The calculation of plant gas consumption needs to take into account equipment operating requirements, system losses and future expansion planning, as follows:
1. Basic data of statistical equipment
- gas consumption of single equipment: Refer to the equipment nameplate or technical manual and record the rated gas consumption of each gas equipment (unit: cubic meters/minute or liters/second).
- Frequency of use of equipment: Record the daily operation time of the equipment (e. g. 8 hours/day) and the working cycle (e. g. continuous operation or intermittent operation).
2. Calculate the daily air consumption of a single equipment.
- Formula daily air consumption of single equipment = rated air consumption × daily operation time.
- Example: If the rated gas consumption of a certain equipment is 0.5 cubic meters/minute and it runs for 8 hours per day, its daily gas consumption is 0.5 × 8 × 60=240 cubic meters.
3. Summarize the total gas consumption of equipment in the whole plant
- add the daily air consumption of all equipment to obtain the total daily air consumption of the plant.
- Formula: Total daily air consumption of the plant = & Sigma;(daily air consumption of a single unit).
4. Consider system losses and safety margins
- pipeline leakage: For leakage of compressed air system pipelines due to loose joints, pipeline damage, etc., a margin of 10%-30% of the total air consumption is usually reserved.
- Equipment aging: The decline in equipment performance may lead to an increase in gas consumption. It is recommended to reserve a margin of 5%-10%.
- Future Expansion: If the factory plans to add new equipment or expand production, additional gas shall be reserved according to the expected increase (e. g. 20%).
5. Determine the basis for air compressor selection
- compressor displacement: It needs to be greater than the total gas consumption of the factory (including system loss and safety margin).
- Pressure demand: Select the compressor according to the maximum working pressure required by the equipment (e. g. 7bar) and ensure that the pipeline pressure loss (usually 0.5-1bar) is taken into account.
Example calculation
suppose a factory has 3 devices:
- equipment A:0.5m & sup3;/min, running 8 hours/day
- equipment B:0.3m & sup3;/min, running 6 hours/day
- equipment C:0.2m & sup3;/min, running 24 hours/day
daily air consumption of a single unit:
- a:0.5 × 8 × 60=240m³
- B :0.3 × 6 × 60=108m³
- c:0.2 × 24 × 60=288m³
total daily gas consumption of the plant: 240+108+288=636m & sup3;
including loss and margin: 636 × 1.3 (system loss) × 1.1 (safety margin) & asynmp; 912m & sup3;
conclusion: The factory needs to select an air compressor with a displacement of at least 912m & sup3;/day, and ensure that its pressure output meets the equipment requirements. By regularly detecting pipeline leaks and optimizing equipment operating time, gas efficiency can be further improved.
