Abstract : This paper mainly introduces the selection of equipment upgrade schemes for the high-pressure ammonia pump speed regulation system, the economic benefits of using high-pressure frequency converters to upgrade the high-pressure ammonia pump speed regulation system, the external factors that should be paid attention to in the operation and maintenance of the frequency conversion speed regulation system, and further conducts regression analysis on the P-n relationship. A quantitative relationship between power and speed is established. Keywords : constant torque, high-pressure frequency converter, minimum total cost method, speed regulation, energy saving, regression analysis [b]1 Overview[/b] Luzhou Tianhua's 300,000-ton/year synthetic ammonia and urea plant was introduced from abroad in the 1970s and has been in operation for nearly 30 years. The high-pressure ammonia pump is a plunger pump, which relies on a hydraulic torque converter to control the pump speed to regulate the pump flow. After long-term use and maintenance, the hydraulic torque converter's regulation performance and reliability have gradually decreased, and maintenance costs have increased year by year, requiring replacement to meet the needs of the production process. This paper analyzes the replacement of hydraulic couplings with high-pressure frequency converters in high-pressure ammonia pumps, illustrating the technical and economic advantages of high-pressure frequency converters in pump control in chemical enterprises. Through a technical and economic analysis of various feasible solutions for pump speed-regulating drive devices, it provides a decision-making method for enterprise equipment upgrades. Most piston pumps in chemical plants are driven by fixed-speed electric motors. When the process requires flow regulation, it mainly relies on changing the characteristic curves of the unit and the pump, using bypass diversion to adjust the flow. This results in a significant waste of energy in the bypass, and the flow regulation is manually operated, lacking timely control and feedback. If speed regulation is adopted for the piston pump drive device, the pump flow can be effectively controlled, saving energy and improving process regulation performance while reducing wear on mechanical devices, creating conditions for long-term system operation. The high-pressure ammonia pump in the Luzhou Chemical urea plant requires adjustable speed due to production process needs. The entire system is driven by a 550kW high-pressure asynchronous motor operating at its rated speed, with speed regulation via a hydraulic torque converter and then reduction by a reducer. The transmission system configuration is shown in Figure 1. The key component for system speed regulation is the hydraulic torque converter. However, with prolonged use, the mechanical wear and aging of the hydraulic torque converter are becoming increasingly serious, its performance is declining year by year, its failure rate is increasing, its maintenance cycle is shortening, and equipment maintenance is very difficult. Furthermore, the torque converter currently in use is outdated, imported spare parts are scarce, and ordering new equipment is prohibitively expensive. Therefore, modernization is necessary. [b][align=center]For details, please click: Retrofitting and Technical-Economic Analysis of the Urea High-Pressure Ammonia Pump Speed ​​Regulation System[/align][/b]