Chemical Engineering Quiz

Course Expectations

• Students will understand chemical processes.
• Students will understand major constituents used in selected product manufacturing.
• Students will complete practicals on manufacturing selected products.

Roles of a Chemist

• Chemists can work in government agencies and departments.
• Chemists can work in research and development institutions.
• Chemists can work in biotechnology related fields.
• Chemists can work in quality control roles.
• Chemists can work in production and manufacturing.
• Chemists can work in water purification and effluent management.

Chemists vs. Chemical Engineers

• Chemists design chemical reaction pathways from raw materials.
• Chemists work in laboratories on a gram to kilogram scale.
• Chemical engineers scale up chemist's processes to mass produce a product.
• Chemical engineers work in chemical plants to produce materials in tons and beyond.

Chemical Industry

• The chemical industry manufactures industrial chemicals.
• The industry converts raw materials (oil, natural gas, air, water, metals, minerals) into over 70,000 products.
• Polymers and plastics account for approximately 80% of the industry's worldwide output.
• Chemicals are integral parts of consumer goods.

Chemical Industries in Nigeria

• Chemical industries rely on raw materials.
• Chemical industries require energy.
• Chemical industries require water.
• Chemical industries require machinery.
• Chemical industries require labor.
• Chemical industries require transportation for raw materials and finished goods.

Importance of the Chemical Industry

• The industry provides farmers with essential pesticides and fertilizers.
• The industry produces fibers and dyes used in textiles.
• The industry is essential for pharmaceutical and healthcare products.
• The industry produces polymers and plastics, examples include PVC piping, water tanks, wiring.

Chemical Products

• Chemical products are crucial for modern living standards.
• Chemical products support almost every aspect of daily life.
• Chemical products can be categorized into three broad classes.

Classification of Chemicals

• Commodity/bulk chemicals are produced in large quantities based on composition, purity, and price (examples: sulfuric acid, nitrogen, oxygen, chlorine).
• Fine chemicals are produced in small volumes and sold based on composition, purity, and price (examples: dimethylformamide, ion exchange resins).
• Specialty/functional chemicals are purchased for their effect (function) rather than chemical makeup (examples: coatings, adhesives, pharmaceuticals, pesticides, cosmetics, disinfectants).

Fine vs Bulk Chemicals

Fine vs Bulk Chemicals (Cont.)

Chemical Processes

• Chemical processes involve converting starting materials into desired products using specific systems, equipment, and conditions.
• A typical chemical process comprises three key steps.
• Transfer reactants to the reaction zone.
• Carry out chemical reactions using various unit processes.
• Separate products from the reaction zone using unit operations.

Additional Chemical Process Components

• Preparation and synthesis of feedstock
• Separation of products
• Monitoring product purity
• Handling byproducts/waste

Processes Involving Systems

• Chemical processes can include homogeneous systems
• Chemical processes can include heterogeneous systems

Chemical Process Flow Diagram (Figure)

• The image shows a flowchart of chemical process stages, including raw material storage, feed preparation, reaction, product separation, product purification, product storage, and sales. It also includes recycling of unreacted material and byproduct management

Separation and Purification Processes

• Separation/purification processes are used to isolate and purify target chemical products from other materials.
• Differences in material properties (e.g., boiling point, freezing point, particle size, phase affinity, density) guide separation process selection.
• Key factors for selecting a separation/purification method include material quantity, separation rate, feasibility, economics, quality, and operating mode.

Mass Balance

• Mass balance quantitatively describes the flow of materials into, out of, and within a defined system (e.g., a chemical reactor) over time.
• The Law of Conservation of Mass guides mass balance calculations.

Material Balance Equation

• Rate of accumulation of mass in the system = Inflow rate - Outflow rate + Generation rate - Consumption rate

Mass Balance Terms

• Input: Materials entering the system.
• Output: Materials leaving the system.
• Generation: Materials created within the system.
• Consumption: Materials consumed within the system
• Accumulation: Change in material within the system over time.

Mass Balance Applications

• Mass balances are essential in environmental engineering (e.g., water/wastewater treatment) to evaluate performance.
• Mass balances analyze the environmental response to inputs, monitoring process efficiency and process design.
• Mass balances support process design calculations to optimize sizing, determine the number and type of equipment needed.

Process Terms

• Steady state: Process variables don't change over time.
• Non-steady state: Process variables change over time.
• Process variables: Include flow rate, composition, temperature, concentration, and pressure.

Molar Units

• A mole is the molecular weight of a substance expressed in grams.
• Calculate molecular weight by summing individual atomic weights of the atoms in a substance's formula.
• Conversion from moles to grams: multiply by molecular weight.
• Conversion from grams to moles: divide by molecular weight.
• Mole fraction; moles divided by total moles.
• Mole % is mole fraction multiplied by 100

Sample Problem: Basic Calculation

• A 200 kg solution with 40% methanol and 100 kg of a 70% methanol solution are mixed to get a 300 kg resultant solution which comprises 150kg of methanol (80 + 70) and 150kg of water.
• Calculating the percentage of methanol in the final solution by using the formula; Final methanol composition = (150 / 300) * 100 = 50%

The Question and Solution (Chemical Reaction Problem)

• Diethyl ether, a medical anesthetic, is prepared from ethyl alcohol with acid.
• From 40.0 g of ethyl alcohol, calculate the grams of diethyl ether obtained, given a yield of 87%.
• Using the provided chemical equation and stoichiometric calculations, work through to calculate the final amount of ether (2C₂H₆O → C₄H₁₀O + H₂O)

Types of Processes

• Processes can be of various types, each with its own specific characteristics; batch versus continuous processes in the chemical process industry.

Chemical Industry Sectors

• The chemical industry comprises various sectors, each with unique characteristics (e.g., pharmaceuticals, pesticides, fertilizers, and petrochemicals).
• Product type determines the characteristics of the process.

Batch Process

• Batch processes occur in distinct stages.
• Materials are added to a vessel for the process cycle.
• Material doesn't flow in, out or within during the cycle
• Repeated batch cycles produce products.

Batch Process Benefits

• Ideal for small-scale production.
• Adaptable to accommodate formula or product changes.
• Direct scalability from lab experiments.

Continuous Process

• Ongoing material flow and output generation
• Materials are continuously entering and exiting
• Flow and outputs happen in sequence
• Example: Liquid pumping into a distillation column at a fixed rate.

Chemical Synthesis

• Synthetic organic chemicals result from converting carbonaceous feedstock into functionalized molecules.
• This is facilitated by one or more chemical reactions.
• Examples: various plastics, levelling agents for paints and preservatives for food.

Raw Materials for Chemical Industries

• Chemical industries rely on a variety of raw materials.
• Petroleum and natural gas are primary raw materials
• Biomass conversion for raw materials is of increasing importance.
• Over 90% of organic chemicals come from petroleum or natural gas.

Primary Raw Materials

• These are naturally occurring substances (e.g., grains, wood, honey, crude oil) that haven't undergone significant chemical changes during collection.

Secondary Intermediates

• Secondary intermediates are products further processed from primary materials.
• These include monomers (building blocks for polymers), such as caprolactam, and certain key chemicals specific for the synthesis of fibers (such as clothing) and other products, such as pesticides

Chemical Feedstocks

• The five major feedstock types are light olefins (ethylene and propylene), aromatics (benzene, toluene, xylene), hydrocarbons (butane, butene), kerosene-derived paraffins (C₉–C₁₇), and synthesis gas (mixture of carbon monoxide and hydrogen)

Fermentation (Overview)

• Fermentation is an enzymatic process for transforming organic compounds into simpler substances.
• Enzymes are complex organic compounds that catalyze biological processes.
• Microorganisms (e.g., yeast, bacteria) create these enzymes.

Fermentation History

• Louis Pasteur coined the term “fermentation” to denote the bubbling of sugar solutions.
• Liebig viewed fermentation as a complex process caused by nitrogen-containing substances found in microorganisms.
• E. Buchner’s 1896 work highlighted zymase enzymes, which are present in yeast and create alcohol from sugar.

What is Fermentation?

• Fermentation is a biochemical process that changes organic compounds into simpler substances.
• Fermentation often involves carbohydrate conversion into various products (alcohols, acids).
• It is used for food preservation (e.g., yogurt, pickled foods).
• A desired chemical product is the ultimate goal.

Enzyme Characteristics

• Enzymes are catalysts; they speed up chemical reactions without being consumed.
• Enzymes act on specific substrates (reactants).
• Enzyme activity is optimal at specific temperatures and pH.
• Enzymes can be destroyed under certain conditions, such as heat or UV light.
• Enzymes facilitate oxidation, reduction, and hydrolysis processes.

Enzyme Examples

• Diastase (malt or liver extract)
• Catalase (found in blood)
• Zymase (yeast extract)
• Urease (soybean extract)
• Lacti bacilli (curd-making bacteria)

Fermentation Benefits

• Fermentation enriches food's nutritional, digestible, and flavorful properties.
• Consuming fermented foods can improve digestion by assisting with intestinal bacteria.
• Fermented foods may offer anticancer effects and boost the immune system.

Fermentation Applications beyond Food

• Production of methane from sewage and sediments.

Fermentation Conditions

• Temperature
• Aeration
• Concentration
• Presence of other chemical substances
• Presence/absence of preservatives

Alcohol production

• Alcohol is produced in fermentation process that turns starch to certain sugars and then turns certain sugars into ethanol by the actions of yeast.

Alcoholic Beverages

• Alcohol beverages contain ethanol/alcohol (3%-60%).
• Classified into beer, wine, and spirits.

Beer Production

• Beer production entails the saccharification of starches and the subsequent fermentation of sugars using malted cereal grains.
• The fermentation process uses yeast to produce alcohol (typically 4%-6% ABV).
• Hops provide flavor and act as a preservative.

Industrial Beer Production

• Beer is a malt beverage produced using a yeast fermentation process.
• Microbiological activity (flavor, aroma, clarity, foam) is key to this fermentation process.
• Two main beer types, based on fermentation differences: bottom-fermented (lager) and top-fermented (ale).

Beer Production Process Steps

• Microorganisms: Selected yeasts are used (e.g., Saccharomyces cerevisiae, Saccharomyces carlsbergensis)
• Medium Ingredients: Primary raw materials like barley grains are key, and malted grains create the enzymes needed in the wort.
• Wort preparation: Malted grains/adjuncts are cooked, mixed with water, and mashed to activate enzymes.
• Mashing: process for enzymatic conversion of starch to fermentable sugars using certain temps (65°C)
• Separation: Fermentation medium separated from undissolved solids, then further processed through the hop filtration.
• Cooking/Boiling: Wort heated with hops for 1.5-2.5 hours in a brew kettle.
• Fermentation: Cooled wort is fermented by yeast, creating (ethanol and carbon dioxide)
• Maturation: Cooled and stored to allow the beer to settle.
• Carbonation: Carbon dioxide is added.
• Packaging: Sterilization occurs for bottle/can beers

Cold Storage Maturation

• Fermented beer (wort) is transferred to a storage tank.
• It is held at 0-3°C for a defined time.
• This process aids in settling solids and produces flavors within.

Beer Carbonation and Packaging

• Carbonation involves injecting carbon dioxide to remove dissolved oxygen.
• Packaging uses filtration (e.g., diatomaceous earth) before bottling/canning.

Beer Packaging

• Packaging prevents oxidation and extends storage life.
• Pasteurization (for bottles/cans) is common to extend the storage life.
• Chemical sterilization n-heptyl-p-hydroxybenzoate is occasionally used at 12 ppm for flavor preservation.
• Sterile packaging processes are used for beer production.

Further Notes, Recap, Exam Prep

• All statements, in this document regarding expected outcomes, and procedures, are for educational purposes only.

Test your knowledge on key concepts in chemical engineering, including mole percentages, reaction yields, and industrial processes. This quiz covers various fundamental aspects of chemical reactions and manufacturing processes. Perfect for students and professionals in the field seeking to reinforce their understanding.