Midterm Examination Review Flashcards
three parameters to be defined for plant design
- Design
- Process Design
- Plant Design
- 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.
Design
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
Process Design
7 Steps of Process Design
- 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
a parameter to be defined which includes items related directly to the complete plant:
1. plant layout
2. general service facilities
3. plant location
Plant Design
10 DESIGN DEVELOPMENT STAGES
- 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
3 types of Engineering Projects
A. New process development
B. New production capacity to meet growing sales
C. Modification and addition to existing plant
The most important step in starting a process design is translating the customer
need into a _______.
design basis
T/F. The design basis is a MORE precise statement of the problem that is to be solved.
TRUE
5 Factors that influence the Design
- 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.
-the creative part of the design process
-concerned with the generation of possible solutions for analysis, evaluation, and selection (ways of meeting objective problems)
GENERATION OF POSSIBLE DESIGN CONCEPTS (SOLUTIONS)
2 Sources of Solutions
a. past experiences.
b. tried and tested methods
- 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).
prototyping
In some cases, the performance model may include a ______ or other facility for predicting plant performance and collecting the necessary design data.
pilot plant
Instead, the design engineer builds a ______ of the process, usually in the form of computer simulations of the process, reactors, and other key equipment.
mathematical model
The _______ must assemble all of the information needed to model the process so as to predict its performance against the identified objectives.
design engineer
______ will include information on possible processes, equipment performance, and physical property data
process design
If the necessary design data or models do not exist, then _________ is needed to collect the data and build new models.
research and development work
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
____________.
equipment sizes and costs
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.
BUILD PERFORMANCE MODEL AND FITNESS TESTING
The primary criterion for design selection is usually __________, although factors such as safety and environmental impact may also play a strong role.
economic performance
The _________ usually entails analyzing the capital and operating costs of the process to determine the return on investment
(R.O.I).
economic evaluation
T/F. Every design will have several possible variants that make economic sense under
certain conditions.
TRUE
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.
high
In regions where energy costs are ______, it may be more economical to burn more fuel and reduce the capital cost of the plant
low
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
When all of the candidate designs have been _____, the best design can be selected.
optimized
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
Here the detailed specifications of equipment such as vessels, exchangers, pumps, and instruments are determined.
DETAILED DESIGN AND EQUIPMENT SELECTION
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
The detailed design decisions tend to focus mainly on __________ though, rather than on changes to the flowsheet.
equipment selection
When the details of the design have been ______, the equipment can be purchased and
the plant can be built.
finalized
Procurement and construction are usually carried out by an________ unless the project is very small.
EPC firm (Engineering, Procurement, and Construction)
When considering possible ways of achieving the objective the designer will be constrained by many factors which are called the ______.
design constraints
2 Types of design constraints
A. Internal constraints:
B. External constraints
Type of design constraints: over which the designer has some
control
Internal constraints
Type of design constraint: fixed,
invariable
External constraints
Process design normally starts with a process scheme also known as
flowsheet
The _______ is the key document or road map in process design.
flowsheet
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
-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
2 FLOWSHEET PRESENTATIONS
- Block Diagram
- Pictorial Flowsheet
FLOWSHEET PRESENTATION
-Represent the process in a simplified form.
-No details involved.
-Don’t describe how a given step will be achieved
BLOCK DIAGRAM