Hardness of Water

Hardness of Water

• Hardness of water is categorized into two types: Temporary hardness and Permanent hardness
• Temporary hardness is due to the presence of bicarbonate salts of calcium and magnesium, which can be removed by boiling
• Permanent hardness is due to the presence of sulfate, chloride, and nitrate salts of calcium and magnesium, which cannot be removed by boiling
• The unit of hardness is measured in milligrams per liter (mg/L) or parts per million (ppm)
• EDTA (Ethylene Diamine Tetraacetic Acid) method is used to determine the hardness of water

Disadvantages of Hard Water

• Hard water causes Boiler troubles, including:
  • Scale formation, which reduces heat transfer and increases fuel consumption
  • Sludge formation, which reduces the boiler's efficiency
  • Caustic embrittlement, which leads to boiler failure
  • Priming and Foaming, which causes carryover of water into the steam
  • Boiler corrosion, which reduces the boiler's lifespan

Softening of Water

• Softening of water can be done through three methods:
  • Zeolite process, which involves exchanging sodium ions for calcium and magnesium ions
  • Ion exchange process, which involves exchanging hydrogen ions for calcium and magnesium ions
  • Reverse Osmosis (RO), which involves using a semi-permeable membrane to remove ions and minerals

Numerical Problems

• Calculations of hardness involve determining the concentration of calcium and magnesium ions in water
• Zeolite process problems involve calculating the amount of sodium ions required to remove a certain amount of calcium and magnesium ions

Water Hardness

• Hardness of water is of two types:
• Temporary hardness (Carbonate hardness)
• Permanent hardness (Non-carbonate hardness)

Unit of Hardness

• Unit of hardness is milligrams per liter (mg/L) or parts per million (ppm)

Determination of Hardness by EDTA Method

• EDTA (Ethylene Diamine Tetra Acetic acid) method is used to determine total hardness of water

Disadvantages of Hard Water

• Scale formation: Deposits of calcium carbonate, magnesium carbonate and calcium sulfate
• Sludge formation: Deposits of magnesium hydroxide, iron oxide and aluminum oxide
• Caustic embrittlement: Weakening of metal boilers due to high pH
• Priming and foaming: Formation of steam bubbles in boilers
• Boiler corrosion: Corrosion of boiler metal due to acidic nature of water

Water Softening Methods

Zeolite Process

• Softening of water using naturally occurring minerals called zeolites
• Zeolites remove calcium and magnesium ions from water, replacing them with sodium ions

Ion Exchange Process

• Softening of water by exchanging sodium ions for calcium and magnesium ions
• Resin is used to remove calcium and magnesium ions from water

Reverse Osmosis (RO)

• Softening of water by applying pressure to force water through a semi-permeable membrane
• Membrane removes impurities and ions from water, producing soft water

Hardness of Water

• Hardness of water is a measure of the amount of calcium and magnesium ions present in water.
• There are two types of hardness: Temporary hardness ( bicarbonate-based) and Permanent hardness (non-bicarbonate-based).

Unit of Hardness

• The unit of hardness is milligrams per liter (mg/L) or parts per million (ppm).
• It can also be expressed in terms of degree of hardness, with one degree of hardness equal to 10 mg/L of calcium oxide.

Determination of Hardness by EDTA Method

• EDTA (Ethylene Diamine Tetra Acetic acid) is used to complex with calcium and magnesium ions in water.
• The amount of EDTA required to complex with these ions is directly proportional to the hardness of water.

Disadvantages of Hard Water

• Hard water causes scaling in boilers, leading to reduced efficiency and increased fuel consumption.
• It also leads to sludge formation, caustic embrittlement, and corrosion in boilers.

Boiler Troubles

• Scale formation: Hard water leads to the formation of scales, which reduce heat transfer and increase pressure.
• Sludge formation: Hard water causes the formation of sludge, which can clog pipes and reduce boiler efficiency.
• Caustic embrittlement: Hard water can cause the formation of caustic soda, leading to embrittlement of boiler materials.
• Priming and Foaming: Hard water can cause priming and foaming, leading to carryover of water into steam.
• Boiler corrosion: Hard water can cause corrosion of boiler materials, leading to boiler failure.

Water Softening

• Zeolite process: Involves exchanging sodium ions for calcium and magnesium ions, making water soft.
• Ion exchange process: Involves exchanging sodium ions for calcium and magnesium ions, making water soft.
• Reverse Osmosis (RO): Involves using a semi-permeable membrane to remove ions from water, making it soft.

Numerical Problems

• Calculations of hardness involve determining the amount of calcium and magnesium ions present in water.
• Calculations of Zeolite process involve determining the amount of sodium ions required to exchange with calcium and magnesium ions.

Hardness of Water

• There are different types of hardness of water
• Unit of hardness is measured in mg/L or ppm (parts per million)
• Hardness of water can be determined by EDTA method

Disadvantages of Hard Water

• Causes boiler troubles: scale and sludge formation, caustic embritlement, priming and foaming, and boiler corrosion

Softening of Water

• Can be done by Zeolite process, Ion exchange process, and Reverse Osmosis (RO)
• Softening of water is necessary to prevent boiler troubles and damage to equipment

Numerical Problems

• Calculations of hardness and Zeolite process are important for water treatment and analysis
• Numerical problems can help understand the principles of water softening and treatment

Hardness of Water

• There are different types of hardness of water
• Unit of hardness is measured in mg/L or ppm (parts per million)
• Hardness of water can be determined by EDTA method

Disadvantages of Hard Water

• Causes boiler troubles: scale and sludge formation, caustic embritlement, priming and foaming, and boiler corrosion

Softening of Water

• Can be done by Zeolite process, Ion exchange process, and Reverse Osmosis (RO)
• Softening of water is necessary to prevent boiler troubles and damage to equipment

Numerical Problems

• Calculations of hardness and Zeolite process are important for water treatment and analysis
• Numerical problems can help understand the principles of water softening and treatment