Catalysis 2024 Issue

Alternatively, haziness can be measured by ASTM D4176, P-2 (visual examination of fuel by numer- ical rating method) or ASTM D4860 (spectropho- tometric method). Table 2 represents the results of the same sample by different test methods. Observations: The test results per ASTM D4176, P-1 do not represent the intensity of haze, while ASTM D4176, P-2 and ASTM D4860 produce numerical ratings proportional to the intensity of haze. Also, the numerical results of both test methods correlate according to the intensity of the haze. Study on haze stability Aim: To evaluate the time required to make the diesel sample clear from hazy. Theoretically, haze is influ - enced by fuel composition and storage time. During storage, water settles, improving the haziness. Hence, it is very important to check the sample’s haze stability to determine the downstream effect and take necessary measures to control the haziness of the upstream unit. Exp. conditions: Different diesel samples were ini- tially evaluated for haze rating per ASTM D4176, P-1 and P-2. Samples with a 2-6 haze rating were used,

Results of haziness by different test methods

Sample ASTM D4176, P-1 ASTM D4176, P-2

ASTM D4860

Sr. No.

(Visual)

(Spectrophotometry)

Clear and bright

Rating scale 1 (Clear) to 6 (Most hazy)

Rating scale 100 (Clear) to 50 (Most hazy)

or hazy

1 2 3 4 5 6 7 8 9

Clear and bright Clear and bright Clear and bright Clear and bright

1 1 1 1 3 2 2 2 2 3 3 3 4 4 6 6

100

96 97 73 94 88 91 85 78 75 75 71 66

100

Hazy Hazy Hazy Hazy Hazy Hazy Hazy Hazy Hazy Hazy Hazy Hazy

10 11 12 13 14 15 16

<50 <50

Table 2

test methods and moisture content. It was then divided into two parts, with one part stored in a glass bottle and the sec- ond in an aluminium bottle to check the effect of the storage container on settling time, if any. Both samples were tested intermittently for moisture and haze by all three test meth- ods until the sample became free of haze (CB appearance). Test results: The hazy diesel sample has a 6 haze rating per ASTM D4176, P-2. Stored in the aluminium bottle, it took 96 hours to reach the haze-free rating of 1, while the sample stored in the glass bottle took only 22 hours. Observations: The test results clearly show that the sample stored in the aluminium container takes much more time to become haze-free or BC in appearance. This indicates that storage containers highly impact the stability of haziness. Moisture vs haziness correlation study Aim: To develop the correlation between moisture content vs haziness rating by ASTM D4176, P-2 and ASTM D4860. ASTM D4860 is an instrumental method in producing digital test results in the scale of 50-100, while ASTM D4176, P-2 is a visual rating method producing a numerical rating on a scale of 1-6.

and the settling time was recorded until the sample became CB or a haze rating of 1. The experiment was conducted at 25ºC inside the laboratory. Test results: Diesel samples with initial haze ratings of 2, 3, 4, 5, and 6 become CB or haze rating of 1 after six, nine, 23, and 96 hours, respectively. Observations: The haze stability study data show that die- sel samples with a higher haze rating by ASTM D4176, P-2 required more time to achieve a haze-free rating of 1 or CB appearance. The test results of ASTM D4176, P-2 showed better clarity of haze intensity than P-1. These test results will be very helpful in avoiding product failure by taking pre- ventive measures upstream or downstream. A diesel sample with a haze rating of less than 3 may become clear within a product certification time of approximately 12 hours, while a haze rating of more than 4 may lead to product failure. Impact of sample storage container on haziness Aim: To evaluate the impact of storage containers on haziness. Exp. condition: In this experimental work, the DHDS dryer feed sample collected from the unit exhibits the highest haze. The sample was first tested for haziness by different

Correlation of Moisture vs Haze Rating by D4176, P-2

3B Correlation of Moisture vs Clear & Bright Rating by D4860

50 80 70 60 90 100

0 3 2 1 4 5 6

100

200

300

400

500

100

200

300

400

500

Moisture (ppm)

Figure 3 Moisture vs haziness correlation study test results

Catalysis 2024