New at PipingDesign.com: 29 June 2000

A few selected links from Chemical Engineering World:

Thermal Relief Valve (TRV) protects the equipment/pipe lines against possible over pressurization caused by liquid expansion due to heat ingress. This article discusses, its requirement, location, set pressure, over pressure, size and discharge disposal.

Introduction

As the name indicates it is the device to release the over pressure caused by liquid expansion either due to over heating by heat tracers, solar radiation or external fire.

The estimated pressure rise for most of liquids ranges from 5 to 20 kg/cm2 for each degree centrigrade of temperature rise. But in field, pressure rise does not match with the calculations. This is due to system rarely filled completely and also small leak through valve sheet, flanged, reduces the pressure drastically.

The thermal relief valves are normally recommended on :

i) Piping or vessel completely filled in with cold liquid and blocked in heated by steam/electrical tracer, steam jacket, solar radiation or external fire.

ii) A heat exchanger blocked in at the cold side and hot side is on.

iii) Parallel filters, when one is isolated during operation.

For a link to the full article, see
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Thermal Relief Valve, Chemical Engineering World

The various process plants we come across are Petroleum Refineries, Petrochemical Complexes, Fertiliser Plants, and Chemical and Pharmaceutical Plants which need special attention due to the nature of materials and products handled in those plants.

For a link to the full article, see
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Equipment Layout and Plot Plan - Various Considerations, Chemical Engineering World

Vents and drains are the critical requirements of any Chemical Process Industry (CPI). Though the basic concept of venting and draining of any system is simple i.e. these are required for removing air or gases and draining of liquids respectively, experience plays a major role for proper provision of vents/drains. Absence or under sized vents/drains may even cause the failure of plant startup or plant hardware like equipment, pipelines etc. Various practical aspects for vents/drains commonly used in CPI are discussed in this article.

CLASSIFICATION As per the requirement, vents and drains are classified into following three categories : (a) Process , (b) Maintenance and (c) Hydraulic Test Vents/Drains.

For a link to the full article, see
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Venting and Draining of Piping Systems, Equipment and Vessels, Chemical Engineering World Received on Thu Jun 29 00:04:00 2000