Single Screw Extrusion

Hi Bill,

The problem is simple math. When you reduce the steam valves by ½, the flow volume is reduced by a factor of 4. You will maintain the pressure/temperature (sensible heat) but the steam flow will be reduced by the factor of 4. This reduces the latent heat transfer to the product by the same factor.

A couple of questions:

Why was the valve sizes changed? Was it done to reduce energy use? What is the condensate outlet pressure?

We solved a similar problem in a waste water treatment plant at a major pulp and paper facility in 2006. They were furnishing 40 psi of steam to a sludge screw press and then vented the condensate (and steam) to the atmosphere. This was grossly inefficient and counterproductive because it allowed the steam to blow straight through the unit without giving up its latent heat.

To fix the problem, we installed an Electronic Condensate Controller. My company manufactures this product. This device slows the steam flow through steam users and forces the steam to give up a much greater proportion of its latent heat (thus making the process more efficient). By installing the ECC, we controlled the release of latent heat to the sludge product. This resulted in a 25% reduction in energy use. It also enabled the plant to burn the sludge in a wood fired boiler on the site rather than haul it away to a hazardous waste land fill.

The ECC was installed in August 2006 and has performed flawlessly.

For more information on the condensate controller visit our web site at khengsys.com.

Thanks,

Hie Sheppard

The steam valves were reduced in size because it was believed that the originals were oversized. I was not confident in the team that redesigned the system so I have been suspect for a couple of months. The change took place long before I started working here so I did not know the history. Thank you for your reply. I appreciate the input.

why not use an oil heating system coupled wit Oil temperature control units?