How Does calcium carbide manufacturing plant Work?

Chemical compound Calcium carbide Names Preferred IUPAC name Calcium acetylide Systematic IUPAC name Calcium ethynediide Other names

• Calcium percarbide
• Calcium carbide
• Calcium dicarbide

Identifiers

• 75-20-7 Y

3D model (JSmol) ChemSpider

•  Y

ECHA InfoCard 100.000.772 EC Number

• 200-848-3

PubChem CID UNII

• 846WNV4A5F Y

CompTox Dashboard (EPA)

• InChI=1S/C2.Ca/c1-2;/q-2;+2 YKey: UIXRSLJINYRGFQ-UHFFFAOYSA-N Y
• InChI=1/C2.Ca/c1-2;/q-2;+2Key: UIXRSLJINYRGFQ-UHFFFAOYAI

• [Ca+2].[C-]#[C-]

Properties CaC2 Molar mass 64.100 g·mol−1 Appearance White powder or colorless crystals, grey/brown/black crystals if impure Density 2.22 g/cm3 Melting point 2,160 °C (3,920 °F; 2,430 K) Boiling point 2,300 °C (4,170 °F; 2,570 K) Reacts to produce Acetylene Structure[1] Tetragonal (I phase)
Monoclinic (II phase)
Monoclinic (III phase) I4/mmm (I phase)
C2/c (II phase)
C2/m (III phase) 6 Thermochemistry Std molar
entropy (S⦵298) 70 J/(mol·K) Std enthalpy of
formation (ΔfH⦵298) −63 kJ/mol Hazards Occupational safety and health (OHS/OSH): Main hazards Reacts with water to release acetylene gas[2] GHS labelling: Danger H260 NFPA 704 (fire diamond) 305 °C (581 °F; 578 K) (acetylene) Related compounds Related compounds Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y   (what is YN ?) Chemical compound

Calcium carbide, also known as calcium acetylide, is a chemical compound with the chemical formula of CaC2. Its main use industrially is in the production of acetylene and calcium cyanamide.[3]

You can find more information on our web, so please take a look.

The pure material is colorless, while pieces of technical-grade calcium carbide are grey or brown and consist of about 80–85% of CaC2 (the rest is CaO (calcium oxide), Ca3P2 (calcium phosphide), CaS (calcium sulfide), Ca3N2 (calcium nitride), SiC (silicon carbide), C (carbon), etc.). In the presence of trace moisture, technical-grade calcium carbide emits an unpleasant odor reminiscent of garlic.[4]

Applications of calcium carbide include manufacture of acetylene gas, generation of acetylene in carbide lamps, manufacture of chemicals for fertilizer, and steelmaking.

Production

[edit]

Calcium carbide is produced industrially in an electric arc furnace from a mixture of lime and coke at approximately 2,200 °C (3,990 °F).[5] This is an endothermic reaction requiring 110 kilocalories (460 kJ) per mole[6] and high temperatures to drive off the carbon monoxide. This method has not changed since its invention in :

CaO + 3 C → CaC2 + CO

The high temperature required for this reaction is not practically achievable by traditional combustion, so the reaction is performed in an electric arc furnace with graphite electrodes. The carbide product produced generally contains around 80% calcium carbide by weight. The carbide is crushed to produce small lumps that can range from a few mm up to 50 mm. The impurities are concentrated in the finer fractions. The CaC2 content of the product is assayed by measuring the amount of acetylene produced on hydrolysis. As an example, the British and German standards for the content of the coarser fractions are 295 L/kg and 300 L/kg respectively (at 101 kPa pressure and 20 °C (68 °F) temperature). Impurities present in the carbide include calcium phosphide, which produces phosphine when hydrolysed.[7]

This reaction was an important part of the Industrial Revolution in chemistry, and was made possible in the United States as a result of massive amounts of inexpensive hydroelectric power produced at Niagara Falls before the turn of the 20th century.[8] The electric arc furnace method was discovered in by T. L. Willson, and independently in the same year by H. Moissan.[9][10][11] In Jajce, Bosnia and Herzegovina, the Austrian industrialist Josef Kranz and his "Bosnische-Elektrizitäts AG" company, whose successor later became "Elektro-Bosna", opened the largest chemical factory for the production of calcium carbide at the time in Europe in . A hydroelectric power station on the Pliva river with an installed capacity of 8 MW was constructed to supply electricity for the factory, the first power station of its kind in Southeast Europe, and became operational on 24 March .[12]

Crystal structure

[edit]

Calcium carbide is a calcium salt of acetylene, consisting of calcium cations Ca2+ and acetylide anions −C≡C−. Pure calcium carbide is a colourless solid. The common crystalline form at room temperature is a distorted rock-salt structure with the C2−2 units lying parallel.[13] There are three different polymorphs which appear at room temperature: the tetragonal structure and two different monoclinic structures.[1]

Applications

[edit]

Production of acetylene

[edit]

The reaction of calcium carbide with water, producing acetylene and calcium hydroxide,[5] was discovered by Friedrich Wöhler in .

CaC2(s) + 2 H2O(l) → C2H2(g) + Ca(OH)2(aq)

This reaction was the basis of the industrial manufacture of acetylene, and is the major industrial use of calcium carbide.

Today acetylene is mainly manufactured by the partial combustion of methane or appears as a side product in the ethylene stream from cracking of hydrocarbons. Approximately 400,000 tonnes are produced this way annually (see acetylene preparation).

In China, acetylene derived from calcium carbide remains a raw material for the chemical industry, in particular for the production of polyvinyl chloride. Locally produced acetylene is more economical than using imported oil.[14] Production of calcium carbide in China has been increasing. In output was 8.94 million tons, with the capacity to produce 17 million tons.[15]

In the United States, Europe, and Japan, consumption of calcium carbide is generally declining.[16] Production levels in the US during the s were 236,000 tons per year.[13]

Production of calcium cyanamide

[edit]

Calcium carbide reacts with nitrogen at high temperature to form calcium cyanamide:[5]

CaC2 + N2 → CaCN2 + C

Commonly known as nitrolime, calcium cyanamide is used as fertilizer. It is hydrolysed to cyanamide, H2N−C≡N.[5]

Steelmaking

[edit]

Calcium carbide is used:

• in the desulfurization of iron (pig iron, cast iron and steel)[7]
• as a fuel in steelmaking to extend the scrap ratio to liquid iron, depending on economics.
• as a powerful deoxidizer at ladle treatment facilities.

Carbide lamps

[edit] Main article: Carbide lamp

Calcium carbide is used in carbide lamps. Water dripping on carbide produces acetylene gas, which burns and produces light. While these lamps gave steadier and brighter light than candles, they were dangerous in coal mines, where flammable methane gas made them a serious hazard. The presence of flammable gases in coal mines led to miner safety lamps such as the Davy lamp, in which a wire gauze reduces the risk of methane ignition. Carbide lamps were still used extensively in slate, copper, and tin mines where methane is not a serious hazard. Most miners' lamps have now been replaced by electric lamps.

Further reading:
Key Questions to Ask When Ordering 3, 4 Difluorobenzonitrile

If you want to learn more, please visit our website NEW OCEAN GROUP.

Carbide lamps are still used for mining in some less wealthy countries, for example in the silver mines near Potosí, Bolivia. Carbide lamps are also still used by some cavers exploring caves and other underground areas,[17] although they are increasingly being replaced in this use by LED lights.

Carbide lamps were also used extensively as headlamps in early automobiles, motorcycles and bicycles, but have been replaced entirely by electric lamps.[18]

Other uses

[edit]

Calcium carbide is sometimes used as source of acetylene, which like ethylene gas, is a ripening agent.[19] However, this is illegal in some countries as, in the production of acetylene from calcium carbide, contamination often leads to trace production of phosphine and arsine.[20][21] These impurities can be removed by passing the acetylene gas through acidified copper sulfate solution, but, in developing countries, this precaution is often neglected.

Calcium carbide is used in toy cannons such as the Big-Bang Cannon, as well as in bamboo cannons. In the Netherlands calcium carbide is used around new-year to shoot with milk churns.[22]

Calcium carbide, together with calcium phosphide, is used in floating, self-igniting naval signal flares, such as those produced by the Holmes' Marine Life Protection Association.

Calcium carbide is used to determine the moisture content of soil. When soil and calcium carbide are mixed in a closed pressure cylinder, the water content in soil reacts with calcium carbide to release acetylene whose pressure can be measured to determine the moisture content.[23][24]

Calcium carbide is sold commercially as a mole repellent.[25] When it comes into contact with water, the gas produced drives moles away.[26]

References

[edit]

Acetylene is one of the most popular gases used across industries for oxy-acetylene welding and cutting. It is also used as a raw material for the production of various chemicals such as polyester plastics, polyurethane, and more. Acetylene gas is colorless and odorless when pure. Industrial acetylene has a distinctive odor and is combustible in nature. Today, this gas is produced in large volumes using acetylene gas plants. Are you eager to know its production process? This post discusses the process in detail.

Chemical Reaction and Raw Materials

Acetylene is made of two hydrogen and two carbon atoms and is chemically represented as C2H2. This hydrocarbon is produced by one of two processes— chemical reaction or thermal cracking, using different types of raw materials. Calcium carbide is the most popular raw material used for the commercial production of acetylene. It is created by mixing lime and coke in a blast furnace. The product manufactured is calcium carbide. It is reacted with water to create acetylene gas, and this reaction can be easily formulated as CaC2 + 2H2O → C2H2 + Ca (OH)2. Acetylene, calcium hydroxide and heat are the byproducts of this reaction.

The thermal cracking process, on the other hand, makes use of natural gases, including naphtha, crude oil, bunker C, and more. These gases are subjected to a high temperature for producing acetylene, hydrogen, carbon dioxide, carbon monoxide, and more. Acetylene is separated by dissolving the product in solvents such as anhydrous ammonia, water, acetone, or chilled methanol.

This post focuses only on the production of acetylene in plants using the chemical reaction process.

Detailed Information on the Production of Acetylene in Acetylene Gas Plants

Acetylene plants may vary in design; however, in general, they are equipped with the following components and parts, which play a significant role in acetylene production:

1. Hopper Filling Cart
2. Air Operated Hoist
3. Acetylene Generator
4. Cooler Condenser
5. Ammonia Scrubber
6. Medium Pressure Drier
7. Acetylene Purifier
8. Purifier Scrubber
9. Acetylene Compressor
10. High Pressure Driers
11. High-Pressure Filter
12. Back Pressure Relief Valve Air Compressor
13. Flame Arresters
14. Charging Manifolds
15. Air Compressor
16. Pneumatic Acetone Pump
17. Pneumatic Slurry Pump

The process begins with the loading of calcium carbide in a cart. Different sizes of calcium carbide are used in the process. Here is the process described in steps:

Contact us to discuss your requirements of calcium carbide manufacturing plant. Our experienced sales team can help you identify the options that best suit your needs.

1. After loading the cart, it is loaded to the acetylene generator hopper.
2. In the next step, the calcium carbide is mixed with water and acetylene gas is produced instantly. The calcium carbide is added using a carbide feed mechanism that operates by sensing the pressure inside of the generator body. As the pressure drops after the carbide is added additional carbide is added to sustain the reaction and keep acetylene flowing in the process stream.
3. The gas produced in the process is passed through the cooler condenser, which uses pipes surrounded by water to cool the acetylene stream as it passes through the pipes inside the cooler.
4. The ammonia scrubber uses water to remove ammonia in the acetylene stream. By doing this before the purifier the purification material will last 5 times longer. Because both the cooler and ammonia scrubber lower the temperature of the acetylene stream there is little water left in the stream.
5. The medium pressure drier is then used to extract moisture until the correct amount needed for the purification process is left. Calcium chloride is the medium used to remove the moisture.
6. Later, the dried acetylene is passed through the acetylene purifier, where impurities such as phosphine, arsine, H2S are removed from the gas. If industrial acetylene is needed the purification process can be bypassed.
7. Finally, the purified acetylene goes through the purifier scrubber to remove any purifying material that may have escaped the purifier.
8. The acetylene then enters the compressor and is raised from inlet pressure to desired final cylinder pressure by passing through 3 stages of compression.
9. The acetylene stream passes through a set of high-pressure driers that remove any traces of oil and perform moisture removal. Without this final moisture removal, water would be transferred to the cylinders.
10. As the acetylene travels at high pressure to the manifolds it passes through flame arresters on each side of every shutoff valve. In high pressure, acetylene valves are the cause of most ignitions and the flame arresters are positioned to stop the flame as quick as possible therefore limiting the potential for damage to the system.
11. The acetylene is compressed into a cylinder that has liquid acetone and a porous monolithic mass filler. This acetone in the filler allows there to be 25 times more acetylene in the cylinder than if there was no acetone.
12. The ratio of acetone and acetylene will always be constant, but the total amount of acetone will vary due to cylinder size.
13. The air compressor supplies compressed air to operate the acetone pump, lime slurry pump and the actuated ball valves in the acetylene plant.