In the paint shop, it is not the average consumption of the jets that determines the boiler, but the peak steam drawn in the heating ramp: a 500 kg HT jet heats from 25 °C to 100 °C and draws about 2,990 kg/h of steam, while the average of an 8-hour batch is only 365 kg/h. On the other hand, not all jets heat at the same time; in a 24-jet paint shop, the number of jets heating at the same time does not statistically exceed 7–8. The Çiftel Kazan wizard calculates your jet, coil, washing, drying and stenter machines one by one with physical models, applies the simultaneity by binomial method and outputs the steam boiler separately from the thermal oil boiler required for the stenter.
Which machine draws how much steam?
| Machine | Typical capacity | Vapor / heat | Pressure/temperature |
|---|---|---|---|
| HT jet, cotton reagent | 500 kg/batch, liquor 1:8, 8 h batch | peak 2,990 kg/h · average 365 kg/h · batch 2,920 kg (5.84 kg/kg) | 7 bar g |
| HT jet, polyester 130 °C | 500 kg/lot, liquor 1:6, batch 3.5 h | peak 2,342 kg/h · average 457 kg/h · batch 1,600 kg (3.2 kg/kg) | 7 bar g |
| Coil yarn dye, polyester | 1,000 kg/batch | peak 5,376 kg/h · batch 4,082 kg | 7 bar g |
| Skein paint | 300 kg, liquor 1:15, 98 °C | peak 1,209 kg/h · 736 kg per bath | 5 bar g |
| Continuous washing (weaving) | 1.296 kg/h, 8 L/kg, 85 °C | 1,231 kg/h (0.95 kg/kg) | 5 bar g |
| Open width washing (knitted) | 1,000 kg/h, 6 L/kg, 80 °C | 581 kg/h | 5 bar g |
| Mercerized | 1,200 kg/h | 660 kg/h | 5 bar g |
| Roller dryer | 1.296 kg/h, moisture 60% → 7% | 1,022 kg/h | 3 bar g |
| Sanforizing / compactor | 1,152 / 600 kg/h | 514 / 175 kg/h | 3 bar g |
| Fabric tumbler | 150 kg, 40 min cycle | peak 448 kg/h · average 309 kg/h | 7 bar g |
| Sizing machine | 600 kg/h yarn | 770 kg/h (1.28 kg/kg) | 3 bar g |
| Stenter, drying | 500 kg/h, 8 chambers, humidity 70% → 7% | 394 kW regime · 492 kW heating | thermal oil 260°C |
| Ram, heat-fixation | 8 cabin × 100 kW | 800 kW regime · With 1,000 kW heating | thermal oil 260°C |
| Kalandır | 1,000 kg/h, roller 180 °C | 99 kW regime · With 149 kW heating | thermal oil 230 °C |
Example: medium dyehouse processing 20 t per day
The “Medium dyeing-finishing” template in the wizard: a plant that works in three shifts, dyeing and finishing 20 t of knitted fabric per day. The stenters are heated with thermal oil.
| Machine | Quantity | Single machine peak | Simultaneous load |
|---|---|---|---|
| HT jet, 290 kg/batch, cotton reagent | 24 | 1.734 kg/h | 12.888 kg/h (× 0.31) |
| Open width washing, 1,000 kg/h | 1 | 581 kg/h | 581 kg/h |
| Fabric tumbler, 150 kg | 2 | 448 kg/h | 716 kg/h (× 0.8) |
| Compactor, 600 kg/h | 2 | 175 kg/h | 350 kg/h |
| Ram, 8 cabins, 500 kg/h | 2 | 492 kW | 984 kW (thermal oil) |
- Simultaneous steam requirement of the machines: 14,536 kg/h (even though the flat sum of the jet peaks is 41,619 kg/h).
- Line losses (5%) +727 kg/h, deaeration steam +1,229 kg/h, growth share (10%) +1,649 kg/h → 18,141 kg/h.
- Recommended steam boiler: 19 t/h, working pressure ≥ 8.5 bar g (10 bar design class), feed water 105 °C (with deaeration), condensate return 70%.
- Boiler thermal power 11,813 kW ≈ 10,157,000 kcal/h; average steam 6,961 kg/h. Natural gas ≈ 1,338 Sm³/h at full load, 555 Sm³/h ≈ average.
- Thermal oil: two rams 984 kW → 977,604 kcal/h thermal oil boiler with line loss and growth margin → 1,000,000 kcal/h, 260 °C going.
- Sector supply: 8,354 kg of steam/t product (8.4 kg/kg); in the range of 4–14 kg/kg, based on the measurement of 44 plants in Turkey.
- Other templates: 6-jet small knitted dyehouse (5 t/day) → 6 t/h steam + 500,000 kcal/h thermal oil; 50 jet and 4 bobbin integrated plant (60 t/day) → 44 t/h steam + 3,750,000 kcal/h thermal oil.
Why does jet simultaneity shrink boiler?
A jet draws steam at full throttle only on the heating ramp: 12% of the ≈ of the 8-hour batch in the cotton reagent program, 22% of the ≈ in polyester. Since the batches are started by shifting, it is practically not possible to heat 24 jets at the same time. The wizard calculates this by binomial method : the probability that each jet is heating at any given moment is taken φ (16% in the mixed dyehouse) and the maximum value of the number of jets heating at the same time is found with a probability of 97.5%. In 24 jets, this value is ≈ 7.4 jets, i.e. the simultaneity is 0.31. As the number of jets increases, the coefficient decreases: 1 jet 1.00 · 4 jets 0.53 · 6 jets 0.46 · 10 jets 0.39 · 24 jets 0.31 · 60 jets 0.25. In the example above, if concurrency was not applied, a 54 t/h boiler would be recommended for the same plant; with the binomial method, 19 t/h is sufficient. The simultaneous load never goes below the average consumption; if the batches start together at the beginning of the shift, increase φ. If the boiler remains small, the heating rate of the jets drops below 5 °C/min, and the batches become longer.
Boiler type and pressure in the paint shop
Jets and winding machines require 7 bar g of dry saturated steam; the boiler therefore operates at at least 8.5 bar g and is selected in the 10 bar class. The washing (5 bar g) and drying cylinders (3 bar g) are supplied by pressure reducing stations. Most of the condensate rotates; the direct steam of pad-steam, fixation and sanforizing spray does not rotate.
Why does the stenter run on thermal oil? A heat-setting requires 180–210 °C of hot air. The temperature of saturated steam depends on its pressure: 184 °C at 10 bar g, and the steam coil can only heat the air to 160–170 °C. For 200 °C of air, ≈ 230 °C of heater surface, i.e. ≈ 27 bar g of steam is required; at this pressure, the boiler, pipeline and condensate system are not economical. Thermal oil, on the other hand, reaches 250–280 °C without pressure and heats the chambers quickly and evenly. Therefore, the stenters work with thermal oil or directly with the gas burner; it is not a direct gas stenter boiler load. A stenter that dries alone can also work with steam, but a 500 kg/h stenter draws 886 kg/h of steam at 10 bar g and pushes the boiler to 12 bar class; 500,000 kcal/h thermal oil boiler is sufficient for the same stenter. The remaining 180 °C roller requires 230 °C thermal oil.
Product selection: Package type and hybrid type steam boiler are suitable for steam needs up to 6 t/h, and header type water tube steam boiler above 6 t/h are suitable. An economizer that gives flue gas heat to feed water at 2 t/h and above is recommended.
How to do the calculation?
In a 500 kg jet, the ≈ C is 19,430 kJ/K; with 5 °C/min heating and 5% loss, the peak ≈ at 7 bar g is 2,990 kg/h. With the jet load binomial coefficient, continuous machines are collected with full load; then 5% line loss, deaerator steam (above 1.5 t/h) and 10% growth margin are added from the mass and energy balance. The stenters and the remainder are calculated as a separate thermal oil circuit.
Use the wizard at the top of the page to calculate with your own list of machines; Boiler Capacity Calculator for all industries.
The results of the wizard are predictions to give a preliminary idea; boiler selection should be finalized by on-site exploration and engineering calculation. Contact us for free pre-engineering support.