MECS CATALYST PRODUCTS & TECHNICAL SERVICES UPDATE Presented By: Chris D. Winkler MECS, Inc. St. Louis, Missouri, U.S.A.
2 opics Brief History Standard Catalyst Composition MECS Standard Catalyst Products Factors Affecting Catalyst Life Temperature Memory Effects in Catalyst Caesium-promoted Catalyst Composition MECS Caesium Catalyst Products Caesium Catalyst Applications & Benefits MECS Technical Services Summary Q&A
3 istory Original sulphuric acid catalysts were silica supported, platinum (Pt) based. + active at low temperatures - easily poisoned ; very expensive Shift in the early 1900 s to Vanadium-based catalysts utilized for oxidizing SO 2 to SO 3. MECS manufacturing vanadium-based catalysts since 1925. Evolution from pellets to energy saving rings to the low emission, caesium-promoted catalysts offered today. MECS has maintained a worldwide leadership position in the supply of sulphuric acid catalysts.
Standard Catalyst Composition 4 Catalyst Components Diatomaceous Earth (SiO 2 ) + Vanadium (V) Salts + Potassium (K)
5 olten Salt Chemistry K 2 S 2 O 7 + V 2 O 5 K W V X S Y O Z Salt compound liquefies under reaction conditions (> 350 C). Molten salt composition is variable; hence, the generic labeling of w, x, y and z. No Vanadium Pentoxide is Present!
6 ECS Standard Catalyst Products CORE The XLP six-lobed, ribbed-ring line of catalysts offer extended surface area and lowest pressure drop. XLP-220 (Beds 1 and 2) XLP-110 (Beds 2, 3, 4 and 5)
7 ECS Standard Catalyst Products CORE The LP raschig-ring line of catalysts offer low pressure drop and high activity. LP-120 (Beds 1 and 2) LP-220 (Beds 1 and 2) LP-110 (Beds 2, 3, 4 and 5)
8 ECS Standard Catalyst Products Non-CORE The T pellet lines of catalysts are most suitable for low gas velocity converter designs. T-210 (Beds 1 and 2) T-11 (Beds 2, 3, 4 and 5)
9 actors Affecting Catalyst Life CAUSE Dust Accumulation Iron Oxide Scale Oxychloride Formation Moisture Contact Poisons (e.g. As, oxide coatings) Fluorine Attack Thermal Cycling RESULT Vanadium Loss Leaching of Active Salts Decrease in Hardness Lower Activity Carrier Degradation
10 emperature Memory Effects in Catalyst Concern is that raising the bed inlet temperature will result in loss of activity at lower temperature operations. Activity loss only occurs if the catalyst has been exposed to temperatures >100 C above typical operating temperatures for a prolonged period (> 7 days). Damage is more physical than chemical in nature. At elevated temperatures, the structure of the catalyst support changes resulting in a decrease in surface area. Never move catalyst from bottom of Bed 1 to top. Chemical effects are impacted by the composition of the active phase. Highly sulfated lower bed catalysts perform well in upper beds but not visa versa. Never move catalyst down the converter (i.e. Bed 3 to 4)
Caesium-promoted Catalyst Composition 11 Catalyst Components Diatomaceous Earth (SiO 2 ) + Vanadium (V) Salts Potassium (K) Cesium (Cs) Still Contains Vanadium!
12 ECS Caesium Catalyst Products + Reduced Ignition Temperatures + Lower Plant Emissions Six-lobed, ribbed ring: XCs-120 (All Beds SCX-2000 (Beds 4 and 5) Raschig ring: Cs-120 (Beds 1 and 2) Cs-110 (Beds 2, 3, 4 and 5) Pellets available upon request.
13 aesium Catalyst Applications & Benefits Reduced First Bed Inlet Temperatures As low as 360 C (optimal performance 390 410 C) 30 50% cap of caesium on top of standard catalyst Cs catalysts do not provide additional activity benefit at temperatures much above 420 C Illustration on next slide Plant Re-Start Following Shutdowns Caesium in first and last passes can eliminate need for pre-heater upon re-start Savings in time and fuel costs! Reduction of SO 2 emissions (Single / Double Absorption) <100 ppm achievable with use of SCX-2000 in DCDA plants Illustration forthcoming Control of First Bed Outlet Temperatures Cs cap provides for reduced inlet temperature and lower outlet temperature while maintaining conversion performance
14 educed First Bed Inlet Temperatures Cs Catalyst Advantages 120 100 Equilibrium Curve % SO 2 CONVERSION 80 60 40 XCs-120/LP-120 / XLP-220 XLP-220 LP-120 20 0 380 430 480 530 580 630 680 TEMPERATURE ( C)
15 eduction in SO 2 Emissions Double Absorption 150 Metallurgical Plant; 10.5% SO 2, 11.5% O 2 Same 4th Bed Loading for Each Catalyst SO 2 Emissions (ppm) 100 50 0 130 XLP-110 (420 C) 55 SCX-2000 (390 C) 4th Bed Catalyst
16 ECS Technical Services Catalyst Sample Analysis Activity Hardness Computer Simulation Studies: SO2OPT Portable Gas Analysis: PeGASyS Gas chromatography-based Solve conversion problems Identify heat exchanger leaks Increase sulphuric acid productivity World Leading Expertise in Sulphuric Acid Processes and Technology
17 ummary Discussed the basic fundamentals of standard potassium and caesium-promoted sulphuric acid catalyst formulations Composition and salt chemistries Reviewed factors that affect catalyst performance Dust accumulation, moisture contact, poisons, etc. Presented MECS standard and caesium-promoted catalyst products XLP, LP, XCs, SCX and pellet lines Introduced a variety of applications for caesium catalyst with examples given to assist in quantifying the associated benefits Reduced ignition temperatures, lower emissions, etc. Update on MECS Technical Services extended today Sample analysis, SO2OPT, PeGASyS, Sulphuric expertise
Questions & Answers Thank You!!!