I have a gas boiler, I want to know how much steam is used to process 1 kg of linen and how much it costs

 

Nice — let’s do this step-by-step so you get a practical answer you can use on the shop floor.

These numbers are examples — I’ll show how they were calculated so you can plug in your real values.

What I assumed (so you can change them if needed)

1.    Steam properties — saturated steam enthalpy of vaporisation ≈ 2,046.5 kJ/kg (value used for steam at around ~7 bar gauge). Engineering ToolBox

2.    Boiler fuel-to-steam (fuel) efficiency = 85% (typical modern industrial gas boiler range ~80–88%). powerhouse.com

3.    Gas cost — I used India benchmark gas price INR 1,057 per MMBtu (Gas Index of India, April 2025). Replace this with your actual fuel price for exact cost. Energetica India

(If you operate at a different steam pressure use the enthalpy corresponding to that pressure — enthalpy drops slightly with higher pressure. Engineering tables show the exact numbers.) 

Notes, caveats & how to get a precise number for your plant

•      What “1 kg linen” means — actual steam needed depends on fabric, initial moisture content, and the operation (ironing only vs drying vs steam chest pressing). Typical ironing/pressing uses much less steam than dryer/evaporative processes.

•      Steam pressure matters — at higher pressures latent heat per kg changes slightly (use steam tables for precise h_fg at your operating pressure). thermopedia.com

•      Boiler efficiency can vary (scale, blowdown, stacking losses). Use your boiler’s actual fuel-to-steam efficiency for best accuracy. powerhouse.com

•      Fuel type matters — I used the India natural-gas benchmark. If you use LPG or PNG or furnace oil, replace the fuel price and calorific conversions accordingly. (I can convert if you give me your fuel type and price.) World Nuclear Association

Practical ways to measure real steam use:

•      Fit a steam meter (vortex/differential) on the branch feeding the press/finishing line.

•      Measure condensate return mass/temperature and calculate steam input from mass and enthalpy balance.

•      Use your boiler gas meter energy reading and proportionate loading/time to apportion fuel to specific processes.

 

I would like to emphasize that this note is shared purely for knowledge-sharing and educational purposes.

 

Few points to consider in Washing machine capacity.

As rightly emphasized, washing machines should be loaded based on volume rather than only weight. This is especially relevant since we process a wide range of textile materials—100% cotton, polyester–cotton blends (e.g., 66% polyester + 33% cotton), 100% polyester, wool, silk, heavy textiles, and even industrial items.

·         To begin with, it is important to understand how washing machine capacity is rated. No manufacturer can set their own standards independently; all must adhere to ISO standards. According to ISO Standard 3.1 (see attached reference), cotton is designated as the test load material.

·         

Further, ISO Standard 3.3 defines the ratio of cotton load to drum volume as 

1:10 kg of cotton per drum volume. Connecting these two points makes it clear that cotton is the benchmark textile for machine capacity testing.

KEY POINTS

When water interacts with different fibers, their physical properties change as follows:

·         100% Cotton: Shrinks the most in volume.

·         Polyester–Cotton (PC) blends: Shrink proportionally, depending on the cotton percentage.

·         100% Polyester: Shows negligible shrinkage.

 

We also know that effective textile cleaning is a combination of chemical action, heat, and mechanical movement. Since cotton compresses more, it requires less drum volume per kilogram, while polyester requires more drum volume per kilogram.

Conclusion:

The same drum volume corresponds to different loading capacities depending on the textile material.

 

Example:

·         A 100-liter drum may hold 10 kg of 100% cotton, but only about 7 kg of 100% polyester.

 

 Since cotton represents the maximum load with minimum volume, manufacturers logically use it as the reference point for capacity ratings. However, as industry professionals, we must understand the scientific and practical reasoning behind these standards.

 

 I would like to emphasize that this note is shared purely for knowledge-sharing and educational purposes.