Entry Time：2019-08-16 09:33:22
The raw hydrogen gas and oxygen gas will be generated through H2 generation unit, in which there are the following components with corresponding functions:
● Electrolyzer:
In the electrolyzer, the DM water is decomposed into H2 and O2 within the electrolytic cells with DC power. H2 will be evolved on cathode side of cells and go up through the perforations of cathodic side of electrode plates and hydrogen channels, then flow out from the middle plate of cells. Also O2 will be evolved on the anodes of cells and flow out from the middle plates of cells.
● H2/O2 separator and H2/O2 washer:
Hydrogen and oxygen come separately into H2 separator and O2 separator, where they are cooled by cooling water and separated from the mixture of gas-lye by gravity. After that H2 gas come into the H2 washer for lye drop to be removed which is contained in gas by DM water, at the same time the gas is cooled by coil-piped cooler which is erected in the washer. Finally, the hydrogen through the demister which locates at the top of washer to eliminate the water drop, then flows into the hydrogen drying unit via pneumatic valve for further purification.
Oxygen processing will be the same as H2 processing.
● Lye recycling System:
The alkaline solution (electrolyte) combined together from the hydrogen (oxygen) separators return to the electrolytic cells via the collection pipe and the filter in which the foreign substances will be removed from the solution, then it will be returned to the electrolyzer via lye pump.
● Supplementary of the DM water:
The DM water is fed either into the hydrogen washer or oxygen washer for supplementary of DM water in the hydrogen generating system by the feed-water pump. Also the DM water supplementary system can be used to deliver the lye from the lye tank to the O2 separator for supplementary of lye into the system if necessary.
● Preparation of lye:
The function of lye is to improve the electrical-conduction performance during water electrolysis. Under normal operation condition, the consumption of lye will be nearly zero. Generally, the supplementary of lye will be needed only one time each year if necessary and the quantity will be a little. For preparation of lye, solid caustic potash is put into the DM water tank which is filled with two-third of DM water inside and then the lye pump will be started to agitate and dissolve caustic potash into the DM water.
● Normal Cooling Water System:
Cooling water serves for the following purposes:
A) Cooling the SCR element in the rectifier;
B) Cooling the lye by means of the lye coolers inside of H2/O2 separators and hence the operation temperature of electrolyzer is to be controlled in the range of 80-90 Celsius degrees;
C) Cooling hydrogen and oxygen by the cooler in washer and their temperature at the outlet of cooler is not more than 40 Celsius degrees at the outlet of H2 washer;
D) Cooling the hydrogen purification unit for product H2 to meet the technical specification (dew point -70 Deg.C );
● Gas analysis system:
Hydrogen is sampled to the hydrogen gas analysis system via sampling tube, in which the mini-lye drop is separated from it by the gas-moisture separator, then it goes into the online analyzer to check the O2 content in hydrogen after its pressure will be reduced.
Oxygen is also sampled to the oxygen gas analysis system via sampling tube, in which the mini-lye drop is separated from it by the gas-moisture separator, then it goes into the online analyzer to check the H2 content in oxygen after its pressure will be relieved.
Before the product H2 is transmitted into the corresponding storage tank, it will be sampled into the separated moisture meter to measure their dew-point, the corresponding signal will be sent into programmable logic controller for display and monitoring. The control program will decide the product H2 and product H2 to be sent into their corresponding storage system or not, depending a certain conditions.