Classes
	Syllabus
1	Intro. to the Course
2	Intro. to Gas and Oil Processing
3	Gas Processing Methods
4	Intro. to Water -Hydrolic Cycle
5	Intro. to Water -Part 2
6	Power Generation/ Cogeneration
7	Electricity Transmission
8	8 Missing
9	9 Missing
10	10Missing
11	Chemical, Reagents,Tools, Rigging
12	12 Missing
13	Land Use and Reclamation
14	Instrumentation and Drawings
	**** Final Exam*****
	Resources
	Staff E-mail

Introduction to Process Technology

Lesson 6

Safety Topic | Power Generation/Cogeneration| Basic Terms

Objectives

1. Introduce Industrial Electricity Use and Generation.

2. Describe Steam Turbine Generator Systems.

3. Describe Turbogenerator Systems.

4. Describe Cogeneration: BTMOSC.

5. Basic Math Continued.

Safety Topic

OSHA's electrical standards address concerns that electricity has long been recognized as a serious workplace hazard, exposing employees to such dangers as electric shock, electrocution, burns fires, and explosions. The OSHA electrical rules help minimize these potential hazards by specifying safety aspects in the dEsign and use of electrical equipment and systems.

The regulations distinguish between "qualified" and "unqualified" persons. Only "qualified" persons can work directly with exposed energized parts. While it may seem that only "qualified" persons would need to be trained to meet the requirements of 29 CFR 1910.332, training is required for any employees who work on, near, or with electrical hazards. The regulation covers all workers who are, or could be, exposed to the hazards of electricity.

Depending on the job, an employee could be considered to be "qualified" for one type of task and "unqualified" for others.

Deenergizing electrical equipment and lockout/tagout

The accidental or unexpected sudden start-up of electrical equipment can cause severe injury or death. Before ANY inspections or repairs are made, the current must be turned off at the switch box and the switch padlocked in the OFF position (lockout). At the same time, the switch or controls of the machine or other equipment being locked out of service must be securely tagged (tagout) to show which equipment or circuits are being worked on.

Maintenance employees should be qualified electricians who have been instructed in lockout procedures. No two locks should be alike; each key should fit only one lock, and only one key should be issued to each maintenance employee. If more than one employee is repairing a piece of equipment, each should lock out the switch with his or her own lock and never permit anyone else to remove it. The maintenance worker should at all times be certain that he or she is not exposing other employees to danger.

Overhead lines

If work is to be performed near overhead power lines, the lines must be deenergized and grounded by the owner or operator of the lines, or other protective measures must be provided before work is started. Protective measures (such as guarding or insulating the lines) must be designed to prevent employees from contacting the lines.

Unqualified employees and mechanical equipment must stay at least 10 feet away from overhead power lines. If the voltage is more than 50,000 volts, the clearance must be increased by 4 inches for each additional 10,000 volts.

When mechanical equipment is being operated near overhead lines, employees standing on the ground may not contact the equipment unless it is located so that the required clearance cannot be violated even at the maximum reach of the equipment.

Personal protective equipment

Employees whose occupations require them to work directly with electricity must use the personal protective equipment required for the jobs they perform. This equipment may consist of rubber insulating gloves, hoods, sleeves, matting, blankets, line hose, and industrial protective helmets.

Tools

To maximize his or her own safety, an employee should always use tools that work properly. Tools must be inspected before use, and those found questionable, removed from service and properly tagged. Tools and other equipment should be regularly maintained. Inadequate maintenance can cause equipment to deteriorate, resulting in an unsafe condition.

Tools that are used by employees to handle energized conductors must be designed and constructed to withstand the voltages and stresses to which they are exposed.

Good Judgement

Perhaps the single most successful defense against electrical accidents is the continuous exercising of good judgement or common sense. All employees should be thoroughly familiar with the safety procedures for their particular jobs. When work is performed on electrical equipment, for example, some basic procedures are:

(1) have equipment deenergized,

(2) ensure that the equipment remains deenergized by using some type of lockout and tag procedure,

(3) use insulating protective equipment, and

(4) keep a safe distance from energized parts.

Employee training

Training requirements for employees working with or around electricity are at 29 CFR ß1910.332óElectrical Training. The training requirements cover:

(1) general requirements (safety-related work practices required by ß1910.331 through 1910.335) that pertain to an employees respective job assignment,

(2) additional requirements for unqualified persons, and

(3) additional training for qualified employees.

Where to go for more information

For general industry 29 CFR 1910, Subpart S Electrical. For constructionó29 CFR 1926, Subpart K Electrical

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Power Generation/Cogeneration

Introduction to Industrial Electricity Use and Generation

Process industries use and commonly generate their own electrical power.

Many industrial sites are remotely located and therefore not on a central power distribution system.

Some industries produce huge amounts of waste heat and it is therefore good practice to harness that heat into electrical power thus increasing profitability.

Power is generated to supply electricity for living quarters, lighting, building heating and ventilation and for use by the electrical motors to run process systems.

Facilities that receive power from a central distribution system such as those near communities may also have back-up power generating capabilities to supplement or provide all their electrical needs in the event of a central distribution system failure. Back-up generators are generally fueled by diesel or natural gas if available.

Smaller plants such as pipeline pump stations produce 480 volts AC three phase power.

Central plants distribute power across a larger area produce voltages on the order of 13,200 volts. These higher voltages are used to reduce the resistive losses of longer lines.

In the plant the major uses of electricity are lighting and electrical motors.

Large power generation equipment types

1 Steam Turbines :Steam turbines use high pressure steam to produce rotational energy which is passed to a generator via an output shaft

2 Gas Turbines: Jet engines or gas turbines are often used in power generation systems to spin a generator.

3 Hydropower :discussed next session .Hydro harnesses the falling power of water to drive a generator. The most common method is a pelton wheel.

Steam Turbines

. Steam turbines use steam pressure to spin a turbine. Steam turbine systems are normally closed systems. None of the steam escapes to atmosphere. The exception to this is geothermal.

The primary function of a boiler is to produce steam at a given pressure and temperature.

To accomplish this, the boiler heats water to high temperatures and pressures.

The pressure-tight construction of a boiler provides a means to absorb the heat and transfer this heat to raise water to a temperature such that the steam produced is of sufficient temperature and quality (moisture content) for steam loads.

In the boiler there is an enclosed space where the fuel combustion takes place. Air is supplied to combine with the fuel, resulting in combustion. The heat of combustion is absorbed by the water in the risers or circulating tubes.

The density difference between hot and cold water is the driving force to circulate the water back to the steam drum.

Note: High pressure and temperature steam is dangerous, step into an invisible leak and it can cause server injury. One way experienced operators find steam leaks is to wave a 1/4 inch wood dowl in the suspected area. They look for the dowel to be cut in half by the steam.

Boiler fuel sources

1 Natural Gas: Natural gas is one of the most widely used fuel sources for boilers due to it's availability, and ability to burn cleanly.

2 Coal:Coal is used often for it's relativly high BTU content, and in the case of some coals, low sulfur content.

3 Waste Heat : Often heat is generated in certain parts of an industrial process that can be recovered and converted from what would be lost heat into electricity.

4 Geothermal :By far the most attractive source due to it's low cost, but it's availibility is limited.

Steam Turbine

The turbine contains nozzles, vanes, and a rotor. It is typically massive and run at the limits of its construction.

Pump

The pump feeds condensed water to the boiler.

Condenser

The condenser cools the low pressure steam exhausted from the turbine. As the low pressure steam is cooled it condenses into low pressure water.

Cooling Water System

The cooling water system is a loop with its own pump and cooling tower.

Generator

The generator is connected to the turbine by a shaft.

Turbogenerators

Jet engines can be combined with a generator to produce a gas turbine generator. The jets typically run on fuel gas but liquid can also be used. Slide 6-6 is a photo of a relatively small turbo generator of 800kw.

The jets operate at a relatively high speed. 50,000 rpm is not uncommon

The jets output shaft is connected to a gearbox which reduces the shaft speed to the generator itself, typically to 1800 RPM.

Turbogenerator sets lend themselves to cogeneration discussed below.

Turbogenerators provide a wide range of power from 800kw sets to 450mw sets.

A gas turbine system is far simpler than a steam boiler system.

• no water is required, therefore no water system is required
• systems are relatively lightweight
• no boiler required meaning much less maintenance
• freezing is not a concern
• the system is quick starting, a gas turbine can go from shutdown to fully loaded in 4 minutes

How a jet engine works

As the common shaft of the generator turns air is sucked into the compressor where several rows of blades compress the air. As the air moves from left to right the volume of the air is reduced as the pressure is increased. This air then enters the burner can where liquid or gas fuel is injected via a fuel nozzle and ignited. Burning of the fuel turns low volume hi pressure air into high volume high pressure air. This air is then applied to the power turbine section of the jet where it turns the power blades and exits the exhaust.

Cogeneration

Cogeneration is used to capture exhaust heat which would otherwise be wasted. Many industries produce "waste heat". Of course this heat represents energy that may be captured and put to use.

The normal thermal efficiency of a coal fired power plant is about 30%, with cogeneration the efficiency can go as high as 47%. This is a significant amount of additional electricity from the same amount of fuel

The gas-steam turbine, combined cycle consists of three basic components;

• gas-turbine generator set,
• waste-heat recovery boiler, and
• a steam turbine-generator set.

The gas turbine's exhaust gas is passed through the waste-heat recovery boiler where steam is created. Steam from the waste-heat recovery boiler is then sent to a steam turbine which drives an electric generator.

Basic Terms of Maintenance, Operations and System Components

Axial Axial flow in a jet engine is flow along the primary axis or spindle of the jet, some jets use centrifugal flow in their compressor section

Boiler a device in which heat changes water into steam.

Burner can In a jet engine, the chamber (approximately shaped like a can) in which fuel and air are mixed and ignited

Central distribution system Specifically at Prudhoe Bay, a large facility which produces electricity for the majority of the field

Cogeneration Technology designed to capture the waste heat from a primary industrial process

Compressor In a jet engine the section which compresses the feed air just before it enters the burner can

Gas Turbine A jet engine

Generator A machine which produces electrical power, in common use the power is 3 phase alternating current.

Geothermal Power from the heat of the earth, typically by using underground steam reservoirs

Hydropower Power produced by the force of falling water

Nozzle In a jet engine, the component of the fuel system which sprays fuel into the burner can Rotor The rotating part of any machine as a jet, turbine, or generator

RPM Revolutions per minute

Stator The non rotating gas guiding part of a machine.

Steam Water in the gaseous state

Thermal efficiency In power generation, the amount of energy in a fuel which is put to useful work.

Turbine A bladed rotor which spins under influence of a high pressure gas such as steam or the blast from a burner can

Turbogenerator A jet engine/generator combination designed to produce electricity

Waste heat Heat exhausted from an industrial process or plant. The primary source of energy for cogeneration.

Lesson 6 Task/ Quiz

Go to the basic math link and study pages 38 thru 47. Lesson 6 Quiz will contain questions on this material.