Mod-01 Lec-02 Mass balance, Heat Balance, flow sheet

Understanding Mass and Heat Balance in Unit Operations

Introduction to Mass Balance

• The concept of mass balance is introduced, emphasizing that the quantity of liquids flowing in must equal the quantity flowing out under steady-state conditions.

• Example provided: In a distillation column with two feeds, one can calculate the flow rates of outgoing liquids based on incoming streams.

• A mass balance can also be performed for specific species (e.g., acetic acid), ensuring that the amount entering equals the amount leaving, assuming no conversion or loss occurs.

Steady State vs. Unsteady State

• Mass balances are applicable at steady state; during unsteady state conditions, accumulation may occur, leading to mismatched numbers.

Introduction to Heat Balance

• Heat balance involves accounting for heat input, output, generation within the unit, and losses to surroundings.

• Each fluid's heat content is calculated using its mass flow rate multiplied by specific heat and temperature change (ΔT).

Calculating Heat Content

• The formula for calculating heat content includes mass flow rate, density, specific heat capacity, and temperature correction.

• Different sources of heat include exothermic reactions or cooling processes; all these factors must be balanced.

Performing Heat Balance Calculations

• To perform a heat balance calculation: sum all input heats (including generated heat) and set them equal to total output heats (including lost heat).

• Understanding how much coolant is needed or how much energy is required for heating processes relies heavily on accurate heat balance calculations.

Application in Downstream Processes

• Both mass and heat balances are crucial in designing downstream units to identify potential losses in mass or energy requirements.

Case Study: Ethanol Production from Sugar Fermentation

• Overview of ethanol production using sugar fermentation; yeast strains like Saccharomyces cerevisiae are commonly used.

Ethanol Production and Its Challenges

Ethanol Fermentation Process

• Ethanol fermentation typically results in a dilute product, with only 10% ethanol concentration, as the remaining 90% consists of water, biomass, dead cells, debris, and salts.

• Thermophilic organisms used in fermentation can tolerate higher temperatures (50-60°C) and have been genetically modified for better ethanol tolerance. The fermentation process lasts about 40 hours.

• Post-fermentation, ethanol must be purified to around 95%, requiring extensive distillation processes that initially raise concentrations from 10% to approximately 30-40%.

• Achieving over 89% ethanol purity necessitates isotropic separation techniques due to the formation of an azeotropic mixture with water; this often involves adding a third component or absorbent.

• After distillation, biomass is filtered and dried for use as animal feed. This downstream process includes various units like distillation columns and filtration systems.

Companies Involved in Ethanol Production

• As of 2007 data, notable companies include Archer Daniels (1.07 billion gallons/year), Sun Energy Systems (120 million gallons/year), New Energy Cooperation (102 million gallons/year), and Hawkeye Renewables (100 million gallons/year).

• Ethanol serves multiple purposes: industrial applications, consumption as alcohol, and more.

Amino Acids: A Multi-Billion Dollar Industry

Overview of Amino Acid Production

• Amino acids are crucial in various sectors including animal feed, flavor enhancement, medical products, food additives, and energy processes.

• Key amino acids such as lysine and methionine are produced through fermentation while others like L-aspartic acid are synthesized chemically or via enzymatic methods.

Market Dynamics

• Major producers of amino acids include Japan, the US, South Korea, China, and Europe; the market is expected to grow at an annual rate of about 2.5%.

Cost Structure in Amino Acid Production

• Raw materials account for the largest portion of production costs (67%), followed by ammonium hydroxide usage (12%) for ion exchange columns.

Hardware Costs Breakdown

Cost Optimization in Amino Acid Production

Media and Raw Material Costs

• 95% of the raw material cost for L-phenylalanine production is attributed to the media, highlighting the importance of optimizing media to reduce operating costs.

• For L-leucine and L-lysine, 67% of costs are also due to nutrient media; thus, focusing on optimizing nutrient sources can significantly impact overall expenses.

Equipment Costs Breakdown

• In manufacturing L-leucine and L-lysine, equipment costs are distributed as follows: 33% reactors, 28% crystallizers, 19% storage tanks, 12% filters, and 7% ion exchange. Reducing reactor numbers can lower these costs.

• For aspartic acid and phenylalanine production, reactors account for 31%, crystallizers for 21%, storage tanks for 19%, and filters for 12%. Optimizing sizes of these components can lead to substantial savings.

Downstream Processing Techniques

• Recovery of amino acids from broth involves several downstream steps including reverse osmosis and chromatography. Each method will be discussed in detail in future classes.

Acetic Acid Production Methods

Applications of Acetic Acid

• Acetic acid is crucial in producing polyethylene terephthalate (PET), used widely in soft drink bottles, cellulose acetate for photographic film, and polyvinyl acetate used in glues.

Manufacturing Routes

• Acetic acid can be produced via synthetic routes or bacterial fermentation. Vinegar represents about 10% of global acetic acid production through biological methods.

Chemical vs Biological Production

• The chemical route primarily uses methanol carbonylation to produce acetic acid. In contrast, vinegar must be made biologically due to food purity laws.

Bacterial Fermentation Process

• The biochemical route employs bacteria like Acetobacter or certain Clostridium species that convert sugars directly into acetic acid without needing ethanol as an intermediate.

Downstream Processing Steps for Acetic Acid

• After acetic acid production:

• Filtration removes biomass and solids,

• Electro dialysis neutralizes salts,

Acetic Acid and 2,3 Butanediol Production Techniques

Distillation Methods for Acetic Acid Separation

• Various distillation methods can be employed to separate acetic acid from water, including fractional distillation, isotropic distillation, and extractive distillation.

• Absorption techniques can also be utilized; for instance, carbon can absorb acetic acid. Each method has its advantages and disadvantages, influenced by cost factors that vary with scale.

Overview of Acetic Acid Manufacturing Process

• A typical flow sheet for acetic acid production includes fermentation followed by multiple solvent extractions and distillations to yield pure acetic acid.

• The manufacturing plant layout is crucial in understanding the process flow from fermentation to final product extraction.

Introduction to 2,3 Butanediol

• 2,3 Butanediol serves as a valuable fuel additive and finds applications in printing inks, perfumes, moisturizing agents, plasticizers in explosives, and pharmaceuticals.

• The preferred microorganism for producing 2,3 Butanediol can utilize various sugars (hexoses, pentoses), but ethanol tolerance is critical due to the toxicity of butanediol itself.

Extraction Techniques for 2,3 Butanediol

• Several solvents are used for extracting butanediol post-fermentation; these include n-decanol and dibutyl phthalate. The choice of solvent affects extraction efficiency based on operating conditions.

• Due to butanediol's high boiling point, traditional distillation methods are ineffective; thus extraction becomes essential after fermentation.

Counter Current Extraction Methodology

• In counter current extraction processes like using n-decanol or oleyl alcohol in Karr extraction columns, the broth flows in one direction while the solvent flows oppositely to maximize contact.

• Salting out techniques using potassium carbonate can precipitate butanediol based on solubility changes during processing.

Downstream Processing Steps

• After fermentation and microfiltration to remove biomass, different approaches (extraction vs. salting out) dictate subsequent steps in processing butanediol.

• Solvent recovery through distillation allows for a closed-loop system where solvents are reused efficiently within the process.

Waste Management Considerations

• Both extraction methods generate waste materials that must be managed effectively; this includes solids or unwanted metabolites produced during processing.

Global Manufacturing Landscape

Antibiotics and Biodiesel Production

Antibiotic: Streptomycin

• Streptomycin, derived from Streptomyces griseus, was introduced nearly 20 years ago as a primary treatment for tuberculosis. It functions by damaging bacterial cell membranes and inhibiting protein synthesis through binding to the 16S rRNA of the bacterial ribosome.

• Major pharmaceutical companies like Merck, Ranbaxy Labs, Pfizer, GlaxoSmithKline, and Novartis manufacture streptomycin due to its ongoing relevance in treating tuberculosis.

• The production process involves several downstream steps: clarification of culture filtrate to remove flocculants via pH adjustment and carbon absorption, followed by multiple extractions at neutral pH.

• After extraction, crude streptomycin chloride is precipitated with ether; water removal is crucial to avoid sticky residues. Purification using ether ensures product quality.

• Product purity is critical for drugs like streptomycin as they must meet FDA regulations regarding safety and efficacy before human consumption.

Biodiesel Production

• Biodiesel serves as a sustainable alternative fuel for diesel engines, produced from vegetable oils. Its development has gained global interest due to environmental benefits.

• The biodiesel manufacturing process involves transesterification—reacting vegetable oil (triglycerides) with methanol in the presence of a strong base catalyst (e.g., sodium or potassium hydroxide).

• This reaction reduces the viscosity of vegetable oil by producing methyl esters, allowing it to be blended with conventional diesel fuels.

• A chemical reactor facilitates this process at temperatures around 60–70 degrees Celsius over approximately one hour. It differs from biological reactors since it does not involve fermentation processes.

• Post-reaction separation occurs in a separator where glycerol, methanol, and biodiesel are isolated through distillation columns; drying removes residual water from biodiesel for final use.

Glycerol Utilization

• Glycerol is a significant byproduct of biodiesel production. Research focuses on converting glycerol into value-added products due to anticipated surplus production leading to lower raw material costs.

Human Insulin Production

Cell Harvesting and Protein Purification Processes

Overview of Cell Processing

• The process involves two main steps: cell harvesting and cell disruption, which are essential for obtaining intracellular products like insulin.

• Enzymatic reactions are crucial for converting unfolded proteins into active insulin, emphasizing the importance of protein refolding in achieving desired functionality.

Manufacturing Cost Breakdown

• A significant portion of manufacturing costs is attributed to raw materials (50%), equipment (70%), and consumables (13%).

• Downstream processing accounts for nearly 30% of equipment costs in human insulin production, highlighting potential savings through optimization.

Steps in Insulin Production

• The purification step is critical after cell disruption; it involves removing impurities to ensure product quality.

• Stringent regulations govern the purity of pharmaceutical products, necessitating extensive purification efforts that contribute to 30% of overall production costs.

Insights on Biological Products

• Different biological products require tailored downstream processes based on their stability and specific requirements.

• Understanding the contribution of each unit operation to total manufacturing cost can guide research and development efforts aimed at cost reduction.

Considerations for Protein Purification

• Proteins are sensitive biological molecules that can lose stability due to environmental factors; careful handling is essential during purification.

• The aims of protein purification must be clearly defined—whether for manufacturing or analytical purposes—as this influences methodology choices.

Key Factors in Protein Extraction

• Knowledge about the chemical and physical properties of proteins, including size and molecular weight, is vital for effective extraction procedures.

Protein Extraction and Storage Considerations

Importance of Standardization in Protein Handling

• The extraction procedure must be standardized to prevent protein denaturation, considering factors like pH, osmolarity, temperature, and the presence of inhibitors or toxic chemicals.

• Intermediate purification and final polishing procedures also require standardization to ensure consistent results in protein handling.

Optimal Storage Conditions for Proteins

• Different proteins have varying stability requirements; some may need high concentrations while others should avoid water entirely during storage.

• Common storage methods include using 50% glycerol or serum albumin, with temperatures often ranging from -70°C to -80°C for optimal preservation.

Minimizing Sample Handling

• It is advisable to store proteins in smaller quantities (e.g., 500 µL flasks instead of 100 mL flasks) to reduce the risk of denaturation through excessive handling.

• Reducing sample handling at each stage is crucial as repeated manipulation can lead to protein denaturation.

Caution with Additives

• The use of additives should be minimized or avoided altogether since they can be toxic and alter the protein's conformation and properties over time.

• If additives are necessary, it’s important to assess their long-term effects on protein activity.

Early Removal of Contaminants