Vertical retort process

Until the end of World War II, coal tar was the main source of these aromatic chemicals. However, the enormously increased demands by the rapidly expanding plastics and synthetic-fiber industries have greatly outstripped the potential supply from coal carbonization. This situation was exacerbated by the cessation of the manufacture in Europe of town gas from coal in the eady 1970s, a process carried out preponderantly in the continuous vertical retorts (CVRs), which has led to production from petroleum. Over 90% of the world production of aromatic chemicals in the 1990s is derived from the petrochemical industry, whereas coal tar is chiefly a source of anticorrosion coatings, wood preservatives, feedstocks for carbon-black manufacture, and binders for road surfacings and electrodes. 

Redistillation. For certain appHcations, especially those involving reduction of other metal compounds, better than 99% purity is required. This can be achieved by redistillation. In one method, cmde calcium is placed in the bottom of a large vertical retort made of heat-resistant steel equipped with a water-cooled condenser at the top. The retort is sealed and evacuated to a pressure of less than 6.6 Pa (0.05 mm Hg) while the bottom is heated to 900—925°C. Under these conditions calcium quickly distills to the condensing section leaving behind the bulk of the less volatile impurities. Variations of this method have been used for commercial production. Subsequent processing must take place under exclusion of moisture to avoid oxidation. 

OC-Hemihydrate. Three processing methods are used for the production of a-hemihydrate. One, developed in the 1930s, involves charging lump gypsum rock 1.3—5 cm in size into a vertical retort, sealing it, and applying steam at a pressure of 117 kPa (17 psi) and a temperature of about 123°C (6). After calcination under these conditions for 5—7 h the hot moist rock is quickly dried and pulverized. 

These formerly involved the use of banks of externally heated, horizontal retorts, operated on a batch basis. They were replaced by continuously operated vertical retorts, in some cases electrically heated. Unfortunately none of these processes has the thermal efficiency of a blast furnace process (p. 1072) in which the combustion of the fuel for heating takes place in the same chamber as the reduction of the oxide. The inescapable problem posed by zinc is that the reduction of ZnO by carbon is not spontaneous below the boiling point of Zn (a problem not encountered in the smelting of Fe, Cu or Pb, for instance), and the subsequent cooling to condense the vapour is liable, in the presence of the combustion products, to result in the reoxidation of the metal ... 

Destrugas A process for destroying organic wastes by pyrolysis in an indirectly heated vertical retort. The comminuted waste is fed from the top, and raw gas and coke are withdrawn from the bottom. 

Galoter A process for extracting oil and gas from shale, using a vertical retort. Operated in Estonia since 1964. 

New Jersey A continuous process for extracting zinc from zinc oxide, made by roasting zinc sulfide ore, by reduction with carbon in a vertical retort. First operated by the New Jersey Zinc Company in Palmerton, PA, in 1929, and introduced into the Avonmouth, UK, works of the Imperial Smelting Company in 1934. 

V. Yefimov, and T. Purre, Main Factors Influencing Processing of...Oil Shale in Vertical Retorts, Oil Shale, 13(2), 123-132 (1996). 

Primary distillation of crude tar produces pitch (residue) and several distillate fractions, the amounts and boiling ranges of which are influenced by the nature of the crude tar (which depends upon the coal feedstock) and the processing conditions. For example, in the case of the tar from continuous vertical retorts, the objective is to concentrate the tar acids, (phenol, cresols, and xylenols) into carbolic oil fractions. On the other hand, the objective with coke oven tar is to concentrate the naphthalene and anthracene components into naphthalene oil and anthracene oil, respectively. 

Processing. The cherry samples were canned in standard sized lacquered cans (7.5 cm diameter x 11 cm), filled with deionised water, and sealed. The cans were then heat treated at 121°C for 2.5 min (12 D concept) using a Fraser Vertical Retort with a Taylor MOD 30 Controller. The canned samples were then opened and volatiles extracted using the static vacuum SDE as described above. 

The monolayer cast film and the multilayer cast film were measured and cut to produce prototype pouches for subsequent retort processing the dimensions of the pouches were 19.05 x 6.98 cm. The pouches were filled with distilled water and vacuum sealed to simulate the retortable MRE pouches which are filled with food products and retorted to sterilize the products inside. The retort machine used was the Validator 2000 Vertical Water and Steam Retort, which cooked the pouches for 30 minutes at 121°C. 

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