What is the large-scale fertilizer production process? What are the main differences from traditional ammonia synthesis processes?

It is generally understood that a single system capable of producing 300,000 tons per year of synthetic ammonia and 520,000 tons per year of urea is considered to be a large-scale nitrogen fertilizer plant.

Waiting. . . . . . . . . . . . .

In fact, the manufacturing processes remain largely unchanged. 1\ In terms of scale, at the current level, ammonia production still dominates, with capacities exceeding 300,000 tons. 2\ Continuous production methods are used. 3\ Control is carried out using DCS and ESD systems. 4\ Coal gasification or coal slurry processes are primarily employed; the decarbonization processes are also well-established, and such technologies are available in China. 5\ Energy consumption levels: I can’t recall the specific figures. 6\ Pollutant emission control technologies must be advanced. 7\ The layout should be rational, taking into account factors such as factory location, safety distances, as well as the radius for accessing resources and selling products. This point was added by me, as I consider it necessary.

I think it makes sense for everyone to continue the discussion

1. For large-scale fertilizer production, scale is a key factor; the current scale for such production should be over 300,000 tons. In China, the scale of large-scale fertilizer production is 450,000 tons of synthetic ammonia. 2. The main advantage of new manufacturing processes lies in their lower energy consumption levels; currently, the lowest energy consumption rates in the international arena are around 28–29 GJ. 3. As for synthetic ammonia production using coal as raw material, the more advanced processes available internationally include Texaco’s water-coal slurry process and Shell’s pulverized coal gasification process. The issue with these processes is their high initial investment costs. However, due to the significant cost advantages associated with coal as a raw material, many gasification units have been installed in China. The biggest challenges faced by these operating gasification units are system stability and long-term operational continuity. It should be noted that there is a significant difference between the designed energy consumption and the actual energy consumption of a unit, and this is closely related to the unit’s ability to operate continuously and stably.

How did the discussion question end up in the materials section?

I agree with the view from the 6th floor; thank you for helping to solve the problem!

28–29 GJ seems to be the comprehensive energy consumption for gas-based processes; what is the figure for ammonia synthesis using coal? Please give me some advice!

The main advantage of the coal-based ammonia synthesis process lies in the low cost of its raw materials; however, its energy consumption is relatively high. Currently, Shell’s energy consumption seems to be lower, around 43 GJ, while Texaco’s is around 46 GJ, and the Ruchi process has an energy consumption of approximately 49 GJ. My data might not be accurate, as I haven’t checked the relevant materials for a long time

1. Generally, a medium- to low-pressure ammonia synthesis plant in which a single set of systems is capable of producing 300,000 tons per year of ammonia and 520,000 tons per year of urea, with a design pressure of 15.0 MPa, is considered a large-scale nitrogen fertilizer plant. The raw material sources for large-scale fertilizers used to be natural gas, residue oil, etc.; nowadays, the powder coal gasification process is also employed ； The purification of feed gas is mostly carried out using cold methods, though methanation processes are also employed. The feed gas compressor is of centrifugal steam-driven type, with the overall power consumption per ton of ammonia in the plant being around 5 KWH. Most of the technology is imported from abroad! 2. Medium nitrogen: According to the original definition, there were perhaps 56 such facilities nationwide at that time; they used natural gas, coal, or oil as raw materials, with a synthesis ammonia production pressure of 31.4 MPa. Reciprocating compressors were used, and copper washing or methanation processes were employed for the purification of the raw gas. The gas generation furnaces had a diameter of over φ3000, and most of the technology related to synthesis ammonia was provided by domestic suppliers. Now, many small nitrogen plants have surpassed medium-sized nitrogen plants in scale. 3. The original production capacity of Xiaonitrogen ranged from 3,000 to 15,000 tons; its equipment and production processes were the same as those of Zhongnitrogen. Initially, there were around 1,600 such facilities, but now only over 600 remain. But many have a scale exceeding medium nitrogen, and their total ammonia production can exceed that of large nitrogen plants!

First, the production capacity is higher than that of traditional systems. Second, for large-scale equipment, there are no backup units for the core equipment； Third is energy-saving.