tailieunhanh - AIR POLLUTION CONTROL EQUIPMENT SELECTION GUIDE - CHAPTER 13

Giải quyết phòng thiết bị loại Một trong những đơn giản nhất (và lâu đời nhất) thiết bị kiểm soát ô nhiễm không khí là phòng giải quyết. Đây cũng là đôi khi được gọi là loại bỏ các hộp hoặc bỏ hộp. Thiết bị là trong hình thức một căn phòng lớn, cho phép giảm vận tốc khí đến một điểm nơi mà các hạt mang chỉ đơn giản là giọt. Ngày nay, phòng giải quyết được sử dụng để loại bỏ thô của hạt lớn trước của thiết bị kiểm soát hiệu quả cao hơn hạt. Họ hiếm khi, nếu. | chapter 13 Settling chambers Device type One of the simplest and oldest air pollution control devices is the settling chamber. These are also sometimes called knock out boxes or drop out boxes. The equipment is in the form of a large chamber which allows reduction of the gas velocity to a point where the particulate it carries simply drops out. Today settling chambers are used for coarse removal of large particulate in advance of higher efficiency particulate control equipment. They are rarely if ever used as the final gas cleaning device. Typical applications and uses Settling chambers are primarily used to reduce the loading of particulate from sources such as kilns calciners and mills or grinders that inherently produce high particulate concentrations. If the particulate is valuable in a dry form the settling chamber usually is designed to settle out the smallest size particle that can economically be separated. If the product is not valuable or further downstream particulate separation is to be used such as a cyclone scrubber or fabric filter collector the chamber is usually sized to afford some basic separation at low cost. They are often followed by product recovery cyclones which are in turn followed by collectors designed for high efficiency collection of the fine particulate that pass through the upstream devices. Operating principles A settling chamber operates on the principle that if you slow a gas stream down sufficiently the solid particulate contained within that gas stream will settle out by gravity. In general the larger the particle the faster the settling rate. In addition larger particles will settle out faster in a given moving gas stream than smaller particles. 2002 by CRC Press LLC The settling velocity for particulate was explored extensively in the mid-1800s by a scientist named Stokes. His equation for the terminal settling velocity of particulate is used to this day. It is called Stokes Law Vg D2 dp - dg g 18v Where Vg terminal settling .