Passive, Active, or Load Bank?:

The Case for Improved Diesel Particulate Filtration

by Daniel Serrano and Daniel Williams
Peterson Power Systems

Your passive diesel particulate filter (DPF) may be on the verge of failure. Since 2004, when major legislation caused most California businesses to scramble to meet compliance, facilities managers, business owners, and power generation technicians have installed thousands of passive DPF units on stationary engines across the state. However, many operators have neglected (or been unable to initiate) the maintenance procedures specific to these units, and for many, catastrophic failure lurks around the corner.

This paper explains why passive units fail, and the benefits of augmenting or upgrading your facility’s passive DPFs to avoid costly repairs to your stationary diesel engine’s DPF system—or the engine itself. This paper will specifically discuss passive DPF technology, load banks and their applications, and characteristics of active DPF technology; address potential maintenance issues inherent to either system; and offer practical advice to facilities managers and business owners on choosing a service provider for their equipment.

Determine Your Needs

The first step in actively managing your facility’s DPF needs is to determine the proper filtration system for your organization. How often do you operate your stationary engine? What is your budget? How frequently will you service your DPF unit?

A thorough survey of your facility’s energy needs and examination of your current maintenance schedule with a qualified service provider should be your first step in determining your needs. A representative from a qualified provider will be willing to visit your site, examine your equipment, and address your concerns. Your provider’s technician will evaluate your filters to check for accumulated PM and to determine if they are regenerating as needed. If necessary, he or she will also recommend corrective action or additional equipment.

Load Bank Technology

When attached to your passive DPF system, a load bank will simulate the conditions found in a generator operating near full capacity; the high heat will allow regeneration to occur within your DPF, and the PM trapped inside will disintegrate and exit the system. In most cases, periodic use of a load bank on your DPF will be sufficient to keep it unblocked. Your budget will determine whether you install a load bank permanently or arrange for a service provider to perform the operation on a scheduled basis, but either option should suffice, provided you follow the specific maintenance requirements recommended by your DPF’s manufacturer.

Active Filtration

An active DPF system differs most crucially from its passive counterpart in that it uses an electric current to incinerate diesel particulate trapped in its filter. This electric type is the only option for stationary engines at this time—there are other types of technology that use diesel fuel to create a flame inside the DPF unit which will sufficiently increase exhaust temperature, but these are only available in California for on-road and off-road mobile applications. Unlike a passive system, an active DPF requires no engine heat or exhaust to operate effectively, and as such, is not subject to the same load requirements as a passive system that has not been augmented with a load bank.

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