Unit Operations of Chemical Engineering

Citation

McCabe, W. L., Smith, J. C., & Harriott, P. (2005). Unit Operations of Chemical Engineering (7th ed.). McGraw-Hill.

Chapter Summary

The seventh edition has 29 chapters in five sections, followed by 19 appendices of conversion factors, dimensionless groups, equipment data and physical-property tables. The preface describes it as an introductory text for junior or senior undergraduates, with a separate chapter for each principal unit operation. It assumes the usual mathematics, chemistry and physics courses, an introduction to chemical engineering, and an elementary knowledge of material and energy balances.

Section 1, Chapter 1: Definitions and Principles

The single introductory chapter, covering definitions and principles. The preface adds that nearly all equations are written for SI units, although older cgs and fps units have not been removed entirely.

Section 2, Chapters 2–4: Fluid Statics and Its Applications; Fluid Flow Phenomena; Basic Equations of Fluid Flow

The fluid mechanics section begins with fluid statics, then fluid flow phenomena and the basic equations of fluid flow. According to the publisher's list of changes, the viscosity discussion in Chapter 3 now includes simple theories for gases and liquids, and similar theories for thermal conductivity and diffusivity appear in later chapters so that the three can be compared.

Section 2, Chapters 5–9: Incompressible Flow in Pipes and Channels; Flow of Compressible Fluids; Flow past Immersed Objects; Transportation and Metering of Fluids; Agitation and Mixing of Liquids

These chapters apply the basic equations to pipes and channels, compressible fluids and flow around objects, then to pumping and flow measurement and to the agitation and mixing of liquids.

Section 3, Chapters 10–13: Heat Transfer by Conduction; Principles of Heat Flow in Fluids; Heat Transfer to Fluids without Phase Change; Heat Transfer to Fluids with Phase Change

The heat transfer section moves from conduction to heat flow in fluids, then to heat transfer to fluids without and with phase change.

Section 3, Chapters 14–16: Radiation Heat Transfer; Heat-Exchange Equipment; Evaporation

Radiation, the equipment in which heat is exchanged, and evaporation. The edition adds heat pipes and plate-type exchangers to the equipment chapter.

Section 4, Chapters 17–20: Principles of Diffusion and Mass Transfer between Phases; Gas Absorption; Humidification Operations; Equilibrium-Stage Operations

The mass transfer section opens with diffusion and transfer between phases, then applies it to gas absorption and humidification, and introduces equilibrium-stage operations. The transient-diffusion section is expanded to include an example of controlled-release drug delivery.

Section 4, Chapters 21–23: Distillation; Introduction to Multicomponent Distillation; Leaching and Extraction

A chapter on distillation, an introduction to multicomponent distillation, and a chapter on leaching and extraction. The distillation chapters have revised sections on flash distillation, flooding limits and plate efficiency.

Section 4, Chapters 24–27: Drying of Solids; Fixed-Bed Separations; Membrane Separation Processes; Crystallization

Drying gains correlations for drying rates and a treatment of dryer thermal efficiency in this edition. The fixed-bed chapter adds material on powdered carbon for treating aqueous waste in tanks and on expanded-bed adsorption for purifying fermentation broths. Membrane processes and crystallization complete the mass transfer section.

Section 5, Chapters 28–29: Properties and Handling of Particulate Solids; Mechanical Separations

The final section covers particulate solids and their mechanical separation. The publisher lists a new section on diafiltration in Chapter 29, a fuller treatment of ultrafiltration and microfiltration, and a revised discussion of filter cake washing.

Key Concepts

Sections 1–2: Principles and Fluid Mechanics

• Unit operations: the book treats each principal physical operation of a process in its own chapter.
• Transport analogies: this edition gives more emphasis to the analogies among momentum transfer, diffusion and heat conduction, with viscosity, thermal conductivity and diffusivity discussed through parallel simple theories.
• Pumping, metering and mixing: Chapters 8 and 9 apply the flow equations to equipment.

Section 3: Heat Transfer

• Conduction, convection and radiation: conduction (Chapter 10), heat flow in fluids with and without phase change (Chapters 11–13) and radiation (Chapter 14).
• Heat-exchange equipment and evaporation: Chapters 15 and 16.

Section 4: Mass Transfer

• Interphase mass transfer: Chapter 17 on diffusion and transfer between phases.
• Equilibrium stages: Chapter 20, which precedes the distillation and extraction chapters.
• Separation processes: absorption, humidification, distillation, leaching and extraction, drying, fixed-bed adsorption, membranes and crystallization.

Section 5: Particulate Solids

• Handling and separating solids: Chapters 28 and 29, including filtration topics such as filter cake washing and diafiltration.

Critical Analysis

Strengths

• Clear organisation by operation. Each principal unit operation has its own chapter and the sections follow fluids, heat, mass and solids. The preface notes that one-semester courses can be built on any of these sections or combinations of them.
• Theory with practice. The publisher describes a balance of theory and engineering practice, with many illustrative examples, and the preface says the text includes up-to-date correlations for heat transfer, mass transfer and equipment design, which also makes it useful to practising engineers.
• A long-running text with documented revisions. The book dates from 1956. The publisher lists specific changes for this edition (expanded viscosity theory, new adsorption, diafiltration and drying material, revised distillation sections) and says 30 percent of end-of-chapter problems are new or revised. Nearly all can be solved with a pocket calculator, with a few better suited to a computer.
• Some biological examples. The preface points to food processing, bioseparations and diffusion in biological systems, and the publisher highlights diafiltration, adsorption and membrane operations.

Limitations

• Assumes earlier work. The preface expects an introduction to chemical engineering and elementary material and energy balances beforehand. The contents have no chapter that teaches balances, and Chapter 1 is the only introductory chapter.
• Narrow scope. The contents contain no chapters on reaction engineering, thermodynamics, process control or plant design. Bioengineering is not a separate topic, only a set of examples.
• Units. Equations are mostly in SI units, but cgs and fps units remain in places, and students must be ready to move between them.
• Length. With 29 chapters, the book is larger than one course needs, so instructors must select sections.

Where It Fits in the Course

Within the chemical process engineering list, McCabe, Smith and Harriott is the unit operations text. The closest overlap is with Geankoplis's Transport Processes and Separation Process Principles, described on the site as presenting momentum, heat and mass transfer as one unified set and then applying them to separation equipment. McCabe takes the operation-by-operation route that the sections of its contents follow, and the two can be read side by side for the same topics.

Before it comes a first course on balances: Felder, Rousseau and Bullard's Elementary Principles of Chemical Processes teaches material and energy balances, which McCabe assumes, and Denn's Chemical Engineering: An Introduction is a short first-course text. Fogler's Elements of Chemical Reaction Engineering covers reactors, a topic absent here, and Towler and Sinnott's Chemical Engineering Design is the senior-level book that brings the core courses together in process and plant design.

How to Use This Book

The book is meant for junior or senior chemical engineering students who have done the introductory course and balances, and for engineers in industry who want a source of correlations. A practical plan:

• Core: Chapter 1, then the fluid mechanics, heat transfer and mass transfer sections in order, since later sections lean on earlier ones. The preface supports taking one section, or a combination, per semester.
• Selective: Chapters 6, 7 and 9 on compressible flow, immersed objects and mixing, and Chapters 22, 24 and 27 on multicomponent distillation, drying and crystallization, can be chosen to match a course.
• Particulate solids: Chapters 28 and 29 can be read independently of the transport chapters.

Work the end-of-chapter problems, since 30 percent are new or revised, and use the appendix tables of viscosities, thermal conductivities and dimensionless groups when solving them. Check each equation's units against the SI, cgs or fps convention in use.