Can the fixed-drain and continuous-drain systems of a waste heat boiler use the same container?
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As stated in the title, the evaporation rate is 3 T/H and the steam pressure is 1.9 MPa. Can a fixed-discharge expansion vessel and a continuous-discharge expansion vessel share the same vessel? Should I bring a safety valve?
It cannot be used publicly; a safety valve is required. Also, the evaporation rate is too low; using continuous or periodic drainage doesn’t make much sense in this case. If adding it is necessary, use a continuous arrangement; a fixed arrangement is not required.
Reply to 2# tangdiscover: Then what size should the row of jars be? Is it okay to connect the fixed pump to this tank?
Sure, it’s fine – there’s basically no conflict. Besides, the waste discharge tank operates at atmospheric pressure; only the pressure rises slightly during the discharge process, so there’s no need to install a safety valve
This post was last edited by zgj2405 on 2011-12-4 at 12:38. It should be possible, but it’s better to consult the manufacturer for details
To calculate the continuous blowdown expansion vessel, the following formula can be used; typically, medium-pressure boilers are equipped with first-stage continuous blowdown expansion vessels with a pressure of 0.15 Mpa. It can be calculated using the following formula: V = VV + VW = Db1 × Df × v / R + (20–30%) × VV, in cubic meters. Where: V is the total volume of the continuous wastewater expansion tank, in cubic meters ； VV—Steam volume of the continuous blowdown expansion tank, m3 ； VW—Water volume of the continuous discharge expansion tank, m3 ； Db1—Continuous wastewater discharge rate of the boiler, Kg/h ； v – specific volume of steam at the pressure in the expansion vessel, in m3/Kg; R – maximum allowable strength per unit volume of the drainage expansion vessel, typically ranging from 800 to 1000 m3/(m3·h); Df – amount of vapor generated per kilogram of wastewater, calculated using the following formula: Df = hd×η – hs/xr, in Kg/Kg. Where: hd – enthalpy of saturated water at the pressure in the steam drum, in KJ/Kg; η – heat loss coefficient due to conduction in the pipes between the steam drum and the expansion vessel, taken as 0.98 ； hs——Enthalpy of saturated water at the pressure in the expansion vessel, KJ/Kg ； x—steam dryness degree of the expander, taken as 0.97-0.98 ； r—Latent heat of vaporization at the pressure in the expansion vessel, KJ/Kg. Regular drainage is used to remove the deposits from the steam drum and headers of the boiler, thereby improving the quality of the boiler water. It is advisable to send this drained water to a wastewater cooler for heating and softening, or to demineralized water, so as to reduce its temperature to below 50 degrees Celsius before discharge. Regular drainage can also be handled by using a dedicated drainage expansion tank
LS is absolutely right; LZ can refer to the formula and calculate it by themselves
It’s completely fine. Your boiler is small, so the amount of wastewater generated will likely not be very large either. As long as your wastewater storage tank isn’t extremely small and the wastewater valve isn’t particularly large, it won’t have much impact on the tank. The top of the sewage tank can be connected to the atmosphere via a vent; no valves are needed.
Can what was mentioned on the 6th floor be used for fixed schedule calculations? Are there any specifications in this regard?