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A distilling ship is a class of military ships, generally converted
tankers
Tanker may refer to:
Transportation
* Tanker, a tank crewman (US)
* Tanker (ship), a ship designed to carry bulk liquids
** Chemical tanker, a type of tanker designed to transport chemicals in bulk
** Oil tanker, also known as a petroleum tank ...
, with the capability to
convert salt water into fresh water. They were typically stationed at
forward base
A forward operating base (FOB) is any secured forward operational level military position, commonly a military base, that is used to support strategic goals and tactical objectives. A FOB may or may not contain an airfield, hospital, machine sho ...
s during conflict where they supported on-the-ground troops and front line naval units.
Kleinschmidt still
While
steamship
A steamship, often referred to as a steamer, is a type of steam-powered vessel, typically ocean-faring and seaworthy, that is propelled by one or more steam engines that typically move (turn) propellers or paddlewheels. The first steamships ...
s often used the heat in low-pressure
steam
Steam is a substance containing water in the gas phase, and sometimes also an aerosol of liquid water droplets, or air. This may occur due to evaporation or due to boiling, where heat is applied until water reaches the enthalpy of vaporization ...
exhausted from
propulsion
Propulsion is the generation of force by any combination of pushing or pulling to modify the translational motion of an object, which is typically a rigid body (or an articulated rigid body) but may also concern a fluid. The term is derived from ...
machinery to distill fresh water from
seawater
Seawater, or salt water, is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5% (35 g/L, 35 ppt, 600 mM). This means that every kilogram (roughly one liter by volume) of seawater has appro ...
, that was relatively inefficient when the ship was not
underway
Underway, or under way, is a nautical term describing the state of a vessel. "Way" arises when there is sufficient water flow past the rudder of a vessel that it can be steered. A vessel is said to be underway if it meets the following criteria: ...
. Dr. R.V. Kleinschmidt developed a compression
still
A still is an apparatus used to distill liquid mixtures by heating to selectively boil and then cooling to condense the vapor. A still uses the same concepts as a basic distillation apparatus, but on a much larger scale. Stills have been used ...
while working at the
Arthur D. Little
Arthur D. Little is an international management consulting firm originally headquartered in Boston, Massachusetts, United States, founded in 1886 and formally incorporated in 1909 by Arthur Dehon Little, an MIT chemist who had discovered acetate. ...
Laboratories in
Cambridge, Massachusetts
Cambridge ( ) is a city in Middlesex County, Massachusetts, United States. As part of the Boston metropolitan area, the cities population of the 2020 U.S. census was 118,403, making it the fourth most populous city in the state, behind Boston, ...
. These stills were manufactured for the
United States Navy
The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage ...
by E. B. Badger and Sons of
Boston
Boston (), officially the City of Boston, is the state capital and most populous city of the Commonwealth of Massachusetts, as well as the cultural and financial center of the New England region of the United States. It is the 24th- mo ...
. After these Kleinschmidt stills proved successful aboard
diesel engine
The diesel engine, named after Rudolf Diesel, is an internal combustion engine in which ignition of the fuel is caused by the elevated temperature of the air in the cylinder due to mechanical compression; thus, the diesel engine is a so-call ...
d ships like
submarine
A submarine (or sub) is a watercraft capable of independent operation underwater. It differs from a submersible, which has more limited underwater capability. The term is also sometimes used historically or colloquially to refer to remotely op ...
s,
destroyer escort
Destroyer escort (DE) was the United States Navy mid-20th-century classification for a warship designed with the endurance necessary to escort mid-ocean convoys of merchant marine ships.
Development of the destroyer escort was promoted by th ...
s, and
tank landing ship
Landing Ship, Tank (LST), or tank landing ship, is the naval designation for ships first developed during World War II (1939–1945) to support amphibious operations by carrying tanks, vehicles, cargo, and landing troops directly onto shore with ...
s, several stills were placed aboard tankers built as distilling ships.
Seawater enters the
evaporation
Evaporation is a type of vaporization that occurs on the surface of a liquid as it changes into the gas phase. High concentration of the evaporating substance in the surrounding gas significantly slows down evaporation, such as when humidi ...
chamber through two
heat exchanger
A heat exchanger is a system used to transfer heat between a source and a working fluid. Heat exchangers are used in both cooling and heating processes. The fluids may be separated by a solid wall to prevent mixing or they may be in direct contac ...
s. The evaporation chamber has an electrical
heating element
A heating element converts electrical energy into heat through the process of Joule heating. Electric current through the element encounters resistance, resulting in heating of the element. Unlike the Peltier effect, this process is independe ...
used to initially heat the seawater during startup, and the resulting steam is run through a rotary
compressor
A compressor is a mechanical device that increases the pressure of a gas by reducing its volume. An air compressor is a specific type of gas compressor.
Compressors are similar to pumps: both increase the pressure on a fluid and both can transp ...
which increases the steam temperature while creating a vacuum over the seawater in the evaporation chamber to lower the boiling temperature of seawater. The compressed steam is then piped though the evaporation chamber as the primary source of
heat
In thermodynamics, heat is defined as the form of energy crossing the boundary of a thermodynamic system by virtue of a temperature difference across the boundary. A thermodynamic system does not ''contain'' heat. Nevertheless, the term is al ...
so the heating element becomes unnecessary for sustained operation. The compressor maintains a pressure difference of approximately between the boiling seawater and condensing steam which translates to an approximate temperature difference of 5°C (9°F) across the tube walls within the evaporation chamber. Steam condensed while evaporating the seawater is removed as fresh water through one of the heat exchangers pre-heating the incoming seawater, and about twenty percent of the incoming seawater leaves the evaporation chamber as hot
brine
Brine is a high-concentration solution of salt (NaCl) in water (H2O). In diverse contexts, ''brine'' may refer to the salt solutions ranging from about 3.5% (a typical concentration of seawater, on the lower end of that of solutions used for br ...
pumped overboard through another heat exchanger.
[
]
Operational experience
These ships frequently operated in tropical harbors where seawater contained appreciable quantities of pollutant
A pollutant or novel entity is a substance or energy introduced into the environment that has undesired effects, or adversely affects the usefulness of a resource. These can be both naturally forming (i.e. minerals or extracted compounds like oi ...
s. Some of these pollutants would be carried through the compressor as mist from the boiling seawater, and the temperature of the distillation process was inadequate to sterilize the fresh water. Some microorganism
A microorganism, or microbe,, ''mikros'', "small") and ''organism'' from the el, ὀργανισμός, ''organismós'', "organism"). It is usually written as a single word but is sometimes hyphenated (''micro-organism''), especially in olde ...
s carried through to the fresh water were pathogen
In biology, a pathogen ( el, πάθος, "suffering", "passion" and , "producer of") in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ ...
ic, while others colonized the ships' fresh water tanks using nutrient
A nutrient is a substance used by an organism to survive, grow, and reproduce. The requirement for dietary nutrient intake applies to animals, plants, fungi, and protists. Nutrients can be incorporated into cells for metabolic purposes or excret ...
s carried through the compressors to cause taste
The gustatory system or sense of taste is the sensory system that is partially responsible for the perception of taste (flavor). Taste is the perception produced or stimulated when a substance in the mouth reacts chemically with taste receptor ...
and odor
An odor (American English) or odour (English in the Commonwealth of Nations, Commonwealth English; American and British English spelling differences#-our, -or, see spelling differences) is caused by one or more volatilized chemical compounds ...
problems making the water unpalatable Palatability (or palatableness) is the hedonic reward (i.e., pleasure) provided by foods or fluids that are agreeable to the "palate", which often varies relative to the homeostatic satisfaction of nutritional, water, or energy needs. The palatabi ...
. Microbial growth was rapid in the warm water of the tropics. The United States Navy crew would include a naval surgeon
A naval surgeon, or less commonly ship's doctor, is the person responsible for the health of the ship's company aboard a warship. The term appears often in reference to Royal Navy's medical personnel during the Age of Sail.
Ancient uses
Speciali ...
to test and maintain water quality
Water quality refers to the chemical, physical, and biological characteristics of water based on the standards of its usage. It is most frequently used by reference to a set of standards against which compliance, generally achieved through tr ...
.[
A newly cleaned still would produce about 200 gallons of fresh water per gallon of ]diesel fuel
Diesel fuel , also called diesel oil, is any liquid fuel specifically designed for use in a diesel engine, a type of internal combustion engine in which fuel ignition takes place without a spark as a result of compression of the inlet air and t ...
powering the compressor, but accumulation of scale on the brine side of the steam pipes within the evaporation chamber and seawater heat exchanger would typically reduce efficiency to about 100 gallons of water per gallon of fuel after 700 hours of operation.
See also
*
References
Ship types
World War II distilling ships of the United States
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