Why is cooling water needed in the gas-liquid separation tank?

The main purpose of adding cooling water is to lower the temperature in the gas-liquid separation tank, allowing some of the water vapor or other components that can condense into a liquid state to do so, thereby facilitating better gas-liquid separation. In a vacuum system, adding cooling water also reduces the volume expansion of gases due to temperature rise during pumping, maintaining the system’s effective pumping rate while protecting the pump and the system from damage caused by high-temperature gases. Installing a liquid separation tank and a water seal at the outlet of the ejector pump can prevent liquids in the high-pressure mixed gas from entering the vacuum system, thereby ensuring the stable operation of the system. Your understanding is correct. .

The drawings are acceptable. Generally, a liquid ring vacuum pump is also connected to the exhaust gas system; in the vacuum level range of 0 to 900, the liquid ring pump is used, while in the range from 900 to full vacuum, a steam jet pump is employed. This approach helps save steam usage, and it prevents the steam jet pump from being activated suddenly, which could otherwise cause flooding in the upstream vacuum system. There are two cooling water sources, located before and after the steam jet pump respectively. You can think of it this way: inside the upstream vacuum TK are water and stearic acid, which is one of the ingredients used in ordinary soaps; it is a solid at room temperature, but it melts when heated to above 50 degrees. At this point, the reactor is at 80 degrees, and vacuum pumping begins in order to remove water and purify stearic acid. If the steam jet pump is turned on immediately, the vacuum level drops rapidly; at this point, a large amount of water vaporizes, causing the liquid level to fluctuate sharply, which leads to liquid entrainment and flooding. In such cases, the cooling water before the jet pump can help cool the material, allowing it to flow back into the vacuum tank, while the protective nitrogen atmosphere is drawn into the pump. At this point, you find that in the pipe leading from the cooling water to the steam jet pump, stearic acid is likely to accumulate there, as the cooling water has lowered the temperature below the melting point; hence this is a location where blockages often occur. Of course, the advantage of a steam jet pump is that its pump body can handle materials prone to forming solids; whereas in the case of a liquid ring pump, the impeller may get damaged. The cooler at the outlet of the jet pump is used to cool the steam, thereby producing condensate that can be easily collected. Since there is still a small amount of material present, and stearic acid is insoluble in water, this water can be left to stand so that the layers separate, allowing the material to be recovered. Of course, it can also be treated as wastewater, because if condensation does not occur here, the steam will flow downward to the incinerator or scrubber tower, which would result in an excessive load on the downstream systems. The liquid that is drawn up vaporizes easily; it’s similar to when you boil water – at 100 degrees, the water vaporizes. If you measure the temperature of both the water and the steam, it will be 100 degrees regardless of the intensity of the heat used. At this point, the steam is saturated, and any loss in the pipeline or cooling effect will result in the formation of condensation.

I’ve learned a lot; your answer seems to have expanded my knowledge further. What I was thinking was to directly draw the vapor phase from the TK to achieve the desired working vacuum level, after which the process could be stopped. It’s a simple idea: if it’s just a negative-pressure storage tank that needs to be evacuated and the required vacuum level for the vapor phase isn’t very high, then the liquid phase that may form will consist only of droplets or vapor carried along with the gas. In that case, all that’s needed is to connect a heat exchanger to condense those droplets and separate them out. What troubles me is that this evacuation process doesn’t seem to generate liquid as a result of pressure changes; it’s merely gas carrying droplets, so separation of the liquids is sufficient； If it’s a dry furnace with only a gas-solid phase, and a vacuum is created before starting up, with an operating temperature of over 1,000 degrees, are then only a filter and a check valve necessary?

There are probably two main considerations: first, the materials need to be recycled, and a higher concentration of the materials in the early condensation stage facilitates recycling； 2 is that cooling and condensing the exhaust gases can reduce the volumetric flow rate as well as the amount of material carried in the exhaust gases, thereby reducing the load on the exhaust gas treatment unit. Generally, after steam injection, there should be an exhaust gas treatment system with circulating water spray, followed by a fan or vacuum pump