Energy Savings in the Asphalt Manufacturing Industry

by: Ryan Worral, P.Eng.

Summary

Typical Hot Mix Asphalt (HMA) plants are equipped with hundreds of feet of uninsulated flexible metal “jumper” hoses. The primary function of the “jumper” hose is to transfer hot process oil in a primary jacketed pipe across a connection flange. Traditional insulating technologies that utilize mineral wool and hard aluminum cladding are not capable of servicing these hoses as they have a small diameter and a very tight bend radius. The result is that the “jumper” hoses are left uninsulated and they are a significant source of heat loss costing HMA plants thousands of dollars each year in energy inefficiencies.

Recent improvements in thermal insulation technology have finally enabled HMA plants to insulate the neglected “jumper” hoses and recover significant capital in energy savings.

The Technology

Recent advancements in insulation technology are utilizing closed cell silicone sponge rubber as a primary source of high temperature insulation protection. The advantage of this material is that it has a very low thermal conductivity making it an excellent insulator. In addition silicone sponge rubber is non fiberous unlike traditional mineral wool and it does not required a hard aluminum cladding to contain the insulation materials. The inherent flexibility of silicone sponge rubber in combination with the aforementioned properties, make it an excellent solution for insulating the tight bend radius “jumper” hoses.

Economic Benefits

Insulating 1 ½” OD flexible metal hoses with silicone sponge rubber sleeves (under typical operating conditions) enables HMA plants to recover up to $30 in heat losses for every foot of “jumper” hose in one seven (7) month operating season (assuming a winter shut down). This translates into fuel heating costs savings of approx. $6,000 per operating season (Assuming 200 ft of “jumper” hose. Costs are based on 2005 North America fuel costs).

In most applications the flexible insulation sleeve will pay for itself within the first four (4) months of installation.

Installation Benefits

In addition to the economic benefits, the new insulation sleeve technology is easily cut to length with an ordinary pair of scissors and is quickly installed in the field. In many cases the insulation sleeve may be equipped with a hook and loop closure to further simplify the installation on existing lines without line disconnection or interruption. The hook and loop closure also allows for easy access to process lines while performing maintenance procedures or trouble-shooting system components.

Conclusion

Introducing the HMA industry to silicone rubber sponge insulation technologies will help demonstrate unrealized energy savings while creating a safer workplace environment.