That teacher is familiar with the material balance in the chlorine drying section of ion-exchange membrane caustic soda production
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This post was last edited by sunjl1981 on 2013-1-6 23:39. Urgently need the material balance data for the chlorine washing and drying stage in ion-exchange membrane caustic production. For example, what proportion of impurities is present in the chlorine gas coming out of the electrolyzer, and how is the spraying volume of chlorinated water calculated in the chlorine gas scrubber? # + + .
There are calculation sheets on chlorine drying (material balance for chlorine water scrubbers) on the forum; you can search for them by yourself
Could you please send the link to this forum at tcs1789@163.com??
(Note): I forgot that link address from someone else’s post on another forum; it’s related to the calculation sheet for the drying process. I. Heat balance calculation for the chlorine scrubber: 1. The calculation is based on the production of 1 ton of 100% NaOH. 2. The chlorine temperature at the inlet of the tower is 80°C, while the temperature at the outlet is 40°C; the pressure is 101.225 KPa ； The temperature of the chlorine water leaving the tower is 50°C. 3. The water content in the gas entering the tower is given by: (W_water/18)/(88**/71) = 47.4/(101.225–47.4). According to Dalton’s law of partial pressures, 47.4 represents the saturated vapor pressure of water at 80°C. Thus, W_water = 198.142 kilograms.
4. The components of the gas entering the tower are as follows: dry chlorine gas – 88** kilograms (12.5 Kmol); other gases – 15 kilograms (0.5172 Kmol); water – 198.14 kilograms (11.01 Kmol). When converted to an annual production volume of 60,000 tons of 100% NaOH (with a production time of 8,000 hours), the components of the gas entering the tower become: dry chlorine gas – 6656.25 kilograms (93.75 Kmol); other gases – 112.5 kilograms (3.88 Kmol); water – 1486.07 kilograms (82.56 Kmol).
5. For the gas exiting the tower, the saturated vapor pressure of water at 40°C is 7.37 KPa. Therefore, W_water = 17.67 kilograms. The amount of water vapor that can be cooled in the scrubber is 198.142–17.67 = 180.372 kilograms. At 50°C, the solubility of chlorine gas is 0.003925 kg/kg. Hence, the amount of chlorine gas lost is 180.372×0.003925 = 0.7084 kilograms. Converting this to an annual production volume of 60,000 tons of 100% NaOH, the total amount of chlorine gas lost is 0.7084×60,000/8,000 = 5.313 kilograms. The components of the gas exiting the tower under these conditions are: dry chlorine gas – 6650.95 kilograms (93.68 Kmol); other gases – 112.5 kilograms (3.88 Kmol); water – 132 kilograms (7.3 Kmol).
6. Heat carried in by the gas entering the scrubber: At 80°C, the specific heat capacity of chlorine gas is 8.364 kcal/mol·°C. The enthalpy of water vapor at 80°C is 631.4 kcal/kg. The specific heat capacity of other gases at 80°C is 6.9 kcal/mol·°C. The heat carried in by dry chlorine gas is Q_Cl2 = 93.75×8.364×80 = 62730 kcal. The heat carried in by wet chlorine gas due to its water content is Q_H2O = 631.4×1486.07 = 938304 kcal. The heat carried in by other gases is Q = 6.9×3.88×80 = 2141.8 kcal. The total heat carried in by the gas is ∑Q = 62730 + 938304.6 + 2141.8 = 1,003,175.8 kcal.
7. Heat carried out by the gas exiting the scrubber: At 40°C, the specific heat capacity of chlorine gas is 8.3 kcal/mol·°C. The enthalpy of water vapor at 40°C is 613.64 kcal/kg. The specific heat capacity of other gases at 40°C remains 6.9 kcal/mol·°C. The heat carried out by dry chlorine gas is Q_Cl2 = 93.66×8.3×40 = 31,095.12 kcal. The heat carried out by wet chlorine gas due to its water content is Q_H2O = 613.64×132 = 81,000.48 kcal. The heat carried out by other gases is Q = 6.9×3.88×40 = 1,070.88 kcal. The heat carried out by the chlorine-containing solution is Q = (1486–132+5.313)×50×1 = 67,965.65 kcal. The total heat carried out by the gas is ∑Q = 31,095 + 81,000.48 + 1,070.88 + 67,965.65 = 181,139.93 kcal. The amount of heat removed by the chlorine-containing solution spray is Q_in – Q_out = 1,003,175.8 – 181,139.93 = 822,035.87 kcal.
II. Calculation of the amount of chlorine-containing solution required for spraying: The spraying temperature of the chlorine-containing solution should be kept below 37°C, and the temperature at the outlet of the scrubber should be below 50°C. The heat transfer equation is: Q = 50×1×q_flow – 37×1×q_flow. Solving for q_flow gives 63,233.53 kilograms per hour, or 63.233 m³ per hour. The diameter of the chlorine-water circulation pipe is 0.122 meters (assuming a flow velocity of 1.5 m/s). Rounding up, a DN125 pipe is used. III. Calculation of the chlorinated water plate heat exchanger 1. Calculation of the area of the chlorinated water plate heat exchanger: The spraying rate of chlorinated water is 63.233 m3/h; the temperature of the circulating water entering the exchanger is 35°C, while that of the returning water is 39°C. The heat transfer quantity Q is given by the formula Q = K * A * Δt, where K = 2500 and Δt = {(T1 – t2) – (T2 – t1)} / ln{(T1 – t2) / (T2 – t1)} = 5.2793. Therefore, Q = 2500 * 5.2793 * A, which gives A = 62.28 m2. The heat transfer capacity specified by the manufacturer for this chlorinated water plate heat exchanger is 700,000 kJ/h, which is approximately 167,000 kcal/h. 2. Flow rate of circulating water: The volume of circulating water V = Q/heat / (39 – 34) × 1 = 822029/4 = 164405 = 164.405 m³/h. The diameter of the circulating water pipe d = 0.197 meters (with a flow velocity of 1.5 m/s for the circulating water); thus, the pipe diameter is rounded to DN200, so DN200 is chosen.
IV. Calculation of the titanium cooler:
1. Heat balance: The temperature of the water entering the cooler is 40°C, while it exits at 12°C. The temperature of the chlorine water is 15°C. The heat carried into the cooler by the gaseous components is 113174 kilocalories. At 12°C, the saturated vapor pressure of water is 1.71 KPa; therefore, W_water = 28.949 kilograms (based on an annual production of 60,000 tons of 100% caustic soda). The solubility of chlorine gas at 15°C is 0.008495 kilograms per kilogram of water. Thus, the amount of chlorine gas lost is (132 – 28.949) × 0.008495 = 0.9218 kilograms. The amount of chlorine water produced is 132 – 28.949 + 0.9218 = 103.9728 kilograms. The heat carried away by the gaseous stream exiting the cooler is as follows: The specific heat of chlorine gas at 12°C is 8.214 kilocalories/Kmol·°C, the enthalpy of water vapor is 602.6 kilocalories/kilogram, and the specific heat of other gases is 6.9 kilocalories/Kmol·°C. The heat carried away by dry chlorine gas is QCl2 = 93.66 × 8.214 × 12 = 9233.85 kilocalories. The heat carried away by wet chlorine gas containing water is QH2O = 602.64 × 28.949 = 17444.26 kilocalories. The heat carried away by other gases is Q = 6.9 × 3.88 × 12 = 321.64 kilocalories. The heat removed by the chlorine water is Q = 103.9728 × 1 × 15 = 1559.59 kilocalories. In total, ∑Q_out = 9233 + 17444.26 + 321.64 + 1559.59 = 28558.24 kilocalories. The heat carried away by the chilled water is Q_in – Q_out = 113173.8 – 28558.24 = 84615.56 kilocalories.
2. Calculation of the heat exchange area of the cooler: The inlet temperature of the chilled water is 8°C, and the outlet temperature is 11°C. The inlet temperature of chlorine gas to the titanium cooler is 40°C, and the outlet temperature is 12°C. Δt = {(T1 – t2) – (T2 – t1)} / ln{(T1 – t2) / (T2 – t1)} = {(40 – 11) – (12 – 8)} / ln{(40 – 11) / (12 – 8)} = 12.62. Heat transfer rate Q = K × A × Δt. With K = 100 and A = Q/Δt × K = 84615 / (12.62 × 100) = 67.05 m².
3. Calculation of the amount of chilled water required: The volume of chilled water needed V = Q / (11 – 8) × 1 = 84615 / (11 – 8) = 28206.3 m³/h = 28.206 m³/h. The diameter of the chilled water pipe is 0.081 meters (with a flow velocity of 1.5 m/s for the chilled water); thus, the pipe diameter is rounded to DN100, so DN100 is chosen.
V. Calculation of the diameter of the acid pipes: In towers I, II, and III, the amount of sulfuric acid sprayed is 50 m³/h each. Therefore, the diameter d = 0.109 meters (with a flow velocity of 1.5 m/s for the sulfuric acid). The pipe diameter is rounded to DN125, so DN125 pipes are used. Ⅲ For the filler drying tower, the acid addition rate is 100 L/h, and a pipe with a diameter of DN25 is used. VI. Calculation of the sulfuric acid heat exchanger 1. The heat transfer capacity of the plate heat exchanger used in Tower I’s filler drying tower is 200,000 kJ/h (provided by Hangzhou Dongri Company), which is equivalent to approximately 47,619 kcal/h. Therefore, the amount of chilled water required for the plate heat exchanger in Tower I is as follows: the inlet temperature of the chilled water is 8°C, the outlet temperature is 11°C, and the flow rate of the chilled water is 1.5 meters per second. The specific heat capacity of water is 1 kcal/kg. ℃Using the formula W×CP×(T2-T1)＝Q, we obtain W＝Q/〈CP×(T2-T1) 〉. Thus, W＝47619/〈1×(11-8) 〉＝15873 kilograms/hour＝15.873 m3/hour. The diameter of the pipe for the chilled water is d＝0.061 meters; rounding this value gives DN65, so a DN65 pipe is used. Ⅰ. For the calculation of the area of the sulfuric acid plate heat exchanger in the packed drying tower, given that the inlet temperature of sulfuric acid is 16°C and the outlet temperature is 12°C, △t = { (T1 – t2) – (T2 – t1) } / ln{ (T1 – t2) / (T2 – t1) }. Thus, △t = { (16 – 11) – (12 – 8) } / ln{ (16 – 11) / (12 – 8) } = 4.48. The heat transfer rate Q is calculated as Q = K * A * △t; where K = 1500, and A = Q / (K * △t) = 47619 / (1500 * 4.48) = 7.086 m².
2. The heat transfer rates for the plate heat exchangers in packed drying towers II and III are both 79,000 kJ/h (provided by Hangzhou Dongri Company), which is approximately 18,810 kcal/h. The amount of chilled water required for each of these heat exchangers is W = 18,810 / <1 × (11 – 8)> = 6,270 kilograms/h, or 6.270 m³/h. The diameter of the chilled water pipes is d = 0.038 m; rounding this value up gives DN50, so DN50 pipes are used. II. Calculation of the area of the sulfuric acid plate heat exchanger in the filler drying tower: Given that △t = 4.48 and K = 1500, then A = Q/(K*△t) = 18810/(1500*4.48) = 2.799 m2. 3. The heat transfer rate required for the acid replenishment plate heat exchanger in the filler drying tower is 15,000 kJ/h (provided by Hangzhou Dongri Company), which is approximately 3,571 kcal/h. The amount of chilled water needed is W = 3571/〈1×(11–8)〉 = 1,190 kg/h = 1.19 m3/h. The diameter of the chilled water pipes is d = 0.017 m; rounding this value to the nearest standard size gives DN25, so DN25 pipes are used. Ⅲ Calculation of the area of the plate heat exchanger for acid addition in the filler drying tower: Given Δt = 4.48 and K = 1500, then A = Q/(K*Δt) = 3571/(1500*4.48) = 0.531 m2. Calculation of the diameter of the main pipe for chilled water: The total volume of chilled water is 28.3 m3/h from the titanium cooler, plus (15.9 + 7.1 + 6.3 + 1.2) m3/h from the sulfuric acid coolers, resulting in a total of 58.9 m3/h. With a flow rate of chilled water of 1.5 m/s, the pipe diameter d = 0.117 m; rounding this value gives DN125, so a DN125 pipe is used. VII. Calculation of the diameter of the chlorine pipe entering the chlorine washing tower. Under standard conditions (1 atm, 0°C), 1 mole of gas equals 22.4 m³ of gas. The number of moles of chlorine entering the tower per hour is as follows: the number of moles of dry chlorine is 93.75 mol, the number of moles of water vapor is 82.56 mol, and the number of moles of other gases is 3.88 mol. The volumetric flow rate of the gas at the inlet of the washing tower under standard conditions is V = (93.75 + 82.56 + 3.88) * 22.4 = 180.89 * 22.4 = 4036 m³/h. Given that the temperature of the chlorine before it reaches the washing tower is 80°C and the pressure is –0.5 KPa, the actual flow rate is V = 4036 * … = 5244 m³/h. The diameter d of the main chlorine pipe is calculated as follows: d = … = 0.393 (with a chlorine flow velocity of 12 m/s). Rounding up, the pipe diameter is set to DN400; thus, a DN400 pipe is used. VIII. Calculation of the diameter of the outlet pipe of the scrubber tower: The number of moles of gas exiting the scrubber tower is as follows – 93.66 moles of dry chlorine gas, 7.33 moles of water vapor, and 3.88 moles of other gases. The volumetric flow rate of these gases at standard conditions is given by V = (93.66 + 7.33 + 3.88) * 22.4 = 2349.09 m³. Given that the temperature of the chlorine gas at the outlet of the scrubber tower is 40°C and the pressure is –1.5 KPa, the actual flow rate is V = 2349.09 * … = 2731 m³. The diameter d of the main pipe for the chlorine gas at the outlet of the scrubber tower is calculated to be 0.311 meters (assuming a flow velocity of 10 m/s for the chlorine gas). Rounding this value up, the appropriate pipe diameter is DN350; hence, a DN350 pipe should be used.
4. The components of the gas entering the tower are as follows: dry chlorine gas – 88** kilograms (12.5 Kmol); other gases – 15 kilograms (0.5172 Kmol); water – 198.14 kilograms (11.01 Kmol). When converted to an annual production volume of 60,000 tons of 100% NaOH (with a production time of 8,000 hours), the components of the gas entering the tower become: dry chlorine gas – 6656.25 kilograms (93.75 Kmol); other gases – 112.5 kilograms (3.88 Kmol); water – 1486.07 kilograms (82.56 Kmol).
5. For the gas exiting the tower, the saturated vapor pressure of water at 40°C is 7.37 KPa. Therefore, W_water = 17.67 kilograms. The amount of water vapor that can be cooled in the scrubber is 198.142–17.67 = 180.372 kilograms. At 50°C, the solubility of chlorine gas is 0.003925 kg/kg. Hence, the amount of chlorine gas lost is 180.372×0.003925 = 0.7084 kilograms. Converting this to an annual production volume of 60,000 tons of 100% NaOH, the total amount of chlorine gas lost is 0.7084×60,000/8,000 = 5.313 kilograms. The components of the gas exiting the tower under these conditions are: dry chlorine gas – 6650.95 kilograms (93.68 Kmol); other gases – 112.5 kilograms (3.88 Kmol); water – 132 kilograms (7.3 Kmol).
6. Heat carried in by the gas entering the scrubber: At 80°C, the specific heat capacity of chlorine gas is 8.364 kcal/mol·°C. The enthalpy of water vapor at 80°C is 631.4 kcal/kg. The specific heat capacity of other gases at 80°C is 6.9 kcal/mol·°C. The heat carried in by dry chlorine gas is Q_Cl2 = 93.75×8.364×80 = 62730 kcal. The heat carried in by wet chlorine gas due to its water content is Q_H2O = 631.4×1486.07 = 938304 kcal. The heat carried in by other gases is Q = 6.9×3.88×80 = 2141.8 kcal. The total heat carried in by the gas is ∑Q = 62730 + 938304.6 + 2141.8 = 1,003,175.8 kcal.
7. Heat carried out by the gas exiting the scrubber: At 40°C, the specific heat capacity of chlorine gas is 8.3 kcal/mol·°C. The enthalpy of water vapor at 40°C is 613.64 kcal/kg. The specific heat capacity of other gases at 40°C remains 6.9 kcal/mol·°C. The heat carried out by dry chlorine gas is Q_Cl2 = 93.66×8.3×40 = 31,095.12 kcal. The heat carried out by wet chlorine gas due to its water content is Q_H2O = 613.64×132 = 81,000.48 kcal. The heat carried out by other gases is Q = 6.9×3.88×40 = 1,070.88 kcal. The heat carried out by the chlorine-containing solution is Q = (1486–132+5.313)×50×1 = 67,965.65 kcal. The total heat carried out by the gas is ∑Q = 31,095 + 81,000.48 + 1,070.88 + 67,965.65 = 181,139.93 kcal. The amount of heat removed by the chlorine-containing solution spray is Q_in – Q_out = 1,003,175.8 – 181,139.93 = 822,035.87 kcal.
II. Calculation of the amount of chlorine-containing solution required for spraying: The spraying temperature of the chlorine-containing solution should be kept below 37°C, and the temperature at the outlet of the scrubber should be below 50°C. The heat transfer equation is: Q = 50×1×q_flow – 37×1×q_flow. Solving for q_flow gives 63,233.53 kilograms per hour, or 63.233 m³ per hour. The diameter of the chlorine-water circulation pipe is 0.122 meters (assuming a flow velocity of 1.5 m/s). Rounding up, a DN125 pipe is used. III. Calculation of the chlorinated water plate heat exchanger 1. Calculation of the area of the chlorinated water plate heat exchanger: The spraying rate of chlorinated water is 63.233 m3/h; the temperature of the circulating water entering the exchanger is 35°C, while that of the returning water is 39°C. The heat transfer quantity Q is given by the formula Q = K * A * Δt, where K = 2500 and Δt = {(T1 – t2) – (T2 – t1)} / ln{(T1 – t2) / (T2 – t1)} = 5.2793. Therefore, Q = 2500 * 5.2793 * A, which gives A = 62.28 m2. The heat transfer capacity specified by the manufacturer for this chlorinated water plate heat exchanger is 700,000 kJ/h, which is approximately 167,000 kcal/h. 2. Flow rate of circulating water: The volume of circulating water V = Q/heat / (39 – 34) × 1 = 822029/4 = 164405 = 164.405 m³/h. The diameter of the circulating water pipe d = 0.197 meters (with a flow velocity of 1.5 m/s for the circulating water); thus, the pipe diameter is rounded to DN200, so DN200 is chosen.
IV. Calculation of the titanium cooler:
1. Heat balance: The temperature of the water entering the cooler is 40°C, while it exits at 12°C. The temperature of the chlorine water is 15°C. The heat carried into the cooler by the gaseous components is 113174 kilocalories. At 12°C, the saturated vapor pressure of water is 1.71 KPa; therefore, W_water = 28.949 kilograms (based on an annual production of 60,000 tons of 100% caustic soda). The solubility of chlorine gas at 15°C is 0.008495 kilograms per kilogram of water. Thus, the amount of chlorine gas lost is (132 – 28.949) × 0.008495 = 0.9218 kilograms. The amount of chlorine water produced is 132 – 28.949 + 0.9218 = 103.9728 kilograms. The heat carried away by the gaseous stream exiting the cooler is as follows: The specific heat of chlorine gas at 12°C is 8.214 kilocalories/Kmol·°C, the enthalpy of water vapor is 602.6 kilocalories/kilogram, and the specific heat of other gases is 6.9 kilocalories/Kmol·°C. The heat carried away by dry chlorine gas is QCl2 = 93.66 × 8.214 × 12 = 9233.85 kilocalories. The heat carried away by wet chlorine gas containing water is QH2O = 602.64 × 28.949 = 17444.26 kilocalories. The heat carried away by other gases is Q = 6.9 × 3.88 × 12 = 321.64 kilocalories. The heat removed by the chlorine water is Q = 103.9728 × 1 × 15 = 1559.59 kilocalories. In total, ∑Q_out = 9233 + 17444.26 + 321.64 + 1559.59 = 28558.24 kilocalories. The heat carried away by the chilled water is Q_in – Q_out = 113173.8 – 28558.24 = 84615.56 kilocalories.
2. Calculation of the heat exchange area of the cooler: The inlet temperature of the chilled water is 8°C, and the outlet temperature is 11°C. The inlet temperature of chlorine gas to the titanium cooler is 40°C, and the outlet temperature is 12°C. Δt = {(T1 – t2) – (T2 – t1)} / ln{(T1 – t2) / (T2 – t1)} = {(40 – 11) – (12 – 8)} / ln{(40 – 11) / (12 – 8)} = 12.62. Heat transfer rate Q = K × A × Δt. With K = 100 and A = Q/Δt × K = 84615 / (12.62 × 100) = 67.05 m².
3. Calculation of the amount of chilled water required: The volume of chilled water needed V = Q / (11 – 8) × 1 = 84615 / (11 – 8) = 28206.3 m³/h = 28.206 m³/h. The diameter of the chilled water pipe is 0.081 meters (with a flow velocity of 1.5 m/s for the chilled water); thus, the pipe diameter is rounded to DN100, so DN100 is chosen.
V. Calculation of the diameter of the acid pipes: In towers I, II, and III, the amount of sulfuric acid sprayed is 50 m³/h each. Therefore, the diameter d = 0.109 meters (with a flow velocity of 1.5 m/s for the sulfuric acid). The pipe diameter is rounded to DN125, so DN125 pipes are used. Ⅲ For the filler drying tower, the acid addition rate is 100 L/h, and a pipe with a diameter of DN25 is used. VI. Calculation of the sulfuric acid heat exchanger 1. The heat transfer capacity of the plate heat exchanger used in Tower I’s filler drying tower is 200,000 kJ/h (provided by Hangzhou Dongri Company), which is equivalent to approximately 47,619 kcal/h. Therefore, the amount of chilled water required for the plate heat exchanger in Tower I is as follows: the inlet temperature of the chilled water is 8°C, the outlet temperature is 11°C, and the flow rate of the chilled water is 1.5 meters per second. The specific heat capacity of water is 1 kcal/kg. ℃Using the formula W×CP×(T2-T1)＝Q, we obtain W＝Q/〈CP×(T2-T1) 〉. Thus, W＝47619/〈1×(11-8) 〉＝15873 kilograms/hour＝15.873 m3/hour. The diameter of the pipe for the chilled water is d＝0.061 meters; rounding this value gives DN65, so a DN65 pipe is used. Ⅰ. For the calculation of the area of the sulfuric acid plate heat exchanger in the packed drying tower, given that the inlet temperature of sulfuric acid is 16°C and the outlet temperature is 12°C, △t = { (T1 – t2) – (T2 – t1) } / ln{ (T1 – t2) / (T2 – t1) }. Thus, △t = { (16 – 11) – (12 – 8) } / ln{ (16 – 11) / (12 – 8) } = 4.48. The heat transfer rate Q is calculated as Q = K * A * △t; where K = 1500, and A = Q / (K * △t) = 47619 / (1500 * 4.48) = 7.086 m².
2. The heat transfer rates for the plate heat exchangers in packed drying towers II and III are both 79,000 kJ/h (provided by Hangzhou Dongri Company), which is approximately 18,810 kcal/h. The amount of chilled water required for each of these heat exchangers is W = 18,810 / <1 × (11 – 8)> = 6,270 kilograms/h, or 6.270 m³/h. The diameter of the chilled water pipes is d = 0.038 m; rounding this value up gives DN50, so DN50 pipes are used. II. Calculation of the area of the sulfuric acid plate heat exchanger in the filler drying tower: Given that △t = 4.48 and K = 1500, then A = Q/(K*△t) = 18810/(1500*4.48) = 2.799 m2. 3. The heat transfer rate required for the acid replenishment plate heat exchanger in the filler drying tower is 15,000 kJ/h (provided by Hangzhou Dongri Company), which is approximately 3,571 kcal/h. The amount of chilled water needed is W = 3571/〈1×(11–8)〉 = 1,190 kg/h = 1.19 m3/h. The diameter of the chilled water pipes is d = 0.017 m; rounding this value to the nearest standard size gives DN25, so DN25 pipes are used. Ⅲ Calculation of the area of the plate heat exchanger for acid addition in the filler drying tower: Given Δt = 4.48 and K = 1500, then A = Q/(K*Δt) = 3571/(1500*4.48) = 0.531 m2. Calculation of the diameter of the main pipe for chilled water: The total volume of chilled water is 28.3 m3/h from the titanium cooler, plus (15.9 + 7.1 + 6.3 + 1.2) m3/h from the sulfuric acid coolers, resulting in a total of 58.9 m3/h. With a flow rate of chilled water of 1.5 m/s, the pipe diameter d = 0.117 m; rounding this value gives DN125, so a DN125 pipe is used. VII. Calculation of the diameter of the chlorine pipe entering the chlorine washing tower. Under standard conditions (1 atm, 0°C), 1 mole of gas equals 22.4 m³ of gas. The number of moles of chlorine entering the tower per hour is as follows: the number of moles of dry chlorine is 93.75 mol, the number of moles of water vapor is 82.56 mol, and the number of moles of other gases is 3.88 mol. The volumetric flow rate of the gas at the inlet of the washing tower under standard conditions is V = (93.75 + 82.56 + 3.88) * 22.4 = 180.89 * 22.4 = 4036 m³/h. Given that the temperature of the chlorine before it reaches the washing tower is 80°C and the pressure is –0.5 KPa, the actual flow rate is V = 4036 * … = 5244 m³/h. The diameter d of the main chlorine pipe is calculated as follows: d = … = 0.393 (with a chlorine flow velocity of 12 m/s). Rounding up, the pipe diameter is set to DN400; thus, a DN400 pipe is used. VIII. Calculation of the diameter of the outlet pipe of the scrubber tower: The number of moles of gas exiting the scrubber tower is as follows – 93.66 moles of dry chlorine gas, 7.33 moles of water vapor, and 3.88 moles of other gases. The volumetric flow rate of these gases at standard conditions is given by V = (93.66 + 7.33 + 3.88) * 22.4 = 2349.09 m³. Given that the temperature of the chlorine gas at the outlet of the scrubber tower is 40°C and the pressure is –1.5 KPa, the actual flow rate is V = 2349.09 * … = 2731 m³. The diameter d of the main pipe for the chlorine gas at the outlet of the scrubber tower is calculated to be 0.311 meters (assuming a flow velocity of 10 m/s for the chlorine gas). Rounding this value up, the appropriate pipe diameter is DN350; hence, a DN350 pipe should be used.
This post was last edited by pzhhuagong on 2009-8-28 at 12:23. This book is great: “Chlorine Drying Technology and Acid Mist Removal Technology” http://bbs.hcbbs.com/viewthread.php?tid=59106, after page 21
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