초록 ▼

A process and gas generator is disclosed for generating by dry distillation of solids and gasification of solids, a fuel gas substantially free of condensable dry distillation volatiles which would interfere with the intended use of the gas, e.g. for powering an internal combustion engine.To achieve

A process and gas generator is disclosed for generating by dry distillation of solids and gasification of solids, a fuel gas substantially free of condensable dry distillation volatiles which would interfere with the intended use of the gas, e.g. for powering an internal combustion engine.To achieve this, solids beds in distinct dry distillation and gasification zones are maintained under conditions favouring thermal cracking of condensable (tar) volatiles in the hot regions of both zones. For optimal control of these conditions these zones are physically separated by internals within a single reactor vessel and optionally by performing part of the dry distillation (pyrolysis) in a separate reactor vessel, in which case pyrolysis volatiles are fed in counter-current to the dry distillation bed, withdrawn from the top thereof and fed into and through the embers bed of the gasification zone. Thermal cracking of pyrolysis volatiles is prolonged and intensified by the manner in which these volatiles are conducted in intimate contact through the embers bed of the gasification zone in co-current therewith. The embers bed is guided along a progressively constricting pathway, which controls the rate of travel of and the period of residence of the solids bed in the process and generator.

대표청구항 ▼

1. A process for the generation of a fuel gas by dry distillation of carbonaceous solids in a dry distillation zone into which the carbonaceous solids are fed via a solids supply and in which the solids are heated, where applicable dried and are dry-distilled with the liberation of dry distillation

1. A process for the generation of a fuel gas by dry distillation of carbonaceous solids in a dry distillation zone into which the carbonaceous solids are fed via a solids supply and in which the solids are heated, where applicable dried and are dry-distilled with the liberation of dry distillation volatiles and, by further conversion of those volatiles in a gasification zone in the presence of carbonaceous solids passing through the gasification zone at least in part under gravity in the form of a bed of particulate solids, to which gasification media are fed in substoichiometric quantities, the dry distillation volatiles withdrawn from the dry distillation zone entering the gasification zone and flowing through the bed of particulate solids being there maintained in co-current with the direction of travel of the latter, an embers bed being formed by the bed of particulate solids in the terminal portion of the gasification zone in the region of a fire grate element acting further as a solids discharge element for the residual solids after completion of the gasification, through which embers bed the gas formed in the bed of particulate solids passes, whereby condensable volatiles components contained in the gas are cracked, and wherein the fuel gas so generated is withdrawn from the lower region of the bed of particulate solids of the gasification zone, wherein gas containing oxygen is introduced into the dry distillation zone in substoichiometric amount for generating heat by partial combustion of the solids to be dry-distilled passing through the dry distillation zone in the form of a bed of particulate solids under the action of gravity before the generated fuel gas product is separated from ashes and any cinders and is withdrawn and forwarded for further use, said process further comprising additional measures for further decreasing the content of condensable dry distillation volatiles in the fuel gas product by increasing the intimate contact of the gases and vapours with the solids beds through which they pass, selected from either or both of the following:A) that the embers bed of the gasification zone is conducted from the higher lying regions of said zone under gravity towards and through a constricted lower peripheral passage region of the gasification zone defined between the outer periphery of the fire grate element and the inner periphery of exterior walls of a reactor in which the process is performed, and in co-current therewith the dry distillation volatiles and gasification gases and any gaseous cracking products are passed in intimate contact with and through the embers bed and from there travels down a funnel-shaped inwardly sloping constricting pathway below the fire grate element leading into and ending with the ash withdrawal region, where the separation occurs between the ashes and any cinders and the generated fuel gas product; B) that in at least one dry distillation zone in the form of a bed of particulate solids under the action of gravity the gas present in that zone passes through the solids in counter-current to the direction of travel of the solids to be dry distilled, the solids thereby being dry distilled and the dry distillation volatiles thereby formed in the dry distillation zone being withdrawn from the dry distillation zone near the solids supply region and that at least part of the dry distillation volatiles formed in the dry distillation zone withdrawn from near the solids supply region feeding the dry distillation zone with carbonaceous solids are from there forwarded into the gasification zone, where they, together with gasification gases and any gaseous cracking products, pass in co-current with and in intimate contact with and through the embers bed of the gasification zone and are subjected to cracking of condensable volatiles, before being separated from ashes and any cinders and being withdrawn as a fuel gas product, subject further to the condition that, at least when feature A) is absent and where the at least one dry distillation zone, wherein the bed of particulate solids and the gas present therein pass in counter-current to one another, is maintained in a first vessel, distinct and separate from a second vessel, wherein the bed of carbonaceous solids and the gases and vapours pass in co-current with one another, (i) the bed of particulate solids in the first vessel is there combusted and gasified substantially entirely to solids residues consisting of ashes, cinders, any non-combustible solids components or uncombusted bulky material residues; and (ii) the solids residues of (i) are withdrawn from the first vessel for disposal; and (iii) the bed of particulate solids in the second vessel is formed from a solids supply separate from the first vessel. 2. Process as claimed in claim 1, including the integers of A), wherein the fuel gas is withdrawn from the ash withdrawal region along a meandering continuation of the aforesaid constricting pathway.3. Process as claimed in claim 1, including the integers of A), wherein the fuel gas is withdrawn in counter-current heat exchange with gasification medium being fed to the gasification zone.4. Process as claimed in claim 1, including the integers of A) and wherein at least part of the dry distillation volatiles formed in the dry distillation zone pass in counter-current to the bed of particulate solids of the dry distillation zone through that bed and are withdrawn from near the solids supply region, feeding the dry distillation zone with carbonaceous solids, and are from there forwarded, at least in part, into the gasification zone; wherein the dry distillation takes place, at least in part, in a first vessel separate from a second vessel, in which the gasification zone is maintained; and wherein from the first vessel, solids residues composed predominantly of non-combustible solids residues are withdrawn from that region of the first distillation vessel which is remote from its solids supply region, whereas the second vessel is supplied with solids for forming its bed of particulate solids, at least in part not being the solids withdrawn from the said region remote from the solids supply region of the first vessel.5. Gas generator suitable for performing the process as claimed in claim 1 for generating a fuel gas product, including solids feeder means discharging into a solids supply portion of a dry distillation zone, in which dry distillation zone solids introduced by the solids feeder means are heated, dried if necessary and subjected to dry distillation, thereby to release dry distillation volatiles into a gasification zone supplied with and containing a bed of gasifiable carbonaceous solids downstream of the dry distillation zone and supported on a fire grate device, restricting the rate of downward movement of the solids of the bed under gravity in co-current with dry distillation volatiles released from the dry distillation zone as well as the gasification media and the generated fuel gas in the gasification zone flowing through the particulate solids bed, a supply of oxygen-bearing gases in the dry distillation zone supporting partial combustion therein for heating the dry distillation zone and a supply of gasification medium being provided for maintaining gasification conditions in the gasification zone by the provision of feed lines for gasification media to be introduced into the particulate solids bed which enter into the gasification zone, at least the lower region of the bed of gasifiable carbonaceous solids being maintained in an embers bed condition through which the dry distillation volatiles and volatilised products of gasification pass in order to be subjected to thermal cracking and including an ash withdrawal region including a gas separation zone and discharge passage for the generated fuel gas product and further including additional features adapted for further decreasing the content of condensable dry distillation volatiles in the fuel gas product by increasing the intimate contact of the gases and vapours with the solids beds through which they pass, selected from either or both of the following:a) that in relation to higher lying regions of the gasification zone (5; 5a; 5b) the fire grate device (73; 73a), acting further as a discharge element for the solids residues of the gasification, defines a constricted peripheral passage (116; 116a) for the embers bed of the gasification zone between the outer periphery of the fire grate device (73; 73a) and the inner periphery of the exterior walls (82, 85) of the gasification zone, which constricted peripheral passage merges into a downwardly and inwardly funnel-like sloping constricting pathway (116; 116a) below the fire grate device leading into and ending with the ash withdrawal region (121; 121a), where the separation occurs between the ashes and any cinders and the generated fuel gas product; b) that through at least one dry distillation zone solids to be dry-distilled pass in the form of a particulate solids bed (30) under the action of gravity, wherein further a gasification medium feed means (3) for an oxygen-containing gas enters below the particulate solids bed (2) and wherein for the withdrawal from the dry distillation zone of the dry distillation volatiles, formed with heat generation by partial combustion of the solids in the dry distillation reactor, a dry distillation gas duct (4) is connected in the region of the solids supply means (1) and so enters into a gasification zone, that the dry distillation gas flows through the particulate solids bed (139) in the gasification zone in intimate contact with and in co-current to the solids material, subject further to the condition that, at least when feature a) is absent and where the at least one dry distillation zone, which is designed for the particulate solids bed therein and the flow of dry distillation volatiles to pass in counter-current to one another, is to be maintained in a first vessel distinct and separate from a second vessel, wherein the bed of carbonaceous solids and gases pass in co-current with one another, (i) the first vessel (2) is designed for the bed of particulate solids to be combusted and gasified substantially entirely to solids residues consisting of ashes, cinders and any noncombustible solids components or uncombusted bulky material residues; and (ii) has a discharge locality (22) at its bottom end for the disposal of the solid residues; and that (iii) the second vessel (5) has its own supply means (6; 68-70) for the introduction, separate from the first vessel (2), of gasifiable material which is to form the bed of particulate solids in the second vessel (5). 6. Gas generator as claimed in claim 5, and including the integers of a), wherein the fuel gas discharge passage(s) passes, at least in part, in heat exchanging counter-current with a feed passage (133) for gasification medium and/or oxygen-bearing gas.7. Gas generator as claimed in claim 5, and including the integers of a), wherein the bottom (114; 114a) of the downwardly and inwardly sloping pathway has a funnel-shaped configuration, forming a sliding surface for the ash, feeding into a central aperture (115; 115a; 115b).8. Gas generator as claimed in claim 5, wherein at least part of the dry distillation zone (2) is accommodated in a first reactor vessel (26) separate from a second reactor vessel (71) accommodating the gasification zone (5), and a duct or passage (4) is provided for feeding dry distillation volatiles from the first vessel into the second vessel.9. Gas generator as claimed in claim 5 and including the integers of b), wherein the solids to be dry-distilled pass through a dry distillation reactor (2) in a particulate solids bed (30) under the action of gravity, wherein further a gasification medium feed means (3) for an oxygen-containing gas enters below the particulate solids bed and wherein for the withdrawal from the dry distillation zone of the dry distillation volatiles, formed with heat generation by partial combustion of the solids in the dry distillation reactor, a dry distillation gas duct (4) is connected in the region of the solids supply means (1) and so enters into a gasification reactor (5) that the dry distillation volatiles flow through the particulate solids bed (139) in the gasification reactor (5) in co-current to the solids material.10. A process for the generation of a fuel gas by dry distillation of carbonaceous solids in a dry distillation zone into which the carbonaceous solids are fed via a solids supply and in which the solids are heated, where applicable dried and are dry-distilled with the liberation of dry distillation volatiles and, by further conversion of those volatiles in a gasification zone in the presence of carbonaceous solids passing through the gasification zone at least in part under gravity in the form of a bed of particulate solids, to which gasification media are fed in substoichiometric quantities, the dry distillation volatiles withdrawn from the dry distillation zone entering the gasification zone and flowing through the bed of particulate solids being there maintained in co-current with the direction of travel of the latter, an embers bed being formed by the bed of particulate solids in the terminal portion of the gasification zone in the region of a fire grate element acting further as a solids discharge element for the residual solids after completion of the gasification, through which embers bed the gas formed in the bed of particulate solids passes, whereby condensable volatiles components contained in the gas are cracked, and wherein the fuel gas so generated is withdrawn from the lower region of the bed of particulate solids of the gasification zone, wherein gas containing oxygen is introduced into the dry distillation zone in substoichiometric amount for generating heat by partial combustion of the solids to be dry-distilled passing through the dry distillation zone in the form of a bed of particulate solids under the action of gravity before the generated fuel gas product is separated from ashes and any cinders and is withdrawn and forwarded for further use, said process further comprising additional measures for further decreasing the content of condensable dry distillation volatiles in the fuel gas product by increasing the intimate contact of the gases and vapours with the solids beds through which they pass, selected from either or both of the following:A) that the embers bed of the gasification zone is conducted from the higher lying regions of said zone under gravity towards and through a constricted lower peripheral passage region of the gasification zone defined between the outer periphery of the fire grate element and the inner periphery of exterior walls of a reactor in which the process is performed, and in co-current therewith the dry distillation volatiles and gasification gases and any gaseous cracking products are passed in intimate contact with and through the embers bed and from there travels down a funnel-shaped inwardly sloping constricting pathway below the fire grate element leading into and ending with the ash withdrawal region, where the separation occurs between the ashes and any cinders and the generated fuel gas product; B) that in at least one dry distillation zone in the form of a bed of particulate solids under the action of gravity the gas present in that zone passes through the solids in counter-current to the direction of travel of the solids to be dry distilled, the solids thereby being dry distilled and the dry distillation volatiles thereby formed in the dry distillation zone being withdrawn from the dry distillation zone near the solids supply region and that at least part of the dry distillation volatiles formed in the dry distillation zone withdrawn from near the solids supply region feeding the dry distillation zone with carbonaceous solids are from there forwarded into the gasification zone, where they, together with gasification gases and any gaseous cracking products, pass in co-current with and in intimate contact with and through the embers bed of the gasification zone and are subjected to cracking of condensable volatiles, before being separated from ashes and any cinders and being withdrawn as a fuel gas product, subject further to the condition that, at least when feature A) is absent and where the at least one dry distillation zone, wherein the bed of particulate solids and the gas present therein pass in counter-current to one another, is maintained in a first vessel, distinct and separate from a second vessel, wherein the bed of carbonaceous solids and the gases and vapours pass in co-current with one another, (i) the bed of particulate solids in the first vessel is there combusted and gasified substantially entirely to solids residues consisting of ashes, cinders, any non-combustible solids components or uncombusted bulky material residues; and (ii) the solids residues of (i) are withdrawn from the first vessel for disposal; and (iii) the bed of particulate solids in the second vessel is formed from a solids supply separate from the first vessel, said process including at least the integers of B) and wherein, at least in the event that the dry distillation zone and the gasification zone are maintained in separate dry distillation and gasification vessels, solids residues composed predominantly of non-combustible solids residues are withdrawn from that region of the dry distillation vessel which is remote from its solids supply region, whereas the gasification vessel is supplied with solids for forming its bed of particulate solids at least in part different from the solids residues withdrawn from the said region remote from the solids supply region of the dry distillation vessel.11. Gas generator for generating a fuel gas product, including solids feeder means discharging into a solids supply portion of a dry distillation zone, in which dry distillation zone solids introduced by the solids feeder means are heated, dried if necessary and subjected to dry distillation, thereby to release dry distillation volatiles into a gasification zone supplied with and containing a bed of gasifiable carbonaceous solids downstream of the dry distillation zone and supported on a fire grate device, restricting the rate of downward movement of the solids of the bed under gravity in co-current with dry distillation volatiles released from the dry distillation zone as well as the gasification media and the generated fuel gas in the gasification zone flowing through the particulate solids bed, a supply of oxygen-bearing gases in the dry distillation zone supporting partial combustion therein for heating the dry distillation zone and a supply of gasification medium being provided for maintaining gasification conditions in the gasification zone by the provision of feed lines for gasification media to be introduced into the particulate solids bed which enter into the gasification zone, at least the lower region of the bed of gasifiable carbonaceous solids being maintained in an embers bed condition through which the dry distillation volatiles and volatilised products of gasification pass in order to be subjected to thermal cracking and including an ash withdrawal region including a gas separation zone and discharge passage for the generated fuel gas product and further including additional features adapted for further decreasing the content of condensable dry distillation volatiles in the fuel gas product by increasing the intimate contact of the gases and vapours with the solids beds through which they pass, selected from either or both of the following:a) that in relation to higher lying regions of the gasification zone (5; 5a; 5b) the fire grate device (73; 73a), acting further as a discharge element for the solids residues of the gasification, defines a constricted peripheral passage (116; 116a) for the embers bed of the gasification zone between the outer periphery of the fire grate device (73; 73a) and the inner periphery of the exterior walls (82, 85) of the gasification zone, which constricted peripheral passage merges into a downwardly and inwardly funnel-like sloping constricting pathway (116; 116a) below the fire grate device leading into and ending with the ash withdrawal region (121; 121a), where the separation occurs between the ashes and any cinders and the generated fuel gas product; b) that through at least one dry distillation zone solids to be dry-distilled pass in the form of a particulate solids bed (30) under the action of gravity, wherein further a gasification medium feed means (3) for an oxygen-containing gas enters below the particulate solids bed (2) and wherein for the withdrawal from the dry distillation zone of the dry distillation volatiles, formed with heat generation by partial combustion of the solids in the dry distillation reactor, a dry distillation gas duct (4) is connected in the region of the solids supply means (1) and so enters into a gasification zone, that the dry distillation gas flows through the particulate solids bed (139) in the gasification zone in intimate contact with and in co-current to the solids material, subject further to the condition that, at least when feature a) is absent and where the at least one dry distillation zone, which is designed for the particulate solids bed therein and the flow of dry distillation volatiles to pass in counter-current to one another, is to be maintained in a first vessel distinct and separate from a second vessel, wherein the bed of carbonaceous solids and gases pass in co-current with one another, (i) the first vessel (2) is designed for the bed of particulate solids to be combusted and gasified substantially entirely to solids residues consisting of ashes, cinders and any noncombustible solids components or uncombusted bulky material residues; and (ii) has a discharge locality (22) at its bottom end for the disposal of the solid residues; and that (iii) the second vessel (5) has its own supply means (6; 68-70) for the introduction, separate from the first vessel (2), of gasifiable material which is to form the bed of particulate solids in the second vessel (5), said gas generator including the integers of a), including baffles (118, 119, 118a, 119a) defining a meandering continuation of the downwardly and inwardly sloping constricting pathway, the meandering continuation forming the inlet side to the discharge passage (123, 128) for generated fuel gas.12. Gas generator for generating a fuel gas product, including solids feeder means discharging into a solids supply portion of a dry distillation zone, in which dry distillation zone solids introduced by the solids feeder means are heated, dried if necessary and subjected to dry distillation, thereby to release dry distillation volatiles into a gasification zone supplied with and containing a bed of gasifiable carbonaceous solids downstream of the dry distillation zone and supported on a fire grate device, restricting the rate of downward movement of the solids of the bed under gravity in co-current with dry distillation volatiles released from the dry distillation zone as well as the gasification media and the generated fuel gas in the gasification zone flowing through the particulate solids bed, a supply of oxygen-bearing gases in the dry distillation zone supporting partial combustion therein for heating the dry distillation zone and a supply of gasification medium being provided for maintaining gasification conditions in the gasification zone by the provision of feed lines for gasification media to be introduced into the particulate solids bed which enter into the gasification zone, at least the lower region of the bed of gasifiable carbonaceous solids being maintained in an embers bed condition through which the dry distillation volatiles and volatilised products of gasification pass in order to be subjected to thermal cracking and including an ash withdrawal region including a gas separation zone and discharge passage for the generated fuel gas product and further including additional features adapted for further decreasing the content of condensable dry distillation volatiles in the fuel gas product by increasing the intimate contact of the gases and vapours with the solids beds through which they pass, selected from either or both of the following:a) that in relation to higher lying regions of the gasification zone (5; 5a; 5b) the fire grate device (73; 73a), acting further as a discharge element for the solids residues of the gasification, defines a constricted peripheral passage (116; 116a) for the embers bed of the gasification zone between the outer periphery of the fire grate device (73; 73a) and the inner periphery of the exterior walls (82, 85) of the gasification zone, which constricted peripheral passage merges into a downwardly and inwardly funnel-like sloping constricting pathway (116; 116a) below the fire grate device leading into and ending with the ash withdrawal region (121; 121a), where the separation occurs between the ashes and any cinders and the generated fuel gas product; b) that through at least one dry distillation zone solids to be dry-distilled pass in the form of a particulate solids bed (30) under the action of gravity, wherein further a gasification medium feed means (3) for an oxygen-containing gas enters below the particulate solids bed (2) and wherein for the withdrawal from the dry distillation zone of the dry distillation volatiles, formed with heat generation by partial combustion of the solids in the dry distillation reactor, a dry distillation gas duct (4) is connected in the region of the solids supply means (1) and so enters into a gasification zone, that the dry distillation gas flows through the particulate solids bed (139) in the gasification zone in intimate contact with and in co-current to the solids material, subject further to the condition that, at least when feature a) is absent and where the at least one dry distillation zone, which is designed for the particulate solids bed therein and the flow of dry distillation volatiles to pass in counter-current to one another, is to be maintained in a first vessel distinct and separate from a second vessel, wherein the bed of carbonaceous solids and gases pass in co-current with one another, (i) the first vessel (2) is designed for the bed of particulate solids to be combusted and gasified substantially entirely to solids residues consisting of ashes, cinders and any non-combustible solids components or uncombusted bulky material residues; and (ii) has a discharge locality (22) at its bottom end for the disposal of the solid residues; and that (iii) the second vessel (5) has its own supply means (6; 68-70) for the introduction, separate from the first vessel (2), of gasifiable material which is to form the bed of particulate solids in the second vessel (5) said gas generator including the integers of a), wherein the fire grate device (73; 73a) is a rotary fire grate device; wherein the rotary fire grate device (73; 73a) has a downwardly conically or pyramidally flaring bed support surface; and wherein the rotary fire grate device (73; 73a) is mounted on a central rotary drive shaft (74; 74a) which includes a feed passage for oxygen-bearing gas and/or gasifying medium.13. Gas generator as claimed in claim 12, wherein the rotary fire grate device includes a vertical succession of conically or pyramidally flaring bed support surfaces (109, 110; 109a , 110a).14. Gas generator for generating a fuel gas product, including solids feeder means discharging into a solids supply portion of a dry distillation zone, in which dry distillation zone solids introduced by the solids feeder means are heated, dried if necessary and subjected to dry distillation, thereby to release dry distillation volatiles into a gasification zone supplied with and containing a bed of gasifiable carbonaceous solids downstream of the dry distillation zone and supported on a fire grate device, restricting the rate of downward movement of the solids of the bed under gravity in co-current with dry distillation volatiles released from the dry distillation zone as well as the gasification media and the generated fuel gas in the gasification zone flowing through the particulate solids bed, a supply of oxygen-bearing gases in the dry distillation zone supporting partial combustion therein for heating the dry distillation zone and a supply of gasification medium being provided for maintaining gasification conditions in the gasification zone by the provision of feed lines for gasification media to be introduced into the particulate solids bed which enter into the gasification zone, at least the lower region of the bed of gasifiable carbonaceous solids being maintained in an embers bed condition through which the dry distillation volatiles and volatilised products of gasification pass in order to be subjected to thermal cracking and including an ash withdrawal region including a gas separation zone and discharge passage for the generated fuel gas product and further including additional features adapted for further decreasing the content of condensable dry distillation volatiles in the fuel gas product by increasing the intimate contact of the gases and vapours with the solids beds through which they pass, selected from either or both of the following:a) that in relation to higher lying regions of the gasification zone (5; 5a; 5b) the fire grate device (73; 73a), acting further as a discharge element for the solids residues of the gasification, defines a constricted peripheral passage (116; 116a) for the embers bed of the gasification zone between the outer periphery of the fire grate device (73; 73a) and the inner periphery of the exterior walls (82, 85) of the gasification zone, which constricted peripheral passage merges into a downwardly and inwardly funnel-like sloping constricting pathway (116; 116a) below the fire grate device leading into and ending with the ash withdrawal region (121; 121a), where the separation occurs between the ashes and any cinders and the generated fuel gas product; b) that through at least one dry distillation zone solids to be dry-distilled pass in the form of a particulate solids bed (30) under the action of gravity, wherein further a gasification medium feed means (3) for an oxygen-containing gas enters below the particulate solids bed (2) and wherein for the withdrawal from the dry distillation zone of the dry distillation volatiles, formed with heat generation by partial combustion of the solids in the dry distillation reactor, a dry distillation gas duct (4) is connected in the region of the solids supply means (1) and so enters into a gasification zone, that the dry distillation gas flows through the particulate solids bed (139) in the gasification zone in intimate contact with and in co-current to the solids material, subject further to the condition that, at least when feature a) is absent and where the at least one dry distillation zone, which is designed for the particulate solids bed therein and the flow of dry distillation volatiles to pass in counter-current to one another, is to be maintained in a first vessel distinct and separate from a second vessel, wherein the bed of carbonaceous solids and gases pass in co-current with one another, (i) the first vessel (2) is designed for the bed of particulate solids to be combusted and gasified substantially entirely to solids residues consisting of ashes, cinders and any noncombustible solids components or uncombusted bulky material residues; and (ii) has a discharge locality (22) at its bottom end for the disposal of the solid residues; and that (iii) the second vessel (5) has its own supply means (6; 68-70) for the introduction, separate from the first vessel (2), of gasifiable material which is to form the bed of particulate solids in the second vessel (5), said gas generator including the integers of a), wherein the underside of the fire grate device (73; 73a) defining the upper side of the downwardly and inwardly sloping constricted pathway includes formations (122) acting on the movement of the bed in the constricted pathway.15. Gas generator for generating a fuel gas product, including solids feeder means discharging into a solids supply portion of a dry distillation zone, in which dry distillation zone solids introduced by the solids feeder means are heated, dried if necessary and subjected to dry distillation, thereby to release dry distillation volatiles into a gasification zone supplied with and containing a bed of gasifiable carbonaceous solids downstream of the dry distillation zone and supported on a fire grate device, restricting the rate of downward movement of the solids of the bed under gravity in co-current with dry distillation volatiles released from the dry distillation zone as well as the gasification media and the generated fuel gas in the gasification zone flowing through the particulate solids bed, a supply of oxygen-bearing gases in the dry distillation zone supporting partial combustion therein for heating the dry distillation zone and a supply of gasification medium being provided for maintaining gasification conditions in the gasification zone by the provision of feed lines for gasification media to be introduced into the particulate solids bed which enter into the gasification zone, at least the lower region of the bed of gasifiable carbonaceous solids being maintained in an embers bed condition through which the dry distillation volatiles and volatilised products of gasification pass in order to be subjected to thermal cracking and including an ash withdrawal region including a gas separation zone and discharge passage for the generated fuel gas product and further including additional features adapted for further decreasing the content of condensable dry distillation volatiles in the fuel gas product by increasing the intimate contact of the gases and vapours with the solids beds through which they pass, selected from either or both of the following:a) that in relation to higher lying regions of the gasification zone (5; 5a; 5b) the fire grate device (73; 73a), acting further as a discharge element for the solids residues of the gasification, defines a constricted peripheral passage (116; 116a) for the embers bed of the gasification zone between the outer periphery of the fire grate device (73; 73a) and the inner periphery of the exterior walls (82, 85) of the gasification zone, which constricted peripheral passage merges into a downwardly and inwardly funnel-like sloping constricting pathway (116; 116a) below the fire grate device leading into and ending with the ash withdrawal region (121; 121a), where the separation occurs between the ashes and any cinders and the generated fuel gas product; b) that through at least one dry distillation zone solids to be dry-distilled pass in the form of a particulate solids bed (30) under the action of gravity, wherein further a gasification medium feed means (3) for an oxygen-containing gas enters below the particulate solids bed (2) and wherein for the withdrawal from the dry distillation zone of the dry distillation volatiles, formed with heat generation by partial combustion of the solids in the dry distillation reactor, a dry distillation gas duct (4) is connected in the region of the solids supply means (1) and so enters into a gasification zone, that the dry distillation gas flows through the particulate solids bed (139) in the gasification zone in intimate contact with and in co-current to the solids material, subject further to the condition that, at least when feature a) is absent and where the at least one dry distillation zone, which is designed for the particulate solids bed therein and the flow of dry distillation volatiles to pass in counter-current to one another, is to be maintained in a first vessel distinct and separate from a second vessel, wherein the bed of carbonaceous solids and gases pass in co-current with one another, (i) the first vessel (2) is designed for the bed of particulate solids to be combusted and gasified substantially entirely to solids residues consisting of ashes, cinders and any non-combustible solids components or uncombusted bulky material residues; and (ii) has a discharge locality (22) at its bottom end for the disposal of the solid residues; and that (iii) the second vessel (5) has its own supply means (6; 68-70) for the introduction, separate from the first vessel (2), of gasifiable material which is to form the bed of particulate solids in the second vessel (5), said gas generator including the integers of a), wherein the fire grate device (73; 73a) and solids discharge element includes a hollow conical or pyramidal body (109; 109a) connected to a supply (104, 99) of gasifying medium and having gasifying medium outlet formations (103) on its underside (113) leading into a region of the gasification zone where gasification conditions are to be maintained.16. Gas generator as claimed in claim 15, wherein the rotary fire grate device includes a vertical succession of conically or pyramidally flaring bed support surfaces (109, 110; 109a , 110a) and wherein the underside of the hollow conical or pyramidal body (110; 110a) communicates with the apex region of a further hollow conical or pyramidal body (109; 109a), through which the gasification medium is to be supplied.17. Gas generator for generating a fuel gas product, including solids feeder means discharging into a solids supply portion of a dry distillation zone, in which dry distillation zone solids introduced by the solids feeder means are heated, dried if necessary and subjected to dry distillation, thereby to release dry distillation volatiles into a gasification zone supplied with and containing a bed of gasifiable carbonaceous solids downstream of the dry distillation zone and supported on a fire grate device, restricting the rate of downward movement of the solids of the bed under gravity in co-current with dry distillation volatiles released from the dry distillation zone as well as the gasification media and the generated fuel gas in the gasification zone flowing through the particulate solids bed, a supply of oxygen-bearing gases in the dry distillation zone supporting partial combustion therein for heating the dry distillation zone and a supply of gasification medium being provided for maintaining gasification conditions in the gasification zone by the provision of feed lines for gasification media to be introduced into the particulate solids bed which enter into the gasification zone, at least the lower region of the bed of gasifiable carbonaceous solids being maintained in an embers bed condition through which the dry distillation volatiles and volatilised products of gasification pass in order to be subjected to thermal cracking and including an ash withdrawal region including a gas separation zone and discharge passage for the generated fuel gas product and further including additional features adapted for further decreasing the content of condensable dry distillation volatiles in the fuel gas product by increasing the intimate contact of the gases and vapours with the solids beds through which they pass, selected from either or both of the following:a) that in relation to higher lying regions of the gasification zone (5; 5a; 5b) the fire grate device (73; 73a), acting further as a discharge element for the solids residues of the gasification, defines a constricted peripheral passage (116; 116a) for the embers bed of the gasification zone between the outer periphery of the fire grate device (73; 73a) and the inner periphery of the exterior walls (82, 85) of the gasification zone, which constricted peripheral passage merges into a downwardly and inwardly funnel-like sloping constricting pathway (116; 116a) below the fire grate device leading into and ending with the ash withdrawal region (121; 121a), where the separation occurs between the ashes and any cinders and the generated fuel gas product; b) that through at least one dry distillation zone solids to be dry-distilled pass in the form of a particulate solids bed (30) under the action of gravity, wherein further a gasification medium feed means (3) for an oxygen-containing gas enters below the particulate solids bed (2) and wherein for the withdrawal from the dry distillation zone of the dry distillation volatiles, formed with heat generation by partial combustion of the solids in the dry distillation reactor, a dry distillation gas duct (4) is connected in the region of the solids supply means (1) and so enters into a gasification zone, that the dry distillation gas flows through the particulate solids bed (139) in the gasification zone in intimate contact with and in co-current to the solids material, subject further to the condition that, at least when feature a) is absent and where the at least one dry distillation zone, which is designed for the particulate solids bed therein and the flow of dry distillation volatiles to pass in counter-current to one another, is to be maintained in a first vessel distinct and separate from a second vessel, wherein the bed of carbonaceous solids and gases pass in co-current with one another, (i) the first vessel (2) is designed for the bed of particulate solids to be combusted and gasified substantially entirely to solids residues consisting of ashes, cinders and any non-combustible solids components or uncombusted bulky material residues; and (ii) has a discharge locality (22) at its bottom end for the disposal of the solid residues; and that (iii) the second vessel (5) has its own supply means (6; 68-70) for the introduction, separate from the first vessel (2), of gasifiable material which is to form the bed of particulate solids in the second vessel (5), and wherein in the discharge region of the gasification zone for the discharge of the solids residues a baffle device (118, 119; 118a, 119a) is provided in such a manner that the discharge of solids residues is limited to a maximum solids particle size and/or to a limited discharge rate and wherein for the separation of solids residues to be discharged and fuel gas to be released, a gas passage formation (124; 130) is provided, guiding the fuel gas out of the solids residues bed along a meandering pathway (130, 130a, 130b). 18. Gas generator for generating a fuel gas product, including solids feeder means discharging into a solids supply portion of a dry distillation zone, in which dry distillation zone solids introduced by the solids feeder means are heated, dried if necessary and subjected to dry distillation, thereby to release dry distillation volatiles into a gasification zone supplied with and containing a bed of gasifiable carbonaceous solids downstream of the dry distillation zone and supported on a fire grate device, restricting the rate of downward movement of the solids of the bed under gravity in co-current with dry distillation volatiles released from the dry distillation zone as well as the gasification media and the generated fuel gas in the gasification zone flowing through the particulate solids bed, a supply of oxygen-bearing gases in the dry distillation zone supporting partial combustion therein for heating the dry distillation zone and a supply of gasification medium being provided for maintaining gasification conditions in the gasification zone by the provision of feed lines for gasification media to be introduced into the particulate solids bed which enter into the gasification zone, at least the lower region of the bed of gasifiable carbonaceous solids being maintained in an embers bed condition through which the dry distillation volatiles and volatilised products of gasification pass in order to be subjected to thermal cracking and including an ash withdrawal region including a gas separation zone and discharge passage for the generated fuel gas product and further including additional features adapted for further decreasing the content of condensable dry distillation volatiles in the fuel gas product by increasing the intimate contact of the gases and vapours with the solids beds through which they pass, selected from either or both of the following:a) that in relation to higher lying regions of the gasification zone (5; 5a; 5b) the fire grate device (73; 73a), acting further as a discharge element for the solids residues of the gasification, defines a constricted peripheral passage (116; 116a) for the embers bed of the gasification zone between the outer periphery of the fire grate device (73; 73a) and the inner periphery of the exterior walls (82, 85) of the gasification zone, which constricted peripheral passage merges into a downwardly and inwardly funnel-like sloping constricting pathway (116; 116a) below the fire grate device leading into and ending with the ash withdrawal region (121; 121a), where the separation occurs between the ashes and any cinders and the generated fuel gas product; b) that through at least one dry distillation zone solids to be dry-distilled pass in the form of a particulate solids bed (30) under the action of gravity, wherein further a gasification medium feed means (3) for an oxygen-containing gas enters below the particulate solids bed (2) and wherein for the withdrawal from the dry distillation zone of the dry distillation volatiles, formed with heat generation by partial combustion of the solids in the dry distillation reactor, a dry distillation gas duct (4) is connected in the region of the solids supply means (1) and so enters into a gasification zone, that the dry distillation gas flows through the particulate solids bed (139) in the gasification zone in intimate contact with and in co-current to the solids material, subject further to the condition that, at least when feature a) is absent and where the at least one dry distillation zone, which is designed for the particulate solids bed therein and the flow of dry distillation volatiles to pass in counter-current to one another, is to be maintained in a first vessel distinct and separate from a second vessel, wherein the bed of carbonaceous solids and gases pass in co-current with one another, (i) the first vessel (2) is designed for the bed of particulate solids to be combusted and gasified substantially entirely to solids residues consisting of ashes, cinders and any non-combustible solids components or uncombusted bulky material residues; and (ii) has a discharge locality (22) at its bottom end for the disposal of the solid residues; and that (iii) the second vessel (5) has its own supply means (6; 68-70) for the introduction, separate from the first vessel (2), of gasifiable material which is to form the bed of particulate solids in the second vessel (5), said gas generator including the integers of a), wherein the discharge element (73; 73a) is fitted to a drive shaft (74; 74a) which is rotatable in the particulate solids bed, and wherein the drive shaft (74; 74a) of the discharge element in the gasification reactor is designed as a hollow shaft and serves as a gas duct.19. Gas generator for generating a fuel gas product, including solids feeder means discharging into a solids supply portion of a dry distillation zone, in which dry distillation zone solids introduced by the solids feeder means are heated, dried if necessary and subjected to dry distillation, thereby to release dry distillation volatiles into a gasification zone supplied with and containing a bed of gasifiable carbonaceous solids downstream of the dry distillation zone and supported on a fire grate device, restricting the rate of downward movement of the solids of the bed under gravity in co-current with dry distillation volatiles released from the dry distillation zone as well as the gasification media and the generated fuel gas in the gasification zone flowing through the particulate solids bed, a supply of oxygen-bearing gases in the dry distillation zone supporting partial combustion therein for heating the dry distillation zone and a supply of gasification medium being provided for maintaining gasification conditions in the gasification zone by the provision of feed lines for gasification media to be introduced into the particulate solids bed which enter into the gasification zone, at least the lower region of the bed of gasifiable carbonaceous solids being maintained in an embers bed condition through which the dry distillation volatiles and volatilised products of gasification pass in order to be subjected to thermal cracking and including an ash withdrawal region including a gas separation zone and discharge passage for the generated fuel gas product and further including additional features adapted for further decreasing the content of condensable dry distillation volatiles in the fuel gas product by increasing the intimate contact of the gases and vapours with the solids beds through which they pass, selected from either or both of the following:a) that in relation to higher lying regions of the gasification zone (5; 5a; 5b) the fire grate device (73; 73a), acting further as a discharge element for the solids residues of the gasification, defines a constricted peripheral passage (116; 116a) for the embers bed of the gasification zone between the outer periphery of the fire grate device (73; 73a) and the inner periphery of the exterior walls (82, 85) of the gasification zone, which constricted peripheral passage merges into a downwardly and inwardly funnel-like sloping constricting pathway (116; 116a) below the fire grate device leading into and ending with the ash withdrawal region (121; 121a), where the separation occurs between the ashes and any cinders and the generated fuel gas product; b) that through at least one dry distillation zone solids to be dry-distilled pass in the form of a particulate solids bed (30) under the action of gravity, wherein further a gasification medium feed means (3) for an oxygen-containing gas enters below the particulate solids bed (2) and wherein for the withdrawal from the dry distillation zone of the dry distillation volatiles, formed with heat generation by partial combustion of the solids in the dry distillation reactor, a dry distillation gas duct (4) is connected in the region of the solids supply means (1) and so enters into a gasification zone, that the dry distillation gas flows through the particulate solids bed (139) in the gasification zone in intimate contact with and in co-current to the solids material, subject further to the condition that, at least when feature a) is absent and where the at least one dry distillation zone, which is designed for the particulate solids bed therein and the flow of dry distillation volatiles to pass in counter-current to one another, is to be maintained in a first vessel distinct and separate from a second vessel, wherein the bed of carbonaceous solids and gases pass in co-current with one another, (i) the first vessel (2) is designed for the bed of particulate solids to be combusted and gasified substantially entirely to solids residues consisting of ashes, cinders and any non-combustible solids components or uncombusted bulky material residues; and (ii) has a discharge locality (22) at its bottom end for the disposal of the solid residues; and that (iii) the second vessel (5) has its own supply means (6; 68-70) for the introduction, separate from the first vessel (2), of gasifiable material which is to form the bed of particulate solids in the second vessel (5), wherein at least part of the dry distillation zone (2) is accommodated in a first reactor vessel (26) separate from a second reactor vessel (71) accommodating the gasification zone (5), and a duct or passage (4) is provided for feeding dry distillation volatiles from the first vessel into the second vessel and wherein the first reactor vessel (26) includes a solids feeder (27, 28, 29) means discharging into a solids supply portion of a dry distillation zone, in which dry distillation zone solids introduced by the solids feeder means are heated, dried if necessary and subjected to dry distillation, thereby to release dry distillation volatiles and a fire grate device, between which and the solids feeder a dry distillation zone (2) is situated, and feed means (3) for oxygen-containing gas enter into a lower region of the dry distillation zone (2) from where partial combustion conditions are to be created, as well as gas withdrawal ducts connected to the upper region of the dry distillation zone (2); and wherein the duct or passage (4) for feeding dry distillation volatiles from the first reactor vessel (26) into the second reactor vessel (71) enter the second vessel in an upper region (96) of the second reactor vessel.20. Gas generator for generating a fuel gas product, including solids feeder means discharging into a solids supply portion of a dry distillation zone, in which dry distillation zone solids introduced by the solids feeder means are heated, dried if necessary and subjected to dry distillation, thereby to release dry distillation volatiles into a gasification zone supplied with and containing a bed of gasifiable carbonaceous solids downstream of the dry distillation zone and supported on a fire grate device, restricting the rate of downward movement of the solids of the bed under gravity in co-current with dry distillation volatiles released from the dry distillation zone as well as the gasification media and the generated fuel gas in the gasification zone flowing through the particulate solids bed, a supply of oxygen-bearing gases in the dry distillation zone supporting partial combustion therein for heating the dry distillation zone and a supply of gasification medium being provided for maintaining gasification conditions in the gasification zone by the provision of feed lines for gasification media to be introduced into the particulate solids bed which enter into the gasification zone, at least the lower region of the bed of gasifiable carbonaceous solids being maintained in an embers bed condition through which the dry distillation volatiles and volatilised products of gasification pass in order to be subjected to thermal cracking and including an ash withdrawal region including a gas separation zone and discharge passage for the generated fuel gas product and further including additional features adapted for further decreasing the content of condensable dry distillation volatiles in the fuel gas product by increasing the intimate contact of the gases and vapours with the solids beds through which they pass, selected from either or both of the following:a) that in relation to higher lying regions of the gasification zone (5; 5a; 5b) the fire grate device (73; 73a), acting further as a discharge element for the solids residues of the gasification, defines a constricted peripheral passage (116; 116a) for the embers bed of the gasification zone between the outer periphery of the fire grate device (73; 73a) and the inner periphery of the exterior walls (82, 85) of the gasification zone, which constricted peripheral passage merges into a downwardly and inwardly funnel-like sloping constricting pathway (116; 116a) below the fire grate device leading into and ending with the ash withdrawal region (121; 121a), where the separation occurs between the ashes and any cinders and the generated fuel gas product; b) that through at least one dry distillation zone solids to be dry-distilled pass in the form of a particulate solids bed (30) under the action of gravity, wherein further a gasification medium feed means (3) for an oxygen-containing gas enters below the particulate solids bed (2) and wherein for the withdrawal from the dry distillation zone of the dry distillation volatiles, formed with heat generation by partial combustion of the solids in the dry distillation reactor, a dry distillation gas duct (4) is connected in the region of the solids supply means (1) and so enters into a gasification zone, that the dry distillation gas flows through the particulate solids bed (139) in the gasification zone in intimate contact with and in co-current to the solids material, subject further to the condition that, at least when feature a) is absent and where the at least one dry distillation zone, which is designed for the particulate solids bed therein and the flow of dry distillation volatiles to pass in counter-current to one another, is to be maintained in a first vessel distinct and separate from a second vessel, wherein the bed of carbonaceous solids and gases pass in co-current with one another, (i) the first vessel (2) is designed for the bed of particulate solids to be combusted and gasified substantially entirely to solids residues consisting of ashes, cinders and any non-combustible solids components or uncombusted bulky material residues; and (ii) has a discharge locality (22) at its bottom end for the disposal of the solid residues; and that (iii) the second vessel (5) has its own supply means (6; 68-70) for the introduction, separate from the first vessel (2), of gasifiable material which is to form the bed of particulate solids in the second vessel (5), said gas generator including a cylindrical shaft reactor and a coaxial drive shaft (74; 74a; 74b) carrying a rotary fire grate and/or bed support and/or bed agitation/reconstitution means and discharge element (73; 73a; 73b), including an inlet (276) for oxygen-containing gas near the top (273) of the solids supply region (271, 272) of the cylindrical shaft reactor (5b) and including a supply pipe (274) for oxygen-containing gas surrounding the drive shaft (74; 74a; 74b) forming a gas passage leading from near the said top (273) down into an upper partial combustion region of the solids bed.21. Gas generator as claimed in claim 20, wherein the lower end of the supply pipe (274) is associated with a further rotary bed agitating member (278).