A dual-fired steam boiler is designed to be able to burn both oil and gas as fuel, providing flexibility in fuel choice based on availability and cost. The capacity of the boiler is often measured in terms of steam production per hour. In your case, you're referring to a 2-ton steam boiler.

Here are a few points to consider:

1. Capacity: A 2-ton steam boiler typically refers to the amount of steam produced by the boiler in one hour. This can vary depending on the pressure and temperature settings.

2. Dual-Fired: The boiler can operate on both oil and gas as fuel. This allows for fuel flexibility and adaptation to changing fuel prices and availability.

3. Efficiency: The efficiency of the boiler will impact the amount of fuel needed to generate the desired amount of steam. Higher efficiency boilers use fuel more effectively.

4. Emissions: The combustion of oil and gas can result in emissions. Modern dual-fired boilers often incorporate technologies to minimize emissions and meet environmental regulations.

5. Maintenance: Regular maintenance is essential for the safe and efficient operation of the boiler. Both the oil and gas burners need proper maintenance to ensure reliable performance.

6. Safety: Dual-fired boilers need to have safety features and controls to ensure safe operation regardless of the fuel being used.

7. Local Regulations: Ensure that the boiler complies with local safety and environmental regulations in Iran.

When it comes to obtaining accurate and up-to-date information about a specific 2-ton dual-fired steam boiler in Iran, I recommend reaching out to local boiler manufacturers, suppliers, or distributors. They can provide you with quotations and specifications tailored to your needs and local conditions.

Keep in mind that boiler prices can vary based on factors such as brand, features, efficiency, and regional market conditions. Consulting with experts in the field and obtaining multiple quotes will help you make an informed decision.