The cold box has high efficiency, compact structure, suitable for multi-phase flow and other characteristics, but its flow channel is small, easy to block, not corrosion-resistant. In use, we should pay attention to the components and purity of the entrance fluid, in the entrance according to the design requirements of the installation of a certain number of mesh filters or filters; and in the cold box import and export installation of precision pressure gauges, regular monitoring, when the pressure difference increases to a certain extent, that is, need to cut out the cold box to clean up the filter or need to be injected into the thawing of methanol and other substances. Running leakage is also a common phenomenon in the use of plate-fin heat exchanger, this is because the plate-fin heat exchanger contraction at low temperatures, may cause some flange gas leakage, therefore, for the operation of the flange in -100 ℃, should be bolted cold to tighten. Usually, when the plate-fin heat exchanger gradually cools down to below -30℃, tighten all the flange bolts. When the normal operating temperature is reached and no leakage is found in the flange, the flange bolts should not be tightened too tightly to avoid damage to the gasket. When the frost phenomenon affects the cold handle tightening, the common method is to inject a methanol solution on the bolt. In addition, attention should be paid to the following points: ① The operator must strictly follow the operating procedures. ② In the early stage of start-up, the cracked gas flow should be gradually and slowly increased to the cold box system, to ensure that the demethanization and the temperature drop of the cold box system is uniform, and to make it easy for the operator to monitor the pressure of the cold box system. ③For the unit using S&W process, the initial start-up cooling rate of the cooled condensate separator should be limited to the specified range (generally 170℃/h). ④ When an abnormal situation occurs, the cause should be quickly identified and dealt with in time to avoid stopping accidents as far as possible under the principle of protecting the safety of operators and equipment. ⑤ The outlet of the cold box is equipped with a low temperature interlocking protection device, if the interlocking action occurs, the outside operator should carry out the necessary pressure relief treatment on the isolated pipeline. (6) Before the system is put into operation, carefully check whether the bypasses of the pilot valve and safety valve have been completely closed. Must be diligent in checking the system material leakage, found that the problem promptly contact the relevant personnel.