HCl manufacturing :

HYDROCHLORIC ACID : Hydrochloric acid (HCl), also known as

muriatic acid, is a solution of hydrogen chloride in water.

HCl exists in solid, liquid, and gaseous states and is water soluble

in all proportions.

 Benedictine Monk and Basil Valentine in 15th century first

prepared Hydrochloric acid by heating common salt and

sulfuric acid

 Also, Libavius prepared free hydrochloric acid by heating salt

in clay crucibles in 16th century.

 In the 17th century, Johann Rudolf Glauber used NaCl and

H2SO4 for the preparation of sodium sulfate in the

Mannheim process, releasing hydrogen chloride gas as a

by- product.

 Joseph Priestley prepared pure HCl in 1772, and chemical

composition includes hydrogen and chlorine was proven by

Humphry Davy in 1818.

As demand for alkaline substances increased during the

Industrial Revolution in Europe, Nicolas Leblanc developed

cheap large-scale production of sodium carbonate (soda

ash).Using common salt, sulphuric acid, limestone and coal

which releases HCl as a by- product. Until the British Alkali Act

1863 and similar legislation in other countries, the excess HCl

was vented to air. After the passage of the act, waste gas was

absorbed in water, producing hydrochloric acid on an industrial

scale.

 In the twentieth century, the Leblanc process was

effectively replaced by the Solvay process without

hydrochloric acid by-product. Since hydrochloric acid was

already fully settled as an important chemical in numerous

applications, the commercial interest initiated other

production methods, some of which are still used today.

 After the year 2000, hydrochloric acid was mostly made

by absorbing by product hydrogen chloride during a

 chemical manufacturing process such as chlorination of

hydrocarbons.

MANUFACTURIG of HCl :

HCl is manufactured by various methods as follows-

1. From salt and sulfuric acid,

2. Synthesis from hydrogen and chlorine,

3. As by-product from chemical processes,

4. From incineration of waste organics,

https://www.youtube.com/watch?v=HJvn-rH_lLQ swayam

From salt and sulfuric acid:

The sodium chloride is ground in a mill, mixed with current of hot

compressed air to 50°C and liquid sulphuric acid are charged

through a feed inlet through the cover of the furnace.

Continuous Mechanical Muffle furnace.: (A muffle

furnace or muffle oven (sometimes retort furnace ) is a furnace

in which the subject material is isolated from the fuel and all of the

products of combustion, including gases and flying ash.

After the development of high-temperature heating elements and

widespread electrification. New muffle furnaces are electric .)

Hydrochloric acid (HCl) is a clear, colorless, fuming, poisonous,

highly acidic, aqueous solution of hydrogen chloride, HCl. A
saturated solution of hydrochloric contains about 43% HCl and
gives a constant-boiling mixture. It is an extremely corrosive
mineral acid and must be handled in glass or plastic equipment
or in apparatus using special alloys (tantalum, nickel-
molybdenum).

Hydrochloric acid is used in petroleum production, as a chemical

intermediate, in ore reduction, food processing, pickling, and
metal cleaning. It was formerly known as 'spirits of salt'.

In all manufacturing processes for hydrochloric acid another

useful product is obtained along with the acid. In the process
illustrated (right), using a Manheim type furnace, sodium sulfate is
produced.
Key to Figure 1
1) Common salt is added to the furnace.
2) Sulfuric acid inlet by way of a lead-lined tank.
3) Rotating shaft.
4) Rotating stirrers mix reactants.
5) Reaction chamber. The salt and sulfuric acid react to form
sodium sulfate and hydrochloric acid, which comes off as the gas
hydrogen chloride because of the high temperature.
6) Oil burner heats reaction chamber.
7) Combustion gases outlet.
8) Salt cake (sodium sulfate) outlet.
9) Hydrogen chloride gas led off.
10) Hydrogen chloride gas piped into the absorption column
below the packed section.
11) The absorption chamber is packed with Raschig rings made
of glass. On the surface of these rings the hydrogen chloride
combines with water, emitted at the top of the tower (12), to form
hydrochloric acid. This reaction releases heat.
12) Water inlet. The water passes down the packed column and
dissolves the hydrogen chloride gas.
13) Cooling water inlet.
14) Cooling water outlet.
15) Hot concentrated hydrochloric acid passes into the cooler at
the bottom of the column.
16) Cooling water inlet.
17) Cooling water outlet.
18) Cool hydrochloric acid led out to storage tanks.
19) Spent gas vent.

The reaction between sodium chloride and sulphuric acid takes

place at temperatures ranging 500 to 550°C. The product

hydrogen chloride gas is discharged at temperature 600°C and

the by-product sodium sulphate is discharged from the hearth at

about 600°C.

Reactions

1. NaCl + H2SO4 → NaHSO4 + HCl (at temperature=150 °C)

2. NaCl + NaHSO4 → Na2SO4 + HCl (at temp=550 -650°C)

Overall reaction 2NaCl + H2SO4 → Na2SO4 + 2HCl

Since sulphuric acid is more expensive than sodium chloride

(natural salt), it is taken as a limiting reagent and the basis for

the calculations in reactor kinetics,

Conversion of HCl is about 50-60%. Product gas temperatures

from the reactor (furnace) exceed those allowable for

absorption. The method used for absorption varies with the

temperature and volume of the gas being processed. Some

cooling is achieved in the pipeline carrying the gas from the

generating unit to the cooler or cooler-absorber. In the cast-iron

or steel flue carrying the high-temperature gas from the salt-

sulphuric acid process, some heat is removed by radiation to

the atmosphere. In synthesis plants using impervious graphite

 or silica coolers, the pipe may be cooled with external water

sprays. Generally, the high-HCl low-volume gases are cooled

in tubular equipment, and the low-HCl high- volume gases by

heat interchange with concentrated hydrochloric acid in packed

towers.

Hydrochloric acid uses, hazards and industrial applications

Hydrochloric acid is a colourless and odourless solution of

hydrogen chloride and water; with chemical formula HCl. Once

commonly referred to as muriatic acid or spirit of salt, this acid is a

highly corrosive chemical compound with several applications in

industry. Here are some of the interesting properties of HCl

Chemical properties of HCl: Hydrochloric acid is a clear,

colourless, highly pungent solution of hydrogen chloride (HCl) in

water. It is a highly corrosive, strong mineral acid with many

industrial uses. The molar mass being 36.46 g/mol, compound

has a density of 1.18 g/cm3 .

HCl can dissociate (ionize) only once to give up one H+ ion (a

single proton). In aqueous hydrochloric acid, the H+ joins a water

molecule to form a hydronium ion, H3O+.The other ion formed is

Cl−, the chloride ion. Hydrochloric acid can therefore be used to

prepare salts called chlorides, such as sodium chloride.

Hydrochloric acid is a strong acid, since it is essentially

completely dissociated in water.

HCl exists naturally within gastric acid which is one of the main

elements that works in the intestinal tract to digest food and get

rid of secretions in human beings. The gastric acid comprises

primarily of hydrochloric acid which acidifies the stomach

contents.

Chloride and hydrogen ions are secreted separately in the

stomach section which sits at the top of the stomach by parietal

cells of the gastric mucosa into a secretory network known as

canaliculi prior to entering the stomach lumen.

After exiting the stomach, the hydrochloric acid of the chyme is

dissolved in the duodenum by sodium bicarbonate. The intestinal

tract is protected from the strong acid by the secretion of a thick,

protective mucus layer, and by secretin induced buffering with

sodium bicarbonate. If hydrochloride is sent to the oesophagus, it

can aggravate the lining of the oesophagus and lead to the

sensation like peptic ulcers or heartburn.

1. concentration of 600 molar of HCl can kill a person.

2. The concentration of 50 – 150 molar can make a person

blind.

3. Used in activating oil wells: HCl is used in a process known

as oil-well acidization. This process involves injecting the

 acid into the cavities of oil wells to dissolve away sections of

rock, leaving an open column behind. Ultimately, the method

serves to accelerate oil production from the well.

6. One of the strongest commercially available cleaners today

is hydrochloric acid. Hydrochloric acid is extremely powerful

and is recommended as a cleaner. Industrial strength

hydrochloric acid, is commonly used to clean any product that

can withstand its effects.

7. Concentrated HCl is highly corrosive. In laboratories, it is

advisable to apply a barrier cream to the hands prior to use. Keep

it away from any heat source such as burners, ovens, sunlight

etc. Keep containers closed and in an upright position when not in

use. To dilute HCl add the acid to water and store the diluted acid

solution in a reagent bottle (never add the water to the acid). On

industrial scale, label the product, chemical name and chemical

formula. Name the ingredients and formulation details where

relevant. Follow the first aid and emergency procedures. Provide

the details of manufacturer, reference to MSDS and expiry date.