Operational Brief on Shandong Hualu Hengsheng’s 600,000 tons/year ammonia synthesis plant

Thread Content

Brief Report on the Operation of Shandong Hualu Hengsheng’s 600,000-ton/year Ammonia Synthesis Plant / Author/Source: Date: 2018-05-30 Clicks: 195 The 600,000-ton ammonia synthesis project operated by Shandong Hualu Hengsheng Chemical Co., Ltd. utilizes an energy-saving low-pressure ammonia synthesis process as well as patented equipment developed by Nanjing Guochang Chemical Technology Co., Ltd. The plant began the heating and reduction process on March 3, 2018, and started operating at reduced load on March 13; currently, it is operating at 90% of its capacity, with production proceeding smoothly. Its main operating parameters are as follows: Output: ~1800 t/d ； System pressure: ~12.3 MPa ； Pressure difference in ammonia synthesis tower: ~0.22 MPa (pressure difference in steam superheater: about 0.04 MPa) ； System resistance: ~0.7MPa ； Ammonia net value: ~17%. Features of proprietary ammonia synthesis equipment: (1) High tower resistance and pressure drop; small temperature difference within the same plane. The synthesis tower is of full-radial design, with a pressure drop of only 0.22 MPa ； A temperature difference within the same plane of the catalyst bed of <8°C and an ammonia yield of over 17% indicate that the structural design of the fully radial ammonia synthesis tower is reasonable. Since the load is not currently at full capacity, the operating pressure is low; if the operating pressure increases to 12.5–13 MPa, the net ammonia yield can reach 17.5–18%. (2) The use of a directly-connected steam superheater and a three-tube waste boiler ensures safety and reliability, reduces investment costs, and results in high-quality by-product steam in large quantities. By-product superheated steam with a pressure of over 3.80 MPa and a temperature of 407°C is generated, in quantities of approximately 0.96 t per t of NH3; this steam is used directly in the turbines of the syngas compression unit and the ammonia compression unit, enabling the entire ammonia synthesis system to achieve \"zero power consumption\". (3) Modular ammonia coolers are cost-effective, require less space, have low resistance, and result in minimal heat loss. Currently, the resistance of modular ammonia coolers (equivalent to the total resistance of 4 units used in traditional processes) is only 0.1 MPa. The temperature difference between the hot gas inlet and the cold gas outlet of the modular ammonia cooler is < 3.8°C; based on the normal design temperature difference of 5°C for heat exchangers, this reduces \"temperature loss\" by 25–30%. Based on nearly 3 months of operation, the device has been running steadily, with all performance indicators meeting or exceeding the design values. If there is an adequate supply of feed gas, the production capacity can exceed 2100 t/d, and the energy-saving effects will be even more significant.