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Shell & tube heat exchanger

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壳牌和管交换器

壳和管热交换器非常常用于工艺业中的优选传热设备。这种类型的热交换器包括通过另一个金属外壳的金属管组成，所述金属管被称为“壳”。

因此，我们通常在管侧上的壳侧和花药液中的液体。两种流体之间的热传递发生在管壁上。

通常，具有不同的壳体和管布置的不同配置是非常容易，以在这方面创造更多更多的亚型category of heat exchangers。这种多功能性是壳牌和管交换器在过程设计工程师中如此流行的原因之一。

壳管交换器设计

壳牌和管道交换机的设计通常由创造的标准管理TEMA (Tubular Exchangers Manufacturers Association)。

壳和管交换器的组件

These are some exchanger parts are important for the overall design of the exchanger -

  • shell
  • shell cover
  • tubes
  • 渠道
  • 渠道cover
  • tubesheet
  • b
  • nozzles

Shell and Tube heat exchanger types

有两种方法可以分类这些交换机 -

A. based on the construction or structure of shell and tube sides
B. based on the service

Structure based classification of shell and tube exchangers

TEMA standards describe these various components in detail. A shell & tube heat exchanger (STHE) is divided into three parts:

  1. 前端
  2. Shell
  3. Rear end

Following table from the TEMA standards explains the different possible configurations for each of the 3 broad parts.

其他较小的部分列于此壳和管热交换器的详细图, along with their correct nomenclature as per the TEMA standards.

许多不同的交换机配置可以通过不同的前端，外壳和后端的不同组合轻松创建。此外，取决于管束如何固定到前端或后端盖上，我们有3个广泛的壳管热交换器施工类型。

  • 固定管板交换机
  • U形管换热器
  • 浮动头交

Exchanger types based on the service

Process fluid which is to be either heated up or cooled down in the exchanger, is commonly referred to as the 'service'. The service may be single phase (either gas or liquid) or two-phase (mixture of gas and liquid).

另一方面，流体（壳体或管侧）中的一个可以是非加工流体，其仅用于加热或冷却过程流体。这些流被称为“实用程序”。实用程序也可以是单相或两相。

壳体侧面和管侧的壳体和管道交换机中可能有两个液体。这导致多种服务组合 -

  • single-phase (both shellside and tubeside)
  • condensing (one side condensing and the other single-phase)
  • vaporizing (one side vaporizing and the other side single-phase)
  • condensing/vaporizing (one side condensing and the other side vaporizing)

Based on such combinations, we can have following types of exchangers -

  • Heat exchanger: fluids on both sides are single phase process fluids
  • 冷却器：一条流是过程流体，另一个是更冷的效用，如空气或冷却水
  • 加热器：一个流体流体和另一个热利用，如蒸汽或热油
  • Condenser: on one side we have two phase flow of with gas at its dew point. This gas is condensed using a cold utility on the other side such air or cold water.
  • Chiller: one stream a process fluid being condensed at sub-atmospheric temperatures and the other a boiling refrigerant or process stream.
  • Reboiler: one stream a bottoms stream from a distillation column and the other a hot utility (steam or hot oil) or a process stream.

Selecting a heat exchanger type

壳体和管交换器的结构基于许多因素来确定 -

    • 两侧工艺流体的性质
    • flow rates on both sides
    • expected nature of operations and maintenance
    • temperature difference on both sides and the required heat transfer area

Heat exchanger design calculations

热的design of the heat exchanger完成以确定所需的整体传热区域，然后根据壳牌ID，数量管及其构造等来确定交换器的大小等。

换热器的热传递由以下等式控制 -

Q = U × Aoverall× LMTD ....... Equation (i)

Here,
Q is the overall heat transfer rate across a given heat exchanger (in Watts)
U is the overall heat transfer coefficient for that exchanger
Aoverallis the overall effective传热面积between the hot and cold sides of the exchanger
LMTD is the logarithmic mean of temperature difference

最常见的，换热器设计软件is used to simulate the performance of a shell & tube exchanger design and then to rate it. But some times, you may prefer to (or have to) do the design calculations manually.

这里有一个list of all important equations管理设计的设计shell and tube heat exchanger。Moreover,以下是一些计算器和教程乐动体育网站怎样to help you with the heat exchanger design calculations.

传热系数

You must be careful to distinguish between the local heat transfer coefficients on shell or tube side AND the overall heat transfer coefficient.

Local heat transfer coefficients are valid only locally and they change along the path of the exchanger. Whereas overall heat transfer coefficient is defined for the whole exchanger, it is independent of the fluid path in the exchanger.

Local coefficients must be multiplied with local temperature difference to get the local heat transfer.

总传热系数乘以LMTD，以提供整体传热速率。

Logarithmic Mean Temperature Difference

Logarithmic Mean Temperature Difference (LMTD) is an indicator of theaverage temperature difference between the hot and cold fluids在换热器中。

LMTD的这种方程被过程设计工程师广泛使用，以获得热交换器尺寸计算的平均温差。但有时这一点LMTD equation can also fail。当温差constand throughout the length of the heat exchanger. You must be careful in such cases to directly使用该恒定温差值, instead of getting trapped in the formula that is prone to fail.

壳牌和管交换器design calculations

热的design for a shell & tube exchanger is done by the process design engineers, using a process simulation software likeHYSYS。在工艺设计之后，机械设计工程师可以参考适用的设计标准，以最终确定热交换器的结构细节。

以下是执行壳牌和管交换器设计计算的一些有用资源 -

乐动体育网站怎样

Tutorials - demo calculations

典型的壳和管交换器图

最后，只有设计和安装热交换器是不够的，工艺工程师还必须仔细设计壳牌换热器周围的管道和仪器。

这里有一个typicalpiping and instrumentation diagram（P＆ID）用于热交换器。它会给你用于设计热交换器系统的有用指针and also for the process control, safety devices, piping and instrumentation around that heat exchanger.

And when you are actually creating a heat exchanger P&ID, you will find thesetypical heat exchanger P&ID symbolsquite handy.

典型的热交换器数据表

Along with theP＆ID.Another important document for the design of heat exchanger system is - the datasheet. The preliminary datasheet prepared by the process design engineer is normally called the 'process datasheet'. Then the equipment design engineer ads more details of the structure of the exchanger to create the 'mechanical datasheet' or equipment datasheet.

这里有一个壳牌换热器的典型数据表。您可以使用此模板为项目创建新数据表，或者只是要了解对Shell和Tube Exchanger设计很重要的不同参数。

Design guidelines and tips for shell & tube exchanger

  • The shell side baffles are used to promote crossflow and enhance the heat transfer between the two fluids. The spacing between shell side baffles has an important impact on the degree of heat transfer. You can use theseguidelines to select the optimal shell side baffle spacing。通常建议根据TEMA标准考虑0.3到0.6倍的壳牌ID之间的挡板间距。
  • Guidelines for the壳管热交换器中的流体分配, i.e. to decide which fluid should go to the shell side and which to the tube side.
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