Measurement of Mass Flow Rate of Pneumatically Conveyed Solid

Table of Contents

Chpater I2

Introduction2

Purpos of Study3

Chapter II4

Literature Review4

Indirect measurements4

Electrical sensors for measuring volumetric concentration of solids5

Capacitance sensors6

Electrostatic sensors6

Attenuation and scattering methods for measuring concentration of solids8

Radiometric sensors8

Optical sensors9

Acoustic sensors.10

Resonance sensors for measuring concentration of solids12

Tomography methods for measuring concentration of solids13

Electrical capacitance tomography (ECT)14

Chapter III1

Proposed Research Methods1

References1

CHPATER I

Introduction

Pneumatic conveyors are often used to transport pulverized and granular materials from one level to another in a large number of industrial processes involving bulk solids handling and control. In order to achieve efficient utilization of energy and raw materials, an accurate, reliable, on-line, continuous and non-invasive measurement of solids' mass flow rate in pneumatic conveying pipelines has become increasingly significant. And solids' mass flow rate measurements have been highly concerning by both industries and researchers. Many different methods and techniques have been studied and developed for metering mass flow rate of solids in pneumatic transport systems over last two decades.

However, each technique presents its own advantages and limitations under different application conditions. Further research needs to be done urgently in terms of the accuracy, the reliability, the robustness and the sensitivity of the measurement instruments. There have been some comprehensive reviews of the topic in the open literature at different research stages in this area. Yan reviewed all proposed methodologies with particular reference to their sensing principles, individual characteristics and the research state of the development in 199

An overview of some commonly used non-invasive mass flow rate measurement techniques was presented by Arakaki et al. in 200 Arakaki briefly summarized the measurement principles, the developments of the measurement instruments and the main limitations of three kinds of techniques, which were: capacitive techniques, ultrasonic techniques and microwave techniques. Ahmed and Ismail presented a review on a range of existing techniques used to measure solids concentration and velocity in gas- solid flows in 2008, such as those widely used in pneumatic conveying system: capacitance sensors, electrostatic sensors and electrical capacitance tomography (ECT) systems. The reviews mentioned above focused on the principle, the individual characteristics and the state of each method and technique at different development stages.

Although review work has previously been done on different topics at different stages in this area , many novel measurement techniques have come into sight in recent years. In this paper, a comprehensive review on latest techniques and possible approaches over a wide range of topics in developing mass flow meter of pneumatically conveyed solids has been conducted to give main categories and summaries. On basic principle and configuration of each measurement technique, performances and limitations of the technique in industrial applications are analysed and compared from different views to demonstrate the recent developments in the field and the possible approaches which may provide solutions to the solids' mass flow measurement problem.

The paper is organized in a way that an introduction is firstly presented to show the intention and the purpose of conducting the review, followed by two main parts, ...