Energy Savings and Improved Uniformity with the Airtorch® – Deep Decarbonization
Energy: When one includes the social cost of CO2 production, the price of one KWh of electric or combustion energy starts converging. For example, if the social cost of making CO2 is $50/ton, then the price of 1 KWh of electric or similar energy from the combustion of natural gas is not too different. If the efficiency of Airtorch devices is even 25% better than combustion heat exchangers, then the operational cost of the electric Airtorch is lower than the combustion heat exchanger devices. For example, a 14.2 MW combustion gas heater could be replaced with a 12MW electric Airtorch. A savings of $48,000 per day (assuming 1 KWh ~10 US cents).
There are other cost benefits. The pressure drops for electric Airtorch devices are lower than traditional heat exchanger devices. For a 2000 SCFM flow, saving ~5 psi in pressure drop is equivalent to about 30 KW in power savings. This is almost a savings of $25,000 per year, assuming a price of 10US¢ per KWhr.
Did you know that converting from a 16MW combustion heater to Electric Airtorch can save over 30% energy and several millions of dollars in climate costs? MHI Airtorch® models are designed with thermal energy loss reduction and pressure energy loss reduction features. MHI Airtorch® models offer a high-temperature input, even to 500°C, which is particularly useful for Duct-Heatare used in ovens to replace natural gas heating.
For the best energy saving, gs compare the following:
The efficiency of thermal transfer. What is the actual efficiency to theoretical efficiency? Depending on the model, the MHI Airtorch® systems offer more significant than 95% efficiency.
Pressure drop. Some large MHI models allow a pressure drop at 1000C of as low as 0.1 psi. Is it the lowest for the Airtorch®?
Control systems. Does your control have an excellent turn-down ratio and intelligent cascade electronics? MHI uses the best SCRs and electronics that are industry standards.
Materials and Design. What is the best temperature rating of the Airtorch?®. Depending on the model, MHI Airtorch® systems offer 1200°C exit temperatures. A higher temperature-rated Airtorch® will perform better even at a lower temperature.
If lesser energy can be used for the same objective, it will substantially reduce CO2 emissions. Modern light generators (bulbs) produce the same visible light intensity with much less energy.
Improved practices. There is no need to pressurize compressors and bleed them every day. Pressurization leads to substantial energy demand. If using high-volume airflows, ensure that the pressure drop is the least.
Always prefer electric devices over combustion devices. Opt for modern electric machines; they probably use less energy for the same objective than a machine with a combustion source. For example, we have shown that a 16MW gas heater can be replaced by an 11MW electric Airtorch® for the same heating objective. Or use an electric instant steam generator instead of a conventional boiler. Or implement methods to conserve the quality of energy.
Did you know that saving 5MW Powerower in a device for the same objective saves well over US$3.5 Million for the year in the cost of electric energy? More resources
Upgrade equipment. Replace old furnaces and devices with modern ones that offer the most modern emissivity heaters, crisp controls, safe insulation, and ergonomics. Use higher temperatures for processing for the same objective to glean profits from higher productivity.
Please use5-step step process for selection. First, choose the maximum rated exit temperature of the Airtorch®. If below900°C, please select TA models, e.g., VTA and Mls. If above 925°C, please choose the MVTA or DPF model – please get in touch with MHI.
Sometimes, the lowest power users work through several cycles in a recuperator mode. The SH models can accept inlet gas temperatures up to 800°C. Please get in touch with MHI for details.
The Airtorch® convective system uses a particular class of elements to heat the ambient air and direct that heated air towards a surface or into a chamber. Depending on the model, the Airtorch® system can achieve temperatures ranging from room temperature to 1100-1200°C (~2200°F) with infinitely variable volume flow rates and no harmful emissions, providing a beneficial new method of heating with modern controls.
MHI Airtorch® applications are in drying electrical varnish, weld preheating, die heating, plastic softening before forming, drying motor parts, removing moisture, expansion fitting, combustion, simulation preheating and heating molds, curing, prosthetics, heat shrinking, compression molding, flock setting, curing catalysts drying slurries, freeze-drying, improving ink print finish, finishing mirror drying, latex, heating adhesives, and general heating of chambers as shown below. Add to chambers for powder and liquid finishing. Add to continuous furnaces for wood conditioning, metal finishing, and forming. A small but finite temperature drop is experienced when directing Airtorch® flow with insulated piping because of the high velocity.
For impingement types of applications, the DPFs offer very superior value.
A good rule of thumb for augmenting uniformity in an existing furnace with an Airtorch® add-on is choosing an Airtorch® power with at least 30% of the original. This may not be enough if a temperature increase is also sought.
When planning to extend the Airtorch® exit piping, please note that well-insulated pipes will drop the temperature very little as the exit velocity is m/s. A helpful but rough rule of thumb may be about 50°C-100°C/m drop for good internal pipe insulation. Good pipe insulation is specific to the insulation and whether the pipe is internally or externally insulated. The MHI industry standard is about a 1-2″ thick insulation. Please get in touch with MHI when required.
The use of Airtorch® products may be classified into three major categories schematically drawn below.
With its variable volume flow rate and power adjustability, the Airtorch™ can be set up to perform at any condition of flow temperature under the curve. Such features offer the user maximum flexibility when applying the Airtorch™ technology to heating applications.Easy to use selection and design page.
Example of Use to Augment an Existing Furnace Installations for Improved Power and Uniformity.
An example of a 4kW Airtorch® augmentation application is schematically shown below. In this application, many complex-shaped rods are to be heated uniformly. The heat-treater reported that the rods were not uniformly heated in his existing radiant heat furnace. MHI proposed an add-on to his existing furnace with a system of Airtorch products, significantly impacting the uniformity – reducing the total energy consumed. More Green Installation and more Profits to the user. Improve oven performances and eliminate harmful emissions.
A uniform surface heating retrofit example and continuous oven examples are illustrated below.
As a rule of thumb, an Airtorch power of ~0.3 the furnace power is employed when designing for better uniformity.
MHI Airtorch® Supplemental Heating Proposal
Scope: Supplement existing electrodes by applying Airtorch convective heating to increase performance and life
Solution: By supplementing the existing electrodes with the Airtorch® and blankets, the watt density is increased on the mold, thus reducing the workload of the existing electrodes, which should improve performance and life. Other results include an increase in uniformity across the mold surface. Call MHI for more information.
1 Heating: Create a convective cavity around the assembly using two 4kW Airtorch® units. Fixture Airtorch units behind mold and electrodes at angles to create air movement. This should improve the overall heating of the mold.
2 Insulation: The assembly is surrounded by refractory blankets (five sides) to retain as much heat as possible.