Typically, boiler models are differentiated by what fuel is used to power them. It's important to pay attention to the type of fuel your boiler needs, as it often has a significant impact on your operating costs. It can also have an impact on your environmental impact, so familiarity with all the various types of boiler fuels is essential.

Fuel cost is the most important cost in boiler operation cost, and boilers operation cost with different fuels is also different. Especially at the beginning of boiler selection, it is the most important to choose the most suitable type of boiler for fuel. So, what fuel has the lowest operating cost for a boiler?

First of all, what is boiler fuel? The so-called fuel is a substance that releases a lot of heat energy when it is burned and can be effectively used. The fuel used in boiler combustion can be divided into solid fuel, liquid fuel, gas fuel and other four types according to their different physical states.

Boiler Fuel Classification

1. Solid fuel  

Coal, biomass briquette, wood, other biomass fuels.

2. Liquid fuel    

Gasoline, diesel, heavy oil, LSHS, LDO, etc.,

3. Gas fuel   

Natural gas, liquefied petroleum gas (LPG) blast furnace gas, city gas, etc.,

4. Agricultural waste   

Husks, bags, corn cob, peanut shells, etc.

The calorific values of common fuels are as follows:

Common Boiler Fuel Costs

 The calorific value of boilers with different fuels

The calorific value of different fuels is different, and the thermal efficiency of different boilers is also different. We can compare and calculate the calorific value generated by boilers with different fuels based on five common boiler fuels:

(The thermal efficiency of the following boilers is an average value, and the data is for reference only)

(1) The thermal efficiency of the natural gas boiler is 85%, the calorific value of the natural gas is 8600 kcal/m3, and the actual calorific value of the natural gas is 8600 kcal/m3×85%=7310 kcal/m3.

(2) The thermal efficiency of the coal-fired boiler is 70%, the calorific value of coal is 5000 kcal/kg, and the actual calorific value of coal is 5000 kcal/kg×70%=3500 kcal/kg.

(3) The thermal efficiency of the heavy oil-fired boiler is 76%, the calorific value of heavy oil is 9700 kcal/kg, and the actual calorific value of heavy oil is 9700 kcal/kg×76%=7370 kcal/kg.

(4) The thermal efficiency of the light diesel boiler is 85%, the calorific value of light diesel is 10200 kcal/kg, and the actual calorific value of light diesel is 10200 kcal/kg×85%=8670 kcal/kg.

(5) The thermal efficiency of the electric heating boiler is 96%, the calorific value of the electric heating boiler is 860 kcal/kWh, and the actual calorific value of electricity is 860 kcal/kWh×96%=825.6 kcal/kWh.

The cost comparison under the same situation is as follows: (The following fuel prices are collected from the Internet, for reference only)

What is the cheapest fuel for a boiler?

The market price of natural  fuel is 4.2 yuan/m³,1-ton boiler full load natural gas consumption is 82m³/h, 82m³/h×4.2 yuan/m³=344 yuan, natural gas boiler is calculated according to 8 hours a day: 344 yuan/h×8 h=2752 yuan .

The market price of coal fuel is 950 yuan/ton, and the full load operation of a 1-ton boiler is 170 kg/h × 950 yuan/ton = 160 yuan/h, and 160 yuan/h × 8 h = 1280 yuan/day based on 8 h of operation every day.

The market price of heavy oil fuel is 4.8 yuan/kg, 82 kg/h x 4.8 yuan/kg = 394 yuan/h for full load operation of 1 ton boiler, 394 yuan/h x 8 h = 3152 yuan/day for 8 h of operation every day.

The market price of light diesel fuel is 8.1 yuan/kg, 69 kg/hour x 8.1 yuan/kg = 559 yuan/hour for full load operation of 1 ton boiler, 559 yuan/hour x 8 h per day = 4472 yuan/day .

The market price per kWh of industrial electricity is 1.1 yuan/kWh, and the full-load operation of a 1-ton boiler is 727 kWh/h× 1.1 yuan/kWh = 800 yuan/hour, and 800 yuan/h × 8 h = 6400 Yuan/day.

According to the above comprehensive comparison, coal-fired boilers have the lowest cost and the cheapest.

Since the cost of coal-fired boilers is the lowest, should you choose coal-fired boilers as your ideal boiler? The answer is NO.

Three Factors to Consider Before Deciding Which Boiler Fuel

It's not just cost that needs to be considered before deciding on the type of boiler fuel. Taken together, three factors need to be considered.

The first factor is boiler fuel cost. Is the cost of one fuel type significantly different from the cost of another? Is it reasonable to use lower quality fuel or less stable fuel?

The second factor is ease of use and security. How do you expect the boiler will need to be maintained over its life cycle?

The third consideration is the life of the boiler with a given fuel type. How long will a boiler on one fuel last compared to a boiler on a different type of fuel? In addition, boiler emissions are also a factor that cannot be ignored. 

1. Boiler Fuel Cost

The cost of boiler fuel depends on many variables, with location having the most impact. In places like Bangladesh, gas boilers are usually the preferred type of boiler fuel, reference data is shown in the chart below.

Another example, taking China as an example, like Northeast China, oil is usually the preferred type of boiler fuel because it is cheaper than natural gas, propane and coal. However, in other parts of China, this is not always the case. Natural gas and propane are cheaper in the deserts of the Southwest. Coal is generally less expensive on the East Coast and southern states. 

2.Boiler Ease of Use and Safety 

The type of fuel you choose will largely determine the ease of use of your boiler. What's more, the type of fuel plays a vital role in the safety precautions that must be taken when using and maintaining the boiler. Propane and natural gas are extremely volatile. 

This means that if there is a leak in the pipes or boiler, you must leave the site and have it repaired by an expert. 

Fuel oil and coal are extremely stable fuels, much more stable than gaseous fuels and gasoline. In the event of a fuel leak, there's no real danger even to someone who doesn't have the expertise to fix the problem.

The stability of the fuel means you can make simple repairs easier, saving you time and money. 

Coal is the most stable of all fossil fuels. The chance of explosions associated with coal is virtually nil, which is an inherent hazard with gaseous fuels. 

3. Boiler Life For a Given Fuel Type

1. Among 1T, 2T, and 3T boilers, the initial fixed investment of gas boilers and oil boilers is the least;

2. In the service life of the boiler, the gas boiler is generally 20 years, which is the longest among all types of boilers;

Therefore, in terms of investment in fixed assets of various types of boilers, investing in gas boilers is undoubtedly a better choice.

Precautions For Choosing Boiler Fuel

Fuel Availability

Fuel should be readily and widely available near the plant site. Generally, areas close to coal belt users prefer coal as a fuel. Those places where agricultural waste can be obtained from plants at a lower price, use the same method, for example rice mills will use rice husks as fuel, so they choose to use rice husk-fired boilers. Use these in places where oil or gas is cheap, such as OPEC countries. Oil and LPG are more expensive in India. If natural gas is available, you can consider it an option.

Alternative Fuels

You should choose a boiler, it would be an added advantage if you could use multiple fuels (of the same family).

Fuel cost is the most important aspect of choosing boiler fuel. In order to achieve the operating efficiency and economic benefits of the unit.

Pollution Control Regulations

When choosing a fuel type, you should consider the pollution control regulations of your region/state/country. Natural gas and oil should be chosen if there are restrictions on emissions within the city limits/in some SEZs.

Note: In some sectors/regions, pollution regulations prohibit the use of solid fuels such as coal or agricultural waste. Although expensive, oil or natural gas is used as fuel in this case.

Conclusion:

As a major part of boiler cost, fuel cost should be carefully selected at the beginning of boiler selection. Initial fixed investment, depreciation rate, annual operating expenses and whether the government supports it should be carefully considered.

Before EPCB customizes a boiler for you, it will conduct research on your local fuel market, and provide a full range of services such as site survey, boiler design, on-site installation, post-commissioning, and maintenance.

EPCB, your personal boiler system expert!

Further Reading:

Boiler Burner Selection Guide | How to Choose a Suitable Burner?

Boiler Selection Guide|How to choose a steam boiler and steam generator?

How to choose a boiler with high temperature heating?