Clayton-Power-Plant-Presentation

SECTION SEVEN Rapid Start-Up

Less than five minutes to a full head of steam. Due to their small mass of steel and water, Clayton Steam Generators are designed to be fired from a cold start to a full head of steam in less than five minutes. In contrast, fire-tube boilers generally require at least an hour before they are fully productive. Losses due to extended start-up times with fire-tube boilers vary depending on frequency of start-up, boiler size and steam system. A conservative calculation of this loss would be to estimate a 60-minute start-up at the beginning of a nine-hour day: 1 hour ÷ 9 hours = 11 % start-up loss Over a longer period of time, such as a year or even a month, it is clear that losses due to extended start-up times can amount to thousands of pounds.

In order to avoid long start-up periods each day, many operations keep their fire-tube boilers running at low levels throughout the night and bring them up to full fire each day. This also wastes fuel because of the dramatically decreased operating efficiency of the fire- tube boiler at lower firing levels. The unique design of the Clayton Steam Generator lends itself to rapid start-up for two basic reasons : 1) The smaller mass of steel and water heats up quickly and evenly, and 2) the forced flow through the monotube coil ensures controlled temperature gradients, even with sudden load changes. Moreover, the monotube coil design is extremely flexible and therefore is not vulnerable to damage because of sudden temperature changes brought on by rapid start- up.

STEAM GENERATOR DRUM TYPE BOILER

VARYING STEAM LOAD

100%

FUEL RATE

0

SHUT DOWN

START UP PERIOD

TIME OF DAY

COMPARISON FOR TYPICAL DAY'S OPERATION