High pressure:Problems with moisture

Problems with moisture

With materials that are hygroscopic, air drying is normally recommended. For the majority of materials this is not generally necessary. With compressors, however, large quantities of moisture can be generated if the supply air is warm and humid, and this moisture can be carried over into the air supply lines. With materials such as fly ash and cement this moisture can cause blinding of the blow tank fluidizing membrane, which can result in a significant increase in pressure drop across the blow tank and hence a reduction in performance of the conveying system.

Owing to the intermittent nature of the conveying process it is also possible for water to collect in the air supply lines and this can be blown into the blow tank on start up. This has resulted in partial blockage of the blow tank discharge line on several occasions with both fly ash and cement in pneumatic conveying systems operated by the author. This particular topic of moisture and condensation is considered in detail in Chapter 25.

Pipeline feeding devices Part Part 2- High pressure-0053

Road and rail vehicles

Many road and rail vehicles used for the transport of bulk solids are essentially blow tanks. In the case of road tankers the vehicle usually has its own air supply for off- loading. These are generally rated at a pressure of 1 bar gauge and positive displace- ment blowers are used for the purpose. Rail vehicles generally rely on a site air supply for off-loading, with a much higher air pressure. A standard carriage length rail wagon transporting cement would typically carry about 70 tonne.

Related posts:

System and process requirements:Supply and demand controlled systems
Applied Pneumatics:Flow analysis for cylinders and valves
Compressed Air Transmission and Treatment:Compressed air distribution
Energy and Efficiency:ENERGY GENERATION AND DISPERSAL
System selection considerations:System economics and Material considerations
Low pressure and vacuum:Hopper off-loading and Trickle valves
Introduction to pneumatic conveying and the guide:Definitions and Solids loading ratio
Fine material:Procedure and Operating point
Conveying capability:High pressure conveying – Part III
ROUBLESHOOTING PNEUMA TIC CIRCUITS:Rotary Screw Compressors
Control components in a hydraulic system:Manifolds
Servo valves.
Fundamental Principles:fluId flow
ENTROPY:THE ENTROPY CHANGE OF IDEAL GASES
POWER AND REFRIGER A TION CYCLES:THE IDEAL VAPOR-COMPRESSION REFRIGERATION CYCLE

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