Comparison of driving options and choice of how to drive

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Comparison of driving plans and selection of driving methods Company: I. Currently, the company has only 8,000 tons of sulfur, and it needs to be transported over 45 days – how should this transportation be carried out? The branch factory has put forward several options for the company’s management to decide on. Option 1: (1) Operate the steam blower for 20 days, with a daily acid production of 750 tons and a sulfur consumption of 5,000 tons ； (2) The electric fan was operated for 25 days; during those days, the daily production volume was 450 tons for 20 days, with a sulfur consumption of 3,000 tons ； With a daily production of 300 tons over 5 days (operating in two shifts), 500 tons of sulfur are consumed; the total amount of sulfur used is thus 8,500 tons. The shortage of sulfur is more than 500 tons, so an additional 1,000 tons of sulfur need to be purchased to ensure that the electric fans can keep running for 25 days (with a daily production of 450 tons). Economic benefits of Option 1: (1) Direct economic losses (extra electricity costs): 1900 KWH × 24 hours × 0.50 yuan/kWh × 25 days = 570,000 yuan. (2) Economic benefits of purchasing sulfuric acid: The current cost of producing sulfuric acid is 1580.00 yuan/ton × 0.333 tons + 60 kWh × 0.50 yuan/kWh + 3.72 yuan/ton + 3.00 yuan/ton + depreciation cost of 30.00 yuan/ton, resulting in a total cost of 593.89 yuan/ton; whereas the cost of purchasing sulfuric acid from Yun Copper is 420 yuan/ton ； 150 tons/day × (593.89–420) × 25 days = 652,100 yuan. The total economic benefit is: 652,100 – 570,000 = 82,100 yuan. Option 2: Do not operate the steam fans now, but operate the electric fans. Acid production per day: 500 tons; sulfur consumption: 500÷3×45=7500 tons ； Under this plan, sulfur will no longer be purchased. However, the losses incurred are as follows: (1) Direct economic loss (electricity cost): 1900 KWH × 24 hours × 0.50 yuan/kWh × 45 days = 1.0125 million yuan. (2) Loss in direct labor costs (wage subsidies): (750–500 tons/day) × 3.72 yuan/ton × 45 days = 41,850 yuan. (3) The economic losses resulting from not producing concentrated phosphoric acid have not been calculated ； (4) Economic benefits of purchasing sulfuric acid: The current cost of producing sulfuric acid is 1580.00 yuan/ton × 0.333 tons + 60 kWh × 0.50 yuan/kWh + 3.72 yuan/ton + 3.00 yuan/ton, plus depreciation costs of 30.00 yuan/ton, resulting in a total cost of 593.89 yuan/ton. In contrast, the cost of purchasing sulfuric acid from YunTong is 420 yuan/ton ； 150 tons/day × (593.89–420) × 45 days = 1,173,760 yuan. The total economic benefit is: 1.17376 million – 0.04185 million – 1.0125 million = 0.11941 million. Option 3: Use steam fans to operate the entire 8,000 tons of sulfur, after which the sulfuric acid system is shut down; it will be restarted once more sulfur is available. Economic benefits of this solution: (1) The use of steam exhaust fans can help save on electricity costs: 8,000 tons ÷ 250 tons/day × 750 tons/day × 47.15 = yuan per ton = 1.1316 million yuan. (2) Startup and shutdown ignition costs: (1) Diesel: 25 tons × 6,000 yuan/ton = 150,000 yuan ； Above (2): Labor costs: 75 people × (3 days driving + 13 days not driving) × 40.00 yuan/day = 48,000 yuan. (3) Diesel cost for parking: 15 tons × 6,000 yuan/ton = 90,000 yuan. (4) Electricity cost for starting and stopping the machine: 3,886.55 KW × 48 hours × 0.50 yuan/kWh = 93,300 yuan ； (5) Coal consumption for starting up the boiler: 3 days × 48 tons/day × 550.00 yuan/ton = 79,200 yuan. (6) Economic benefits of purchasing sulfuric acid: The current cost of producing sulfuric acid is 1580.00 yuan/ton × 0.333 tons + 60 kWh × 0.50 yuan/kWh + 3.72 yuan/ton + 3.00 yuan/ton + depreciation cost of 30.00 yuan/ton, which amounts to 593.89 yuan/ton; whereas the cost of purchasing sulfuric acid from Yun Tong is 420 yuan/ton ； 150 tons/day × (593.89–420.00) × 15 days = 391,250 yuan. The total economic benefit is: 39.125 + 113.16 – 15 – 4.8 – 9.0 – 9.33 – 7.92 = 1,062,350 yuan. Note: The impact of the lack of hot air due to the shutdown of the sulfuric acid plant on the economic benefits of calcium dihydrogenide and calcium hydride has not been calculated. II. Comparison table of power consumption, steam production volume, and hot air temperature for the electric fans and steam fans used in sulfuric acid production:
Date | Acid production (t/year) | Daily power consumption (KWh) | Power consumption per ton of acid (kWh/ton) | Steam production per hour (t/h) | Steam consumed for melting sulfur (t/h) | Steam consumed by the deaerator (t/h) | Hot air temperature (°C)
June 9 | 450.95 | 65,020 | 146.79 | 13–14 | 4–5 | 2–3 | 400–430
June 14 | 441.8 | 72,090 | 163.17 | 13–14 | 4–5 | 2–3 | 400–430
June 15 | 470.18 | 62,960 | 133.91 | 15 | 4–5 | 2–3 | 400–430
Total (electric fans) | 1,362.93 | 200,070 | 146.79 | 14.5 | 4–5 | 2–3 | 415

For the steam fans:
June 17 | 40,080 | 26 | 4–5 | 4.2–4.5 | 320–340
June 18 | 778.65 | 39,840 | 26 | 4–5 | 4.35 | 320–340
June 19 | 39,660 | 50.93 | 26–27 | 4–5 | 4.35 | 320–340
Total (steam fans) | 226,893 | 119,580 | 52.70 | 26.5 | 4–5 | 4.35 | 320–340

1. The electric fans consume more electricity than the steam fans: 146.79 – 52.7 = 94.09 kWh per ton of acid. The additional cost associated with this higher power consumption is 0.5 × 94.09 = 47.045 yuan per ton of acid. (Theoretical calculation of electricity consumption and cost per ton of acid: 1920 KWh × 24 ÷ 450 t/a × 95% = 97.28 kWh per ton of acid, 48.64 yuan per ton of acid). This plan calculates the electricity cost based on the motor’s full-load output. 2. Depreciation cost per ton of acid: 80 million yuan × (1 – 5%) ÷ 8 years ÷ 300,000 tons per year = 31.67 yuan per ton of acid; in this plan, the depreciation cost is calculated at 30.00 yuan per ton of acid. 3. The average electricity cost is calculated at 0.50 yuan per kilowatt-hour. 4. Steam generator fan: Acid production volume: around 750 tons per day; steam generation rate: 26–27 t/h. Steam consumption for sulfur melting in the branch plant: 4–5 t/h ； Deaerator steam consumption: 4.35 t/h ； The temperature of the heated air is: 320–340°C. The sulfuric acid system operates in a two-stage reaction and two-stage absorption process. The minimum acid production per day at the start-up of the steam blower is 750 tons. 5. Power-driven fan: Acid production volume: around 450 tons per day; steam generation rate: 13–14 t/h. Steam consumption for sulfur melting in the branch plant: 4 t/h ； Deaerator steam consumption: 2–3 t/h ； The temperature of the heated air is: 430–450°C. The sulfuric acid system operates in a one-turn-one-suction process. 6. From the perspective of maximum economic benefit, the company can consider the third option ； From the perspective of stabilizing the workforce and protecting equipment: both Option 1 and Option 2 are viable. (Option 3 is the best, followed by Option 1, and then Option 2.) ) Sulfuric Acid Plant: lchy, evening of June 21, 2007