WO2016016257A1

WO2016016257A1 - Integrated sct-cpo/pox process for producing synthesis gas

Info

Publication number: WO2016016257A1
Application number: PCT/EP2015/067300
Authority: WO
Inventors: Luca Eugenio Basini
Original assignee: Eni S.P.A.
Priority date: 2014-07-29
Filing date: 2015-07-28
Publication date: 2016-02-04

Abstract

The present invention relates to an integrated process for producing synthesis gas from carbonaceous compounds, liquid feedstock, gaseous feedstock, or combinations thereof which comprises the step of conducting in parallel one stage of short contact time catalytic partial oxidation (SCT-CPO) and a stage of non-catalytic partial oxidation (POx).

Description

INTEGRATED SCT-CPO/POx PROCESS FOR PRODUCING SYNTHESIS GAS The present invention relates to a process for producing synthesis gas through a process that integrates Short Contact Time - Catalytic Partial Oxidation SCT-CPO technology with non-catalytic Partial Oxidation POx technology.

In the present patent application, all the operating conditions included in the text must be interpreted as preferred conditions even if this is not expressly stated. For the purpose of the present text the term "comprise" or "include" also comprises the term "consist of" or "essentially consisting of".

For the purpose of the present text the definitions of the intervals always include the extremes unless otherwise specified.

Synthesis gas is produced with Steam Reforming (SR) technology and with Non-Catalytic Partial Oxidation (POx) and AutoThermal Reforming (ATR) technology. A relatively recent variation of the SR process is Gas Heated Reforming (GHR) which at least partially replaces the radiant heat needed for endothermic reactions with a convective source: typically the hot gas produced by combustion reactions and/or the same synthesis gas produced by ATR at a high temperature. In some cases ATR and SR or GHR technologies are integrated within processes known as Combined Reforming (CR). The characteristics of the above-mentioned technologies are described in numerous documents in literature, including:

1 ) "Technologies for large-scale gas convers/on "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.; pg 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 numerous documents in literature including: WO 201 1 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 e L.E. Basini e 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 a large number of industrial processes including Ammonia and Urea synthesis, production of H₂ for refining and obtaining fuels, synthesis of Methanol and its derivatives and synthesis of liquid hydrocarbons with the Fischer-Tropsch (F-T) process. Synthesis gas is also used in fine chemical processes and in the electronic, metal refining, glass and food industries. These numerous industrial uses require the synthesis gas to be produced with very different compositions from one another so as to minimize recycling and improve overall yields.

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

Steam - C0₂ Reforming

CH₄ + H₂0 = CO + 3 H₂ [1 ] CO + H₂0 = C0₂ + H₂ [2] CH₄ + C0₂ = 2CO + 2 H₂ [3] Non-Catalytic Partial Oxidation (POx)

CH₄ + 3/2 0₂ = CO + 2 H₂0

CO + H₂Q = CQ₂ + H₂

Autothermal Reforming (ATR)

CH₄ + 3/2 0₂ = CO + 2 H₂0 -520 [4] CH₄ + H₂0 = CO + 3 H₂ 206 [1 ]

CO + H₂Q = CQ₂ + H₂ -41 [5]

Catalytic Partial Oxidation (CPO)

CH₄ + ½ 0₂ = CO + H₂

CO + H₂0 = C0₂ + H₂

Table 2

EP 2142467 describes a combined process in which a gaseous hydrocarbon mixture reacts with steam in an endothermic adiabatic pre-reformer and the pre-reformed product is split into three streams fed to a Steam Methane Reformer (SMR), to a Gas Heated Reformer (GHR) and to an Autothermal Reformer (ATR) that operate in parallel. EP 1622827 describes a process for the production of synthesis gas starting from carbonaceous material, preferably comprising a gaseous hydrocarbon feedstock of Natural Gas, refinery gas and more generally gaseous streams containing compounds that have up to 4 carbon atoms, which envisages:

(a) a partial oxidation stage of the carbonaceous material performed in a reactor in which there is a burner in the top part (hence an ATR or POx reactor) thus obtaining a first mixture of hydrogen and carbon monoxide; (b) a catalytic Steam Reforming stage of the carbonaceous material in a tubular Convective Steam Reforming Reactor (CSR), 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 head of the 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 lead to the production in the CSR of a stream of synthesis gas at relatively low temperatures and with high residual methane content (between 5 - 30% mole/mole).

EP 1403216 describes a procedure for the production of synthesis gas by catalytic steam reforming in parallel in an AutoThermal Steam Reformer in series. The heat required by the SR steps is, also in this case, provided by the combination of effluents from the different SRs and ATRs. The final mixture of effluents obtained by adding the synthesis gas produced by the convectively heated SR and ATR processes has a H₂/CO ratio comprised between 1.8 and 2.3 v/v.

WO 2008017741 describes a process for the production of liquid hydrocarbons starting from biomasses, coal, lignite and crude oil residues that boil at a temperature of over 340°C, said process comprising at least:

one partial oxidation stage of the heavy feedstock in the presence of oxygen for producing a first synthesis gas, potentially purified, with a H₂/CO ratio less than 1 ; a Steam Reforming stage of the light feedstock having fewer than 10 atoms of carbon for producing a second synthesis gas, potentially purified, with a H₂/CO ratio greater than 3;

a Fischer-Tropsch (FT) stage for the conversion of the synthesis gas formed from the mixture of at least a part of the first and the second synthesis gas into proportions such that H₂/CO varies between 1.2 and 2.5;

a hydrocracking stage of at least one portion of the hydrocarbons produced with FT that boil over 150°C, wherein the light hydrocarbons produced in FT have fewer than 10 atoms of carbon.

Endothermic adiabatic "pre-reforming" reactors are often inserted upstream of the SR and ATR reactors. These reactors are described in various documents in literature including "T.S. Christensen, Appl. Catal. A: 138(1996)285" and "I. Dybkjaer, Fuel Process. Techn. 42(1995)85". The pre-reformers allow the C2+ hydrocarbons contained in the gaseous hydrocarbon streams to be converted at relatively low temperatures (about 550°C) into CO, H₂ and CH₄ reducing the possibility of parasite reactions taking place forming coal [7- 9] in the subsequent SR or ATR steps. In particular in endothermic pre-reforming reactors reactions [10 - 1 1] are performed that accompany the Water Gas Shift (WGS) reaction

[5].

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) ΔΗ^ο>0 [10]

CO+3H₂=CH₄+H₂0 AH°=-206kJ/mole [1 1 ]

CO+H₂0=C0₂+H₂ AH°=-41 kJ/mole [5]

Endothermic adiabatic pre-reforming reactors are typically fed with a mixture of gaseous reagents and steam pre-heated in an oven to about 550°C. In the endothermic adiabatic pre-reforming reactor a Ni based catalyst is used (in most cases) for completing reactions [10-1 1 ]. The pre-reformed gas mixture is then sent to the reforming reactor and has a lower thermodynamic affinity to reactions forming carbonaceous residues through reactions [7-9]. This allows the steam/carbon (Steam/C v/v) and/or Oxygen/Carbon (0₂/C) ratios fed to the SR or ATR reactors to be reduced, improving the energy efficiency (W.D. Verduijin Ammonia Plant Saf. 33(1993)165). The use of pre-reforming units also allows the flexibility of the SR and ATR technologies to be increased with respect to the composition of the feedstock; for example, it allows feedstock to be used that range from refinery gases to fuel oils. Finally, the use of endothermic adiabatic pre- reforming technology can increase the production capacity of plants without requiring significant changes to the characteristics of the reforming unit. As already highlighted, synthesis gas production technologies are used in a large number of industrial procedures to produce different products. It is therefore appropriate to be able to have a flexible synthesis gas production process both with respect to the composition of the reagent feedstock, with respect to the production capacity and with respect to the quality of synthesis gas produced. At the same time it is very important to use high energy efficiency procedures, with low carbon dioxide emissions and that require lower capital costs with respect to traditionally exploited technologies.

For that purpose, in the present patent application an integrated process is proposed, that combines the catalytic partial oxidation technology, particularly Short Contact Time (SCT- CPO), with the non-catalytic partial oxidation technology (POx).

The applicant has designed an integrated process for producing synthesis gas from carbonaceous compounds, liquid feedstock, gaseous feedstock, or combinations thereof which comprises the step of conducting in parallel one stage of short contact time catalytic partial oxidation (SCT-CPO) and a stage of non-catalytic partial oxidation (POx). The feedstock that can be used in said process are:

i) hydrocarbon gaseous streams, among these preferably natural gas and/or refinery gas, or gaseous compounds also deriving from bio-masses; or ii) carbonaceous compounds selected from coal, heavy residues from oil cycle processing, such as fuel oils, "vacuum" residues , and petroleum coke (petcoke) or iii) liquid compounds containing hydrocarbon compounds and/or compounds of various nature deriving from biomasses; and combinations thereof.

The integrated process according to the present patent application offers the following advantages:

I Increasing the compositional flexibility of the synthesis gas produced for optimal integration with the processes that use it, such as the following processes: a) production of NH₃/Urea, b) production of H₂ for refining and other various uses (refining metals, glass, electronics, food industries...), c) production of Methanol and its derivatives, d) Fischer Tropsch synthesis for GTL transformations, e) hydroformylation and fine chemistry processes.

II Improving the overall energy efficiency of production chains and using synthesis gas, hence reducing greenhouse gas emissions and potentially removing and reusing most of the C0₂ produced,

III Building plants with large production capacity,

IV Reducing the capital costs of supply chains "via synthesis gas",

V debottlenecking the production capacity of already existing plants.

Further objects and advantages of the present invention will appear more clearly from the following description and appended figures, provided by way of non-limitative example. Figures 1 - 6 describe various embodiments of the present invention.

DETAILED DESCRIPTION

The subject matter of the present patent application is an integrated process for producing synthesis gas from carbonaceous compounds, liquid feedstock, gaseous feedstock, or combinations thereof which comprises the step of conducting in parallel one stage of short contact time catalytic partial oxidation (SCT-CPO) and a stage of non- catalytic partial oxidation (POx).

The feedstock that can be used in said process are:

i) hydrocarbon gaseous streams, among these preferably natural gas and/or refinery gas, or gaseous compounds also deriving from bio-masses; or

ii) carbonaceous compounds selected from coal, heavy residues from oil processing cycles, such as fuel oils, "vacuum" residues and petroleum coke (petcoke) or iii) liquid compounds containing hydrocarbon compounds and/or compounds of various nature deriving from biomasses; and combinations thereof.

The feedstock of the integrated process may be pre-treated in one or more pre-reforming stages, which may preferably be exothermic adiabatic or endothermic adiabatic. In particular said pre-reforming stages are upstream of the SCT-CPO section.

Preferably hydrocarbon gaseous streams, among these preferably natural gas and/or refinery gas can be fed to an endothermic adiabatic pre-reformer or to an exothermic adiabatic pre-reformer placed upstream of an SCT-CPO reactor. Preferably gaseous compounds, wherein said gaseous compounds are different hydrocarbons from natural gas and/or refinery gas, or gaseous compounds also deriving from biomasses, can be fed either to an exothermic adiabatic pre-reformer or to an endothermic adiabatic pre- reformer placed upstream of an SCT-CPO.

Preferably liquid compounds containing hydrocarbon compounds and/or compounds of various nature deriving from bio-masses can be fed only to an exothermic adiabatic pre- reformer placed upstream of an SCT-CPO.

When combinations of liquid compounds and gaseous compounds are fed, they can be fed only to an exothermic adiabatic pre-reformer placed upstream of an SCT-CPO.

The pre-reforming stage generates a reformed stream that is subsequently fed to the SCT-CPO section.

The exothermic adiabatic pre-reforming stages exploit the same principles as an SCT- CPO process; an example is described in ITMI20120418.

The exothermic adiabatic pre-reforming stages also allow liquid hydrocarbon and gaseous feedstock to be pre-treated even with high olefin content and/or feedstock obtained from bio-masses that cannot be treated by endothermic adiabatic pre-reforming processes since they would cause:

i the deactivation of their catalytic systems,

ii the formation of carbonaceous residues which would make it impossible to handle industrial reactors.

A preferred embodiment according to the present invention envisages an integrated process comprising the following stages:

a) dividing a gaseous hydrocarbon stream into a first and a second stream, preferably containing natural gas and/or refinery gas, and/or a gas also deriving from bio- masses,

b) sending the first stream to a section of non-catalytic partial oxidation (POX) after mixing with a stream containing Oxygen and optionally steam, to form a first stream of synthesis gas,

c) sending the second stream to a short contact time catalytic partial oxidation section (SCT-CPO), after mixing with a stream containing oxygen; steam and optionally C0₂; and optionally with a third stream which may include:

i liquid compounds containing hydrocarbons and/or compounds of various nature deriving from bio-masses;

ii and combinations thereof.

The stream containing oxygen may be oxygen, air or enriched air. Said embodiment is advantageous since it allows an increase in the H₂/CO ratio produced by the POx reactor from Natural Gas and from other light gaseous

hydrocarbons, and the use of the synthesis gas produced in Fischer-Tropsch (FT) synthesis, in MeOH synthesis and in Ammonia synthesis, in the production of Hydrogen. In fact, POx technology that uses Natural Gas produces a synthesis gas with a low H₂/CO ratio (about 1 - 1 .5 v/v) rich in C0_2, which cannot be used advantageously directly for the production of H₂, for the synthesis of NH₃ and Urea, Methanol and its derivatives. For most of these applications the synthesis gas produced by POx technology must be subjected to purification treatment as well as a WGS [5] step for increasing its H₂/CO ratio and removing C0_2. These steps reduce the energy efficiency of the synthesis gas supply chain and increase the consumption of reagents per unit volume of final product.

Coupling with an SCT-CPO reactor allows the H₂/CO ratio to be adjusted to more suitable values for the subsequent uses and in particular to the F-T process and synthesis process of MeOH and its derivatives.

A further embodiment according to the present invention envisages an integrated process comprising the following stages:

sending a first stream containing carbonaceous compounds selected from coal, heavy residues of oil processing cycles such as vacuum residues, fuel oils and/or petcoke; to a section of non-catalytic partial oxidation (POx) after mixing with a stream containing oxygen,

sending a second stream comprising gaseous hydrocarbons, preferably natural gas; other gaseous compounds other than gaseous hydrocarbons also derived from biomasses, liquid compounds containing hydrocarbons and/or compounds of various nature deriving from biomasses; and combinations thereof; to a short contact time catalytic partial oxidation section (SCT-CPO) after it has been mixed with a stream containing oxygen; steam and optionally C0₂.

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

Said embodiment is advantageous in contexts in which there is low availability of Natural Gas, good availability of carbonaceous materials such as coal, heavy residues from crude oil processing cycles such as, for example, vacuum residues, fuel oils and petcoke, for obtaining synthesis gas to be used in the synthesis of F-T, MeOH, Ammonia and hydrogen. POx reactors fed with these carbonaceous compounds produce a synthesis gas very rich in CO and C0₂ (typically if using petcoke with a H₂/CO ratio of 0.6 v/v) which must be initially purified from the pollution of the catalysts of processes that use the synthesis gas (sulfured and nitrogenous compounds but also of other kinds according to the hydrocarbon feedstock used) and generally from some carbonaceous residues. The synthesis gas with low H₂/CO ratio must then be subjected to WGS [5] treatments and treatments for removing C0₂ before being sent to the processes that use it. Should be available in the same context also a gaseous hydrocarbon stream such as, for example, natural gas or refinery gas, this mixture can be sent to an SCT-CPO reactor along with a stream containing oxygen, and steam so as to obtain particularly high steam/carbon (S/C) ratios (S/C = 1 - 3 v/v) obtaining a synthesis gas with a high H₂/CO ratio which, added to the synthesis gas stream coming from the POx, can reduce the dimensions of the WSG reactors and the associated steam consumptions.

Both preferred embodiments of the process therefore exploit the possibilities offered by SCT-CPO technology to use, while maintaining the high energy efficiency typical of catalytic transformations, different types of feedstock for producing synthesis gas which, integrated with the production of synthesis gas of POx reactors, allows the H₂/CO ratio to be adjusted to more suitable values for the processes that use it, by improving the overall energy efficiency of supply chains via synthesis gas. Although POx technology is able to treat a very wide feedstock range, its energy consumptions are, in fact, higher than those of CPO technology since its non-catalytic reactions are less selective and take place at 300°C-600°C higher temperatures than those of catalytic technologies and in particular than SCT-CPO technology, which does not use either a burner or a combustion chamber. After the POx and SCT-CPO stages, the first and second stream of synthesis gas produced can be sent separately to two heat exchange devices for cooling to a temperature below 400°C generating co-production of steam; or can be mixed and the resulting mixture is sent to a single heat exchange device for cooling to temperature values below 400°C for generating steam.

The steam generated can be used partly as a reagent in the POx section and partly fed to the SCT-CPO section.

If the gaseous hydrocarbon stream contains sulfured compounds, it can be subjected to a hydro-desulfurization treatment before being sent to the pre-reforming section, or before being sent to the POx and SCT-CPO sections. If necessary, the impurities that could pollute the processes downstream of the reactors producing synthesis gas, can also be removed in a sulfide or impurity removal unit downstream of the POx and SCT-CPO reactors.

Preferably the heat exchange device that cools the synthesis gas in the process according to the present invention is a syngas cooler which comprises:

• at least one vertically oriented tank containing a cooling fluid bath and having a collecting space of the vapor phase generated above said bath of cooling fluid,

• at least one vertical tubular element inserted internally of said tank, open at the ends and coaxial to said tank,

• at least one spiral duct which rotates around the axis of the tank, inserted in said coaxial tubular element, • at least one outlet for the vapor phase generated on the head of said tank, said exchanger having at the lower part of the vertical tank at least one transfer line for feeding the hot gases to said tank, said transfer line being open at the two ends one of which is connected with the vertical tank and the other free and external to said tank, said transfer line being tubular shaped and projecting laterally outside said exchanger, said transfer line containing at least one central internal duct having an external jacket in which a coolant fluid circulates, said central internal duct being fluidly connected to the spiral duct and extending vertically along the tubular element inserted in the vertical tank. Preferably the heat exchange device that cools the synthesis gas in the process according to the present invention is a syngas cooler which comprises:

• a single apparatus having an area immersed in a fluid bath and a free space in the head where a vapor phase accumulates,

• at least a cavity open at both ends placed inside of said apparatus and completely immersed in the fluid bath,

• one or more heat exchange surfaces,

• at least an inlet nozzle for one or more streams of cold material coming from a cold external source and at least one inlet nozzle for one or more flows of a hot material from a hot external source,

• at least one outlet nozzle for at least a flow of cooled material and at least one

outlet for at least one flow of material heated by said heat exchange surfaces, said device containing in a single apparatus all the heat exchange surfaces and said surfaces being completely immersed in the fluid bath and being fluidly connected to the hot and cold sources external to said system through flows of material.

If it is decided to convert all or part of the carbon monoxide contained in the synthesis gas and to increase the hydrogen content, after cooling, the synthesis gas streams can be sent to separate Water Gas Shift (WGS) sections in which reaction [2] of Table 1 can take place; or they can be sent to a single WGS section, hence forming in both cases a gas stream mainly containing H₂, CO and C0₂from which through a

separation/purification process an H₂ stream with a high degree of purity can be obtained. The stream of gas containing H₂, CO and C0₂ can be cooled generating steam which is used partly to feed the sections of POx and SCT-CPO and partly can be exported for other uses.

The synthesis gas produced in both sections of POx and SCT-CPO can be used for the synthesis of liquid hydrocarbons via Fischer Tropsch.

The synthesis gas produced both by POx and by SCT-CPO can be used in a process for the synthesis of methanol.

The integrated production of synthesis gas through POx and SCT-CPO can also be used in many other via-syngas processes such as, for example, the reduction of ferrous minerals, hydroformylations and synthesis of acetic acid. In some cases the synthesis gas produced by POx and SCT-CPO can also be sent to one or more water gas shift (WGS) reactors and enriched in Hydrogen which can then be separated and used in various refining or hydro-treatment processes.

Integration between POX and SCT-CPO sections allows operational and economic advantages in the production of synthesis gas and in the procedures that use it. In particular said configuration allows both increasing the production limits in existing POx plants, and using reagents with different compositions and producing syngas mixtures suitable for the different production supply chains. The adiabatic oxidative "pre-reforming" stages allow reducing the energy consumptions in the subsequent reaction stages and further increase the flexibility of the synthesis gas production processes. Furthermore, exothermic pre-reformers also allow using complex gaseous hydrocarbon feedstock rich in olefin content present in some refinery gases, and in general those gaseous, liquid feedstock and oxygenated compounds that an endothermic pre-reformer would otherwise not be able to use, since they would cause the deactivation of catalytic systems and the formation of carbonaceous deposits.

More in detail Figures 1 - 6 describe some preferred embodiments according to the present invention.

In Figure 1 a stream of natural gas (2) is desulfurized in a hydro-desulfurization treatment unit (5), then it is split into two streams. Each stream is mixed with steam (1 ,4) and a stream containing oxygen (3) before being sent to a POx section or to an SCT-CPO section each producing a synthesis gas (12, 13) which is cooled in two heat exchangers (8,9). Cooling allows steam to be generated which is sent for feeding (1 ,4) or exported for other uses (10,1 1 ). After cooling the two streams of synthesis gas are reunited (14) producing a synthesis gas suitable for various uses.

Figure 2 reproduces the diagram of Figure 1 in addition to an exothermic adiabatic pre- reformer (15). Part of the natural gas (2) is mixed with a share of stream containing oxygen (3) and a stream containing liquid hydrocarbons and compounds deriving from bio-masses (4). The mixture thus formed is fed to the exothermic adiabatic pre-reformer placed upstream of an SCT-CPO.

In Figure 3 a stream of petcoke or heavy hydrocarbons is mixed with a stream containing oxygen (3) and potentially with steam (1 ), then it is fed to a POx reactor thus producing a first synthesis gas.

A hydro-desulfurized (5) gaseous hydrocarbon stream (2) is mixed with other liquid feedstock chosen from hydrocarbons and/or compounds deriving from bio-masses (4), with a stream containing oxygen (3) and with steam (1 1 ) forming a mixture that is fed to an exothermic adiabatic pre-reforming reactor (15). The pre-reformed gas leaving (15) is then fed to SCT-CPO in the presence of a stream containing oxygen (3) forming a second synthesis gas. The first and the second synthesis gases are cooled in two separate syngas coolers (8,9) generating steam which is both used by the synthesis gas production processes (1 , 1 1 ) and exported (10, 1 1 ). The stream of synthesis gas produced by the POx reactor after cooling, is subjected to a treatment (16) for removing sulfur compounds and washing carbonaceous particles and other impurities contained in heavy hydrocarbon feedstock or in coke, before being mixed with the synthesis gas produced by the SCT-CPO process to form the final product (14).

In Figure 4 the synthesis gas produced with the diagram shown in Figure 2 is used in a Fischer-Tropsch process (20). However, in this diagram it is envisaged that part of the "recycling gas" (17) of the Fischer-Tropsch process is purged and re-fed to the POx and/or SCT-CPO reactors (18).

In Figure 5 the synthesis gas streams are produced with the same diagram shown in Figure 3. The synthesis gas produced in POx after cooling (8) is subjected to treatment for removing (16) the sulfured compounds, carbonaceous residues and all the impurities contained in the heavy hydrocarbon feedstock or in the coke, and is subsequently sent to a Water Gas Shift reactor (17) along with the steam (28). The synthesis gas "shifted" and that coming from the SCT-CPO reactor are reunited (14) producing a stream that is compressed (22) and sent to a Methanol synthesis reactor (24), whose effluents are distilled (25) to produce Methanol (26).

Figure 6 reproduces the diagram of Figure 5 but the synthesis gas leaving from SCT- CPO is made to react with steam (27) in a water gas shift (29). The shifted gas is reunited (30) and sent to a C0₂ removal stage (31 ) producing two streams of pure hydrogen (33) and one very rich in C0₂ (32).

Claims

An integrated process for producing synthesis gas from carbonaceous compounds, liquid feedstock, gaseous feedstock, or combinations thereof which comprises the step of conducting in parallel one stage of short contact time catalytic partial oxidation (SCT-CPO) and a stage of non-catalytic partial oxidation (POx).

The process according to claim 1 where the feedstock is selected from:

i hydrocarbon gaseous streams, among these preferably natural gas and/or refinery gas, or gaseous compounds also deriving from bio-masses; or ii carbonaceous compounds selected from coal, heavy residues from oil

processing cycles, such as fuel oils, "vacuum" residues, and petroleum coke (petcoke) or

iii liquid compounds containing hydrocarbon compounds and/or compounds of various nature deriving from biomass;

iv and combinations thereof.

The process according to claims 1 or 2 in which the feedstock of the integrated process is pre-treated in one or more pre-reforming stages.

The process according to claim 3 wherein the pre-reforming step is exothermic adiabatic or endothermic adiabatic.

The process according to claim 3, wherein said pre-reforming stages are placed upstream of the section of the short contact time catalytic partial oxidation section. The process according to claim 3 wherein the gaseous hydrocarbon streams, preferably natural gas and/or refinery gas, are fed to an endothermic adiabatic pre- reformer or an exothermic adiabatic pre-reformer placed upstream of a short contact time catalytic partial oxidation reaction section.

The process according to claim 3 wherein the gaseous compounds selected from hydrocarbons other than natural gas and/or refinery gas, or among gaseous compounds also deriving from bio-masses, are 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.

8. The process according to claim 3 wherein the liquid compounds containing

hydrocarbon compounds and/or compounds of various nature deriving from bio- masses are fed only to an exothermic adiabatic pre-reformer placed upstream of short contact time catalytic partial oxidation section.

9. The process according to claim 3 wherein when combinations of liquid and gaseous compounds are fed, these are fed only to an exothermic adiabatic pre-reformer placed upstream of a short contact time catalytic partial oxidation section.

10. The integrated process according to claim 1 which comprises the following stages: a. dividing a gaseous hydrocarbon stream into a first and a second stream, preferably containing natural gas and/or refinery gas, and/or a gas also deriving from bio-masses,

b. sending the first stream to a section of non-catalytic partial oxidation (POX) after mixing with a stream containing oxygen and optionally steam, to form a first stream of synthesis gas,

c. sending the second stream to a short contact time catalytic partial oxidation section (SCT-CPO), after mixing with a stream containing oxygen; steam and optionally C0₂; and optionally with a third stream which may include:

i. liquid compounds containing hydrocarbons and/or compounds of

various nature deriving from bio-masses;

ii. and combinations thereof.

1 1 . The integrated process according to claim 1 which comprises the following stages: sending a first stream containing carbonaceous compounds selected from coal, heavy residues of the oil processing cycles such as vacuum residues, fuel oils and/or petcoke; to a section of non-catalytic partial oxidation after mixing with a stream containing oxygen,

sending a second stream comprising gaseous hydrocarbons, preferably natural gas; other gaseous compounds other than gaseous hydrocarbons also derived from biomass, liquid compounds containing hydrocarbons and/or compounds of various nature deriving from biomass; and combinations thereof; to a short contact time catalytic partial oxidation section after it has been mixed with a stream containing oxygen; steam and optionally C0₂.

12. The integrated process for the production of synthesis gas according to any one of claims 1 to 1 1 wherein the first and the second stream of synthesis gas are each sent separately to a single heat exchange device for cooling to a temperature less than 400 °C, generating a co-production of steam, or are mixed and the resulting mixture is sent to a single heat exchange device for cooling to temperatures below 400 °C and for steam generation.

13. The integrated process according to claim 12 wherein the generated steam is used partially as a reactant in the non-catalytic partial oxidation section and is partially fed to the short contact time catalytic partial oxidation section.

14. The process according to any one of claims 1 to 13 wherein the gaseous

hydrocarbon feedstock contains sulfur compounds and is subjected to a hydro- desulfurization treatment before being sent to the pre-reforming sections or the non- catalytic partial oxidation sections and short contact time catalytic partial oxidation sections.

15. The integrated process according to any one of claims 12 to 14 wherein the heat exchange device that cools the synthesis gas comprises:

i at least one vertically oriented tank containing a cooling fluid bath and having a collecting space of the vapor phase generated above said bath of cooling fluid,

ii at least one vertical tubular element inserted internally of said tank, open at the ends and coaxial to said tank,

iii at least one spiral duct which rotates around the axis of the tank, inserted in said coaxial tubular element,

iv at least one outlet for the vapor phase generated on the head of said tank, said heat exchanger having in the lower part of the vertical tank at least one transfer line for supplying hot gases to said tank,

said transfer line being open at the two ends of which is connected with the vertical tank and the other free and external to said tank,

said transfer line being tubular in shape and protruding laterally out from said exchanger,

said transfer line containing at least one internal central duct having an external jacket in which circulates a cooling fluid,

said internal central duct being fluidly connected to the internal spiral duct and developing vertically along the tubular element inserted into the vertical tank.

16. The integrated process according to any one of claims 12 to 14 wherein the heat exchange device that cools the synthesis gas comprises:

a single apparatus having an area immersed in a fluid bath and a free space in the head where a vapor phase accumulates,

at least a cavity open at both ends placed inside of said apparatus and completely immersed in the fluid bath, one or more heat exchange surfaces,

at least an inlet nozzle for one or more streams of cold material coming from a cold external source and at least one inlet nozzle for one or more flows of a hot material from a hot external source,

at least one outlet nozzle for at least a flow of cooled material and at least one outlet for at least one flow of material heated by said heat exchange surfaces, said device containing in a single apparatus all the heat exchange surfaces and said surfaces being completely immersed in the fluid bath and being fluidly connected to the hot and cold sources external to said system through flows of material.

17. The integrated process according to any one of claims 1 to 16 which further

comprises a stage in which the synthesis gas produced by both non-catalytic partial oxidation is by catalytic partial oxidation at low contact time is used in a process for the methanol synthesis.

18. The integrated process according to any one of claims 1 to 17 wherein the

synthesis gas produced by both non-catalytic partial oxidation and by catalytic partial oxidation at low contact time is used in a process for the ammonia and urea synthesis.

19. The integrated process according to any one of claims 1 to 18 in which the

synthesis gas produced by both non-catalytic partial oxidation and by short contact time catalytic partial oxidation is used in a process for the synthesis of the Fischer- Tropsch process that includes a recycling of products of Fischer-Tropsch upstream of the short contact time catalytic partial oxidation stage and/or the non-catalytic partial oxidation stage.

20. The integrated process according to any one of claims 1 -19 in which after cooling the streams of synthesis gas are sent separately to the Water Gas Shift separate sections, or the mixture of cooled synthesis gas is sent to a single section of Water Gas Shift, thus forming in both cases a gas stream containing mainly H₂, CO and C0₂from which a H2 stream

The integrated process according to claim 1 -20 in which the gas stream containing H₂, CO and C0₂ is cooled by generating steam that is used in part to feed the non- catalytic partial oxidation sections and catalytic partial oxidation at short time contact.