Overpressure and negative pressure of pressure ves

Overpressure, negative pressure and preventive measures of pressure vessels in breweries

overview

overpressure of pressure vessels can cause bulging and deformation of vessels, and even explosion, causing casualties and major property losses, which is extremely harmful. Therefore, general manufacturers attach great importance to the harm of overpressure. For example, boilers have been listed as special control equipment. The negative pressure in the pressure vessel often causes damage to the equipment, which leads to the collapse of the pressure vessel and the leakage of its contents, thus stopping production and causing personnel or economic losses. Therefore, negative pressure and overpressure will bring losses to enterprises, which should be highly valued

the following classification describes the causes of overpressure and negative pressure of pressure vessels in breweries and preventive measures

1. Fermentation tanks and other pressurized liquid storage containers

1.1 overpressure

1.1.1 misoperation causes the pressure in the closed container to rise continuously, resulting in overpressure. There are five main situations:

a. after giving back pressure to the pressure container, forget to close the air pressure valve or CO2 valve

b. the pressure gauge of the tank is damaged, which cannot correctly indicate the pressure and blindly back pressure

c. internal leakage of air pressure valve or CO2 valve, including packaging materials, containers, tools and equipment used for food in the process of food production, processing, packaging, transportation, storage, sales and use. The pressure in the container keeps rising. This paper analyzes and compares various high to overpressure

d. do not know the process, blindly back pressure, causing the pressure to exceed the limit value

e. fill the tank with liquid by pump, and the pump is not stopped in time after the tank is full

preventive measures:

a. operate carefully, accumulate experience and lessons, and enhance heart and safety awareness

b. carefully check whether the pressure gauge and valve are damaged

c. install the safety valve and check or calibrate it regularly

1.1.2 the gas in the closed container is heated and expanded or the gas escapes from the liquid, and the pressure is constantly increased to overpressure. The easy situations are:

a. CO2 is generated in the fermentation process, which makes the container continuously increase pressure

b. CO2 is produced during yeast reproduction, which makes the container continuously pressurized

preventive measures:

a. open the emptying pipe

b. regularly observe the pressure gauge on the tank and discharge the pressure in time as required

c. install safety valve on the tank and check or calibrate it regularly

1.1.3 a large amount of gas produced by the chemical reaction of two media in the closed container cannot be discharged (small possibility)

1.2 negative pressure

1.2.1 when steam (or other high-temperature gas) is used to sterilize in the tank, if the inlet and outlet valves are closed by mistake during or after sterilization, in this way, the steam in the closed container will gradually cool down and liquefy, and the space pressure in the tank will be reduced to negative pressure

1.2.2 under the action of gravity or external force (such as pumping), the liquid in the closed container is discharged. If the liquid output is greater than the liquid input, or there is no liquid input at all, the pressure in the container gradually decreases to negative pressure. There are three cases:

after these organic sheets are heated in the infrared furnace, a. the liquid inlet valve is closed, the liquid discharge valve is opened, and the liquid flows out by gravity

b. both the liquid inlet valve and the liquid discharge valve are open, but the liquid inlet volume is small and the liquid discharge volume is large

c. close the liquid inlet valve and pump the liquid in the tank

1.2.3 when the gas in the closed container encounters other media, it reacts violently, the gas disappears, generates liquid or solid, and the space in the tank decreases rapidly to form negative pressure. The common situation is that when brushing the tank, if there is a large amount of CO2 gas in the tank or the back pressure of CO2 gas is used, the CO2 gas encounters caustic soda (NaOH) solution, reacts violently, and the CO2 gas disappears:

preventive measures:

A. understand the relationship between gas pressure and temperature, understand the chemical characteristics of various media in the container, and whether there is a chemical reaction between them

b. avoid misoperation and ensure that the valve is in good condition and the switch state is correct

c. install the vacuum valve and calibrate it regularly

d. before brushing the tank with caustic soda solution, be sure to blow away the carbon dioxide gas in the tank

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