May I ask, must the boiler steam be continuously vented before it is connected to the grid?
Thread Content
Hello everyone. I’ve always had a question: with the steam generators in my workplace, the steam produced during the ignition and heating process has to be vented, which is a huge waste. Is it possible to avoid venting it, and instead raise the pressure just like in a pressure cooker at home, by shutting off the venting mechanism? Connect to the grid once the conditions are met? I am lacking in knowledge and skills; I earnestly ask for your guidance.
Whether it can be integrated into the pipeline network depends on the operating load of your installation; primarily, it depends on the amount of steam required, as well as the direction of flow of the steam (to avoid local stagnation).
I’ve thought about this too; releasing such a large amount of steam is a waste, but there’s no place that requires such a high instantaneous steam volume
This post was last edited by pzhmotor on 2018-8-3 at 16:13. It is difficult to achieve in practice; the pressure cooker heats up relatively slowly, and it has a vent valve that releases steam in small amounts to prevent overpressure. There is also a safety rupture disc inside the pressure cooker. The steam drum of the boiler has a relatively small capacity, and it is equipped with a drain valve (in larger boilers, it is an electric drain valve). When starting up a CFB boiler, adjusting the opening degree of the drain valve according to the pressure inside the steam drum is essential for ensuring safety. Especially when adding coal or removing the oil guns later on, any carelessness can easily lead to overheating and coking, as well as shutdown due to low temperatures; in such situations, it is crucial to maintain stable pressure in the steam drum. It is important not to allow the safety valve to activate repeatedly, as this would cause pressure fluctuations and problems with the pressure-bearing components of the boiler, which is very dangerous. The connection of boilers is conditional: the pressure in the boiler drum must be roughly the same as the pressure in the steam network to which it is connected (this is specified in the boiler operator’s manual; I recall that before connecting two low-pressure saturated steam boilers, the outlet pressure of the boilers should be about 0.05 Mpa lower than the pressure in the main pipe). It is also necessary to carry out a warming-up procedure before the connection valves can be opened; if the pressure difference is too large, it is not possible to open those valves (this is especially true for manual valves). During the process of connecting the boilers, in order to maintain stable pressure, the load on each boiler needs to be adjusted, and venting steam seems to be the only solution. Production organization is carried out in accordance with the principles of \"safety, stability, and efficiency\", with safety always taking precedence. If it is truly necessary to recover this portion of steam, consider options such as heating the water in the desalination tank (which also seems to be uneconomical). It should also be noted that a reliably functional silencer must be installed on the drain valve.
That makes sense. But really, can’t it be pressurized in a sealed environment? As long as safety can be ensured.
I’ve been informed that, at least for now, the information I have is extremely difficult to obtain.
These past two days, our company has successfully implemented a measure to utilize the steam generated as a by-product of one of its units without releasing it into the atmosphere; the steam is connected to the grid as soon as the pressure in the steam drum reaches the required level. At that time, the flow rate to the grid was only 5 t/h, but this approach has eliminated the noise caused by steam being released into the atmosphere, which disturbed the local residents.
A low-pressure waste heat boiler, right? We also have two 5-ton rotary kiln flue gas waste heat boilers here, as well as many smaller waste heat boiler evaporators. Steam is first fed into the steam drum of the waste heat boilers, which gradually raise the temperature; the load on the larger boilers can be adjusted slightly, and there is no need to empty them. I thought you were referring to connecting two boilers together after starting them up – the procedures for doing this are in the boiler operator’s manual. Why don’t you try connecting the two boilers with an engine? This approach is not realistic; the exhaust pressure cannot be stabilized.
Those with steam engines are indeed different; the pressure requirements need to be stable, while smaller boilers are indeed simpler.