Independent research and development of horizontal triple casing high temperature waste heat recovery device

In the past, the nitrogen fertilizer company waste boiler (waste heat boiler) with many accidents, difficult materials selection, and high cost has been replaced by new generations of upgraded technology, and the high-temperature reaction heat of nitrogen fertilizer production can be efficiently and safely utilized. On October 18th, the horizontal triple casing high-temperature waste heat recovery device independently developed by Nanjing Guochang Chemical Technology Co., Ltd. passed the expert appraisal organized by the China Petroleum and Chemical Industry Federation in Beijing. The user of the technology, Li Xuchu, the deputy general manager of the Sichuan Chemical Industry Group, revealed: “Russian customers went to the company recently to seek technical cooperation, saying that our technology is more advanced than theirs for 20 years!”

Experts from the Chemical Industry Industry Productivity Promotion Center and other experts from the appraisal committee evaluated the device as ingenious. It adopts the patented triple-casing technology consisting of an inner tube, a heat insulation tube, and an outer tube to make full use of the high-temperature reaction heat of the ammonia plant above 400° C., and at the same time resolves the conventional equipment because it needs to withstand both high pressure and high temperature. The problems caused by the high accidents and material selection requirements are too high. They have surpassed similar foreign devices and reached the international advanced level.

The highlight of this technological innovation with independent intellectual property rights is shown in the following: The triple-sheath structure makes the high-temperature tube sheet hardly bear the pressure, while the high-pressure tube sheet has the dual protection of the low-temperature process gas and the heat insulation tube and can operate at a lower temperature. Therefore, the problem of tube plate design that originally required to withstand high temperatures and high pressures has been solved. The high-temperature direct-connected tower pot integration, triple-tube boiler tubes, high-pressure headers, and high-temperature header separations developed and designed by Nanjing Guochang reduce the difficulty of material selection and manufacturing difficulty, save investment, and have high heat transfer efficiency. And heat transfer stability.

The technology has been operating stably for 3 years on the 180,000 tons/year synthetic ammonia system of Sichuan Jinxiang Chemical Industry Group, and has achieved good economic and social benefits. The results of the 72-hour on-site assessment conducted by the recently completed expert group showed that under the condition of an intake air temperature of 385°C, the amount of steam produced per ton of ammonia is 0.924 t/t ammonia; the normal design conditions where the process gas inlet temperature reaches 430°C Under the tons of ammonia production steam can reach 1.1t/t ammonia (3.85MPa). Compared with traditional equipment, this technology improves the grade of by-product steam and the amount of steam produced per ton of ammonia, reduces system resistance and reduces heat loss. This simple and scientific device replaces the complicated and huge high-temperature high-pressure alloy pipe, which reduces the construction difficulty and greatly enhances the safety and stability of operation.

According to the person in charge of Nanjing Guochang, the new technology has been successfully applied to more than 20 nitrogenous fertilizer companies so far. The largest scale is the 350,000-ton ammonia ammonia plant of Luxi Chemical Group, which was put into operation last month.