What are the main components of flare gas in refineries, and how is it recovered?

Mainly C1, C2, etc., which can be collected in gas holders for use as fuel gas.

Many flare gases are difficult to recover due to their low calorific value and unstable flow rates (such as continuous emissions from safety vents). In other words, recycling is not very cost-effective, and it needs to be considered comprehensively. .

Torch gas mainly consists of C1, C2, and N2, etc. Its flow rate is generally determined by the volume of processing. Nowadays, it is mostly recovered and burned in combustion furnaces, resulting in essentially no or only minimal discharge of torch gas.

The composition of flare gas is mainly C1 and C2, although this can vary depending on the specific situation; in some cases, the nitrogen content is also high. The best way to recover this gas is by installing gas tanks for storage, but such an approach requires a high initial investment. Older facilities generally do not have the means to implement this solution, so new equipment is needed. For older facilities or those that cannot currently be equipped with gas tanks, we use the existing compressors for recovery. For example, while ensuring that the compressor load does not exceed its limits, the safety valve bypass of the constant-pressure top gas compressor is opened to draw in low-pressure flare gas, which is then recovered and used in the desulfurization processes of downstream facilities, where it is integrated into the high-pressure gas system.

Torch gas mainly consists of C1 and C2. A portion of the flare gas can be recovered and used as fuel in the combustion furnace.

The flare gas mainly consists of C1 and C2 compounds; if the safety valve leaks or operates abnormally, C3 and C4 compounds are also present in the flare gas. In addition, the flare gas contains a certain amount of nitrogen as well； The main methods of recovery involve constructing gas holders and compressors to send the gas back to the gas pipeline network.

Some petrochemical plants use water ring compressors to recover flare gas directly.

The composition of flare gas is quite complex; generally, it mainly consists of C1, C2, H2, and N2, with small amounts of C3, C4, H2S, and NH3. We use compressors to draw the gas directly from the flare main pipe, pressurize it, remove sulfur compounds from it, and then send it into the fuel gas network.

The main components are dry gas, namely C1 and C2 components. Building a gas holder requires investment, and dry gas can be used as fuel for equipment in the plant, such as boilers, so there is no need to necessarily burn it off in a flare. For the torch, just leave a lasting light.