Reformer bayonet

In the ICI gas-heated reformer (GHR) (Figure 49) the reformer tubes consist of an outer scabbard tube with an open ended bayonet tube inside, and the annular space between the tubes is filled with the reforming catalyst. The steam/natural gas mixture enters the tubes via a double tube sheet and flows downwards through the catalyst, and the reformed gas leaves through the bayonet tubes. To enhance the heat transfer from... 

After the secondary reformer of steam reforming plants the gas has to be brought down from around 1000 °C to about 350 °C for the HT shift. In earlier-generation plants two boilers were usually installed in series, with a bypass around the second to control the inlet temperature for the HTS. Common practice for a long time was to use a water-tube design. A famous example is the Kellogg bayonet-tube boiler, applied in more than 100 plants. Because of size limitations two parallel units were installed. For sufficient natural water circulation these boilers needed a steam drum at a rather high elevation and a considerable number of downcomers (feed water) and risers (steam/water mixture). 

TTie bayonet type of reformer tube is adopted to utilize the outlet process gas at the outlet of catalyst layer at the temperature of approximately 830 C. 

The GHR reactor consists of a number of catalyst-filled tubes each with a central bayonet tube. The annular space between these concentric tubes is filled with catalyst. The feed gas (natural gas and steam) enters the top of the reactor vessel and flows through the catalyst-filled annular space and then back through the central tube, giving offbeat to the incoming feed gas. The gas then passes on to the ATR or secondary reformer. The outside surface of the outer tube has an... 

The HTCR reactor consists of a number of bayonet reformer tubes and combines basically the radiant section and the convection section of a conventional HSR in a single piece of equipment. The reaction heat is provided by the flue gas fiowing on the outside of the reformer tubes and by reformed gas fiowing in an upward direction in the bayonet tubes. This results that is about 80% of the fired duty is utilized in the process, and steam export is minimized. 

Convective reforming can also improve the productivity of the fired reformer by utilising the hot product gas for supplementary heat input to the process, i.e. by chemical recuperation of the heat in the process gas instead of raising steam [426] [427]. This can be done in various ways. In the Topsoe Bayonet Reformer (TBR) the product gas may simply be passed through the reformer tube in a bayonet t5 e arrangement, i.e. counter-current to the flow through the catalyst bed. In this way, the capacity of the reformer furnace can be increased by 25% and the steam export reduced by 30% [426]. 

The reformer in Figure 3.10 is applied in a hydrogen plant where the flue gas has an adiabatic inlet temperature close to 1200°C. It is cooled by counter-current heat transfer with the catalyst bed in a system where the flue gas in the bottom is added gradually. The product gas is cooled in a bayonet tube. 

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