Oxygenating plants

Specimen Location Heat exchanger aftercooler of an oxygen plant... 

The nitrogen is obtained as a byproduct of an oxygen production process (1,200 tpd of oxygen) in a dedicated oxygen plant. In diis plant, parallel expansion turbines are used dial were designed especially for die process. The first expansion turbine train (two... 

The Kalgoorlie niekel mine is about 6 m south of Kalgoorlie, Australia. It is operated by Western Mining Corporation and fed by a modern oxygen plant. Niekel was first diseovered at nearby Kambalda in 1966. By 1970, eoneentrated niekel sulfide ore was being mined and delivered to the Kwinana refinery near Perth. Then, in 1972, a smelter was built near Kalgoorlie so that produetion at the Kambalda mine eould be inereased. 

In a business where oxygen plants play a key role in the eost of the end produet, Western Mining needs high proeess effieieneies. This prompted the eompany to seleet a eustom-built eentrifugal eompressor and turboexpander. 

Motor-driven reciprocating compressors are sometimes used in tonnage oxygen plants. To maintain a uniform output, the plant must be supplied with a constant weight flow of air. As ambient conditions change weight flow, a control system as shown in Figure 8-40(f) can be used to keep the plant supplied with the proper quantity of air. The necessary steps in this system are ... 

Another way to eliminate the oxygen plant is to react a metal oxide with methane to yield the synthesis gas in a fluidized-bed reactor (83-86). Experiments have shown that copper oxide readily oxidizes methane to carbon monoxide and hydrogen with high selectivity at a temperature of about 1200 K and that the reduced CuO can be reoxidized with air. Lewis et al. (83-86)... 

Net cost of the phenol (cumene + oxygen + plant operating cost less acetone less by-product values) ... 

The pond can be filled with rain or tap water. If using city water, wait at least 48 hours for the chlorine to dissipate before Introducing floating or oxygenating plants. Wildlife will move in rapidly of Its own accord, and within a year your pond should have a full complement of creatures. It Is not uncommon for new ponds to suddenly turn a vivid green. Do not be alarmed this algal bloom will clear by Itself, although you can help It to disperse (seep.l23). 

Flave submerged oxygenating plants occupying around 25-33% of the volume of water. 

Includes overhead, operations, maintenance, oxygen plant staffing. 

However, in contrast to the cyclic flow of electrons in purple bacteria, some electrons flow from the reaction center to an iron-sulfur protein, ferredoxin, which then passes electrons via ferredoxin NAD reductase to NAD+, producing NADH. The electrons taken from the reaction center to reduce NAD+ are replaced by the oxidation of H2S to elemental S, then to SOf, in the reaction that defines the green sulfur bacteria. This oxidation of H2S by bacteria is chemically analogous to the oxidation of H20 by oxygenic plants. 

Designers also face the choice of capacity of an oxygen plant. Costs per unit weight of oxygen made are lowered as the capacity of the plant goes up. For example, a plant with a capacity of 2000 tons (1800 metric tons) per day will produce oxygen at approximately 50% of the cost per nnit weight as a plant with a 200-ton (180-metric ton) capacity per day. 

The HiSmelt process being developed jointly by CRA of Australia and Midrex Direct Reduction Corp. uses a horizontal vessel, relying on turbulence in the bath to spray particles of slag and iron into the atmosphere above the bath, where heat is transferred from the post-combustion flame to the particles. Here, air is used instead of oxygen, thus removing the requirement of an oxygen plant. This technology emphasizes bottom injection of coal and dust into the iron bath. 

And now I would like to comment on how much cost reduction can we really expect from all of this work. Figure 6 shows a breakdown of investment by plant section for a typical Lurgi SNG plant. The information is about three years old from the open literature. As shown, the gasification section accounts for only about 20% of the total plant investment. Other process sections, including shift, methanation, and other process gas account for another 30%, making a total of 50% for the process sections. The utilities add up to 33%, including 11% for the oxygen plant alone. 

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