I am planning to use a superheated steam and water drum in my plant to heat up the water (actually the steam flow rate is not that much to extract work). I would like to know if it is conceptually correct and feasible injecting superheated steam into water to heat it up. Thanks in advance, Reza.
I actually know in deaerator is where steam is injected into boiler feed water to degas the water, here I would like to know if this can be used as a heating process for water.
Thanks
In deaerator boiler feed water (compressed liquid) is also heated and becomes saturated liquid. That means you may heat liquid water by using superheated steam. The final temperature depends both on mass flow rates of the streams and on their enthalpies.
Deaerator has low pressure stream via sparger pipe at lower part of drum where it stores water which itself act as a water heating to maintain water at certain temperature. Hence, you can use the same working principle keeping in mind flow rate, pressure and temperature requirement for both fluid (e.g. steam and water).
The following information may be useful for your research
Thermodynamically, superheated steam and liquid water cannot coexist under thermodynamic equilibrium, as any additional heat simply evaporates more water and the steam will become saturated steam. However this restriction may be violated temporarily in dynamic (non-equilibrium) situations.
you can use the formula mass flow rate of water x Cpx Delta T= mass flow rate of steam x Enthalpy of steam
Hi Reza
Before getting involve of the technical details, I would like you to approach to your question like a project manager. Did u study the feasibility of your design on paper? Does it satisfy thermodynamic equations? If so, you can go ahead and move to the next step. and next step will be defined based on the nature of your project. Is that an industrial project? or an academic project?
If you want to heat the water with a stream of steam superheated water, at elevated pressures (superior to 15 bars), there is no problem. With relation to liquid pressure and for a heating by direct contact, the steam will then undergo a desuperheating, a condensation and subsequently a subcooling to release both sensible heat and latent heat respectively. The temperature of the water to heat can be computed by a heat balance on the designed system . So we have:
PAD * (* PCIL (Tvap-Tcond) + latent heat + PAD * (Tcond-T) = mwat cpvap * * (T-Tinit)
Where T is final temperature of the water to heat.
Using a heat exchanger, regardless of being closed or open, in addition to imposing a cost for purchase and installation, reduces the capability of your steam to produce work.
Thanks All, I got the point tho, its feasible thermodynamically cause I regard mass balance and dirst and second law balances for this mixing component. So, regardless of cost, complexity and whatever from a project manager pint of view, it looks fine on paper through thermodynamics and heat transfer. And , this is an academic study for heat recovery unit in a wood factory out of corresponding ORC connected to a biomass system.
Thakns all for your informative comments, I learned alot.
All the best
Reza
Thanks Pouria, like always you point out every detail aspects of problem. I appreciate your time.
No problem with injection steam to heat up the water. You need just energy balance as mentioned above to make the caculation needed.
Best wishes Reza
Since there is a direct contact of liquid water and steam, you will end up with a saturated mixture of liquid and steam
It may work to serve its purposes (well, increasing the temperature), but superheated steam needs a lot efforts to produce. Not likely to be economically viable in most cases anyway.
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