Low carbon intensity methanol production

Abstract

The present invention relates to a methanol plant and a process for the production of methanol in which a combination of a high temperature shift (HTS) section and a steam superheater can output a superheated steam stream which can be used to heat or pre-heat other sections or streams in the plant / process. Preheating of feeds and steam superheating by means of fired heaters can thus be reduced or avoided.

Description

[0001] LOW CARBON INTENSITY METHANOL PRODUCTION

[0002] TECHNICAL FIELD

[0003] The present invention relates to a methanol plant and a process for the production of methanol in which a combination of a high temperature shift (HTS) section and a steam superheater can output a superheated steam stream which can be used to heat or pre-heat other sections or streams in the plant / process. Preheating of feeds and steam superheating by means of fired heaters can thus be reduced or avoided .

[0004] BACKGROUND

[0005] In a typical syngas generation unit based on oxygen-fired reforming, preheating of feeds and steam superheating for turbine use is carried out by fired heater(s) by burning various offgases and natural gas. The major portion of the superheated steam is used for running turbines driving the large compressors in the plant.

[0006] To reduce the CO2 emissions pr. unit of methanol produced (carbon intensity) the carbon containing fuels can be replaced by hydrogen rich fuel as described in (WO 2022 / 248434) thus producing a CO2 rich export stream for sequestration. In some geographical locations, sequestration is not feasible and a layout without any fired heaters would therefore be attractive to produce methanol with low carbon intensity.

[0007] There is therefore a need to reduce the carbon intensity of methanol production and find solutions in the use of fired heaters is reduced or avoided.

[0008] SUMMARY

[0009] Processes for producing methanol based on ATR emit CO2 to the atmosphere through the burning of carbon containing fuel for preheating purposes in fired heater(s). The carbon intensity (CO2 emitted per ton of methanol produced) of such processes is approximately 0.3 tons of CO2 per ton of methanol.

[0010] It has been discovered that the carbon intensity of methanol production can be reduced significantly by using a combination of renewable energy and alternative preheating configuration to eliminate the fired heater. Further the present process does not produce a CO2rich export stream and is therefore especially applicable to methanol plants located in areas where CO2storage or CO2distribution infrastructure is not feasible or available.

[0011] In the present technology, a side stream of the syngas generated in the ATR taken downstream the WHB is passed through a high temperature shift reactor. As the shift reaction is exotherm the effluent can be used for superheating the steam generated in the upstream WHB. Part of the superheated steam can be used for preheating the feed to the prereformer and then the feed to desulfurization section. The de-superheated steam is introduced upstream the HTS to obtain the required steam / dry gas ratio for the HTS catalyst.

[0012] Preheat of the feed to the ATR can be eliminated as the ATR can operate directly on the prereformer effluent during normal operation on the cost of higher oxygen consumption. For start-up external heating source e.g. start-up electrical heater will be required to ignition temperature for the ATR. Since a large part of the superheated steam is used for preheating the main compressor will properly need to be electrical driven. If the power is from renewable sources the carbon intensity of the methanol product will decrease. The purge gas from the methanol synthesis before used as fuel can be partly recycled to the ATR to reduce export of carbon rich stream to OSBL while balancing the fuel requirement for the plant auxiliary boiler. The off-gas from the distillation can be routed to same location.

[0013] A methanol plant is provided. The methanol plant comprises: a hydrocarbon feed; a water feed; an oxygen feed; a feed pre-heater being arranged to pre-heat the hydrocarbon feed via heat exchange with at least a portion of a second superheated steam stream and to output a preheated hydrocarbon feed and a third superheated steam stream; a purification section, being arranged to remove sulfur compounds from the preheated hydrocarbon feed, and to output a purified hydrocarbon feed; a prereformer feed preheater arranged to heat said purified hydrocarbon feed and to output a heated purified hydrocarbon feed; a prereforming section arranged to pre-reform the heated purified hydrocarbon feed from the prereformer feed preheater in the presence of at least a portion of the superheated steam stream from the steam superheater, and to output a first syngas stream; an autothermal reforming section arranged to receive at least a portion of the first syngas stream from the prereforming section, and said oxygen feed and to output a second syngas stream; a steam generation section arranged to heat exchange at least a portion of the second syngas stream with the water feed and generate a third syngas stream and a first steam stream; a methanol synthesis section arranged to receive a first portion of the third syngas stream, and at least a portion of a fifth syngas stream, to generate a raw methanol stream, a first off gas stream and a second off-gas stream; a high temperature shift (HTS) section arranged to receive a second portion of the third syngas stream and a portion of the third superheated steam stream, and to generate a fourth syngas stream; a steam superheater arranged to superheat at least a portion of the first steam stream from the steam generation section via heat exchange with at least a portion of the fourth syngas stream from the HTS section; and to output a first superheated steam stream and a fifth syngas stream; wherein the prereformer feed preheater is arranged to heat said hydrocarbon feed via heat exchange with at least a portion of the first superheated steam stream from the steam superheater, and to output a second superheated steam stream.

[0014] A process for the production of methanol, in a methanol plant as described herein is also provided. The process comprises the steps of: a. providing a methanol plant according to any one of the preceding claims, b. heating the hydrocarbon feed in the feed pre-heater via heat exchange with at least a portion of a second superheated steam stream and outputting a preheated hydrocarbon feed and a third superheated steam stream; c. removing sulfur compounds from the preheated hydrocarbon feed in the purification section, and outputting a purified hydrocarbon feed; d. heating the purified hydrocarbon feed in the prereformer feed preheater and outputting a heated purified hydrocarbon feed; e. prereforming the heated purified hydrocarbon feed from the prereformer feed preheater in the prereforming section, in the presence of at least a portion of the superheated steam stream from the steam superheater, and outputting a first syngas stream; f. reforming at least a portion of the first syngas stream from the prereforming section, and said oxygen feed in the autothermal reforming section and outputting a second syngas stream; g. heat exchanging at least a portion of the second syngas stream with the water feed in the steam generation section and generating a third syngas stream and a first steam stream; h. feeding a first portion of the third syngas stream and at least a portion of a fifth syngas stream, to the methanol synthesis section and generating a raw methanol stream, a first off-gas stream, and a second off-gas stream; i. feeding a second portion of the third syngas stream and a portion of the third superheated steam stream, to a high temperature shift (HTS) section and generating a fourth syngas stream; j. superheating at least a portion of the first steam stream from the steam generation section via heat exchange with at least a portion of the fourth syngas stream output from the HTS section in a steam superheater; and outputting a first superheated steam stream and a fifth syngas stream; wherein the step of heating the hydrocarbon feed in the prereformer feed preheater takes place via heat exchange with at least a portion of the first superheated steam stream output from the steam superheater so as to output a second superheated steam stream.

[0015] Further details of the invention are set out in the following description, following figures, aspects and the dependent claims.

[0016] DRAWINGS

[0017] The technology is illustrated by means of the following schematic illustrations, in which:

[0018] Fig. 1 describes a layout of the methanol plant / process of the invention.

[0019] DETAILED DISCLOSURE

[0020] Unless otherwise specified, any given percentages for gas content are % by volume. All feeds are preheated as required.

[0021] A "section" comprises one or more "units" which perform a change in the chemical composition of a feed, and may additionally comprise elements such as e.g. heat exchanger, mixer or compressor, which do not change the chemical composition of a feed or stream.

[0022] The term "synthesis gas" (abbreviated to "syngas") is meant to denote a gas comprising hydrogen, carbon monoxide, carbon dioxide, steam and small amounts of other gasses, such as argon, nitrogen, methane, etc. A methanol plant is provided, as set out above.

[0023] A hydrocarbon feed is provided. This hydrocarbon feed suitably comprises a major portion of methane e.g. over 80%, such as over 90% of methane. Higher hydrocarbons (with >2 carbon atoms) may also be present. Suitably, the hydrocarbon feed is a natural gas feed. The hydrocarbon feed may also comprise low amount of argon, nitrogen, carbon dioxide, steam and sulfides.

[0024] A water feed is provided. This water feed suitably comprises a major portion of water e.g. over 99% water. Suitably, the water feed is demineralised and degassed.

[0025] An oxygen feed is provided. The oxygen feed is suitably "oxygen-rich" meaning that the major portion of this feed is O2; i.e. over 75% such as over 90% or over 95%, such as over 99% of this feed is O2. This oxygen feed may also comprise other components such as nitrogen, argon, CO2, and / or steam. This oxygen feed will typically include a minor amount of steam (e.g. 5-10%). Steam may be added to the oxygen feed, upstream the ATR. section.

[0026] A feed pre-heater is arranged to pre-heat the hydrocarbon feed via heat exchange with at least a portion of a second superheated steam stream (see below) and to output a preheated hydrocarbon feed and a third superheated steam stream. In other words, the second superheated steam stream provides heat to the hydrocarbon feed and its temperature is thereby lowered, to give the third superheated steam stream. The third superheated steam stream suitably has a temperature of between 270-330°C at the inlet of the HTS section.

[0027] A purification section is arranged to remove sulfur compounds from the preheated hydrocarbon feed, and to output a purified hydrocarbon feed. Sulfur may be present as sulfides in the hydrocarbon feed, however it is not desirable to have sulfur in the stream entering the (pre) reforming section, as the presence of sulfur typically leads to contamination of catalysts such as carbon formation on the surface of said catalyst. Suitable purification sections - e.g. a hydrodesulfurisation section - are known to the skilled person.

[0028] Prereformer feed preheater is arranged to heat the purified hydrocarbon feed and to output a heated purified hydrocarbon feed. The prereformer feed preheater is arranged to heat the hydrocarbon feed via heat exchange with at least a portion of the first superheated steam stream from the steam superheater (see below), and to output a second superheated steam stream. At this point, the temperature of the heated purified hydrocarbon feed outputted from the prereformer feed preheater is between 390-420°C. A prereforming section is arranged to pre-reform the heated purified hydrocarbon feed from the prereformer feed preheater in the presence of at least a portion of the superheated steam stream from the steam superheater, and to output a first syngas stream. Prereforming is the process by which methane and heavier hydrocarbons are steam reformed and the products of the heavier hydrocarbon reforming are methanated. A prereforming section may comprise an adiabatic pre-reformer filled with a catalyst with high nickel content. The adiabatic pre-reformer is usually positioned upstream of the main steam reformer. The first syngas stream provided comprises CO2, CH4, H2O and H2 along with typically lower quantities of CO and possible other components.

[0029] An autothermal reforming (ATR) section is arranged to receive at least a portion of the first syngas stream from the prereforming section, and said oxygen feed and to output a second syngas stream. The ATR section may comprise one or more ATR reactors. An ATR reactor typically comprises a burner, a combustion chamber, and a catalyst bed contained within a refractory lined pressure shell. In an ATR reactor, partial combustion of hydrocarbons by sub- stoichiometric amounts of an oxidant such as oxygen is followed by steam reforming (reaction 1 and 2) of the partially combusted hydrocarbons in a fixed bed of steam reforming catalyst.

[0030] CH4(g) + H2O (g) CO (g) + 3H2(g) (1)

[0031] CH4(g) + 2H2O (g) CO2(g) + 4H2(g) (2)

[0032] Steam reforming also takes place to some extent in the combustion chamber due to the high temperature. The steam reforming reaction is accompanied by the water gas shift reaction. Typically, the gas is at or close to equilibrium at the outlet of the reactor with respect to steam reforming and water gas shift reactions. More details of ATR and a full description can be found in the art such as "Studies in Surface Science and Catalysis, Vol. 152," Synthesis gas production for FT synthesis"; Chapter 4, p.258-352, 2004".".

[0033] The second syngas stream normally comprises hydrogen, carbon monoxide, carbon dioxide, and steam. Other components such as methane, nitrogen, and argon may also be present often in minor amounts. The operating pressure of the ATR section will be between 5 and 100 bars or more preferably between 15 and 60 bars.

[0034] Typically, the second syngas stream from the ATR section has a temperature of 900-1100 °C.

[0035] This heat can be advantageously used elsewhere in the plant. A steam generation section is therefore arranged to heat exchange at least a portion of the second syngas stream with the water feed and generate a third syngas stream and a first steam stream.

[0036] Methanol synthesis section is arranged to receive a first portion of the third syngas stream, and at least a portion of a fifth syngas stream, to generate a raw methanol stream, a first off gas stream and a second off-gas stream.

[0037] A high temperature shift (HTS) section is arranged to receive a second portion of the third syngas stream and a portion of the third superheated steam stream, and to generate a fourth syngas stream.

[0038] In a preferred aspect, the HTS section may comprise a promoted zinc-aluminum oxide based high temperature shift catalyst. Within this aspect, when said plant is operated the steam-to- carbon ratio in the reforming and HTS section are less than 2.6. The advantage of a low steam-to-carbon ratio within the reforming section and shift section is that it enables higher synthesis gas throughput compared to high steam-to-carbon ratio. Additionally, a low steam- to-carbon ratio requires smaller equipment in the front-end due to the lower total mass flow through the plant.

[0039] In preferred aspects, the temperature in the HTS section is in the range 300 - 600 °C, such as 300 - 400 °C, such as 340 - 380 °C.

[0040] A steam superheater is arranged to superheat at least a portion of the first steam stream from the steam generation section via heat exchange with at least a portion of the fourth syngas stream from the HTS section; and to output a first superheated steam stream and a fifth syngas stream. The prereformer feed preheater (mentioned above) is arranged to heat the hydrocarbon feed via heat exchange with at least a portion of the first superheated steam stream from the steam superheater, and to output a second superheated steam stream.

[0041] Depending on the natural gas feed, autothermal reforming will in many cases be substoichiometric for methanol formation i.e., M<2, and will therefore require hydrogen addition. In traditional ATR. plants with fired heater where purge and off-gas are used for fuel after hydrogen removal balance hydrogen from outside is not required. Without a fired heater, however, hydrogen from outside will most likely be required. In one aspect, therefore the methanol plant further comprises a hydrogen feed, said hydrogen feed being arranged to be fed to the methanol synthesis section, preferably in admixture with the first portion of the third syngas stream. Suitably, the methanol plant further comprises an electrolysis section arranged to provide said hydrogen feed. Preferably the electrolysis section is arranged to be powered by renewable energy, such as solar energy or wind energy.

[0042] In one aspect, the methanol plant, further comprises an electrical steam methane reformer (e-SMR), being arranged to generate the hydrogen feed in the form of a hydrogen rich syngas, preferably wherein the hydrogen rich syngas is arranged to superheat the third superheated steam stream.

[0043] Advantageously, at least a first part of the first off gas stream may be arranged to be recycled from the methanol synthesis section to the autothermal reforming section. The methanol plant may further comprise an off-gas recycle compressor being arranged to compress at least a portion of the second off-gas stream from the methanol synthesis section and recycle the compressed second off-gas stream to the autothermal reforming section.

[0044] A methanol distillation section is typically arranged to receive the raw methanol stream and output a purified methanol stream and a third off-gas stream.

[0045] In one aspect, at least a portion of the third off-gas stream is arranged to be recycled to the autothermal reforming section. This may improve carbon usage in the plant.

[0046] A process is provided for the production of methanol, in a methanol plant described herein. The process comprises the steps of: a. providing a methanol plant as defined herein, b. heating the hydrocarbon feed in the feed pre-heater via heat exchange with at least a portion of a second superheated steam stream and outputting a preheated hydrocarbon feed and a third superheated steam stream; c. removing sulfur compounds from the preheated hydrocarbon feed in the purification section, and outputting a purified hydrocarbon feed; d. heating the purified hydrocarbon feed in the prereformer feed preheater and outputting a heated purified hydrocarbon feed; e. prereforming the heated purified hydrocarbon feed from the prereformer feed preheater in the prereforming section, in the presence of at least a portion of the superheated steam stream from the steam superheater, and outputting a first syngas stream; f. reforming at least a portion of the first syngas stream from the prereforming section, and said oxygen feed in the autothermal reforming section and outputting a second syngas stream; g. heat exchanging at least a portion of the second syngas stream with the water feed in the steam generation section and generating a third syngas stream and a first steam stream; h. feeding a first portion of the third syngas stream and at least a portion of a fifth syngas stream, to the methanol synthesis section and generating a raw methanol stream, a first off-gas stream, and a second off-gas stream; i. feeding a second portion of the third syngas stream and a portion of the third superheated steam stream, to a high temperature shift (HTS) section and generating a fourth syngas stream; j. superheating at least a portion of the first steam stream from the steam generation section via heat exchange with at least a portion of the fourth syngas stream output from the HTS section in a steam superheater; and outputting a first superheated steam stream and a fifth syngas stream; wherein the step of heating the hydrocarbon feed in the prereformer feed preheater takes place via heat exchange with at least a portion of the first superheated steam stream output from the steam superheater so as to output a second superheated steam stream.

[0047] Suitably, the ratio of the portion of the third superheated steam stream to the second portion of the third syngas stream at the inlet of the high temperature shift section is 0.6-0.8.

[0048] In one aspect of the process, the module (M = (H2-CO2) / (CO+CO2)) of the syngas to the methanol synthesis section (i.e. the combined third and fifth syngas streams) is adjusted to a value of between 1.9 and 2.2 more preferably 2.00-2.10 by adding hydrogen. Dependent on natural gas feed, autothermal reforming will in many cases be substoichiometric for methanol formation i.e. M<2, and may therefore require hydrogen addition. In traditional ATR. plants with fired heater where purge and off-gas are used for fuel after hydrogen removal, balance hydrogen from outside is not required. With this layout without a fired heater, hydrogen from outside e.g. electrolysis will most likely be required.

[0049] In the process, the portion of the superheated steam stream from the steam superheater suitably has a temperature of between 420-450°C at the inlet of the prereforming section. The third superheated steam stream may have a temperature of between 270-330°C at the inlet of the HTS section.

[0050] All aspects of the methanol plant set out above are relevant for the process of the invention, mutatis mutandis. Specific embodiments

[0051] Methanol synthesis gas preferably has a composition corresponding to a so-called module (M = (H2-CO2) / (CO+CO2)) of 1.9-2.2 or more preferably slightly above 2 (eg.2.0-2.1).

[0052] Depending on the composition of the hydrocarbon feed stock, the module in the methanol synthesis gas from the autothermal reforming step can be lower than preferred value. In such circumstances hydrogen from e.g. water electrolysis can be added to the synthesis gas in order to adjust the module to the preferred value.

[0053] Thus, in an embodiment of the invention, module (M = (H2-CO2) / (CO+CO2)) of the methanol synthesis gas from step (e) is adjusted to a value of between 1.9 and 2.2 by adding hydrogen from electrolysis into the methanol synthesis gas.

[0054] As the preheat temperature to the ATR is lower by applying the invention the oxygen consumption will increase. If the compressors in the air separation unit is driven by renewable electricity the carbon intensity will remain unchanged.

[0055] The lower preheat temperature will also require a start-up heater for the ATR to ensure ignition. It is foreseen that this start-up heater is of electrical heater type.

[0056] EXAMPLE

[0057] An example of the invention in use is provided. Case 1 is with steam superheat and feed preheating using fired heaters and case 2 is applying the invention, as laid out in Figure 1. As it can be seen from the table, the carbon intensity of the methanol product can be reduced by 88.5% in present example.

[0058] The present invention has been described with reference to a number of aspects and figures. However, the skilled person is able to select and combine various aspects within the scope of the invention, which is defined by the appended claims. All documents mentioned herein are incorporated by reference.

Claims

CLAIMS1. A methanol plant (100), said plant (100) comprising : a hydrocarbon feed (1); a water feed (2); an oxygen feed (3); a feed pre-heater (90) being arranged to pre-heat the hydrocarbon feed (1) via heat exchange with at least a portion of a second superheated steam stream (42") and to output a pre-heated hydrocarbon feed (1') and a third superheated steam stream (42"'); a purification section (80), being arranged to remove sulfur compounds from the preheated hydrocarbon feed (1'), and to output a purified hydrocarbon feed (1"); a prereformer feed preheater (10) arranged to heat said purified hydrocarbon feed (1") and to output a heated purified hydrocarbon feed (1"'); a prereforming section (20) arranged to pre-reform the heated purified hydrocarbon feed (1"') from the prereformer feed preheater (10) in the presence of at least a portion of the superheated steam stream (42A) from the steam superheater (70), and to output a first syngas stream (21); an autothermal reforming section (30) arranged to receive at least a portion of the first syngas stream (21) from the prereforming section (20), and said oxygen feed (3) and to output a second syngas stream (31); a steam generation section (40) arranged to heat exchange at least a portion of the second syngas stream (31) with the water feed (2) and generate a third syngas stream (41) and a first steam stream (42); a methanol synthesis section (50) arranged to receive a first portion (41A) of the third syngas stream (41), and at least a portion of a fifth syngas stream (61'), to generate a raw methanol stream (51), a first off gas stream (52) and a second offgas stream (53); a high temperature shift (HTS) section (60) arranged to receive a second portion (41B) of the third syngas stream (41) and a portion of the third superheated steam stream (42'"), and to generate a fourth syngas stream (61); a steam superheater (70) arranged to superheat at least a portion of the first steam stream (42) from the steam generation section (40) via heat exchange with at least a portion of the fourth syngas stream (61) from the HTS section (60); and to output a first superheated steam stream (42', 42A) and a fifth syngas stream (61'); wherein the prereformer feed preheater (10) is arranged to heat said hydrocarbon feed (1") via heat exchange with at least a portion of the first superheated steamstream (42') from the steam superheater (70), and to output a second superheated steam stream (42").

2. The methanol plant (100) according to claim 1, further comprising a hydrogen feed (4), said hydrogen feed (4) being arranged to be fed to the methanol synthesis section (50), preferably in admixture with the first portion (41A) of the third syngas stream (41).

3. The methanol plant (100) according to any one of the preceding claims, further comprising an electrolysis section arranged to provide said hydrogen feed.

4. The methanol plant (100) according to any one of the preceding claims wherein the electrolysis section is arranged to be powered by renewable energy.

5. The methanol plant (100) according to any one of the preceding claims, further comprising an electrical steam methane reformer (e-SMR), being arranged to generate the hydrogen feed in the form of a hydrogen rich syngas, preferably wherein the hydrogen rich syngas is arranged to superheat the third superheated steam stream (42"').

6. The methanol plant (100) according to any one of the preceding claims, wherein at least a first part (52A) of the first off gas stream (52) is arranged to be recycled from the methanol synthesis section (50) to the autothermal reforming section (30).

7. The methanol plant (100) according to any one of the preceding claims, further comprising an off-gas recycle compressor (13) being arranged to compress at least a portion of the second off-gas stream (53) from the methanol synthesis section (50) and recycle the compressed second off-gas stream (53) to the autothermal reforming section (30).

8. The methanol plant (100) according to any one of the preceding claims, further comprising a methanol distillation section (110) being arranged to receive the raw methanol stream (51) and output a purified methanol stream (111) and a third off-gas stream (112).

9. The methanol plant (100) according to any one of the preceding claims, wherein at least a portion (112A) of the third off-gas stream (112) is arranged to be recycled to the autothermal reforming section (30).

10. The methanol plant (100) according to any one of the preceding claims, wherein the hydrocarbon feed (1) is a natural gas feed.

11. A process for the production of methanol, in a methanol plant according to any one of the preceding claims, said process comprising the steps of: a. providing a methanol plant according to any one of the preceding claims, b. heating the hydrocarbon feed (1) in the feed pre-heater (90) via heat exchange with at least a portion of a second superheated steam stream (42") and outputting a pre-heated hydrocarbon feed (1') and a third superheated steam stream (42"'); c. removing sulfur compounds from the preheated hydrocarbon feed (1') in the purification section (80), and outputting a purified hydrocarbon feed (1"); d. heating the purified hydrocarbon feed (1") in the prereformer feed preheater (10) and outputting a heated purified hydrocarbon feed (1"'); e. prereforming the heated purified hydrocarbon feed (1"') from the prereformer feed preheater (10) in the prereforming section (20), in the presence of at least a portion of the superheated steam stream (42A) from the steam superheater (70), and outputting a first syngas stream (21); f. reforming at least a portion of the first syngas stream (21) from the prereforming section (20), and said oxygen feed (3) in the autothermal reforming section (30) and outputting a second syngas stream (31); g. heat exchanging at least a portion of the second syngas stream (31) with the water feed (2) in the steam generation section (40) and generating a third syngas stream (41) and a first steam stream (42); h. feeding a first portion (41A) of the third syngas stream (41) and at least a portion of a fifth syngas stream (61'), to the methanol synthesis section (50) and generating a raw methanol stream (51), a first off-gas stream (52), and a second off-gas stream (53); i. feeding a second portion (41B) of the third syngas stream (41) and a portion of the third superheated steam stream (42'"), to a high temperature shift (HTS) section (60) and generating a fourth syngas stream (61); j. superheating at least a portion of the first steam stream (42) from the steam generation section (40) via heat exchange with at least a portion of the fourth syngas stream (61) output from the HTS section (60) in a steam superheater (70); and outputting a first superheated steam stream (42') and a fifth syngas stream (61'); wherein the step of heating the hydrocarbon feed (1) in the prereformer feed preheater (10) takes place via heat exchange with at least a portion of the first superheated steam stream (42') output from the steam superheater (70) so as to output a second superheated steam stream (42").

12. The process according to claim 11, wherein the ratio of the portion of the third superheated steam stream (42"') to the second portion (41B) of the third syngas stream (41) at the inlet of the high temperature shift section (60) is 0.6-0.

813. The process according to any one of claims 11-12, wherein of claim 1, wherein the module (M = (H2-CO2) / (CO+CO2)) of the syngas to the methanol synthesis section (50) is adjusted to a value of between 1.9 and 2.2 more preferably 2.00-2.10 by adding hydrogen(4).

14. The process according to any one of claims 11-13, wherein the portion of the superheated steam stream (42A) from the steam superheater (70) has a temperature of between 420-450°C at the inlet of the prereforming section (20).

15. The process according to any one of claims 11-14, wherein the third superheated steam stream (42"') has a temperature of between 270-330°C at the inlet of the HTS section.

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