Amonio

Amonio

Application: to produce ammonia from a variety of hydrocarbon feedstocks ranging from natural gas to heavy naphtha using topsees`s lowenergy ammonia technology.

Descrption: Natural gas or another hydrocarbon feedstock is compressed (if required), desulfurized, mixed with steam and the converted into synthesis gas. The reforming section comprises a prereformer (optional, but gives particular benefits when the feedstock is higher hydrocarbons or naphtha), a fired tubular reformer and a secondary reformer, where process air is added. The amount of air is adjusted to obtain an H2/n2 ratio of 3.0 as required by the ammonia synthesis reaction. The tubular stearn reformer is Topsoe`s proprietary side-wall-fired design. After the reforming section, the synthesis gas undergoes high-and low-temperature shift conversion, carbon dioxide removal and methanation.

Synthesis gas is compressed to the synthesis pressure, typically ranging from 140 to 220 kg/cm2g and converters, either the twobed S-200, the there-bed S-300, or the S-250 concept using an S-200 converter followed by a boiler or steam superheater, and a one-bed S-50 converter. Ammonia product is condensed and separated by refrigeration. This process layout is flexible and each ammonia plant will be optimized for the local conditions by adjustment of various process parameters. Topsoe supplies all catalysts used in the catalytic process steps for ammonia production.

Features, such as the inclusion of a prereformer, installation of a ring-type burner with nozzles for the secondary reformer and upgrading to an S-300 ammonia converter, are all features that can be applied for existing ammonia plants. These features will ease maintenance and improve plant efficiency.

Commercial plants: More than 60 plants use the Topsoe process concept. Since 1990, 50% of the new ammonia production capacity has been based on the topsoe technology. Capacities of the plants constructed within the last decade range from 650 mtpd up to 2.050 mtpd being the world`s largest ammonia plant. Designs of new plants with even higher capacities are available.

Licensor: Haldor Topsoe A/S

Ammonia, KAAP plus

Application: To produce ammonia from hydrocarbon feedstock’s using a high-pressure heat exchange-based steam reforming process integrated with a low-pressure advanced ammonia synthesis process.

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

Following sulfur removal (1), the feed is mixed with steam, heated and split into two streams. One stream flows to the auto thermal reformer (ATR) (2) and the other to the tube side of the reforming exchanger (3), which operates in parallel with the ATR. Both convert the hydrocarbon ted dint raw synthesis gas using conventional nickel catalyst. In the ATR, feed is partially combusted with excess air to supply the heat needed to reform the remaining hydrocarbon feed. The hot autothermal reformer effluent is fed to the shell side of the KRES reforming exchanger, where it combines with the reformed gas exiting the catalyst-packed tubes. The combined stream flows across the shell side of the reforming exchanger where it supplies heat to the reforming exchanger is cooled in a waste heat boiler, where high-pressure steam is generated, and the flows to the CO shift converters containing two catalyst types: one (4) is a high-temperature catalyst and the other (5) is a low-temperature catalyst. Shift reactor effluent is cooled, condensed water separated (6) and then routed to the gas purification section. CO2 is removed from synthesis gas using a wet CO2 scrubbing system such as hot potassium carbonate or MDEA (methyl diethanolamine) (7)

After CO2 removal, final purification includes methanation (8), gas drying (9), and cryogenic purificacition (10). The resulting pure synthesis gas is compressed in a single-case compressor and mixed with a recycle stream (11). The gas mixture is fed to the KAAP ammonia converter (12), which uses a ruthenium-based, high-activity ammonia synthesis catalyst. It provides high conversion at the relatively low pressure of 90 bar with a small catalyst volume. Effluent vapors are cooled by ammonia refrigeration (13) and unreacted gases are recycled. Anhydrous liquid ammonia is condensed and separted (14) from the effluent.

Energy consumption of KBR`s KAAP plus process is less than 25 MMBtu (LHV)/short-ton. Elimination of the primary reformer combined with low-pressure synthesis provides a capital cost savings of about 10% over conventional processes.

Commercial Plants: Over 200 large-scale, single-train ammonia plants of KBR design are on stream or have been contracted worldwide. The KAAPplus advanced ammonia technology provides a low-cost, low-energy design for ammonia plants, minimizes environmental impact, reduces maintenance and operating requirements and provides enhanced reliability. Two plants use KRES technology and 17 plants use Purifier technology. Four 1850-mtpd grassroots KAAP planst in Trinidad are in full operation.

Licensor: Kellogg Brown & Root, Inc.

Ammonia, KBR Purifier

Application: To produce ammonia from hydrocarbon feedstock’s and air

Description: The key features of the KBR Purifier Process are mild primary reforming, secondary reforming with excess air, cryogenic purification of syngas, and synthesis of ammonia over magnetite catalyst in a horizontal converter.

Desulfurized feed is reacted with steam in the primary reformer (1) with exit temperature at about 700ºC. Primary reformer effluent is reacted with excess air in the secondary reformer (2) with exit at about 900 oC. The air compressor is normally a gas-driven turbine (3). Turbine exhaust is fed to the primary reformer and used as preheated combustion air. An alternative to the above described conventional reforming is to use KBR`s reforming exchanger system (KRES), as described in KBR`S KAAPplus.

Secondary reformer exit gas is cooled by generating high-pressure steam(4). The shift reaction is carried out in two catalytic steps-high temperature (5) and low-temperature shift (6). Carbon dioxide removal (7) uses licensed processes. Following CO2 removal, residual carbon oxides are converted to methane in the methanator (8). Methanator effluent is cooled, and water is separated (9) before the raw gas is dried (10).

Dried synthesis gas flows to the cryogenic purifier (11), where it is cooled by feed/effluents heat exchanger. The waste gas stream is used to regenerate

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