Zinc oxide desulfurization adsorbent catalyst for chemical

Zinc oxide desulfurization adsorbent catalyst for chemical
HL-306 is applicable to desulfurization of residue cracking gases or syngas and purification of feed gases for
organic synthesis processes. It is suitable for both higher (350--408°C) and lower(150--210°c) temperature use.
It can convert some simpler organic sulfur while absorbing inorganic sulfur in gas stream. Main reaction of the
desulfurization process is as follows:
(1) Reaction of zinc oxide with hydrogen sulfide H2S+ZnO=ZnS+H2O
(2) Reaction of zinc oxide with some simpler sulfur compounds in two possible ways.
Physical Properties
Appearance
white or light-yellow extrudates
Particle size , mm
Φ4x4--15
Bulk density, kg/L
1.0-1.3
Quality Standard
crushing strength, N/cm
≥50
loss on attrition, %
≤6
Breakthrough sulfur capacity, wt%
≥28(350°C)≥15(220°C)≥10(200°C)
Normal Operation Condition
Feedstock : synthesis gas , oil field gas, natural gas, coal gas. It can treat gas stream with inorganic sulfur as high
as 23g/m3 with satisfactory purification degree. It can also purify gas stream with up to 20mg/m3 of such simpler
organic sulfur as COS to less than 0.1ppm.
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.
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°C/h from room temperature to 150°C (with nitrogen) ; 150°C for 2 h (when heating medium is
shifted to feed gas ), 30°C/h over 150°C 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 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 loweredat 0.5MPa/10min and temp.
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 or iron barrels with plastic lining to prevent moisture and chemical
contamination.
(2)Tumbling, collision and violent vibration should be avoided during transportation to prevent pulverization of the
adsorbent.
(3)The adsorbent product should be prevented from contact with chemicals during transportation and storage.
(4)The product can be stored for 3-5 years without deterioration of its properties if appropriately sealed.