What Is Outgassing?

Purge gas (English name purge gas) also forms exhaust gas, exhaust gas, etc. It is a material name in chemical production. In many chemical productions, in order to maintain a balanced, efficient, normal, and stable operation of the chemical reaction, the gas generated from the side reactions in the chemical process or the remaining components of the mixed gas raw materials are often used. All or part of the chemical process can no longer be used with low taste. The gas component is continuously or periodically discharged from the production unit, and this part of the gas is called purge gas. For example, a large amount of purge gas is emitted during the production processes such as synthetic ammonia, synthetic methanol, and ethylene oxidation to ethylene oxide. It is different from the gas temporarily discharged due to accidents, abnormal production, equipment cleaning, replacement and other processes. ^[1]

Purge gas (English name purge gas) also forms exhaust gas, exhaust gas, etc. It is a material name in chemical production. In many chemical productions, in order to maintain a balanced, efficient, normal, and stable operation of the chemical reaction, the gas generated from the side reactions in the chemical process or the remaining components of the mixed gas raw materials are often used. All or part of the chemical process can no longer be used with low taste. The gas component is continuously or periodically discharged from the production unit, and this part of the gas is called purge gas. For example, a large amount of purge gas is emitted during the production processes such as synthetic ammonia, synthetic methanol, and ethylene oxidation to ethylene oxide. It is different from the gas temporarily discharged due to accidents, abnormal production, equipment cleaning, replacement and other processes. ^[1]

1. Relaxation and deflation has the following characteristics:

(1) For a set of normal and stable chemical production equipment, the amount of released gas, composition, and relaxation time are related to the industrial route, production scale, and operating conditions of the chemical equipment. For example, the composition of the purge gas in the ammonia plant: 60 ~ 70% hydrogen, 20 ~ 25% nitrogen, 3 ~ 8% argon, 7 ~ 12% methane, trace ammonia <200ppm, and the rest also contains trace helium, neon, Wait. This is because the ammonia synthesis process uses air and water as raw materials and reacts with carbon-containing materials such as coal and methane to produce gas. After oxygen is consumed, the remaining air is composed (argon, helium, neon, krypton, etc.), and the remaining part (hydrogen, hydrogen, Nitrogen, etc.), side reactions (methane). Periodic emissions are required to maintain reaction balance and efficiency;

(2) The composition, quantity, discharge location, and discharge mode of the release gas are determined at the time of device design, so they are basically known and controllable.

(3) The relaxation gas contains harmful and useful components. Generally, the concentration is low, the taste is low, and the added value is low. However, directly discharging it into the atmosphere will cause pollution to the environment, such as synthetic ammonia as methane and ammonia. Ethylene in the purge gas of the ethylene oxide plant; therefore, it must be utilized and treated to meet environmental protection emission requirements.

2. Chemical reuse of the purge gas is an effective way to improve the economic and environmental benefits of the device; the purge gas often contains many useful and valuable components, such as methane and hydrogen in synthetic ammonia purge gas. Lower, why use some separation methods to increase the concentration to the available content. For example, pressure swing adsorption technology can be used to condense hydrogen, which can achieve a purity of more than 95%. It is cheap and good quality as a raw material for the hydrogenation process. Concentration of methane as a fuel not only solves the problem of environmental protection, but also uses hydrogen with high added value. Thus, the overall benefit of the ammonia synthesis device is also improved.

Purge gas is a term used in chemical production. It is a collective name for those gases that have not participated in the synthesis reaction in the production process of the chemical process and are eventually discharged as waste in the production process of the synthesis process . Its scope is very wide, it can be synthetic ammonia, or synthetic methanol, or it can be the gas emitted in the process of synthesizing other chemical products.

Ammonia degassing: Because the ammonia sent to the ammonia system by the synthesis system decreases in pressure, the non-condensable gases dissolved in it such as nitrogen and hydrogen volatilize and a small amount of evaporated ammonia is collectively called ammonia degassing. These gases can be sent to a pure ammonia tower for absorption with demineralized water, and the ammonia contained in them can be recovered to form ammonia water. The tail gas is sent to a blower for combustion or sent to a low-pressure membrane to recover hydrogen.