What is boiler water carry over and how it is to be eliminated?

What is boiler water carry over and how it is to be eliminated?

Boiler water carry-over is the contamination of the steam with boiler-water solids. Bubbles or froth actually build up on the surface of the boiler water and pass out with the steam. This is called foaming and it is caused by high concentration of any solids in the boiler water.

What are the normal boiler water parameters?

Boiler Feedwater Feedwater chemistry parameters to be controlled include dissolved solids, pH, dissolved oxygen, hardness, suspended solids, total organic carbon (TOC), oil, chlorides, sulfides, alkalinity, and acid- or base-forming tendencies.

Why boiler drum silica increases after the boiler trips?

Due to silica content in the feed water goes to steam drum where separation of wet steam and water takes place and in this way silica content increased in Boiler drum.

What is boiler layup?

A steam boiler layup is a maintenance procedure that helps to prevent corrosion within the boiler on both the waterside and fireside when you plan to have the boiler out of operation for an extended period of time. There are two (2) types of boiler layup methods — a wet layup and a dry layup.

What are the different reasons of carry over in boiler?

What Causes Boiler Carryover?

• Improper boiler construction/ design.
• High water levels.
• Surge firing, on-off firing, or on-off feedwater addition.
• Running the boiler in excess of boiler steam capacity.
• Improper blowdown.

Why bottom blowdown is carried out?

Sludge concentration is typically the highest in bottom of the boiler, which is why the bottom blowdown is performed to get rid of sludge that precipitates during boiling. On the other hand, dissolved solid concentration is the highest at six to eight inches below the surface of the water.

What are the causes of carry over?

Mechanical causes of carryover include boiler design, high water level, firing method, and load characteristics. Chemical causes of carryover include high solids concentration (dissolved or suspended), excessive alkalinity, grease, oil, or other contamination.

What is the difference between dry lay-up and wet lay-up?

There are two specific types of lay-up procedures for operators: dry lay-ups and wet lay-ups. A dry lay-up is intended for a long term shutdown, while a wet lay-up allows operators to quickly put a boiler back into service if the need arises.

What is wet layup?

Wet Lay-up/Hand Lay-up Manufacturing Process for Composites. Simple, low cost, open mold fabrication process using liquid epoxy resin to position layers of laminations in a mold until desired shape/thickness is achieved.

What does a carryover mean?

transitive verb. 1a : to transfer (an amount) to the next column, page, or book relating to the same account. b : to hold over (something, such as goods) for another time or season. 2 : to deduct (a loss or an unused credit) from taxable income of a later period.

What is carryover and priming?

Carryover also known as priming is any solid, liquid or vaporous contaminant that leaves a boiler with the steam. In low/medium pressure boilers (<100 bar) entrained boiler water is the most common cause of steam contamination.

What is sludge blowdown?

Sludge Blowdown System: This system is designed to monitor the time the Clarifier is in use, i.e. when the pump that feeds the beginning of the gravity flow waste stream leading to the Clarifier, the timer is timing.

What is boiler blowdown rate?

Rate of blowdown is a rate normally expressed as a percentage of the water feed. In the case of boilers, rate of blowdown is the removal rate of water from a boiler. Its purpose is to control boiler water parameters within prescribed limits to minimize: Scale. Corrosion.

Which chemical is used in boiler lay-up with water?

Sodium hydroxide
During this period the boiler should be fired twice per month to bring the boiler water to 160 o F. This circulates the boiler water and improves corrosion protection. Two methods for chemical treatment of the boiler water during wet lay-up are recognized….Boiler Layup Procedures.