Large air separation FAQ

Shell and tube air separation heat exchanger is the most representative wall heat exchanger. It has a long history of application and is still dominant in all heat exchangers. Shell and tube heat exchanger is mainly composed of shell, tube bundle, tube sheet and head. Most of the shell is round, and there are parallel tube bundles inside. Both ends of the tube bundle are fixed on the tube plate. In shell and tube heat exchanger, there are two kinds of fluids for heat exchange. One kind of fluid flows in the tube, and its stroke is called tube side. The other flows outside the tube and its stroke is called shell side. The wall of tube bundle is the heat transfer surface. In order to improve the heat transfer coefficient of the fluid outside the tube, a certain number of transverse baffles are usually installed in the shell. The baffle can not only prevent the short circuit of the fluid and increase the velocity of the fluid, but also force the fluid to flow through the tube bundle man

When the exhaust temperature of the piston compressor is higher than the design value, the most direct impact is that the lubricating oil is carbonized, which leads to the compressor parts burned out because of not getting good lubrication. If the temperature of the compressor is too high during actual operation, the cause should be analyzed in time and corresponding preventive measures should be taken. The following methods can be used for reference in practice. 1. Reducing the inlet air temperature can directly reduce the exhaust temperature. Check the intercooler to ensure the cooling effect of the intercooler. 2. The installation of the valve and the selection of the spring should be standardized to ensure the normal operation of the valve and minimize the loss of inlet and outlet pressure. 3. Strengthen the cooling of cylinder to ensure the normal compression process index. 4. Internal leakage is the main reason for the increase of exhaust temperature. 5.For multist

Generally, the main reason for the vibration of piston type oxygen compressor is the action of alternating load. There are two kinds of alternating loads: one is the unbalanced inertia force, the other is the interference force caused by the strong gas pressure pulse in the gas pipeline caused by the discontinuous gas supply of the compressor. The vibration caused by unbalanced inertia force can be eliminated and reduced from the structure of the machine itself. The specific methods are as follows: reasonably arrange the crank stagger angle; properly select the mass configuration of reciprocating parts. In addition, the basic design and manufacturing process of the compressor should also strictly comply with the technical specifications. For the vibration caused by air flow pressure pulse, a buffer can be installed near the cylinder exhaust pipe nozzle; the appropriate installation position of orifice plate should be selected on the gas flow channel; the shock absorber should be

When the main condenser evaporator leaks seriously, a large amount of high-pressure nitrogen will leak to the low-pressure oxygen side, and the pressure of the upper and lower columns and the purity of the product will change significantly until normal production cannot be maintained. When the main condenser evaporator leaks slightly, the pressure of the upper and lower columns will not change significantly, and the purity of liquid oxygen in the main condenser evaporator will not decrease significantly. The common phenomenon is that the purity of the gas and liquid oxygen in the main condensing evaporator is very different, and the gas concentration is lower than that in equilibrium with liquid oxygen. For example, the concentration of liquid oxygen is 99% and that of gaseous oxygen is 96%, that 7 main cooling pipes were found to be leaking during maintenance. The common causes of leakage are as follows: 1. Pipes are worn due to mutual vibration. For long tube condensing evap

Expander is a kind of mechanical equipment that uses compressed gas to expand and depressurize, so that the gas temperature can be reduced to obtain the cooling capacity. In the air separation unit, the expander is an important equipment to provide cooling capacity for the air separation unit, and its cooling capacity accounts for 80% - 90% of the cooling capacity of the air separation unit. The main structural forms of expander are piston type and turbine type. The piston expander is suitable for air separation process with large pressure drop and small flow rate because of its convenient manufacture and low speed. Turbine type has the characteristics of large gas flow, high efficiency, stable and reliable operation and no friction parts. Due to the low pressure air separation process used in large air separation units, the pressure drop and unit cooling capacity are very small, and because the expansion air is sent to the upper column for rectification, the expander is requi

After a long-term operation of the air separation plant, the components in the cryogenic equipment and pipelines in the distillation system will be blocked due to ice or mechanical powder, which will increase the resistance of the fractionator. When the air separation plant has been in normal operation for about 2 years, the fractionator system should be heated and thawed to remove these deposits. When the molecular sieve adsorber and the main heat exchanger have water inflow or other faults, it is also necessary to stop and heat up. In general, the following methods will be used for heating and thawing.

After a long-term operation of the air separation plant, the components in the low-temperature equipment and pipelines of the distillation system will be blocked due to the internal precipitation of icing or mechanical powder, which will increase the resistance of the fractionating column. Therefore, after the normal operation of the air separation plant for about 2 years, the fractionating column system should be heated and thawed to remove these sediments. When the molecular sieve adsorber and the main heat exchanger have water or other faults, they must also be stopped for heating. The following describes several heating and thawing operation methods: