A method for airtight recovery and operation voltage stabilization control of tail gas from atmospheric pressure storage tanks in refining and chemical enterprises

Abstract

The invention relates to a method for airtight recovery and operation and pressure stabilization control of the top tail gas of a normal-pressure storage tank in a refining and chemical enterprise, which is suitable for the production needs of the refining and chemical company. After the steam is pressurized online, it is sent to the cooler to cool to 45°C. After gas-liquid separation, the non-condensable gas enters the low-pressure gas flare system of the refinery, and the condensate flows back to the sewage storage tank under self-pressure. Its normal operation is controlled in sections. When the top pressure is 0~0.3kPa, the nitrogen regulating valve is opened, and the steam regulating valve is closed; when the tank top pressure is 0.3~0.5kPa, the nitrogen regulating valve is closed, and the steam regulating valve is closed; when the tank top pressure is 0.5~1.5kPa, the nitrogen regulating valve is closed , the steam regulating valve is opened; the tank top pressure is ≥1.5kPa, and the control gate valve is opened. The invention introduces the pressurized exhaust gas at the top of the atmospheric storage tank into the low-pressure gas flare system of the refinery, realizes the purpose of zero discharge and solves the problem of low operating pressure of the atmospheric storage tank.

Description

technical field [0001] The invention relates to a method for recovering the tail gas at the top of a normal-pressure storage tank in a refining and chemical enterprise and for controlling the operation and stabilizing the pressure. Background technique [0002] Atmospheric storage tanks in refining and chemical enterprises mainly include acid water tanks, oil product tanks, alkali slag tanks, and coking cold coke water tanks. According to the "Code for Design of Vertical Cylindrical Welded Oil Tanks" (GB50341-2003), the design pressure of fixed-roof oil tanks should be normal pressure or close to normal pressure (negative pressure should not be less than 0.49kPa), when it meets the standard appendix A Relevant regulations, the maximum pressure is 6.0kPa, the general operating pressure range is -0.49 ~ 2.0kPa, and the operating flexibility is small. In order to avoid damage to the tank due to excessive positive pressure or excessive negative pressure during use, the design o...

AI Technical Summary

Problems solved by technology

In order to avoid damage to the tank due to excessive positive pressure or excessive negative pressure during use, the design of direct access to the atmosphere is generally adopted, resulting in the release of high concentrations of hydrocarbons, benzene series, hydrogen sulfide, and phenols during storage. Harmful gases such as mercaptans and mercaptans are difficult to seal and recover, and become the main source of processing loss and pollution source of excessive discharge of volatile organic compounds (VOC) in refining and chemical enterprises. Environmental pollution caused by emissions

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