Utilizing the oxygen from water electrolysis in a partial oxidation process (POX)

Abstract

A process for producing a synthesis gas mixture comprising hydrogen and carbon monoxide and optionally carbon dioxide by partial oxidation of hydrocarbons or a mixture comprising hydrocarbons comprising: Reacting the hydrocarbons or the mixture comprising hydrocarbons with an oxygen-comprising reactant gas, wherein the oxygen in said oxygen-comprising reactant gas comprises at least 1 ppmv of H2 based on the total volume of the oxygen-comprising reactant gas; a synthesis gas mixture obtainable or obtained by the inventive process; a synthesis gas mixture comprising hydrogen and carbon monoxide and optionally carbon dioxide, wherein the synthesis gas has a δ18O value of < 22 ‰, referred to the international standard VSMOW; and use of an oxygen-comprising reactant gas comprising at least 1 ppmv of H2 based on the total volume of the oxygen-comprising reactant gas for the preparation of a synthesis gas mixture comprising hydrogen and carbon monoxide and optionally carbon dioxide by partial oxidation of hydrocarbons or a mixture comprising hydrocarbons. The present invention further relates to a partial oxidation reactor (POX reactor) comprising a connection for supplying an oxygen-comprising reactant gas comprising at least 1 ppmv of H2 based on the total volume of the oxygen-comprising reactant gas; and a system comprising a partial oxidation reactor (POX reactor) and a water electrolyzer connected by a gas pipe.

Description

Utilizing the oxygen from water electrolysis in a partial oxidation process (POx)The present invention relates to a process for producing a synthesis gas mixture comprising hydrogen and carbon monoxide and optionally carbon dioxide by partial oxidation of hydrocarbons or a mixture comprising hydrocarbons comprising: Reacting the hydrocarbons or the mixture comprising hydrocarbons with an oxygen-comprising reactant gas, wherein said oxygen-comprising reactant gas comprises at least 1 ppmv of H2 based on the total volume of the oxygen-comprising reactant gas, wherein the oxygen in the oxygen-comprising reactant gas is obtained at least in part by a water electrolysis without any further purification steps;; and use of an oxygen-comprising reactant gas comprising at least 1 ppmv of H2 based on the total volume of the oxygen-comprising reactant gas for the preparation of a synthesis gas mixture comprising hydrogen and carbon monoxide and optionally carbon dioxide by partial oxidation of hydrocarbons or a mixture comprising hydrocarbons. The present invention further relates to a partial oxidation reactor (POX reactor) comprising a connection for supplying an oxygen-comprising reactant gas comprising at least 1 ppmv of H2 based on the total volume of the oxygen-comprising reactant gas, being a direct connection without any purification unit between the oxidation reactor and a water electrolyzer; and a system comprising a partial oxidation reactor (POX reactor) and a water electrolyzer connected by a gas pipe, being a direct connection without any purification unit between the oxidation reactor and the water electrolyzer.Synthesis gas, also known as syngas, generally is a mixture comprising carbon monoxide (CO) and hydrogen (H2). Syngas with various H2 / CO ratios is used to produce a wide range of chemicals, such as methanol, ammonia, synthetic hydrocarbons and other high value-added products. Syngas is not only a semi-product of the synthesis of more complex organic compounds, but also the main source of hydrogen production.Syngas can be produced from many sources, including natural gas, coal, and biomass. The most common methods for producing syngas and hydrogen from natural gas / methane are steam reforming, autothermal reforming and partial oxidation (oxidative conversion).For the supply of chemical processes with syngas the partial oxidation process will gain relevance, as it isI. A low carbon emitting technology ii. It allows the utilization of feedstock of the recycling economy (e.g. pyrolysis oils from plastic waste or used tires).By partial oxidation of hydrocarbons, syngas comprising carbon monoxide (CO) and hydrogen (H2) can obtained. The process is generally controlled by the sub-stoichiometric oxygen supply. The resulting syngas generally has a molar H2 / CO ratio of generally 0.6 - 4 to 1 (depending on the feedstock and conditions employed).The general equation for partial oxidation is as follows:The known processes for the production of syngas through partial oxidation generally use oxygen gas as oxidant in the partial oxidation process.The oxygen gas employed in the known partial oxidation processes for preparing syngas is generally obtained by separation from the atmosphere. Commercial large-scale air separation plants (ASU, Air Separation Unit) are based on cryogenic distillation technology, capable of supplying oxygen at high purity and pressure. The conventional oxygen obtained by separation from the atmosphere generally comprises a certain amount of air (i.e. mainly N2, Argon, CO2) e.g. Oxygen 2.5 comprises 99.5 Vol% O2 and < 5000 ppmv air. Oxygen 2.5 is a typical "technical grade” oxygen gas used for industrial partial oxidation processes. However, Oxygen (O2) production, especially the production of high purity oxygen, is a major part of the energy consumption and capital cost of for industrial processes such as partial oxidation requiring large quantities of oxygen as a raw material. Typical electric power consumption for conventional ASU plants is approx. 245 kWh / t of oxygen 99% purity (Linde Engineering Group, see Hesari et al, General design consideration of cryogenic air separation unit for esfahan steel company, J. Gas Technology, Vol. 5, Issue 1 (2020), pp. 32-42) and this energy consumption is increasing steeply with even higher oxygen purity requirements such as Oxygen 2.5 and above (doi: 10.1016 / j.egypro.2014.11 .054, Fig. 4)A relevant part of the total product carbon footprint of syngas prepared by the partial oxidation process and downstream products is therefore based on the raw material oxygen employed.The reduction of greenhouse gas emissions and therefore the reduction of the product carbon footprint is one of the main issues of our time.A way of reducing the product carbon footprint of syngas and downstream products is the provision of a process with a total raw material and energy consumption which is as low as possible, the utilization of raw materials and energy with a low carbon emission backpack as well as the avoidance of waste generation.US 2007 / 131909 A1 relates to a process for the production of a synthesis gas (SG) starting from a carbon-containing material is relatively low in hydrogen; water; and electrical energy, wherein: Electrolysis of the water is carried out to produce oxygen and, hydrogen; a flow (CF) that comprises at least the majority of carbon contained in the carbon- containing material is subjected to a partial oxidation (POX) with essentially pure oxygen produced by said electrolysis; at least a portion of the hydrogen that is produced by electrolysis is added to the flow (CF) upstream and / or downstream from the partial oxidation POX. It is mentioned that the electrolysis can be carried out under a relatively high pressure. It is emphasized in claim 1 and

[0020] in US 2007 / 131909 A1 that the carbon-containing material CF is subject to a partial oxidation POX with oxygen that is essentially pure and is produced by electrolysis.US 10 889 496 B2 relates to a combination of electrolysis of water, autothermal reforming (ATR) and heat exchange reforming of a hydrocarbon feed stock in the preparation of a hydrogen and carbon oxides containing synthesis gas. In an ATR reactor, partial oxidation or combustion of a hydrocarbon feed by substoichiometric amounts of oxygen is followed by steam reforming of the partially combusted hydrocarbon feed stream in a fixed bed of steam reforming catalyst. ATR is a reforming technology different from partial oxidation, POX.US 2024 / 150169 A1 relates in one embodiment to a liquid fuel manufacturing system is disclosed. The system includes an electrolyzer configured to produce hydrogen and oxygen. The system includes a gasifier configured to produce carbon monoxide, hydrogen, and water from an organic feedstock and oxygen from the electrolyzer. However, US 2024 / 150169 A1 is silent as to the purity of the oxygen employed as well as to any electrolysis conditions.US 2014 / 288195 A1 relates to a process for the thermochemical conversion of a carbon-based feedstock to synthesis gas containing predominantly hydrogen (H2) and carbon monoxide (CO), comprising the following steps:(a) oxycombustion ofthe carbon-based feedstock to create a cogeneration of electricity and of heat;(b) high-temperature electrolysis (HTE) of water using at least the heat produced according to step (a);(c) reverse water gas shift (RWGS) reaction starting from the carbon dioxide (CO2 ) produced according to step ( a) and the hydrogen (H2 ) produced according to step (b). The oxygen produced in the HTE can be used as oxidizing agent in step (a). However, it is mentioned in

[0026] that pure 02 can be used as oxidizing agent in the oxycombustion.US 2016 / 136608 A1 relates to a plant for the efficient utilization of excess electric energy, comprising: a) a first apparatus for the electrochemical or electrothermal production of hydrogen, which produces a first hydrogen stream, e.g. an apparatus for the electrolysis of an aqueous solution to form hydrogen and oxygen; b) a second apparatus for producing hydrogen from a hydrocarbon by steam reforming, partial oxidation or dehydrogenation, which produces a second hydrogen stream; c) a hydrogen conduit or a hydrogen consumer to which both the first hydrogen stream and the second hydrogen stream are fed; and d) a control device matching the production of hydrogen in the first apparatus and in the second apparatus in such a way that the total amount of first hydrogen stream and second hydrogen stream corresponds to a predetermined value; and a process carried out in said plant. US 2016 / 136608 A1 is silent as to the use of the oxygen obtained in the apparatus for electrolysis.US 2022 / 113271 A1 relates to a gas concentration detection method comprising: generating hydrogen and oxygen by water electrolysis; and detecting, by a catalytic combustion type gas sensor, an oxygen concentration in a hydrogen path for recovering the hydrogen or a hydrogen concentration in an oxygen path for recovering the oxygen, the catalytic combustion type gas sensor being arranged in at least one of the hydrogen path and the oxygen path.US 2023 / 212759 A1 relates to a system and method of purifying or upgrading a crude oxygen stream and crude hydrogen stream produced from an electrolysis unit. According to US 2023 / 212759 A1

[0004] , the crude oxygen stream (leaving a typical water electrolysis) will go through conventional catalytic and drying processes which will remove the water as well as reduce the hydrogen concentration to less than about 1 ppm. US 2023 / 212759 A1 provides a lower cost, stand-alone, purification system and method to co-produce ultra-high purity oxygen product and an ultra-high purity hydrogen product (for electronics manufacturing) from a crude oxygen and crude hydrogen streams produced by an electrolysis system that does not require integration into the coldbox of a full air separation unit and does not require oxygen compression.It was accordingly an object of the invention to provide an environmentally friendly process for preparing syngas by partial oxidation of hydrocarbons with a low product carbon footprint of the syngas and downstream products obtained.The object is achieved by a process for producing a synthesis gas (syngas) mixture comprising hydrogen and carbon monoxide and optionally carbon dioxide by partial oxidation of hydrocarbons or a mixture comprising hydrocarbons comprising:Reacting the hydrocarbons or the mixture comprising hydrocarbons with an oxygen-comprising reactant gas, wherein said oxygen-comprising reactant gas comprises at least 1 ppmv of H2 based on the total volume of the oxy- gen-comprising reactant gas, wherein the oxygen in the oxygen-comprising reactant gas is obtained at least in part by a water electrolysis without any further purification steps.Preferably, the water electrolysis, is carried out using energy generated at least in part from non-fossil resources.In the meaning of the present invention oxygen means O2 and hydrogen means H2.Hydrogen is considered a promising candidate that is increasingly intended to replace fossil fuels. To cut down greenhouse gas emissions, it is essential that future hydrogen production is based on renewable energy sources. One such possibility is the electrolysis of water, provided it is operated with electricity from renewable energy sources. Oxygen is produced as a by-product of water electrolysis, which is usually released into the environment without further use. The electrolysis of 9 tons of water gives 1 ton of hydrogen and 8 tons of oxygen gas, but usually only the hydrogen is used as a value product.The use of the by-product oxygen from electrolysis in the process for producing synthesis gas by partial oxidation of hydrocarbons improves the environmental friendliness of the process for preparing synthesis gas by partial oxidation of hydrocarbons, since the energy demanding provision of the oxygen obtained by conventional air separation from the atmosphere generally used in said process is replaced by the provision of surplus oxygen from the electrolysis of water.Further, the typical demand of a site with various synthesis gas consumers comes usually at a higher demand for hydrogen compared to the demand for carbon monoxide. Therefore, the combination of a partial oxidation (POx) plant with a water-splitting, especially a water-electrolysis seems reasonable.The by-product oxygen from water electrolysis comprises not negligible quantities of hydrogen and generally also water (impurities). Residual hydrogen is always found in the oxygen gas due to cross-over effects of the very mobile H2 molecules and the gaseous electrolysis products show close to full saturation with water / humidity (physical saturation based on electrolysis temperature / pressure conditions). E.g. up to 4 Vol%, normally up to 2 Vol% of hydrogen, limited by safety shut-off limits (explosive range begins at about 4 Vol% H2 in O2 at 1 atm) and water in the same order of magnitude. The exact content of hydrogen and water humidity in the oxygen gas produced by water electrolysis largely depends on temperature and pressure operating conditions.It is known that the hydrogen crossover (i.e. the amount of hydrogen in electrolysis-oxygen) electrolysis methods and conditions, e.g. temperature, cathode hydrogen partial pressure, and current density.For most uses the impurities exceed the acceptable amount. However, it has been found by the inventors of the present invention that this does not apply for the partial oxidation (POx) process. Therefore, while the water splitting, especially water electrolysis adds the required amount of hydrogen to the overall demand of a site, the by-product oxygen can be utilized in the POx process without any further purification steps.The presence of significant amounts of hydrogen in the oxygen-comprising reactant gas is not only not detrimental to the partial oxidation of hydrocarbons, it even offers advantages: Hydrogen in the oxygen-comprising reactant gas has a positive effect- on the soot generation (reduction, leading to lower waste generation and longer running-time due to foulingreduction downstream of the flame reactor) and- on the CO / CO2-ratio (increase, leading to higher output of synthesis gas value product and less CO2 waste generation).So the combination of these two technologies allows to utilize the by-product oxygen produced by water splitting, especially water electrolysis without violating any purity specifications.The inventors therefore found a new oxygen source for the environmentally friendly preparation of synthesis gas by partial oxidation of hydrocarbons.The process of the present invention is particularly environmentally friendly since the oxygen-comprising reactant gas (oxidizing agent) is obtained at least in part by water electrolysis. Preferably, the oxygen-comprising reactant gas is completely obtained from water splitting by electrolysis.The inventors of the present invention found that the oxygen obtained by water electrolysis can utilized in the partial oxidation without any further purification steps. The present invention therefore preferably relates to the process according to the present invention, wherein oxygen comprising reaction gas comprises, preferably consist of the oxygen obtained by water electrolysis without any further purification steps. I.e., the oxygen obtained by water electrolysis is directly used in the inventive partial oxidation process without any further purification steps.The water electrolysis, preferably uses energy generated at least in part from non-fossil resources. More preferably, the water electrolysis uses energy generated completely from non-fossil resources.The synthesis gas mixture obtainable or obtained by the inventive process is preferably a synthesis gas mixture comprising hydrogen and carbon monoxide and optionally carbon dioxide, wherein the synthesis gas has a 5180 value of < 22 %o, preferably, < 20 %o, more preferably < 18 %o, referred to the international standard VSMOW.The present invention further relates to a use of an oxygen-comprising reactant gas obtained at least in part by water electrolysis, preferably using energy generated at least in part from non-fossil resources for the preparation of a synthesis gas mixture comprising hydrogen and carbon monoxide and optionally carbon dioxide by partial oxidation of hydrocarbons or a mixture comprising hydrocarbons, and to the use of an oxygen-comprising reactant gas comprising at least 1 ppmv of H2 based on the total volume of the oxygen-comprising reactant gas for the preparation of a synthesis gas mixture comprising hydrogen and carbon monoxide and optionally carbon dioxide by partial oxidation of hydrocarbons or a mixture comprising hydrocarbons.The present invention further relates to the use of the synthesis gas obtained according to the process of the present invention for the preparation of methanol, fuel applications, formaldehyde, acetic acid, olefins, sodium methylate, methylation products, dimethylterephthalate, methylamine, methyl mercaptane, polyoxymethylene, butynediol, meth- ylendiphenyldiisocyanate, neopentylglycol, phenol formaldehyde resins, urea-condensation resins, melamine resins, acetone resins, chloroacetic acid, acetic acid ester, methylisipropylketone, acetic acid anhydride, dimethylsulfide, methanesulfonic acid and downstream products.In a further embodiment, the present invention further relates to the use of the synthesis gas obtained according to the process of the present invention for the preparation of formaldehyde, acetic acid, olefins, sodium methylate, methylation products, dimethylterephthalate, methylamine, methyl mercaptane, polyoxymethylene, butynediol, meth- ylendiphenyldiisocyanate, neopentylglycol, phenol formaldehyde resins, urea-condensation resins, melamine resins, acetone resins, chloroacetic acid, acetic acid ester, methylisipropylketone, acetic acid anhydride, dimethylsulfide, methanesulfonic acid and downstream products.The present invention further relates to a partial oxidation reactor (POX reactor) comprising a connection for supplying an oxygen-comprising reactant gas obtained at least in part by water electrolysis; and a system comprising a partial oxidation reactor (POX reactor) and a water electrolyzer connected by a gas pipe. Since the oxygen obtained bywater electrolysis is preferably utilized without any further purification steps, the connection between the partial oxidation reactor and the water electrolyzer is a direct connection without any purification unit between the oxidation reactor and the water electrolyzer.The inventive process comprises:Reacting hydrocarbons or a mixture comprising hydrocarbons with an oxygen-comprising reactant gas, wherein said oxygen-comprising reactant gas comprises at least 1 ppmv of H2 based on the total volume of the oxy- gen-comprising reactant gas, wherein the oxygen in the oxygen-comprising reactant gas is obtained at least in part by a water electrolysis without any further purification steps.Preferably, the water electrolysis, is carried out using energy generated at least in part from non-fossil resources.Suitable hydrocarbons or mixtures comprising hydrocarbons can be in a gaseous, liquid or solid state, or in a combination as desired, for example, a solid-liquid composition in a fluidized state.Suitable hydrocarbons or mixtures comprising hydrocarbons are generally any known hydrocarbons or mixtures comprising hydrocarbons, e.g. fossil hydrocarbon feedstocks, like petroleum based feedstocks including petroleum coke, coal residual oils and byproducts from heavy crude oils (the coal or coke can be in a finely divided state), hydrocarbons or hydrocarbon mixtures having from 1 to 12 carbon atoms, preferably natural gas, methane, LPG, naphtha and mixtures thereof), hydrocarbon feedstocks of the recycling economy (like plastic waste), and mixtures thereof.In the context of the present invention, the term "polymeric waste” (or "plastic waste”) preferably refers to any plastic material discarded after use, i.e., the plastic material has reached the end of its useful life and is considered postconsumer waste. The plastic waste can be pure polymeric plastic waste, mixed plastic waste or film waste, including soiling, adhesive materials, fillers, residues etc. The plastic waste may have an oxygen content, a nitrogen content, sulfur content, halogen content and optionally also a heavy metal content. The plastic waste can originate from any plastic material containing source. In another aspect, the term "plastic waste” also includes production waste e.g., from polymer processing in factories.Accordingly, the term "polymeric waste” includes industrial and domestic plastic waste and including used tires and agricultural and horticultural plastic material.Typically, polymeric waste is a mixture of different plastic materials, including hydrocarbon plastics, e.g., polyolefins such as polyethylene (HDPE, LDPE) and polypropylene, polystyrene, and copolymers thereof, etc., and polymers composed of carbon, hydrogen, and other elements such as chlorine, fluorine, oxygen, nitrogen, sulfur, silicone, etc., for example chlorinated plastics, such as polyvinylchloride (PVC), polyvinylidene chloride (PVDC), etc., nitrogen-con- taining plastics, such as polyamides (PA), polyurethanes (PU), acrylonitrile butadiene styrene (ABS), etc., oxygen-containing plastics such as polyesters, e.g., polyethylene terephthalate (PET), polycarbonate (PC), etc., silicones and / or sulfur bridges crosslinked rubbers.Typically, the plastic material comprises additives, such as processing aids, plasticizers, flame retardants, pigments, light stabilizers, lubricants, impact modifiers, antistatic agents, antioxidants, etc. These additives may comprise elements other than carbon and hydrogen. For example, bromine is mainly found in connection to flame retardants. Heavy metal compounds may be used as lightfast pigments and / or stabilizers in plastics. Cadmium, zinc, and lead may be present in heat stabilizers and slip agents used in plastics manufacturing. The plastic waste can also contain residues. Residues in the sense of the invention are contaminants adhering to the plastic waste. The additives and residues are usually present in an amount of less than 50 wt%, preferably less than 30 wt%, more preferably less than 20 wt%, even more preferably less than 10 wt%, based on the total weight of the dry weight plastic.Examples of rubber waste (which is also considered "polymeric waste” in the sense of the present invention) include tires, generally end-of-life tires (ELT), rubber waste produced during manufacturing processes and discarded rubber containing products such as latex examining gloves and gaskets.The polymeric waste may generally be any kind of plastic waste, for example mixed plastic waste (MPW), automo- tive-shredder-residue (ASR), end-of-life tires (ELT), and / or plastic solid waste (PSW), present in municipal solid waste (MSW), electronic waste.The polymeric waste may be pre-treated for obtaining a feedstock that is particularly suitable for partial oxidation, e.g. by pyrolysis, for obtaining a pyrolysis oil.Preferably, the hydrocarbons or the mixture comprising hydrocarbons are selected from hydrocarbons or hydrocarbon mixtures having from 1 to 12 carbon atoms, preferably natural gas, methane, LPG, naphtha and mixtures thereof; pyrolysis oils, for example obtained from feedstocks of the recycling economy, especially from polymeric waste including end-of-life tires (ELT) waste; residual oil, e.g. from an oil refinery, petroleum coke, coal, asphalt, biomass; polymeric waste, preferably end-of-life tires (ELT) waste, mixed plastic waste (MPW), industrial plastic waste (I ), household plastic waste, electronic and electrical waste (E-waste), automotive plastic waste like automotive shredder residue (ASR) and mixtures thereof; and mixtures of the abovementioned hydrocarbons or mixtures comprising hydrocarbons.It is for example possible to use mixtures comprising pyrolysis oils, for example obtained from feedstocks of the recycling economy, especially from plastic waste including tires in combination with natural gas or methane as feedstock (i.e. hydrocarbons or mixtures comprising hydrocarbons according to the present invention. It is - however - alsopossible to use for example natural gas or methane as hydrocarbons or pyrolysis oils, for example obtained from feedstocks of the recycling economy, especially from plastic waste including tires as mixtures comprising hydrocarbons.Generally, fossil-based conventional hydrocarbons can be used as well as synthetic methane prepared by "Power-to- X” processes with CO2 and hydrogen as main raw materials. Preferably synthetic methane respectively the employed hydrogen is prepared using at least partially renewable energy and the CO2 raw material is preferably captured from industrial flue gases (Carbon Capturing) or air (e.g. Direct Air Capturing, DAC). Mixtures of fossil-based and synthetic hydrocarbons are preferred as well.In the case that natural gas is employed as hydrocarbon, every natural gas composition may be employed. Suitable natural gas contains for example at least 85 volume percent methane. The remaining components of such natural gas are usually ethane, propane, iso-butane, n-butane, n-pentane, iso-pentane and n-hexane.Further, the hydrocarbons may contain small amounts of other gases besides the hydrocarbons, especially nitrogen, carbon dioxide, carbon monoxide, water, hydrogen sulfide as well as noble gases such as helium and / or argon.The oxygen-comprising reactant gas according to the present invention comprises O2 and at least 1 ppmv of H2, more preferably 1 .5 to 20,000 ppmv of H2, most preferably 2 to 15,000 ppmv of H2 based on the total volume of the oxygen-comprising reactant gas.The oxygen-comprising reactant gas according to the present invention may comprise 0 to <0.5 Vol% H2O, preferably 0.1 to <1 Vol% H2O, more preferably 1 to <50000 ppmv H2O, further more preferably 2.5 to <2500 ppmv H2O, most preferably 5 to <1000 ppmv H2O based on the total volume of the oxygen-comprising reactant gas.The oxygen-comprising reactant gas according to the present invention may comprise 0 to <1500 ppmv N2, preferably 0.1 to <1000 ppmv N2, more preferably 0.5 to <500 ppmv N2 based on the total volume of the oxygen-comprising reactant gas. Most preferably, no N2 is present in the oxygen-comprising reactant gas.In the inventive process, generally a controlled amount of oxygen is added, usually less than the amount required for complete combustion. This ensures that carbon monoxide is produced in preference to carbon dioxide.The equivalence ratio of hydrocarbon to oxygen (in the oxygen comprising reactant gas) in the inventive process is preferably > 1, more preferably > 1 to 4, further more preferably 1.5 to 3.The term "equivalence ratio" is defined herein as the molar ratio of hydrocarbon to oxygen fed to the reactor relative to the molar ratio of hydrocarbon to oxygen required for complete combustion to CO and H2 (see the general equation for partial oxidation above). An equivalence ratio of 1 .0 is a stoichiometric mixture for converting all of the hydrocarbon to CO and H2. A mixture with an equivalence ratio < 1 is fuel-lean (excess oxygen), while a mixture with an equivalence ratio > 1 is fuel-rich (excess hydrocarbon).The oxygen comprising reactant gas employed in the process of the present invention is obtained at least in part by water electrolysis. The water electrolysis, preferably uses energy generated at least in part from non-fossil resources.The term "at least in part from non-fossil resources” means that part of the energy can still be produced from fossil fuels, preferably from natural gas, since combustion of natural gas causes much lower carbon dioxide emission per megajoule of energy produced than combustion of coal. However, the share of energy produced from fossil fuels should be as low as possible, preferably < 50%, more preferably < 30%, most preferably < 20%, further most preferably < 10% of the energy in the water electrolysis is generated from fossil resources. Further most preferably, the energy in the water electrolysis, is generated exclusively from non-fossil resources.Therefore, preferably, at least 50%, preferably at least 70%, more preferably at least 80%, further more preferably at least 90% and most preferably 100% of the total required energy input used in the water electrolysis, is generated from non-fossil resources.Preferably, the energy generated at least in part from non-fossil resources is selected from solar energy (thermal, photovoltaic and concentrated solar power), wind power, hydroelectricity (tidal power, wave power, hydroelectric dams, In-river-hydrokinetics), geothermal energy, heat captured by heat pumps, bioenergy (biofuel, biomass), the renewable part of waste energy sources, nuclear energy and mixtures thereof.In a further embodiment, the energy is generated at least in part from non-fossil resources selected from renewable resources, preferably selected from solar energy (thermal, photovoltaic and concentrated solar power), wind power, hydroelectricity (tidal power, wave power, hydroelectric dams, In-river-hydrokinetics), geothermal energy, heat captured by heat pumps, bioenergy (biofuel, biomass), the renewable part of waste and mixtures thereof.The types of energy resources mentioned above are generally known by a person skilled in the art.In one preferred embodiment of the inventive process, the energy from non-fossil resources used in the process according to the invention is generated at least in part by nuclear energy. The nuclear energy is generally obtained by fission.Fission occurs when a neutron enters a larger atomic nucleus, forcing it to excite and spilt into two smaller atoms— also known as fission products. Additional neutrons are also released that can initiate a chain reaction. When each atom splits, a tremendous amount of energy is released. Uranium and plutonium isotopes are most commonly used for fission reactions in nuclear power reactors because they are easy to initiate and control. The energy released by fission in these reactors heats water into steam. The steam is used to spin a turbine to produce carbon-free electricity.In one preferred embodiment of the inventive process, the energy used in the process according to the invention is generated at least in part from wind power. Wind power can be used to run wind turbines. Modern utility-scale wind turbines range from around 600 kW to 9 MW of rated power. The power available from the wind is a function of the cube of the wind speed, so as wind speed increases, power output increases up to the maximum output for the particular turbine. Areas where winds are stronger and more constant, such as offshore and high-altitude sites, are preferred locations for wind farms.In one further preferred embodiment of the inventive process, the energy used in the process according to the invention is generated at least in part from solar power, particularly preferred from photovoltaic systems. A photovoltaic system converts light into electrical direct current (DC) by taking advantage of the photoelectric effect. Concentrated solar power (CSP) systems use lenses or mirrors and tracking systems to focus a large area of sunlight into a small beam. CSP-Stirling currently has the highest efficiency among all solar energy technologies.In one preferred embodiment of the inventive process, the energy used in the process according to the invention is generated at least in part from hydropower. There are many forms of hydropower. Traditionally, hydroelectric power comes from constructing large hydroelectric dams and reservoirs. Small hydro systems are hydroelectric power installations that typically produce up to 50 MW of power. They are often used on small rivers or as a low-impact development on larger rivers. Run-of-the-river hydroelectricity plants derive energy from rivers without the creation of a large reservoir. The water is typically conveyed along the side of the river valley (using channels, pipes and / or tunnels) until it is high above the valley floor, whereupon it can be allowed to fall through a penstock to drive a turbine. Wave power, which captures the energy of ocean surface waves, and tidal power, converting the energy of tides, are two forms of hydropower with future potential.In one further preferred embodiment of the inventive process, the energy used in according to the invention is generated at least in part from geothermal energy. Geothermal energy is the heat that comes from the sub-surface of the earth. It is contained in the rocks and fluids beneath the earth's crust and can be found as far down to the earth's hot molten rock, magma.To produce power from geothermal energy, wells are dug a mile deep into underground reservoirs to access the steam and hot water there, which can then be used to drive turbines connected to electricity generators. There are three types of geothermal power plants; dry steam, flash and binary.Dry steam is the oldest form of geothermal technology and takes steam out of the ground and uses it to directly drive a turbine. Flash plants use high-pressure hot water into cool, low-pressure water whilst binary plants pass hot water through a secondary liquid with a lower boiling point, which turns to vapor to drive the turbine.In one further preferred embodiment of the inventive process, the energy used in the process according to the invention is generated at least in part from biomass. Biomass is biological material derived from living, or recently living organisms. It most often refers to plants or plant-derived materials which are specifically called lignocellulosic bio-mass. As an energy source, biomass can either be used directly via combustion to produce heat (e.g. heat from fermentation processes) or electricity, or indirectly after converting it to various forms of biofuel and gas. Conversion of biomass to biofuel can be achieved by different methods which are broadly classified into: thermal, chemical, and biochemical methods. Wood was the largest biomass energy source as of 2012; examples include forest residues - such as dead trees, branches and tree stumps -, yard clippings, wood chips and even municipal solid waste. Industrial biomass can be grown from numerous types of plants, including miscanthus, switchgrass, hemp, corn, poplar, willow, sorghum, sugarcane, bamboo, and a variety of tree species, ranging from eucalyptus to oil palm (palm oil).Plant energy is produced by crops specifically grown for use as fuel that offer high biomass output per hectare with low input energy. The grain can be used for liquid transportation fuels while the straw can be burned to produce heat or electricity. Biomass can be converted to other usable forms of energy such as methane gas or transportation fuels such as ethanol and biodiesel. Rotting garbage, and agricultural and human waste, all release methane gas - also called landfill gas or biogas. Crops, such as corn and sugarcane, can be fermented to produce the transportation fuel, ethanol. Biodiesel, another transportation fuel, can be produced from left-over food products such as vegetable oils and animal fats.Biopower technologies convert renewable biomass fuels into heat and electricity using processes like those used with fossil fuels. There are three ways to harvest the energy stored in biomass to produce biopower: burning, bacterial decay, and conversion to a gas or liquid fuel. Biopower can offset the need for carbon fuels burned in power plants, thus lowering the carbon intensity of electricity generation. Unlike some forms of intermittent renewable energy, biopower can increase the flexibility of electricity generation and enhance the reliability of the electric grid.Further preferably, at least part of the energy used in the process of the present invention is utilized from excess energy generated in other exothermic chemical processes than the process steps of the present invention (typical examples: acrylic acid, formaldehyde or ethylene oxide production), for example in a chemical "Verbund'' production setup distributing the excess energy e.g. as steam to endothermic process consumers. Excess steam can substitute steam generated by fossil fuels. Such a Verbund plant is preferably supplied with additional energy generated from non-fossil resources.Various methods for certification and tracking of the "energy source mix” have been set up based on local legislations. Certificates such as "Non-Fossil Certificate Contracts” are common practice for tracking the ratio of non-fossil energy used in industrial processes and related products (https: / / www.ekoenergy.org / ecolabel / criteria / tracking / ).Preparation (generation) of oxygen:The oxygen comprising reactant gas employed in the process of the present invention is obtained at least in part by water electrolysis. Mixtures with conventional oxygen from air separation (from the atmosphere) can also be employed.Preferably, at least 50%, more preferably at least 70%, further more preferably at least 80%, even further more preferably at least 90% and most preferably 100% of the total required oxygen comprising reactant gas is obtained by water electrolysis, wherein the water electrolysis, is preferably carried out using energy generated at least in part from non-fossil resources.It is also possible that the oxygen obtained by separation from the atmosphere is obtained at least in part or exclusively by energy generated from non-fossil resources.The water electrolysis, preferably uses energy generated at least in part from non-fossil resources. More preferably, the water electrolysis, exclusively uses energy generated from non-fossil resources.The term "at least in part from non-fossil resources” is explained above.The oxygen in the oxygen comprising reactant gas, which is obtained by water electrolysis, but using energy generated from fossil resources, may generally obtained by using any energy generated from fossil resources known in the art. A preferred fossil resource is natural gas, since combustion of natural gas causes much lower carbon dioxide emission per megajoule of energy produced than combustion of for example coal. However, the portion of energy produced from fossil fuels should be as low as possible in the process of the present invention. Most preferably the oxygen comprising reactant gas is fully obtained by water electrolysis, and the energy for the water electrolysis, is fully generated from non-fossil resources.Water electrolysis using energy based on renewable sources is an environmentally friendly method for production of oxygen because it uses renewable H2O and the oxygen is a surplus by-product, which is generally released into the environment, in the production of renewable hydrogen ("green hydrogen”). The electrolysis of 9 tons of water gives 1 ton of hydrogen and 8 tons of oxygen gas, but usually only the hydrogen is used as a value product. There are no further significant amounts of by-products in the water electrolysis.A recent review article gives a detailed overview of the currently most relevant technologies focusing on commercial large-scale implementation of water electrolysis for hydrogen production in the context of global energy transformation (H. Ozcan et al, Recent advances, challenges, and prospects of electrochemical water-splitting technologies for net-zero transition, Cleaner Chem. Eng. 8 (2023) 100115 - https: / / doi.Org / 10.1016 / j.clce.2023.100115).The most preferred water electrolysis generally utilizes as electrical power direct current (DC) at least in part from non-fossil energy resources.One suitable water electrolysis process is alkaline water electrolysis. Oxygen (and hydrogen) production by alkaline water electrolysis is a well-established technology up to the megawatt range for a commercial level. In alkaline water electrolysis initially at the cathode side two water molecules of alkaline solution (KOH / NaOH) are reduced to onemolecule of hydrogen (H2) and two hydroxyl ions (OH-). The produced H2 emanates from the cathode surface in gaseous form and the hydroxyl ions (OH-) migrate under the influence of the electrical field between anode and cathode through the porous diaphragm to the anode, where they are discharged to half a molecule of oxygen (O2) and one molecule of water (H2O). Alkaline electrolysis operates at lower temperatures such as 30-100°C with alkaline aqueous solution (KOH / NaOH) as the electrolyte, the concentration of the electrolyte being about 20% to 40 %. The diaphragm in the center of the electrolysis cell separates the cathode and anode and also separates the produced gases from their respective electrodes, avoiding the mixing of the produced gases.The operating temperature of the alkaline water electrolysis is typically around 80 °C and systems of up to 750 Nm3Fh / h are available. These systems use an aqueous solution of potassium hydroxide (KOH) as an electrolyte with a typical concentration of 20-40% and achieve current densities of 0.25-0.45 A / cm2. Rectangular and circular electrodes and cells with an active area of up to approximately 3 m2have also been used. Also pressurized electrolyzers are known (e.g. manufactured by Lurgi GmbH (Air Liquide Global E&C Solutions Germany GmbH)) that supply hydrogen and oxygen below 30 bar. Such pressurized electrolyzer produces 760 Nm3 / h of hydrogen, which corresponds to an electrical output of approximately 3.6 MW. Lifetimes of up to 90,000 h are achieved by the stack, with the electrodes and diaphragms needing to be replaced after this period.An overview of alkaline water electrolysis powered by renewable energy is given in J. Brauns and T. Turek in Processes, 8(2) (2020), pp. 248.In one further embodiment of the inventive process, oxygen (and hydrogen) is provided by polymer electrolyte membrane water electrolysis. Variants of polymer electrolyte membrane water electrolysis are proton exchange membrane water electrolysis (PEMWE, PEM water electrolysis) and anion exchange membrane water electrolysis (AEMWE, AEM water electrolysis).Low-temperature electrolysis processes based on alkaline and PEM technologies can be used to establish large, powerful systems (1-100 MW). In contrast to PEM electrolysis, a number of alkaline electrolysis designs have been used for several decades at various scales. However, polymer electrolyte membrane water electrolysis like PEM and AEM do have advantages over the alkaline electrolysis.According to the NOW study by the Fraunhofer Institute for Solar Energy Systems (ISE, Freiburg), the voltage efficiency of the stack amounts to 62-82% in relation to the higher heating value (HHV). At less than 20%, the lower partial load operation is especially critical for its flexible application in combination with renewable energy sources. This is a result of the diaphragms that are used, which facilitate the mixture of hydrogen and oxygen due to diffusion, which in turn leads to safety-related switch offs. Another disadvantage of alkaline electrolyzers as compared with PEM electrolysis is the costly gas treatment of the product gases, for which expensive noble metals must be used. In contrast to alkaline water electrolysis, PEM electrolysis with proton-conducting membranes uses platinum group metals for the electrodes. Due to the use of dense membranes as an electrolyte and the possibility of integration withrecombination catalysts, the systems can be operated at 0-100% power; however, in technical facilities the lower threshold is limited to approximately 5% of nominal power due to the internal consumption of peripheral components.All large PEM electrolysis manufacturers are working on the development of MW systems with various stack concepts. For instance, a 1 MW PEM electrolyzer with a single stack and a nominal power of 1 MW is known (Hydrogen- ics). For the most part, the commercially-available stacks only operate with current densities < 2.0 A / cm2. In these systems, approximately 6 mg / cm2of iridium or ruthenium is required for the anode, and approximately 2 mg / cm2of platinum is required for the cathode. In contrast to alkaline electrolysis, the lifetime of PEM electrolysis stacks is estimated at <20,000 h. However, PEM electrolysis stacks with a lifetime of more than 50,000 h are known (Proton Onsite; HOGEN C series).The PEM water electrolyzer utilizes a solid polymer electrolyte (SPE) to conduct protons from the anode to the cathode while insulating the electrodes electrically. Under standard conditions the enthalpy required for the formation of water is 285.9 kJ / mol. One portion of the required energy for a sustained electrolysis reaction is supplied by thermal energy and the remainder is supplied through electrical energy.The half reaction taking place on the anode side of a PEM water electrolyzer is commonly referred to as the Oxygen Evolution Reaction (OER). Here the liquid water reactant is supplied to a catalyst where it is oxidized to oxygen, protons and electrons.The half reaction taking place on the cathode side of a PEM water electrolyzer is commonly referred to as the Hydrogen Evolution Reaction (HER). Here the protons that have moved through the membrane are reduced to gaseous hydrogen.PEMs can be made from either pure polymer membranes or from composite membranes, where other materials are embedded in a polymer matrix. One of the most common and commercially available PEM materials is the fluoropolymer PFSA (e.g. Nation®, a DuPont product). While Nation® is an ionomer with a perfluorinated backbone like Teflon, there are many other structural motifs used to make ionomers for proton-exchange membranes. Many use polyaromatic polymers, while others use partially fluorinated polymers.An overview over PEM water electrolysis is given in S. Kumar and V. Himabindu, Material Science for Energy Technologies 2 (2019), pp. 4442 - 4454.The AEM water electrolysis technology adopts low-cost catalytic materials, as in alkaline electrolysis, and a solid polymer electrolyte architecture, as in PEM electrolysis technology. AEM electrolysis technology operates in an alkaline environment (pH ~ 10), making it possible the use modest non-noble-metal electrocatalysts (i.e. platin group metal free catalysts = PGM free catalysts), whilst accommodating a zero-gap architecture. The membrane used in this typeof electrolysis is a polymeric membrane, containing quaternary ammonium salts. It is relatively inexpensive and has low interaction with atmospheric CO2.Catalysts:As examples for hydrogen evolution reaction (HER) catalysts, catalysts based on Ni-Mo alloyed materials are suitable.As examples for oxygen evolution reaction (OER) catalysts, high activity of transition metal mixed oxides are suitable. Specific examples are CuxCo3_xO4, NiCo2O4:Fe and Ni-Fe alloys on Ni foam supports, for example the PGM- free catalysts (Ni-Fe, Ni-Mo, Ni / (CeO2-La2O3) / C and CuxCo3_xO4).Membranes and ionomers:The chemical stability of AEMs under alkaline conditions has improved markedly due to the development of stabilized functional groups on the polymer backbone. This allows the use of such membranes in AEM electrolysis at higher temperatures for long periods. Suitable membranes and ionomers are known by a person skilled in the art and for example described in the review mentioned below. One example is the commercial membrane Tokuyama A201.Membrane electrode assembly preparation and cell performance:The physical and electrochemical characterization of the membrane electrode assembly prepared by either the catalyst-coated substrate or the catalyst-coated membrane (COM) method suggests that the COM is preferable because improvements in ionic conductivity far outweigh any improvements in electronic conductivity.Liquid electrolyte: Pure water feeds generally result in poor current densities while 1 %K2CO3 or dilute KOH solutions give good results. A good electrolysis performance is achieved with a 1 % K2CO3 electrolyte. It is therefore preferable that the water electrolyte comprises 0.1 to 2 wt% K2CO3 or KOH.An overview over anion exchange membrane water electrolysis is given in H. A. Miller et al., Sustainable Energy Fuels, 2020, 4, pp. 2114 - 2133.Beside the alkaline water electrolysis, the AEM and PEM, a further commercially available electrolysis technology is the solid oxide electrolysis (SOE).SOEC (solid oxide electrolysis cell) feeds water into the cathode and the water undergoes water reduction reaction (WRR), which converts water into hydrogen gas and oxide ions. This hydrogen gas is later brought to purification modules to separate hydrogen gas from the remaining water. Then, the oxide ions migrate from cathode to anode and they release electrons to external circuit to become oxygen gas via oxygen evolution reaction (OER). Typically, the operating temperatures for SOFCs are from 800 to 1 ,000 °C, because high temperatures are required to thermally activate the migration of oxide ions and to facilitate electrochemical reactions on both electrodes. As a result,the overall efficiency is improved. The SOEC is for example described in K. Kamlungsua et al., FUEL CELLS 20, 2020, No. 6, 644-649.Preferably, the electrolysis for obtaining oxygen (and hydrogen) is a water electrolysis, more preferably PEM water electrolysis, alkaline water electrolysis, or AEM water electrolysis.In a further preferred embodiment, the electrolysis for obtaining oxygen (and hydrogen) is a solid oxide water electrolysis (SOE).The inventive partial oxidation is carried out non-catalytically (thermal partial oxidation (TPOX)) or catalytically (catalytic partial oxidation (CPOX), preferably non-catalytically.In CPOX the use of a catalyst generally reduces the required temperature (see below). The choice of reforming technique generally depends (among others) on the sulfur content of the hydrocarbons or the mixture comprising hydrocarbons being used. CPOX can generally be employed if the sulfur content is below 50 ppm. A higher sulfur content would poison the catalyst, so the TPOX procedure is generally used for such hydrocarbons or mixtures comprising hydrocarbons.Both, the non-catalytic and the catalytic process are generally known in the art and for example described in Makar- yan, I.A.; Salgansky, E.A.; Arutyunov, V.S.; Sedov, I.V. Non-Catalytic Partial Oxidation of Hydrocarbon Gases to Syngas and Hydrogen: A Systematic Review. Energies 2023, 16, 2916. https: / / doi.org / 10.3390 / en16062916 (non- catalytic partial oxidation) and Ruoshui Ma, Bang Xu, Xiao Zhang, Catalysis Today, November 2019, Volume 338, p.18-30 (catalytic partial oxidation).Generally, the partial oxidation is carried out at a temperature of 500 to 1600°C, preferably at a temperature of 500 to 1500°C.In the case of a non-catalytic partial oxidation, it is preferably carried out at 1000°C to 1600°C, preferably at 1100 to 1500°C.In the case of a catalytic partial oxidation, it is preferably carried out at 500°C to 1100°C, preferably at 600 to 1000°C.Generally, the partial oxidation is carried out at a pressure of 1 MPa to 20 MPa, preferably at a temperature of 1.5 MPa to 18 MPa.In the case of a non-catalytic partial oxidation, it is preferably carried out at 1 to 15 MPa, preferably at 1.5 to 14 MPa. In the case of a catalytic partial oxidation, it is preferably carried out at 1 to 6 MPa, preferably at 1.5 to 5 MPa.Suitable catalysts for the catalytic partial oxidation are known by a person skilled in the art and for example described in Nurherdiana, S.D., dkk. Akta Kimia Indonesia 6(2), 2021, 187-201.Examples for suitable catalysts are metal oxides, zeolites and perovskite oxides.Examples for suitable metals present in the catalysts for the catalytic partial oxidation are derived from two types: noble metal catalyst (Rh, Ru, Pt, Pd, Ir) and non-noble metal catalysts (Ag, Pt, Ni, Co).The catalysts for the catalytic partial oxidation are homogeneous or heterogeneous. Preferred are heterogeneous catalysts in the form of metal oxides, zeolites (such as ZSM-5, zeolite Y and zeolite A) and perovskites. Metal oxides used include for example AI2O3, NIC, Ce02.The active metal is contained in the catalysts for the catalytic partial oxidation generally in an amount of from 0.05% to 10.0% by weight per unit weight of the catalyst.Specific examples for catalysts for the catalytic partial oxidation are Ni / AhOa, Ni / Mg , Ni-Mg / AhOa, NiO-AhOa, Ni / zeo- lit Y, Ni-zeolit BEA, Pt / 10%Rh, Pt-CeO2, Ag / CGA, Lao eCac Feo zaCoo aaOa-s and Lao eSro^Tio aFeo gOa-g.The amount of catalyst can vary depending on the specific reaction setup, reactor design, and desired outputReacting the hydrocarbons or the mixture comprising hydrocarbons with an oxygen-comprising reactant gasIn a reaction apparatus for carrying out the partial oxidation processes the feedstocks (feedstock streams) are supplied thereto in any suitable manner through an inlet and the synthesis gas mixture obtained is leaving the reaction apparatus through an outlet.The feedstock streams - one stream comprising the hydrocarbons or mixtures comprising hydrocarbons and the other stream comprising the oxygen comprising reactant gas - are generally first preheated. The hydrocarbons or mixtures comprising hydrocarbons and the oxygen comprising reactant gas are preheated together or separately before pressurizing, preferably separately. The preheating temperature is dependent upon the hydrocarbons or mixtures comprising hydrocarbons used.The, preferably preheated, feedstocks are generally fed into a reaction apparatus (e.g. a gasifier) and partially oxidized at high temperatures and pressures, whereby a synthesis gas mixture is obtained. Suitable temperatures and pressures are mentioned above.The molar H2 / CO ratio may vary. It depends on the feedstock used and on the gasification method chosen. Preferably, the molar ratio of hydrogen and carbon monoxide (H2 / CO ratio) in the synthesis gas mixture is 0.6 - 4 : 1 , preferably 0.8 - 3.5 : 1.Suitable reaction apparatus (e.g. a gasifier) are known by a person skilled in the art.As used herein, a reaction apparatus can also be referred to as a "partial oxidation reactor”, a "gasification reactor," or simply a "gasifier" and these terms are often used equivalently and interchangeably. Further, the reaction apparatus can comprise one or more reactors.Examples for a suitable reaction apparatus are one or more flow reactors. Further examples for suitable reaction apparatus (partial oxidation reactors; gasifiers) are mentioned below.According to one example, the reaction apparatus consists of two zones. The first zone is the flame zone, where the hydrocarbons or the mixture comprising hydrocarbons and the oxygen comprising reactant gas react in the presence of a small amount of steam.The second zone is the heat exchange zone, in which the processes proceed due to the released heat of the oxidation reaction.In a further example, a reaction apparatus with a burner or a burner system is used in the inventive process. The feedstock streams - one stream comprising the hydrocarbons or mixtures comprising hydrocarbons and the other stream comprising the oxygen comprising reactant gas - are generally first preheated. Said preheated feedstocks are added separately or in form of a mixture to the burner or burner system, preferably separately. The oxygen comprising reactant gas supply rate generally exceeds the supply rate of the hydrocarbons or the mixture comprising hydrocarbons.Preferably, the inventive process comprises the following steps:(I) Introducing the hydrocarbons or a mixture comprising hydrocarbons and the oxygen-comprising reactant gas into a reaction apparatus; and(ii) Performing a partial oxidation reaction within said reaction apparatus by reacting the hydrocarbons or the mixture comprising hydrocarbons of step I) with the oxygen-comprising reactant gas, whereby a synthesis gas mixture comprising hydrogen and carbon monoxide and optionally carbon dioxide is formed.Suitable hydrocarbons or a mixture comprising hydrocarbons and, oxygen-comprising reactant gas, reaction apparatus, reaction conditions (O / C ratio, pressure, temperature) and H2 / CO ratio are mentioned above.The synthesis gas mixture can be cleaned and conditioned by known processes.Typical synthesis gas clean-up and conditioning processes include for example cyclones and filters for particulates removal for example followed by wet gas scrubbing to remove e.g. fine particulates, ammonia, and chlorides. Solid absorbents such as activated carbon may also be used to remove e.g. mercury and other trace heavy metals.The cleaning step mentioned above may in addition or as an alternative carried out after the preparation of the hydrogen enriched synthesis gas mixture (see below).Further conversion of the synthesis gas mixture like the oxo process or Fischer-Tropsch conversion of the cleaned syngas to produce methanol or liquid fuels is a possible next step in the inventive process. Further details regarding uses of the synthesis gas mixture obtained in the inventive process are mentioned below.H2 / CO ratios of industrial relevance are, for example, H2 / CO = 1.0: 1 for the oxo process (hydroformylation) or H2 / CO = 2.1 :1 for Fischer-Tropsch conversion (methanol synthesis).If the reaction apparatus (e.g. a gasifier) should produce a greater H2 / CO ratio than required, the excess H2 can be separated off for example by cryogenic distillative separation, by pressure swing adsorption or by membranes. The separated H2 is a product of value.If hydrogen (H2) is the target or the H2 / CO ratio of the synthesis gas mixture obtained is lower than required, i.e. if the reaction apparatus (e.g. a gasifier) should produce a synthesis gas with H2 / CO < 1.0: 1, the ratio can be raised by a downstream CO shift process (CO + H2OCO2 + H2) or by the addition of H2.The present invention therefore preferably comprises one or more process steps, wherein the ratio of hydrogen (H2) to carbon monoxide (CO) in the synthesis gas mixture comprising hydrogen and carbon monoxide and optionally carbon dioxide obtained in step ii) is increased for obtaining a hydrogen enriched synthesis gas mixture by one or both of the following alternatives a) adding hydrogen obtained at least in part by water electrolysis, the water electrolysis, preferably using energy generated at least in part from non-fossil resources; and / or b) feeding the synthesis gas mixture comprising hydrogen and carbon monoxide and optionally carbon dioxide obtained in step ii) to one or more water gas shift (WGS) reactors.The water gas shift reaction is known by a person skilled in the art.The water gas shift reaction can for example be carried out in two stages. The first is a high temperature shift (HTS) reactor which generally operates at 300-450 °C. Then comes the low temperature shift (LTS) reactor which generally operates at 180-230 °C. Steam injection can be used to optimise the reaction conditions and favour hydrogen production.The hydrogen can then be separated from the hydrogen enriched synthesis gas mixture by known processes. It is also possible to separate the hydrogen from the synthesis gas mixture obtained in the inventive process without one or more steps for increasing the hydrogen content.The separation of the hydrogen can be carried out by by pressure swing adsorption, membrane separation and / or cryogenic separation. Said processes are known by a person skilled in the art.The present invention therefore further relates to the inventive process, wherein hydrogen is separated from the hydrogen enriched synthesis gas mixture obtained according to alternative b) by pressure swing adsorption, membrane separation and / or cryogenic separation.The synthesis gas obtained in the inventive process a value product which is generally used for other purposes. Examples are feedstocks for the synthesis of chemical intermediates, such as methanol (Fischer-Tropsch conversion), OXO aldehydes (oxo process), etc. as well as power generation. Examples for uses of synthesis gases are known in the art and for example given in https: / / en.wikipedia.org / wiki / Syngas and below.The present invention therefore further relates to the inventive process, wherein the synthesis gas mixture comprising hydrogen and carbon monoxide and optionally carbon dioxide obtained in step ii) or the hydrogen enriched synthesis gas mixture is optionally cleaned and subsequently subjected to a Fischer Tropsch conversion or to an oxo process.Also, the synthesis gas is specific, due to the specific inventive process.Therefore, the present invention further relates to a synthesis gas obtainable or obtained by the process according to the present invention.According to the present invention, the oxygen-comprising reactant gas is obtained at least in part by by water electrolysis. As mentioned above, oxygen is produced as a by-product of water electrolysis, which is usually released into the environment without further use.In physical organic chemistry, a kinetic isotope effect is the change in the reaction rate of a chemical reaction when one of the atoms in the reactants is replaced by one of its isotopes. Formally, it is the ratio of rate constants ki_ I kn for the reactions involving the light (kJ and the heavy (kn) isotopically substituted reactants (isotopologues). This change in reaction rate is a quantum mechanical effect that primarily results from heavier isotopologues having lower vibrational frequencies compared to their lighter counterparts. In most cases, this implies a greater energetic input needed for heavier isotopologues to reach the transition state, and consequently, a slower reaction rate.Isotopic rate changes are most pronounced when the relative mass change is greatest, since the effect is related to vibrational frequencies of the affected bonds. For instance, changing a hydrogen atom (H) to its isotope deuterium (D) represents a 100 % increase in mass. However, isotope effects also exist for18O / 16O.It is observed that by the electrolysis of water, the180 atom content of the evolved oxygen gas is lower than the180 atom content in the oxygen obtained by separation from the atmosphere.The reason therefore is the kinetic isotope effect mentioned above, which is relevant in the present invention for two effects.First, in the electrolysis of water, the heavy oxygen18O content of the obtained oxygen gas is lower than in the water to be electrolyzed.Second, whereas the starting material of the oxygen obtained by separation from the atmosphere is ambient air, the starting material of the oxygen preferably used in the present invention is water ("water electrolysis”). However, the isotopic composition of atmospheric oxygen (18O / 16C>2) in air is enriched relative to (oceanic) water (Dole effect). Therefore, the heavy oxygen18O content of the oxygen obtained by water electrolysis is also for this reason lower than that of the oxygen obtained by separation from the atmosphere.The low heavy oxygen18O content of the electrolysis oxygen has also an impact on the downstream products, i.e. on the synthesis gas obtained in the inventive process as well as on the downstream products of said synthesis gas.The synthesis gas mixture comprising hydrogen (H2), carbon monoxide (CO), and optionally carbon dioxide (CO2), obtained in the inventive process preferably has a 518O value of < 22 %o, preferably, < 20 %o, more preferably < 18 %o, referred to the international standard VSMOW (Vienna- Standard- Mean-Ocean- Water), preferably obtained by the process according to the present invention.In - generally known - oxygen-18 isotope (18O) analysis, the absolute content is usually not determined, in contrast to the determination of chemical constituents.In the case of stable isotopes, an isotope abundance ratio (18O / 16O) is measured and compared with an international standard.The deviation of the isotope abundance ratio of the sample compared to that of the standard is given as 5 value in per thousand (%o). 518O values refer to the international standard VSMOW (Vienna- Standard- Mean-Ocean- Water). As the majority of natural waters contain fewer "heavy" isotopes than the reference, the 5 values are often negative. For the precise determination of the stable oxygen-18 only small sample quantities (a few ml) are required. The analytical measurement is carried out in a mass spectrometer (see the general method mentioned below).Vienna Standard Mean Ocean Water (VSMOW) is an isotopic water standard defined in 1968 by the International Atomic Energy Agency. Despite the somewhat misleading phrase "ocean water", VSMOW refers to pure water (H2O) and does not include any salt or other substances usually found in seawater. VSMOW serves as a reference standard for comparing hydrogen and oxygen isotope ratios, mostly in water samples. Very pure, distilled VSMOW water is also used for making high accuracy measurement of water's physical properties and for defining laboratory standards since it is considered to be representative of "average ocean water”, in effect representing the water content of Earth.The synthesis gas mixture obtainable or obtained in the inventive process can be used as value product, especially as feedstock for the synthesis of chemical intermediates.The present invention further relates to the use of the synthesis gas mixture obtained according to the process of the present invention for the preparation of methanol, fuel applications, formaldehyde, acetic acid, olefins, sodium methylate, methylation products, dimethylterephthalate, methylamine, methyl mercaptane, polyoxymethylene, butynediol, methylendiphenyldiisocyanate, neopentylglycol, phenol formaldehyde resins, urea-condensation resins, melamine resins, acetone resins, chloroacetic acid, acetic acid ester, methylisipropylketone, acetic acid anhydride, dimethylsulfide, methanesulfonic acid and downstream products.The present invention further relates to methanol, fuel applications, formaldehyde, acetic acid, olefins, sodium methylate, methylation products, dimethylterephthalate, methylamine, methyl mercaptane, polyoxymethylene, butynediol, methylendiphenyldiisocyanate, neopentylglycol, phenol formaldehyde resins, urea-condensation resins, melamine resins, acetone resins, chloroacetic acid, acetic acid ester, methylisipropylketone, acetic acid anhydride, dimethylsulfide, methanesulfonic acid and downstream products obtained from the inventive synthesis gas mixture or obtained from the synthesis gas mixture obtained according to the process of the present invention.Generally, the synthesis gas mixture according to the present invention and the downstream compounds based on said synthesis gas mixture, especially methanol, fuel applications, formaldehyde, acetic acid, olefins, sodium methylate, methylation products, dimethylterephthalate, methylamine, methyl mercaptane, polyoxymethylene, butynediol, methylendiphenyldiisocyanate, neopentylglycol, phenol formaldehyde resins, urea-condensation resins, melamine resins, acetone resins, chloroacetic acid, acetic acid ester, methylisipropylketone, acetic acid anhydride, dimethylsulfide, methanesulfonic acid and downstream products, comprise a 518O value which is lower that the 518O value of said compounds based on synthesis gas obtained by conventional methods not based on electrolysis oxygen.In a further embodiment, the present invention further relates to the use of the synthesis gas mixture obtained according to the process of the present invention for the preparation of formaldehyde, acetic acid, olefins, sodium methylate, methylation products, dimethylterephthalate, methylamine, methyl mercaptane, polyoxymethylene, butynediol, methylendiphenyldiisocyanate, neopentylglycol, phenol formaldehyde resins, urea-condensation resins, melamine resins, acetone resins, chloroacetic acid, acetic acid ester, methylisipropylketone, acetic acid anhydride, dimethylsulfide, methanesulfonic acid and downstream products.In a further embodiment, the present invention further relates to formaldehyde, acetic acid, olefins, sodium methylate, methylation products, dimethylterephthalate, methylamine, methyl mercaptane, polyoxymethylene, butynediol, methylendiphenyldiisocyanate, neopentylglycol, phenol formaldehyde resins, urea-condensation resins, melamine resins, acetone resins, chloroacetic acid, acetic acid ester, methylisipropylketone, acetic acid anhydride, dimethylsulfide, methanesulfonic acid and downstream products obtained from the inventive synthesis gas mixture or obtained from the synthesis gas mixture obtained according to the process of the present invention.Generally, the synthesis gas mixture according to the present invention and the downstream compounds based on said synthesis gas mixture, especially formaldehyde, acetic acid, olefins, sodium methylate, methylation products, dimethylterephthalate, methylamine, methyl mercaptane, polyoxymethylene, butynediol, methylendiphenyldiisocya- nate, neopentylglycol, phenol formaldehyde resins, urea-condensation resins, melamine resins, acetone resins, chloroacetic acid, acetic acid ester, methylisipropylketone, acetic acid anhydride, dimethylsulfide, methanesulfonic acid and downstream products, comprise a 518O value which is lower that the 518O value of said compounds based on synthesis gas obtained by conventional methods not based on electrolysis oxygen.Two important chemicals which can be obtained from synthesis gas mixture are methanol and formaldehyde.Methanol is a chemical building block for numerous products, including plastics, paints, car parts and construction materials. Methanol also is a clean energy resource.The processes for producing methanol from synthesis gas are classified according to the reaction pressure (high, medium and low pressure processes). Today, methanol is produced on an industrial scale from synthesis gas using low- or medium-pressure processes. Each process works with special catalysts and carbon monoxide / hydrogen ratios and under special reaction conditions. The exact reaction conditions and catalysts are known to the person skilled in the art.The crude methanol produced in both the low-pressure and medium-pressure processes is generally partially contaminated with by-products. If the crude methanol is used for combustion in the energy sector, the purity of the crude methanol is generally sufficient. For further processing in the chemical industry, the raw methanol is generally processed, usually by distillation. Low-boiling components such as dimethyl ether are generally separated in a low-boiling column. The higher-boiling fractions are usually separated off as a bottom in a further distillation stage, generally in a high-boiling column, with methanol usually being drawn off overhead.Suitable catalysts for the production of methanol from synthesis gas are known to those skilled in the art and are generally copper catalysts. Copper-zinc oxide-aluminum oxide catalysts are preferably used in both the low-pressure and medium-pressure processes, whereby the catalysts can be doped with cesium, for example. In the medium-pressure process, catalysts based on oxidic copper-chromium-zinc or chromium-zinc catalysts can also be used, for example.The copper-zinc oxide-aluminum oxide catalysts are generally produced according to processes known to the skilled person, e.g. by co-preci pitation starting from copper, zinc and aluminum hydroxycarbonates. Further steps include washing, ageing, drying, calcination and activation by reduction in a hydrogen / nitrogen stream, whereby the copper oxide produced during calcination is reduced to the metal. Suitable processes are known to the skilled person. The production of catalysts based on oxidic copper-chromium-zinc or chromium-zinc catalysts is also known to the skilled person.Low pressure process:The low-pressure process is generally carried out on the basis of the above-mentioned copper-zinc oxide-aluminum oxide catalysts. Dimethyl ether, formic acid methyl ester and ethanol, which are generally distilled off, are generally produced in the ppm range as by-products of the reaction.The low-pressure process is generally carried out at a pressure of 20 to 120 bar. The temperature is generally 200 to 300 °C.The reactor types used in the low-pressure process are, for example, fixed-bed tube bundle reactors in which the catalyst bed is located in tubes surrounded by boiling water. The tube diameter is generally designed in such a way that the temperature in the catalyst bed can be kept constant at around 5 to 10 °C. The resulting steam is used, for example, to heat the catalyst. The resulting steam is used, for example, to drive the compressors or to distil the raw methanol.Medium pressure process:The medium-pressure processes generally use both the above-mentioned copper-zinc oxide-alumina catalysts such as the low-pressure process and, for example, catalysts based on oxidic copper-chromium-zinc or chromium-zinc catalysts. A corresponding process works, for example, at a pressure of 100 to 250 bar. The temperature is generally 220 to 300 °C.In the processes mentioned above, the inventive synthesis gas mixture or the synthesis gas mixture obtained by the process according to the present invention is according to the present invention employed.The present invention therefore further relates to a process for preparing methanol from a synthesis gas mixture comprising: conversion of said synthesis gas mixture on a copper-containing catalyst, where the synthesis gas mixture is at least in part the inventive synthesis gas mixture or the synthesis gas mixture obtained by the process of the present invention.Suitable reaction conditions and catalysts employed in the process for preparing methanol are known by a person skilled in the art and mentioned above.The methanol obtained by the inventive process can be used for example as clean energy as well as for the preparation of downstream products, especially for the production of formaldehyde, acetic acid, and methyl tert-butyl ether.Formaldehyde is an important raw material for the chemical industry. Formaldehyde is used in the production of synthetic resins such as phenolic resins, urea resins and melamine resins, as well as in the production of polyols and polyoxymethylene. Formaldehyde is also used as a disinfectant and preservative and is used in numerous chemical synthesis processes. A large proportion of global methanol production is used for the synthesis of formaldehyde.According to the present invention, the formaldehyde is produced starting from the methanol produced according to the process of the invention.Formaldehyde (CH2O) is produced on an industrial scale by the catalytic oxidation of methanol with oxygen, generally atmospheric oxygen (air).Nowadays, two different large-scale processes are mainly used for this purpose: the formox process and the oxidative dehydrogenation of methanol. The processes are known in the art.Formox process:In the formox process, methanol is oxidized to form formaldehyde. In this process, methanol is generally mixed with an excess of atmospheric oxygen (air). The temperature is generally 250°C to 440°C. The preferred catalysts are iron oxide catalysts, molybdenum oxide catalysts or vanadium oxide catalysts. Preferably, oxides of molybdenum or iron are used in the catalyst at a molar ratio of 1 .5 to 2.0 (Mo:Fe), wherein small amounts of oxides of vanadium, cobalt, phosphorus, chromium, and copper may also be included.The reaction takes place for example in a fixed bed, vapor phase reactor.In a typical process methanol, fresh air, and recycle gas are mixed together and vaporized for example in a evapora- tor / vaporizer. The ratio of the recycled gas to fresh air is generally approximately 2.5: 1 . Generally, recycle of the offgas, which is rich in inerts, decreases the oxygen concentration and permits the use of relatively high methanol concentrations without creating an explosive mixture. Preferably, the oxygen concentration is kept at approximately 10 percent, while methanol is around six to nine percent, both on a molar basis.The warm reactor feed gas is fed to the reactor, which generally has tubes filled with catalyst.Methanol is oxidized over the metal oxide catalyst to form formaldehyde. Gas leaving the reactor generally consists largely of air and formaldehyde. In one design as an example, effluent gas is cooled from 250 °C to around 110 °C by indirect heat exchange in the evaporator before passing to the absorption column, where the formaldehyde is condensed and absorbed in the solution. The concentration of the solution can be varied from 37 to around 58 percent, depending upon the quantity of process water added and the tower design. Indirect cooling is supplied to the scrubbing plates and the process solution is recirculated through coolers at each stage of packing.Oxidative dehydrogenation:In the second production process, the oxidative dehydrogenation of methanol, silver catalysts are generally used. Two primary reactions occur during the conversion of methanol to formaldehyde (dehydrogenation and partial oxidation). The process is generally carried out at atmospheric pressure, generally with atmospheric oxygen. At temperatures of generally 600°C to 750°C, methanol is dehydrogenated to formaldehyde. During dehydrogenation, hydrogen atoms are split off from a chemical compound. The released hydrogen then reacts with atmospheric oxygen (air) to form water.The present invention therefore further relates to a process for preparing formaldehyde from a synthesis gas mixture comprising: oxidation of the methanol obtained in the inventive process mentioned above to formaldehyde with oxygen, air or a mixture thereof in the presence of a catalyst.The present invention further relates to a process for preparing formaldehyde from a synthesis gas mixture comprising:(A) conversion of said synthesis gas mixture on a copper-containing catalyst to methanol, where the synthesis gas mixture is at least in part the inventive synthesis gas mixture or the synthesis gas mixture obtained by the process of the present invention;(B) oxidation of the methanol to formaldehyde with oxygen, air or a mixture thereof in the presence of a catalyst.Suitable reaction conditions and catalysts employed in the process for preparing formaldehyde are known by a person skilled in the art and mentioned above.The formaldehyde obtained by the inventive process can be used for example in the production of urea formaldehyde (UF) resins, phenol formaldehyde (PF) resins, melamine formaldehyde (MF) resins, polyoxymethylenes (POM), methylene dephenyl diisocyanate (MDI), 1 ,4-butanediol (BDO), pentaerythritol (Penta), hexamine, and paraformaldehyde (PFA).The present invention further relates to a use of an oxygen-comprising reactant gas comprising at least 1 ppmv of H2 based on the total volume of the oxygen-comprising reactant gas, preferably obtained at least in part by water electrolysis, the water electrolysis preferably using energy generated at least in part from non-fossil resources for the preparation of a synthesis gas mixture comprising hydrogen and carbon monoxide and optionally carbon dioxide by partial oxidation of hydrocarbons or a mixture comprising hydrocarbons.Suitable hydrocarbons and mixtures comprising hydrocarbons and suitable processes for obtaining the oxygen-com- prising reactant gas and a suitable process for preparing the synthesis gas mixture are mentioned above. Further, preferred oxygen-comprising reactant gases are mentioned above.The present invention further relates to a partial oxidation reactor (POX reactor; also called gasifier in the context of the present invention) comprising a connection for supplying an oxygen-comprising reactant gas obtained at least in part by water electrolysis.Partial oxidation reactors are generally known in the art.The selection of partial oxidation reactor type and partial oxidation reactor size depends among others on physical and / or chemical properties of the feedstock. The physical and / or chemical properties are preferably selected from the group comprising water content, ash content, elemental composition, size, and calorific value. The selection of partialoxidation reactor type and partial oxidation reactor size also depends on the pre-treatment method applied to the feedstock. An overview of partial oxidation reactor (gasifier) types is for example provided in James G. Speight, Handbook of Gasification Technology, Scrivener Publishing and Wiley, 2020, chapter 8.4.2, pages 259 to 262.Suitable partial oxidation reactors comprise counter-current fixed bed reactors, co-current-fixed bed reactors, bubbling fluidized bed reactors, circulation fluidized bed reactors, and downdraft or updraft entrained flow reactors. The selection of size and reactor type depends on several parameters, including the composition of the feedstock, demand of products, moisture content and availability of the feedstock. The partial oxidation reactor is an „oxygen blown" gasifier, i.e. , oxygen is used as at least one oxidant in suitable partial oxidation reactor listed above. Another preferred type of partial oxidation reactors are plasma gasifiers, particularly fixed-bed plasma gasifiers. The electrical power required for generation of the plasma is most preferably provided from renewable energy sources such as solar energy, wind energy and tidal energy.Fluidized-bed gasifiers are preferred for small-grained solid feedstocks, preferably small-grained solid feedstocks having a particle size of no more than 6 mm. Entrained-flow gasifiers are preferred for liquid feedstocks and / or solid feedstocks preferably having a particle size of no more than 0.25 mm. Optionally, solid feedstocks are inserted into a gasifier in form of a slurry, e.g., a solid feedstock mixed with a liquid feedstock.The partial oxidation reaction in a partial oxidation reactor is typically carried out at a temperature > 700 °C in the presence of a sub-stoichiometric amount of an oxidant comprising oxygen or a mixture of oxygen with one or more of air, steam, supercritical water, CO2.The conversion of a feedstock in the partial oxidation reactor produces a syngas which consists primarily of H2, CO, and optionally one or more of CO2, methane, other hydrocarbons, and impurities. Said syngas has a dedicated molar ratio H2 : CO when leaving the partial oxidation reactor which ranges from about is 0.6 - 4 : 1, preferably 0.8 - 3.5 : 1 and generally depends on the type of solid and / or liquid feedstocks used, the oxidant and other reaction conditions applied such as temperature and / or residence time of the reactants in the partial oxidation reactor.System comprising a partial oxidation reactor (POX reactor) and a water electrolyzer connected by a gas pipe being a direct connection without any purification unit between the oxidation reactor and the water electrolyzer.Typical and preferred partial oxidation reactors (POX reactors; also called gasifiers in the context of the present invention) as well as typical and preferred electrolyzers are known in the art and mentioned above.Gas pipe connections between reactors suitable for delivering oxygen are known in the art.

Claims

CLAIMS1 . A process for producing a synthesis gas mixture comprising hydrogen and carbon monoxide and optionally carbon dioxide by partial oxidation of hydrocarbons or a mixture comprising hydrocarbons comprising: Reacting the hydrocarbons or the mixture comprising hydrocarbons with an oxygen-comprising reactant gas, wherein said oxygen-comprising reactant gas comprises at least 1 ppmv of H2 based on the total volume of the oxygen-comprising reactant gas, wherein the oxygen in the oxygen-comprising reactant gas is obtained at least in part by a water electrolysis without any further purification steps.

2. The process according to claim 1 , wherein the oxygen-comprising reactant gas comprises 1 .5 to 20,000 ppmv of H2, preferably 2 to 15,000 ppmv of H2 based on the total volume of the oxygen-comprising reactant gas.

3. The process according to claim 1 or 2, wherein the oxygen-comprising reactant gas according to the present invention comprises 0 to <0.5 Vol% H2O, preferably 0.1 to <1 Vol% H2O, more preferably 1 to <50000 ppmv H2O, further more preferably 2.5 to <2500 ppmv H2O, most preferably 5 to <1000 ppmv H2O based on the total volume of the oxygen-comprising reactant gas.

4. The process according to any one of claims 1 to 3, wherein the water electrolysis is carried out using energy generated at least in part from non-fossil resources.

5. The process according to any one of claims 1 to 4, wherein the hydrocarbons or the mixture comprising hydrocarbons is selected from hydrocarbons or hydrocarbon mixtures having from 1 to 12 carbon atoms, preferably natural gas, methane, LPG, naphtha and mixtures thereof; pyrolysis oils, especially from polymeric waste including end-of-life tires (ELT) waste; residual oil, e.g. from an oil refinery, petroleum coke, coal, asphalt, biomass; polymeric waste, preferably end-of-life tires (ELT) waste, mixed plastic waste (MPW), industrial plastic waste (I W), household plastic waste, electronic and electrical waste (E-waste), automotive plastic waste like automotive shredder residue (ASR) and mixtures thereof, and mixtures of the abovementioned hydrocarbons or mixtures comprising hydrocarbons.

6. The process according to any one of claims 1 to 5, wherein the partial oxidation is carried out non-catalytically or catalytically, preferably non-catalytically.

7. The process according to any one of claims 1 to 6, wherein the process comprises the following steps:(i) Introducing the hydrocarbons or a mixture comprising hydrocarbons and the oxygen-comprising reactant gas into a reaction apparatus; and(ii) Performing a partial oxidation reaction within said reaction apparatus by reacting the hydrocarbons or the mixture comprising hydrocarbons of step i) with the oxygen-comprising reactant gas, whereby a synthesis gas mixture comprising hydrogen and carbon monoxide and optionally carbon dioxide is formed.

8. The process according to any one of claims 1 to 7, wherein the partial oxidation is carried out at a temperature of 500 to 1600°C, preferably at 1000°C to 1600°C in the case of a non-catalytic partial oxidation and at 500 to 1100°C in the case of a catalytic partial oxidation.

9. The process according to any one of claims 1 to 8, wherein the partial oxidation is carried out at a pressure of 1 MPa to 20 MPa, preferably at 1 to 15 MPa in the case of a non-catalytic partial oxidation and at 1 to 6 MPa in the case of a catalytic partial oxidation.

10. The process according to any one of claims 1 to 9, wherein the molar ratio of hydrogen and carbon monoxide in the synthesis gas mixture is 0.6 - 4 : 1 , preferably 0.8 - 3.5 : 1 .11 . The process according to any one of claims 7 to 10, wherein the ratio of hydrogen to carbon monoxide (CO) in the synthesis gas mixture comprising hydrogen and carbon monoxide and optionally carbon dioxide obtained in step ii) is increased for obtaining a hydrogen enriched synthesis gas mixture by one or both of the following alternatives a) adding hydrogen obtained at least in part by water electrolysis, the water electrolysis, preferably using energy generated at least in part from non-fossil resources; and / or b) feeding the synthesis gas mixture comprising hydrogen and carbon monoxide and optionally carbon dioxide obtained in step ii) to one or more water gas shift (WGS) reactors.

12. The process according to claim 11, wherein hydrogen is separated from the hydrogen enriched synthesis gas mixture obtained according to alternative b) by pressure swing adsorption, membrane separation and / or cryogenic separation.

13. The process according to any one of claims 7 to 10, wherein the synthesis gas mixture comprising hydrogen and carbon monoxide and optionally carbon dioxide obtained in step ii) or the hydrogen enriched synthesis gas mixture obtained in claim 11 is optionally cleaned and subsequently subjected to a Fischer Tropsch conversion or to an oxo process.

14. The process according to any one of claims 1 to 13, wherein methanol is prepared from the synthesis gas mixture comprising the step: conversion of said synthesis gas mixture on a copper-containing catalyst.

15. The process according to any one of claims 1 to 13, wherein formaldehyde is prepared from the synthesis gas mixture comprising the steps:(A) conversion of said synthesis gas mixture on a copper-containing catalyst to methanol;(B) oxidation of the methanol to formaldehyde with oxygen, air or a mixture thereof in the presence of a catalyst.

16. Use of an oxygen-comprising reactant gas comprising at least 1 ppmv of H2 based on the total volume of the oxygen-comprising reactant gas for the preparation of a synthesis gas mixture comprising hydrogen and carbon monoxide and optionally carbon dioxide by partial oxidation of hydrocarbons or a mixture comprising hydrocarbons.

17. Use of the synthesis gas mixture prepared by the process according to any one of claims 1 to 13 for the preparation of formaldehyde, acetic acid, olefins, sodium methylate, methylation products, dimethylterephthalate, methylamine, methyl mercaptane, polyoxymethylene, butynediol, methylendiphenyldiisocyanate, neopentylglycol, phenol formaldehyde resins, urea-condensation resins, melamine resins, acetone resins, chloroacetic acid, acetic acid ester, methylisipropylketone, acetic acid anhydride, dimethylsulfide, methanesulfonic acid and downstream products.

18. Formaldehyde, acetic acid, olefins, sodium methylate, methylation products, dimethylterephthalate, methylamine, methyl mercaptane, polyoxymethylene, butynediol, methylendiphenyldiisocyanate, neopentylglycol, phenol formaldehyde resins, urea-condensation resins, melamine resins, acetone resins, chloroacetic acid, acetic acid ester, methylisipropylketone, acetic acid anhydride, dimethylsulfide, methanesulfonic acid and downstream products obtained from from the synthesis gas mixture prepared by the process according to any one of claims 1 to 13.

19. System comprising a partial oxidation reactor (POX reactor) and a water electrolyzer connected by a gas pipe, being a direct connection without any purification unit between the oxidation reactor and the water electrolyzer.

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