Process for the production of synthesis gas

Abstract

A process for producing synthesis gas, the process comprising the steps of a) reforming a hydrocarbon feed in a reforming section thereby obtaining a synthesis gas comprising CH4, CO, CO2, H2 and H2O and impurities comprising ammonia; b) shifting the synthesis gas in a shift section comprising one or more shift steps in series to a shifted synthesis gas; c) separating from the shifted synthesis gas a process condensate originating from cooling and optionally washing of the shifted synthesis gas; d) passing a part of the process condensate to a condensate steam stripper, wherein dissolved shift byproducts comprising ammonia, methanol and amines formed during shifting the synthesis gas are stripped out of the process condensate using steam resulting in a stripper steam stream, e) adding the stripper steam stream from the process condensate steam stripper to the hydrocarbon feed and/or to the synthesis gas downstream the reforming section, up-stream the last shift step, wherein the remaining part of the process condensate is purged.

Claims

1. A process for producing synthesis gas, the process comprising: a) reforming a hydrocarbon feed in a reforming section having a pressure inlet to obtain a synthesis gas comprising CH.sub.4, CO, CO.sub.2, H.sub.2 and H.sub.2O and impurities comprising ammonia; b) shifting the synthesis gas in a shift section comprising one or more shift steps in series to obtain a shifted synthesis gas; c) separating, from the shifted synthesis gas, a process condensate originating from cooling and optionally washing of the shifted synthesis gas; d) passing a part of the process condensate to a medium pressure condensate steam stripper, wherein the pressure of the medium pressure condensate steam stripper is higher than the pressure in the pressure inlet, and wherein dissolved shift byproducts comprising ammonia, methanol and amines formed during shifting of the synthesis gas are stripped out of the process condensate using steam to obtain a stripper steam stream; and e) adding the stripper steam stream to the hydrocarbon feed and/or to the synthesis gas downstream of the reforming section and upstream of the last shift step, wherein the remaining part of the process condensate is purged upstream of the medium pressure condensate steam stripper.

2. The process of claim 1, wherein the purge of the remaining part of the process condensate is passed to a purge condensate steam stripper.

3. The process of claim 2, wherein the purge condensate steam stripper is a low pressure purge condensate steam stripper, wherein the pressure of the low pressure purge condensate steam stripper is lower than the pressure of the pressure inlet.

4. The process of claim 2, wherein steam from the purge condensate steam stripper is condensed, and non-condensable gases are employed as fuel.

5. The process of claim 1, wherein stripped condensate from the medium pressure condensate steam stripper is passed to water treatment.

6. The process of claim 2, wherein stripped purge condensate from the purge condensate steam stripper is passed to water treatment.

7. The process of claim 1, wherein the pressure of the medium pressure condensate steam stripper is 0.5 bar higher than the pressure in the pressure inlet.

8. The process of claim 7, wherein the pressure of the medium pressure condensate steam stripper is 1.0 bar higher than the pressure in the pressure inlet.

9. The process of claim 3, wherein the pressure of the low pressure purge condensate steam stripper is from 0.5 bar to 20 bar.

Description

EXAMPLE

(1) Reference is made to FIG. 1

(2) The stream numbers in the tables below refers to the reference numbers in FIG. 1

(3) Table 1 shows a case for removing formed ammonia and amines by converting these in the reforming section by adding 8.4% of the stripped steam to this unit.

(4) Table 2 shows a case for removing formed ammonia and amines by purging 8% of the process condensate.

(5) There is in both cases the same built-up of ammonia and amines in the shift section. This built-up can be reduced or removed by admitting all the stripped steam to either the reforming section or the process condensate purge.

(6) TABLE-US-00001 TABLE 1 Stream 1 2 3 4 5 6 7 8 9 10 11 Flow 92 100 168 255 255 125 0 125 95 87 8 T/h Ammo- 0 40 42 482 480 480 0 480 480 440 40 nia Kg/g Amines 0 3 0 33 36 36 0 36 36 33 3 Kg/h

(7) TABLE-US-00002 TABLE 2 Stream 1 2 3 4 5 6 7 8 9 10 11 Flow 100 100 168 255 255 125 10 115 87 87 0 T/h Ammo- 0 0 42 480 478 478 40 438 438 438 0 nia Kg/g Amines 0 0 0 33 36 36 3 33 33 33 0 Kg/h