Heat-exchange reforming

In some designs the tubes may be open at the lower end, in which case the gas flow on the shell side consists of a mixture of the exit gases from the secondary reformer and from the reformer tubes. Commercially operating designs are the GHR of 1CI [404], [471]-[474] and the KRES of M. W. Kellogg [398], [475]-[479]. 

Similar concepts are available from other licensors and contractors. Braun Root, is offering the Tandem Reformer [480]-[483] a process developed and commercially 

---

Petrochemical Heat Exchangers Reformer tubing Water and Gas supply piping Pipelines... 

Heat exchange autothermal reforming, with a process gas heated steam reformer (heat exchange reformer) and a separate secondary reformer, or in a combined autothermal reformer, using excess or enriched air (under-stoichiometric or stoichiometric H/N ratio)... 

Description Syngas preparation section. The feedstock is first preheated and sulfur compounds are removed in a desulfurizer (1). Steam is added, and the feedstock-steam mixture is preheated again. A part of the feed is reformed adiabatically in pre-reformer (2). The half of feedstock-steam mixture is distributed into catalyst tubes of the steam reformer (3) and the rest is sent to TEC s proprietary heat exchanger reformer, "TAF-X" (4), installed in parallel with (3) as the primary reforming. The heat required for TAF-X is supplied by the effluent stream of secondary reformer (5). Depending on plant capacity, the TAF-X (4) and/or the secondary reformer (5) can be eliminated. 

Synetix Methanol (LCM) Natural gas, refinery offgas Heat-exchange reforming and low-pressure loop technology give high efficiencies 1 1996... 

Another type of steam-reforming reactor that is attracting increasing attention is known as gas heated reformers or heat exchange reformers. In such reformers, heat is transferred by convection and the heat source is a hot process gas from another reformer or a partial oxidation reactor. A number of different installations of heat exchange reformers can be envisaged. In Fig. 5, the installation of a heat exchange reformer either in series or in parallel to an auto-thermal reformer (ATR) is illustrated. 

Fig. 5 Series and parallel arrangement of heat exchange reformers with ATR as the main reformer. (From Ref.. ) this...

In heat exchange reformers, special precautions must be taken to avoid corrosion. In such reformers the metal temperature is often high enough for metal dusting to occur and low enough for thermodynamic potential to exist. Special alloys or other techniques are needed to prevent metal dusting in these cases. This area is the subject of considerable research to widen the limits of operation to more severe operating conditions. 

Substitution of the Primary Reformer by Heat Exchanger Reformer... 

Finally, progress in the heat-exchanger reforming (LCA) process and new developments in electrically driven compressors may make small-scale (300 tpd-400 tpd) installations economically feasible. 

Miyasugi, T., et al. 1984. Energy-Sa mg Ammonia Process with Heat Exchanger Reformer, Am-... 

Fig. 26. Schematic representation of CLR(s) concept. (1) Air reactor/riser, (2) Cyclone, (3) Fuel reactor, (4) fluidized bed heat exchanger/reformer, (5) Shift Reactor, (6) CO2 separation. Courtesy Chalmers University of Technology, Sweden.

The tubular constraint (the last equation) can be made less restrictive by convective heat exchange reformers. This may involve the use of... 

Convective reformers result in less waste heat. The flue gas as well as the product gas is cooled by heat exchange with the process gas flowing through the catalyst beds, so that they leave the reformer at about 600°C. The amount of waste heat is reduced from 50% in the conventional design to about 20% of the fired duty in the heat exchange reformer. This means that the steam generated from the remaining waste heat just matches the steam needed for the process, so that export of steam can be eliminated. 

Chemical recuperation of high-temperature heat is an alternative to raising steam [427]. In ammonia plants the steam is used to drive the S5mgas compressor (refer to Section 2.5), but as discussed for hydrogen plants (refer to Section 2.2) and GTL plants at remote locations (refer to Section 2.6.5) there may be no need for the steam, and recuperation of the heat of the hot process gas in a heat exchange reformer may be an option (as illustrated in Figure 2.35 and Figure 2.36). 

An example of a larger scale fixed-bed reactor is the heat-exchange reformer developed by Haldor Topsoe [476]. It was used for fuel cell applications in the power range of from 50 to 250kW. As shown in Figure 7.1, it is composed of a central homogeneous burner for natural gas fuel and anode off-gas and two annular... 

Figure 9.37 Design concepts of IdaTech steam reformers left, tubular fixed bed steam reformer reactors are placed around a central burner right, heat-exchange reformer the pre-reformer is placed in the outer area ofthe device while the reformer is more in the centre the combustion gases ofthe homogeneous burner pass through several annular gaps between the annular catalyst beds for heating [105].

Patel, K.S. and Sunol, A.K. (2006) Dynamic behaviour of methane heat exchange reformer for residential fuel cell power generation systems. J. Power Sources, 161, 503-512. 

Figure 8.7 Haldor-Topsoe heat exchange reformer.

Figure 5. Heat Exchange Reformer. The Topsoe HER Design.

In the heat exchange reforming case with heat exchange between the catalyst bed and a fluid with temperature T either on the outside at r = R or with an internal tube at r = Rj, the boundary condition can be written as ... 

Process and in Process with Heat Exchange Reforming. All figures per t NHj. (Dybkjaer, 1990). 

---