Distillation disaster

Failure of water pressure can spell disaster in laboratories where some operations, such as distillations, are dependent on water. Ideally, an audible alarm would indicate the lack of water pressure. Laboratory supply houses sell water flow indicators that can be placed in series with the water line to equipment. When water is flowing, a brightly colored ball in a clear tube will move or a small propeller will turn. These can be observed from a considerable distance by watchful laboratory personnel. 

Every year I run a chem lab and when someone is doing a vacuum filtration, suddenly I ll hear a scream and a moan of anguish, as water backs up into someone s filtration system. Usually there s not much damage, since the filtrate in the suction flask is generally thrown out. For vacuum distillations, however, this suck-back is disaster. It happens whenever there s a pressure drop on the water line big enough to cause the flow to decrease so that there is a greater vacuum in the system than in the aspirator. Water, being water, flows into the system. Disaster. 

NOTE - Do not attempt this process unless you are well versed and experienced in conducting reactions and distillations in inert atmospheres, and aware of the natures of the chemicals used. If you do not, you are courting disaster. 

A second explosion occurred in a chemical plant in Texas City, Texas, some years later, and this was called the Texas City Disaster 11. This explosion occurred when a distillation column used to purify butadiene from other C4 hydrocarbons was operating improperly and... 

If the pitch be not well distilled, and a portion of the oleaginous constituents are retained, the fuel, when stowed where the temperature is somewhat elevated, ts apt to ignite spontaneously, in consequence of the evolution and oxidation of those matters. The tendency to this is always greater whan fatty matters or oils have been used with the email coal. Numerous instances of the spontaneous oombustion of artificial fuels, and even of coals, have haen traced to this cause. Such a disaster occurring in the hold of a vessel at sea, is almost certain destruction to the ship. 

The synthesis of arsphenamine was reported by Ehrlich and Bertheim (1912) and it was patented and then manufactured by the firm, Hoechst (DRP 224 953), and sold by them under the name Salvarsan . The initial announcement of a cure for syphilis was taken up by the newspapers, and Ehrlich became a world celebrity overnight. This fame gave him little pleasure, for he had worries that arose from the discovery. For example, arsphenamine was oxidized in the air to a more toxic product, now known to be oxophenarsine 6.4) a much more selective and desirable drug, and one that would in time replace arsphenamine (see Section 6.2). However, at that time, the uncontrolled oxidations were causing deaths, so that Ehrlich decided that arsphenamine must be issued only as single doses, and in sealed tubes from which all oxygen had been removed. He also issued directions for the preparation of solutions in sterile distilled water, neutralization, and intravenous injection without delay. These directions were often departed from, and the resulting disasters attracted unfortunate publicity. Ehrlich later introduced neoarsphenamine ( 914 ), a more soluble derivative. 

Sharing of past major incidents with other oil and gas industries provides useful input data for similar process industries in order to identify the most critical barriers and improve their safety processes. One poignant example highlights this matter. In 1998 there was an accident in the gas compression stage of a Middle East oil and gas plant which caused 7 dead as a result of fuel accumulation and vapor cloud explosion which was very similar to the Texas City Refinery disaster on March 23, 2005 in which a distillation tower was overfilled and an uncontrolled release of hydrocarbons led to a major explosion and fires. Fifteen people were killed and 180 were injured in the worst disaster in the United States in a decade. In both incidents, excess hydrocarbons were diverted into a pressure relief system that included a blowdown stack. In the Iranian case, it was equipped with a flare, but one which the operator didn t ignite in Texas City the blowdown stack was not equipped with a flare to burn off hydrocarbons as they were released. As a result, the flammable overflow from the tower entered the atmosphere. Ignition of the escaped hydrocarbons was enabled by startup of a nearby vehicle resulted in the explosion and subsequent fires (Hopkins, 2008). This example shows the repetitive patterns of accidents, and root causes of events all over the world in this sector. The lesson of this paper is that accidents in one country, where the scenarios are very similar, can and should serve as lessons to prevent the same scenario being actualized in other countries. 

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