Abstract: The present invention relates to a method for purifying key intermediates of Citalopram, i.e. 4-[4-(dimethylamino)-1-(4-fluorophenyl)-1-hydroxybutyl]-3-hydroxymethylbenzonitrile and a salt thereof. The method comprises dissolving crude 4-[4-(dimethylamino)-1-(4-fluorophenyl)-1-hydroxybutyl]-3-hydroxymethylbenzonitrile (compound of formula I containing formaldehyde impurity) with an organic solvent, adding a washing solution, controlling the temperature, stirring, leaving to stand for layering, and removing the aqueous layer, so as to obtain a purified organic solution of 4-[4-(dimethylamino)-1-(4-fluorophenyl)-1-hydroxybutyl]-3-hydroxymethylbenzonitrile. The method provided by the present invention can effectively remove aldehyde group-containing impurities in the intermediate. The method of the present invention has the advantages of simple operation, cheap raw materials and mild conditions, and is suitable for large-scale industrial production.

Abstract: A refrigeration system and a control method thereof. The refrigeration system includes a compressor and a condenser, and further includes a first throttling device for receiving liquid refrigerant from the condenser; an ejector having a high-pressure fluid inlet, a fluid suction inlet and a fluid outlet, the high-pressure fluid inlet of the ejector is connected to the first throttling device, the fluid outlet of the ejector is connected to a flash tank, a gas-phase outlet of the flash tank is connected to a compressor inlet, a liquid-phase outlet of the flash tank is connected to an evaporator via a second throttling device, and the evaporator is connected to the fluid suction inlet of the ejector; and a controller configured to control an opening of the first throttling device based on a pressure difference between the fluid outlet and the fluid suction inlet of the ejector.

Abstract: The present invention relates to a gas-liquid separator, including a body enclosing a cavity; a gas outlet attached to the top of the body and communicated with the cavity; a liquid outlet attached to the bottom of the body and communicated with the cavity; and an input tube constructed to include a curve shape extending outside the body and communicated into the cavity from the external of the body. The gas-liquid separator of the present invention has got the advantages of a simple structure, easy manufacturing, convenient mounting, and the like, and can separate a gas-liquid two-phase mixture efficiently, thus providing a purer gas flow and a purer liquid flow for downstream processing apparatuses and improving the overall efficiency of the system.