classic | mobile
Follow us on:
Follow us on Facebook  Share via Twitter  Share via LinkedIn
 

Search...
Hi-Tech Security Solutions Business Directory
Residential Estate Security Handbook 2018


Safely tanked
August 2018, Fire & Safety, Products

The storage of flammable liquids carries with it the need to put in place fire protection mechanisms. Tank blanketing is deemed one of the best and effective ways of preventing fires in flammable liquid storage tanks by means of controlling the formation of explosive vapour or air mixtures above the liquid surface.

Lavenda Sekwadi.
Lavenda Sekwadi.

The threat of fires in flammable liquid storage tanks is not far-fetched. Fires can occur at any time for many reasons. Therefore, it is vital to safeguard both human life and material assets from the destructive effects of fires. Tank blanketing valves provide an effective means of preventing and controlling explosions in flammable liquid storage tanks.

Lavenda Sekwadi, process engineer at Energas Technologies, explains that blanketing can reduce evaporation of the stored product and protects the tank from structural corrosion damage caused by air and moisture. He adds that contaminants that may enter the vapour space to cause product degradation are prevented.

“It is a control practice that is widely used in the chemical, pharmaceutical, food processing and petroleum refining industries due to its potential to improve safety,” explains Sekwadi.

Understanding tank blanketing

The operational principle of the blanketing valve is simple; a blanket of inert gas in the tank’s vapour space prevents atmospheric air from entering the tank. “Inert gas is admitted only during the in-breathing cycles (vacuum cycles). An in-breathing cycle occurs when liquid is being withdrawn from a tank or when vapours condense in the tank as a result of a decrease in temperature,” explains Sekwadi. “The amount of inert gas required for a specific application is dependent on the maximum in-breathing demand and the maximum emptying rate.”

Energas tank blanketing valve.
Energas tank blanketing valve.

Nitrogen is the most commonly used gas for blanketing, because, as Sekwadi explains, it is inert, widely available and relatively low-priced. “Other gases such as carbon dioxide or argon are also used on occasions. However, carbon dioxide is more reactive and argon is generally more expensive. The selection of an inert gas for a particular process is based on several properties, including flammability, non-contamination, chemically inactive, non-toxic, availability of large quantities of use and cost effectiveness.”

How it works

Typically, a blanketing valve is mounted on top of a storage tank along with a pressure/vacuum vent and an emergency pressure relief vent. The blanketing valve provides primary vacuum relief for the tank. It opens and supplies gas to the vapour space when pressure decreases to the valve’s set point.

“When vapour space pressure increases, the valve reseals. The pressure/vacuum relief vent is sized to take care of overpressure and vacuum conditions when nitrogen blanketing valve is out of service,” Sekwadi explains, adding that the pressure/vacuum relief vent is sized to take care of overpressure and vacuum conditions when the tank blanketing valve is out of service.

The pressure setting of the vent is set slightly higher than the blanketing valve setting, but below the maximum pressure the tank can withstand. Similarly, the vacuum setting is set higher than the normal operating vacuum but below the maximum vacuum pressure the tank can withstand.

Since the failure of an inert gas poses the danger of a fire, a flame arrester can be mounted upstream of the pressure/vacuum vent to prevent fire propagation into the tank. An emergency pressure relief vent should be considered for the relief of excessive pressure in the case of fire as per API 2000.

Blanketing supplier

Energas Technologies supplies high-end and specialised equipment to the oil and gas industries in southern Africa and has stocked Protectoseal’s range of blanketing valves for the past 12 years.

“There are two types of blanketing valves depending on the actual process requirements: the 1-inch pilot operated (for high flow rate applications) and the 0.5-inch spring operated (for low flow applications) blanketing valves,” says Sekwadi.

Energas has now also added Protectoseal’s Series 10 2-inch Tank Blanketing Valve to its range, which provides capabilities that the existing Series 20 1-inch could not offer in larger flow applications. The valve is specifically designed for tank blanketing and its pilot-operated design offers a very tight operating band. It has the most compact design and fewest external connections of any other pilot-operated valve on the market. With uptime in mind, it is also field serviceable.

For more information, contact Laetitia Botha, Energas Technologies, +27 11 397 6809, laetitia@energas.co.za, www.energas.co.za


  Share via Twitter   Share via LinkedIn      

Further reading:

  • Benefits of a voice alarm system
    February 2019, FDIA (Fire Detection Installers Association), Fire & Safety
    Despite all of the evidence reporting the greatly increased response times and improved evacuation, installations of voice alarm systems are still relatively low.
  • Control via an app
    February 2019, Longse Distribution, CCTV, Surveillance & Remote Monitoring, Integrated Solutions, Products
    Control your home, from anywhere in the world, via the Bitdog remote mobile app.
  • Early warning smoke detection
    February 2019, Technoswitch, Fire & Safety
    Brett Birch, general manager at Technoswitch, discusses very early warning smoke detection systems.
  • Early warning in warehouses
    February 2019, Securiton, Fire & Safety
    Smoke aspiration technology offers a reliable early warning detection system for warehouses where it is often difficult to spot fires before they are out of control.
  • Suprema to license BioSign to Qualcomm
    February 2019, Suprema, Access Control & Identity Management, Products
    Suprema to license BioSign under-display fingerprint algorithm to Qualcomm Technologies.
  • Centurion opens doors
    February 2019, Centurion Systems, Access Control & Identity Management, Products
    Centurion Systems has added a range of door automation solutions to its product stable. Blending aesthetics, whisper-quiet operation and innovative technology.
  • Uniview protects mosque
    February 2019, CCTV, Surveillance & Remote Monitoring, Products
    Uniview provided a complete video surveillance solution to protect the Hassan II Mosque, located in Casablanca.
  • New high-performance Husky NVRs
    February 2019, Milestone Systems, CCTV, Surveillance & Remote Monitoring, Products
    The Milestone Husky X series is a range of network video recorders that unlocks the full potential of Milestone XProtect video management software.
  • Metasys version 9 released
    February 2019, Johnson Controls, Integrated Solutions, Products
    Johnson Controls has released version 9 of its Metasys Building Management Systems (BMS) with a full front-end revamp.
  • TeleEye launches new AHD DVR
    February 2019, TeleEye (South Africa), CCTV, Surveillance & Remote Monitoring, Products
    TeleEye has introduced the Analogue HD DVR, the JN6916 to its latest analogue product line.
  • Cross-campus Wi-Fi connectivity
    February 2019, Education (Industry), IT infrastructure, Products
    Charles Telfair Campus selected Ruckus Networks to deploy its campus-wide wireless network, providing learners and staff with quality Wi-Fi experience for the digital ag
  • Secure borders with mobile surveillance
    February 2019, CCTV, Surveillance & Remote Monitoring, Products
    PureTech Systems’ Command and Control deployed to support border patrol in San Diego. PureActiv software provides common operational picture for mobile surveillance platforms.

 
 
         
Contact:
Technews Publishing (Pty) Ltd
1st Floor, Stabilitas House
265 Kent Ave, Randburg, 2194
South Africa
Publications by Technews
Dataweek Electronics & Communications Technology
Electronic Buyers Guide (EBG)

Hi-Tech Security Solutions
Hi-Tech Security Business Directory (HSBD)

Motion Control in Southern Africa
Motion Control Buyers’ Guide (MCBG)

South African Instrumentation & Control
South African Instrumentation & Control Buyers’ Guide (IBG)
Other
Terms & conditions of use, including privacy policy
PAIA Manual
         
    Mobile | Classic

Copyright © Technews Publishing (Pty) Ltd. All rights reserved.