° C., depending on the desired pyrolysis kinetics. The thermodynamic cycle with thermosiphon effect, autogenous and permanent, continuously recycles a portion of pyrolysis gas which becomes the main heat carrier agent that provides the thermal energy necessary for the pyrolysis of all the MPCS present in the pyrolysis chamber 110, before being extracted as synthesis gas via the port 108. The overpressure (controlled by the temperature of the middle of the central chamber 110) is defined higher than the inertia of the MPCS present in the funnel of the pyrolysis chamber 110 (under the cracking chamber 130), which has an effect of allowing partial evacuation of superheated pyrolysis gases from said cracking chamber. This fraction of the pyrolysis gases is superheated above 1,200° C. and directly interacts with the pyrolysis gases that are aspired (in downward dynamic flow through the system of extraction of synthesis gas), to react with the residual carbons of the MPCS (above 1,000° C. and which have not been pyrolyzed at this stage in the pyrolysis chamber 110) and provide the compensatory energy for the oxy-reduction reaction that occurs between these “reducing” carbons and the “oxidizing” molecules of CO.sub.2 and H.sub.2O carried by the pyrolysis gas.

(28) “Endothermic” thermochemical reaction which gasifies said residual carbons of the MPCS and reconverts said CO.sub.2 and H.sub.2O into energy resource of CO and H.sub.2, according to the formulas described by Boudouard:
C+CO.sub.2.fwdarw.2CO and C+H.sub.2O.fwdarw.CO+H.sub.2

(29) The pyrolysis is thus complete without consumption of pyrolysis gas, which would reduce the efficiency of the transfer of the potential energy of the MPCS to the synthesis gas (“syngas”). In contrast, the oxy-reduction reaction that occurs between “reducing” carbons and “oxidizing” molecules of CO.sub.2 provides the “syngas” with molecules of CO (energy resource from reduction of CO.sub.2) that compensates for the endothermia of the final reaction.

(30) The inner face of the double wall 124 of the central chamber 120 is heated to the temperature of the upward gaseous flow (above 1,200° C.). This inner wall of the double wall 124 of the central chamber 120 is in contact with the CO.sub.2, which circulates in said double wall 124 to which it transmits the heat of the central chamber 120. The CO.sub.2 circulating in said double wall 124 is also heated by the outlet tubes (ports) 128 that pass through said double wall 124. The outer wall of the double wall 124 of the central chamber 120 is heated by the CO.sub.2 which circulates in said double wall 124 and transmits the heat carried by said CO.sub.2 circulating in the MPCS contained in the pyrolysis chamber 110. This same CO.sub.2 circulates at a temperature close to 1,200° C. in the upper tubular connections 126 and transmits its thermal capacity to the MPCS that supply the pyrolysis chamber 110. The same CO.sub.2 circulates downward, with a decreasing temperature up to 1,000° C. in the double wall 112 of the pyrolysis chamber 110 with which it exchanges its thermal capacity to the MPCS contained therein. This same CO.sub.2 returns, in a thermosiphon effect circular cycle, in the double wall 124 of the central chamber 120 (through the lower tubular connections 126) where it is reheated by the gaseous flow in said central chamber 120, such gaseous flow circulating with its own circular thermodynamic cycle with thermosiphon effect, generated by partial oxidation of pyrolysis gas generated by said gaseous flow. These two convolutions in the vertical axis thus have the same source of autogenous energy and are interdependent, and their synergistic autothermies contribute to a homogeneous heat exchange with the MPCS in the pyrolysis chamber 110. The conjugated, synergistic and permanent effects of the vertical thermodynamic convolutions create all the symbiotic conditions essential for optimal pyrolysis: complete and close interpenetration of the MPCS by heat transfer gas above 1,200° C., thanks to the overpressure jets of superheated pyrolysis gas coming from the central chamber; instantaneous thermodynamic exchange between the heat transfer gas above 1,200° C. and the MPCS, by convection, conduction, radiation and by a dynamic osmotic effect generated by the conjugation of the interpenetration under pressure (autogenous natural thermodynamic effect) of the heat transfer agent composed of pyrolysis gas (CO+H.sub.2) and molecules of CO.sub.2 and H.sub.2O (originating from oxy-combustion of the fraction of said pyrolysis gases aspired into the cracking chamber 130), wherein these molecules (identical to those that compose the MPCS and from the same already pyrolyzed MPCS) superheated above 1,200° C. are in osmosis with said MPCS; thermodynamic exchange also by the walls of the pyrolysis chamber, due the combined action of static heat exchanges (conduction and radiation of the walls in contact with the MPCS of the double-wall assembly in which the CO.sub.2 between 1,200 and 1,000° C. circulates) and the downward dynamic and thermodynamic flows in the pyrolysis chamber 110.

(31) In addition, the injector 132 may be used as a flame burner to provide the thermal energy necessary to starting the pyrolysis in the device 100. Alternatively a flame burner independent of the injector 132 may be provided.

(32) The device 100 further comprises holes 134 for connecting the assembly of double walls 112, 124 and their tubular connections 126 to an external circulation device ensuring the circulation of CO.sub.2 in these double walls.

(33) The device 100 further comprises a chamber 136 for producing a gas flow of CO.sub.2 in communication with the assembly of double walls 112, 124 and their tubular connections 126. This chamber 136 may comprise a conduit 138 for introducing a portion of the synthesis gas, or any other gas, to generate the gaseous flow of CO.sub.2 autonomously.

(34) FIG. 4 is a schematic view of a non-limiting exemplary embodiment of a facility according to the invention.

(35) The facility 400 shown in FIG. 4 implements an MPCS conversion device, such as for example the device 100 of FIGS. 1-3.

(36) The facility 400 furthermore comprises a supply device 402 that provides MPCS for the conversion device 100. The supply device 402 is connected to the introduction port 106 of the conversion device 100. It comprises, in a non-limiting way, a worm screw 404 (arranged in a sealed conduit) which conveys the MPCS until they are introduced into the pyrolysis chamber 110.

(37) The installation 400 further comprises a device 404 connected to the extraction port 108 for extracting and treating the synthesis gas. The extraction and treatment device 406 comprises, in this order: a first heat exchanger 408 connected to the extraction port 108 to decrease the temperature of the synthesis gas; a cyclone 410 arranged downstream of the first heat exchanger 408 to remove any solid particles in the gas; a second heat exchanger 412 arranged downstream of the cyclone 410 to reduce the synthesis gas temperature to a temperature below 50° C.; and a mechanical extractor 414 comprising a motor 416 to aspirate the synthesis gas.

(38) An example of a non-limiting operation of the conversion device 100 will now be described with reference to FIGS. 1-3. Although described with reference to the device 100, this operation can be applied to any device according to the invention.

(39) The MPCS are introduced into the pyrolysis chamber 110 until said pyrolysis chamber 110 is filled with MPCS and the central chamber 120 is completely immersed in the MPCS. In this configuration, the MPCS occupy the entire pyrolysis chamber from the grill 116 to a level above the CO.sub.2 injection grills 114.

(40) During starting phase, thermal energy is supplied into the central chamber 120, for example, by means of a flame burner or by means of the oxygen injector 132. The supply of thermal energy is carried out until starting the pyrolysis in the pyrolysis chamber 110, that is, until the MPCS reach a temperature greater than or equal to 200° C. As soon the MPCS begin to decompose in pyrolysis gas, the supply of thermal energy is stopped, and the device can operate autonomously.

(41) Under the action of the mechanical extractor 414, the pyrolysis gases are aspired in a downward movement in the pyrolysis chamber 110 through the port 108. A portion of the pyrolysis gases generated in the pyrolysis chamber 110 enters the cracking chamber 130 in the interconnection of the periphery of the base of the cracking chamber 130 with the pyrolysis chamber 110. These pyrolysis gases are at a temperature equal to or above 1,000° C.

(42) The injection of oxygen into the cracking chamber 130 causes oxy-combustion of a fraction of the pyrolysis gases aspired into the cracking chamber 130. This oxy-combustion is eminently exothermic and generates a temperature above 1,200° C., which has several consequences. Firstly, the walls of the cracking chamber 130 as well as the walls 124 and 122 are heated and radiate thermally toward the pyrolysis chamber 110, maintaining the pyrolysis temperature throughout the pyrolysis chamber 110. Secondly, the increase in temperature creates an overpressure in the cracking chamber 130, which forces an upward gas movement into the central chamber 120. This upward movement and the generated overpressure force the gases in the central chamber 120 out of the central chamber 120 through the ports 128 and they penetrate the MPCS present in the pyrolysis chamber. The penetration of very hot gas above 1,200° C. allows: on the one hand, to heat all MPCS present in the pyrolysis chamber; and on the other hand, to bring the compounds CO.sub.2 and H.sub.2O produced by oxy-combustion in contact with the MPCS; these compounds react with the MPCS as oxidants to produce CO and H.sub.2, which allows to perfect the chemical reactions and to increase the efficiency of the pyrolysis of the MPCS.

(43) If necessary, a gaseous flow of CO.sub.2 at 1,200° C. is injected at the top into the pyrolysis chamber via grills 114.

(44) As their pyrolysis progresses, the MPCS moves downward in the pyrolysis chamber. New MPCS are added at the top of the pyrolysis chamber 110.

(45) The temperature of the MPCS gradually increases in the downward direction in the pyrolysis chamber thanks to the thermal energy provided by the central chamber 120, which constitutes the thermal generator of the device 100 according to the invention. At the bottom of the pyrolysis chamber 110, the MPCS and the synthesis gas obtained are at a temperature of less than or equal to 1,200° C.

(46) The synthesis gas obtained is formed mainly, or even exclusively, by CO and H.sub.2.

(47) Of course, the invention is not limited to the examples detailed above.