Problems after the improvement of the ammonia synthesis tower
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Our plant currently has 1000mm single-tube baffled short towers, and we want to replace them with internals of 1000mm diameter with two shafts. There are currently 3 circulation pumps with an air injection capacity of 2 cubic meters per minute (two of them are operating continuously). Is the current configuration reasonable after this modification, and is the air injection capacity of the circulation pumps sufficient?
I’m not sure what level of ammonia production you are aiming for; in a radial tower, the net ammonia yield is generally only around 10%. The hourly ammonia production can be calculated by multiplying this net ammonia yield by the circulation rate (in units per hour), by the pressure, divided by 22.4, and then multiplied by 17. If the ammonia synthesis output is 60,000 tons, the synthesis pressure is 240 kg, and the circulation volume is approximately 7.6 m3; 5 m3 are required for 40,000 tons of ammonia synthesis. 2 2m3 circulation machines might be too small.
Thank you, second floor； After the technical upgrades, the production volume is aimed at 40,000–50,000 tons. Can the air delivery volume of the cycle machine be increased to 2.4 cubic meters per minute by enlarging its cylinders?
We have a 1000 model synthesis tower here; when replacing the catalyst, we use two 4-cubic-meter circulation pumps. Now, at the end of the catalyst’s lifespan, we still use one 4-cubic-meter pump and one 1.8-cubic-meter pump. Moreover, our production volume has not yet reached its maximum level, with a synthesis pressure of 24 MPa. I think you should install another 4-cubic-meter circulation pump – otherwise, it might affect the effectiveness of the renovation
Configuration of the recirculator: An empirical approach – a recirculator of 1 m3 per minute is suitable for an ammonia production capacity of 10,000 tons per year. You are short and plump ammonia synthesis towers with a production capacity of over 40,000 tons; a 4 m3 circulation pump is a bit too small for you.
We are from Shanghai Jiading Circulating Machine Factory; our machines have a capacity of 1.9 m3 and 285 kW, with an original cylinder diameter of 102 mm that can be increased up to 110 mm, resulting in an air volume of 2.2 m3. Increasing it from 2m3 to 2.4m3 – just increasing the cylinder diameter might not be sufficient; raising the rotation speed a bit should work, but it’s necessary to consult the manufacturer.
To increase the cylinder diameter, it is necessary to calculate the piston force and motor power, as well as to verify the components; as long as these calculations are satisfactory, it is feasible to do so. The same applies to increasing the rotation speed – calculations must be taken into account!
Based on experience, with 310 production days per year, 1 cubic meter of circulation volume is allocated to produce 10,000 tons of synthetic ammonia
Thank you all, dear friends: Our factory has 2 sets of systems, and this time our goal is to increase output per unit and reduce consumption. By enlarging the cylinder of the circulation machine and increasing the motor power, the manufacturer believes that these measures can meet our requirements; we hope it will succeed.
This issue depends on the content of inert gases in your fresh gas, as well as the content of inert gases in the bleed gas; these are important factors that affect the pumping capacity of the cycle machine.