WO2023135114A1

WO2023135114A1 - Process to prepare synthesis gas

Info

Publication number: WO2023135114A1
Application number: PCT/EP2023/050396
Authority: WO
Inventors: Robert Hugo BERENDS
Original assignee: Torrgas Technology B.V
Priority date: 2022-01-11
Filing date: 2023-01-10
Publication date: 2023-07-20

Abstract

The invention is directed to a process to prepare synthesis gas from a solid torrefied biomass feed comprising the following steps: (a)subjecting the solid torrefied biomass to a mild gasification in a reactor to obtain a gaseous fraction comprising hydrogen, carbon monoxide and a mixture of gaseous organic compounds and a solid char, (b) separating the gaseous fraction from the solid char, (c) transferring the gaseous fraction via a transfer conduit and wherein oxygen is added to the gaseous fraction as it is transferred such that the temperature of the gaseous fraction in the transfer conduit is maintained above condensation temperature of hydrocarbons preferably above 450 ºC, and (d) subjecting the gaseous fraction to a partial oxidation in the partial oxidation reactor to obtain the synthesis gas.

Description

PROCESS TO PREPARE SYNTHESIS GAS

The invention is directed to a process to prepare synthesis gas comprising carbon monoxide and hydrogen from a solid torrefied biomass.

Such a process is described in W02020/055254. The illustrated process is performed by first contacting a pellet of a torrefied biomass feed with a mixture of oxygen and super heated steam at mild gasification conditions of 622 C and 0.1 MPa and at a solids residence time of between 15 and 20 minutes. In this mild gasification process a gaseous fraction comprising hydrogen, carbon monoxide and a mixture of gaseous organic compounds and a solid char is obtained. The char is separated and may find application as a product in various applications. The gaseous fraction, not comprising the solid char, is subsequently subjected to a partial oxidation at a temperature exceeding 1000 °C to obtain the synthesis gas. The advantage of this process is that a chemical grade synthesis gas may be obtained while avoiding the formation of a slag. This is achieved by performing the partial oxidation in the absence of slag forming ash compounds which remain in the char product.

A problem of the above process described in W02020/055254 is that between the mild gasification and the high temperature partial oxidation the organic compounds as present in the gaseous fraction may condense and foul the process equipment. The object of the present invention is to provide a process which does not have this problem.

This is achieved by the following process. Process to prepare synthesis gas comprising carbon monoxide and hydrogen from a solid torrefied biomass feed by a process comprising the following steps

(a) subjecting the solid torrefied biomass to a mild gasification in a mild gasification reactor to obtain a gaseous fraction comprising hydrogen, carbon monoxide and a mixture of gaseous organic compounds and a solid char,

(b) separating the gaseous fraction from the solid char, (c) transferring the gaseous fraction via a transfer conduit having an upstream part at the mild gasification reactor and a downstream end fluidly connected to a partial oxidation reactor and wherein oxygen is added to the gaseous fraction as it is transferred via the transfer conduit to combust part of the combustible components such that the temperature of the gaseous fraction in the transfer conduit is maintained above the condensation temperature of the gaseous organic compounds in the gaseous fraction, and

(d) subjecting the gaseous fraction to a partial oxidation in the partial oxidation reactor to obtain the synthesis gas.

Applicants found that by combustion of part of the compounds by purposely adding oxygen in the transfer line the temperature can be maintained high enough to avoid that the tar like hydrocarbons condense and foul the transfer conduit. Such a process is more advantageous than only insulation of the transfer conduit because it can be controlled depending on operational and external conditions. An insulated conduit may still cause issues when for example the temperature of the gaseous fraction is temporarily lower than normal, when cold spots would exist or when the external ambient temperature is much lower than the lower design temperature.

The process shall be described in more detail below.

The solid torrefied biomass feed has been obtained by torrefaction of a starting material comprising lignocellulosic material. Such a process not only increases the heating value per mass biomass by torrefaction but will also remove a substantial amount of water, especially so-called bound-water, from the starting material comprising lignocellulosic material, further also referred to as biomass material. The energy density of the biomass material is increased by decomposing all or part of the hemicelluloses as present in the biomass. An advantage of using a torrefied biomass feed is that the properties of torrefied biomass feeds obtained from different biomass sources may be more uniform than the properties of the original biomass sources. This simplifies the operation of the process according to the invention. Torrefaction is a well-known process and for example described in W02012/102617 and in the earlier referred to publication of Prins et al. in Energy and is sometimes referred to as roasting. In such a process the biomass is heated to an elevated temperature, suitably between 260 and 310 °C and more preferably between 250 and 290 °C, in the absence of oxygen. Torrefaction conditions are so chosen that hemicelluloses decomposes while keeping the celluloses and lignin mostly intact. These conditions may vary for the type of biomass material used as feed. The temperature and residence time of the torrefaction process is further preferably so chosen that the resulting material has a high content of so-called volatiles, i.e. organic compounds. The solids residence time is suitably at least 5 and preferably at least 10 minutes. The upper residence time will determine the amount of volatiles which remain in the torrefied biomass. Preferably the content of volatiles is between 50 and 80 wt%, more preferably between 60 and 80 wt% and even more preferably between 65 and 75 wt%. The volatile content is measured using DIN 51720-2001-03. Applicants found that the relatively high volatile content in the torrefied biomass is advantageous to achieve a high syngas yield.

In the torrefaction process the atomic hydrogen over carbon (H/C) ratio and the atomic oxygen over carbon (O/C) ratio of the biomass material is reduced. Preferably the solid torrefied biomass feed have an atomic hydrogen over carbon (H/C) ratio of between 1 and 1 .4 and an atomic oxygen over carbon (O/C) ratio of between 0.4 and 0.6. Further the water content will reduce in a torrefaction process. The solid torrefied biomass suitably contains less than 7 wt%, and more preferably less than 4 wt% water, based on the total weight of the solid torrefied biomass.

The biomass material to be torrefied may be any material comprising hemicellulose including virgin biomass and waste biomass. Virgin biomass includes all naturally occurring terrestrial plants such as trees, i.e. wood, bushes and grass. Waste biomass is produced as a low value by-product of various industrial sectors such as the agricultural and forestry sector. Examples of agriculture waste biomass are com stover, sugarcane bagasse, beet pulp, rice straw, rice hulls, barley straw, corn cobs, wheat straw, canola straw, rice straw, oat straw, oat hulls and corn fibre. A specific example is palm oil waste such as oil palm fronds (OPF), roots and trunks and the by-products obtained at the palm oil mill, such as for example empty fruit bunches (EFB), fruit fibres, kernel shells, palm oil mill effluent and palm kernel cake. Examples of forestry waste biomass are pre-commercial trees and brush, tree tops, limbs and logging residues and saw mill and paper mill discards. For urban areas, the best potential plant biomass feedstock includes yard waste, for example grass clippings, leaves, tree clippings, and brush, and vegetable processing waste. Waste biomass may also be Specified Recovered Fuel (SRF) comprising lignocellulose.

The biomass material to be torrefied may be a mixture originating from different lignocellulosic feedstocks. Furthermore, the biomass feed may comprise fresh lignocellulosic compounds, partially dried lignocellulosic compounds, fully dried lignocellulosic compounds or a combination thereof.

In the torrefaction process chips of torrefied biomass may be obtained when woody biomass is processed having dimensions in the cm range. Such chips may be directly used in the present process. When the torrefied biomass is required to be transported, for example via roads, waterways or even oceans, it is preferred that the torrefied product is milled to a powder and that the powder is compressed into particles, such as pellets or briquettes. Such compressed particles may have any shape, such as cylinders, pillow shape like in briquettes, cubes. Preferably the smallest distance from the surface of such a pellet to its centre is less than 10 mm. This is advantageous for mass transport within the pellet while performing the pyrolysis or mild gasification process. For example a suitable pellet may have the shape of a cylinder suitably having a diameter of between 5 and 12 mm and preferably between 5 and 10 mm. The length of such cylinders may be between 5 and 50 mm, preferably between 40 and 80 mm and more preferably between 40 and 70 mm. These pellets can be directly used as feed to the present process. In order to increase the strength of such a particle starch may be added or more preferably some waste plastic as described in W02021/084016. Adding waste plastic is advantageous because it results in more stronger pellets and in a higher yield of syngas next to that chemical recycling of waste plastics is made possible.

Step (a) is preferably performed at so-called non-slagging conditions as described in the earlier referred to W02020/055254. This avoids the formation of slag and thus no special measures have to be taken for discharge of the slag and/or protection of the process equipment against the slag or molten slag. The latter enables one to use simpler process equipment. These non-slagging conditions are achieved by performing the process at a temperature of between 500 and 800 °C and at a solid residence time of between 10 and 80 minutes. Good results may already be achieved at a residence time of about 15 minutes. The residence time will be chosen within the claimed range such that the reduction in atomic hydrogen over carbon (H/C) ratio of the solids in step (a) is greater than 50%, preferably greater than 70% and the reduction in atomic oxygen over carbon (O/C) ratio of the solids is greater than 80%. The char particles as obtained preferably have an atomic hydrogen over carbon (H/C) ratio of between 0.02 and 0.1 and an atomic oxygen over carbon (O/C) ratio of between 0.01 and 0.06.

The mild gasification conditions at which step (a) is performed is advantageous compared to pyrolysis because less measures have to be taken to generate the required reaction temperature. Other advantages are increased devolatilization and improved char quality, in terms of less volatiles, due to a better heat distribution over the reactor and therefore an improved heat transfer. The char product as obtained preferably has a content of volatiles of less than 6 wt.%.

The absolute pressure at which steps (a) to (d) is performed may vary between 90 kPa and 10 MPa and preferably between 90 kPa and 5 MPa. Pressures at the higher end of these ranges are advantageous when the syngas is to be used in downstream processes which require a syngas having such elevated or even higher pressures. The lower pressure range may be used when the gaseous reaction products and/or the syngas as prepared from this reaction product is used as fuel for a gas engine or steam boiler to generate electricity.

When step (a) is performed at an elevated pressure the solids and an optional carrier gas will have to be brought to that pressure level before being able to feed this mixture to a reactor in which the process is performed. Pressurisation may be performed using a solids pump as for example described in US4988239, US2009178336 and WO11044911. The pressurisation of the solid biomass may also be performed in a lock hopper as described in US4955989 and US2011100274. When compressed particles are used such a lock hopper is preferred. The mild gasification of step (a) is suitably performed in the presence of oxygen and wherein the amount of oxygen as supplied to the mild gasification reactor is between 0.1 and 0.3 mass oxygen per mass biomass as supplied to step (a). More preferably also H2O as super heated steam is added to step (a) and wherein the content of oxygen is between 20 and 40 vol.% O2 per combined O2 and H2O.

The oxygen may be supplied as air or enriched air. Suitably oxygen is supplied as part of an oxygen comprising gas having an oxygen content of at least 90 vol%, more preferably at least 94 vol%, wherein nitrogen, carbon dioxide and argon may be present as impurities. Such substantially pure oxygen is preferred because a syngas containing lower amounts of nitrogen may be obtained. Such substantially pure oxygen may be prepared by an air separation unit (ASU) or by a water splitter, also referred to as electrolysis.

In step (a) a gaseous fraction comprising hydrogen, carbon monoxide and a mixture of gaseous organic compounds and a solid fraction comprising of char particles is obtained. The gaseous organic compounds may comprise of noncondensed organic compounds. These compounds range from methane to organic compounds having up to 50 carbon atoms and even more. The organic compounds include hydrocarbons and oxygenated hydrocarbons. The content of these organic compounds in the gaseous fraction may be greater than 15 wt% and even be between 40 to 70 wt%. The gaseous fraction may also contain sulphur, chlorine and/or nitrogen bound organic compounds.

The mild gasification process may be performed by contacting the pellets of the solid biomass feed with an oxygen comprising gas and wherein the amount of oxygen is preferably between 0.1 and 0.3 mass oxygen per mass biomass.

Steps (a) to (d) is preferably performed as a continuous process wherein the solid torrefied biomass is continuously or intermittently fed to the reactor to perform step (a). The temperature may be maintained at the required level by the heat of reaction in step (a) and by the temperature of the added oxygen and optional steam. The temperature may also be maintained by indirect heat exchange via heating surfaces as present in the reactor. The oxygen comprising gas, suitably in admixture with steam, as supplied to the reactor is preferably heated before being supplied to the reactor. The temperature of the oxygen comprising gas as supplied to the reactor may be between 100 and 500 °C and wherein the temperature is so chosen that water is present as steam at the chosen pressure.

The solid torrefied biomass feed is suitably supplied to the reactor as torrefied chips and/or compressed particles of a powder of a torrefied biomass as described above. A preferred reactor to be used in combination with such a chips and/or compressed particle feed is a an elongated and substantially horizontally positioned furnace having an inlet for solid torrefied biomass at one end and an outlet for the gaseous fraction and an outlet for the solid char at its opposite end. The outlet for the gaseous fraction is fluidly connected to the upstream part of the transfer conduit. In the process the solid torrefied biomass is added to the inlet for solid torrefied biomass and the gaseous fraction is continuously and solid char is continuously or intermittently discharged from the reactor via the outlet for the gaseous fraction and an outlet for the solid char respectively. In this way step (b) is performed within the reactor.

The reactor preferably has means to continuously mixing and transport the solids in the reactor from the inlet to the outlet for the solid char. The means to move the biomass solids along the length of the reactor may be by means of a rotating wall and/or by rotating means within the furnace. In case of a rotating wall a rotary kiln furnace may be used as for example described in DE19720417 and US5769007. Preferably a tubular elongated reactor is used having rotating means within the reactor. Such rotating means may be an axle positioned axially in the tubular reactor provided with radially extending arms which move the biomass axially when the axle rotates. More preferably such a reactor is further provided with three or more means to supply the oxygen comprising gas, preferably in admixture with steam, along the length of the elongated reactor and between the solids inlet and solids outlet. These means are suitably injection nozzles. These inlets for gas are axially spaced apart. The inlets are not necessarily positioned in one line but may also be positioned at different radial positions along the lower half of a tubular reactor. In the process according to the invention it is therefore preferred to supply the oxygen comprising gas to the elongated reactor at two or more axially spaced apart positions along the length of the reactor between the solids inlet and the solids outlet.

The temperature conditions in such a reactor described above may be achieved by a combination of indirect heat exchange and direct heat exchange. Indirect heat exchange may be achieved by means of flue gasses running through heating pipes or a heating mantle. Direct heat exchange may be achieved by the partial oxidation of part of the gaseous fraction and/or the char particles as generated in the process and by using a steam and oxygen mixture having an elevated temperature. Preferably only direct heat exchange is used in combination with an insulated reactor.

The solid char as produced in step (a) are separated in step (b) from the gaseous fraction for example in the reactor as described above. To avoid condensation of hydrocarbons the separation is performed at a temperature of above 450 °C and preferably at the temperature and pressure conditions of step (a). Because the solid char as produced is relatively large no special measures are required to separate the char from the gaseous fraction. Such a separation may be performed by means of simple gravitational forces.

The gaseous fraction as obtained in step (b) is supplied to an inlet of the transfer conduit. This inlet is suitably at a wall of the reactor in which steps (a) and (b) are performed. This inlet may be at the end of the reactor at which also the solids outlet is present.

In step (c) the gaseous fraction is transferred via the transfer conduit having an upstream part at the mild gasification reactor and a downstream end fluidly connected to the partial oxidation reactor. Oxygen is added to the gaseous fraction as it is transferred via the transfer conduit to combust part of the combustible components such that the temperature of the gaseous fraction in the transfer conduit is maintained above the condensation temperature of the organic compounds. This condensation temperature is the temperature at which the organic compounds having the highest condensation temperature start to condensate. Preferably the temperature of the gaseous fraction in the transfer conduit is maintained above 450 °C. It has been found that above that temperature no substantial condensation and thus fouling of the transfer conduit takes place. Preferably the temperature of the gaseous fraction in the transfer conduit is between 450 and 500 °C. The combustible components in the gaseous fraction are the organic compounds, hydrogen and carbon monoxide. The amount of oxygen added to the transfer conduit will therefore be limited to an amount required to maintain the temperature conditions and is suitably not more in order to avoid a loss in the downstream synthesis gas yield. Suitably the amount of oxygen added to the transfer conduit is controlled by measuring the temperature of the gaseous fraction in the transfer conduit and adjusting the amount of oxygen added depending on the measured temperature value.

The transfer conduit is suitably a tubular insulated transfer conduit. The transfer conduit may have a bricked internal surface. The oxygen is suitably added to the gaseous fraction via one or more nozzle present on the transfer conduit. The number of nozzles and location of the nozzles depend on the length of the transfer conduit. A longer transfer conduit may for example require several nozzles located along the length of the transfer conduit. The transfer conduit preferably has a length as short as possible and involves a minimum of bends. The transfer conduit fluidly connects the reactor of step (a) and the apparatus in which step (d) is performed.

The oxygen is suitably added to the gaseous fraction in the transfer conduit in admixture with nitrogen, carbon dioxide and/or steam. Such an added gas is preferred to protect the nozzles through which the oxygen is added. Preferably oxygen is added in admixture with steam. More preferably oxygen may be added in the same composition as the oxygen/steam used in the mild gasification of step (a).

In step (d) the gaseous fraction is subjected to a partial oxidation. Partial oxidation is another term used for gasification. This term is used in this context to differentiate the partial oxidation of step (d) from the mild gasification of step (a). Step (d) is performed such that gaseous fraction is subjected to a partial oxidation at a temperature of between 1000 and 1600 C and preferably between 1100 and 1600 C, more preferably between 1200 and 1500 °C, and at a residence time in the range of seconds and , more preferably at a residence time of less than 3 seconds. The residence time is the average gas residence time in the partial oxidation reactor. The partial oxidation is performed by reaction of oxygen with the organic compounds as present in the gaseous fraction, wherein a sub-stoichiometric amount of oxygen relative to the combustible matter as present in the gaseous fraction is used.

In the partial oxidation the C1 and higher hydrocarbons and possible oxygenates as present in the gaseous fraction are mainly converted to hydrogen and carbon monoxide thereby obtaining a syngas containing no or almost no tars.

Because slag forming compounds as may be present in the solid torrefied biomass feed remain in the solid char and because step (d) is performed in the absence of this solid char no slag will form at the elevated temperature conditions of step (d).

The oxygen used in step (d) may be mixed with steam. Preferably no steam is present. The purity of the oxygen may be as described above. Suitably oxygen is supplied as part of an oxygen comprising gas having an oxygen content of at least 90 vol%, more preferably at least 94 vol%, wherein nitrogen, carbon dioxide and argon may be present as impurities. The oxygen comprising gas used is suitably the same oxygen comprising gas as used in step (a) for practical reasons and may be obtained by the processes referred to earlier.

The total amount of oxygen fed to a mild gasification and to the partial oxidation of the gaseous fraction is preferably between 0.1 and 0.6 mass oxygen per mass biomass as fed to the mild gasification and more preferably between 0.2 and 0.5 mass oxygen per mass biomass as fed to the mild gasification.

A suitable partial oxidation process is for example the Shell Gasification Process as described in the Oil and Gas Journal, September 6, 1971 , pp. 85-90. In such a process the gaseous fraction and an oxygen comprising gas is provided to a burner placed at the top of a vertically oriented reactor vessel. Publications describing examples of partial oxidation processes are EP291111 , WO9722547, WO9639354 and WO9603345. Preferably step (d) is performed in a reactor having at one end a dome shaped and bricked internal wall. At the centre of the dome the outlet or downstream end of the transfer conduit is suitably connected. This allows the gaseous fraction to be injected into the reactor along the centre line of the reactor. In the dome several injection nozzles for supplying oxygen, suitably the oxygen comprising gas, are present. The number of nozzles will depend on the size of the reactor and this number may range from 2 to 20. Such nozzles may be water cooled metal nozzles or ceramic nozzles. Such a reactor is preferred such to perform step (d) wherein the gaseous fraction is transferred via the transfer conduit to a dome shaped part of the partial oxidation reactor to which dome shaped part oxygen is separately supplied via one or more separate inlet conduits.

The invention is therefore also directed to a partial oxidation reactor having a bricked cylindrical internal wall and a bricked dome shaped wall at an axial first end of the bricked cylindrical inner wall and wherein the bricked dome shaped wall is provided with an inlet for a hydrocarbon comprising feed at the centre of the bricked dome shaped wall and which inlet is directed along the tubular axis, and 2 to 20 injection nozzle for an oxygen comprising gas as present in the bricked dome shaped wall and directed to the tubular axis, and wherein nearer to a second end of the bricked cylindrical inner wall a gas outlet is present in the bricked cylindrical internal wall.

The invention is also directed to a process configuration suited to perform the process according to the invention and illustrated in Figure 1 comprising a tubular elongated reactor (1 ), provided with rotating means (2) within the reactor (1 ), two or more means, suitably nozzles (3), to supply oxygen to reactor (1 ), an inlet (4) for a solid torrefied biomass feed at one end (5) of the elongated reactor (1) and an outlet (6) for a solid char and an outlet (7) for a gaseous fraction at the other end (8) of the elongated reactor (1); a transfer conduit (9) fluidly connected to the outlet (7) for a gaseous fraction and provided with one or more nozzles (10) for adding oxygen to the gaseous fraction which in use flows through the transfer conduit (9), and a partial oxidation reactor (11 ) provided with an inlet (12) for a gaseous fraction fluidly connected to a downstream end (13) of transfer conduit (9) and inlet means (14) for oxygen and an outlet (15) for a synthesis gas.

The nozzles (3) are preferably axially and radially spaced apart along the length and the radius of the elongated reactor (1 ). The rotating means (3) may be an axle (16) positioned axially in the reactor (1 ) provided with radially extending arms (17) which move and mix the biomass axially when the axle rotates. The inlet (4) for a solid torrefied biomass feed is connected to a sluicing system (18) to be able to add the solids when the reactor. The outlet (6) for a solid char is connected to a sluicing system (19) to be able to discharge the solids from reactor (1).

The figure illustrates how the separation of the solid char and the gaseous fraction is achieved in the reactor. The solid char is moved to outlet (6) where it falls down towards sluicing system (19) and the gaseous fraction is discharged from reactor (1 ) via outlet (7) where it enter transfer conduit (9). In the Figure transfer conduit (9) is provided with two nozzles (10) for adding oxygen.

The figure shows the partial oxidation reactor (11 ) of this invention in a vertical orientation having a bricked cylindrical internal wall (23) and a bricked dome shaped wall (20) at an axial first end of the bricked cylindrical inner wall (23). The reactor may also be oriented in a horizontal orientation. The bricked dome shaped wall (20) is provided with an inlet (12) for a hydrocarbon comprising feed, such as the gaseous fraction of the invented process, at the centre of the bricked dome shaped wall (20). This inlet (12) is directed along the tubular axis or centre line (21 ). Four injection nozzles (22) are shown for an oxygen comprising gas as present in the bricked dome shaped wall (20) as the oxygen comprising gas as inlet means (14). The injection nozzles (22) are directed to the tubular axis (21 ). At a second end of the bricked cylindrical inner wall (23) a gas outlet (15) is present in the bricked cylindrical internal wall (23). Such a reactor may be used for partial oxidation of various feeds and preferably in the process of this invention.

Claims

1 . Process to prepare synthesis gas comprising carbon monoxide and hydrogen from a solid torrefied biomass feed by a process comprising the following steps

(a)subjecting the solid torrefied biomass to a mild gasification in a reactor to obtain a gaseous fraction comprising hydrogen, carbon monoxide and a mixture of gaseous organic compounds and a solid char,

(b) separating the gaseous fraction from the solid char,

(c) transferring the gaseous fraction via a transfer conduit having an upstream part at the mild gasification reactor and a downstream end fluidly connected to a partial oxidation reactor and wherein oxygen is added to the gaseous fraction as it is transferred via the transfer conduit to combust part of the combustible components such that the temperature of the gaseous fraction in the transfer conduit is maintained above the condensation temperature of the gaseous organic compounds, and

2. Process according to claim 1 , wherein oxygen is added to the gaseous fraction in step (c) in admixture with nitrogen, carbon dioxide and/or steam.

3. Process according to any one of claims 1-3, wherein the temperature of the gaseous fraction in the transfer conduit is preferably between 450 and 500 °C.

4. Process according to any one of claims 1-3, wherein the mild gasification is performed at a temperature of between 500 and 800 °C and at a solid residence time of between 10 and 80 minutes. Process according to claim 4, wherein the mild gasification reactor is an elongated and substantially horizontally positioned furnace having an inlet for solid torrefied biomass at one end and an outlet for the gaseous fraction and an outlet for the solid char at its opposite end and wherein the outlet for the gaseous fraction is fluidly connected to the upstream part of the transfer conduit and wherein solid torrefied biomass is added to the inlet for solid torrefied biomass and wherein the gaseous fraction and solid char are continuously discharged from the reactor via the outlet for the gaseous fraction and an outlet for the solid char respectively. Process according to any one of claims 1-5, wherein the mild gasification is performed in the presence of oxygen and wherein the amount of oxygen as supplied to the mild gasification reactor is between 0.1 and 0.3 mass oxygen per mass biomass as supplied to the mild gasification reactor. Process according to claim 6, wherein also H2O as super heated steam is added to the mild gasification reactor and wherein the content of oxygen is between 20 and 40 vol.% O2 per combined O2 and H2O. Process according to claim 7, wherein the oxygen as added in step (c) has the same composition as the oxygen supplied to the mild gasification reactor in step (a). Process according to any one of claims 1-8, wherein the solid torrefied biomass feed has a content of volatiles is between 50 and 75 wt%, has an atomic hydrogen over carbon (H/C) ratio of between 1 and 1 .2 and an atomic oxygen over carbon (O/C) ratio of between 0.4 and 0.6. Process according to any one of claims 1 -9, wherein the solid torrefied biomass are torrefied chips and/or compressed particles of a powder of a torrefied biomass. 15

11 . Process according to any one of claims 1 -10, wherein in the mild gasification the hydrogen over carbon (H/C) ratio is reduced by more than 70% and the atomic oxygen over carbon (O/C) ratio is reduced by more than 80% when comparing the solid torrefied biomass and the solid char.

12. Process according to any one of claims 1-11 , wherein the solid torrefied biomass is increased in pressure in a sluicing system before being added to the mild gasification reactor.

13. Process according to any one of claims 1-12, wherein the gaseous fraction is transferred via the transfer conduit to a dome shaped and bricked part of the partial oxidation reactor to which dome shaped part oxygen is separately supplied via one or more separate inlet conduits.

14. Process according to any one of claims 1-13, wherein the partial oxidation is performed at a temperature of between 1000 and 1600 °C.

15. Process according to any one of claims 1 -14, wherein the total amount of oxygen fed to steps (a), (c) and (d) is between 0.1 and 0.6 mass oxygen per mass of solid torrefied biomass as fed to the mild gasification in step (a).

16. A partial oxidation reactor having a bricked cylindrical internal wall and a bricked dome shaped wall at an axial first end of the bricked cylindrical inner wall and wherein the bricked dome shaped wall is provided with an inlet for a hydrocarbon comprising feed at the centre of the bricked dome shaped wall and which inlet is directed along the tubular axis, and 2 to 20 injection nozzle for an oxygen comprising gas as present in the bricked dome shaped wall and directed to the tubular axis, and wherein nearer to a second end of the bricked cylindrical inner wall a gas outlet is present in the bricked cylindrical internal wall. 16 A process configuration comprising a tubular elongated reactor (1 ), provided with rotating means (2) within the reactor (1 ), two or more means, suitably nozzles (3), to supply oxygen to reactor (1 ), an inlet (4) for a solid torrefied biomass feed at one end (5) of the elongated reactor (1 ) and an outlet (6) for a solid char and an outlet (7) for a gaseous fraction at the other end (8) of the elongated reactor (1 ); a transfer conduit (9) fluidly connected to the outlet (7) for a gaseous fraction and provided with one or more nozzles (10) for adding oxygen to the gaseous fraction which in use flows through the transfer conduit (9), and a partial oxidation reactor (11) provided with an inlet (12) for a gaseous fraction fluidly connected to a downstream end (13) of transfer conduit (9) and inlet means (14) for oxygen and an outlet (15) for a synthesis gas. A process configuration according to claim 16, wherein the partial oxidation reactor is a partial oxidation reactor according to claim 16. Process according to any one of claims 1-15 as performed in a process configuration according to any one of claims 17-18.