Energy Efficiency tip of the day (Efficient Steam system control)
It depends on the proper pressure, temperature and flow control for all the steam system parts.
31. Efficient Steam system control
The Problem
Area
Flow control
Problem
No Steam flow-meters at production and
consumer side
Existing flow meters are not
calibrated regularly
Impact
missing of important data
needed for
Plant Efficiency
Energy Efficiency
Process Control
Costing and Custody Transfer
Solution Use steam flow meters when it is feasible you can only control what you can measure
Pressure control
At generation side (boiler side)
Problem Producing steam at lower pressure
Impact
Poor boiler efficiency
High steam consumption
High fuel consumption
At consumer side
Problem Unstable pressure (poor control)
Impact Performance fluctuation
Solution
At boiler side generate steam at maximum pressure accepted
At consumer side use suitable letdown valves
Direct Acting Control Valves
Pilot Operated Valves
Pneumatically Operated Valves
Temperature control
Problem Poor inlet steam control
Impact
Performance fluctuation
overheating or discomfort for
application
Mechanical damage
Loss of efficiency
Solution use suitable temp. control valve
Manual Control Valves
Self Acting Control Valves
Pilot Operated Valves
Pneumatically Operated Valves
Condensate removal
Problem
Poor steam traps
performance
Impact
Performance fluctuation
water logging
Loss of efficiency
water hammer and vibration
Solution Consider the following aspects in selection
The differential pressure
The size of the discharge orifice
The condensate temperature
Common result High operational and maintenance cost
Solution Proposed Actions
Check the existing steam flow meters and prepare a list of needed flow meters
Prepare a calibration plan for the existing steam meters once every 6 months if
possible.
Increase boiler pressure close to boiler design pressure and adjust
steam pressure at consumer side with letdown valve
Apply regular functional steam traps maintennce program
Check feasibility of using letdown or extraction turbine instead of
letdown valves to recover the energy
Check the existing steam inlet temperature trend for steam consumers
and evaluate your current temp. control system performance.
Check the existing steam inlet pressure trend for steam consumers and
evaluate your current pressure control system performance.
360 Proactive Engineer
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