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RE: RE: refineries



Bob, you raise a valid point, but with all due respect, without looking at a
lifecycle trade-off, I'd hate to walk away from significant energy savings
(and all of the resultant reductions in NOx, CO2, and fuel value) merely for
a *potential* concern over fouling related wastes.  Energy integration of a
refinery can lead to significant reductions in overall energy load so the
amount of reductions in these wastes/emissions can be very significant.  

While fouling is a potential source of waste in any process environment,
many heat exchangers operate in regimes of flow, fluid properties, and
design such that fouling-related wastes can be significantly reduced or
eliminated; further, some of the plate and frame designs and other
exchangers designed to promote high turbulence can reduce fouling even in
environments which otherwise might pose problems.  

Rather than dismiss energy integration (by whatever method) outright, a
better approach might be to use pinch (or your favorite energy optimization
method -- there are other approaches that will produce good results) to
identify improved efficiency HX networks, then use a DfE screening approach
to selectively implement the projects based on heat exchange scenarios, and
to select heat exchange equipment appropriate to the processing environment,
from a full lifecycle (including routine maintenance) perspective.   

The articles/checklists I suggested in my original post discuss design
strategies for dealing with fouling-related wastes (including equipment
design and materials selection, etc), but ignoring energy integration
opportunities is probably NOT a good strategy for eliminating these wastes.


SB

-----Original Message-----
From: Robert Pojasek
To: p2tech@great-lakes.net
Sent: 5/19/01 10:16 AM
Subject: Fwd: RE: refineries

You must be very careful using PINCH technology.  It helps flatten the 
energy curves by adding additional heat exchange devices.  These devices

get fouled (reduced heat transfer capacity) and need to be cleaned 
often.  This cleaning creates additional hazardous waste.  While it is 
possible to reduce energy and lower benzene emissions, you must trade
off 
this increase in hazardous waste.  I am not sure that the trade-off is a

good one.  This was examined in the EPA-Amoco Yorktown Refinery project 
and, I believe, PINCH was NOT implemented.  The developers of the 
technology fail to tell you about the tradeoffs.  So who said P2 is 
easy?  This is a great example of energy reduction expertise operating 
independently of pollution prevention expertise.  One should not
separate 
these items in practice.  However, it is often done.

Bob Pojasek

>Delivered-To: p2tech-outgoing@glc.org
>Delivered-To: p2tech@great-lakes.net
>Date: Fri, 18 May 2001 14:13:49 -0700
>From: "Butner, Robert S" <butner@BATTELLE.ORG>
>Subject: RE: refineries
>To: 'Dana Codell' <danacode@engr.colostate.edu>,
>         p2tech@great-lakes.net
>X-Mailer: Internet Mail Service (5.5.2653.19)
>Sender: owner-p2tech@great-lakes.net
>Reply-To: "Butner, Robert S" <butner@BATTELLE.ORG>
>List-Name: p2tech
>X-Loop: p2tech
>
>Dana --
>
>though you may need to use a specialist to help you with the
methodology, if
>the refinery has not already done so they should consider evaluating
the
>plant using the so-called "Pinch" technology (see for example,
>http://www.linnhoffmarch.com/Resources/WhatIsPinch/pinint1.htm).  The
method
>was pioneered by B. Linhoff, but has been applied and extended by
numerous
>others and is essentially a thermodynamic analysis method for
identifying
>opportunities for heat recovery in complex process plants.   This can
often
>be a very effective means of identifying significant energy use
reductions
>in plants, and has the advantage of a fairly high degree of industrial
>acceptance.

Bob

Dr. Robert B. Pojasek
Pojasek & Associates
PO Box 1333
E. Arlington, MA 02474-0071
(v) 781-641-2422
(f)  617-788-0288


http://www.Pojasek-Associates.com
rpojasek@sprynet.com