Electric Thermal Fluid Heaters.
Electrically heated thermal fluid systems are extremely useful for heat
processing applications, but regular contributor Jay Hudson, P.E., cautions
that the user should understand what’s “inside the box” when specifying and
purchasing this equipment. In this installment of his six-part series on
specifying a thermal fluid system, Hudson, who is president of a consulting
firm, J.G. Hudson &Associates, based in Salisbury, N.C., provides an overview
of the general types of equipment available as well as the details of construction
to look for.
Multi-Zone SCR Power Control. By using
multiple zones of heat control, you put the heat where it is needed most. So
says George A. Sites, director of engineering at Ametek HDR Power Systems,
Columbus, Ohio. Sites describes applications that lend themselves to multi-zone
control as well as those better suited to single zones of control. For those
applications that suit multi-zone control, however, the method provides a
sophisticated means of managing your process equipment.
Heat Recovery Using Plate Heat
Exchangers. Though in the past, many processors regarded heat
recovery as not worth the capital expenditure, with today’s high energy costs,
they’re taking a second look, according to Cheryl J. Shoemaker, a senior
application engineer with APV North America in Getzville, N.Y. Shoemaker notes
that plate heat exchangers designed for heat recovery can be specifically
configured to meet the duty, taking into account the product characteristics.
Heat recovery even is possible with two different products or with uneven
flows. What is key, Shoemaker says, is capturing the heat before it is
Functional Safety for Instrumented
Systems. The global importance of safety-integrity levels (SILs)
has grown substantially in the oil/gas, petrochemical and other process
industries over the last 10 years. However, for many end users, systems
integrators, and even product vendors, SIL is still a somewhat ambiguous
concept that often is misinterpreted and incorrectly implemented, say engineers
from General Monitors Inc., Lake Forest, Calif. Intended as a primer on SIL,
the article notes that a safety instrumented system (SIS) is designed to
prevent or mitigate hazardous events by taking a process to a safe state when
predetermined conditions are violated.
Equipment Overview on Dryers. Rounding
out the lineup of feature articles this month is our annual bullet chart on
dryer manufacturers. This comprehensive selection guide can ease the dryer
specification process by identifying manufacturers with the experience you
desire. Also offered online at www.process-heating.com, the guide is a
year-round reference worth retaining.
Associate Publisher and Editor