Ammonia KAAP process

In 2002 the Haber process was the most commercially attractive ammonia process even though it had high compression costs, and a large expenditure of energy was required to produce the feed hydrogen. Improvements such as the AMV process and the KAAP process may provide attractive cost reduction opportunities in ammonia production. 

It should be noted that the KAAP process uses a ruthenium catalyst rather than an iron-based catalyst. The advantages of this catalyst and the KAAP process are discussed below57. In 2001 it was reported that Project and Development India Ltd. (PDIL) had a research program in place to produce ammonia at low temperature (100°C) and low pressure (20 to 40 kg/cm2 g). The catalyst is based on cobalt and ruthenium212. 

The KAAP (Kellogg Advanced Ammonia process) process is the first high-pressure ammonia synthesis process that makes ammonia from nitrogen and hydrogen without the aid of an iron-containing catalyst.1 It is described in References 22-25. 

Figure 113. Kellogg s Ammonia 2000 process (integrated KKES/KAAP process)...

Like iron catalyst, dissociative adsorption of N2 is also the rate determining step on ruthenium catalyst. The difference is that the absorption of H2 strongly inhibits the adsorption of N2, while the inhibition effect for the production of NH3 is not apparent on ruthenium catalyst.The latter is an advantage of ruthenium catalyst, so that the ruthenium catalyst can be placed behind iron catalyst in synthesis ammonia process, e.g., KAAP process.The former effect is still a problem that needs to be solved for the ruthenium catalysts. 

M. W. Kellogg has also suggested a process (the KAAP process) based on a new catalyst [928, 949]. This technology has been used in a revamp project where a new reactor was installed downstream of the existing reactor in an ammonia synthesis loop (see Sect. 6.4.3.4). In addition, more radically new process schemes deviating from the traditional route have been described. An example is a scheme based on so-called parallel reforming [30,32,120,121] and a low pressure loop with ammonia recovery by water absorption [769]. None of these new developments have been implemented in practice. 

Another key feature of this new process is the patented KBR Reforming Exchanger System (KRES), which eliminates the need for the directly fired primary reformer furnace (fig. 6.11). This reduces capital costs by 5-8%, and emissions of NO and CO2 by 70-75%. The first KAAP process was installed for the Ocelot Ammonia Company s (now Pacific Ammonia Inc.) retrofit of its plant in Kitimat, British Columbia, in 1992 and when the first two new KAAP plants (for Farmland Misschem and PCS Nitrogen) were completed at Point Lisas, Trinidad, in July 1998, they became the world s largest ammonia facilities (each at 1,850 t/day) to date. ... 

The design sketched above is an elaborate version of the so-called Kellogg Advanced Ammonia Process (KAAP) in which iron-based catalysts are used in the first bed, and ruthenium-based catalysts, which bind nitrogen more weakly, are used in the second, third and fourth beds [T.A. Czuppon, S.A. Knez, R.W. Schneider and G. Woroberts, Ammonia Plant Safety Relat. Pacil. 34 (1994) 236]. 

Alkali-promoted Ru-based catalysts are expected to become the second generation NHs synthesis catalysts [1]. In 1992 the 600 ton/day Ocelot Ammonia Plant started to produce NH3 with promoted Ru catalysts supported on carbon based on the Kellogg Advanced Ammonia Process (KAAP) [2]. The Ru-based catalysts permit milder operating conditions compared with the magnetite-based systems, such as low synthesis pressure (70 -105 bars compared with 150 - 300 bars) and lower synthesis temperatures, while maintaining higher conversion than a conventional system [3]. 

KAAP [Kellogg advanced ammonia process] The first high-pressure process developed for synthesizing ammonia from its elements which does not use an iron-containing catalyst. The reformer gas for this process is provided by the KRES process. The catalyst was developed by BP it contains ruthenium supported on carbon. Developed by MW Kellogg Company in 1990 and first installed by the Ocelot Ammonia Company (now Pacific Ammonia) at Kitimat, British Columbia, from 1991 to 1992. Another plant was installed at Ampro Fertilizers in Donaldsonville, LA, in 1996. 

Kellogg Advanced Ammonia Process (KAAP), 19 621 Kelly leaf filter, 11 365 Kelp, 14 360... 

M. W. Kellogg has developed a new technology in the synthesis of ammonia. They employ a ruthenium on graphite as the catalyst on Kellogg Advanced Ammonia Process (KAAP). The process is the first to employ a non-iron based catalyst and was co-developed with British Petroleum Ventures. The KAAP has been commercialized since 1994, and has been used in an increasing number of projects. 

Some of the ammonia process technologies that are available include KAAP/ /m.s , Haldor Topspe, LAC (or Linde Ammonia Concept), LCA (or Leading Concept Ammonia), Ammonia Casale, and Uhde. 

Kellogg Brown Root Advanced Ammonia Process - Plus (KAAP)... 

Description The key steps in the KAAP plus process are reforming using the KBR reforming exchanger system (KRES), cryogenic purification of the synthesis gas and low-pressure ammonia synthesis using KAAP catalyst. 

KAAP plus An improved version of KAAP, announced by Kellog Brown Root in 1999. It combines the features of the KBR Advanced Ammonia Process, the KBR Reforming Exchanger System, and the KBR Purifier technology. The catalyst is the same as that used in KAAP. In 2003, more than 200 large-scale plants were operating or had been contracted. 

After C02 removal, final purification includes methanation (8) gas diying (9) and ciyogenic purification (10). The resulting pure synthesis gas is compressed in a single-case compressor and mixed with a recycle stream (11). The gas mixture is passed to the ammonia converter (12), which is based on the Kellogg Brown Root Advanced Ammonia Process (KAAP). It uses a precious metal-based, high-activity ammonia synthesis catalyst to allow for high conversion at the relatively low pressure of 90 bar. 

Figure 95. Kellogg advanced ammonia process (KAAP) a) Compressor b) PGRU c) Refrigeralion...

Kellogg has developed for its ruthenium catalyst based KAAP ammonia process [404], [478] a special converter design. Four radial flow beds are accommodated in a single pressure shell with intermediate heat exchangers after the first, second and third bed. The first bed is loaded with conventional iron catalyst, the following ones with the new ruthenium catalyst. Figure 95 is a simplified sketch of the converter and the synthesis loop of the KAAP for a new plant. For revamps Kellogg has also proposed a two-bed version completely loaded with ruthenium catalyst to be placed downstream of a conventional converter [398]. 

Alternatively, KBR offer the KAAP (Kellogg Advanced Ammonia Process) synthesis concept, where the synthesis gas is converted to ammonia in a low pressure synthesis loop (8-9 MPa) featuring a four bed synthesis converter loaded with conventional iron based catalyst in the first bed and Ru-based catalyst in the lower beds. This technology has so far only had limited use due to the high cost of Ru. 

Since ruthenium catalyst is expensive, highly active and readily inhibited by H2, the process for the ammonia synthesis must be modified to fit these features. In 1980, BP and Kellogg Corporation cooperated to develop a novel ammonia synthesis system, in which BP was to develop a new ammonia synthesis catalyst with high activity at low temperatures and low pressures, while Kellogg was responsible for the development of the matching technology for the process of ammonia synthesis. After a joint effort for 10 years, a process called Kellogg Advanced Ammonia Process (KAAP) was developed successfully (Fig. 1.26). 

Pig. 9.12 Flow-sheet for KBR advanced ammonia process 1-Air compressor 2,12,28,33,34-Cooling 3-Feed gas compressor 4-Waste heat boiler 5-Primary reformer 6-Secondary reformer 7,9,11,15,20,22,26,27,30-Heat recovery 8-HTS 10-LTS 16-Condensate stripper 17-C02 absorber 18-C02 stripper 21-Methanator 24-Dryer 25-Synthesis gas compressor 29-KAAP ammonia converter 32-Refrigeration compressor. 

As an exception that proves the rule, the KAAP (KBR Advanced Ammonia Process) ruthenium-on-carbon catalyst was introduced to commercial application with a Canadian plant retrofit in 1992. The manufacturer claims that the activity of the catalyst exceeds that of magnetite-based materials by about an order of magnitude. 

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