In the chlor-alkali industry, the transport or pressurization of chlorine and hydrogen is mainly carried out in both centrifugal and liquid ring types. The centrifugal type chlorine press has a large gas transmission volume and high efficiency, but it is required to dry the chlorine gas to a water content of less than 50×10-6 (mass fraction), and it is necessary to increase the investment of the chlorine gas drying device, for example, when the intake air amount is less than 1400 m3/h, Less efficient.
At present, the high-speed multi-axis centrifugal type chlorine press can be used for the transportation of chlorine gas with an annual output of 30,000 to 70,000 tons of caustic soda. The number of small and medium chlor-alkali plants is the majority, and the use of liquid ring chlorine pumps is still large. In the high-pressure liquid chlorine process, the chlorine gas with a discharge pressure of about 14 bar is pressurized, and a double-suction chlorine pump is used.
The chlorine pump should be combined with a gas-liquid separator, a sulfuric acid cooler, a circulation pump, a valve, a pipeline, a meter, and the like. Complete supply on the common base. For the transportation or pressurization of chlorine gas, regardless of the scale of the device, the liquid ring type chlorine compression unit is generally used, the chlorine gas pump and the liquid gas separator, the water cooler, the valve, the pipeline, the instrument, etc. are assembled on a common base. goods. From the safety point of view, the liquid ring pump is also widely used for the transportation or pressurization of dangerous gases such as acetylene and vinyl chloride.
Working conditions and selection requirements
(1) Chlorine gas is a toxic gas. Chlorine gas is a flammable and explosive gas. It is not allowed to leak. The reliability of the shaft seal is strict and should be mechanically sealed.
(2) The chlorine gas pump uses concentrated sulfuric acid as the working fluid. The heat of the chlorine gas is absorbed by the concentrated sulfuric acid. The concentrated sulfuric acid is required to be closed. The gas-liquid separator, the sulfuric acid cooler, the circulation regulating valve and the liquid flow mirror should be installed. For the forced circulation type, a sulfuric acid circulation pump is also added. For the chlorine pump, in order to avoid scale formation in the liquid ring pump, the drinking water is usually used as the working fluid, and the heat load of the closed loop cooler is also introduced according to foreign data, which can be taken as 90% of the shaft power.
(3) Chlorine gas pumps are made of inexpensive cast iron, and the corrosion resistance of cast iron materials in chlorine-saturated concentrated sulfuric acid is limited. After the valve surface is corroded, the gap increases and internal recirculation occurs, which reduces the volumetric efficiency. It is required that the chlorine pump can check and adjust the clearance of the valve surface without removing the pump to prevent the pump performance from deteriorating. Most domestic chlorine pumps use austenitic stainless steel multistage centrifugal pumps.
