Cooling water increase

The thinner solidified shell increased the heat conduction from the molten steel to the shell surface so that the temperature on the shell siuface rose. Since the temperature and flow rate of cooling water changed little, the temperature gradient between the slab and cooling water increased, which promoted the heat conduction from the slab to the mold. 

Separation of low-molecular-weight materials. Low-molecular-weight materials are distilled at high pressure to increase their condensing temperature and to allow, if possible, the use of cooling water or air cooling in the column condenser. Very low... 

SHELLS is greater than 1 for all streams except steam and cooling water. The contribution of these is now increased to one. Thus... 

The process operates at 1 kPa (10 mbars) and 450 kW of power. When the condenser temperature reaches 580°C, the power is reduced to 350 kW. Cooling water is appHed to the condenser, throughout distillation, by means of sprays. Normally distillation takes 10—12 hours and the end point is signified by an increase in furnace temperature and a decrease in vapor temperature to 500—520°C. At this point the power is turned off and the vacuum pump is shut down. Nitrogen is then bled into the system to prevent oxidation of 2inc. 

Continuous chlorination of a cooling water system often seems most pmdent for microbial slime control. However, it is economically difficult to maintain a continuous free residual in some systems, especially those with process leaks. In some high demand systems it is often impossible to achieve a free residual, and a combined residual must be accepted. In addition, high chlorine feed rates, with or without high residuals, can increase system metal corrosion and tower wood decay. Supplementing with nonoxidizing antimicrobials is preferable to high chlorination rates. 

Sindlady, heating surface area needs are not direcdy proportional to the number of effects used. For some types of evaporator, heat-transfer coefficients decline with temperature difference as effects are added the surface needed in each effect increases. On the other hand, heat-transfer coefficients increase with temperature level. In a single effect, all evaporation takes place at a temperature near that of the heat sink, whereas in a double effect half the evaporation takes place at this temperature and the other half at a higher temperature, thereby improving the mean evaporating temperature. Other factors to be considered are the BPR, which is additive in a multiple-effect evaporator and therefore reduces the net AT available for heat transfer as the number of effects is increased, and the reduced demand for steam and cooling water and hence the capital costs of these auxiUaries as the number of effects is increased. 

The condenser design, surface area, and condenser cooling water quantity should be based on the highest cooling water temperature likely to be encountered, if the inlet cooling water temperature becomes hotter then the design, the primaiy booster (ejector) may cease functioning because of the increase in condenser pressure. 

Cooling water was used to cool hot aluminum. Calcium carbonate spotting had occurred at alkaline pH. After reducing pH, the staining problem disappeared, but corrosion increased substantially. 

Corrosion of industrial alloys in alkaline waters is not as common or as severe as attack associated with acidic conditions. Caustic solutions produce little corrosion on steel, stainless steel, cast iron, nickel, and nickel alloys under most cooling water conditions. Ammonia produces wastage and cracking mainly on copper and copper alloys. Most other alloys are not attacked at cooling water temperatures. This is at least in part explained by inherent alloy corrosion behavior and the interaction of specific ions on the metal surface. Further, many dissolved minerals have normal pH solubility and thus deposit at faster rates when pH increases. Precipitated minerals such as phosphates, carbonates, and silicates, for example, tend to reduce corrosion on many alloys. 

Because alterations to equipment design can be cumbersome and expensive, a more economical approach may be to change the metallurgy of affected components. Metals used in typical cooling water environments vary in their resistance to erosion-corrosion. Listed in approximate order of increasing resistance to erosion-corrosion, these are copper, brass, aluminum brass, cupronickel, steel, low-chromium steel, stainless steel, and titanium. 

Cooling water system corrosion causes immediate and delayed problems. Difficulties spread from a failure like ripples from a pebble thrown into a pool. A single failure may force an unscheduled outage, redirect worker efforts, contaminate product, compromise safety, increase equipment expense, violate pollution regulations, and decrease productivity. 

Cooling water pipes are essential for the operation of power stations and must not cease to function. Pipelines for fire fighting are also important for safety reasons. Such steel pipelines are usually well coated. At areas of unavoidable damage to the pipe coating, there is an increased danger due to cell formation between steel and concrete where local corrosion rates of >1 mm a are to be expected [4], Damage to pipelines for fire fighting has frequently been observed after only a few years in service. 

For areas where cooling water is either scarce or not available, direct liquid injection may be a possibility. The liquid coolant should be injected near the discharge end of the compressor to minimize lubricant dilution. Alternatively, the liquid can be flashed in a separate exchanger and used to cool the lubricant. While the cooling may appear to decrease the power to the compressor, the net effect is an increase in the power due to the additional weight flow of the extra refrigerant needed to perform the cooling. 

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