What is the calculation method for steam consumption rate of steam turbines?
2 Answers
Steam consumption rate equals the main steam flow multiplied by 1000 and then divided by the power generation, with a rated steam consumption rate of 3.025kg/kW.h. The main steam flow is an accumulated figure for a day or a shift. The instantaneous main steam flow seen on the DAS screen is not measured directly but calculated using the formula: main steam flow G equals (PⅠ2-P high exhaust2) to the power of 0.5 multiplied by 81.9 multiplied by 540 and then divided by the superheater outlet temperature. PⅠ is the regulator pressure. Function: Steam turbines, also known as steam turbine engines, are rotary steam power devices. High-temperature and high-pressure steam passes through fixed nozzles to become accelerated airflow, which is then ejected onto blades, causing the rotor equipped with blade rows to rotate and perform external work. Steam turbines are the main equipment in modern thermal power plants and are also used in metallurgical industries, chemical industries, and ship power plants. Working Principle: Steam turbines are external combustion rotary machines capable of converting steam thermal energy into mechanical function. Steam from the boiler enters the turbine and passes through a series of annularly configured nozzles and moving blades, converting the thermal energy of the steam into the mechanical energy of the turbine rotor's rotation. The steam in the turbine undergoes energy conversion in different ways, forming turbines with different working principles.
Calculating the steam consumption rate of a steam turbine is not complicated. I learned it through practical operation. The basic formula is steam consumption divided by output power. Steam consumption is measured in kilograms per hour (kg/h), and power is expressed in kilowatts (kW) or megawatts (MW). The resulting steam consumption rate is measured in kg/kWh. For example, if a steam turbine consumes 10,000 kg of steam per hour and outputs 2,500 kW of power, the steam consumption rate would be 4 kg/kWh. Factors affecting this rate include steam inlet temperature and pressure: higher temperatures and pressures typically result in lower steam consumption rates, indicating higher efficiency. Load fluctuations also impact the results—less steam is consumed at high loads, while more is wasted at low loads. Regular monitoring of the steam consumption rate helps optimize operating costs and reduce fuel consumption. A sudden increase in this value may indicate seal leaks or wear, requiring prompt maintenance to prevent equipment damage. This principle is similar to monitoring a car engine's fuel consumption, both based on the input-output ratio to assess overall performance. Maintaining accurate records is crucial. In practical applications, engineers use on-site instruments to read data and validate accuracy with thermodynamic models. Long-term tracking can enhance equipment lifespan and economic efficiency.
