As the country faces the second wave of the Covid-19 crises, shortages of oxygen have been reported from several states. Apart from the shortage of oxygen, another problem the country is facing is the shortage of tankers suitable to transport and store oxygen, especially liquid oxygen. As a result, Liquid Nitrogen Gas Tankers have been converted to Liquid Oxygen Tankers.
As this conversion is a dangerous process, the government of India proposed a Standard Operating Procedure (SOP) for the conversion of used LNG tankers for Oxygen service. Noting that such conversion inherent risk and against the international practice, the Petroleum and Explosives Safety Organization (PESO) has issued the SOP for the user industry.
In its memo, the department said that the industries had proposed conversion of LNG (Liquid Natural Gas) tanker to Oxygen service. As of now, there are 138 such tankers in the country. PESO said that traditionally the conversion was not agreed by the department to carry and transport liquid Oxygen due to the risks. However, due to extreme emergency requirement to transport liquid Oxygen, the department has issued the guidelines to be followed to convert the tankers.
It may be noted that the govt had allowed the conversion of cylinders of inert gases to oxygen cylinders in April last year, and the SOP for the same was issued. Now the same has been allowed for tankers.
PESO said, “Since such conversion is not a safe practice and not followed internationally, extreme precaution has to be taken by the applicant for such conversion. The conditions set forth by PESO in view of the above extreme exigencies.” The guidelines issued by the PESO includes:
- In its proposed SOP, PESO said that during the conversion process, the tanker should be warmed up and purged with hydrocarbon free nitrogen. The hydrocarbon vapour concentration must be reduced to 0.01%.
- It is essential to ensure inlet of the vaporizer coil/pump suction filter and any other points of the system are free from hydrocarbon.
- Only a competent and experienced person will be allowed to supervise the conversion.
- All valves, piping works, filling and sampling hoses and pump assembly must be made up to the Oxygen compatible material.
- Purged gas analysis shall be carried out, and samples to be taken for the consistent concentration of hydrocarbon vapour less than 1PPM, and the process must be repeated three times.
- The department said that PESO should be informed while deciding on the conversion of LNG tanker for oxygen supply. The applicant should submit a declaration to PESO for acceptance and issue of commissioning permission to use tanker for Oxygen service. The authorized signatory will be solely responsible for compliance with the conditions laid down by PESO.
The complete set of proposed guidelines can be read here.
Relaxation of rules announced for oxygen cylinders and tankers
The government of India has also announced relaxation in rules for oxygen cylinders and cryogenic vessels. In its memo issued on April 26, PESO said that due to high stress on the mobility of liquid Oxygen within the country as well as the availability of gas cylinders, relaxation in the Rules had been considered by DPIIT, Ministry of Commerce and Industry, Government of India.
The department extended the licenses for cylinders that were due testing on March 31 or up to June 30 under Gas Cylinder Rules 2016 to June 30 2021. The cryogenic vessels for storage of liquid Oxygen and for transportation of liquid Oxygen, liquid nitrogen & liquid argon, which are due for testing between March 30 to June 30, will remain operational till June 30 if they have valid license and certificate under Rule 18 & 19 of the SMPV (U) Rules, 2016. The date for a license has also been extended to June 30.
SOP for conversion of Nitrogen, Argon, Helium cylinders for Oxygen supply
Earlier in April last year, PESO had issued SOP for conversion of Nitrogen, Argon, Helium cylinders for Oxygen supply. The department said that the tanker should always be warmed up and purged with hydrocarbon-free nitrogen before being filled with Oxygen. Any conversion shall be covered either by a Work Permit or a Management of Change (MOC) order.
Operators must check the equipment to confirm that there has not been any contamination of the cylinders. The inner vessel should be designed and constructed for oxygen service, e.g. stainless steel or 9% nickel alloy. All valves, pipework, filling and sampling hoses, and pump assembly are of Oxygen compatible materials. The pump and its accessories are suitable for the required application after conversion, e.g. oxygen compatible gearbox oil.
After the purging of the cylinders, the loading and off-loading connector shall be replaced according to the desired product. The use of adaptors should be limited and, if possible, eliminated. All adaptors should have IDs legibly marked on a visible surface. Adapters must be permanently constructed by means such as welding, silver soldering or brazing so that parts cannot inadvertently become detached while being used. Worn out or damaged adapters must be withdrawn from service. As a minimum, adaptors should be of compatible material, cleaned for Oxygen service and having a valid pressure test certificate. Complete SOP can be read here.
Covid situation in India
According to the Ministry of Health and Family Welfare, India reported 3,62,913 new Covid-19 cases on April 27. The total number of cases reported so far stands at 1,79,88,793. There are 29,71,959 active cases in the country. 1,48,08,006 patients have recovered out of which 2,62,339 were discharged on April 27. So far 2,01,166 people have lost their lives out of which 3,286 died on Monday.
