What qualifications are required to produce LNG cylinders?

LNG cylinders, the full name of liquefied natural gas cylinders, is a highly technical industry that requires production companies to have production personnel, plant sites, and equipment.

The LNG cylinder is designed as a low-temperature adiabatic pressure vessel with a double-layer (vacuum) structure. The inner tank of the low-temperature gas cylinder is used to store liquefied natural gas in low temperature liquid state. The outer wall of the low-temperature gas cylinder is wrapped with multiple layers of thermal insulation material, which has super thermal insulation performance. Together they form a good thermal insulation system. The enclosure and support system are designed to withstand the external forces associated with the vehicle’s driving.

The inner tank is designed with a two-stage safety valve to protect it from overpressure. The main safety valve (opening pressure of 1.59MPa, 230psi) is opened first in the event of overpressure, and its function is to dissipate the pressure rise caused by the normal leakage heat loss of the insulation layer and support, or after the vacuum is broken and under fire conditions The pressure rise caused by accelerated heat leakage. The pressure set point of the auxiliary safety valve (opening pressure is 2.41MPa, 350psi) is higher than that of the main safety valve. When the main safety valve fails or is blocked, the auxiliary safety valve is activated.

Protection of the housing against internal overpressure conditions is achieved by an annular evacuation plug. If the inner tank leaks (causing the jacket pressure to be too high), when the pressure reaches 0.1~0.2MPa, the evacuation plug will open to release the pressure. In the unlikely event that a leak in the evacuation plug would cause the vacuum to break, the casing could be found to “sweat” (large areas of water beading) or even frost. Of course, frost or condensation on the ends of the pipes connected to the gas cylinders is normal.

First, what qualifications are required for the production of LNG cylinders? The production license for low-temperature thermal insulation cylinders should have legal qualifications, and obtain a business license issued by the industrial and commercial administration department or registration with the local government.

Second,  the site and place required for the LNG cylinder manufacturing license, and meet the following requirements:

LNG cylinder manufacturing license B1, B3

1. There are workshops that meet the manufacturing needs of pressure vessel products;

2. There are warehouses and special sites for storing pressure vessel materials and products, with effective protective measures, and the qualified and unqualified areas are clearly marked;

3. There are special warehouses or places that meet the storage requirements of welding materials;

4. There are special sites for pressure test and air tightness test suitable for the manufactured products;

5. There are special places that meet the storage requirements of inspection and testing equipment and equipment. If the manufacturer conducts non-destructive testing by itself, it should have a testing place suitable for the manufactured products, and a special place for ray film washing and evaluation;

6. There are special storage places for regulations, standards and archives of pressure vessel design and manufacture.