Ammonia refrigeration

The reason for the popularity of anhydrous ammonia is its economy. No further processing is needed and it has a very high (82.2%) nitrogen content. Additionally if held under pressure or refrigerated, ammonia is a Hquid. Being a Hquid, pipeline transport is practical and economical. A network of overland pipelines (Fig. 4) is in operation in the United States to move anhydrous ammonia economically from points of production near natural gas sources to points of utilization in farming areas (see Pipelines). 

The ammonia-water absorption system was extensively used until the fifties when the LiBr-water combination became popular. Figure 11-103 shows a simplified ammonia-water absorption cycle. The refrigerant is ammonia, and the absorbent is dilute aqueous solution of ammonia. Ammonia-water systems differ from water-lithium bromide equipment to accommodate major differences Water (here absorbent) is also volatile, so the regeneration of weak water solution to strong water solution is a fractional distillation. Different refrigerant (ammonia) causes different, much higher pressures about 1100-2100 kPa absolute in condenser. 

Organic fluorine as a separate industry that began in the late 1920s with the discovery by Midgle of fluorocarbons for use as refrigerants. Ammonia was unsuitable because of the hazard and unpleasant smell from minute leaks. Sulfur dioxide had similar problems. The best refrigerant was... 

The following PSA of a refrigerated ammonia storage facility is from Papazoglou (1990a, 1990b). An obje ve of the work was to test PSA as it had been applied to nuclear power... 

With ammonia, oil sinks to the bottom and does not go into solution with the refrigerant. Ammonia condensers, receivers and evaporators can be distinguished by the provision of oil drainage pots and connections at the lowest point. Automatic drainage and return of the oil from these would have to depend on the different densities, and is veryrarely fitted. The removal of oil from collection pots and low-point drains is a periodic manual function and is carried out as part of the routine maintenance. The halocarbons are all sufficiently miscible with oil to preclude the possibility of separate drainage in this way. 

Absorption refrigeration (ammonia to -30°F, lithium bromide to -h45°F) Is economical when waste steam Is available at 12 psig or so. 

Refrigerant - [AMMONIA] (Vol 2) -chloroformuse [CITLOROCARBONSANDCHLOROHYDROCARBONS - CHLOROFORM] (Vol5)... 

Liquid ammonia shipments by barge constitute a larger volume than by road or rail. Barge shipments supply users without then own production and to meet needs caused by operating breakdowns. Refrigerated ammonia is the preferred... 

The results for the warm and pressurized ammonia storage (unmitigated) and the refrigerated ammonia storage (mitigated) are summarized in Table 7.4. 

In this scenario, a dike 8.4 m by 8.4 m having a height of 1.5 m is placed around the refrigerated ammonia storage tank. The accidental failure of the 37.5-mm line occurs inside the diked area. All of the liquid ammonia released from the tank is contained inside the dike. The rate of flow of the liquid ammonia into the dike is the same as for the refrigerated example (Section 7.7.2). 

The purified syngas is compressed in the syngas compressor (12), mixed with the loop-cycle stream and fed to the converter (13). Converter effluent is cooled and then chilled by ammonia refrigeration. Ammonia product is separated (14) from unreacted syngas. Unreacted syngas... 

Carcinogenic potential of ammonia by the inhalation route has not been assessed in humans or animals. One case report was found of a white male who developed epidermal carcinoma of the nasal septum 6 months after being badly burned by accidental contact with a refrigeration ammonia-oil mixture (Shimkin et al. 1954). If ammonia played a role in the development of this cancer, it was most likely due to dermal exposure, not inhalation, since the substance was oily. However, some of the ammonia was probably inhaled into the nasal vestibule and absorbed into nasal mucous. No other such reports were located, although other cases of inhalation exposure to ammonia from spills have been followed for more than 6 months after exposure. One of 10 adult male mice exposed to ammonia gas for 15 minutes/day 6 days/week for 8 weeks had mitotic figures with an intact basement membrane and a carcinoma in situ in one nostril and one mouse had an invasive adenocarcinoma of the nasal mucosa (Gaafar et al. 1992). 

Shimkin MB, de Lorimier AA, Mitchell JR, et al. 1954. Appearance of carcinoma following single exposure to a refrigeration ammonia-oil mixture. Arch Ind Hyg Occup Med 9 186-193. 

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