Temperature cooling-water

If the vapor stream consists of a mixture of unconverted feed material, products, and byproducts, then some separation of the vapor may be needed. The vapor from the phase split is difficult to condense if the feed has been cooled to cooling water temperature. If separation of the vapor is needed, one of the following methods can be used ... 

Separate all noncondensables before feeding to WEE or SPE unit (even a small amount of noncondensables overloads vacuum system, especially at ultrahigh vacuum ranges) most low molecular weight compounds do not condense at cooling water temperatures under high vacuum. 

FIG. 8-36 Block diagram of the cascade co composition disturbance, while L2 would be a change in the cooling water temperature. 

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. 

In selecting the boiling temperature, consideration must be given to the effect of temperature on heat-transfer characteristics of the type of evaporator to be used. Some evaporators show a marked drop in coefficient at low temperature—more than enough to offset any gain in available temperature difference. The condenser cooling-water temperature and cost must also be considered. 

TABLE 12-4 Degree Adjustment to Be Applied to Leaving-Air Wet-Bulb Temperature to Find Cooled-Water Temperatures of Spray Ponds ... 

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. 

The factor a varies considerably with individual alloys and is also dependent on the application conditions. It varies between wide limits from about 0.98 for zinc to below 0.5 for magnesium anodes. The a values given in Tables 6-1 to 6-4 apply to cold seawater. Deviations in application (i.e., cooling water) temperature and loading can lead to considerable changes. 

Difference is defined as inlet gas temperature minus inlet cooling water temperature. Soiirt, [I] Reprinted by permission of the American Society of Mechanical Engineer ... 

Compared with the open system, the average cooling water temperature drop is small, only in the 6-8 "C range. 

To select correct size tails tower and cooler absorber, to meet your specific requirements, follow the dotted line in the two charts. For example, using a 75% concentration of feed gas, 90 cooling water, and absorbing 2,000 Ibs./hr. HCI,- a 92 tube cooler absorber would be required in con unction with a 24" diameter tower. To produce acid over 20 Be to 22 Be, use 12-foot long tubes in ail instances where cooling water temperature falls to left of black dotted line in cooler absorber selection chart. Use 9-foot long tubes where temperature point is to the right of the dotted line. 

The cooling water temperature rise in each zone is... 

Establish condensing temperature of vapors, either by the conditions of other parts of the process (distillation column, vacuum jet, etc.) or by the temperature approach to cooling water, remembering that a close approach will require relatively large surface area. Select the cooling water temperature to ensure performance in the summer months and consider the conditions during the winter (see step 8q). 

Because the cooling water temperature is low enough to allow good cooling, cool the gas to 95 °F. This will be the suction temperature to the second-stage cylinder. 

One of the most important factors is the intercooler cooling water, which has a profound effect on air manifold temperature. Use of a closed-cycle air-cooling system will increase the cooling water temperature with de-rating of output. In addition, the radiators can add significantly to the parasitic load. The altitude above sea level at which the engine will be located also affects the output due to... 

Lubricating oil pressures and temperatures Starting and change air pressures Cooling-water temperatures Exhaust temperature... 

The problem with a conventional system that relies on heat exchangers (i.e. aftercoolers) for moisture removal is temperature. The aftercooler will remove only liquids that have condensed at a temperature between the compressed air and cooling water temperature. In most cases, this differential will be about 20 to 50° lower than the compressed air temperature or around 70 to 90°F. As long as the compressed air remains at or above this temperature range, any remaining vapor that it contains will remain in a vapor or gaseous state. However, when the air temperature drops below this range, additional vapor will condense into water. 

Optimal cooling water temperatures and cooling water flows in upper and lower reactor cooling circuits... 

The heat transfer coefficient from the mbber batch to the cooling water can be estimated by dividing the heat flux by the difference between the average rubber temperature and the cooling water temperature, or... 

Data values are this time included in the equations within the DYNAMIC region. This is not really good practice as it removes from the generality of any given program. The feed temperature Tq and base cooling water temperature Tavg are both 530 R. 

This is clearly too high and intercooling will be needed. Assume compressor is divided into two sections, with approximately equal work in each section. Take the intercooler gas outlet temperature as 60°C (which gives a reasonable approach to the normal cooling water temperature of 30°C). 

Tcond — Tcwi condenser temperature (°C) inlet cooling water temperature (°C) outlet cooling water temperature (°C)... 

---