In times of climate change and rising energy costs, new technologies are needed for sustainable and cost-effective production. In steam generation, for example, this includes the waste heat boiler, which utilizes and further processes previously generated energy.
The idea behind it is to use less energy overall by reducing resource consumption. This makes the waste heat boiler a solution that “kills two birds with one stone.” Because lower energy consumption also reduces operating costs. Thus, the waste heat boiler, as an ecological and economic optimization, is revolutionizing sustainable steam generation in industry.
We at JUMAG will show you how the waste heat boiler works, what advantages it offers, and which companies it is suitable for.
And this is how it works
The principle is simple: In numerous production processes that use steam, heat – and thus energy – is generated as a byproduct. This energy is wasted, and new energy must be generated for subsequent processes. This is where the waste heat boiler comes in. It specializes in harnessing the waste heat lost in energy-intensive machines. These can be combined heat and power plants or thermal energy recovery plants, for example. The waste heat boiler uses the waste heat from these machines to generate steam. How does this work? By considering the following points:
Utilizing temperature differences
The waste heat boiler is connected to the respective machine to capture the resulting waste heat. The temperature difference between the hot exhaust gases and the feed water is crucial. The greater the difference, the better the heat transfer.
Converting water to steam
Due to the temperature difference, water is heated in the waste heat boiler and converted into steam. The energy contained in the hot exhaust gases is thus converted into steam energy.
Consider the flue gas mass flow rate
The flue gas mass flow rate indicates the mass of flue gas produced per unit of time. This parameter influences the amount of energy available in the boiler.
Adjusting the steam pressure and temperature
The generated steam pressure and temperature depend on the intended use of the generated steam. Accordingly, the intended use determines the type of steam generator required.
Estimating steam output
Steam output is the amount of steam generated per hour. It depends on the amount of waste heat and the characteristics of the steam generator.
Selecting the steam generator size
Based on the expected steam output in kilowatts, a suitable steam generator is selected. This should not only cover current demand but also provide a reserve for future requirements and fluctuations in operation.
This is what the waste heat boiler does for industrial companies
The waste heat boiler is an attractive solution for many industrial companies that operate with steam, saving costs and protecting the climate.
The efficient use of energy through the reuse of heat improves the overall efficiency of the production process. Overall energy consumption is reduced, and less fuel is consumed while maintaining the same level of efficiency. This, in turn, lowers CO2 emissions and thus reduces the ecological footprint. At the same time, energy savings reduce operating costs and increase competitiveness.
This should be considered before installation
Save costs, maintain production, and protect the climate… – Sounds almost too good to be true! But only almost. There are several aspects that must be considered before purchasing a waste heat boiler to fully exploit its potential benefits.
1. Susceptibility to Contamination
The exhaust gases used may bring with them a lot of dirt, which can lead to deposits. These deposits impair the efficiency of the waste heat boiler. Therefore, regular cleaning is just as important as regular maintenance to ensure the longevity of the machine.
2. Installation Space Requirements
Installing a waste heat boiler requires a lot of space. Therefore, you should ensure that a sufficiently large maintenance room is available before purchasing.
3. Initial Investment Costs
Many companies face a small hurdle when it comes to using a waste heat boiler. This is because the investment costs for this solution are there. Even if the waste heat boiler leads to significant cost savings over its lifetime, companies should consider how they can cover the initial costs.
4. Dependence on operating conditions
The actual yield from the waste heat boiler also depends on operating parameters such as the exhaust gas temperature profile or machine operation. These affect the performance of the waste heat boiler. Therefore, the operating conditions may need to be adjusted.
This shows that a clear cost-benefit analysis should be conducted before purchasing. Because the investment is not worthwhile for every company.
The use of the waste heat boiler in numbers
Using three examples, we will demonstrate the application areas of waste heat boilers and their respective results:
Application: Baseload steam supply and grain drying
In an industrial context, an efficient waste heat recovery system is used to ensure a constant supply of steam for grain drying.
An integrated combined heat and power (CHP) plant has a total output of approximately 1 megawatt (MW). Approximately 400 kilowatts (kW) of this total output is generated as electrical energy. By generating heat from the combined heat and power plant, a considerable amount of steam can be produced simultaneously – approximately 330 kilograms per hour – at a pressure of 8 bar (gauge pressure).
The results in numbers: CHP plant / Output: Approximately 1 MW total, 400 kW electrical / approximately 330 kg/h at 8 bar (gauge pressure).
Application: Base load steam supply and heating of cooking kettles
Here, the combined heat and power plant (CHP) has a total output of approximately 285 kilowatts (kW), of which 100 kW is generated electrically. Thanks to the utilized waste heat, approximately 65 kilograms of steam are generated per hour at a pressure of 6 bar (overpressure).
The result in numbers: CHP / Output: Approx. 285 kW total, 100 kW electrically / approximately 65 kg/h at 6 bar (overpressure).
Application: Preheating feedwater for 2 x 6-ton Loos water-space boilers
Our final example concerns the application of preheating feedwater in the insulation board production for two 6-ton Loos water-space boilers (WRK). In this example, the combined heat and power plant (CHP) has a total output of approximately 900 kilowatts (kW), of which 360 kW is generated electrically. By reusing the waste heat, a whopping 290 kilograms of steam are generated per hour at a pressure of 6 bar (gauge pressure).
The results in figures: CHP plant / Yield: Approx. 900 kW total, 360 kW electrical / Approx. 290 kg/h at 6 bar (gauge pressure).
The examples demonstrate the efficient conversion of waste heat into steam by the waste heat boiler.
Save energy with waste heat boilers
The examples demonstrate impressive results through the individual implementation and adaptation of the waste heat boiler into industrial processes. The waste heat boiler holds the promise of an effective combination of ecological and economic benefits.
However, it also shows that the integration of the waste heat boiler does not work equally well in every company. All operational requirements must be considered when deciding on a waste heat boiler to ensure that the full potential of this sustainable technology can be realized. Please contact us for more information about the waste heat boiler or to receive a comprehensive cost estimate as part of our services.
