Remove Scale/Sediment from System Surfaces

Particularly in fan systems where the airflow has high concentration of particles and ionic constituents deposition of particles, and formation of scale, on surfaces is a common problem. This problem may be amplified in system where the physical (temperature, humidity) and chemical conditions (ionic concentrations) show high variations in different part of the system – such as the hot air circulation for raw material pre-heating in cement kilns. Other parts that are particularly susceptible to contaminant accumulation are finned heat exchangers and filters. Such deposit/scale formation increases air resistance and consequently pressure drop and thereby increases energy consumption of the fan system. In heat exchangers, fouling also interferes with heat transfer, which can compound an airflow problem by requiring more airflow to compensate for the reduction in heat exchanger effectiveness. Depending on the system design and complexity, and the severity of the deposit/scale formation, manual and automated (mechanical hammering units) deposit/scale removal systems or practices can be used and energy consumption can be reduced.

Development Status Products
Commercial

Remove Scale/Sediment from System SurfacesCosts & Benefits

Parent Process: Fan Systems
Energy Savings Potential

This measure is estimated to offer following improvement potentials (UNIDO, 2010):
• 2.5% for low efficiency base cases;
• 1.5% for medium efficiency bas cases;
• 0.5% for high efficiency base cases.

Electrical and primary energy savings potential of this technology for different countries is estimated as following (UNIDO, 2010):

  Final (GWh/y) Primary (TJ/y)
US 520 5711
Canada 95 1189
EU 367 3448
Thailand 51 516
Vietnam 23 334
brazil 94 1046
CO2 Emission Reduction Potential

Total emission reduction potential, as kt CO2/y for different countries are estimated as (UNIDO, 2010): 

US 313
Canada 48
EU 160
Thailand 26
Vietnam 11
brazil 14

Costs

Estimated typical capital costs of this measure for different system sizes (S) are:
• US $100  for S < 37 kW;
• US $110 for 37 kW < S < 75 kW;
• US $135 for 75 kW < S < 150 kW;
• US $580 for 150 kW < S < 375 kW;
• US $1090 for 375 kW < S < 745 kW; (UNIDO, 2010)

Cost of conserved energy, expressed as US $/MWh-saved, in different countries are estimated as following (UNIDO, 2010):

US 22.5
Canada 22.2
EU 25.8
Thailand 6.1
Vietnam 6.1
brazil 7.4

Remove Scale/Sediment from System Surfaces Publications

Page Number: 

24, 64-76

Page Number: 

31