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Background Material: 2005-10-09 A Plant to Retrofit Three Diesel Generators with RYPOS Trap

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AN ACTIVE DIESEL EMISSION CONTROL SYSTEM

Amin Saeid , Osama Ibrahim and Frank DePetrillo
RYPOS, 3 Industrial Park Road, Medway, MA 02053


OBJECTIVE--
The objective of the ICAT project was to demonstrate the capability of the
RYPOS TRAP diesel emission control system to remediate particulate matter from diesel
exhaust. This report presents the results of a field demonstration of the RYPOS TRAP. This
demonstration was partially funded by the ICAT program of the California Air Resources Board.
The RYPOS TRAP is an actively regenerated diesel exhaust particulate trap that is self-cleaning
and automatic in operation.

RYPOS TRAP--
The RYPOS TRAP is a highly effective Diesel particulate filter for exhaust
emission control. The system consists of filter housing, flow control, electrical control circuit, and
removable filter cartridges. The trap itself is composed of fine metal fibers that are shaped into
filter elements and then incorporated into filter cartridges; these sintered fibers are capable of
capturing the very fine carbon particles present in the exhaust stream. It can be used alone or in
conjunction with a Diesel oxidation catalyst to reduce the soluble organic fraction, gaseous
hydrocarbons, and carbon monoxide while suppressing the formation of sulfate.
















It is an active regeneration system (controlled regeneration) with high efficiency and soot
holding capacity and is regenerated independently of the exhaust temperature. The filter
element is electrically heated while the exhaust flow is reduced, thereby saving considerable
energy during the regeneration cycle. Each element, which represents a small fraction of the
total filter, is regenerated individually to reduce the maximum amount of electrical energy
required. In a medium size engine (100-200hp), fuel penalty is less than 1% of the rated
horsepower of the engine.


The RYPOS TRAP also serves as a sound absorption device and can be designed to fit the
same envelope as the muffler or catalytic converter it replaces.

2
FIELD DEMONSTRATIONS--
The field demonstration consisted of a nine-month series of tests
on three electrical backup generators, all located in Riverside, CA. The generators were rated at
100 kW, 225 kW, and 350 kW. Measurements of the diesel emissions were made before
installation of the RYPOS TRAP, after installation of the trap, after accumulation of 100 hours of
operation under varying load conditions, and after removal of the trap. This provided an
accurate record of the performance of each RYPOS TRAP.

The demonstration showed that the RYPOS TRAP can effectively remove total particulate
matter from diesel exhaust, and regenerate (clean) itself reliably independent of engine exhaust
temperature or fuel sulfur content. During these demonstrations, the backpressure remained
within acceptable limits.

RYPOS TRAP on a
100 KW Caterpillar Diesel Generator
, Riverside, California.

Two RYPOS TRAPs on a 225kW
Caterpillar Diesel Generator
, Riverside, California.














3
MEASUREMENTS AND RESULTS

Before the installation of each of the RYPOS TRAPs, the following operation
characteristics of the diesel generator were monitored to help evaluate the performance
of the trap:
a. Engine load,
b. Engine Speed,
c. Exhaust temperature,
Exhaust samples were collected before and after the installation of the systems and the
Total Particulate Matter (TPM) measurements were used to evaluate the Traps
efficiency.

100 kW System

Load Efficiency
Idle
78%

40 kW
86%

80 kW
89%


225 kW System

Load Efficiency
Idle
85%

125 kW
86%

175 kW
91%


Figure 1 below shows the pressure profile of the 100 kW generator, running for a day.
The pressure measurements were taken every second. Different segments of the graph
depict different engine load settings:
1- Idle, for about 1 hour
2- 40 kW, for about 3.5 hours
3- 80 kW, for about 30 minutes.

Figure 2 shows the backpressure for the 225 kW generator, after the installation of the
RYPOS TRAP. As in Figure1, the following settings can be distinguished:
1- The first part shows the engine idling for about 30 minutes,
2- The second part, 125 kW for about 20 minutes
3- The third part, 175 kW for 20 minutes.
4
0
25
50
75
100
125
150
0
1
2
3
4
5
Time (hours)
P
r
essur
e
(m
Bar
)
Idle
40 kW Load
80 kW Load

Pressure Drop (mbar), 100 KW Caterpillar Diesel Generator, May 13, 2002.



0
10
20
30
40
50
60
70
80
0
0.25
0.5
0.75
1
1.25
Time (Hours)
Pressu
re (
m
Bar)
Idle
125 kW Load
175 kW Load


Pressure Drop (mbar), 225 KW Caterpillar Diesel Generator, May 17, 2002.


5
Energy Penalty

100 kW Generator

Setting Regeneration
duty
cycle
Energy
Consumption
Energy Penalty
(%)
Idle 20%
0.3
kW
NA
40 kW
35%
0.53 kW
1.3%
80 kW
50%
0.75 kW
0.9%



225 kW Generator

Setting Regeneration
duty
cycle
Energy
Consumption
Energy Penalty
(%)
Idle 10%
0.3
kW NA
125 kW
20%
0.6 kW
0.5%
175 kW
30%
0.9 kW
0.5%


350 kW Generator

Setting Regeneration
duty
cycle
Energy
Consumption
Energy Penalty
(%)
Idle
20%
0.6 kW
NA
50 kW
33%
1.0 kW
2.0%
150 kW
100%
3.0 kW
2.0%

The Energy Penalty reflects the percentage of average power consumption needed to
regenerate as compared to the power generated by the engine. Notice that for both the
100kW and 225kW generators at Idle, the PM production is minimum, which results in
the minimum regeneration duty cycle. As the PM production increases, the
regeneration duty cycle increases from about 20 to 50% for the 100kW generator and
from 10% to 30% for the 225kW generator.
The system used in the 350 kW generator was under-sized on purpose to help us
optimize our design, this resulted in higher regeneration duty cycle and relatively high
energy penalty.

Conclusions
The completion of the ICAT demonstration program has shown that the RYPOS TRAP
is a viable solution to the problem of particulates in the exhaust of diesel engines
operated under low exhaust temperature or high sulfur fuel conditions. During this
demonstration program, the RYPOS TRAP maintained consistently low back pressure
under a variety of engine loads, and stayed within our target for regeneration efficiency.