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Release Characterization

Release Characterization. Case Study. Major Emission Sources. Venting from the feed and product storage tanks Off-gases from the scrubbers Liquid wastes from the scrubbers Emissions from the decanting and purification columns Emissions from the boilers Fugitive emissions

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Release Characterization

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  1. Release Characterization Case Study

  2. Major Emission Sources • Venting from the feed and product storage tanks • Off-gases from the scrubbers • Liquid wastes from the scrubbers • Emissions from the decanting and purification columns • Emissions from the boilers • Fugitive emissions • Feed and product loading and off-loading emissions

  3. Emission from Reactors, Stripper, Decanting and Purification Columns • Table 8.3-2: 1.5kg/1000 kg throughput (reactor vent), 0.2 kg/1000 kg throughput (stripper), 0.02 kg/ 1000 kg throughput (decanter), 0.7 kg/ 1000 kg throughput (distillation column vents). • Assume (1) half of the emissions from reactor are cyclohexane (reactant) and half are ketone and alcohol (products) and (2) all of the emissions of the other units are products. • Emission estimates: 0.8 kg cyclohexane/ 1000 kg throughput and 1.6 kg ketone and alcohol/100 throughput.

  4. Emissions from Boilers • Rudd et al. (1981) suggested 1 value of 0.5 metric tons of fuel oil used per metric ton of product. • Assume #6 fuel oil with 1% sulfur is used.

  5. Fugitive Emissions • Rough estimates are made on the basis of experience. Typical values: 0.5 – 1.5 kg per 1000 kg product. • Use 0.5 kg/ 1000 kg throughput. • Emissions are evenly split between products and reactants.

  6. Emission Loss from Liquid Loading

  7. Losses from Tanks • Assume an annual production rate of 100 million pounds per year. • A typical tank should hold 2-3 days of production capacity. • A tank 35 ft in diameter and 20 ft high with a fixed roof is reasonable. • The tank is 80% full. • If the facility is located in Houston, TX, the data and procedure described in appendix C lead to an estimate of 0.5 kg emitted/1000 kg product for standing and working losses. • We will assume that these are emissions of the feed material (cyclohexane) also.

  8. Hedley et al. (1975)

  9. Environmental Performance

  10. Performance Indicators • Energy consumed from all sources within the manufacturing or delivery process per unit of manufactured output. • Total mass of material used directly in the product, minus the mass of the product, per unit of manufactured output. • Water consumption per unit of manufactured product. • Emissions of targeted pollutants (those listed in TRI) per unit of manufactured output. • Total pollutants per unit of manufactured output.

  11. Material Use Based on data of Rudd et al. (1981) and Hedley et al. (1975). Rudd reports that the manufacture of 1 ton of cyclohexanol requires 1.64 tons of cyclohexane and 0.13 ton of NaOH. Cyclohexanone is produced at a rate of 0.38 tons per tons of cyclohexanol.

  12. Water Use • According to Hedley et al. (1975), 5000 gpm of cooling water and 10 gpm of process water are used for a 85000000 pounds per year facility. • This leads to an estimate of 30 gallons of water per pound of product.

  13. Energy Intensity and Pollutant Generation • From literature, 0.4 fuel oil per kg product. On the basis of 150000 BTU per gallon fuel oil, the energy intensity is 7 kBTU per pound of product. • From Table 8.3-12, pollutant generation is 0.3 lb/ lb product.

  14. The performance indicators of the example process are at the high ends of the range reported here. Improvements are needed!!!

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