RC CATALYTIC CONVERTER INSTALLATION, OPERATION AND MAINTENANCE

Transcription

1 RC CATALYTIC CONVERTER DCL International Inc. P.O. Box 90, Concord, ON, Canada Phone: Toll Free: Fax: RC CATALYTIC CONVERTER X

2 TABLE OF CONTENTS 1. GENERAL NAMEPLATE INFORMATION PRODUCT DESCRIPTION General Product Description Catalyst Substrates Design Features: RC Oxidation Catalytic Converter INSTALLATION Mounting the Converter Installation and Removal of Catalyst Substrates (Side Load) Installation of Catalyst Substrates (Top Load) Mounting Examples Leak Test Long-Term Shut-Down of Engine Safety, Storage and Handling of Catalyst Substrates OPERATION Operating Requirements Exhaust Gas Temperature Modes of Catalyst Activity Loss MAINTENANCE TROUBLESHOOTING SPARE PARTS LIST... 21

3 1. GENERAL Important Note: Before any work, consult your company health and safety officer for details of safe working practices. Safety requirements include but are not limited to: proper engine shut down; personal protection (gloves, coveralls, safety glasses etc.); and safe handling temperature of converter. The RC catalytic converter is designed for emission control of industrial internal-combustion engines used in the following applications: Power generation and co-generation Gas compression Chillers Irrigation and pumping stations This manual contains instructions on installation, maintenance and operation of the converter*, as well as operating limits and restrictions. For lean-burn spark-ignited or compression ignited engines the converter promotes the oxidation reactions of carbon monoxide (CO), hydrocarbons (C x H y ) and partially oxidized hydrocarbons (C x H y O) into carbon dioxide (CO 2 ) and water (H 2 O). For these reactions to take place the catalyst substrate must have a coating designed for oxidation reactions. The converter is normally used for allowing a site to comply with air quality requirements. The design conversion efficiency and/or design post-converter emissions are provided in the Quotation. The conversion of any of substance across the converter shall be the difference of the inlet quality of the substance minus the quantity of the substance divided by the inlet quantity of the substance. In some cases the converter is combined with a muffler or silencer to also provide sound attenuation. *The term converter (unless otherwise specified) will be used in this manual to include both RC catalytic converters and RC catalytic silencers installed with either oxidation or three-way catalysts. RC CATALYTIC CONVERTER 1/20

4 2. NAMEPLATE INFORMATION Refer to the nameplate for the part and serial numbers. Nameplates are located on the housing and the catalyst substrate has a serial number. Record this information for reference. Figure 2.1 Nameplate for housing RC CATALYTIC CONVERTER 2/20

5 Part Number Serial number RC CATALYTIC CONVERTER 3/20

6 3. PRODUCT DESCRIPTION 3.1 General Product Description The converter is made up of several components: the housing, the catalyst substrates and the inlet and outlet connection flanges. The converter housing is designed with specific geometric shapes and airflow characteristics. The housing also provides structural support and stability to the oxidation catalyst substrates, which are the part of the converter where the catalytic reactions take place that result in destruction of pollutants. The catalyst substrate is a structure of metal foils with active catalyst material coated on the surface. 3.2 Catalyst Substrates The substrate is made up of high-temperature-resistant stainless steel foils of alternating layers of corrugated and flat strips, providing parallel flow-through channels for exhaust gas. Exhaust gas passing through the channels contacts the surface, where catalytic chemical reactions take place. Catalytic materials coated onto the surfaces of the channels consist of a refractory inorganic oxide, various substances that act as chemical promoters and stabilizers, and a combination of platinum group metals that can include platinum, palladium and rhodium. The substrate has an outer stainless steel frame that provides rigidity. An RC housing contains a number of substrates arranged together, depending on the configuration. RC substrate 300 x 600 x 94 mm 300 x 300 x 94 mm The number of flowthrough channels in a substrate is 100, 200,300 or 400 cpsi (cells per square inch). This provides a high geometric contact surface for the exhaust gas. Stainless Steel Frame (16GA 439 SS) Figure 3.1 RC Catalyst Substrates RC CATALYTIC CONVERTER 4/20

7 3.3 Design Features: RC Oxidation Catalytic Converter The converter is installed on the engine s exhaust pipe, using flanged connections. A housing cover provides access to the catalyst substrate(s) for inspection, maintenance and catalyst substrate replacement. The housing cover for the catalyst substrate has a positive seal bolt pattern on its perimeter. A graphite gasket provides a seal between the housing cover and the housing. Sampling ports are provided at the inlet and outlet cones of the housing to allow for measurements of emissions, temperature, temperature rise ( T) and pressure drop ( P). A DCL identification plate provides manufacturer reference material. A number of substrates come pre-assembled into the housing support frame. Body Frame Converter Cover Connecting Flange Sampling Port Connecting Flange Dispersion Panel (On some designs) Converter Cover Bolt Catalyst Substrate Figure 3.2 Cut Away View of the RC Converter Housing and Catalyst Substrates RC CATALYTIC CONVERTER 5/20

8 4. INSTALLATION 4.1 Mounting the Converter General Mounting Guidelines The converter should be mounted so that it is isolated from engine vibration and external loading due to the weight of the unit or thermal expansion. The converter housing is not designed as a structural member and excess torsion, compressive and tension stress should be avoided. The following are additional guidelines for mounting the converter: Mount the converter in horizontal flow orientation as shown in figure 4.1 The converter is to be mounted by base support in a horizontal position. Always put an expansion joint between the engine and the beginning of the exhaust piping, in order to isolate the converter from engine vibration. Ensure the converter does not support the weight of the exhaust pipe or any other exhaust system components. Avoid long piping runs before the converter, as it will thermally expand into the housing. If commissioning or first start-up of the engine is expected to result in misfiring, or excessive vibration, the catalyst substrates should be removed from the housing during this stage. Ensure mounting lid is properly installed as per the instructions in section 4.2 below. Selecting a Location The inlet gas temperature entering the converter should be as high as possible in order to increase conversion efficiency of pollutants; however, in order to avoid thermal damage to the converter materials, the exhaust temperature should not exceed 680 o C (1250 o F). Most modern diesel, dual fuel and lean-burn SI engines have exhaust temperatures well below this limit. It is therefore recommended, in most cases, that the converter be mounted as close as possible to the exhaust manifold or to the turbocharger outlet. To minimize temperature loss prior to the converter inlet, avoid lengthy un-insulated exhaust pipes prior to the converter and mount the acoustic silencer downstream of the converter. Ensure that the converter location is easily accessed for inspection and removal of the substrate(s). Where necessary, install non-slip walking grids and/or safety railings for accessing the catalyst substrate. If in doubt about the proper location for the converter, or if temperature drop estimates are required for various pipe lengths, contact DCL for assistance. RC CATALYTIC CONVERTER 6/20

9 Exhaust gas direction Ground Figure 4.1 Flow Orientation of the RC converter For best mechanical durability of the catalyst substrate the housing must be positioned so that the exhaust flow direction is parallel with the ground. 4.2 Installation and Removal of Catalyst Substrates (Side Load) Installing Housing Lid Step Description 1. To install the housing lid insert top and bottom pins into both hinge support holes as shown below. RC CATALYTIC CONVERTER 7/20

10 Removal of Catalyst Substrate Step Description 1. Remove the bolts from the housing cover and swing open the housing door. 2. Remove the first divider by releasing it from the top and bottom slots. First Divider 3. Remove first column of substrates starting from the top substrate and working your way down. 4. Repeat steps 2 and 3 until the last column of substrate is removed. RC CATALYTIC CONVERTER 8/20

11 Installation of Catalyst Substrates Step Description 1. Remove the bolts from the housing cover and swing open the housing door. 2. Roll and attach self-glued wire mesh around holder. 3. Apply wire mesh assemblies on the specified locations downstream of the catalyst substrate. Push and secure the wire mesh assemblies against inside edges of top and bottom channels (outlet side) and inside of all divider s edges (outlet side). RC CATALYTIC CONVERTER 9/20

12 4. Apply wire mesh to the bottom of the catalyst substrate 5. Vertically install the first column of catalyst substrates per the configuration below, starting from layer 1. Load other layers if required. 6. Install the first divider couple securing it at the top in the slot provided. Install subsequent columns and dividers as required. RC CATALYTIC CONVERTER 10/20

13 7. Secure the last single divider in the slots located at the top and bottom. Install the gasket segments as shown. 8. Close the housing lid and install the bolts, flat washers, lock washers and nuts. Torque nuts to about 150 lb-ft. 9. Follow leak test instructions in section 4.5 below RC CATALYTIC CONVERTER 11/20

14 4.3 Installation of Catalyst Substrates (Top Load) 1. Loosen the bolts, attach the slings to the 4 lift lugs on top of the lid and remove the lid from the housing with an overhead crane or lift truck with sufficient capacity. Lift lugs 2. Inspect the catalyst module for any damage such as bent module frames, damaged catalysts etc. prior to installation. Report any deviation or damage to DCL. 3. Lift the catalyst module one at a time and put them vertically down into the housing starting at the end closest to the exit (layer 1). 4. If required, install catalyst module in other layers closest to the exit end. Install the gasket segment as shown below. Check the gasket all the way around the flange for any damage. RC CATALYTIC CONVERTER 12/20

15 5. Close the housing lid, install the bolts, flat washers, lock washers and nuts. Torque nuts to 150 lb-ft 4.4 Mounting Examples The RC Catalytic Converter is available with or without cones installed. Converter with Cones Converter without Cones (Installed in customer supplied housing or muffler) RC CATALYTIC CONVERTER 13/20

16 4.5 Leak Test If the converter is located in-doors, leak testing should be conducted on a regular basis, including during initial start-up and any time after the housing cover is opened for servicing of the catalyst substrates. See Table 6.1 for a maintenance schedule. Follow the steps below for conducting a leak test. Step Description 1 Operate the engine under high load conditions, without insulation on the housing. 2 Place a piece of light non-combustible cloth-like material on the edge of a pole and move the cloth next to the sealing points of the housing (i.e., connection flanges and housing cover). 3 If movement of the cloth is detected, shut down engine and review sections on installation of catalyst substrate(s). 4 If no movement of cloth is detected, shut down the engine and complete the installation of the insulation material once exhaust system has cooled down. 5 Check for leaks on a regular basis according to the maintenance schedule provided in Table 6.1. Note: In order to minimize leaks, ensure that the total exhaust system back-pressure does not exceed the maximum recommended by the engine manufacturer. 4.6 Long-Term Shut-Down of Engine If long term shut-down of the engine for several months takes place, care should be taken preserve the integrity of the housing and the catalyst inside. The substrates may remain inside the housing during the period of long-term storage, if the housing cover plate is properly installed and tightly sealed. If the housing is installed in an out-door location, it must be covered and protected from the weather. Avoid the build-up of water inside the housing. Cover the exhaust pipe so that no moisture or debris enters into the exhaust and collects on the catalyst substrates. 4.7 Safety, Storage and Handling of Catalyst Substrates Handling the DCL metal substrates does not pose any particular health or safety hazard related to catalyst composition or formulation (see MSDS sheets). The metal foils are sharp and abrasion of the hands or other body parts may occur if the substrates are handled without gloves or other protective clothing. Anyone handling DCL substrates should ensure that all work is carried out in a safe manner in accordance with occupational health and safety and other applicable regulations. Consult your health and safety officer for details of safe working practices. RC CATALYTIC CONVERTER 14/20

17 DCL substrates should be handled and shipped as fragile items. The substrates should be packed in bubble wrap or other suitable packing material. The thin metal foils on the substrate are prone to damage if handled improperly. The substrate foils can be easily crushed if struck with a hard object, resulting in plugging of the channels. If substrates are stacked together for shipping, use a layer of cardboard, plywood or other suitable material between each substrate to prevent them from rubbing against each other and causing damage. To store DCL substrates, pack the substrate in a plastic or bubble wrap and store at normal room temperature in a dry area away from direct sunlight. If stored under these conditions DCL substrates have an indefinite shelf life. It is recommended that parts stored in excess of two years be tested for activity before use. DCL should be contacted if activity testing is required. After prolonged storage some dust may accumulate at the bottom of the substrate. This dust will contain high levels of alumina and platinum group metals. This dust does not pose any health or safety hazard but should be disposed of properly. RC CATALYTIC CONVERTER 15/20

18 5. OPERATION 5.1 Operating Requirements Exhaust Flowrate Exhaust Temperature Engine Power Engine Speed Lube Oil Specification Lube Oil Consumption Rate Crank case ventilation Fuel Quality for Diesel, LFO, or Biodiesel blends Fuel Quality for Natural Gas or LPG Oxygen Ash Deposits Exhaust system Back-Pressure Catalyst Poisons As indicated in quote. Maximum 1112 o F (600 o C) at inlet to converter. Maximum 1112 o F (600 o C) at outlet of converter. As indicated in quote. As indicated in quote. Sulfated ash. <0.6 wt% Zinc < 900 ppm. Phosphorus < 400 ppm. Manufacturer s normal lube oil consumption rate or 0.5 g/bhp-hr (0.67 g/kw-h), whichever is lower. Crank case ventilation should be routed either back to the air intake or downstream of the converter. Fuel must conform to ASTM D975, ASTM D6751, EN590 or EN14214 standards, plus the following additional standards: Sulfur < 500 ppm. Chlorinated compounds must be Nil. Silicon compounds or siloxanes must be Nil Phosphorus < 1 ppm. Fuel must be pipeline quality natural gas or commercial LPG free of contaminants. For natural gas the energy content must be > 750 BTU/ft3 LHV Sulfur < 100 ppm. Chlorinated compounds < 10 ppm. Silicon compounds or siloxanes must be Nil. Biogas, sewage gas and digester gas is not acceptable, unless explicitly stated otherwise in quote. > 4% O 2 at inlet to converter. < 1 g/l (28 g/ft 3 ) of catalyst substrate. Remove ash by cleaning or vacuuming if necessary. High levels of ash on the substrate and reduce conversion efficiency. Exhaust system must be free of leaks. Converter back-pressure should not be allowed to increase more than 2 wc (0.5 kpa) over the clean converter back-pressure. This can indicate excessive build-up of ash deposits. The catalyst elements should be cleaned if this occurs. Catalyst poisons build up on the catalyst over time, due to their presence in the fuel or lube oil. Analysis of the catalyst substrate is done by removing a small section and conducting a chemical analysis at DCL or a qualified laboratory. For good performance, catalyst poisons on the catalyst washcoat shall not exceed the following. Sulfur < 1% Calcium < 1% Phosphorus < 1% Zinc < 0.5% Iron < 1% Sulfur, Calcium, Phosphorus, Zinc, Iron < 2% (collectively) Lead, Mercury, Arsenic, Antimony, Copper, Tin, Nickel, Chromium < 200 ppm (collectively) RC CATALYTIC CONVERTER 16/20

19 Where post-catalyst emissions statements are provided in the quote, temperature at the inlet to the converter is assumed to be as shown in the table below, unless explicitly stated otherwise in the quote. 5.2 Exhaust Gas Temperature Fuel Natural Gas Natural Gas Pollutant Non-methane hydrocarbons (NMHCs), including formaldehyde Non-methane, non-ethane hydrocarbons (NMNEHCs), including formaldehyde Volatile Organic Compounds (VOCs)* Min. Temperature at Inlet 842 o F (450 o C) 797 o F (425 o C) Natural Gas 797 o F (425 o C) Natural Gas Formaldehyde (CH 2 O) 752 o F (400 o C) LPG Total Hydrocarbons (THCs) 842 o F (450 o C) Diesel Total Hydrocarbons (THCs) 752 o F (400 o C) All types Carbon Monoxide 752 o F (400 o C) *VOCs are assumed to not include methane or ethane Limits to Exhaust Compositions Ethane < 40 wt.% of exhaust NMHCs Ethane + propane < 50 wt.% of exhaust NMHCs Propane < 10 wt.% of exhaust NMNEHCs Propane < 30 wt.% of exhaust THCs DCL at its sole discretion may void the product warranty if the following occurs: Engine misfires, backfires or exhaust system explosions Excess unburned fuel entering the catalyst, such as where engine operates over its lean limit or if ignition failure occurs Turbocharger failure Exhaust temperature in excess of maximums stated in the table on page 13 Catalyst poisons in excess of the maximum in the table on page 13 Fuel quality not meeting the specifications provided in the table on page 13 Mechanical damage due to improper mounting of the housing Mis-handling or improper storage of catalyst substrates Failure to conduct normal maintenance RC CATALYTIC CONVERTER 17/20

20 5.3 Modes of Catalyst Activity Loss The activity of the catalyst substrate will decrease over time, due to a variety of reasons described in Table 5.3. With loss in activity, conversion efficiencies will decrease over time. In some cases activity loss can be partially reversed by vacuuming or chemically washing the catalyst substrate (see Maintenance, section 6). Mechanism Description Poisoning Materials that chemically combine with the catalyst and reduce its activity are called catalyst poisons. Chemical poisoning of the surface coating of the catalyst substrate occurs as a result of poison materials in the exhaust gas. In most cases the damage is irreversible. Catalyst inhibition Catalyst inhibitors are materials that decrease catalyst activity when present in the exhaust under certain operating conditions, but no longer decrease activity when not present in the exhaust or if operating conditions change. (eg. under low temperature operation sulfur is a poison, but it is removed during high temperature operation). Fouling/Masking Fouling or masking occurs when the surface coating is blocked or plugged as a result of inert materials such as non-combustible ash. In many cases the inert material can be removed by cleaning, allowing catalyst activity to be restored. Thermal Deactivation Thermal deactivation occurs due to sintering or phase transformation of the surface coating as a result of excessively high temperature. Extreme temperatures will also destroy the metal foils. Thermal deactivation is always irreversible. Erosion and mechanical Erosion of the surface coating can occur due to age and wear. damage Mechanical damage may also cause nesting of substrate channels. The damage is irreversible. Table 5.3 Modes of Catalyst Activity Loss RC CATALYTIC CONVERTER 18/20

21 6. MAINTENANCE DCL s recommended monitoring and maintenance schedule during operation is given below. Due to large variations in operating conditions, the schedule may change depending on the specifics of the application. In addition to this schedule, additional monitoring and reporting may be needed according to the requirements of your environmental permit. It is recommended that a maintenance log is maintained. Measurements and records of temperature difference ( T) and pressure difference ( P) should always be made under the same operating conditions (e.g., engine load, speed, ignition timing and exhaust oxygen concentration). Item No. Description > 4000 hours operation per year hours operation per year <500 hours operation per year Directions 1 Check back-pressure ( P) 2 Check temperature change ( T) 3 Conduct emissions test At time of installation Every 3 months At time of installation Every 3 months As required by operating permit At time of installation Every 6 months At time of installation Every 6 months As required by operating permit At time of installation Every year At time of installation Every year As required by operating permit If the ( P) is more than 55 mm H 2 O (2 H 2 O) higher than the initial ( P), inspect catalyst for excessive ash buildup. See Section 7 (Troubleshooting). If the ( T) is more than 14 o C (25 o F) higher than the initial ( T), check the engine for misfiring, and/or inspect catalyst substrate for damage or fouling. See Section 7 (Troubleshooting). As required by operating permit. 4 Visual inspection of Every 2 years Every 3 years Every 3 years See Section 7 (Troubleshooting). catalyst substrate 5 Chemical cleaning of catalyst substrate Every 2 years Every 3 years N/A Contact DCL or authorized dealer for assistance. 6 Leak test of housing After opening housing cover Every 3 months After opening housing cover Every 6 months After opening housing cover Every year Conducting a leak test is only necessary if housing is insulated or if converter is located in-doors. See Section 4.3 for details on conducting a leak test. Table 6.1 Monitoring and Maintenance Schedule Note: Items 1, 2 and 3 can be conducted by utilizing the ports on the inlet and outlet side of the converter. RC CATALYTIC CONVERTER 19/20

22 7. TROUBLESHOOTING Substrate Appearance Converter Operation Possible Cause Action Tan or light brown to dark brown substrate. Little amount of gray/white ash Normal back-pressure 0 to 40 o C temperature rise across converter Normal conversion Normal operation None Carbon fouling soft black sooty deposits on substrate. Large amounts of powdery gray/white ash covering the substrate. Dark bronze to black in color Pinholes, burnt substrate foil and/or white powdery appearance efficiencies High back-pressure Low conversion efficiencies High back-pressure Low conversion efficiencies Low conversion efficiencies Clogged air filter Very low cylinder compression Weak ignition voltage Ash originating from sulfated ash content and zinc and phosphorus compounds in the lube oil package Oil fouling. Too much oil entering combustion chamber; possible worn rings or cylinder walls Excessive clearance of valve stem guides Build-up of crank-case pressure Check air filter Check carburetor and ignition system Check rings and valves Chemical wash of catalyst substrate Correct engine to lube oil consumption rate < lb/bhp-hr Use lube oil with < 0.6% sulfated ash content; < 900 ppm zinc and < 400 ppm phosphorus Contact DCL for chemical wash of catalyst substrate Correct engine Contact DCL for chemical wash catalyst substrate Little or no conversion Ignition misfire Correct engine Contact DCL for replacement catalyst substrate Table 7.1 Troubleshooting by Substrate Appearance RC CATALYTIC CONVERTER 20/20

23 8. SPARE PARTS LIST RC3x3 RC4x4 RC5x5 RC6x6 Catalyst R-36-4?K5-?X 368R-36-4?K5-?X A ?Q2-?1 368R-36-4?K5-?1 Catalyst R-36-4?K5-?X - Gasket TBA TBA TBA TBA Wire Mesh X X X X NPT Port X X X X Catalyst part number varies depending on coating and cell density. Contact DCL for full part number. When the catalyst substrates are due for replacement, order the replacement parts as required, use up the spare parts first and stock the fresh parts until the next replacement. Part Number Description Units Recommended quantity to stock A ?Q2-?1 RC catalyst 300 x 300 Ea. 1 full set 368R-56-4?K5-?1 RC catalyst 600 x 300 Ea. 1 full set X Wire Mesh w/adhesive, 0.062"X0.25" FT 18 RC CATALYTIC CONVERTER 21/20