maandag 29 januari 2018

The first transition: from coal to chemicals

It’s often said that DSM started producing chemicals when the Maurits State Mine closed its shafts in 1967. But that is not correct: at the site, which is now Chemelot, chemical production closely followed the mining industry. This changeover was the first transition that was implemented on this site. More transitions would follow.

DSM’s Central Laboratory 1940

Coke oven gas
From 1926 to 1967, coal was mined in the State Mine Maurits in Geleen. The coal from this mine was rich in bitumen. While this rendered it unsuitable for domestic heating purposes, the coal could be processed into cokes for blasting furnaces and foundries. A large coking plant was built, which started production in 1929.

Cooling tower under construction

For cooling purposes use was made of Van Iterson cooling towers with their characteristic hyperboloid form. Towers of this type are still being used worldwide today. Van Iterson (1877-1957) was a DSM director who played a major role in the development of DSM from mining company to chemical company.
It’s fair to say that the cooling tower is the first innovation at Chemelot; more innovations would follow.

In the production of cokes, coke oven gas was obtained, and this gas became the source of several byproducts.:
  • Nitrogen fertilizers
  • Mixed fertilizers
  • Alcohol
  • Phthalic anhydride.
This diversification was deliberate DSM policy because the revenues from mining were rather meager, while only part of the coke oven gas could be sold as town gas to surrounding municipalities. The first form of diversification was the large-scale production of nitrogen fertilizer.

A key fertilizer intermediate is ammonia, which had been produced from gas by the town gas and cokes industries already since the mid-nineteenth century. In 1930, DSM started producing ammonium sulfate fertilizer on the basis of ammonia and sulfuric acid. Use was made of a new technology – the Linde process – to liberate hydrogen from coke oven gas at a low temperature. This hydrogen was subsequently combined with nitrogen from the air to produce ammonia using the Haber-Bosch process. This process was patented in 1910 by the German chemists Fritz Haber (1868-1934) and Carl Bosch (1874-1940). The former received the Nobel Prize in Chemistry for this in 1918. In 1931, Carl Bosch also received the Nobel Prize.
The patent was acquired by the German chemical company BASF.

The ammonium sulfate plant was called Stikstofbindingsbedrijf (SBB – Nitrogen Fixation Works). This proves to be a persistent name, because to date 'SBB' is more known to some than 'Chemelot'.

Oversupply soon resulted in pressure on the selling price of ammonium sulfate, which is why a nitric acid plant was built in combination with a plant that produced calcium ammonium nitrate as from 1932; nitric acid is a necessary intermediate product for this alternative fertilizer, which today is still being used in agriculture in northwestern Europe.
Nitric acid is a necessary intermediate for this. It is produced following the Ostwald process, which was developed in 1906 by Wilhelm Ostwald (1853-1932), who received the Nobel Prize in Chemistry in 1909.
Thanks to fertilizers, DSM gained know-how in the fields of process technology and engineering as well as chemical know-how.

Central Laboratory
Research, including daily quality and process control, took place in plant laboratories, but in 1928 part of the research was centralized in the Central Laboratory, in line with a trend in the chemical industry to set up large, independent departments for fundamental research. Van Iterson had personally identified this trend on his journey through the United States, where he visited companies such as Du Pont.
Between 1939 and 1959, the new Central Laboratory buildings were realized in phases to a design by Fontein; to this day these buildings are the heart of the Chemelot Campus.

The DSM management recognized that research was important if it wanted the company to flourish and to keep up with the competition. Fundamental research initially focused on subjects such as catalysis and crystallization. Catalysis was important for the production of ammonia and nitric acid, and crystallization for the production of ammonium sulfate. Another subject addressed was corrosion, a universal problem in chemical plants.

Falling fertilizer prices pushed the DSM management further on the road to diversification. The next step involved alcohol, which was linked up with the ethylene fraction obtained in the production of hydrogen from coke oven gas. Up to that time, DSM’s plants had been built on the basis of technology purchased from others, but now DSM itself developed a plant for the production of alcohol from ethylene obtained as coke oven gas byproduct – which was a world first. This plant was in production from 1940 to 1960.

Mixed fertilizers
The next diversification step was aimed at mixed fertilizers, in particular fertilizers containing nitrogen and phosphate. The phosphate rock needed for this process had to be imported. The plant was ready for production in 1941, but the first product did not leave the plant until after World War II. In 1949, an NPK plant was commissioned; besides nitrogen and phosphate, this fertilizer also contains potassium.

Phthalic anhydride
Between 1951 and 1963, DSM produced phthalic anhydride, made from a byproduct of the cokes plant, for which there was much demand from the Dutch paint industry after World War II. The required technology was bought from a US-based contractor; DSM no longer wanted to confine itself to in-house technology.

But that was already after the Second World War, a horror that did not go unnoticed by the current Chemelot...

Read also “How it started underground” about the Maurits State Mine.
This is a repost of my (Dutch) August 21, 2017 post.
Read my May 20, 2013 blog post about the reason why of my English reposts.