DEAR Biogas purification unit.When the gas with higher pressure expands through the expander, the energy (enthalpy) of the gas itself is reduced and the temperature is significantly reduced because the gas drives the impeller to rotate and outputs work. It has the ability to take away heat, which is the energy recovered before expansion after heat absorption. Therefore, the difference of energy (enthalpy) before and after expansion of expander is the cooling capacity of expander.DEAR Biogas purification unit.According to the maximum cooling capacity and the cooling capacity required for cooling and liquid accumulation, the start-up time of the unit also needs to be more than 36 hours. Large air separation units are generally equipped with liquid oxygen storage tanks as emergency standby oxygen. If necessary, it is theoretically possible to fill the tower with liquid oxygen to shorten the start-up time of the air separation unit.Mixed type: its characteristic is that the heat exchange of cold and hot fluids is realized in the process of direct mixing. In the process of heat transfer, there is also material exchange, such as nitrogen water precooler.
Close the oxygen regulating butterfly valve and fully open the dirty nitrogen and pure nitrogen regulating butterfly valve. Turn off steam source of steam heater. Cut off the power switch of electrical equipment and make it in the start position. After finding out the cause of the power failure and eliminating the fault, make preparations for the start-up.DEAR Biogas purification unit.The cooling water used in the air compressor cooler is generally the industrial water without softening treatment. When the water temperature is high, the bicarbonates such as calcium and magnesium in the water will decompose into hard deposits on the pipe wall, which is called scale. The amount of scale formation is related to the water temperature, time and water quality.When the main cooler leaks seriously, a large amount of nitrogen with higher pressure leaks into the low pressure oxygen side, the pressure of the upper and lower towers and the purity of the product will change significantly, until the normal production cannot be maintained and the unit stops. When the main cooler leaks slightly, the pressure of the upper and lower towers will not change significantly, and the purity of liquid oxygen in the main cooler will not decrease significantly.
DEAR Biogas purification unit.In normal operation, the temperature of intermediate extraction is - 110 ～ - 120 ℃. At this time, the water has been basically removed, the carbon dioxide is removed by the adsorber, and the air entering the expander will be a clean gas without water and carbon dioxide. However, in the initial stage of start-up, the accumulator is still in the cooling stage.DEAR Biogas purification unit.During the separation of oxygen and argon in the crude argon column, most of the oxygen in the gas argon fraction is condensed during the rising process, while the nitrogen component with low boiling point is non condensing, which will all remain in the crude argon, so that the nitrogen content in the crude argon will be tens of times higher than that in the argon fraction.DEAR Biogas purification unit.When designing this kind of condensing evaporator, the value of relative liquid level is generally slightly higher, H = 0.5 or more. When operating at this height, the working condition is more stable and easy to operate. Now considering safety first, it is recommended to soak the plate condensing evaporator in liquid oxygen at home and abroad, slightly sacrificing the heat transfer effect to ensure the safety of the equipment.
