A PROCESS FOR START-UP OF THE HYDRODESULFURIZATION SECTION

Abstract

In a process for the start-up of a hydrodesulfurization section, comprising the steps of providing a natural gas feed, passing the natural gas feed through the waste heat section of a reformer, thereby heating the natural gas feed, and passing the heated natural gas feed through a hydrodesulfurization section, thereby heating the hydrodesulfurization section while producing a desulfurized natural gas stream, a part of the desulfurized natural gas stream is provided as fuel for the reformer, while the remainder of the desulfurized natural gas is recycled to at least one point upstream the waste heat section.

Claims

1. A process for the start-up of a hydrodesulfurization section, comprising the steps of: providing a natural gas feed, passing the natural gas feed through the waste heat section of a reformer, thereby heating the natural gas feed, passing the heated natural gas feed through a hydrodesulfurization section, thereby heating the hydrodesulfurization section while producing a desulfurized natural gas stream, and providing a part of the desulfurized natural gas stream as fuel for the reformer and recycling the remainder of the desulfurized natural gas to at least one point upstream the waste heat section.

2. Process according to claim 1, wherein the flow of fresh natural gas feed ensures a sulfur average content above 0.05 ppm at the inlet to the hydrogenator.

3. Process according to claim 1, wherein the start-up process is continued until the temperature of the desulfurized natural gas that is leaving the desulfurizing section, which is the temperature of the hydrodesulfurization section, is between 300 and 400° C., whereupon the remainder of the desulfurized natural gas is provided as feed for the reformer, and the reforming section is started.

4. Process according to claim 2, wherein the start-up process is continued until the temperature of the desulfurized natural gas that is leaving the desulfurizing section, which is the temperature of the hydrodesulfurization section, is between 300 and 400° C., whereupon the remainder of the desulfurized natural gas is provided as feed for the reformer, and the reforming section is started.

Description

[0020] In preferred embodiments, the start-up process is continued until the temperature of the desulfurized natural gas that is leaving the desulfurizing section (i.e. the temperature of the hydrodesulfurization section) is between 300 and 400° C., typically 360° C., whereupon the remainder of the desulfurized natural gas is provided as feed for the re-former, and the reforming section is started.

[0021] The present process for start-up of a hydrodesulfurization section may be used in any plant or in connection with any technology, in which a hydrodesulfurization section is succeeded by a natural gas fired reformer or heater, such as an ammonia, methanol, hydrogen, syngas or ATR plant or process.

[0022] Exemplary values for natural gas (NG) flow, sulfur (S) content and temperature of streams in the heating loop are provided in Table 1 below. As can be seen from the numbers, the natural gas leaving the loop as reformer fuel (4) is replenished by fresh natural gas feed (1).

TABLE-US-00001 TABLE 1 2 5 1 NG feed 3 4 desulfurized NG NG feed plus recycle Recycle Fuel to reformer NG flow, 1500 30000 28500 1500 0 Nm.sup.3/h S content, 20 1 0 0 0 ppm Temper- 40 50 300 100 — ature, ° C.

[0023] When the flue gas from the reformer has a very low content of sulfur (ideally contains no sulfur at all), then it is possible to operate the reformer with a lower reformer flue gas exit temperature. This means that NG consumption as well as CO.sub.2 emission can be reduced.

[0024] Among the main differences from what was previously known is the fact that a part of the desulfurized recycle NG stream is used as fuel for the reformer. This way it is made sure that sulfur-containing NG is constantly sent to the hydrogenator, whereby the catalyst is kept active and ready for use all the time.