Midterm Examination Review Flashcards
(109 cards)
1
Q
three parameters to be defined for plant design
A
- Design
- Process Design
- Plant Design
2
Q
- it is a creative activity
- the synthesis, the putting together of ideas to achieve a desired purpose.
- the creation of manufacturing process to fulfill a particular need.
A
Design
3
Q
establishes the sequence of chemical and physical operations; operating conditions; the duties, major specifications, and materials of construction of all process equipment; the general arrangement of equipment needed to ensure proper functioning of the plant; line sizes; and principal instrumentation.
- summarized by a process flow sheet
A
Process Design
4
Q
7 Steps of Process Design
A
- Flow sheet Development
- Process material and heat balances
- Auxiliary services material and heat balances
- Chemical Engineering performance design for specific items of equipment required for flowsheet
- Instrumentation as related to process performance
- Preparation of specifications in proper form for use by the project team as well as for the purchasing functions
- Evaluation of bids and recommendation of qualified vendor
5
Q
a parameter to be defined which includes items related directly to the complete plant:
1. plant layout
2. general service facilities
3. plant location
A
Plant Design
6
Q
10 DESIGN DEVELOPMENT STAGES
A
- Determine Customer Needs
- Set Design Specifications
- Generate Design Concepts
- Build Performance Models
- Predict Fitness for Service
- R&D if Needed
- Evaluate Economics, Optimize & Select Design
- Customer Approval
- Detailed Design & Equipment Selection
- Procurement & Construction
7
Q
3 types of Engineering Projects
A
A. New process development
B. New production capacity to meet growing sales
C. Modification and addition to existing plant
8
Q
The most important step in starting a process design is translating the customer
need into a _______.
A
design basis
9
Q
T/F. The design basis is a MORE precise statement of the problem that is to be solved.
A
TRUE
10
Q
5 Factors that influence the Design
A
- Information on possible processes and the system of units to be used.
- The national, local or company design codes that must be followed.
- Details of raw materials that are available.
- Information on potential sites where the plant might be located, including climate data, seismic conditions, and infrastructure availability.
- Information on the conditions, availability, and price of utility services such as fuel (gas), steam, cooling water, process air, process water, and electricity, that will be
needed to run the process.
11
Q
-the creative part of the design process
-concerned with the generation of possible solutions for analysis, evaluation, and selection (ways of meeting objective problems)
A
GENERATION OF POSSIBLE DESIGN CONCEPTS (SOLUTIONS)
12
Q
2 Sources of Solutions
A
a. past experiences.
b. tried and tested methods
13
Q
- In the field of chemical engineering, it is usually prohibitively expensive to
build several designs to find out which one works best - a practice known as _____ which is common in other engineering disciplines).
A
prototyping
14
Q
In some cases, the performance model may include a ______ or other facility for predicting plant performance and collecting the necessary design data.
A
pilot plant
15
Q
Instead, the design engineer builds a ______ of the process, usually in the form of computer simulations of the process, reactors, and other key equipment.
A
mathematical model
16
Q
The _______ must assemble all of the information needed to model the process so as to predict its performance against the identified objectives.
A
design engineer
17
Q
______ will include information on possible processes, equipment performance, and physical property data
A
process design
18
Q
If the necessary design data or models do not exist, then _________ is needed to collect the data and build new models.
A
research and development work
19
Q
Once the data has been collected and a working model of the process has been established, then the design engineer can begin to determine the
____________.
A
equipment sizes and costs
20
Q
Step fo design development
-At this stage it will become obvious that some designs are uneconomical and they can be rejected without further analysis.
-From this step a few candidate designs that meet the customer objective are identified.
A
BUILD PERFORMANCE MODEL AND FITNESS TESTING
21
Q
The primary criterion for design selection is usually __________, although factors such as safety and environmental impact may also play a strong role.
A
economic performance
22
Q
The _________ usually entails analyzing the capital and operating costs of the process to determine the return on investment
(R.O.I).
A
economic evaluation
23
Q
T/F. Every design will have several possible variants that make economic sense under
certain conditions.
A
TRUE
24
Q
In regions where energy costs are ___, designs that use a lot of heat exchange surface to maximize recovery of waste heat for reuse in the process will be attractive.
A
high
25
In regions where energy costs are ______, it may be more economical to burn more fuel and reduce the capital cost of the plant
low
26
Very often, the design engineer will find that several designs have very close economic performance, in which case the _______ or that which has the __________ will be chosen.
safest design or best commercial track record
27
When all of the candidate designs have been _____, the best design can be selected.
optimized
28
At the _________, an experienced engineer will also look carefully at the candidate designs to make sure that they are safe, operable, and reliable, and to ensure that no significant costs have been overlooked
selection stage
29
Here the detailed specifications of equipment such as vessels, exchangers, pumps, and instruments are determined.
DETAILED DESIGN AND EQUIPMENT SELECTION
30
During the __________, there may still be some changes to the design, and there will certainly be ongoing optimization as a better idea of the project cost structure is developed.
detailed design stage
31
The detailed design decisions tend to focus mainly on __________ though, rather than on changes to the flowsheet.
equipment selection
32
When the details of the design have been ______, the equipment can be purchased and
the plant can be built.
finalized
33
Procurement and construction are usually carried out by an________ unless the project is very small.
EPC firm (Engineering, Procurement, and Construction)
34
When considering possible ways of achieving the objective the designer will be constrained by many factors which are called the ______.
design constraints
35
2 Types of design constraints
A. Internal constraints:
B. External constraints
36
Type of design constraints: over which the designer has some
control
Internal constraints
37
Type of design constraint: fixed,
invariable
External constraints
38
Process design normally starts with a process scheme also known as
flowsheet
39
The _______ is the key document or road map in process design.
flowsheet
40
It's a diagrammatic model of the process describe the process steps in a proper sequence using symbols to represent the various components (equipment, lines, and control instrumentation) that make up the unit
flowsheet
41
-Shows the arrangement of the equipment selected to carry out the process.
- Shows the streams concentrations, flow rates & compositions.
-Shows the operating conditions.
-During plant start up and subsequent operation, the flow sheet from a basis for comparison of operating performance with design. It's also used by operating personnel for the preparation of operating manual and operator training.
FLOWSHEET
42
2 FLOWSHEET PRESENTATIONS
1. Block Diagram
2. Pictorial Flowsheet
43
FLOWSHEET PRESENTATION
-Represent the process in a simplified form.
-No details involved.
-Don’t describe how a given step will be achieved
BLOCK DIAGRAM
44
FLOWSHEET PRESENTATION
When is it used?
In survey studies.
Process proposal for packaged steps.
Talk out a processing idea.
BLOCK DIAGRAM
45
FLOWSHEET PRESENTATION
-The equipment are normally drawn in a stylized pictorial form.
- For tender documents or company brochures actual scale drawing of the equipment are sometimes used.
PICTORIAL FLOWSHEET
46
4 Types of Pictorial Flowsheets
1. Process Flow Diagram
2. Piping and Instrumentation Diagram
3. Utility Flowsheet
4. Process Safeguarding Flow Diagram
47
A ________ is a simplified flow diagram of a single process unit, a utility unit, a
complete process module.
PROCESS FLOW DIAGRAM (PFD)
48
provide a preliminary understanding of the process system indicating only the main items of equipment, the main pipelines and the essential instruments, switches and control valves.
PROCESS FLOW DIAGRAM (PFD)
49
indicates operating variables, such as mass flow, temperatures and pressures, which are tabulated at various points in the system.
PROCESS FLOW DIAGRAM (PFD)
50
The ____ is a document containing information on:
1. Process conditions and physical data of the main process streams.
2. Main process equipment with design data.
3. Main Process lines.
4. Mass (material) balance.
5. Heat balance (if applicable).
PFD
51
If the PFD doesn’t contain any data about the flow rates, it is called a _______
qualitative flowsheet
52
if the flow rates are involved the PFD is called a _______ in which qualitative information and quantitative data are combined on the basis of one flowsheet.
combined flowsheet
53
shows the arrangement of the process equipment, piping, pumps, instruments, valves and other fittings.
PIPING AND INSTRUMENTATION
DIAGRAM (P&ID)
54
Diagram that should include:
1. All process equipment identified by an equipment number.
2. All pipes identified by a line size, material code and line number.
3. All valves with an identified size and number.
4. Fittings.
5. All pumps identified by a suitable code number.
6. All control loops and instruments.
PIPING AND INSTRUMENTATION
DIAGRAM (P&ID)
55
Used to summarize and detail the interrelationship of utilities such as air, water
(various types), steam (various types), heat transfer mediums, process vents and
purges, safety relief blow-down, etc., to the basic process.
UTILITY FLOWSHEET
56
The _______ is a document containing information on:
1. Main distribution or arrangement of each individual utility system, expect electrical
systems.
PEUFD
57
Diagram: Functions
1. A typical process uses utilities such as water, air and electric power.
2. Water may be used either in the process, or for cooling and/or production of
steam.
3. Air may also be used in the process or for instrument applications.
4. Electric power of course is typically used at various points in the process and
throughout the site.
5. It is always useful to develop diagrams that show the flow and utilization of each
utility.
PEUFD
58
The ______ shall state characteristics and consumption figures of the particular utility concerned, cooling water, fire water, drinking water, steam, plant air, instrument air, fuel oil/gas, inert gas and similar utilities.
PEUFD
59
The ______ is a document highlighting information on:
1. Types and levels of protection offered by the devices installed and their inter
relation to demonstrate the plant’s safety.
2. The P&ID contains all information required;
highlights protection in case of extreme conditions and measures to be taken to
safeguard personnel and environment.
PROCESS SAFEGUARDING FLOW
DIAGRAM (PSFD)
60
Two types of lines on a flowsheet
1) those representing outlines and details of equipment, instruments, etc., and
2) those representing pipe carrying process or utility liquids, solids, or vapors and electrical or instrument connections.
61
complete &____ contains
1) line size (nominal);
2) material cod;
3) sequence number; and
4) materials of construction.
line designation
62
_________ can be developed to suit the particular process, or as is customary a master coding can be established and followed for all projects.
Equipment code designations
63
____ are the basis of process design
Material balances
64
______ is also useful tool for the following:
1. The study of the plant operation & troubleshooting.
2. Check performance against design.
3. Check the instrument calibration
Material balance
65
2 fundamentals of material balance
1. over the complete process
2. over the individual process units
66
fundamentals of material balance: to determine the quantities of raw materials required and production rate
over the complete process
67
fundamentals of material balance: to set the process stream flow & composition
over the individual process units
68
the general mass balance equation:
input - output+ generation-consumption= accumulation
69
general mass balance equation for steady state reaction system
input-output+ generation-consumption=0
70
11 IMPORTANT PARAMETERS FOR REACTIVE SYSTEM
1. Limiting reactant
2. stoichiometry
3. fractional conversion
4. selectivity
5. yield
6. excess
7. tie component
8. bypass
9. recycle
10. purge
11. combustion reaction
71
-It's the reactant that would be completely consumed if the reaction proceeded to
completion.
- As it disappears the reaction stops.
LIMITING REACTANT
72
It's also called the rate determining component since its concentration determines the reaction rate.
LIMITING REACTANT
73
It's used to balance chemical reaction equations.
STOICHIOMETRY
74
For ______ reactions → can be done by inspection
simple
75
For _______ reactions → take a base of 1 mole of one component and make an
atomic balance on each element (It's better to choose one with many atoms as
possible)
complex
76
It's the ratio of amount reacted to amount fed.
FRACTIONAL CONVERSION
77
2 types of conversion:
1. Single pass conversion
2. Overall conversion
78
It's a measure of the efficiency of the reactor in converting reagent to the desired
product.
SELECTIVITY
79
It is the fraction of the reacted material that was converted into the desired product.
SELECTIVITY
80
It's a measure of the performance of a reactor or a plant
YIELD
81
2 types of yield
1. reaction yield
2. plant yield
82
conversion when there is no side reactions take place
Reaction yield
83
a measure of the overall performance of the plant and includes all chemical & physical losses (during separation process).
Plant yield
84
theoretical moles of reagent required per mole of product produced in the reaction balanced equation
Stoichiometric factor
85
____ may be supplied in excess to promote the desired reaction to:
1. Maximize the use of an expensive reagent
2. Ensure complete reaction of a reagent, as in combustion
reagent
86
Excess component _____ feed = Theoretical feed × ( 1 + fraction excess )
actual
87
T/F. If one component passes unchanged through a process unit (inert component), it
can be used to tie the inlet & outlet compositions.
TRUE
88
A flow stream may be divided and some part diverted (bypassed) around some units.
BY PASS
89
This procedure is often used to control stream composition or temperature.
BY PASS
90
It's used to send unused raw materials emerging from a process unit back to the
unit.
RECYCLE
91
A stream that's withdrawn from a process when a species enters in the process feed and is completely recycled.
PURGE
92
used to:
1. Maintain the steady state conditions in the system
2. Prevent the accumulation of inert or undesired materials [to rid the process of the
undesired material]
Purge stream
93
used in combustion to:
1. Ensure complete combustion.
2. Minimize Co & smoke formation.
Excess air
94
T/F. The calculated amount of excess air doesn't depend on how much material is actually
burned but what can be burned.
True
95
volume fraction = mole fraction for gases up to ____ bar.
25
96
A basis of calculation for a process is an ________ of one of the process streams, preferably that stream with known composition.
amount or flow rate
97
the part of the process being considered.
System boundary
98
For any reactive system, the following 4 parameters should be defined:
1. Yield or conversion.
2. % Excess if present.
3. Concentrations (strength) of reactants & products streams.
4. Recovery
99
GENERAL PROCEDURES FOR MATERIAL
BALANCE PROBLEMS:
1. Draw a block diagram of the process.
2. List all the available data.
3. List all the information required from the balance.
4. Write out all the chemical reactions involved.
5. Decide the basis of your calculations.
6. Decide the system boundary
100
used to:
1. Calculate the rate of heat addition or removal from the system to maintain the reaction mixture at the desired temperature to ensure certain degree of conversion.
2. Calculate the flow rates of heating or cooling utilities required.
3. Calculate the heat transfer area required for heating or cooling.
Heat balance
101
8 GENERAL PROCEDURE FOR REACTOR DESIGN
1. Collect together all the kinetic & thermodynamic data on the desired reaction and the possible side reactions (these data are obtained from literature or laboratory & pilot plant test).
2. Collect the physical properties required for the design 9 from literature, estimation by laboratory measurements).
3. Identify the controlling step [Kinetic or mass] and choose the suitable reactor type
based on the experience with similar reactions or from the laboratory or pilot plant work.
4. Make initial selection of the reactor conditions to give the desired conversion & yield.
5. Size the reactor.
6. Select a suitable material of construction.
7. Make a preliminary mechanical design for the reactor.
8. Cost the proposed design (repeat steps 4→8 to optimize the design).
102
3 TYPES OF DESIGN
1. preliminary design
2. detailed design
3. firm process design
103
-Used as a basis for determining whether further work should be done on the proposed process.
- This type of design is based on approximate process methods, and rough cost estimates are prepared.
- Few details are included, and the time spent on calculations is kept at a minimum
PRELIMINARY DESIGN
104
In this type of design, the cost and profit potential of an established process is determined by detailed analysis and calculations.
DETAILED DESIGN
105
8 factors should be established within narrow limits before a detailedestimate design is developed:
1. manufacturing process
2. Material and energy balances
3. Temperature and pressure ranges
4. Raw-material and product specifications
5. Yields, reaction rates, and time cycles
6. Materials of construction
7. Utilities requirements
8. Plant site
106
When the detailed-estimate design indicates that the proposed project should be a commercial success, the final step before developing construction plans for the plant is the ________.
preparation of a firm process design
107
type of design: In this type complete specifications are presented for all components of the plant, without any change in the process flowsheet and accurate costs based on quoted prices are obtained.
FIRM PROCESS DESIGNS
108
4 sources of General information and specific data required to the development of a design project
1. textbook
2. technical journals
3. trade bulletins
4. patents
109
7 Plant Design Cycle
1. Process Design Basic Engg
2. Feed
3. Detail Engineering
4. Pre-Commissioning & Commissioning
5. Stable Operation & Performance Testing
6. Trouble Shooting & Revamp
7. Feasibility Study
