Understanding Dissolved Solids in Chemistry

Questions and Answers

What is the purpose of the plate type heat exchanger in the cooling system?

To increase the pressure of the water

To remove excess heat from the water (correct)

To maintain the temperature of freshwater

To filter the seawater before use

Which circuit is used for low-temperature zone machinery?

Seawater cooling circuit

High-temperature circuit

Low-temperature circuit (correct)

Primary circulation circuit

What maintains the balance between low-temperature and high-temperature freshwater systems?

Freshwater generator

Chemical additives

Expansion tank (correct)

Electrical pumps

What is the most abundant dissolved solid in seawater?

Sodium chloride Signup and view all the answers

What is one of the components of the high-temperature circuit?

Main engine jacket water system Signup and view all the answers

How is the quality of water in the cooling system maintained?

By periodically adding chemicals Signup and view all the answers

What is the primary purpose of the marine engine cooling water system?

To remove unusable heat from machinery Signup and view all the answers

What system refills the expansion tank for low and high-temperature circuits?

Hydrophore system Signup and view all the answers

Which ion constitutes the largest percentage of solids present in seawater?

Chloride (Cl-) Signup and view all the answers

How much magnesium sulfate is found in one kilogram of seawater?

1.66 gm Signup and view all the answers

What typically circulates the HT cooling water system?

Electrical cooling water pumps Signup and view all the answers

What role does cooling water play in maintaining engine metals?

Helps metals retain mechanical properties Signup and view all the answers

What is a critical parameter to monitor to ensure cost-effective operation?

Quality of engine cooling water Signup and view all the answers

What percentage of total dissolved solids in seawater does magnesium chloride represent?

10% Signup and view all the answers

Which of the following salts is present in the largest amount in a freshwater sample?

Calcium Sulfate Signup and view all the answers

What is the primary cause of engine components overheating?

Burning fuel Signup and view all the answers

What is the primary quality required for cooling water in an engine?

Demineralized (distilled) water Signup and view all the answers

Why is untreated distilled water considered corrosive?

It absorbs carbon dioxide from the air. Signup and view all the answers

Which of the following is NOT a form of corrosion that can occur in cooling water systems?

Oxidation corrosion Signup and view all the answers

What can result from the products of corrosion in a cooling system?

Blocking of pathways Signup and view all the answers

What is the recommendation if distilled water is not available for cooling?

Use tap water after softening and treatment. Signup and view all the answers

What materials can contribute to scale formation in cooling systems?

Hard mineral coatings and sediments Signup and view all the answers

Which of the following cooling water sources is highly corrosive and not recommended?

Rainwater Signup and view all the answers

Which of the following is a key reason for adding a corrosion inhibitor to distilled water used as cooling water?

To prevent the absorption of CO2 Signup and view all the answers

What is the main purpose of using zinc in pipework?

To act as a sacrificial metal against corrosion Signup and view all the answers

What temperature range poses the highest risk of corrosion for zinc?

600C to 900C Signup and view all the answers

Why is galvanized piping not recommended for diesel cooling systems?

It can cause reverse polarity effects Signup and view all the answers

Which of the following is a property of sodium borate when used in cooling water treatment?

It acts as a fungicide Signup and view all the answers

Which corrosion inhibitor is specifically noted for its protective qualities for aluminum?

Sodium Nitrite Signup and view all the answers

What is the recommended dosage range for sodium benzoate in diesel cooling water treatment?

10000 to 15000 ppm Signup and view all the answers

What effect does a higher concentration of chlorides or sulfates have on corrosion inhibitors?

It increases the level of corrosion inhibitor necessary Signup and view all the answers

What type of metal is sodium chromate protective for in diesel cooling water systems?

Copper and copper alloys Signup and view all the answers

What is the first step to take if abnormal deposits or rust are detected in the cooling water system?

Clean the system thoroughly Signup and view all the answers

Which procedures are included in the cleaning of the cooling water system?

Degreasing and descaling Signup and view all the answers

Who should ideally perform the cleaning of the cooling water system?

A reliable specialist firm Signup and view all the answers

What should be done with the cooling water after the cleaning process?

Refill it with newly treated water Signup and view all the answers

What is a potential hazard related to the cleaning chemicals used in the cooling water system?

They can cause chemical burns Signup and view all the answers

What is an essential guideline to follow when cleaning the cooling water system?

Follow the supplier's instructions for cleaning chemicals Signup and view all the answers

What is an inappropriate reaction if rust or deposits are found in the cooling water system?

Ignore it until a leak occurs Signup and view all the answers

What is a critical aspect of cleaning the cooling water system?

Using special chemicals safely Signup and view all the answers

Study Notes

Composition of Seawater

Sodium chloride (NaCl) accounts for 79% of total dissolved solids, with a concentration of 25,000 PPM.
Magnesium chloride (MgCl2) contributes 10%, equating to 3,000 PPM.
Other significant salts include magnesium sulfate (MgSO4) at 6% (2,000 PPM), calcium sulfate (CaSO4) at 4% (1,200 PPM), and calcium bicarbonate (Ca(HCO3)2) at less than 1% (200 PPM).
Salts in 1 kilogram of seawater:
- Sodium chloride - 27.21 gm
- Magnesium chloride - 3.81 gm
- Magnesium sulfate - 1.66 gm
- Calcium sulfate - 1.26 gm
- Potassium sulfate - 0.8 gm
- Calcium carbonate - 0.12 gm
- Magnesium bromide - 0.08 gm

Freshwater Sample Analysis

Concentration of salts in freshwater:
- Sodium chloride (NaCl) - 50 PPM
- Sodium nitrate (NaNO3) - 35 PPM
- Magnesium sulfate (MgSO4) - 30 PPM
- Calcium sulfate (CaSO4) - 90 PPM
- Calcium carbonate (CaCO3) - 200 PPM

Major Ions in Seawater

Chloride (Cl-) - 55.03%
Sodium (Na+) - 30.59%
Sulfate (SO4-2) - 7.68%
Magnesium (Mg+2) - 3.68%
Calcium (Ca+2) - 1.18%
Potassium (K+) - 1.11%

Marine Engine Cooling Water

The cooling system is essential for removing excess heat from ship engines and machinery.
A cooling liquid circulates within the engine, absorbing heat and passing through a heat exchanger for cooling with seawater.
Freshwater is utilized to cool engine parts and is stored in a tank before cycling through a plate-type heat exchanger.

Low-Temperature and High-Temperature Circuits

Low-Temperature Circuit (L.T):
- Used for low-temperature equipment and connected to the seawater cooler.
- Maintained balance with the high-temperature circuit via a common expansion tank.
High-Temperature Circuit (H.T):
- Comprises the main engine's jacket water system, operating at high temperatures.
- Maintained by circulating low-temperature freshwater.

Chemical Properties of Engine Cooling Water

Regular chemical addition is essential to prevent corrosive conditions.
Critical parameters for monitoring: pH, hardness, conductivity, turbidity, phosphates, sulfates, ammonium, chlorides, calcium, magnesium, aluminum, iron, zinc, silicate, nitrate, nitrite, chemical oxygen demand, total organic carbon.

Quality Requirements for Cooling Water

Use demineralized (distilled) water for effective cooling and to prevent corrosion; corrosion inhibitors are critical due to the corrosive nature of untreated distilled water.
Tap water and rainwater are generally unsuitable; sea water is strictly prohibited due to high corrosion risks.

Corrosion and Scale Concerns

Corrosion can lead to severe issues such as pitting and scale formation, impacting heat transfer and cooling efficiency.
Scale consists of hard deposits formed from minerals and requires regular management.

Chemicals for Cooling Water Treatment

Sodium Nitrite: Corrosion inhibitor; dosage 1000 to 3000 PPM, protective to cast iron, steel, and aluminum.
Sodium Benzoate: Protective to steel and solder; dosage 10,000 to 15,000 PPM.
Sodium Borate: Buffers at pH 8.9; also a fungicide; dosage with other inhibitors 1000 to 3000 PPM.
Sodium Chromate: Effective for all pipes and alloys; dosage 1000 to 3000 PPM.

Cleaning Protocol for Cooling Water Systems

Abnormal deposits necessitate thorough cleaning, including degreasing and descaling.
Water testing is vital to determine the necessary concentration of inhibitors for effective operation.

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Description

This quiz explores the concepts of dissolved solids and their concentration in various chemical compounds. Test your knowledge on the specific percentages and PPM values of common salts and minerals in solutions. Perfect for students learning about solution chemistry and ionic compounds.