Weekly Topic: Principles for controlling the temperature of water coolers and what factors affect their performance? 2016.5.23--5.29

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For the methanol section’s weekly topics, we encourage all members to participate actively. The purpose of this activity is to review the knowledge we have already learned; through answering questions, we can improve our knowledge, broaden our understanding, reinforce what we already know, recall what we have forgotten, and deepen discussions on controversial topics, thereby progressing together. We welcome any opinions or suggestions you might have; please feel free to share them so that we can work together to improve this methanol section and create a better platform for communication for everyone! ! There will be a reward for everyone who answers; great content is available upon reply. Weekly Topic: What are the principles for controlling the temperature of water coolers, and what factors affect their performance? May 23–29, 2016 1. What are the disadvantages of excessively high and low gas temperatures after the cooling of syngas? Answer: If the temperature of the gas after water cooling of syngas is controlled too high, it will affect the condensation of methanol and water vapor in the gas. As the water cooling temperature of the syngas increases, the amount of methanol that remains uncondensed in the gas rises; this methanol not only increases the energy consumption of the recycle compressor but also hinders the synthesis of methanol into its desired products within the methanol synthesis tower. However, the water cooling temperature of the syngas does not need to be controlled too low either. As the water cooling temperature decreases, the condensation effect of methanol increases accordingly, but when the temperature drops below 20°C, the increase in methanol’s condensation effect becomes less significant. Therefore, pursuing excessively low water cooling temperatures is uneconomical; it not only requires more sophisticated equipment but also increases the consumption of cooling water. 2. What are the main factors affecting the cooling efficiency of the water cooler in methanol synthesis? Answer: The reduced water cooling effect may be due to the following reasons: ① The amount of water has significantly decreased, which affects its cooling capacity. The cooling water flow rate can be increased by opening the cooling water inlet valve wider and raising the cooling water pressure. ②The buildup of scale and sediment on the wall of the water-cooler tubes worsens, which affects heat transfer and the removal of heat, thereby impacting the cooling efficiency. ③The water quality is relatively poor, and the water may contain impurities such as plastic sheets. These impurities have a significant impact on the cooling efficiency of the water cooler, especially in shell-and-tube heat exchangers. They accumulate on the inlet plates of the cooler, blocking the pores and preventing smooth flow of water, which in turn affects the cooling performance. In such cases, in addition to improving water treatment and purification, two parallel filters can be installed before the water enters the cooler to remove these impurities. ④Paraffin is produced during methanol synthesis, and this paraffin adheres to the inner walls of the condenser tubes; over time, this has an increasing negative impact. If wax accumulation is severe and affects production, steam purging or thermal cooking can be employed to remove it.