Compare three types of nitrogen on the market (bottled nitrogen, liquid nitrogen, and nitrogen generator) using 50Nm ³/h as an example
1. The operating cost of bottled nitrogen
According to the market, the price of nitrogen with a purity of 99999% is 100 yuan per bottle. The standard volume of a bottle of nitrogen under a pressure of 12Mpa is 40 liters, but in reality, each bottle is only about 5M3. Therefore, the price of ordinary nitrogen per cubic meter is about 20 yuan. This gas usage method is only suitable for users with very low gas consumption.
The annual usage fee for theoretical 50Nm ³/h nitrogen consumption is 8 million yuan/year, which is 50 × 20 × 8000.
2. The operating cost of liquid nitrogen
The wholesale price of liquid nitrogen with a purity of 99.999% on the market is 1200 yuan/ton. One ton of liquid nitrogen can theoretically vaporize to obtain about 840 cubic meters of gaseous nitrogen (actual working conditions can only vaporize 800 cubic meters), and the price of nitrogen per cubic meter is about 1.5 yuan. (Excluding the initial investment in liquid nitrogen storage tanks, vaporizers, annual maintenance, and labor costs)
The cost of using liquid nitrogen: 50Nm3/h x 1.5 yuan=75 yuan/hour
Annual usage cost: 75 × 8000 hours/year=600000 yuan/year
3. Operating cost of on-site nitrogen production (calculated based on a complete nitrogen production system of 50Nm3/h)
The operating cost of the system mainly consists of the following aspects:
1. Consumption of electrical energy
2. Artificial
3. Equipment maintenance costs
4. Depreciation of equipment
The consumption of electricity mainly comes from the following aspects:
Air compressor: The rated power of the air compressor is 37kw. Because the unloading of the air compressor and appropriate compressed air margin are considered during system selection, the actual power consumption of the air compressor is about 80% of the rated power (power frequency machine), which is about 29.6kw.
Freeze dryer: The rated power of the freeze dryer is 1.5kw.
Nitrogen generator: The raw material of the nitrogen generator is compressed air, and the nitrogen generator itself does not consume much electricity. It is mainly used for instrument power, with a rated power of about 0.2kw. Overall, the power consumption of the entire nitrogen generator system is 31.7kw
Assuming the electricity cost is 1 yuan/kWh, the hourly power consumption is 31.7 × 1=31.7 yuan
Equivalent to power consumption per cubic meter of finished nitrogen: 31.7 ÷ 50=0.63 yuan/cubic meter
Usage fee: 50Nm3/h x 0.63 yuan=31.5 yuan/hour (electricity fee)
Annual usage fee: 31.5 × 8000 hours/year=252000 yuan/year (electricity fee)
Labor cost: As the equipment does not require dedicated personnel, only regular and irregular inspections are required Equipment maintenance and upkeep costs:
The maintenance and upkeep costs of the entire machine are mainly reflected in:
Air compressor
Air filter cartridge: replace every 4000 hours Unit price: 420 yuan/piece
Oil and gas filter element: replace every 3000 hours Unit price: 400 yuan/piece
Oil separation core: replaced every 3000 hours Unit price: 980 yuan/piece
Lubricating oil: replace every 3000 hours Unit price: 1200 yuan/time
Maintain twice a year Total annual cost: (420+400+980+1200) × 2=6000 yuan, average to 0.75 yuan/hour; Compressed air filter C, T, A, X four stage filtration
Replace every 4000 hours: 400/4 pieces
Nitrogen generator: Nitrogen analyzer probe: to be replaced every two years Unit price: 1200 yuan/piece
Total annual cost: 2800 yuan, average hourly rate: 0.35 yuan/hour
Depreciation cost of equipment: The depreciation period of equipment is ten years
4. Nitrogen production system PD5N-50Nm3/h
1. The cost of using nitrogen cylinders:
The annual usage fee for a theoretical nitrogen consumption of 30Nm ³/h is 8 million yuan per year. (Excluding rental costs for the upfront investment of busbar equipment, pressure reducing valves, and steel cylinders)
2. The cost of using liquid nitrogen:
The cost of using liquid nitrogen: 50Nm3/h x 1.5 yuan=75 yuan/hour
Annual usage cost: 75 × 8000 hours/year=600000 yuan/year (excluding the cost of upfront investment in busbar equipment, pressure reducing valves, container rental, and vaporizer)
3. Cost of nitrogen production system:
Electricity fee+equipment maintenance fee+equipment depreciation fee
Annual usage fee: 252000 yuan/year (electricity fee)+7600 yuan/year (maintenance fee)+13000 yuan/year (depreciation fee)=272600 yuan/year.
In summary: Calculated based on 5 years of use: Steel cylinder cost: not considered (cost too high)
Liquid nitrogen cost: 3 million (too high cost)
PSA nitrogen production system: 1.363 million (recommended)
