Recycling of waste gases from ammonia synthesis production

It depends on the different gas components! Pressure swing adsorption yields hydrogen with a low hydrogen content, which can be recovered for combustion in waste treatment facilities to recover heat ； There is air leakage at the packing of the compressor and circulation pump; the exhaust gas analyzed contains a high level of hydrogen, which can be recovered and used as feed gas in the compressor.

1. Use pressure swing adsorption to recover the gas released during synthesis, and return it to the ammonia synthesis system or for hydrogen peroxide production. 2. The air leakage from the packing of compressors and circulators, as well as the oil containing air discharged by compressors, is recovered and sent to the ammonia synthesis system or small gas tanks as fuel gas. 3. The copper-washed recycled gas is recovered and fed into the ammonia synthesis system. 4. Carbonized exhaust gas recovery ammonia synthesis system. 5. Ammonia tank and alcohol tank vent gas recovery for the ammonia synthesis system. 6. Ammonia synthesis system using hydrogenated tail gas from hydrogen peroxide. That’s about it. Of course, all the recovered gas can be used as fuel gas!

An investment of 32 million yuan has been made to adopt a more advanced alcohol-oil conversion production technology, replacing the traditional copper washing process in ammonia synthesis. This approach prevents gases and liquids such as copper melt, ammonia, acetic acid, carbon monoxide, and carbon dioxide from contaminating the atmosphere and surface water. Meanwhile, the trace amounts of carbon monoxide and carbon dioxide present in the synthetic ammonia feed gas can be converted into crude methanol with a purity of 90%-96% through the alcohol-to-hydrocarbon conversion system. It is estimated that the company can recover 50,000 tons of methanol per year, generating output worth over 90 million yuan; at the same time, it reduces emissions of harmful gases such as carbon monoxide and carbon dioxide by more than 30 million cubic meters per year. To address the issue of gases such as hydrogen, nitrogen, and carbon dioxide – with a total emission rate of 2,500 cubic meters per hour – generated in the carbon removal unit during ammonia synthesis, and to prevent air pollution resulting from direct discharge of these gases, they invested over 8 million yuan to install a new pressure swing adsorption system for carbon dioxide removal. This device can also purify the hydrogen in the exhaust gases to over 60% for use in ammonia synthesis, reducing the coal consumption per ton of ammonia by 20 kilograms. The company has carried out scale and technical upgrades to the membrane separation system used in the synthetic ammonia production process, enabling it to handle 1,200 cubic meters of synthetic ammonia waste gas per hour, which reduces annual waste gas emissions by 8 million cubic meters. On the one hand, the modified device can cyclically absorb trace amounts of ammonia present in the waste gas; it is capable of recovering 2 tons of dilute ammonia water per hour. This ammonia water is sent to the carbonization section where it can be further concentrated to serve as a raw material for producing ammonium carbonate, with the waste ammonia being recovered and converted into ammonium carbonate. On the other hand, the large amount of hydrogen contained in the exhaust gas is purified to over 96% and sold, with a maximum of 600 cubic meters of hydrogen dapat be recovered per hour. At a selling price of 2 yuan per cubic meter, the annual cost savings can reach over 7 million yuan.