GB2084973A

GB2084973A - An integrated process for the production of methanol and ammonia

Info

Publication number: GB2084973A
Application number: GB8032232A
Authority: GB
Original assignee: Toyo Engineering Corp
Current assignee: Toyo Engineering Corp
Priority date: 1980-10-07
Filing date: 1980-10-07
Publication date: 1982-04-21
Also published as: GB2084973B

Abstract

The process comprises the steps of subjecting a gaseous hydrocarbon feed to primary reforming with steam to produce a methanol synthesis gas containing H2 and CO, producing methanol from this methanol synthesis gas in a synthesizer, subjecting a purge gas extracted from the methanol synthesizer to secondary reforming with steam and air to produce an ammonia synthesis gas containing H2, N2, CO and CO2, subjecting this ammonia synthesis gas to high temperature shift conversion for the purpose of reducing its CO content, and thereafter passing the CO-impoverished ammonia synthesis gas through a series of steps to remove carbon oxides, the resulting ammonia synthesis gas then being fed to an ammonia synthesizer (26). Removal of oxides of carbon involves absorption of CO2, an additional methanol synthesis and methanation. Alternatively, if the gas stream leaving the high temperature shift converter is subjected to a low temperature shift conversion, removal of oxides of carbon can simply involve CO2 absorption and methanation.

Description

SPECIFICATION An integrated process for the production of methanol and ammonia This invention relates to an integrated process for the production of methanol and ammonia, from a gaseous hydrocarbon feed.

The combined production of methanol and ammonia from a hydrocarbon feed is well known as is disclosed in U.S. Patent No. 3,598,527. According to the process of this U.S. Patent, natural gas is subjected to primary reforming with steam and to secondary reforming with steam and an oxygencontaining gas, so that a methanol synthesis gas containing hydrogen, carbon monoxide and nitrogen is produced. This methanol synthesis gas is then subjected to low pressure methanol synthesis. The effluent stream from this methanol synthesis step is separated into crude methanol and a purge gas.

While the crude methanol is purified to obtain product methanol, the purge gas is subjected to high temperature and low temperature water-gas shift conversion whereby the carbon monoxide contained therein is converted into hydrogen and carbon dioxide. The gas resulting from this water-gas shift conversion step is freed of carbon oxides to a subtantially compiete degree by passing it through carbon dioxide removal and methanation steps, compressed to a desired ammonia synthesis pressure, and then subjected to ammonia synthesis.

When compared with the separate production of methanol and ammonia, the above-described process has several advantages such as lowered capital investment and reduced operating costs.

However, it still remains to be improved in some respects. More specifically, since a methanol synthesis gas is produced by both primary reforming and secondary reforming, it contains nitrogen which is unnecessary for methanol synthesis. This lowers the effective pressure for methanol synthesis.

Moreover, the presence of nitrogen requires the capacities of the plant's methanol synthesis tube, methanol synthesis gas compressor and circulating gas pump to be increased in proportion to the nitrogen content. Furthermore, during methanol synthesis, the nitrogen present in the methanol synthesis gas tends to form methylamines as impurities, thus complicating the purification of crude methanol It is an object of the present invention to provide an improved integrated process for the production of methanol and ammonia, wherein preferably the methanol to ammonia production ratio can be varied widely.

As indicated, it is desired to provide a process which involves substantially no risk of forming methylamines as impurities.

According to the present invention, there is provided an integrated process for the production of methanol and ammonia which comprises the steps of (a) subjecting a gaseous hydrocarbon feed to primary reforming with steam in the presence of a hydrocarbon reforming catalyst to produce a methanol synthesis gas containing hydrogen and carbon monoxide; (b) subjecting the methanol synthesis gas to methanol synthesis and then separating from the resulting methanol a purge gas containing hydrogen, carbon monoxide, carbon dioxide and methane; (c) Subjecting the purge gas to secondary reforming with steam and an oxygen-containing gas to produce an ammonia synthesis gas containing hydrogen, carbon monoxide, carbon dioxide and nitrogen; (d) subjecting the ammonia synthesis gas to high temperature shift conversion and thereby converting the carbon monoxide into carbon dioxide;; (e) passing the resulting carbon monoxide-impoverished ammonia synthesis gas through a series of steps required for the removal of carbon oxides; and (f) subjecting the resulting ammonia synthesis gas to ammonia synthesis.

The invention will now be described in more detail by way of example only with reference to the accompanying drawings, in which: Fig. 1 is a schematic flowsheet illustrating one embodiment of the present invention; and Fig. 2 is a schematic flowsheet illustrating another embodiment of the present invention.

The gaseous hydrocarbon feed used in the process of the present invention can be one or more members selected from hydrocarbons containing 1 to 4 carbon atoms. A typical example of the gaseous hydrocarbon feed is natural hydrocarbon gas mixture composed mainly of methane.

The primary reforming of the gaseous hydrocarbon feed is generally carried out under such conditions that the effluent stream leaving the reforming zone has a pressure of 1 5 to 40 kg/cm2 gauge and a temperature of 8000 to 9000 C. In view of the decomposition rates of hydrocarbons and the selection of equipment materials, however, it is particularly preferable to carry out the primary reforming under such conditions that the effluent stream leaving the reforming zone has a pressure of 1 7 to 20 kg/cm2 gauge and a temperature of 8500 to 9000C.

The methanol synthesis process used in the present invention is preferably a low pressure methanol synthesis process employing a pressure of 40 to 100 kg/cm2 gauge, in view of the pressure at which the purge gas resulting from the methanol synthesis process is subjected to secondary reforming.

The purge gas resulting from the methanol synthesis process is then subjected to secondary reforming with steam and an oxygen-containing gas (for example, air). This secondary reforming is carried out at an outlet pressure of 39 to 49 kg/cm2 and at an outlet temperature of 1,000 to 1 ,0500C.

Where the purge gas has a high methane content, it may be subjected to additional primary reforming with steam and then to secondary reforming. Moreover, where both primary reforming and secondary reforming are employed, an additional hydrocarbon feed may be added to the purge gas according to the required ammonia production rate. Usually, air is used as the oxygen-containing gas. However, a mixture of oxygen and air in any desired proportion may be used if it it necessary for the purpose of achieving a hydrogen to nitrogen ratio of 3:1 in the gas resulting from the secondary reforming step.

The gas resulting from the secondary reforming step is then subjected to high temperature shift conversion whereby the carbon monoxide contained therein is converted into hydrogen and carbon dioxide. Thereafter, the gas is subjected to a procedure for the removal of carbon oxides, so that the small amounts of carbon monoxide and carbon dioxide contained therein are removed from the remainder of the gas.

For the removal of carbon oxides, either of the following two procedures comprising a series of steps may be employed. According to one of them, the gas resulting from the high temperature shift conversion step is passed through waste heat recovery equipment, subjected to a carbon dioxide removal step, compressed (for example, to a pressure of 100 to 300 kg/cm2 gauge and preferably a pressure equal to the ammonia synthesis pressure) by means of a compressor, and then subjected to methanol synthesis in the presence of a methanol synthesis catalyst to convert almost all of the carbon monoxide and carbon dioxide into methanol.Thereafter, the gas resulting from this methanol synthesis step, which contains hydrogen, nitrogen, methane, argon, and very small amount of carbon monoxide and carbon dioxide, is subjected to conventional methanation whereby the residual carbon monoxide and carbon dioxide are converted into methane.

Another procedure is the one which is commonly employed in the production of an ammonia synthesis gas. More specifically, the gas resulting from the high temperature shift conversion step is freed of carbon oxides by passing it through a series of steps including low temperature shift conversion, carbon dioxide removal and methanation. This procedure is more fully described, for example, in U.S.

Patent No. 3,598,527.

After subjection to the above-described procedure for the removal of carbon-oxides, the gas is subjected to ammonia synthesis, for example, at a pressure of 100 to 300 kg/cm2 gauge and a temperature of 3800 to 5000C.

The present invention will now be described in more detail with reference to Figs. 1 and 2.

Referring first to Fig. 1 , there is illustrated an embodiment of the invention in which the procedure for the removal of carbon oxides comprises carbon dioxide removal, methanol synthesis and methanation. In the embodiment of Fig. 1, a hydrocarbon feed or natural gas under pressure is introduced through a pipeline 1, combined with ahydrogenation gas fed through a pipeline 7, and then preheated to a temperature of the order of 4000C. Thereafter, in order to hydrogenate sulfur compounds which are poisonous to the catalysts used for reforming with steam, methanol synthesis and ammonia synthesis and then remove the resulting products by adsorption, the natural gas is passed through desulfurization equipment 2 containing e.g. Co-Mo catalyst or zinc oxide.

Steam is fed through a pipeline 3 and added to the desulfurized natural gas in an amount of 2 to 4 moles per atomic weight of the carbon contained therein. The resulting natural gas-steam mixture is heated to a temperature of the order of 6000C and then introduced into a primary reformer 4 where, under the influence of a nickel catalyst, most of the natural gas is decomposed into hydrogen, carbon monoxide and carbon dioxide. This primary reforming is carried out under such conditions that the effluent stream leaving the primary reformer 4 has a pressure of 1 5 to 40 kg/cm2 gauge and a temperature of 8000 to 9000 C.

After leaving the primary reformer 4, the hot reformed gas flows into waste heat recovery equipment 5 where the waste heat recovered therefrom is utilized for the generation of steam, for the preheating of boiler feedwater, as a heat source for the distillation of crude methanol, and for other purposes. Thereafter, the hot reformed gas is cooled to ordinary temperature and the resulting condensate is separated therefrom. The cooled reformed gas, which now constitutes a methanol synthesis gas, enters a compressor 6 where it is compressed to a pressure of 40 to 100 kg/cm2 gauge.

A portion of the methanol synthesis gas leaving the compressor 6 is returned through the pipeline 7 to the desulfurization equipment 2 and used as a hydrogenation gas.

The remainder of the methanol synthesis gas is introduced into methanol synthesis equipment 8, combined with the gas circulating within this equipment, compressed to 40 to 100 kg/cm2 gauge as necessary by means of a circulator, and preheated. Then, the thus pressurised methanol synthesis gas flows into a methanol synthesis converter containing a conventional copper catalyst (for example, a Cu Zn or Cu-An-Cr catalyst), where methanol is synthesized at a temperature of 2400 to 2700 C.

The effluent gas stream from the methanol synthesis converter is cooled to effect condensation of crude methanol. The condensed and separated crude methanol is introduced into methanol distillation equipment 9 where high-boiling and low-boiling impurites are removed therefrom. Thus, refined methanol is withdrawn through a pipeline 1 0.

On the other hand, a portion of the gas stream from which crude methanol has been removed is discharged as a purge gas through a pipeline 11 in order to avoid accumulation of methane, nitrogen and other materials which do not take part in methanol synthesis. The remainder of the gas stream, which constitutes a circulating gas, is combined with methanol synthesis gas and reused for methanol synthesis. It is to be understood that, in some cases, the methanol synthesis equipment involves no gas circulation and all of the gas stream from which crude methanol has been separated is fed as a purge gas to the next step.

The aforesaid purge gas preferably comprises 70 to 80 mole % of hydrogen, 10 to 20 mole % of methane, 1 to 2 mole % of carbon monoxide, 1 to 2 mole % of carbon dioxide, 0 to 1 mole % of methanol, and 0 to 5 mole % of nitrogen.

The purge gas fed through the pipeline 11 is ultimately used as the raw material for ammonia synthesis. After this purge gas is preheated to a temperature of the order of 300"C, steam fed through a pipeline 12 is added thereto in an amount of 3 to 4 moles per atomic weight of the carbon contained therein. The resulting purge gas-steam mixture is further heated to a temperature of 5000C and introduced into a primary reformer 1 3.

Within the primary reformer 13, the methane and methanol present in the purge gas are decomposed with steam in the presence of a nickel catalyst and a portion thereof is converted into hydrogen, carbon monoxide and carbon dioxide. This primary reforming is carried out under such conditions that the process stream leaving the primary reformer 1 3 has a pressure of 40 to 50 kg/cm2 gauge and a temperature of 8300 to 9000C.

After leaving the primary reformer 13, the hot process stream is immediately introduced into a secondary reformer 14. On the other hand, air is compressed to a pressure of 40 to 50 kg/cm2 gauge by means of an air compressor 16, heated to a temperature of 6500 to 8500C, and then fed through a pipeline 1 5 to the secondary reformer 14.

Within the secondary reformer 14, the methane, hydrogen and carbon monoxide present in the hot process stream are partially burned with the oxygen contained in the air. Also within the secondary reformer 14, most of the methane is reacted with steam and thereby decomposed into hydrogen, carbon monoxide and carbon dioxide. The Hot process stream leaving the secondary reformer 14 has a pressure of 39 to 49 kg/cm2 gauge and a temperature of 1,0000 to 1 ,0500 C.

Depending on the methane content of the purge gas resulting from the methanol synthesis step, the primary reformer 1 3 may be omitted. Alternatively, if it is desired to increase the ammonia production rate, a make-up natural gas feed may be added through a pipeline 1 a to the purge gas introduced into the primary reformer 13.

The hot process stream leaving the secondary reformer 14 is then introduced into waste heat recovery equipment 1 7 where waste heat is recovered in the form of high pressure steam. The process stream leaving the waste heat recovery equipment 1 7 is maintained at a temperature of 3500 to 3700C and subsequently fed to a high temperature shift converter 1 8 containing an iron-chromium catalyst.

Under the influence of this catalyst, the carbon monoxide and steam present in the process stream emerging from the secondary reformer 14 are converted into hydrogen and carbon dioxide, so that the process stream leaving the high temperature shift converter 1 8 has a depleted carbon monoxide content of approximately 2.0 to 2.5 mole % (on a dry gas basis).

The process stream leaving the high temperature shift converter 18, which is a hot gaseous mixture having a temperature of 4000 to 4200C, then enters waste heat recovery equipment 1 9 where the waste heat recovered therefrom is utilized for the generation of high pressure steam, the preheating of boiler feedwater, the preheating of the gas stream fed to a methanator, and for other purposes.

Furthermore, the waste heat is also utilized as a heat source for the separation of product ammonia in an absorption refrigerator.

After being cooled in the waste heat recovery equipment 19, the process stream flows into carbon dioxide removal equipment 20 where the carbon dioxide present in the process stream is removed by passing the process stream through monoethanolamine, an aqueous solution of potassium carbonate, or other absorbing fluids. Thus, the carbon dioxide content of the process stream is reduced to 1 to 2 mole % (on a dry gas basis).

The process stream leaving the carbon dioxide removal equipment 20 is subsequently compressed to a pressure of approximately 100 to 300 kg/cm2 gauge by means of a compressor 21. Then, the compressed process stream enters methanol synthesis equipment 22 where it is preheated and passed through a methanol synthesis converter containing a methanol synthesis catalyst (for example, the aforesaid copper catalyst). Under the influence of this catalyst and at a temperature of 2100 to 2700 C, the carbon monoxide and carbon dioxide present in the process stream are reacted with hydrogen to produce methanol. The process stream leaving the methanol synthesis converter has a carbon monoxide content of as low as 0.1 to 0.5 mole % and a carbon dioxide content of as low as 0.3 to 0.5 mole % (on a dry gas basis).

In some cases, this methanol synthesis step may be carried out by withdrawing the process stream from an intermediate stage of the aforesaid compressor 21 and passing it through the methanol synthesis equipment 22.

The methanol present in the effluent stream from the methanol synthesis converter is condensed by cooling and separated from the process stream. The resulting crude methanol is fed through a pipeline 23 to the methanol distillation equipment 9, thus constituting a portion of the refined product methanol.

The process stream leaving the methanol synthesis equipment 22 is preheated to a temperature of the order of 3000C and then fed to a methanator 24 where, under the influence of a nickel catalyst, the very small amounts of carbon monoxide and carbon dioxide present in the process stream are reacted with hydrogen and thereby converted into methane.

The hot process stream leaving the methanator 24 flows into waste heat recovery equipment 25 where the waste heat recovered therefrom is utilized for preheating of boilerfeedwater. The process stream is further water-cooled to ordinary temperature. The process stream leaving the waste heat recovery equipment 25 flows into ammonia synthesis equipment 26 where it is combined with the stream discharged from the circulator and then cooled by contact with ammonia used as a coolant.

Thus, the ammonia present in the stream circulating within the ammonia synthesis equipment 26 is condensed and separated by means of a first separator provided therewithin. Thereafter, the circulating stream is preheated and introduced into an ammonia synthesis converter where, under the influence of an iron catalyst, ammonia is synthesized at a temperature of 3800 to 5000C and a pressure of 100 to 300 kg/cm2 gauge.

The hot gas stream leaving the ammonia synthesis tube is passed through a boiler or a boiler feedwater preheater to recover waste heat therefrom, and finally water-cooled to ordinary temperature.

The ammonia present in the hot gas stream is condensed during this cooling, separated by means of a second separator provided within the ammonia synthesis equipment 26, and withdrawn through a pipeline 27 to obtain product ammonia.

Referring now to Fig. 2, there is illustrated another embodiment of the invention in which the procedure for the removal of carbon oxides comprises low temperature shift conversion, carbon dioxide removal and methanation. In the embodiment of Fig. 2, the steps ranging from the desulfurization of a gaseous hydrocarbon feed or natural gas to the waste heat recovery of the gas resulting from the high temperature shift conversion step are the same as those described in connection with the embodiment of Fig. 1. Accordingly, no detailed description of these steps is given here.

The process stream leaving the waste heat recovery equipment 1 9 is introduced into a low temperature shift converter 28 where most of the residual carbon monoxide is converted into hydrogen and carbon dioxide by contacting the process stream with a conventional copper catalyst at a temperature of 2000 to 2700C.

The process stream leaving the low temperature shift converter 28 is introduced into waste heat recovery equipment 29 where the waste heat recovered therefrom is utilized for the regeneration of carbon dioxide removal equipment 20, the preheating of boiler feedwater, and the like.

After being cooled in the waste heat recovery equipment 29, the process stream is then introduced into carbon dioxide removal equipment 20 where carbon dioxide is removed in the same manner as described previously.

After the removal of carbon dioxide, the process stream is preheated to a temperature of the order of 3000C and introduced into a methanator 24 where the carbon oxides remaining are converted into methane by reacting them with hydrogen under the influence of a nickel catalyst suitable for methanation.

The process stream leaving the methanator 24 enters waste heat recovery equipment 30 where the waste heat recovered therefrom is utilized for the preheating of boiler feedwater, and the like.

Thereafter, the process stream is water-cooled to ordinary temperature.

The process stream leaving the waste heat recovery equipment 30 is compressed to a desired ammonia synthesis pressure by means of a compressor 21 and then subjected to ammonia synthesis in the same manner as described previously.

The above-described integrated process for the production of methanol and ammonia has several advantages as outlined below.

1) Since no nitrogen is admitted to the methanol synthesis process, the need to increase the capacities inter alia of the compressors, methanol synthesis converter can be avoided.

2) Since an ammonia synthesis gas is obtained by reforming the purge gas derived from the methanol synthesis process, the methanol to ammonia production ratio can be controlled at will, especially by introducing an additional hydrocarbon feed into the purge gas reforming step.

3) Since separate reformers are used for the production of a methanol synthesis gas and an ammonia synthesis gas, the reforming process can be carried out under pressure and temperature conditions suitable for the respective gases.

4) Where methanol synthesis is employed for the removal of carbon monoxide and carbon dioxide in the ammonia synthesis process, the production rate of ammonia is reduced. As a result, the feed rate of air used for secondary reforming and hence the power consumption of the air compressor and the like is decreased. Moreover, the decreased feed rate of air used for secondary reforming causes a drop in flame temperature and therefore, the selection of a proper catalyst is facilitated from the viewpoint of thermal resistance.

5) Where methanol synthesis is employed for the removal of carbon monoxide and carbon dioxide in the ammonia synthesis gas stream, the amount of carbon dioxide leaking from the carbon dioxide removal step may be as high as 2 to 3 mole % rather than 0.01 to 0.1 mole % as has been required in the prior art. Thus, the carbon dioxide removal step can be designed and operated with greater ease.

6) Where methanol synethesis is employed for the removal of carbon monoxide and carbon dioxide in the ammonia synthesis process, the low temperature shift conversion step which requires much care in respect of catalyst and operation can be omitted. Thus results in enhanced operability.

7) Where methanol synthesis is employed for the removal of carbon monoxide and carbon dioxide in the ammonia synthesis process, methanation is carried out at high pressure, so that this reaction proceeds benificially from the viewpoint of chemical equilibrium. Thus, a smaller amount of catalyst may be used as compared with the prior art process employing a pressure of the order of 25 kg/cm2 gauge.

The present invention is further illustrated by the followig example.

EXAMPLE According to the embodiment of the invention illustrated in Fig. 1, methanol and ammonia were produced with the material balance given below.

In this example, the consumption of natural gas used as the gaseous hydrocarbon feed amounted to 11.6 x 1 08 Nm3,/year (LHV; 8,652 kcal/Nm3). This represents a reduction of 8% as compared with the total consumption of natural gas (i.e. 12.5 x 108 Nm3/year) required in the conventional separate production of equal amounts of methanol and ammonia. In addition, the present invention allowed the omission of the compressor for natural gas fed to the ammonia production process, the usability of utilities, in common, a decrease in plot area, and other beneficial effects as described previously.

Material Balance (1) Methanol Synthesis Process

Gas entering Natural Hydrogenated methanol vol. gas and desul- Process synthesis Crude Purge feed furized gas steam equipment methanol gas CH4 88.00 5.12 - 5.12 - 17.43 C2H6 4.80 - - - - C3H6 1.46 C4H10 0.25 - - - CO2 0.55 7.37 - 7.37 - 1.57 N2 4.93 1.30 - 1.30 - 4.53 H2 - 71.32 - 71.32 75.13 CO - 14.89 - 14.89 - 1.02 CH3OH - - - - 100.0 0.32 Dry gas 91,693 6,916 - 353,852 73,980 98,795 (Nm /hr) H2O - 35 251,846 311 24,006 28 (Nm /hr) (2) Ammonia Synthesis Process

Gas Purge leaving Gas Gas gas from Gas Gas high leaving leaving Gas methanol leaving leaving temperature CO2 methanol By- leaving synthesis Process primary Process secondary schift removal synthesis product metha- Product Purge process steam reformer air reformer converter equipment equipment methanol nator ammonia gas CH4 17.43 - 9.38 - 0.82 0.77 0.83 0.97 - 1.14 - 15.76 H2 75.13 - 79.42 - 66.94 68.80 73.58 74.09 - 73.94 - 58.70 N2 4.53 - 3.75 - 20.62 19.46 20.81 24.50 - 24.55 - 19.54 CO 1.02 - 4.86 - 8.50 2.39 0.23 0.09 - - - CO2 1.57 - 2.59 - 2.89 8.36 2.00 0.08 - - - CH3OH 0.32 - - - - - - - 100.0 - - Ar - - - - 0.23 0.22 0.23 0.27 - 0.27 - 3.83 NH3 - - - - - - - - - - 100.0 2.17 Dry gas 98,759 - 119,335 37,736 164,453 174,264 162,951 137,819 7,140 137,005 63,524 9,610 (Nm /hr) H2O 28 69,297 58,746 - 65,797 55,986 372 19 3,208 361 - (Nm /hr)

Claims

1. An integrated process for the production of methanol and ammonia which comprises the steps of (a) subjecting a gaseous hydrocarbon feed to primary reforming with steam in the presence of a hydrocarbon reforming catalyst to produce a methanol synthesis gas containing hydrogen and carbon monoxide; (b) subjecting the methanol synthesis gas to methanol synthesis and then separating from the resulting methanol a purge gas containing hydrogen, carbon monoxide, carbon dioxide and methane; (c) subjecting the purge gas to secondary reforming with steam and an oxygen-containing gas to produce an ammonia synthesis gas containing hydrogen, carbon monoxide, carbon dioxide and nitrogen; (d) subjecting the ammonia synthesis gas to high temperature shift conversion and thereby converting the carbon monoxide to carbon dioxide;; (e) passing the resulting carbon monoxide-impoverished ammonia synthesis gas through a series of steps required for the removal of carbon oxides; and (f) subjecting the resulting ammonia synthesis gas to ammonia synthesis.

2. An integrated process as claimed in claim 1; wherein the gaseous hydrocarbon feed comprises one or more hydrocarbons containing 1 to 4 carbon atoms.

3. An integrated process as claimed in claim 1 or claim 2, wherein the primary reforming is carried out at a pressure of 1 5 kg/cm2 gauge and a temperature of 8000 to 9000C.

4. An integrated process as claimed in claim 1,2 or 3 wherein the methanol synthesis is carried out at a pressure of 40 to 100 kg/cm2 gauge and a temperature of 2400 to 2700 C.

5. An integrated process as claimed in claim 1, 2, 3 or 4, wherein the purge gas contains 70 to 80 mole % of hydrogen, 10 to 20 mole % of methane, 1 to 2 mole % of carbon monoxide, and 1 to 2 mole % of carbon dioxide.

6. An integrated process as claimed in any of claims 1 to 5 wherein the oxygen-containing gas is air.

7. An integrated process as claimed in any of claims 1 to 6, wherein prior to the secondary reforming, the purge gas is subjected to additional primary reforming with steam.

8. An integrated process as claimed in claim 7, wherein a make-up hydrocarbon feed is added to the purge gas.

9. An integrated process as claimed in any of claims 1 to 8, wherein the steps employed for the removal of oxides of carbon comprises low temperature shift conversion, carbon dioxide removal and methanation.

1 0. An integrated process as claimed in any of claims 1 to 8 wherein the steps employed for the removal of oxides of carbon comprises carbon dioxide removal, methanol synthesis and methanation.

11. An integrated process as claimed in claim 10, wherein the said methanol synthesis involved in the removal of oxides of carbon is carried out at a pressure of 100 to 300 kg/cm2 gauge and a temperature of 210 to 2700C.

1-2. An integrated process as claimed in any of claims 1 to 11, wherein the ammonia synthesis is carried out at a pressure of 100 to 300 kg/cm2 gauge and a temperature of 3800 to 5000 C.

1 3. An integrated process for the production of methanol and ammonia in accordance with the Example herein.

14. An integrated process for the production of methanol and ammonia, substantially as herein described with reference to Fig. 1 or Fig. 2 of the accompanying drawings.