Podcast
Questions and Answers
Which of the following operations is least likely to be classified as a unit operation in chemical engineering?
Which of the following operations is least likely to be classified as a unit operation in chemical engineering?
- Agitation and mixing
- Retorting
- Heavy-fluid separation (correct)
- Classification
In metallurgy, particularly in the context of copper refining, what process involves heating ore to extract a metal?
In metallurgy, particularly in the context of copper refining, what process involves heating ore to extract a metal?
- Roasting
- Calcination
- Smelting (correct)
- Converting
Under standard temperature and pressure, what volume does one pound-mole (lb-mol) of an ideal gas occupy?
Under standard temperature and pressure, what volume does one pound-mole (lb-mol) of an ideal gas occupy?
- 359 ft³ (correct)
- 349 ft³
- 339 ft³
- 369 ft³
Which of the following ratios most accurately represents the stoichiometric composition of air by weight, considering only nitrogen and oxygen?
Which of the following ratios most accurately represents the stoichiometric composition of air by weight, considering only nitrogen and oxygen?
When calculating the heat of reaction with a reference temperature of 298 K, which thermodynamic law is directly applicable?
When calculating the heat of reaction with a reference temperature of 298 K, which thermodynamic law is directly applicable?
Which diagram visually represents material flow, where the width of each flow path corresponds to its quantity?
Which diagram visually represents material flow, where the width of each flow path corresponds to its quantity?
What is the typical value of sensible heat for an input material entering a system at a temperature below 298 K?
What is the typical value of sensible heat for an input material entering a system at a temperature below 298 K?
Which process is most directly associated with the initial production of crude oil and petroleum from hydrocarbon sources?
Which process is most directly associated with the initial production of crude oil and petroleum from hydrocarbon sources?
Which of the following is a primary advantage of using liquid fuels in industrial applications?
Which of the following is a primary advantage of using liquid fuels in industrial applications?
What is the correct sequence of transformation in the coalification process?
What is the correct sequence of transformation in the coalification process?
Which equipment is specifically designed to experimentally determine the gross calorific value (heating value) of a substance?
Which equipment is specifically designed to experimentally determine the gross calorific value (heating value) of a substance?
Which ASTM standard specifically addresses abrasion resistance testing for materials?
Which ASTM standard specifically addresses abrasion resistance testing for materials?
In the context of material testing, which ASTM standard is relevant to assessing breakage characteristics?
In the context of material testing, which ASTM standard is relevant to assessing breakage characteristics?
Which ASTM standard provides specifications and test methods related to porosity sufficiency in materials?
Which ASTM standard provides specifications and test methods related to porosity sufficiency in materials?
When considering gas production from coal, which gas is typically produced when the primary constraint is the limited availability of suitable coal?
When considering gas production from coal, which gas is typically produced when the primary constraint is the limited availability of suitable coal?
Which gas is produced through the reaction of steam with a hot bed of coal or coke?
Which gas is produced through the reaction of steam with a hot bed of coal or coke?
Which property is not considered directly indicative of fuel oil performance and quality?
Which property is not considered directly indicative of fuel oil performance and quality?
Within the context of combustion and flame studies, what term is synonymous with 'flame velocity'?
Within the context of combustion and flame studies, what term is synonymous with 'flame velocity'?
How are API gravity and specific gravity related in the context of characterizing fuel oils?
How are API gravity and specific gravity related in the context of characterizing fuel oils?
After coal is burned, which substance is least likely to be found among the resulting products?
After coal is burned, which substance is least likely to be found among the resulting products?
Flashcards
What is a unit operation?
What is a unit operation?
A fundamental operation in chemical engineering, examples include mixing, classification, distillation.
What is Calcination?
What is Calcination?
The process of heating ores to cause thermal decomposition of carbonates by heating in the absence of air.
What is smelting?
What is smelting?
A process involving heating ore to a high temperature to extract a base metal.
What is the equivalent value of 1 lb-mol for gases at STP?
What is the equivalent value of 1 lb-mol for gases at STP?
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What is the stoichiometric air ratio?
What is the stoichiometric air ratio?
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What is Hess's Law?
What is Hess's Law?
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What is a Sankey diagram?
What is a Sankey diagram?
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What is sensible heat at < 298K?
What is sensible heat at < 298K?
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What is distillation?
What is distillation?
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What is the advantage of liquid fuels?
What is the advantage of liquid fuels?
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What is coalification?
What is coalification?
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What is a bomb calorimeter?
What is a bomb calorimeter?
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Viscosity vs. Temperature?
Viscosity vs. Temperature?
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What is adiabatic flame temperature?
What is adiabatic flame temperature?
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What is smelting power?
What is smelting power?
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What is heat recuperator?
What is heat recuperator?
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What is Overall thermal efficiency?
What is Overall thermal efficiency?
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What does a low Biot number indicate?
What does a low Biot number indicate?
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What is thermal diffusivity?
What is thermal diffusivity?
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What does mass vs time indicate?
What does mass vs time indicate?
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Study Notes
- Unit operations are fundamental steps in chemical engineering processes; agitation and mixing, classification, retorting and heavy-fluid separation are types of unit operations.
- Refining metals, particularly copper, involves processes like calcination, roasting, smelting, and converting.
- The equivalent value of 1 lb-mol for gases at standard temperature and pressure is approximately 359 ft³.
- The stoichiometric air ratio by weight consists of approximately 76.7% nitrogen and 23.3% oxygen
- Hess' Law is used to calculate the heats of reaction when the reference temperature is at 298 K.
- A Sankey diagram visually represents the flow of material, with the width of each flow proportional to its quantity.
- Sensible heat of input material entering at less than 298 K is a positive value.
- To produce crude petroleum from hydrocarbons, distillation is essential.
- Using liquid fuel is advantageous because of ease of control and handling due to its flexibility plus ease of transport and storage
- The sequential process of coalification is: Wood → peat → lignite → bituminous → anthracite → graphite → diamond
- An oxygen bomb calorimeter is used to experimentally determine gross calorific power.
- ASTM D-3172-73 pertains to abrasion resistance, breakage and porosity sufficiency tests.
- Producer gas is produced when gas is needed but only coal is available.
- Water gas is produced by reacting steam with a hot bed of coal or coke.
- Solubility is not a fuel oil property.
- Flame velocity is also known as the rate of flame speed or rate of flame propagation.
- Degree API and specific gravity in fuel oils are inversely proportional.
- Ammonium sulfite and coal are not products of burned coal
- Critical process temperature is the minimum temperature at which slag flow is achieved for producing processes.
- There is an inverse relationship between viscosity and temperature in terms of heat utilization
- Adiabatic flame temperature is the temperature of combustion products when the reaction occurs without heat loss.
- Actual flame temperature makes up 48-75% of AFT.
- Smelting power, also known as GCV, is the maximum furnace capacity.
- Heat recuperators are specific equipment in which both fluids flow continuously through the system, separated only by walls enabling heat transfer.
- Overall thermal efficiency is the parameter where the sensible heat of pre-heated air is a fraction of the sensible heat of pre-heated air at the temperature of the flue gas and a fraction of the sensible heat of the flue gas at the same temperature.
- In the SFL, 99% of the fluid layer is stagnant.
- The Stefan-Boltzmann equation governs radiation.
- For gray bodies, absorptivity ε is equal to emission α, ε = α < 1
- Aluminum, calcium, magnesium, and antimony are medium melting point metals.
- In pyrometallurgical multi-phase systems, dross is the least dense material.
- Calcination remedies speiss prior to smelting.
- To produce liquid steel, phosphorus and sulfur should be contained to little to no amount at all.
- Silica content and viscosity are inversely proportional.
- Corrosion ensures compatibility between refractory and slag.
- Bisilicate has a silicate degree of M2O3-3SiO2.
- MnO, MgO, Al2O3, and CaO are basic compounds.
- Masonry construction utilizes a reverberatory furnace.
- Hearth furnaces belong to Class II.
- In induction furnaces, the coil is the part being heated, which then generates the melting of the material.
- Thermal gradient is the main cause of spalling.
- High duty bricks contain 75% alumina.
- Lime is the main refractory used to maintain the bottoms and banks of basic hearth furnaces.
- Thermal conductivity of carborundum is 10x higher than that of fireclay brick.
- Sodium silicate causes the development of bond in air-setting mortars.
- Slag contamination is a cause of over-loading in refractory failures.
- The coefficient in the calculation of the shape factor of an edge is 0.54.
- Color of the solid does not affect the rate of reaction in a solid-gas roasting process.
- The primary role of air in sulfide ore roasting is to be a source of oxygen for oxidation.
- If the Biot number (Bi) is much less than 0.1, temperature is uniform throughout the object and the Lumped Capacitance Method is valid.
- The Lumped Capacitance Method assumes a uniform temperature throughout the object when the Biot number is below 0.1.
- Thermal diffusivity (α) of a material is defined as α = k/(ρcp).
- In roasting experiments, if plotting Mass vs. Time gives a straight line with a high R² value, the reaction is zero-order.
- The Shrinking Core Model helps understand the rate-limiting step in leaching or roasting for solid-gas or solid-liquid reactions.
- A fan blowing air over a hot surface is an example of forced convection.
- In free convection, air or fluid moves naturally with no external force.
- Heisler's chart requires the Biot number and Fourier number to analyze transient heat conduction.
- If a material has a Biot number less than 0.1, the temperature is mostly uniform because internal resistance is small compared to surface resistance.
- The slope equals -hA/(pcpV), which calculates the heat transfer coefficient h when plotting ln(T-T∞)/(T₀-T∞) vs. time.
- Calcination decomposes carbonates by heating in the absence of air.
- Based on a graph of ΔG vs. Temperature, ΔH can be determined from slope and ΔS from intercept.
- A linear decrease in mass vs. time indicates the reaction is zero-order.
- During the calcination of calcium carbonate (CaCO3), it decomposes into calcium oxide (CaO) and releases carbon dioxide (CO2) gas.
- After complete calcination of 2 g of pure CaCO3, the theoretical mass of CaO produced is 1.12 g.
- If 1 g of CaCO3 results in 0.65 g of product after calcination, then transformed CaCO3 = 75%.
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