Portlands Energy Centre

As part of Doors Open Toronto, I toured the Portlands Energy Centre. They produce electricity by two processes. First, they combust the natural gas, which turns gas turbines. Second they capture the heat from the combustion and use it produce steam, which then turn steam turbines. The gas turbines and steam turbine produce the actual electricity. They use Lake Ontario water as cooling water, but here is what I find interesting. They need ultra pure water to use in the equipment for cooling, so they have a multi step process to clean the water, including filtration, disinfection, reverse osmosis, and ion exchange. When that cooling water is later released to Lake Ontario, after being properly cooled, it is actually cleaner then when they pumped it into the plant. I followed the maze of pipes wondering how they ever find the right one when they need to do maintenance, and I desperately a process flow diagram, so I could follow everything along. When standing in the room with several pumps for the cooling water, the room was actually vibrating from the pump motion. Then of course, I started to wonder about the structural engineering and the amount of motion the structure has to be able to bear. Things an engineer thinks about, even when on vacation.

I took lots of photos because I find a beauty in the maze of pipes. It’s probably the chemical engineer in me. Some were labeled, so were not. Almost all were silver. This must make for a fun time when you need to pipe a specific pipe. However, there is a simple elegance, and please excuse me, but beauty in the pipes going everywhere, one next to another and a top another, in an orderly fashion. It is a maze but a logical maze. No mess. Just order.IMG_6972 IMG_6980 IMG_6989 IMG_6991 IMG_6997 IMG_6998 IMG_7007 IMG_7009 IMG_7018

Huge pipe of cooling water

Huge pipe of cooling water

Ion exchange columns

Ion exchange columns

One of the pumps so powerful it made the room vibrate

One of the pumps so powerful it made the room vibrate

Reverse osmosis step

Reverse osmosis step

Waste to Energy Plant

Last week I got the chance to tour a waste to energy plant. The plant receives non-hazardous, household garbage from municipalities, consumer businesses, government agencies, and international ports. It burns the waste and converts the energy given off during the burning to electricity, which is then put into the power grid. Some of the waste that comes from government agencies need secure destruction, and at the plant, the waste is put directly into the feed stream and burned, so as to allow the needed secure destruction. The waste from international ports, such as nearby airports, must be burned to prevent any pathogens entering the country that may affect agriculture, and so it also is fed directly to the feed stream. Interestingly, the municipalities that send waste to the plant discourage their residents from putting yard waste into the trash. Besides being environmentally unfriendly because yard waste can be composted and nutrients returned to the earth, the yard waste is also not good for the waste to energy process because it produces nitrogen oxides (NOx), which forces the plant to put in more pollution control.

There are 88 waste to energy plants in the US, and 45-46 are Covanta’s, the owner and operator of this plant that I toured. The plant receives about 1000 tons garbage/day and after burning it, produces about 300 tons ash/day, which is 10-15% fly ash and the rest bottom ash. Thus, the plant achieves about a 70% weight reduction and also a 90% volume reduction. The fly ash is sent to monofill, which is like a landfill but only accepts fly ash. Fly ash can be used in making concrete, so evidently there is currently research being done by both the concrete industry and various waste to energy plants as to if this fly ash can be used for concrete and thus also be reused.

With the exception of the trash that has to go directly into the feed, when it first comes to the plant, the trash is placed on floor where humans look at trash to remove anything that should not be going into the boiler. For example, inert material shouldn’t go into the boiler because not only does it not burn, it is also a heat sink and reduces the efficiency of the process. The trash is then put into a storage pile to be eventually fed into the boiler feed. A large claw moves the trash to piles, mixes the piles, and then moves trash from the piles into the boiler feed.

Pile of trash waiting to be burned

Pile of trash waiting to be burned

Large claw picks up trash to put into feed

Large claw picks up trash to put into feed

Trash slides into the entrance to the boiler

Trash slides into the entrance to the boiler

The trash is sent to one of three boilers, each of which has six cells. The boilers burn the trash at 1800-2000°F (1300K). The boilers are initially heated up with diesel fuel, but then the trash sustains the burn. However everyday diesel fuel is used to test the burn.

The boilers

The boilers

View through a boiler's window of the trash burning

View through a boiler’s window of the trash burning

Pipes and ducts everywhere

Pipes and ducts everywhere

The heat from the boilers is used to heat water to turn it into steam. The water is in a closed loop system, but they use about 20-25,000 gallons of water per day due to loss. [They use another 200,000 gallons/day for the cooling tower and are exploring with the nearby wastewater treatment plant using treated wastewater for this.] The water goes through a reverse osmosis treatment for purity, so nothing damages the turbines and the rest of the system. The produced steam is superheated but drops to 700°F before entering the turbines. There are two turbines with 14 stages. The steam turns the turbines, and that motion is converted into electricity in the generator. They produce 14.5 MW per turbine. Because of the work the steam does on the turbine, the steam enters the turbine at 600 psi and leaves in vacuum in a 10 ft length.

The turbine (gray and blue) and the generator (red and white stripes)

The turbine (gray and blue) and the generator (red and white stripes)

All the gases that leave the boiler pass through a series of air pollution control units. Ammonia, lime slurry, and carbon are used for pollution control. There are probes in the system to sample flue gas for pollution control additives that are needed. The treated gas then goes to a baghouse where particulates are captured. The air is below 300°F before going into baghouse, so it has cooled quite a bit.

The ash from the boiler is sent through a unit to remove all metals. The ferrous metals (attracted to magnets) are separated from the rest of the metals, and all the metals are sold for scrap.

bottom ash

Bottom ash entering the separator

Metal that has been separated

Metal that has been separated

The whole process is monitored in a control room by one or two people. I was amazed at how simple the process was. I, the environmental engineer, was of course geeking out at the whole thing, but it was a really cool process and efficiently run.

Control panel monitors

Control panel monitors

Finally here is a very short video of a few scenes from the plant. This includes waste being loaded into the feed, the fire in the boiler, and bottom ash entering the metals separator.

Blue Lagoon

Day 1 in Iceland. I think I got about 20 minutes sleep on the plane. We drove to the western edge of the Reykjanes Peninsula to see the lighthouses in Garður. Then it was on to Iceland’s most visited tourist attraction the Blue Lagoon. Some genius turned what was a pool formed by wastewater from a geothermal power plant into a rather expensive, somewhat posh hot pot to which all tourists flock. It is really cool though. The water color is this gorgeous, cloudy sky blue. Also, they give excellent massages while you lay on a float in the lagoon. When you’ve been on a plane for six hours with no sleep, walking around a wonderfully heated pool and then getting a massage is quite frankly, a great cure for your exhaustion. Walking around the lagoon is great exfoliation for your feet, and they have buckets of silica from the lagoon to rub on your face for a facial. From a geology standpoint, the pool is really neat because you can walk through micro heat spots, not to mention to entire heated by geothermal heat thing. In some areas the pool is warm and in some areas, the pool is hot. The lagoon was also a great place for me to play with my new GoPro camera, which can be used underwater.

The area around the lagoon is bizarrely pretty. It is dark craggily, sharp volcanic rock that is covered with this lush, soft in appearance, green plant. I am guess the green is actually lichen or a moss, but I need someone to educate me on what it actually it.

Power plant which caused the Blue Lagoon to form

Power plant which caused the Blue Lagoon to form

Blue Lagoon

Blue Lagoon

Bridge over Blue Lagoon

Bridge over Blue Lagoon

I'd be curious to know if this bridge is ever not slippery

I’d be curious to know if this bridge is ever not slippery

Not often you see a lifeguard dressed like that

Not often you see a lifeguard dressed like that

Rock edge of Blue Lagoon

Rock edge of Blue Lagoon

Precipitate on rocks

Precipitate on rocks

Surrounding terrain

Surrounding terrain

Lichen? Moss? It covers the volcanic rock

Lichen? Moss? It covers the volcanic rock

Solar Impulse

Solar Impulse, the solar powered plane that can store enough energy to fly through the night, is currently at Udvar-Hazy Center. The plane is a marvel of engineering both from the standpoint of being able to collect enough solar energy during the day to power itself all day and through the following night but also from the standpoint of being light enough in weight that it needs very little energy to keep it flying. I went to see it while it was open for public viewing Saturday, and from an engineering perspective, it is just beautiful. When viewed in person, you can see how the plane is covered in high strength fabric. In the back stabilizer, you can see the internal structures that give the stabilizer its shape. It is just an amazing vehicle. Note: If you click on any of the photos, it will open up larger in a new page to allow a better look.

front panorama of Solar Impulse

front panorama of Solar Impulse

Side panorama of Solar Impulse

Side panorama of Solar Impulse

Solar Impulse cockpit and middle two propellors

Solar Impulse cockpit and middle two propellors

view down the wing span

view down the wing span

Tail and stabilizer

Tail and stabilizer

View of stabilizer from side showing internal support

View of stabilizer from side showing internal support

View from below stabilizer showing internal supports and photovoltaic cells above

View from below stabilizer showing internal supports and photovoltaic cells above

Solar Impulse wing flaps with photovoltaic cells on top

Solar Impulse wing flaps with photovoltaic cells on top

View between wing flaps using my zoom lens to show wires connecting photovoltaic cells

View between wing flaps using my zoom lens to show wires connecting photovoltaic cells