Synthesis Gas Demonstration Plant Program, Phase I. Trade-off Studies Report V: Cooling Tower Optimization

摘要

The basic results of the economic investigation of rectangular mechanical draft cooling towers for the commercial plant application are tabulated. The results show that the annual costs, adjusted for the influence of cooled water temperature and cooling range on plant equipment costs and performance, follow a well defined pattern. Specifically, we find that for a given design cooled water temperature, costs are reduced when the cooling range (or temperature rise through the plant) is increased. The rate of cost reduction decreases however, indicating an eventual reversal of the trend caused by a rapid increase in the cost of plant equipment designed for high range and high temperatures. It is also noted that costs decrease as the design cooled water temperature approaches the design wet bulb temperature. This trend is due to the influence of plant costs since the trend in cooling tower costs is opposite. An optimum occurs at 83 exp 0 F cooled water temperature due to rapidly increasing cooling tower costs. The plotted results show that for all cooling ranges up to 35 exp 0 F, a cooled water temperature of 83 exp 0 F is the economic choice. This is also the lowest practical choice for cooling tower design. To allow for the specification of plant equipment to accept a cooled water temperature in excess of 83 exp 0 F, and to allow for some deterioration in tower performance without exceeding 120 exp 0 F hot water temperature, it is recommended that a range of 30 exp 0 F be used. Summarizing, it is recommended that the cooling tower be of the conventional rectangular mechanical design and based upon a cooled water temperature of 83 exp 0 F and a cooling range not to exceed 30 exp 0 F. (ERA citation 05:030077)