Heating Air with Steam: Efficiency and Options

In summary, the question is about determining the most efficient way to heat pressurized air with minimal pressure loss, given the availability of steam and electricity on site. The main options discussed are an air-steam heat exchanger and an electric coil type heater, with the main advantages of the steam heater being lower cost of ownership, no need for high voltage, and less controls needed. It is also suggested to insulate the steam pipes leading to the air heater and to consider controlling the heater outlet temperature.
  • #1
dyollnave
2
0
Hey everyone, I have a questions. I am trying to determine the most efficient way to heat pressurized air (35-40 psig, and a flow of 20-30 scfm) at an inlet temperature of 60F, to an exit temperature of 200F with minimal pressure lose. On site I have the availability of saturated steam at (50-80 psig, with a flow rate of 50lb/hr avg, 287 lb/hr max.), as well as electricity(up to 3-phase, 480v). What are the best options given the above information.

What are the advantages/disadvantages of a air-steam heat exchanger vs. an electric coil type heater.

Condensate trapping and drain are not an issue, as waste water disposal is already in place.

Thanks a bunch, I look forward to joining everyone on PF!
 
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  • #2
The air will be used to dry items further down the process line, not vented into a room.
 
  • #3
Maybe you checked this, but looking at your numbers, I back of envelope calculated that you have plenty of steam flow available. A small thermodynamic steam trap would also be fine.

Main advantage of steam heater is:

* cost of ownership (less than 10 lb/hr steam vs about a 1.5 kW heater),
* no need for high voltage (240/480 volt, 3 phase, 60 Hz),
* less controls (power must be cut if heater element surface temperature reaches HIGH alarm setpoint).

Of course, you will need to insulate your steam pipes leading to the air heater.

Are you going to control heater outlet temperature?
 

Related to Heating Air with Steam: Efficiency and Options

1. What is an air/steam heat exchanger?

An air/steam heat exchanger is a device used to transfer heat between a hot fluid, typically steam, and a cooler fluid, typically air. It is commonly used in industrial and commercial applications to heat or cool a space or process.

2. How does an air/steam heat exchanger work?

The heat exchanger works by allowing the hot fluid, steam, to flow through tubes while the cooler fluid, air, flows over the tubes. The heat from the steam transfers to the air, heating it, and the cooled steam condenses into water and is removed from the system. This process continues until the desired temperature is reached.

3. What are the benefits of using an air/steam heat exchanger?

There are several benefits to using an air/steam heat exchanger, including energy efficiency, cost-effectiveness, and versatility. It allows for the transfer of heat between two fluids without mixing them, which can be beneficial in certain processes. It also helps reduce energy costs as it utilizes waste heat from the steam to heat the air.

4. What are the different types of air/steam heat exchangers?

There are two main types of air/steam heat exchangers: parallel flow and counterflow. In a parallel flow heat exchanger, both fluids flow in the same direction, while in a counterflow heat exchanger, they flow in opposite directions. Other types include cross flow and plate heat exchangers, which have different designs and applications.

5. How do you maintain an air/steam heat exchanger?

Maintenance of an air/steam heat exchanger is essential to ensure its proper functioning and longevity. It is recommended to regularly clean the heat exchanger to remove any buildup of debris or scale that can decrease its efficiency. It is also crucial to inspect and repair any leaks or damaged parts to prevent any potential problems. Regular maintenance schedules should be followed to keep the heat exchanger in optimal condition.

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