Detection and control method suitable for flow deposition of ammonium salt of hydrogenation air cooler

Abstract

The invention discloses a detection and control method suitable for the flow deposition of ammonium salt of a hydrogenation air cooler, which comprises the following steps: controlling the monitoring temperatures of thermocouples in zones A and B which are 1-3m distance away from the joint of the outlet of an inlet channel and a first row tube bundle and correspond to fluid medium inlets to be lower than the dew-point temperature of water, and the monitoring temperatures of thermocouples at both ends of a channel and a middle zone which are 0.2-1m distance away from the joint of the inlet of an outlet channel and a fifth row tube bundle to be higher than the crystallization temperature of NH4HS, and carrying out regulation and control through water injection rate, water injection temperature, fan speed or blind window opening; controlling the deviation of the monitoring temperatures of the thermocouples in the zones A and B which are 1-2m distance away from the joint of the inlet of afirst middle channel and a tube bundle and the deviation of the monitoring temperatures of the thermocouples at both ends of the channel and the middle zone to be less than 10 percent; and otherwise,increasing injected water to reduce the temperature deviation. In the detection and control method suitable for the flow deposition of the ammonium salt of the hydrogenation air cooler, the phenomenon that NH4Cl deposition is caused because a liquid water dry zone is generated at the 1-3m position of the inlet of the air cooler is avoided, the phenomenon that washout is caused because NH4HS deposition is generated in an end tube pass is also avoided, and whether flow unbalance is generated on the air cooler or not can be detected.

Description

technical field [0001] The invention relates to on-line monitoring of flow corrosion of equipment systems in the chemical industry, in particular to a detection and control method suitable for the flow deposition of ammonium salts in hydrogenation air coolers. Background technique [0002] Since the Isocracking hydrocracking technology invented by Chevron Company was put into use in 1959, after more than 60 years of rapid development around the world, the hydrocracking reaction effluent air cooler (Reactor Effluent Air Coolers, referred to as REAC) system has been used in petroleum The chemical industry occupies an important position. With my country's accession to the WTO, the import of high-sulfur low-quality crude oil from the Middle East has increased year by year. Correspondingly, the hydrocracking units of many refineries have successively carried out high-sulfur capacity expansion transformation, and then there have been many perforations of the tube bundles of the hy...

AI Technical Summary

Problems solved by technology

During the investigation, it was found that the water injection methods of the hydrogenation REAC system of major oil refining enterprises are various. The water injection points include single-point water injection and multi-point water injection, and the water injection volume is also very different. The difference can easily lead to unbalanced flow field distribution of multiple parallel REAC systems, so that the flow velocity of the multiphase flow medium in the tube bundle is partly fast and partly slow. is completely washed away, and in the presence of liquid water, corrosion under ammonium scale or multiphase flow erosion failure accidents occur

For the unbalanced flow field in the hydrogenation REAC system, the existing technology cannot achieve effective detection and control. Specifically, when the ammonium salt crystallization deposits in the tube bundle and whether the tube bundle is blocked, it cannot be effectively supervised, so that many hydrogenation The flow corrosion risk of the REAC system is extremely high, and there is a huge potential safety hazard of leakage at any time

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