Comfortable working environment inside Columns

Indian Oil Corporation Limited,
Mathura, Uttar Pradesh


The Mathura Refinery, owned by Indian Oil Corporation, is the sixth refinery of Indian Oil located in Mathura, Uttar Pradesh, India. Crude oil is normally stored in tanks, from where it is passed through Columns like Crude Distillation Unit (CDU) and Vacuum Distillation Unit (VDU), Fluid Catalytic Cracking Unit (FCCU), Hydrotreater Catalytic Reforming Unit (HCU) to get end result. The height of the columns were 60 mtrs.


During the maintenance and repair jobs in the columns like welding, fabrication, riveting job, strip lining, nozzle replacement, trays replacement, etc.) a lot of toxic gases/fumes were released that created a lack of oxygen. Toxic gases can be injurious to the health of workers, engineers & inspection team, etc (can be fatal too). Also, welding work and the presence of a large number of people (nearly 50-75 at a time) inside the column led to temperature increase to approx. 48-50ºC and high humidity was experienced.

Consequently the work environment became uncomfortable and workers took frequent breaks to go out of the column for fresh air. Worker efficiency was affected and the project was expected to get delayed. Quality of the maintenance work inside the column was severely affected, resulting in frequent breakdowns and more shut downs were expected. Shut down periods got extended resulting in huge losses to the refinery (A refinery could lose crores for single day shut down extension).

Also, condensation during night time further worsened the problem causing weak and poor welding quality.

The refinery could not afford to have long shut down periods and loss of worker productivity. Hence, comfortable working condition and maintaining the right RH was necessary inside the columns.

The ambient temperature of the area was 38-40ºC.

problems - comfortable working environment inside columns

Our Solution

TDS recommended humidity level to be maintained below 60% RH and temperature between 30º – 35ºC.

To provide the above parameters TDS suggested a customized solution. Our package included Dehumidifiers, Condensing units, Blowers & ducts along with installation services from our technical manpower to maintain the required RH and temperatures inside the column. Desiccant based dehumidifiers adsorped the excess moisture from the air and maintained RH below 60%. At the same time, the condensing units helped in maintaining the temperature between 25º-26ºC.

The humidity and the temperature inside the column was maintained at below 60% RH and temperature between 25º – 26ºC.


  • Fresh air systems provided air at right temperature
  • Right indoor air quality maintained by removing the toxic gases
  • Productivity of the workers improved
  • Timely completion of the project
  • Quality of welding enhanced
  • Corrosion problems controlled
  • Health of workers, inspectors, maintenance department, engineers remain intact
  • Shut down period reduced which resulted in huge savings

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