Fuel Cells and a Sad Goodbye

Fuel Cells and a Sad Goodbye

Like many of you, I”m in a rather depressed state after not only

paying Uncle Sam his due, but also watching my accumulated

wealth take a nosedive in that horrific market plunge. Although

last week”s column on lunch with The Donald probably seemed

light-hearted, my mood the past month has actually been quite

somber. The reason for this sadness was the sudden and shocking

death of a good colleague and friend, Charles Grun.

On March 13, Charlie completed his usual morning run of several

miles at a local track, got in his car to return home and had a fatal

heart attack. Although a diabetic, Charlie was Mr. Physical

Fitness and, in addition to running, regularly engaged in racquet

ball games with one of our graduate students some 40 years

younger. Not too long ago, grounded by a knee problem, Charlie

underwent surgery and was back in his running shoes in a

remarkably short order. Next to my wife, it was Charlie who for

years has kept prodding me to keep up my daily three-mile walks.

A voracious reader, he also passed along to me his many technical

magazines, sources of many tidbits I”ve used in these columns.

My last contact with Charlie was in February, when he called me

in Marco Island to ask if I needed reading material and to make

sure that I was walking. I had plenty to read and could report a

walk of over six miles on the beach that morning.

In spite of, or perhaps because of his horrible childhood, Charlie

was the most positive individual I”ve ever known. At 10-12 years

old, he was in a line with his parents when they were separated,

Charlie to work in the concentration camps while his parents

presumably perished in the gas chambers. Possibly because of his

surviving the Holocaust, Charlie woke up every morning thinking

it”s great to be alive and filled his day to the fullest with work,

exercise, a thirst for knowledge and family. I had not met his

family until the day of the funeral and was in for a surprise.

Charlie had spoken on occasion about his sons and daughters. I

found that he actually had only daughters and that his “sons” were

really sons-in-law, but were treated by Charlie as his own. This

was my first Jewish funeral service, held the next morning after

his death. I”ve been to services at which the deceased was

extolled to such an extent that you wondered whether this saint

was the person you had known. In Charlie”s case, we all agreed

that every heartfelt word spoken in praise of his virtues was

absolutely true.

Before joining our battery group, Charlie had his own little

company making electrodes for metal-air batteries and fuel cells.

It”s fitting that this week”s column should deal with fuel cells.

Today”s gasoline prices have spurred renewed interest in battery-

powered vehicles. Honda and Toyota have been selling in Japan

“hybrid” vehicles powered by combining the battery and internal

combustion engine. Last year, DaimlerChrysler demonstrated its

NECAR 4 auto, powered by a fuel cell. Also, there are buses in

the U.S. and Canada that are running on fuel cells.

What is a fuel cell? In a battery, the amount of electricity we get

out depends on the amounts of active ingredients packed in the

electrodes and, possibly, in the electrolyte of the battery. In a fuel

cell, we also have electrodes and an electrolyte. However,

instead of packaging our active ingredients, we keep feeding these

ingredients into the fuel cell as it”s generating electricity. So, as

long as we keep feeding it, the fuel cell continues to make

electricity. At the same time, so as not to clog up our fuel cell,

we must remove the products of the cell reaction.

What do we feed it? It sounds tricky, especially since the

products of most reactions that occur in practical batteries are

solids. One can imagine having to continuously shovel out this

stuff to make way for the incoming fuel. But suppose we feed the

two electrodes with simply hydrogen and oxygen gases? If you”ve

taken high school chemistry, you”re right. It is just the reverse of

the electrolysis of water. In that experiment, we hooked a battery

to a couple of wires, stuck the wires in water with some acid, and

collected hydrogen and oxygen in our test tubes. And what is the

product in our fuel cell? Of course, it”s the environmentally

“greenest” possible material – water! We don”t even have to

supply pure oxygen, but can just use a fan to blow in air. Oh, by

the way, the other product is electricity.

If we don”t happen to have hydrogen handy, we can “reform”

something like natural gas into a hydrogen-rich feedstock for our

fuel cell. In the greenest of all possible worlds, we might even

use solar energy to generate hydrogen by electrolysis of water.

It sounds like Utopia, doesn”t it? There are a couple things I

didn”t mention. One is that the hydrogen and oxygen don”t just flit

into the fuel cell and neatly react to form water. We need a

catalyst on the electrode surfaces to help them do the right thing.

A catalyst provides a surface that encourages, for example, a

hydrogen molecule to split into two hydrogen atoms. You

remember that a hydrogen atom is just an electron whirling

around a proton. The catalyst may then prod the hydrogen atom

to give up its electron to the electrode, leaving a proton, which is

a hydrogen ion. The hydrogen ion then can travel through the

electrolyte carrying its positive charge, while the electron with its

negative charge goes through the electrode to the outside world

as electricity. The reactions involved in different types of fuel

cells are different but you get the idea. The surface of an ideal

catalyst is unchanged by the whole process and is ready to do the

same for the next hydrogen molecule. Unfortunately, it turns out

that platinum is the best catalyst. As you know if you”ve priced

platinum jewelry, it isn”t cheap! Cost is a problem.

There are a couple more small items. In order to generate the

rather large currents needed to drive a car or generate power for

a building, you need lots of ions in the electrolyte. It also helps

to speed things along by raising the temperature. Now things get

a little dicey. For decades, the fuel cells used on space missions

(e.g., on Apollo 13) have contained strong, corrosive alkaline

electrolytes of potassium hydroxide, almost pure lye. These

alkaline fuel cells operate at roughly 200 degrees Centigrade, well

above the boiling point of water (100 degrees Centigrade).

The alkaline fuel cells seem on their way out. A United

Technologies subsidiary, ONSI, is marketing another type of fuel

cell for larger scale power generation. Instead of an alkaline

electrolyte, this fuel cell employs a phosphoric acid electrolyte,

operates at about the same temperature and uses reformed natural

gas. ONSI has sold over 200 of its 200-250 kilowatt fuel cell

plants worldwide. (For comparison, our home”s electricity

consumption is about 25 kilowatt-hours per day. If my math is

correct, one of these ONSI plants could handle the needs of

roughly 240 such homes.) The niche for these phosphoric acid

fuel cell plants is “distributed power”, a buzzword for having your

own on-site (hence, ONSI) power generator. Banks, hospitals,

airline terminals and the like are fuel cell customers worried about

computer glitches and power for emergency situations.

“Cogeneration” is another term you”ll see in connection with fuel

cells. Not only do they operate at high temperatures but the fuel

cells themselves generate a lot of heat. Part of the heat can be fed

back to keep the fuel cell hot. The remainder of the heat can be

used to either heat buildings or to drive motor generators that in

turn generate more electricity. The high temperature also

vaporizes the water produced, making its removal a cinch.

The DaimlerChrysler NECAR 4 employed yet another kind of

fuel cell called a proton exchange membrane fuel cell. This fancy

sounding name means that the electrolyte is not a liquid at all.

Instead, a special polymer membrane is used that allows hydrogen

ions (protons) to scoot through it and carry the current. This

polymer membrane fuel cell can operate at much more reasonable

temperatures, even low enough that it is being considered as a

possible replacement for lithium batteries in laptop computers.

Again, platinum is the catalyst.

There are two other types of fuel cell that do not use platinum but

neither of these fuel cells will be used in your laptop computer.

They literally operate red hot, at temperatures between 600 to

1000 degrees Centigrade. You may also have read press

accounts about fuel cells using either methanol or gasoline

directly. These ideas are being pursued quite vigorously.

Finally, Charlie, I miss you greatly. Yes, I have plenty to read,

including that foot-high stack of magazines you left me. And yes,

stop bugging me; I walked four miles this morning. And, dear

readers, I leave you with a word spoken by Charlie”s courageous

wife at his service. After her own tribute to her husband, she

made us all smile with her parting admonition – “Exercise!”

Allen F. Bortrum