- Temperature transmitters. Monitor the temperature of fluids passing through heat exchangers. …
- Pressure transmitters. Detect pressure drops between heat exchanger inlet and outlet.
- Flow Meters. Indicate decreases that may be caused by build-up of fouling material in pipes and plates.
How does fouling occur in heat exchanger?
Biological fouling is caused by
the growth of organisms
, such as algae, within the fluid that deposit onto the surfaces of the heat exchanger. … Corrosion fouling occurs when a layer of corrosion products builds up on the surfaces of the tube, forming an extra layer of material that often has thermal resistance.
How do you stop a fouling heat exchanger?
The best way to avoid particulate fouling is
to keep the cooling water clean and thereby prevent particles from entering the heat exchanger
. However, in all cooling systems, and especially when using open cooling systems (with cooling towers), there will always be particles present in the cooling water.
What are the different types of fouling in heat exchangers?
- Precipitation fouling. It is scale formation on heat transfer surface due to dissolved substances like CaCO, Caso, salts present in water result in precipitation fouling. …
- Particulate fouling. …
- Chemical reaction fouling. …
- Corrosion fouling. …
- Biological fouling. …
- Solidification fouling.
What is fouling in heat transfer?
Fouling is
the formation of unwanted material deposits on heat transfer surfaces during process heating and cooling
. It occurs in all industries and most heat exchanger designs, with impacts ranging from heat transfer degradation to flow resistance and pressure drops.
How often should a heat exchanger be cleaned?
The association recommends reducing fuel costs by regularly cleaning heat exchangers to prevent fouling, which is often caused by a dirty, malfunctioning burner. Inspect heat exchangers
at least once per year
and clean them when they look dirty. Inefficient heat exchange is caused by scale and sediment buildup.
What are fouling factors?
The fouling factor represents
the theoretical resistance to heat flow due to a build-up
of a layer of dirt or other fouling substance on the tube surfaces of the heat exchanger, but they are often overstated by the end user in an attempt to minimize the frequency of cleaning.
Why baffles are provided in heat exchanger?
The main roles of a baffle in a shell and tube heat exchanger are to:
Hold tubes in position (preventing sagging)
, both in production and operation. Prevent the effects of steam starvation, which is increased with both fluid velocity and the length of the exchanger. Direct shell-side fluid flow along tube field.
Which is not an example of heat exchanger?
6. Which of the following is not an example of
recuperators
type heat exchanger? Explanation: Recuperators are not used in chemical factories. 7.
How is NTU calculated in heat exchanger?
- Obtain Process Parameters. Get process stream mass flowrate (M), specific heat (Cp) and inlet temperature (T). …
- Calculate NTU and Q
Max
Number of transfer units ( NTU ) is calculated using following equation : NTU = U.A/ C
Min
… - Determine Effectiveness. …
- Calculate Outlet Temperature.
What is the fouling coefficient?
The fouling factor
represents the theoretical resistance to heat flow due to a build-up
of a layer of dirt or other fouling substance on the tube surfaces of the heat exchanger, but they are often overstated by the end user in an attempt to minimize the frequency of cleaning. …
What is NTU in heat exchanger and what it indicates?
The Number of Transfer Units (NTU) Method is
used to calculate the rate of heat transfer in heat exchangers
(especially counter current exchangers) when there is insufficient information to calculate the Log-Mean Temperature Difference (LMTD).
Can fouling factor be negative?
This can occur
when fouling rate is quantified by monitoring heat transfer
. Relatively small amounts of deposit can improve heat transfer, relative to clean surface, and give an appearance of “negative” fouling rate and negative total fouling amount.
What are the symptoms of a damaged heat exchanger?
- Strange smells. A malfunctioning heat exchanger will often create an unpleasant and strong odor that smells similar to formaldehyde.
- Soot Build-up. …
- Corrosion & Cracks. …
- Change in the flame appearance. …
- Audible Sounds. …
- Presence of Carbon Monoxide.
How long should a heat exchanger last?
In most cases, the heat exchanger determines how long your furnace will last. The heat exchanger is responsible for heating the air that circulates through your home in the winter. Heat exchangers usually last
about 15 years
. If you invest in maintenance, yours might even last 20.
What can I use to clean a heat exchanger?
RYDLYME
is the perfect heat exchanger cleaning chemical to circulate and remove mineral deposits from heat exchanger tubes! Heat exchanger cleaning is made easy with RYDLYME Biodegradable Descaler. Simply circulate RYDLYME through the heat exchanger tubes removing mineral and scale build up in a safe and timely manner.
