Natural gas type synthesis ammonia energy-saving and emission-reduction technology

Abstract

The invention discloses a natural gas type synthesis ammonia energy-saving and emission-reduction technology, which is characterized in that: a methodology of process systems engineering is adopted torealize mass-energy comprehensive integration, particularly comprising the following steps: carbon dioxide in one section of furnace flue gas is recovered by adopting a combined method of membrane separation and chemical adsorption; deeply cooling, distilling and recovering argon gas in purge gas of a hydrogen recovery device; a great quantity of low-temperature waste heat at the outlet positionof the top of a regenerating tower and an ice engine is recycled by adopting heat pump technology, so as to save cold of the ice engine and pre-heating boiler water; a similar device is used as a reference, the proposal is close to zero discharge, greenhouse gas emission load can be reduced by 50 percent to 100 percent, and carbon dioxide and argon gas are by-products at the same time, and the unit consumption of a product can reach 31GJ / tNH3, and compared with the original process, the energy saving can reach 5 percent to 15 percent. The technology is particularly suitable for the existing synthesis ammonia device which takes natural gas as raw material, so as to carry out energy-saving and emission-reduction technology reconstruction, the energy consumption of the natural gas type synthesis ammonia device based on the design of the proposal is the lowest level in the national similar devices.

Description

technical field [0001] The invention belongs to the technical field of petrochemical, chemical fertilizer and other process industries, and in particular relates to an energy-saving and emission-reducing process technology of a natural gas-type ammonia synthesis device. Background technique [0002] Ammonia is one of the important chemical products and occupies an important position in the national economy. Most nitrogen fertilizers used in agriculture are produced from ammonia. The world's annual synthetic ammonia output has reached more than 100 million tons, of which about 80% ammonia is used to produce chemical fertilizers, and 20% is used as raw materials for other chemical products. Synthetic raw materials mainly include natural gas, light oil, heavy oil and coal. Based on the consideration of plant economy, coal and natural gas are used as the main raw materials of ammonia synthesis plants in my country. At present, there are about 22 sets of large-scale natural ga...

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Problems solved by technology

[0005] Chinese patent CN01134103.3 "Compound amine solvent for recovering low partial pressure carbon dioxide" proposes to use amine solution to directly recover low partial pressure carbon dioxide and apply it to flue gas recovery in Chitianhua, Guizhou, but the recovery of carbon dioxide is only three to four tons per hour

However, there is no report on the application of heat pump technology in the ammonia synthesis plant to recover low-temperature waste heat and save cooling capacity.

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