La vida en contexto urbano

A. General

1. Boiler equipment room 2. Pump equipment room B. Chemical

1. Boiler equipment room 2. Pump equipment room C. Electrical

1. Boiler equipment room 2. Pump equipment room D. Gas, oil, and air

1. Boiler equipment room II. Preventive Maintenance

A. Boiler 1. Internal 2. External B. Controls

1. Electrical 2. Mechanical C. Steam appliances

1. Safety relief valves 2. Blowdown valves 3. Isolation valves

III. Boiler Operation

a. Pilot check (gas and oil) b. Main flame check (gas and oil) 2. Run cycle

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VI. Daily, Monthly, and Yearly Inspections A. Daily inspections

D. Yearly inspections

1. Open, clean and close fireside 2. Open waterside

A. What and when to replace 1. Bi-annually

2. Yearly

1. Safety

a. General Safety. As we are all aware, being operators and maintainers of equipment, it is to everyone’s benefit to be safety conscious. Your company should have a safety policy, or safety guidelines to follow. Some of the things that we want to be aware of are the common things we may forget from time to time.

We should make a habit of wearing safety glasses or safety goggles where required; ear plugs where required (OSHA guidelines and/or decibel testing);

safety shoes, boots, or safety rubber boots; long-sleeved shirts and long pants;

also rubber gloves when required. Kidney belts are also required by OSHA or company guidelines when lifting by hand. There may also be a weight limit for lifting objects by hand. Check with you safety engineer or supervisor if you are not sure. Hard hats or bump hats may also be required headgear.

When entering the boiler room or mechanical area, pay attention to all safety warning signs. These may include ‘‘Hearing Protection Required,’’ ‘‘Hard Hat Area,’’ ‘‘Safety Glasses Required,’’ or others. Be on the lookout for safety or warning signs that say ‘‘No Smoking in this Area,’’ ‘‘High Voltage,’’ ‘‘Chemi-cals,’’ ‘‘Flammable Liquids,’’ ‘‘Gases,’’ or others.

You should be aware of your surroundings in the mechanical room. Use your senses. You want to look, hear, and smell. A steam leak can be a cause of severe burn or even death. You never know when water, oil, or a chemical has either been spilled or has leaked out of a container. Gas leaks are not always

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easy to find. Natural gas leaks can cause explosions and fires, which can cause serious injury or death.

b. Chemical Safety. Chemicals in the mechanical or boiler room areas are necessary because of the need for water treatment, descaling, solvents for oils, and so on. One of the first things you should know about chemicals is the labeling of the chemical and what the labeling means. Become familiar with and read all labeled chemicals and materials for ‘‘Warnings.’’ All chemicals are required to have information (minimum) listing the following: ingredients, haz-ards, first aid and disposal procedures. Material safety data sheet (MSDS) infor-mation should also be posted in an area accessible to personnel for their review.

If you are unsure of a chemical, do not use or open it until you know what you are dealing with. You should have protective equipment such as goggles, face shield, rubber gloves, rubber apron, rubber shoes, and mask. Some chemicals may not be toxic but may be CORROSIVE. If you do not know what a chemical or liquid is, do not mess with it. (Use common sense) until you can determine what it is and take the necessary precautions for use, removal, clean up, or dis-posal. Keep all empty containers stored in their designated places. Keep all con-tainers tightly closed and covered and properly labeled. Do not change concon-tainers without proper labeling.

If chemicals and chemical equipment are supplied and maintained by a

‘‘Chemical Company,’’ make sure they supply all required information on the equipment and chemicals even though they may be maintaining the equipment and chemical for you. (See discussion in Section VI). When using spray cleaners and chemicals, do not use around electrical equipment. Do not discard chemicals down drains. Always follow EPA guidelines for removal and disposal of chemi-cals. (Ask trainees for questions on chemical safety before continuing.)

c. Electrical Safety. Electrical safety in the boiler and mechanical areas is essential. Caution and common sense around electricity should always be ob-served. Untrained personnel should be oriented and trained before any introduc-tion to electrical components. We as professional maintainers and operators should be constantly aware of the dangers and possible hazards of electrical equipment. Wiring that has been wet can cause short circuits, major malfunctions, explosions, severe injury, and even death. (Illustrate lax electrical safety, use a story about electrical hazards to drive home the point or near miss of injury).

Any person can become lax about electrical safety. Most people are aware that high voltage is very dangerous, but forget about everyday electrical current, such as 110/120-V electricity. Even 24 V electricity can be deadly.

When working on electrical appliances or trouble-shooting electrical con-trols always use proper tools and properly insulated tools and protective clothing, such as rubber-soled footwear and gloves. Make sure all equipment is shutdown and all circuits are disconnected (or fuses pulled) before working on the

equip-ment. Lock and tag-out all equipequip-ment. If using a team or buddy system, do not assume anything or take your team member for granted. Any one can make an error and a small error can be deadly. The main thing is to ‘‘work and be safe.’’

(Relate another story about buddy or team safety.) Ask for questions before continuing.

d. Gas, Oil, and Air. When we talk about gas such as ‘‘natural gas,’’ we do not pay too much attention because it is in our everyday lives and hardly ever dealt with. It remains inside piping and well hidden from exposure to us. The fact is, gas (natural gas) is colorless and odorless and very deadly. Natural gas will not ignite normally unless it is introduced to air or oxygen and ignition or a spark from a source. This is where we get the term ‘‘combustion.’’ For our discussions on combustion and gas, combustion can be very dangerous unless properly controlled. We are concerned with uncontrolled combustion.

When operating, maintaining, or trouble-shooting a boiler with gas or oil fuel, always look for leaking valves and fittings, and for proper boiler firing.

Check for proper pressures, and if leaks are found in gas, oil, or air lines, properly locate and mark the leaks. If necessary or required, shutdown the equipment as soon as possible or practical and make repairs or notify the proper personnel to make the repair(s). Oil such as No. 2 fuel oil can also be hazardous, even lying on the floor. Clean all fuel oil and oil spills, repair the source of the leak as soon as possible or practical. Use absorbent for clean up and removal of spilled oil and discard according to EPA and OSHA requirements. Large fuel oil spills should be dealt with immediately, as fuel oil is highly volatile. Compressed air can be dan-gerous also. Introduced to a fuel source helps complete the combustion. It would only need a spark to cause ignition of some kind. One of the most common dangers of compressed air is using it to blow out or clean equipment. Your eyes are the most likely target of a propelled particle. Always use proper safety equip-ment when using compressed air and approved air too. Make a practice of not using modified air tools.

(Use story or personal experience with any gas, oil or compressed air hazard for an example of safety)

Ask question of class before continuing.

Movie: Safety in the work place.

2. Preventive Maintenance

a. Boiler. When discussing preventative maintenance on the boiler and mechanical room equipment, we want to do our best to keep the equipment run-ning and avoid nuisance shutdowns or even major breakdowns. Boiler owners and operators have been striving for years to reduce costs of major rebuilding, replacement, and equipment repairs. We will discuss measures to help assure long-term operation with minimum cost.

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Waterside. On the boiler ‘‘waterside,’’ after shutdown and isolation of the boiler, let the unit cool from steaming temperature to below 200°F before draining of the boiler. This needs to be done naturally and not by means of in-duced air or cold water. Use of either inin-duced air or cold water to reduce boiler temperature, can cause boiler and refractory damage and lead to major repairs for tube shrinkage or undue metal stress. Let the boiler cool to 140°F or lower before removing hand-hole or manway covers. OSHA standards and require-ments for ‘‘personnel protection’’ are greater than 140°F. Remove all plugs on the water column(s) and low-water cutout piping and tees. Flush out with water to remove debris. Also remove the low-water cutout control head and flush with water to remove debris from the bowl or cavity. If any sludge or scale buildup is evident, scrape and flush out. Make sure to flush the drain piping on the water-side of the boiler. Flush, using high-pressure water. Remove all debris by scraping and flushing. If feedwater chemical treatment is working well, you should have soft sludge in the bottom of the mud drum on waterwall boilers and the bottom of the steam drum on firetube boilers. Make sure that the bottom blowdown opening is flushed and clear of debris. Special areas of attention on firetube boilers are the rear tubesheet and tube-to-tubesheet connections, tubesheet-to-fire tube area, fire tubes, boiler shell, and shell bottom. Also the water feed inlet baffle.

Note: during this procedure the chemical representative should be there to observe and gather samples of the sludge, or other debris. This will give the representative a hands-on look at the boiler internals and will be important in future water treatment recommendations to you.

Fireside. After completing the internal waterside of the boiler, attention is turned to the fireside of the boiler. Open inspection doors (for firetube boilers, front and rear doors) for visual inspection and debris removal. You may encounter soot, red dust, scale, or dry chemical residue. If any of these residues are present, your boiler service representative should be called in to see the problem and fix it.

Example. Firetube boiler. If soot is present (if the firetubes have turbula-tors, remove them), brush out the firetubes and tubesheets (fireside) removing the soot. The burner then needs to be adjusted before returning to full service.

If red dust is present, this means there may be a problem with fireside condensa-tion. If scale or chemical residue is present, you may have leaking tube joints.

In all these cases, your boiler service professional should be called in to identify and fix the problem. Complete the fireside inspection by visually inspecting the boiler tubes, tubesheets, furnace tube (Morrison tube) for damage or leaking areas and make any repairs needed. The burner cone refractory and refractory on the front and rear doors (refractory in the furnace) should be inspected and patch coated or replaced as needed. The jurisdiction inspector will note any repairs or replacement necessary to return the boiler back to good condition and return to service.

b. Controls. On the controls, remove waterside probes (such as LWCO Warrick probes) and inspect, clean, and reinstall or replace if necessary. Inspect all electromechanical controls for ruptured bellows (seals) and bare or frayed wiring, repair as necessary and replace their covers. Check all linkages, oil levels, and switches, where practical, for excessive wear or loose fittings and repair or replace as required. Remove and clean flame scanner or rectifier and reinstall.

Check the packing on all valve stems and repair or replace as needed.

c. Appendages. Check all appendages such as safety relief valves (pull levers to check for frozen seats, and if valve seat is frozen, replace the valve).

Check all blowdown valves, check shaft packing and replace if required. A large amount of the foregoing section should be taught by ‘‘hands-on.’’ Use spare valves or illustrations, cut-aways or diagrams. Using an actual boiler, while out of service, is the best.

3. Boiler Operation

To begin, you need a standardized start-up, operation and shutdown check list available for each boiler and its related equipment.

Sample Piping

——— Check that all valves are oriented in the proper flow direction.

——— Check linkages on all regulating devices, valves, and dampers.

——— Check that all metering devices have been replaced in accordance with recommendations.

——— Check all piping for leakage during the field hydrostatic test.

——— Check with owner’s water treatment consultant to assure that feed-water and chemical feed piping arrangements are satisfactory.

——— Check that all flange bolting has been torqued to proper levels.

Vent and drain piping

——— Check all the drain and vent lines for obstructions or debris.

——— Check that all drain and vent lines terminate away from platforms and walkways.

Water columns

——— Check all connecting piping joints for leakage.

——— Check all safety and alarm system wiring.

——— Check isolation valves to be sure they are locked open.

Safety valves

——— Check for blockage on the outlet.

——— Check that all vent pipe supports have been installed in accordance with recommendations.

——— Verify all valves for manufacturer’s settings (set pressures are shown on valve tag).

——— Verify that gags have been removed from all valves.

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Others

——— Check proper alignment on all ducting and expansion joints.

——— Check all sliding pad installations to ensure proper movement.

——— Check that all normal service gaskets have been installed and have been properly torqued.

Summary of Valve Positions

Valve Shutdown Hydro Boil-out Start-Up Operating

——— Steam shutoff Close Close Close Open Open

——— Steam stop/check Close Close Close Open Open

——— Drum vent Close Close Close Open Open

——— Feedwater control Close Close Close Close Open

——— Feedwater control Close Close Close Close Open

isolation valve

——— Intermittent blow down Close Close Intermittent Close Intermittent

——— Chemical feed Close Close Close/open Close Open

——— Water column drain Close Close Close Close Close

——— Water gauge drain Close Close Close Close Close

——— Safety valve Free Gag Free Free Free

——— Steam gauge shutoff Open Close Open Open Open

The summary of valve positions are basic and standard for most boilers.

The concern here is to have a checklist for start-up and operation.

The summary of valve positions includes positions for shutdown and lock-out when boiler is to be shut down for scheduled or nonscheduled work.

Line up your valves per the ‘‘summary of valve position.’’ The drum vent is left open until you achieve approximately 5 psig steam. This drives out the oxygen from the boiler and water and helps prevent oxygen corrosion. Make sure all water makeup valves at the boiler, return and deaerator system are in open position. Also make sure you have water to the boiler feed pumps before starting the pumps. If you run the boiler feed pumps dry, it will more than likely mean expensive pump repairs. Do not dry run the boiler feed water pumps.

Line up the gas valves or oil valves to the burner. Check fuel oil level supply before starting. Check the fuel oil pump and make sure this pump does not dry start as it may cause expensive repairs. Check the air and oil filters and clean or replace them as needed. Check all electrical resets (i.e., BMS Control, High Limit, Air Switch, GP Switches, etc.).

Before starting the boiler, let us make one more trip around the unit to make sure everything is in place and we did not forget something. Check the boiler water level, water level gauge glass cocks, fireside door or furnace access bolts and nuts, and fire chamber sight glass. If any of these items are in need of repair, or glass is cracked, repair or replace before starting the unit.

b. Start-up. Push the RESET button on the boiler management system (BMS), set the firing rate control to manual, and set the rate on ‘‘0’’ or ‘‘mini-mum’’ position, turn the boiler control switch to ON. Switch the BMS RUN/

CHECK switch to CHECK when the pilot/ignition starts. This allows the BMS to stay in ignition mode until you can check the pilot flame and scanner signal (or if initial start-up, perform pilot turndown test). Visually check the pilot to see if the flame is steady or separating from the pilot assembly. No separation should be seen. Note. The pilot flame should rotate approximately one-third the way around the burner face, although it is permissible to be as short as 6–8 in.

The pilot pressure should be set per ‘‘factory recommendations.’’ Now move the RUN/CHECK switch to run to start the main flame.

On dual-fuel burners make sure, if gas is the primary fuel, that calibration of the burner on gas is performed first, then set and calibrate on fuel oil. We will assume at this time that all calibrations of fuel and air ratio are correct. This will be discussed under ‘‘calibration.’’

Now that we have established the main flame and we have noted that the flame is stable, the boiler needs to warm up. Leave the boiler on low or minimum fire until all refractory is dried out and hot. On steam boilers, warm the boiler until you have reached approximately 5-psig steam pressure. Close the steam drum vent valve. Most of the oxygen will have been removed from the boiler water by this time. This will help assure that no oxygen corrosion takes place.

Recheck all pressure and temperature gauges, boiler water level, and makeup or return tank levels. Now the boiler can be manually fired or ramped up to about 50% firing rate. Take a moderate amount of time to accomplish the manual ramp up. This will allow moisture and condensation to be removed from the fire cham-ber and stack. This process can take as little as 4 hr or as much as 24 hr, depending on type of boiler and amount of refractory.

c. Normal Operation. While the unit(s) are operating under normal con-ditions, we want to maintain operational checks. These should include (but not be limited to)

1. Steam pressure and tempera- Is boiler maintaining designed

ture steam pressure and temperature

under all load conditions?

2. Modulating control of boiler Are boiler controls following steam demand promptly and accurately? Are set points cor-rect?

3. Is boiler going to ‘‘low fire’’ Under low-load conditions, is

properly? boiler cycling (or shutting

down) at proper pressure/set-point?

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4. Do any of the setpoints change slightly each time the boiler cycles?

This is information that is vital to correct boiler operation, and should be monitored regularly. Also, check the water level in the boiler sight glass for stability. Check for rapid fluctuation in the steam drum water level. The sight

This is information that is vital to correct boiler operation, and should be monitored regularly. Also, check the water level in the boiler sight glass for stability. Check for rapid fluctuation in the steam drum water level. The sight

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