JPS6086004A - Method of obtaining pure co and pure h2 - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The invention is directed to the use of CO□ produced in a reformer by endothermic catalytic oxidation of optionally desulfurized hydrocarbons in the presence of CO□ as a component supplying oxygen. It relates to a method for obtaining pure CO and pure 11□ from a gas mixture consisting mainly of hydrogen and carbon monoxide.

According to West German Publication No. 2711991, approximately 70% by volume of CO acid component and approximately 30% by volume of H2 component are removed by endothermic catalytic oxidation of hydrocarbons in the presence of CO□ as oxygen supplying agent. Possible content of CO7 and C
Methods are known for obtaining gas mixtures containing H4 at approximately atmospheric pressure. Underfire gas (underfire gas) is supplied to heat the reformer which works by endothermic action.
The waste gas of ng) and the product gas obtained during the oxidation are cooled in separate devices in the above-mentioned method, and the Co2 contained in the gas is washed with an alkaline absorbent, in particular monoethanolamine, and combined. It is released from the absorbed absorbent by thermal desorption and reused during oxidation.

This method is unsatisfactory in terms of waste heat recovery and has been proposed by the applicant in West German Patent No. 1 #JI P 3305299.9, in which the charge is heated before it is introduced into the reformer. is mixed with COz, and the mixture contains 2 to 20
An improvement was proposed in which the catalytic oxidation was carried out at a pressure of 1 bar and a temperature of 900 to 1100'C. In particular, at this time, the charge material is also desulfurized before it is introduced into the reformer.

Furthermore, the present invention aims to provide a method for obtaining pure CO and pure Ti2 from reformed gas generated by catalytic oxidation in a known manner with reduced investment costs and energy consumption. do.

Light quantity! The above-mentioned object is solved according to the features of the invention by obtaining fractions of pure CO□, pure CO and pure H2 from the reformed gas by adsorption.

C in the present invention is based on the recognition that significant energy savings can be made when CO2 from an external source is present if only the reformed gas is purified or decomposed. For this purpose, adsorption is proposed to be particularly advantageous.

This allows the reformate gas to be removed in a manner known per se, without generating waste streams or incurring high costs for cleaning agent regeneration, pumps and other auxiliary equipment, as in the case of amine cleaning. can be separated into product streams of C01H2 and CO2. In this case, the process according to the invention makes it possible to obtain a CO product with a purity of more than 95%, in particular more than 98%, while at the same time obtaining a H2 product with a purity of more than 98%.

However, CO□ is not always available from external sources. In such a case, the present invention proposes to separate CO2 from the flue gas generated when heating the reformer by adsorption and return it to the reformer together with the CO□ separated from the reformed gas. It will be done. However, in this process, external CO2 can be used additionally as a charge if necessary. Such a process with adsorption purification of the flue gas results in pure N2 under pressure, which is simultaneously discharged as product. In particular, the flue gas always has a certain residual oxygen content, usually more than 0.5% by volume. To remove this oxygen, it is proposed according to the invention that the flue gas be subjected to an alkaline reduction of the oxygen content before the CO2 separation. This is particularly useful when pure N2 is required in dry form. Therefore, 02 removal is performed before CO□ adsorption to save energy for drying.

If nitrogen may be present in wet form, catalytic reduction of t-containing oxygen can be carried out on a CO,-free flue gas. This first removes CO□ from the flue gas and then hydrogenates the oxygen content. For this reason, the substantially H
A purge gas consisting of 2 is utilized. This purge gas can also be utilized as a hydrogen feed agent in the catalytic reduction of oxygen prior to the separation of CO□ from the flue gas.

The pressure exchange method has proven to be particularly suitable for operating the adsorption device and makes it possible to save energy.

BRIEF DESCRIPTION OF THE DRAWINGS In the following, the method according to the invention will be explained in more detail by means of an embodiment illustrated schematically in two drawings.

Now, in FIG. 1, sulfur-containing reformable hydrocarbons are introduced into a desulfurization unit 2 via a conduit 1 and are partially desulfurized in a desulfurization unit N2. The desulphurized effluent discharged into conduit 3 is mixed with CO2 supplied into conduit 3 from an external source via conduit 4, and enriched with COt, which will be explained in more detail below. Solder purge gas is mixed via conduit 5 and this gas mixture is introduced into reformer 6. A heating medium is further introduced into the reformer 6 via a conduit 7, and a purge gas rich in COt is introduced via a conduit 20.

In the reformer 6 a pressure of 2 to 20 bar and 90 bar
The hydrocarbons are converted by catalytic oxidation in the presence of Co as oxygenating agent at temperatures between 0 and 1100 °C. Via conduit 8, mainly C01Hz and CO
The reformed gas consisting of 3 is discharged and introduced into the purification device 9, where it is separated and purified by adsorption. This results in pure CO and pure H2 as well as COt as separated product streams, respectively, by means of a pressure exchange process. The pure CO is discharged as product via conduit 10, the pure H8 is mostly discharged as product via conduit 11, and the remaining portion is introduced via conduit 12 into the catalytic desulfurization unit 2 as hydrogen for hydrogenation. Ru. In the embodiment described above, the CO□-enriched purge gas is not provided as a separated distillate, but rather in conduit 5.
This purge gas is obtained as a purge gas which is discharged through a process, but this purge gas still contains CO and H7 as well as CO8. The flue gas generated in the reformer 6 is transferred to the heat recovery device 1.
After recovering the heat available in 3, it is discharged via conduit 16, and the intermediate pressure steam generated is discharged via conduit 17.

In the embodiment according to FIG. 2, the sulfur-containing reformable hydrocarbon is partially introduced via line 18 into a desulfurization device 19 and is desulfurized therein. The desulfurized reforming charge is introduced into a reformer 23 via a conduit 22. The reforming charge in conduit 22 is mixed with recycled CO0 from conduit 24. The undesulfurized portion of the charge is introduced via conduit 25 into reforming bag af23 as a heating medium. In this 1, the hydrocarbon is heated at a pressure of 2 to 20 bar and 900 to 11 bar in the presence of COz as oxygenator.
Catalytic oxidation is performed at a temperature of 00° C., and the resulting reformed gas is discharged through a conduit 26 and introduced into an adsorption decomposition purification device 27.

Here the reformed gas is separated in a manner known per se by a pressure exchange method, the pure CO obtained being discharged as a distillate stream via line 28 and the pure H2 being partially discharged as a product stream via line 29. However, the remaining portion of pure H2 is introduced via conduit 30 into desulfurization unit 19 as hydrogen for hydrogenation.

The flue gas generated in the reformer 23 and in the flue gas heat recovery device &31, optionally by the underfire stoking device (32, 33), is subjected to a catalytic reduction device 34 for the residual oxygen contained after recovery of the heat. will be introduced in Conduit 3 from adsorption decomposition purification device 21 as hydrogen for hydrogenation for this reduction device 34
A purge gas introduced through step 5 is utilized. The reduced flue gas is introduced into an adsorption device ff136 operating in the pressure exchange method for the separation of CO□ by adsorption. In this case, external flue gas is additionally introduced into the adsorption device 36 via a line 37, in order to sufficiently supplement the requirements for catalytic oxidation. The CO2 separated in this adsorber 36 is mixed as recycled CO2 into the charge to the reformer via conduit 24. Pure N from the CO0 separation adsorption device 36! can be discharged as a product stream via conduit 38. Conduit 3 not needed in catalytic reduction device 34
A portion of the purge gas in 5 is introduced into the reformer 23 via conduit 21 for further separation in the reformer 23 and/or reformed via conduit 39 for additional underfire. It can be introduced into the heat recovery device 23 and/or utilized in the heat recovery device 31 via the conduit 33. This increases the carbon yield of CO production to the reformer charge 18 and the reformer and optionally the feed firing (25, 32, 33) to practically 100x. High pressure steam exits the flue gas heat recovery device 31 via conduit 40 .

As mentioned above, the present invention reduces investment costs, saves energy consumption, and produces pure CO and pure Ht through catalytic oxidation.
This provides an excellent method for efficiently obtaining .

[Brief explanation of the drawing]

FIG. 1 is a circulation circuit diagram showing a purification method by adsorption of reformed gas according to an embodiment of the present invention. FIG. 2 is a circulation circuit diagram showing a method of purifying reformed gas and flue gas by adsorption according to the present invention. 2.19... Desulfurization device 6.23... Reformer 9.27... Purification device 13.31... Heat recovery device 34... ...Catalytic reduction device 36 ...Adsorption device

Claims (5)

[Claims] (1) In the presence of CO2 as a component that supplies oxygen,
In a process for obtaining pure CO and pure H2 from a gas mixture consisting mainly of hydrogen and carbon monoxide generated in a reformer by endothermic catalytic oxidation of optionally desulphurized hydrocarbons, the method comprises: obtaining pure CO and pure H2 from the reformed gas by adsorption; Pure Cq
2. A method for obtaining pure CO and H2 fractions. (2) CO from flue gas generated when heating the reformer
2. The method according to claim 1, further comprising additionally separating CO2 by adsorption and returning this CO2 together with the CO□ separated from the reformed gas to the reformer. (3) Before the separation of 'Co□, the flue gas is subjected to catalytic reduction of the oxygen contained therein using the purge gas generated when the reformed gas is decomposed or the reformed charge. The method of claim 2, characterized in that: (4) Catalytic reduction of the oxygen contained in the CO□-free flue gas is performed using purge gas or reforming charge generated when reformed gas is decomposed. The acquisition method described in Section 2. (5) The method according to any one of claims 1 to 4, characterized in that the adsorption is carried out by a pressure exchange method.