Some background: Kenneth Aldred Spencer (January 25, 1902 – February 19, 1960) was a Kansas coal mine owner who transformed a government surplus factory into the world's biggest ammonium nitrate producer. Money from his and his wife's estate was donated to philanthropies throughout Kansas. As a trained geologist and engineer Spencer patented processes for extracting by-products from coal which led to the establishment of the Mineral Products Company of Pittsburg. In 1941, the War Department contacted him about operating a weapons-grade ammonia nitrate plant near Crestline, Kansas that would become the Jayhawk Ordnance Works. He set up the Military Chemical Works, Inc. as a subsidiary of Pittsburg & Midway with himself as president and built the plant by 1943 with it producing 14,500 tons a month.
After the war with help from J.H. Whitney & Company he entered into a lease with an option to buy (which he did in 1951) the plant to use the ammonia nitrate as fertilizer under the new name of Spencer Chemical. He succeeded his father as head of the Pittsburg & Midway. It was so successful that he was able to endow a foundation by 1949. Spencer would also buy plants in Calumet City, Illinois; Henderson, Kentucky; Vicksburg, Mississippi; Fort Worth, Texas and Orange, Texas. When Kenneth Spencer died in 1960, his wife, Helen, liquidated the companies by selling Spencer to Gulf Oil. The Spencer Chemical Corporation name disappeared following its purchase by the Pittsburg and Midway Company.
Ammonium nitrate is a chemical compound, the nitrate salt of the ammonium cation. It has the chemical formula NH 4NO 3, simplified to N2H4O3. It is a white crystalline solid and is highly soluble in water. It is predominantly used in agriculture as a high-nitrogen fertilizer. Its other major use is as a component of explosive mixtures used in mining, quarrying, and civil construction. It is the major constituent of ANFO, a popular industrial explosive which accounts for 80% of explosives used in North America.
The industrial production of ammonium nitrate entails the acid-base reaction of ammonia with nitric acid:
HNO3 + NH3 → NH4NO3
Ammonia is used in its anhydrous form (i.e., gas form) and the nitric acid is concentrated. This reaction is violent owing to its highly exothermic nature. After the solution is formed, typically at about 83% concentration, the excess water is evaporated to an ammonium nitrate (AN) content of 95% to 99.9% concentration (AN melt), depending on grade. The AN melt is then made into "prills" or small beads in a spray tower, or into granules by spraying and tumbling in a rotating drum. The prills or granules may be further dried, cooled, and then coated to prevent caking. These prills or granules are the typical AN products in commerce.
In Floyd's plant they produced their own ammonia. Here is that process. A typical modern ammonia-producing plant first converts natural gas (i.e., methane) or LPG (liquefied petroleum gases such as propane and butane) or petroleum naphtha into gaseous hydrogen. The method for producing hydrogen from hydrocarbons is known as steam reforming. The hydrogen is then combined with nitrogen to produce ammonia via the Haber-Bosch process. Here is a flow diagram of the process. At left is the process used in Gonzales and at right the process used in Vicksburg. The reformer process used in Gonzales, according to Floyd, reduced the production cost for a ton of ammonia from $50 to $9!
Below we learn from Floyd the nuts and bolts of these processes. It is clear from Floyd's description that the simple chemical reaction shown above, entails many, many complex and at times dangerous processes to realize the finished product. For those familiar with fertilizer rating from the nursery, ammonia nitrate is rated, 34-0-0. (34% nitrogen)
The flow process is shown at the end of Floyd's article.
A WORKING EDUCATION
The first year out of high school I worked for an oil exploration company. l liked the work but it was travel — travel — travel. I learned how to use explosives and how to drill holes in the ground. I learned to survey a line to set test patterns for the oil survey.
Lots of fun and things to learn, but I did not want to be traveling all my life.
After that I work in U. S. Waterways Experimental Station. a government soils laboratory, for a year. Interesting work, but without a college education it was going nowhere. I was playing on the Spencer Chemical basketball city league team. My high school classmate, Ted Porter, was working at Spencer Chemical and he had got me to come join the team as they were short of players. During this time I got to know the workers at Spencer and also the personnel man who was the coach.
He asked me if I would be interested in a job and I said sure. Their pay was better and it sounded like a very interesting place to work and learn.
I had been at Watetways a year when an opening came up at Spencer. I was quick to accept and was soon working at my new job.
The starting job at Spencer, that l was put on, was in the ammonia plant. The ammonia plant had two large boilers that had to have pure water. (Note in the ammonia flow diagram above that steams enters at the top. This has to be free of impurities such as calcium and magnesium.) The job I had was all water treatment. It also included looking after the cooling tower, which cooled and pumped the circulating water for the many heat exchangers used in the production of ammonia. l was also responsible for checking on the two main air compressors and one nitrogen compressor. These compressors also had steam surface condensers that had to be checked also. Readings from all this had to be made every hour. If you stayed on the run for an hour, you could just make a round and take care of water treating duties.
The cooling tower had six fans that ran all the time except during freezing weather. Shutting down some fans in winter to keep water at the proper temperature was standard procedure.The fun came during freezing weather when water spray would freeze on the steps you went up to get to the switches that shutdown the fans. lce cleats had to be strapped to your feet to make the climb. Chemicals were added to the water as per the laboratory reports daily. We circulated thousands of gallons of water per minute.
The water treating was the hot lime process. Steam, city water and lime were mixed in a large tank. Samples had to be run on all the water that exited the mixer going to three carbon/coal filters that removed the solids from the water. It then went through three zeolite softeners. The waters exiting these softeners were at zero in hardness. It was pumped to the storage tank to supply the boilers. The softeners were regenerated with a salt solution that we mixed in a small tank and pumped it through the zeolites. While working in this job, I was required to work with the outside gas generation man and learn that job. I wore out shoes at a three month rate.
Chemical samples on all the water treating had to be done in an open shed in the weather. It was hard to keep chemical and samples from freezing. we kept wrapping the shed with paper sacks until management finally walled it in. I spent some time physically laying on hot pipe to keep warm when the temperature got to 15° degrees.
When I moved up to the gas generation job, I was dealing with a extremely dangerous combination of natural gas and oxygen. To produce hydrogen we took methane and preheated it to 300° and preheated oxygen and fed it into the six generators that produce the hydrogen.
Gas exited the generators through water scrubbers to cool it and also to collect carbon dust generated by the partial oxidation process. The gases then entered a converter filled with catalyst to convert the carbon monoxide in the gas to carbon dioxide. It then went into a very large scrubber that had monoetholamine in solution. This solution, when cool, would absorb carbon dioxide out of the gas stream. The monoetholamine was then heated and passed through a stripper tower that removed the carbon dioxide from the solution. When an opening came available, I was moved up to this gas generation B job. l had to train my replacement at water treatment before I left.
In the gas generation area, we had six firebrick generators that methane and pure oxygen were burned inside. The burners were water cooled, but the burner tips would go bad and the burner would have to be changed. A burner change caused a reduction in production so speed in changing a burner was valuable. A burner change time record was kept so you were competing with the record at a burner change. With new gauge we were able to set a new record, but we (usually a 2 man crew) were not happy with the record, we wanted an unbreakable record. When we caught another burner change on the night shift, I had lined up two more operators from the spensol area to slip into our section and give us a hand. Needles to say it was an impressive time. That record
stood till the plant was shut down.
When a generator was shut down, the inside brick would be about 2200–2400 degrees We had to be sure the boot quench water level did not get high and cool off the inside of the generator. About 1800 degrees was required to ignite the gases on restart. Below that a preheat burner had to be installed and production would be lost. After closing the methane and oxygen block valves, the steam aspirator was open and a vacuum was pulled through the generator burner by way of vents on the gas and oxygen lines. We had to hurry up and unbolt the burner and chain hoist it out of the generator. Once out, the vacuum was reduced to a bare minimum so we could install a new burner. Most of the heat was lost before the burner was out because we had no way to check on the draft amount.
After doing this several times I had a friend get me a vacuum gauge and we put it just under the aspirator. With a little trial and error we were able to establish a reading that reduced the loss of temperature and time involved in changing burners.
When the generator was put in service the flow of oxygen and methane were lined up to vent, and the proper ratio were established so that when it was switched into the generator it would burn at the proper ratio. Once it got to temperature it was switched from exit the generator to the process flow. The analyzer was put into service and started sampling the gas exiting the generator. The ratio controller was adjusted to bring the percentage of excess methane to the proper amount. The ratio controller would shut down the generators if it went to high or too low.
The main catalyst converter in gas generation was the carbon monoxide converter or CO—OX as we called it, which converted the CO to carbon dioxide. Steam was injected in the gas stream into the converter to supply the gas with oxygen to convert carbon monoxide to carbon dioxide. A byproduct was a gain in hydrogen.
While learning the B outside gas job, you were expected to learn the A job or inside gas generation. The major challenge was the B job, as the A job were just part of the process. One thing to note here, we worked in a very noisy area. We had no radio to communicate with, so a hand signal system had been developed. All command signals had a certain meaning.
My next B job with refrigeration. We were in charge of the ammonia product coming off the unit. Production was around 10 tons per hour, and we had dual collection tanks which would hold about 20,000 pounds of ammonia. This meant we had to switch the product into a different tank about every two hours and transfer the product to storage or to the other parts of the plant that used ammonia as their base product. There were three units: UREA, nitric acid and ammonium nitrate which was use to make the end product, which was called SPENSOL. To get the ammonia to travel to the Spensol-nitrate, nitric acid and urea areas, we needed 300 lbs pressure on our tank. This was accomplished using a steam heated heater, called a side-arm heater, because it took ammonia off the bottom of the tank and piped it through the steam heater and back into the tank. When steam was applied, it raised the pressure to 300 psi, and was controlled with an automatic controller.
Refrigeration was supplied by two steam turbines, which drove Freon compressors. Each compressor had a 500 ton capacity. Most of the time both units were needed to supply our needs.
There were several chillers that used liquid ammonia for cooling. Two were incorporated into the air separation plant. They condensed water out of the air that was used to make oxygen and nitrogen.
The Freon units were used re-condense the ammonia that was flashed off in the chillers and recycle to the chillers as a liquid by Pumps. There were four Horton spheres that ammonia was stored under pressure for future use or shipment. We loaded lots of trucks and tank cars.
While working this B job, I was also training on the ammonia conversion section where hydrogen and nitrogen weres converted to ammonia. This conversion took place at approximately three thousand PSI. Conversion was around 10% so you were continuously re-circulating gas through the unit.
During the time that I work at the three B’s jobs, I was able to learn how to operate the A gas generation job, the boiler job, the air separation job and the compressor job. When I made A operator, I took over the BOILER job and Charles O’Connor who had been assigned to boilers on a temporary plan was return to the UREA plant.
I work the BOILER job several months until the ARGON unit, that was being built, was getting close to completion. None of the other A operators on my shift wanted to have to learn and worry with a new product and learn a new process, so I was assigned to the new job. ARGON was a small unit but was very complicated. Gas was supplied to the argon compressor from the impurties vent from the bottom of nitrogen wash tower. This tower took impurities out of the hydrogen gas and burned it in a flare stack. There was a large percentage of argon in this gas and argon was much in demand.
The ARGON had to be liquefied from the gases that were mixed with methane, carbon monoxide nitrogen, and hydrogen. The reclamation columns separated these gases for the most part and a couple of later process purifications took place to purify the argon. In the final cleanup of the argon, the traces of oxygen were converted to water after being mixed with hydrogen and passed over a platinum catalyst. The water was condensed out as the argon went to the last cold column to be liquefied for product.
The argon liquid was stored in an insulated tank at -300°F and 150 PSI. After the argon unit was lined out and running smoothly, another operator on the shift wanted to learn it, so I trained him and took over the a job on the air separation plant. As I have already mentioned, there was no training for this job. The air separation plant used over 1 million SCFM of air into the coldbox to separate the nitrogen and oxygen. The nitrogen was used in the conversion of hydrogen into ammonia and the oxygen was burned with natural gas to produce hydrogen gas.
Expanders and Oxygen Pump, Spencer Chemical Plant, Vicksburg. Here air is condensed, cooled, expanded and condensed into liquid oxygen and liquid nitrogen. Inside the white rectangular building is where the liquifaction takes place. Below are two diagrams showing the process. They demonstrate the process in two different ways, the first two diagrams are the Linde process for air. Further cycling and cooling will liquify first nitrogen which is bled off and then oxygen. In the picture above two black cylinders with white spots at the lower left of the building are oxygen pumps. The large white pipe at top of building carries the compressed air into the liquifier. Note the array of control valves on side of the building. These could be used to take a pipe out of the system that had frozen up andto heat and purge it. All this was done outside as can be seen with no shelter to proect operator from rain, storms, sleet, cold wind, etc.
Spencer had three of the ammonia storage tanks in Vicksburg.
This is the nitrogen wash tower where the nitrogen gas was purified before it was made into ammonia. This was where the big white line from O2 plant