Issues regarding the commissioning of the steam system.
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Our factory has steam available in four different pressure levels. First, superheated steam is introduced from outside the factory; then, through a temperature and pressure reducer (with boiler water as the cooling medium), high-pressure steam is produced. Subsequently, by further reducing the temperature and pressure, medium-pressure, low-pressure, and very low-pressure steam are obtained. The boiler water is supplied by water from the deaerator through a pressure pump. The current problem is that during the testing phase, the boiler water can only be replenished with desalinated water. However, there is a minimum temperature requirement for the boiler water entering the temperature reduction valve (at least 100°C). As a result, tasks such as purging the steam pipelines and conducting trial operations during the testing phase cannot be carried out without boiler water to produce steam at various pressures. I’m seeking advice from experts – what should be done in this situation? We do have a condensate recovery system here, but isn’t it unrealistic to use the recovered condensate to replenish the boiler water? After all, this is far too slow.
If not, I won’t turn it on; it’s okay! When the pressure drops, the temperature naturally falls; it is mainly the control valve at the back that comes under stress. After introducing steam, the opening degree of the first valve must be kept low, just enough to allow flow. First, pump water out systematically; water hammer is an inevitable phenomenon during this process, so it must be strictly controlled! Once the water hammer becomes severe and the intensity seems to increase, immediately close the first valve and wait patiently for the water to drain completely. After the water is drained, the pressure throughout the entire pipeline network increases gradually. After the pressure reaches that of the low-pressure system, a check is performed; once it reaches the pressure of the low-pressure system, another check is carried out; and after it reaches the pressure of the medium-pressure system, yet another check is done. Once the entire system is in operation, condensate will be generated naturally, after which the desuperheating water can be gradually introduced. At this point, the boiler is started, and deoxygenated water is supplied. Even if the steam consumption does not meet the conditions for starting the boiler, it is still necessary to maintain operation at a minimum load level, while appropriately reducing the amount of steam used in the outer tubes. If the steam from the external pipe is very stable and its volume meets the needs of the entire plant, it may not even be necessary to operate the boilers.
Thank you, sir. If we use your method of gradually reducing temperature and pressure solely through valves, wouldn’t that put too much pressure on the downstream valves? After all, it involves purging the steam pipeline, and the steam has to be turned on and off from time to time； We discussed this matter with our management yesterday. The issue is that since we don’t have boiler water, we’ll use desalinated water as a substitute for now. All that’s needed is to be careful with the temperature and pressure reduction devices, and to introduce the water slowly ；
At the beginning, one must drive slowly; if driven too fast, the pipes will expand, so reduce the cooling water flow – there’s no need to rush it. When the load is 1/3. It’s fine to turn it on
I’m not sure who specified that a thermostat of yours needs water at a temperature above 100°C; it’s essentially a nozzle, and there’s no problem using cold deionized water.
I’d like to ask gently: if the boiler isn’t turned on, where does the steam come from?