30-05-2012, 04:13 PM
Overview of Pressure Vessel Design
Overview of Pressure Vessel Design.pdf (Size: 1.4 MB / Downloads: 326)
INTRODUCTION
Pressure vessels are used in many industries (e.g., hydrocarbon processing,
chemical, power, pharmaceutical, food and beverage). The mechanical design
of most pressure vessels is done in accordance with the requirements contained
in the ASME Boiler and Pressure Vessel Code, Section VIII. Section VIII is
divided into three divisions. This course provides an overview of pressure vessel
mechanical design requirements. It focuses on Division 1, highlights the
differences in scope among the three divisions of Section VIII, and discusses
several factors related to pressure vessel design that the ASME Code does not
cover. The following summarizes the main sections of the course.
General
This section describes the various components of pressure vessels through the
use of conceptual drawings. It also describes the scope of the ASME Boiler and
Pressure Vessel Code Section VIII, and the basic structure of Section VIII,
Division 1.
Main Pressure Vessel Components
Pressure vessels are containers for fluids that are under pressure. They
are used in a wide variety of industries (e.g., petroleum refining, chemical,
power, pulp and paper, food, etc.)
Shell
The shell is the primary component that contains the pressure.
Pressure vessel shells are welded together to form a structure that
has a common rotational axis. Most pressure vessel shells are
either cylindrical, spherical, or conical in shape.
· Figure 2.1 illustrates a typical horizontal drum. Horizontal
drums have cylindrical shells and are fabricated in a wide range
of diameters and lengths.
· Figure 2.2 illustrates a small vertical drum. Small vertical drums
are normally located at grade. The maximum shell length-todiameter
ratio for a small vertical drum is about 5:1.
· Figure 2.3 illustrates a typical tall, vertical tower. Tall vertical
towers are constructed in a wide range of shell diameters and
heights. Towers can be relatively small in diameter and very tall
(e.g., a 4 ft. diameter and 200 ft. tall distillation column), or very
large in diameter and moderately tall (e.g., a 30 ft. diameter and
150 ft. tall pipestill tower).
A tower typically contains internal trays in the cylindrical shell
section. These internal trays (noted in Figure 2.3) are needed
for flow distribution. Several types of tower trays are available,
such as the bubble -cap, valve, sieve, and packed. The
particular type of tray used depends on the specific design
conditions and process application.
Head
All pressure vessel shells must be closed at the ends by heads (or
another shell section). Heads are typically curved rather than flat.
Curved configurations are stronger and allow the heads to be
thinner, lighter, and less expensive than flat heads. Figures 2.1
through 2.4 show heads closing the cylindrical sections of the
subject pressure vessels. Heads can also be used inside a vessel.
These “intermediate heads” separate sections of the pressure
vessel to permit different design conditions in each section.
Overview of Pressure Vessel Design.pdf (Size: 1.4 MB / Downloads: 326)
INTRODUCTION
Pressure vessels are used in many industries (e.g., hydrocarbon processing,
chemical, power, pharmaceutical, food and beverage). The mechanical design
of most pressure vessels is done in accordance with the requirements contained
in the ASME Boiler and Pressure Vessel Code, Section VIII. Section VIII is
divided into three divisions. This course provides an overview of pressure vessel
mechanical design requirements. It focuses on Division 1, highlights the
differences in scope among the three divisions of Section VIII, and discusses
several factors related to pressure vessel design that the ASME Code does not
cover. The following summarizes the main sections of the course.
General
This section describes the various components of pressure vessels through the
use of conceptual drawings. It also describes the scope of the ASME Boiler and
Pressure Vessel Code Section VIII, and the basic structure of Section VIII,
Division 1.
Main Pressure Vessel Components
Pressure vessels are containers for fluids that are under pressure. They
are used in a wide variety of industries (e.g., petroleum refining, chemical,
power, pulp and paper, food, etc.)
Shell
The shell is the primary component that contains the pressure.
Pressure vessel shells are welded together to form a structure that
has a common rotational axis. Most pressure vessel shells are
either cylindrical, spherical, or conical in shape.
· Figure 2.1 illustrates a typical horizontal drum. Horizontal
drums have cylindrical shells and are fabricated in a wide range
of diameters and lengths.
· Figure 2.2 illustrates a small vertical drum. Small vertical drums
are normally located at grade. The maximum shell length-todiameter
ratio for a small vertical drum is about 5:1.
· Figure 2.3 illustrates a typical tall, vertical tower. Tall vertical
towers are constructed in a wide range of shell diameters and
heights. Towers can be relatively small in diameter and very tall
(e.g., a 4 ft. diameter and 200 ft. tall distillation column), or very
large in diameter and moderately tall (e.g., a 30 ft. diameter and
150 ft. tall pipestill tower).
A tower typically contains internal trays in the cylindrical shell
section. These internal trays (noted in Figure 2.3) are needed
for flow distribution. Several types of tower trays are available,
such as the bubble -cap, valve, sieve, and packed. The
particular type of tray used depends on the specific design
conditions and process application.
Head
All pressure vessel shells must be closed at the ends by heads (or
another shell section). Heads are typically curved rather than flat.
Curved configurations are stronger and allow the heads to be
thinner, lighter, and less expensive than flat heads. Figures 2.1
through 2.4 show heads closing the cylindrical sections of the
subject pressure vessels. Heads can also be used inside a vessel.
These “intermediate heads” separate sections of the pressure
vessel to permit different design conditions in each section.