6.List any four objectives of process control.
Ans:
Suppressing influence
external disturbances, Optimizing
performance, Increasing the productivity, Cost effective.
7.Define process
Ans:
system comprised
dynamic variables usually
involved manufacturing and
production operations. It is defines as a series of operations during which some materials are placed in
more useful state.
8.What do you mean by self regulation?
Ans:
The output will move from one
steady state to another for the sustained
change in input. This means that for change in some input variable the
output variable will rise until it
reaches a steady state (inflow =
outflow). It is the tendency of the process to adopt a specific value of
controlled variable for nominal load
with no control operations.
9.Why do we need mathematical modelling
of process?
Ans:
The physical equipment of the
chemical process we want to control have
not been constructed. Consequently we cannot experiment to determine how
the process reacts to various inputs and
therefore we cannot design the appropriate
control system. If the process equipment needs to be available for
experimentation the procedure is costly.
Therefore we need a simple description of how the process reacts to various inputs, and this is what
the mathematical models can provide to
the control designer.
10.Define interacting system and give an example.
Ans:
Load changes in first process
affects the second process and vise versa
when both are connected in series nature is called interacting system.
Eg. Two level tanks are connected in
series.
11. Distinguish between continuous process and batch process.
Ans:
A process in which the materials
or work flows more or less continuously
through a plant apparatus while being treated is termed as continuous
process. The problem of continuous
process is due to load changes. (e.g.) storage vessel control.
A process in which the materials
or work are stationary at one physical
location while being treated is termed as batch process. (e.g.)
furnace.
12. Explain the function of controller.
Ans:
The element in a process control
loop that evaluated error of the controlled
variable and initiates corrective action by a signal to the controlling
variable.
13. Define Process control.
Ans:
It is the scheme that describes
how much the manipulated variable should
change inorder to bring the controlled variable back to the
setpoint.
14. List the two types of process control.
Ans:
Direct process control Controlled variable directly indicates
the
performance of the process
Eg. Water heater system
InDirect Process control Controlled variable indirectly indicates the performance of the process.
Eg. Annealing
15. What is mathematical modelling.
Ans:
Set of equations that characterize the process is termed as
Mathematical Modelling.
EmoticonEmoticon