The term "economy" in the context of environmental and water treatment refers to the efficient use of resources, primarily energy, to achieve the desired outcome. This is particularly important in processes like thermal desalination, where significant energy input is required to produce potable water.
Thermal desalination involves heating saltwater to evaporate the water, leaving behind salts and impurities. The evaporated water is then condensed and collected as freshwater. While this process effectively removes contaminants, it's energy-intensive, making energy efficiency a crucial factor for economic viability.
The economy of thermal desalination is often measured by the "thermal desalination economy," which is defined as the ratio of kilograms of distilled water produced per 2326 kJ of energy input. This metric represents the amount of freshwater produced for every unit of energy consumed.
Factors affecting thermal desalination economy:
Improving thermal desalination economy:
In conclusion, the "economy" in thermal desalination refers to the efficient use of energy to produce freshwater. By carefully considering the factors influencing the desalination economy, we can strive to improve energy efficiency and optimize water production for a more sustainable future.
Instructions: Choose the best answer for each question.
1. What does "economy" refer to in the context of environmental and water treatment? a) The cost of building and operating a desalination plant. b) The efficient use of resources, primarily energy. c) The amount of freshwater produced per day. d) The impact of desalination on the environment.
The correct answer is **b) The efficient use of resources, primarily energy.**
2. What is the main factor influencing the economic viability of thermal desalination? a) The availability of skilled labor. b) The price of freshwater in the market. c) The cost of building the desalination plant. d) Energy efficiency.
The correct answer is **d) Energy efficiency.**
3. Which metric is used to measure the "thermal desalination economy"? a) Kilograms of distilled water produced per hour. b) Kilograms of distilled water produced per 2326 kJ of energy input. c) Cost of producing one liter of freshwater. d) Percentage of salt removed from the seawater.
The correct answer is **b) Kilograms of distilled water produced per 2326 kJ of energy input.**
4. Which of the following is NOT a factor affecting the thermal desalination economy? a) Feedwater salinity. b) The type of desalination technology. c) The weather conditions at the plant location. d) Operating temperature and pressure.
The correct answer is **c) The weather conditions at the plant location.**
5. Which of these methods can improve the economy of thermal desalination? a) Increasing the operating pressure to speed up the process. b) Using only fossil fuels to power the desalination plant. c) Implementing heat recovery systems. d) Using only the cheapest desalination technology available.
The correct answer is **c) Implementing heat recovery systems.**
Scenario: A thermal desalination plant produces 1000 kg of distilled water per hour using 2,500,000 kJ of energy.
Task: 1. Calculate the thermal desalination economy for this plant. 2. Explain what the calculated value means in practical terms. 3. Suggest two ways to improve the economy of this plant based on the information provided.
**1. Calculation:** Thermal Desalination Economy = (Kilograms of distilled water produced) / (Energy input in kJ) Economy = 1000 kg / 2,500,000 kJ = 0.0004 kg/kJ **2. Interpretation:** This value means that for every 2326 kJ of energy input, the plant produces 0.9264 kg of freshwater (0.0004 kg/kJ * 2326 kJ = 0.9264 kg). **3. Suggestions for Improvement:** * **Reduce Energy Consumption:** The plant is using more energy than average for this output. Investigate potential for improving insulation to reduce heat loss, optimizing operating parameters (temperature, pressure, flow rates), or implementing more energy-efficient technologies. * **Increase Water Production:** Explore ways to increase the water production rate without increasing energy consumption. This could involve upgrading the existing technology or implementing a more efficient desalination process.
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