WO2016016253A1

WO2016016253A1 - Integrated short contact time catalytic partial oxidation/gas heated reforming process for the production of synthesis gas

Info

Publication number: WO2016016253A1
Application number: PCT/EP2015/067292
Authority: WO
Inventors: Luca Eugenio Basini
Original assignee: Eni SpA
Current assignee: Eni SpA
Priority date: 2014-07-29
Filing date: 2015-07-28
Publication date: 2016-02-04
Anticipated expiration: 2017-01-29

Abstract

This invention relates to an integrated process for the production of synthesis gas comprising the following stages: a) dividing a gaseous hydrocarbon stream, preferably comprising natural gas and/or refinery gas, into a first and a second stream, b) mixing the said second stream with a stream containing oxygen, water vapour and possibly CO₂, and possibly a third stream containing liquid and/or gaseous compounds in which the said gaseous compounds are selected from hydrocarbons other than natural gas and/or refinery gas, or from those compounds which also derive from biomass, and in which the said liquid compounds are selected from hydrocarbons or compounds of various nature deriving from biomass, or mixtures thereof, c)causing the mixture obtainedin (b) to react in a short contact time Catalytic Partial Oxidation section to form a first synthesis gas, d) causing the first gaseous stream, preferably selected from natural gas and/or refinery gas, to react with steam in a Gas Heated Reforming section to produce a second synthesis gas, and convectively heating the Gas Heated Reforming reactor with the first synthesis gas obtained in the short contact time Catalytic Partial Oxidation section.

Description

INTEGRATED SHORT CONTACT TIME CATALYTIC PARTIAL OXIDATION/GAS HEATED REFORMING PROCESS FOR THE PRODUCTION OF SYNTHESIS GAS

DESCRIPTION

This invention relates to a process for the production of synthesis gas through a process integrating short contact time Catalytic Partial Oxidation (CPO) technology with Gas Heated Reforming (GHR) technology.

In this patent application all the operating conditions reported in the text are to be understood to be preferred conditions even if that is not expressly stated.

For the purposes of this description the terms "comprises" or "includes" also comprise the terms "consists of" or "essentially consists of".

For the purposes of this description the definitions of intervals always include the end members unless specified otherwise.

Synthesis gas is produced by Steam Reforming (SR) technology and by Non-catalytic Partial Oxidation (POx) and Autothermal Reforming (ATR) technologies. A relatively recent variant of the SR process is Gas Heated Reforming (GHR) which at least partly replaces the radiant heat required for the endothermic reactions with a convective source: typically the hot gas produced by combustion reactions and/or the synthesis gas itself produced by an ATR at high temperature. In some cases the ATR and SR or GHR technologies are integrated into schemes known as Combined Reforming (CR).

The characteristics of the abovementioned technologies are described in numerous documents in the literature, among which we would cite:

1 ) "Technologies for large-scale gas conversion" Aasberg-Petersen, K., Bak Hansen, J. -H., Christensen, T. S., Dybkjaer, I., Christensen, P. Seier, Stub Nielsen, C, Winter Madsen, S. E. L, Rostrup-Nielsen, J. R., Applied Catalysis A: General, 221 (1 -2), p.379, Nov 2001 ; 2) "Synthesis Gas production by Steam Reforming", Dybkjaer, lb; Seier Christtensen P.; Lucassen Hansen V.; Rostrup-Nielsen J.R., EP1097105A1 ;

3) J.R. Rostrup-Nielsen, J. Sehested and J.K. Noskov, Adv. Catal. 47 (2002), pp. 65- 139;

4) "Catalytic Steam Reforming"; Rostrup-Nielsen J.R.; pp 1 -1 17, Catalysis Vol. 5, Edited by John R. Anderson and Michel Boudart,

5) "Issues in H₂ and synthesis gas technologies for refinery, GTL and small and

distributed industrial needs"; Basini, Luca, Catalysis Today, 106 (1 -4), p.34, Oct 2005.

Short Contact Time - Catalytic Partial Oxidation (SCT-CPO) technology is also described in many documents in the literature among which we would cite:

WO 2011 151082, WO 2009065559, WO 201 1072877, US 2009127512, WO

2007045457, WO 2006034868, US 200521 1604, WO 2005023710, DE 10232970, WO 9737929, EP 0725038, EP 0640559 and L.E. Basini and A. Guarinoni, "Short Contact Time Catalytic Partial Oxidation (SCT-CPO) for Synthesis Gas Processes and Olefins Production", Ind. Eng. Chem. Res. 2013, 52, 17023-17037.

Synthesis gas is used in many industrial processes, among which we would mention the synthesis of ammonia and urea, the production of H₂ for refining and fuels production, the synthesis of methanol and its derivatives, and the synthesis of liquid hydrocarbons by the Fischer-Tropsch (F-T) process. Synthesis gas is also used in fine chemical processes, and in the electronics, metal refining, glass and food industries. These many industrial uses require the synthesis gas is produced with very different compositions in order to minimize recycling and improve overall yields.

Table 1 describes the main reactions involved in the processes for the production of synthesis gas and Table 2 shows the compositional characteristics of the synthesis gas required by their main uses.

Table 1

Steam - CO₂ Reforming

CH₄ + H₂0 = CO + 3 H₂ 206

CO + H₂0 = C0₂ + H₂ -41

CH₄ + C0₂ = 2CO + 2 H₂ 247

Non-Catalytic Partial Oxidation (POx)

CH₄ + 3/2 0₂ = CO + 2 H₂0 -520 [4]

CO + H₂0 = C0₂ + H₂ -41 [5]

Autothermal Reforming (ATR)

CH₄ + 3/2 0₂ = CO + 2 H₂0 -520

CH₄ + H₂0 = CO + 3 H₂ 206

CO + H₂0 = C0₂ + H₂ -41

Catalytic Partial Oxidation (CPO)

CH₄ + ½ 0₂ = CO + H₂ 38

CO + H₂0 = C0₂ + H₂ 41

Table 2

EP 2142467 describes a combined process in which a gaseous hydrocarbon mixture reacts with steam in an endothermal adiabatic pre-reformer and the product, the pre- reformate, is divided into three streams fed to a Steam Methane Reformer (SMR), a Gas Heated Reformer (GHR) and an Autothermal Reformer (ATR) operating in parallel. EP 1622827 describes a process for the production of synthesis gas from carbon- containing material, preferably comprising natural gas or gaseous hydrocarbon feedstock, refinery gas and more generally gas streams containing compounds having up to 4 carbon atoms, which provides for: (a) a stage of partial oxidation of the carbon-containing material performed in a reactor in which a burner is present in the upper part (therefore an ATR or POx reactor) thus obtaining a first mixture of hydrogen and carbon monoxide;

(b) a stage of catalytic Steam Reforming of the carbon-containing material in a tubular Convective Steam Reforming (CSR) Reactor, in which the tubes contain a catalyst and in which the molar ratio between steam and carbon is less than 1 , to separately produce a second product;

(c) feeding the product obtained in (b) to the top of a partial oxidation reactor to mix it with that obtained in (a);

(d) using the mixture obtained in (d) to provide heat to the CSR.

These conditions result in producing a stream of synthesis gas in the CSR at relatively low temperatures and with a high residual methane content (between 5-30% mole/mole). EP 1403216 describes a process for the production of synthesis gas in which a series of catalytic steam reforming units are in parallel with an AutoThermal Reforming unit. The heat required by the SR passages is again in this case provided by combustion of the outflows from the various SR and ATR. The final mixture of outflows obtained by adding the synthesis gas produced by the convectively heated SR processes and ATR processes has an H₂/CO ratio of between 1 .8 and 2.3 v/v.

WO 2008017741 describes a process for the production of liquid hydrocarbons from biomass, coal, lignite and petroleum residues boiling at a temperature over 340°C, the said process comprising at least:

a stage of partial oxidation of the heavy feedstocks in the presence of oxygen to produce a first synthesis gas, which may be purified, which has an H₂/CO ratio of less than 1 ;

a stage of Steam Reforming of the light feedstocks having at least 10 carbon atoms for the production of a second synthesis gas, which may be purified, having a H₂/CO ratio of more than 3;

a Fischer-Tropsch (FT) stage to convert the synthesis gas formed by mixing at least part of the first and second synthesis gases in proportions such that H₂/CO lies between 1.2 and 2.5;

a stage of hydrocracking of at least one portion of the hydrocarbons produced by FT boiling above 150°C in which the light hydrocarbons produced in FT have fewer than 10 carbon atoms.

Adiabatic endothermic "pre-reforming" reactors are often inserted upstream of the SR and ATR reactors. These reactors are described in various documents in the literature, including "T.S. Christensen, Appl. Catal. A: 138(1996)285" e "I. Dybkjaer, Fuel Process. Techn. 42(1995)85". The "pre-reformers" make it possible to convert the C2+ carbons present in the gaseous hydrocarbon streams into CO, H₂ and CH₄ at relatively low temperatures (approximately 550°C), reducing the possibility of the occurrence of other parasitic formation reactions [7-9] in the subsequent passes through SR or ATR. In particular reactions [10-1 1] which accompany the Water Gas Shift (WGS) reaction [5] take place in the endothermic "pre-reforming" reactors.

C_nH_m = nC + m/2H₂ ΔΗ^ο>0 [7]

CH₄ = C + 2H₂ ΔΗ°= 75 kJ/mole [8]

2CO = C + C0₂ ΔΗ°= -173 kJ/mole [9]

C_nH_m + nH₂0 = nCO + (n+m/2)H₂ ΔΗ^ο>0 [10]

CO + 3H₂ = CH₄ + H₂0 AH°=-206kJ/mole [11]

CO + H₂0 = C0₂ + H₂ AH°=-41 kJ/mole [5]

The adiabatic endothermic "pre-reforming" reactors are typically fed with a mixture of gaseous reagents and steam preheated in a furnace at approximately 550°C. A catalyst based on Ni is (in most cases) used to complete reactions [10-11 ] in the adiabatic endothermic "pre-reforming" reactor. The mixture of pre-reformed gas is then passed to the reforming reactor and has lesser thermodynamic affinity towards the reactions forming carbon-containing residues through reactions [7-9]. This makes it possible to reduce the steam/carbon (Steam/C v/v) and/or Oxygen/Carbon (O2/C) ratios in the feeds to the SR or ATR reactors, increasing their energy efficiency (W.D. Verduijin Ammonia Plant Saf. 33(1993)165). The use of "pre-reforming" units also makes it possible to increase the flexibilities of SR and ATR technologies in relation to the composition of the feedstock; for example it makes it possible to use feedstocks from refinery gases to naphthas. Finally the use of adiabatic endothermic "pre-reforming" technology can increase the production capacity of plants without requiring significant changes in the characteristics of the reforming unit. As already mentioned, the technologies for the production of synthesis gas are used in many industrial processes to produce different products. It is therefore desirable to be able to have a process for the production of synthesis gas which is flexible with regard to both the composition of the reagent feedstock, production capacity, and the quality of the synthesis gas produced. At the same time it is very important to use processes having high energy efficiency with low carbon dioxide emissions, which require smaller capital costs than conventionally used technologies.

With this object this patent application provides an integrated process for the production of synthesis gas which combines Short Contact Time Partial Catalytic Oxidation (SCT- CPO) technology with Gas Heated Reforming (GHR) technology.

The object of this invention therefore comprises an integrated process for the production of synthesis gas comprising the following stages:

a) dividing a gaseous hydrocarbon stream, preferably comprising natural gas and/or refinery gas, into a first and a second stream,

b) mixing the said second stream with a stream containing oxygen, steam and

possibly C0₂, and possibly a third stream containing liquid and/or gaseous compounds in which the said gaseous compounds are selected from hydrocarbons other than natural gas and/or refinery gas or from those compounds which also derive from biomass, and in which the said liquid compounds are selected from hydrocarbons or compounds of various nature deriving from biomass, or mixtures thereof,

c) causing the mixture obtained in (b) to react in a short contact time Partial Catalytic Oxidation section to form a first synthesis gas,

d) causing the first gaseous stream, preferably selected from natural gas and/or refinery gas, to react with steam in a Gas Heated Reforming section to produce a second synthesis gas, convectively heating the Gas Heated Reforming reactor with the first synthesis gas obtained from the short contact time Partial Catalytic Oxidation section.

This configuration therefore makes use of the possibility offered by SCT-CPO technology to use different types of feedstocks, both liquid and gaseous, which cannot be used in GHR technologies, maintaining the high energy efficiency characteristics of catalytic conversions and thus using them in the production of synthesis gas. This process configuration therefore consider a scheme in which the SCT-CPO stage and a GHR stage operate in a parallel in such a way as to allow the use of compounds which GHR technology is incapable of converting for the production of synthesis gas, in particular liquid and gaseous hydrocarbons, and compounds deriving from biomass which are also mixed together which cannot be used in either SR processes or ATR processes.

Although POx technology is capable of dealing with quite a broad range of feedstocks, its energy consumption is higher in that its non-catalytic reactions are less selective and take place at temperatures of 300°C-600°C, which are higher than the temperatures envisaged for catalytic technologies, and in particular SCT-CPO technology which uses neither a burner nor a combustion chamber.

The integrated process to which this patent application relates offers the following advantages:

I. increasing the flexibility of catalytic processes for the production of synthesis gas making it possible to use of gaseous and liquid hydrocarbons and compounds deriving from biomass in combination,

II. increasing the compositional flexibility of the synthesis gas produced for optimum integration with the processes using it, such as for example the processes of: a) production of NH₃/urea, b) production of H₂ for refining and for other various uses (metals refining, glass, electronics, food industries, etc.), c) the production of methanol and its derivatives, d) Fischer-Tropsch synthesis for GTL conversions, and e) hydroformylation and fine chemicals processes.

III. improving the overall energy efficiency of synthesis gas production and use

systems, thus reducing "greenhouse gas" emissions and possibly removing and reusing most of the C0₂ produced,

IV. construction of plants having high production capacity,

V. reducing the capital costs of "via-synthesis gas" systems,

VI. debottlenecking production capacity in existing plants.

Further objects and advantages of this invention will be more clear from the following non-limiting descriptions and appended figures provided purely by way of example. Figures 1-6 describe preferred embodiments of this invention and will be described in detail below. DETAILED DESCRIPTION

This patent application relates to an integrated process for the production of synthesis gas comprising the following stages:

b) mixing the said second stream with a stream containing oxygen, steam and

possibly C0₂, and possibly a third stream containing liquid and/or gaseous compounds in which the said gaseous compounds are selected from hydrocarbons other than natural gas and/or refinery gas, or from those compounds which also derive from biomass, and in which the said liquid compounds are selected from hydrocarbons or compounds of various nature deriving from biomass, or mixtures thereof,

The stream containing oxygen may be oxygen, air or enriched air.

In a preferred embodiment this process provides for a further pre-reforming stage upstream of either the SCT-CPO section, or the GHR section, or both.

In a preferred embodiment the said pre-reforming stage may be either exothermic adiabatic or endothermic adiabatic, and in particular the following combinations are described here: adiabatic exothermic pre-reformer upstream of the GHR and upstream of the SCT- CPO, or

adiabatic endothermic pre-reformer upstream of the GHR and upstream of the SCT-CPO, or

adiabatic exothermic pre-reformer upstream of the GHR and adiabatic endothermic pre-reformer upstream of the SCT-CPO, or

adiabatic endothermic pre-reformer upstream of the GHR and adiabatic exothermic pre-reformer upstream of the SCT-CPO.

The first and second hydrocarbon gas streams, preferably selected from natural gas and/or refinery gas, may be fed to either an adiabatic exothermic pre-reformer or an adiabatic endothermic pre-reformer. This is regardless of the fact whether these pre- reformers are upstream of either the GHR or the SCT-CPO.

The third stream containing gaseous compounds, in which the said gaseous compounds are selected from hydrocarbons other than natural gas and/or refinery gas or from gaseous compounds which can also be obtained from biomass, can be fed to either an adiabatic exothermic pre-reformer or an adiabatic endothermic pre-reformer located upstream of a SCT-CPO.

The third stream containing liquid compounds in which the said liquid compounds are selected from hydrocarbons or compounds of various nature deriving from biomass, or mixtures thereof, may be fed to only one adiabatic exothermic pre-reformer located upstream of a SCT-CPO.

When the third stream contains both liquid compounds and gaseous compounds these can be fed to only one adiabatic exothermic pre-reformer located upstream of a SCT- CPO.

The pre-reforming stage gives rise to a flow of reformate which is subsequently fed to the SCT-CPO and/or GHR sections.

An adiabatic exothermic pre-reforming reactor benefits from the same principles as the SCT-CPO process as described for example in ITMI20120418.

The pre-reforming sections may be separate and each located upstream of the GHR and SCT-CPO sections.

According to a preferred embodiment of this invention the first and second synthesis gases are cooled through a heat exchanger device generating steam.

Preferably the steam generated is used as a reagent in either the Gas Heated Reforming section or the short contact time Partial Catalytic Oxidation section. The excess steam is instead used for external purposes (export steam).

If the first gaseous stream selected from natural gas and/or refinery gas contains sulfur compounds, then this may undergo a hydrodesulfurisation treatment before being passed to the pre-reformer sections or to the GHR and SCT-CPO sections.

According to a preferred embodiment of this invention the product containing H₂ and CO obtained after reaction in the GHR and SCT-CPO sections may be used for the synthesis of liquid hydrocarbons by the Fischer-Tropsch process, or for the synthesis of methanol, or for the synthesis of ammonia.

The integrated process described and claimed may also provide for a stage in which the first and second synthesis gases are reacted, after cooling, according to a water gas shift (WGS) reaction, followed by a stage of separation or purification for the production of H₂. Industrial solutions incorporating SCT-CPO processes, GHR processes and methanol synthesis benefit from the advantage deriving from the integration between GHR and SCT-CPO technology, which makes it possible to avoid the excess hydrogen production that occurs when only GHR technology is used.

Commonly, by utilizing only the GHR technology and natural gas, the produced mixture of hydrogen and carbon monoxide would have an H₂/CO ratio greater than 3 v/v, preferably over 3.5 v/v, and in addition to this it would be difficult to reduce the values for methane residue in the "dry" synthesis gas (that is without steam) produced by GHR technology alone below 3% v/v. If therefore a single GHR reactor is used to produce synthesis gas for the synthesis of methanol, it would be obtained a mixture having an H₂ content (approximately 30% of the hydrogen produced would be superfluous) and a CH₄ content which it would be desirable to reduce in order to improve the energy efficiency of the whole system

Thanks to the integrated process according to the present invention, it is instead possible to obtain a hydrogen and carbon monoxide mixture in which the H₂/CO ratio lies between 1.8 and 3.5 v/v; this improves the efficiency of the methanol synthesis process because it reduces the volume of the recycling loop in the MeOH synthesis and the purge of H₂ and CH₄. The greater efficiency of the system for producing and using synthesis gas also makes it possible to reduce C0₂ emissions.

More particularly the possibility of modulating C0₂ production together with the value of the H₂/CO ratio makes it possible, according to the technical solution of the present invention, to maintain the "methanol modulus" value (Stoichiometric Number SN) close to 2 and to optimize the per pass conversion through the synthesis reactors, avoiding the purging of H₂.

The methanol modulus is defined by the equation:

2 - C0₂

(v/v)

CO ~f~ C £?2

Industrial solutions which incorporate processes of the SCT-CPO type, GHR processes and Fischer-Tropsch syntheses as illustrated in this patent application have the advantage that they make it possible to recover the heat of reaction produced by catalytic partial oxidation reactions. This advantage is particularly notable and advantageous in the case of medium capacity Gas To Liquid (GTL) plants and in particular in contexts where it is not possible to utilise export steam, and in situations in which energy efficiency is an important parameter for determining the economic viability of the process.

In particular it is pointed out that the solution described and claimed in the present patent application reduces by up to 40% the carbon dioxide emissions generated in the furnaces for pre-heating the reagents in comparison to the cases in which synthesis gas production is obtained using ATR technology.

In the process configuration which is most widespread in the state of the art, NH₃ is produced by feeding to a SR reactor desulfurised natural gas mixed with steam. The synthesis gas so produced is passed to a "secondary reformer", typically an ATR which uses air as oxidant. The synthesis gas obtained contains H₂, CO, N₂, C0₂ and a small CH₄ residue (typically less than 1% on a volumetric basis). This mixture then undergoes WGS treatment in which CO is almost completely converted into C0₂ and H₂. The subsequent stage provides for cooling the synthesis gas after WGS and removing the C0₂ (typically by "chemical scrubbing" with amine). Finally the stream obtained in this way is passed to a "methanator" in which the C0₂ and the residual CO are converted into CH₄. The mixture so obtained, which mainly contains H₂ and N₂ in a ratio of

approximately 3 v/v, is cooled, compressed and passed to an NH₃ synthesis reactor. In the synthesis of urea the C0₂ removed by chemical scrubbing is compressed (12-40 MPa) and added to NH₃, producing carbamate and urea (H₂NC0NH₂) at a T of between 150 and 250°C. When NH₃ synthesis is dedicated to urea production this configuration gives rise to a quantity of C0₂ which is not sufficient to maximise the yields from this process. This technological solution can therefore be improved if processes which integrate GHR technology in parallel with SCT-CPO technology are used. Using these arrangements it is in fact possible to produce synthesis gas that is suitable for the synthesis of NH₃ and therefore urea by using a GHR reactor fed with desulfurised natural gas, and to integrate the production of synthesis gas using reactors of this type with the production of synthesis gas obtained by the SCT-CPO process. As already mentioned, the latter makes it possible to use different types of gaseous and liquid hydrocarbons and possibly compounds deriving from biomass as a hydrocarbon source and also makes it possible to use air or enriched air as the oxidant. This type of integration makes it possible to both optimise the H₂/N₂ ratio and the co-production of CO₂ when NH₃ production is dedicated to urea synthesis. The co-production of C0₂ (which is in deficit in those arrangements which use SR and ATR reactors) can in fact be increased with this process configuration either by using the heavier hydrocarbons in natural gas as a feedstock or by varying the steam/carbon and 0₂ (air)/C ratios in the feed to the SCT- CPO reactors:

Figures 1-6 describe some preferred embodiments of this invention.

Figure 1 describes a process arrangement in which a first stream of refinery gas and/or natural gas, and their mixtures, (2), is desulfurised in a hydrodesulfurisation unit (6). This desulfurised stream is divided into two parts; one part is passed to a GHR after being mixed with steam (1 ) and the other part is mixed with a second mixture containing a second stream of gaseous reagents different from first stream (2) and/or liquid compounds and/or compounds deriving from biomass which cannot normally be processed in a GHR reactor but can be converted in a SCT-CPO reactor. An oxidant stream (4) and steam (5) are fed to this mixture. The first reaction product (30) leaving the SCT-CPO is passed at high temperature to the GHR reactor as a thermal vector, convectively heating it, and thus making it possible to produce synthesis gas (31 ).

Streams (30) and (31 ) are recombined and cooled in a syngas cooler (SGC) at temperatures below 400°C forming the final synthesis gas (13), generating steam which is delivered as a feed (1 , 5) or exported for other uses (1 1 , 12).

Figure 2 describes a process arrangement similar to that in Figure 1 but which includes exothermic adiabatic pre-reforming (14), for example having the characteristics as described in ITMI20120418 which make it possible to convert the heavier fraction of the feedstock fed to the SCT-CPO reactor.

Figure 3 describes a process arrangement similar to that in Figure 1 or 2 in which both the reagent mixtures are treated in pre-reforming sections, an adiabatic endothermic one (15) and an adiabatic exothermic one (14) respectively, before being passed to the GHR and SCT-CPO reactors.

Figure 4 describes integration of the process according to this invention with a Fischer- Tropsch section (18). In this case the synthesis gas is produced using the arrangement in Figure 3 and passed to a F-T reactor (18) to produce a mixture of liquid and gaseous hydrocarbons having a high middle distillates content (21 ). The arrangement provides that part (20) of the "recycle loop" (19) of the FT reactor is recycled as a feed to the SCT- CPO reactor.

Figure 5 describes integration of the process according to this invention with a methanol synthesis section. In particular the synthesis gas produced following the arrangement in Figure 3 is subsequently compressed (16) and passed to a methanol synthesis reactor (17) and the methanol produced (24) is then obtained pure after distillation treatment (23).

Figure 6 describes integration of the process according to this invention with an ammonia synthesis section. In this case the synthesis gas produced by means of an arrangement described in Figure 3 undergoes Water Gas Shift treatment (25) to remove the CO₂ (26) and methanation treatment (27) before being compressed (16) and passed to the ammonia synthesis reactor (28). The streams of the Iatter (29) and C0₂ (21 ) can be obtained with the best stoichiometry for use in urea synthesis processes.

Claims

An integrated process for the production of synthesis gas which comprises the following steps:

a. dividing a gaseous hydrocarbon stream into a first and a second stream, preferably comprising natural gas and/or refinery gas,

b. mixing said second current with an oxygen containing stream, steam and possibly C0₂, and possibly a third stream containing liquid and/or gaseous compounds, in which said gaseous compounds in which said gaseous compounds are selected from hydrocarbons other than natural gas and/or refinery gas, or also among those compounds deriving from biomass, and wherein said liquid compounds are selected from hydrocarbons, or compounds of various nature deriving from biomass, or mixtures thereof, c. reacting the mixture obtained in step (b) in a short contact time Catalytic Partial Oxidation section to form a first synthesis gas,

d. reacting the first gaseous stream, preferably selected from natural gas and/or refinery gas, with steam in Gas Heated Reforming section to produce a second synthesis gas, and convectively warming the Gas Heated Reforming reactor with the first synthesis gas obtained in the short contact time Catalytic Partial Oxidation section.

A process according to claim 1 wherein there is provided a further pre-reforming step upstream of the SCT-CPO section, or the GHR section, or both sections. A process according to claim 2 wherein there is provided that the pre-reforming step can be exothermic adiabatic or endothermic adiabatic.

A process according to claim 2 wherein there is provided an exothermic adiabatic pre-reforming step upstream of a Gas Heated Reforming section and upstream of a short contact time section catalytic partial oxidation section.

5. A process according to claim 2 wherein there is provided an endothermic adiabatic pre-reforming step upstream of a Gas Heated Reforming section and upstream of a short contact time catalytic partial oxidation section.

6. A process according to claim 2 wherein there is provided an exothermic adiabatic pre-reforming step upstream of a Gas Heated Reforming section and an endothermic adiabatic pre-reforming step upstream of a short contact time catalytic partial oxidation section.

7. A process according to claim 2 wherein there is provided an endothermic adiabatic pre-reforming step upstream of a section of Gas Heated Reforming and an exothermic adiabatic pre-reforming step upstream of a short contact time catalytic partial oxidation section.

8. A process according to any one of claims 1 to 7 wherein the first and second

gaseous hydrocarbon stream, preferably selected from natural gas and/or refinery gas, can be fed to either an exothermic adiabatic pre-reformer or an endothermic adiabatic pre-reformer.

9. A process according to any one of claims 1 to 8 wherein the third stream containing gaseous compounds, wherein said gaseous compounds are selected from hydrocarbons other than natural gas and/or refinery gas or from gaseous compounds also derived from biomass, is fed to an exothermic adiabatic pre- reformer or to an endothermic adiabatic pre-reformer placed upstream of a short contact time catalytic partial oxidation section.

10. A process according to any one of claims 1 to 9 wherein the third stream containing liquid compounds, in which said liquid compounds are selected from hydrocarbons, or compounds of various nature deriving from biomass, or mixtures thereof, are fed only to an exothermic adiabatic pre-reformer placed upstream of a short contact time catalytic partial oxidation section.

1 1. A process according to any one of claims 1 to 10 wherein when the third current contains both liquid compounds and gaseous compounds, these are fed only to an exothermic adiabatic pre-reformer placed upstream of a short contact time catalytic partial oxidation section.

12. An integrated process according to any one of claims 1 to 10 wherein the first and second synthesis gases are sent to a heat exchange device to be cooled by generating steam.

13. An integrated process according to claim 12 wherein the generated steam is used as a reagent both in the Gas Heated Reforming section and in the Catalytic Partial Oxidation section.

14. A process according to any one of claims 1 to 13 wherein the first gaseous stream selected from natural gas and/or refinery gas contains sulfur compounds and is subjected to a hydro-desulfurisation treatment before being sent to the pre - reformer sections, or Gas Heated Reforming and Catalytic Partial Oxidation sections.

15. An integrated process according to any one of claims 1 to 14 wherein the cooled synthesis gas is used for the Fischer-Tropsch synthesis of liquid hydrocarbons.

16. An integrated process according to any one of claims 1 to 14 wherein the cooled synthesis gas is used for the synthesis of methanol.

17. An integrated process according to any one of claims 1 to 14 wherein the cooled synthesis gas is used for ammonia synthesis.

18. An integrated process according to any one of claims 1 to 12 wherein the first and second synthesis gas are reacted, after cooling, according to a water gas shift reaction, followed by a stage of separation or purification for H₂ production.