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Introduction to Process Technology Unit 4 Basic Physics Today’s Agenda • • • • • • • • • • What is Physics? Why is Physics Important to Proc Oper? Properties and Structure of Matter Types of Energy Temperature & Thermal Heat Transfer Physics Laws Flow Rates Force and Pressure Work and Mechanical Efficiencies Electricity What is Physics? • Physics is the study of matter and energy • Matter • Energy Why Physics is Important to Proc Techs & Engineers & Other Technicians • Explains the basic principles of the equipment they use on a day-to-day basis. Examples – • Allows them to understand the processes used to convert raw products to end products • Maintaining safe operations Why Physics is Important to Proc Techs • Allows them to understand how to troubleshoot the process or to identify a problem and then solve the problem • Allows them to understand how the process affects other processes downstream Matter and its States • • • • Solids Liquids Gases Plasma Conservation of Matter • Matter cannot be created or destroyed; only changed • Matter is considered to be indestructible Specific Properties of Matter • Mass • Weight • Volume Specific Properties of Matter (Continued) • Density • Specific Gravity Specific Properties of Matter (Continued) • • • • • Inertia Force Pressure Buoyancy Velocity Specific Properties of Matter (Continued) • • • • • • Porosity Elasticity Friction Viscosity Hardness Tenacity (tensile strength) Specific Properties of Matter (Continued) • • • • • • • • Ductility Malleability Conductivity Adhesion Surface Tension Capillary Action Temperature Cohesive Force Structure of Matter • Atoms – Protons – Neutrons – Electrons • Molecule Structure of Matter (Continued) • Atomic Number • Atomic Weight States of Energy • Potential • Kinetic Temperature and State Changes • Temperature • State Changes – – – – – – – Evaporation Boiling Melting Freezing Condensing Sublimation Deposition Temperature Scales • Fahrenheit • Celsius • Absolute Zero – Kelvin = oC + 273 – Rankine = oF + 460 Temperature (BTU) Transfer • British Thermal Unit (BTU) • Conduction • Convection • Radiation Boiling Point • The temperature of a liquid when its vapor pressure = the surrounding pressure • Increasing the pressure of a system increases boiling point and vice versa… that is why water boils at a lower temperature up in the mountains compared to the coast Vapor Pressure • Vapor pressure – A measure of a liquid’s volatility and tendency to form a vapor – A function of the physical and chemical properties of the liquid – At a given temperature, a substance with higher vapor pressure vaporizes more readily than a substance with a lower vapor pressure Relationship of Boiling Point/vapor pressure/ surrounding pressure • Liquids w/ High VP – Low BP • Liquids w/ Low VP – High BP • As surrounding Pressure increases, then boiling point of liquid increases Heat Rate Equation • Important for steam production, use • Heat Rate = steam flow x specific heat capacity of steam x change in temperature Thermal Efficiency • Applied to heat exchanger optimization • Efficiency = (temperature in – temperature out) temperature in Physics Laws • Governing Gases – – – – – – – – Boyle’s Law Charles’ Law Gay-Lussac’s Law Avogadro’s Law Combined Gas Law Ideal Gas Law Dalton’s Law • Governing Gases & Liquids - Bernoulli’s Law NASA Video NASA Video General Gas Law • P1V1 = P2V2 n1 T1 n2 T2 Tanker Implodes http://www.break.com/index/tanker -implodes.html Dalton’s Law of Partial Pressures Principles of Liquid Pressure • Liquid pressure is directly proportional to density of liquid • Liquid pressure is proportional to height (amount) of liquid • Liquid pressure is exerted in a perpendicular direction on the walls of vessel Principles of Liquid Pressure • Liquid pressure is exerted equality in all directions • Liquid pressure at the base of a tank in not affected by the size or shape of tank’ • Liquid pressure transmits applied force equally, without loss, inside an enclosed container Flow Rate • Flowrate = Volume Time Bernouli’s Principle • States that in a closed process with a constant flow rate: – Changes in fluid velocity (kinetic energy) decrease or increase pressure – Kinetic-energy and pressure-energy changes correspond to pipe-size changes – Pipe-diameter changes cause velocity changes – Pressure-energy, kinetic-energy (or fluid velocity), and pipe-diameter changes are related Bernoulli Principle Bernoulli’s Principle Fluid Flow • Laminar Flow • Turbulent Flow Laminar Flow Turbulent Flow Turbulent flow Reynolds Number (R) • Used to size pipe to ensure proper flow (either laminar or turbulent) R = (Fluid Velocity)(Inside Diameter of Pipe)(Fluid Density) Absolute Fluid Viscosity Flow of Solids • A variety of gases are used to transfer solids – Nitrogen (most common since inert), air, chlorine, and hydrogen – In proper combination, these allow solids to respond like fluids – Examples – plastics manufacture, catalytic cracking units, vacuum systems Measuring Heaviness • Baume Gravity – standard used by industrial manufacturers to measure nonhydrocarbon heaviness • API Gravity – measures heaviness of hydrocarbons Force and Pressure • Pressure = Force Area Gauge Measurements • Absolute Pressure = atmospheric + Gauge • Gauge pressure = anything above atmospheric – Gauge P = Absolute P – Atmospheric P • Vacuum = a pressure below atmospheric • Where atmospheric pressure = 14.7 psi = 760 mm Hg = 29.92 in Hg = 1 torr Work • Work = Force x Distance Mechanical Advantage • Mechanical Advantage = Resistance Effort or Work Out Work In MA > 1 is good… so the larger the MA the better Mechanical Advantage Moments • Inclined Plane and MA Length of plane Height of plane Mechanical Advantage & Efficiency Efficiency = Actual MA Ideal MA Efficiency can never be > 1 Electricity • Electric current – • Electricity – • Direct Current – – Example – battery • Alternating Current – – Example – power generating station Electricity • Ohm’s Law – relationship between current (A for amps), resistance (Ω for ohms), and electrical potential (voltage – v for volts) • Voltage = Resistance x Current