Model

Zinc oxide desulfurization adsorbent  (ZnO Catalyst)

Color

White or light yellow

Shape

extrude

Normal size(mm)

Φ4×4--15

Bulk Density(kg/L)

1.0-1.3

Crushing strength(N/cm)

≥50

Loss on Attrition(%)

≤6

Breakthrough sulfur capacity, wt%

≥28(350℃)
≥15(220℃)
≥10(200℃)

Pressure, MPa

ambient to 4.0

Temperature ℃

180-400

Space velocity, h-1

1000-2000(gas)

Sulfur in feed gas, mg/m3

1-20 (≤200℃)
20-100 (≤250℃)

Sulfur in treated stream, ppm

max0.1

Loading

Loading depth: Higher L/D (min3) is recommended. Configuration of two reactors in series can improve utilization efficiency of the adsorbent.
Loading procedure:
(1)Clean the reactor before loading;
(2)Put two stainless grids with smaller mesh size than the adsorbent;
(3)Load a 100mm layer of Φ10—20mm refractory spheres upon the stainless grids;
(4)Screen the adsorbent to remove dust;
(5)Use special tool to ensure evenly distribution of the adsorbent in the bed;
(6)Inspect uniformity of the bed during loading. When inside-reactor operation is needed, A wood plate should be put on the adsorbent for the operator to stand upon.
(7)Install A stainless grid with small mesh size than the adsorbent and a 100mm layer of Φ20—30mm refractory spheres at the top of the adsorbent bed so as to prevent entrainment of the adsorbent and ensure even distribution of the gas stream.
Note: Evenly distribution of the adsorbent is essential to its efficient operation, which should be paid close attention to.

Start-up

(1)Replace the system by nitrogen or other inert gases until oxygen concentration in the gas is less than 0.5%;
(2)Preheat the feed stream with nitrogen or feed gas under ambient or elevated pressure;
(3)Heating speed: 50℃/h from room temperature to 150℃ (with nitrogen) ; 150℃ for 2 h (when heating medium is shifted to feed gas ),  30℃/h over 150℃ until required temperature is attained.
(4)Adjust the pressure steadily until the operation pressure is attained.
(5)After pre-heating and pressure elevation, the system should first be operated at half load for 8h. Then raise the load steadily when operation becomes stable till full-scale operation.

Shut-down

(1)Emergent shut-down
Cut feed gas (oil) supply. Close inlet and outlet valves. Keep the temperature and pressure. If necessary ,use nitrogen or hydrogen-nitrogen gas to maintain the pressure to prevent negative pressure.
(2 ) Change-over of desulfurization adsorbent
Close inlet and outlet valves. Steadily lower the temperature and pressure to ambient condition. Then isolate the desulfurization reactor from the production system. Replace the reactor with air until oxygen concentration of >20% is attained. Open the reactor and unload the adsorbent.
(3) Equipment maintenance (overhaul)
Observe the same procedure as shown above except that pressure should be lowered at 0.5MPa/10min and temperature lowered naturally.
The unloaded adsorbent shall be stored in separate layers. Analyze the samples taken from each layer to determine status and service life of the adsorbent.

Transportation and storage

(1)The adsorbent product is packed in plastic super sacks or iron barrels with plastic lining to prevent moisture and chemical contamination.
(2)The adsorbent product should be prevented from contact with chemicals during transportation and storage.
(3)The product can be stored for 3-5 years without deterioration of its properties if appropriately sealed.