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XXV. BRÜX

Several bus-loads of staff and workmen from the Hermann Goering Works at Brüx arrived at Leuna on the night of 12/13th May. They had left Brüx on the night of 7th/8th May just before the Russian entry. The party included Dr. Damm, the managing director and Dr. Amon, the chief engineer. Dr. Ottens, the chief chemist of the plant had been separated from the main party en route and was expected later. Dr. Damm had no papers and was in no condition to give a detailed account of the plant and its operations. He disclosed that arrangements had been made in March to evacuate to Schwarzenfeld, near Amberg, Bavaria, in the event that a Russian occupation of Brüx appeared likely. When the Western advance developed, this plan was dropped but but a considerable number of documents were evacuated to the Porceline Fabrik Buchtal A.G. at Schwarzenfeld. A further batch of documents had been sent to the Kohlen Chemische Institut at Claustal in the Hartz Mountains. Others had been hidden in the central shaft of the brown coal mine at Brüx.

It was the intention of the Brüx staff to proceed to the Hermann Goering Works at Walenstadt, near Brunswick, where they hoped to work out a plan for distribution of people to other works.

The plant erection of which was commenced in 1939, consisted of the following sections;

This consisted of four groups of 20 carbonisation units designed by Luri to operate with recycle gas. The coal carbonized was the local hard brown coal containing 30% water. Each unit had a throughput of 250-300 tons/day of wet coal. Parts of this plant commenced operation in 1942 and by May 1944 when the programme began to be interrupted by air raids, 60 units had been erected and 55 were working. Tar yield was 10-12% by weight on the coal carbonized and middle oil and heavy tar were produced separately by fractional condensation of the tar vapours. It was proposed to sell the middle oil as heating oil after topping it to increase the flash point >85°C. The heavy tar was to be the feed to the hydrogenation plant.

Six large Winkler Generators, each with a capacity of 20,000 M³/hour water gas, were installed, together with Linde units for Oxygen manufacture. The hydrogen plant for completion of the reaction CO + H₂O = CO₂ + H₂ operated at 12 ats. pressure. Nine hydrogen plant units were installed at Brüx. They were all Bamag design.

The anticipated steam savings were not achieved and initially trouble was experienced by salting up and corrosion of parts of the plant. Trouble was also experienced with the life of catalyst which had to be removed every 4-6 weeks for cleaning by rumbling and sieving. At times, the operation of the hydrogen units definitely limited plant operation and Dr. Damm was firmly of the opinion that atmospheric pressure hydrogen sets are to be preferred.

The hydrogenation plant was in two sections, each consisting of the two liquid phase stalls, two pre-saturation and two splitting at 325 ats. The anticipated output of final liquid products from this plant, i.e. fuel oil from carbonization + petrol and diesel oil from the hydrogenation units, was 600,000 tons/year. The plant began operations in May 1943 and by May 1944 and brought up to 45,000 tons/month. Bombing commenced in May 1944 and continued at regular intervals. The output of the plant was greatly reduced as a result and in the last 6 months of 1944 was only 20,000 tons of liquid product. The output during 1944 was only 20,000 tons of liquid product. Output during 1944 was 100-120,000 tons. It was considered that, apart from air raid damage, the output of the complete plant could have been easily increased from 600,000 to 1,000,000 tons/year liquid product by the addition of two more liquid phase stalls and by increasing the capacity of the carbonization plant.

(d) Phenol Extractions

The brown coal tar was very rich in phenols. Aqueous liquors produced in the carbonisation and hydrogenation plant were recovered by method developed by Koppers. the product was subjected to steam distillation and the distillate passed through caustic soda solution and maintained at about 100°C, the resulting phenate being worked up in the ordinary way. a third source of phenol was the light oil from the carbonization units, which was extracted with caustic soda.

The phenosolvan extract was very rich in catechol. The crude extract was purchased by the I.G. and was worked up at Leuna. The rest of the caustic soda extracted phenols were worked up at Brüx and sold through the Phenols Sales Board in Berlin. Refining was not carried beyond the crude carbolic acid and crude cresols stages although it was intended later to install plant for the production of pure phenolic products.

Operation of the Hydrogenation Units

The heavy brown coal tar was hydrogenated in much the same way as employed at Leuna. The heavy tar was mixed with the cold catchpot product and fractionated into middle oil boiling up to 325°C and heavy oil, the latter being fed to the liquid phase hydrogenation stalls and hydrogenated, using a suspended iron on Grude catalyst.

The Brüx tar was quite difference from Middle German brown coal tar. In addition to its higher content of phenols, including catachol, it had a considerably higher asphalt content. It was also apt to contain arsenic compounds which gave rise to considerable trouble in the plant. Arsenic compounds were found in deposits in the pre-saturation hydrogenation stall interchangers and on the catalyst. The source of the arsenic was thin bands of high arsenic content Pyrites in the coal. As a temporary measure, trouble was minimized by careful selection of the coal but it was intended to install a coal washery, operating the flotation process in order to remove Pyrites from the coal carbonised.

Dr. Amon stated that ordinary gas-fired preheaters were used for the liquid phase and the splitting hydrogenation stalls but the preheaters for the pre-saturation stalls were electrically heated.

Costs

At the full output of 600,000 tons/year liquid products, it had been calculated that motor gasoline would cost 260 marks/ton at Brüx. This assumes that crude wet coal costs 12 marks/ton delivered, and is made up as follows:

The corresponding cost of heating oil was estimated to be 220 marks/ton.

Present Condition of Brüx Plant

When the staff left Brüx, 16 carbonisation units were capable of operating and another six could have been put on line very quickly. Dr. Damm considered that within 12 weeks, 30 carbonisation units could be in operation. Three Winkler gas Generators were in operating condition and it was estimated that the Linde plant could be made to operate at half capacity in 1-2 months’ time, given freedom from air raids. The same was considered to apply for the hydrogen sets CO₂ and CO removal and compression.

As far as the hydrogenation plant was concerned, one liquid phase unit was in running order and a second could be put on line in four weeks. Two saturation and two splitting hydrogenation stalls were in working order.

Storage tanks had suffered badly in air raids but Dr. Damm considered that sufficient tanks were available for operation of the plant at roughly half its flowsheet output. Most of the storage tanks were sunk about one-third of their height below ground and were surrounded with 18” concrete walls

Underground Hydrogenation Plant

The Hermann Goering Works at Brüx had started work on an underground hydrogenation plant at Bad-Schandau in Polenstal. This plant was intended to make 5,000 ton/month of petrol from tar. It consisted to two liquid phase and two vapour phase stalls and was known as Schwalbe III.

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