Air pollution control unit and air pollution control method, and CO2 recovery unit and CO2 recovery method

An air pollution control unit configured to bring particle-containing gas and washing liquid into contact with each other to collect particles in the particle-containing gas, the air pollution control unit comprising:

• a gas washing column having a gas cleaning section in which the particle-containing gas and the washing liquid are brought into co-current contact with each other;
• a gas cooling column which is disposed downstream of the gas washing column along a gas flow and in which the particle-containing gas that has been cleaned and cooling liquid are brought into countercurrent contact with each other;
• and
• a gas communication path through which the gas washing column and the gas cooling column are made to communicate with each other on a bottom side and through which the cleaned gas that has been cleaned in the gas washing column is introduced into the gas cooling column, wherein
• the gas washing column comprises:
• a washing liquid reservoir section which is disposed on a bottom of the gas cleaning section along the gas flow and in which the washing liquid is dropped and reserved;
• a washing liquid circulation line through which the washing liquid from the washing liquid reservoir section is circulated to a top side of the gas washing column;
• a connection opening on a sidewall of the gas washing column, wherein the connection opening is an inlet of the gas communication path;
• a sloped plate that extends straight downward from a top edge of the connection opening toward a fluid surface of the washing liquid reserved in the washing liquid reservoir section and toward an inside of the washing liquid reservoir section, wherein the sloped plate regulates the gas flow flowing through the connection opening;
• an open path between the sloped plate and the fluid surface, wherein the open path causes the particle-containing gas to flow into the gas communication path;
• and
• a liquid level meter that measures an amount of the washing liquid reserved at the washing liquid reservoir section,
• a tip of the sloped plate is a free end, and
• the air pollution control unit controls a liquid level in the washing liquid reservoir section in response to a change in a gas volume of the particle-containing gas introduced to the gas washing column.