A start-up method of ammonia compressor unit

Abstract

The invention discloses a start-up method for an ammonia gas compressor unit. The main steps are: (1) preparatory work (dry gas sealing, nitrogen replacement) before start-up; (2) starting the ammonia gas compressor unit and warming up the machine; (3) The speed of the ammonia gas compressor unit passes through the critical speed band to supplement the first-stage inlet separator and the second-stage inlet separator; (4) After the speed of the ammonia gas compressor unit reaches the minimum speed of the governor, increase its speed to normal During the speed-up process, adjust the flow rate of the first-stage anti-surge valve and the second-stage anti-surge valve. At the same time, when the pressure difference between the third-stage outlet pressure and the dry gas seal balance pipe is ≥0.5MPa, the The dry gas sealing gas source is switched to the outlet process gas of the unit; (5) After the speed of the standby unit reaches the normal operating speed, open the ammonia gas valve A and the ammonia gas valve B, and the start-up is completed. The start-up method realizes the independent start-up of the ammonia compressor unit, and there is no ammonia emission during the start-up process, which is clean and environment-friendly.

Description

technical field [0001] The invention relates to the technical field of ammonia gas compression, in particular to a method for starting up an ammonia gas compressor unit. Background technique [0002] The ammonia compression refrigeration process is mainly composed of four parts: compression, cooling and condensation, throttling expansion and evaporation. The ammonia gas is compressed to a certain pressure by the ammonia compressor, and then cooled and condensed into liquid ammonia by a water cooler, and the liquid ammonia is vaporized to form The process of ammonia gas absorbs a lot of heat, so it can provide cooling capacity for other devices, and it is usually used to provide cooling capacity for air separation and low-temperature methanol washing devices in current production. The core equipment in the ammonia compression refrigeration process is the ammonia compressor unit, which includes an ammonia compressor and a steam turbine. At present, the system pressure of the ...

AI Technical Summary

Problems solved by technology

At present, the system pressure of the existing ammonia compressor unit is controlled at 0.15-0.18MPa before starting up. After starting, due to the long warm-up time (35min and 50min), the system pressure will continue to rise due to nitrogen leakage. In the process, due to the continuous increase of the rotational speed, the system flow rate continues to increase, especially between the critical rotational speed bands, the inter-stage flow rate will exceed the range, resulting in high bearing temperature, the compressor outlet is forced to vent and reduce the pressure, and after entering the normal rotational speed, it needs more Excessive exhaustion of inert gas for a long period of time causes excessive ammonia loss, and at the same time poses a greater pressure on environmental protection emissions

The ammonia loss of the ammonia compressor unit is about 6-12 tons per start-up, which greatly increases the start-up cost of the ammonia compressor unit

Images