Method for producing ammonia synthesis gas from coke-oven gas

Abstract

The invention relates to a method for producing ammonia synthesis gas from coke-oven gas. The method comprises the steps of: by taking coke-oven gas subjected to dedusting, decoking and rough desulfurization as a raw material, firstly separating out hydrogen in the coke-oven gas for later use; respectively converting remaining high methane gas with vapor and air, further converting into conversion gas containing hydrogen and carbon dioxide after converting hydrocarbon gas into hydrogen and carbon monoxide; after removing carbon dioxide from the conversion gas, mixing the remaining gas from the separated hydrogen, and finally purifying through a terminal to obtain ammonia synthesis gas, wherein all operation units can be operated by a conventional mode. Compared with the conventional method in which pure oxygen or high oxygen is needed, with the method, the higher water vapor partial pressure and higher conversion rate can be obtained under the conditions of water vapor using the same water-air ratio and water-carbon ratio, the investment can be reduced, the utilization ratio of raw materials can be improved, the energy consumption and gas consumption can be remarkably reduced, and the economic benefits can be obvious.

Description

technical field [0001] The invention relates to a method for producing ammonia synthesis gas from coke oven gas. Background technique [0002] Synthetic ammonia is one of the important raw materials for the manufacture of fertilizers and many chemical products. The preparation of the required ammonia synthesis gas has gone through the early water gas or semi-water gas produced with coal and coke as raw materials, and then gradually replaced by natural gas which is convenient for pipeline transportation and can reduce the operation cost of synthesis gas preparation and subsequent processes. The process of preparing ammonia synthesis gas from natural gas is to desulfurize the natural gas first, then add water vapor and air to carry out catalytic conversion, and obtain hydrogen-containing 2 , CO, CO 2 , N 2 and H 2 After the mixed gas of O, the conversion of carbon monoxide into equivalent hydrogen and carbon dioxide, decarburization (removal of carbon dioxide) and termina...

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Problems solved by technology

Therefore, the heat-exchanging steam catalytic conversion method more effectively recovers and utilizes the heat of the high-temperature gas at the outlet of the reformer, but the consumption of heat and steam is still relatively large, and the conversion process also needs to add oxygen-enriched air to achieve the ammonia synthesis gas. Need H 2 / N 2 =3 requirements

[0009] It can be seen from the above-mentioned main methods and conversion processes of producing ammonia synthesis gas from coke oven gas that the conversion reaction temperature is higher than 1000 °C, especially the conversion temperature of non-catalytic partial oxidation is even as high as 1400~1600 °C, which can Large energy consumption and high equipment requirements, the external heating steam catalytic conversion method has abundant steam generation, but the energy consumption is high; the heat exchange steam catalytic conversion method has basically balanced steam and low energy consumption, but it is used to reduce the amount of nitrogen introduced Ammonia synthesis gas needs to use pure oxygen or oxygen-enriched air in the coke oven gas to achieve the final required qualified hydrogen-nitrogen ratio, so it needs to be supplemented with oxygen production, which leads to the increase of corresponding oxygen production equipment, which not only increases The complexity of operation also increases equipment investment