Air challenges steam for preoperational steam path cleaning

Journal Article · Tue Jan 01 04:00:00 EST 1991 · Power Engineering; (United States)

OSTI ID:5766145

Skrgic, P J ^[1]; Larson, L ^[2]; Brookins, C ^[3]; Pier, J B ^[4]

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1. Allegheny Power System (US)
2. Basin Electric (US)
3. Detroit Edison (US)
4. General Electric (US)

Compressed air blowing should be considered for cleaning a new generating unit's steam path. Compared to traditional steam blowing, it offers schedule flexibility and can reduce construction critical path time. Cleaning of the steam path piping prior to start-up is required to minimize the possibility of damage to the turbine by removing weld bead deposits, pipe slag and other foreign material that might otherwise be carried into the turbine. Steam path piping may include the boiler, superheater, reheater, main steam lines and hot and cold reheat lines. Preoperational cleaning of the steam path is an emotional subject. The bulk of steam path cleaning experience lies in steam blows utilizing the unit's steam generation system whether it has a large fired, utility boiler or an unfired, waste heat boiler operating on gas turbine exhaust gas. As a result, there is a large segment of expertise in this field that has never experienced anything other than steam as a cleaning medium. Since there is little challenge to the steam blow in most organizations, the question is why steam blow has had little rigorous analysis. The consensus answer has been that thermal cycling is necessary to ensure a clean system. This article documents 20 units between 13 MW and 700 MW that used compressed air to clean the steam path successfully based on the premise that momentum flow rate is the key pipe cleaning criterion. Compressed air temperatures were about 100 F, and boiler metal wall temperatures, when measured, did not change. The systems were not heated up and cooled down to obtain thermal cycling, nor were the steam lines chemically cleaned, yet the air blow results have been consistently rated as good as, or better than, steam blows.

• OSTI ID: 5766145
• Journal Information: Power Engineering; (United States), Journal Name: Power Engineering; (United States) Vol. 95:1; ISSN POENA; ISSN 0032-5961
• Country of Publication: United States
• Language: English

Related Subjects

20 FOSSIL-FUELED POWER PLANTS
200101 -- Fossil-Fueled Power Plants-- Cooling & Heat Transfer Equipment & Systems
200103* -- Fossil-Fueled Power Plants-- Waste-Fueled Systems
200105 -- Fossil-Fueled Power Plants-- Heat Utilization
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
320304 -- Energy Conservation
Consumption
& Utilization-- Industrial & Agricultural Processes-- Waste Heat Recovery & Utilization
AIR
BLOWERS
BOILER FUELS
BOILERS
CLEANING
COMPRESSED AIR
COMPRESSED GASES
EQUIPMENT
FLUIDS
FOULING
FUELS
GAS TURBINE POWER PLANTS
GAS TURBINES
GASES
MACHINERY
POWER PLANTS
STEAM GENERATORS
STEAM LINES
STEAM TURBINES
SUPERHEATERS
TURBINES
TURBOMACHINERY
VAPOR GENERATORS
WASTE HEAT BOILERS
WASTE HEAT UTILIZATION
WASTE PRODUCT UTILIZATION