Технический текст "Coal"

Coal 

Coal is a combustible black or brownish-black sedimentary rock composed mostly of carbon and hydrocarbons. Coal is a non-renewable energy source because it takes millions of years to create. The energy in coal comes from the energy stored by plants that lived hundreds of millions of years ago, when the Earth was partly covered with swampy forests.

For millions of years, a layer of dead plants at the bottom of  the swamps was covered by layers of water and dirt, trapping the energy of the dead plants. The heat and pressure from the top layers helped the plant remains turn into what we today call coal.

Coal is classified into four main types, or ranks (anthracite, bituminuos, subbituminous and lignite), depending on the amounts and types of carbon it contains and on the amount of heat energy it can produce. The rank of a deposit of coal depends on the pressure and heat acting on the plant debris as it sank deeper and deeper over millions of years.

Anthracite contains 86 97 % carbon, and generally has a heating value slightly higher than bituminous coal. It accounts for less than 0,5 % of the coal mined in the United States.

Bituminous coal contains 45 – 86 % carbon. Bituminous coal was formed under high heat and pressure. Bituminous coal in the United States is between 100 to 300 million years old. It is the most abundant  rank of coal found in the United States. Bituminous coal is used to generate electricity and is an important fuel and raw material for the steel and iron industries.

Subbituminous coal has a lower heating value than bituminous coal.  It typically contains 35 45 % carbon. Most subbituminuos coal  in the United States is at least 100 million years old. About 46 % of the coal  produced in the United States is subbituminous.

Lignite is the lowest rank of coal with the lowest energy content. Lignite coal deposits tend to be relatively young coal de­posits that were not subjected to extreme heat or pressure, contain­ing 25 – 35 % carbon. It is crumbly and has high moisture content.

Coal miners use giant machines to remove coal from the ground. They use two methods: surface or underground mining. Modern mining methods allow us to easily reach most of our coal reserves.

Surface mining is used to produce most of the coal in the US be­cause it is less expensive than underground mining. Surface mining can be used when the coal is buried less than 200 feet underground.

Underground mining, sometimes called deep mining, is used when the coal is buried several hundred feet below the surface. Some underground mines are 1,000 feet deep.

After coal comes out of the ground, it typically goes on a con­veyor belt to a preparation plant that is located at the mining site. The plant cleans and processes coal to remove other rocks and dirt, ash, sulfur, and unwanted materials, increasing the heating value of the coal.

After coal is mined and processed, it is ready to be shipped to market.

Coal is used to create almost half of all electricity generated in the US. Power plants bum coal to make steam. The steam turns turbines that generate electricity.

A variety of industries use coal's heat and by-products. Sepa­rated ingredients of coal (such as methanol and ethylene) are used in making plastics, tar, synthetic fibers, fertilizers, and medicines.

Coal is also used to make steel. Coal is baked in hot furnaces to make coke, which is used to smelt iron ore into iron needed for making steel. It is the very high temperatures created from the use of coke that gives steel the strength and flexibility for things like bridges, buildings, and automobiles. The concrete and paper indus­tries also use large amounts of coal.

 

Active vocabulary

 

Try to memorize the following words and phrases.

 

Nouns and noun phrases

sedimentary rock                  

carbon                                

pressure

dead plants                            

hydrocarbon                       

remains

top layer                                

content                               

ethylene

coke                                       

anthracite                            

depth

sulfar                                     

lignite                                 

heating value

methanol                               

tar                                       

raw material

deposit                                  

moisture                             

surface mining

steam                                   

flexibility                           

underground mining

synthetic fibers                    

reserves                               

conveyer belt

preparation plant                  

iron ore                              

power plant

 

осадочная порода

углерод

давление

мертвые растения

углеводород

остатки

верхний слой

содержание

этилен

кокс

антрацит

глубина

сера

бурый уголь

теплотворная способность

метанол

смола

сырье

месторождение

влага

открытый способ добычи

пар

гибкость

подземные горные работы синтетические волокна

запасы

конвейерная лента

обогатительная фабрика

железная руда

электростанция

Verbs and verbal phrases

to trap                                         

to create                                     

to sink

to compose of                           

to contain                                   

to account

to mine                                     

to be subjected to                      

to process

 to ship                                        

to bake                                       

to smelt

Adjectives

swampy                                    

bituminous                                

abundant

crumbly                                  

subbituminous                             

expensive 

 

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Last modified: Sunday, 14 December 2014, 12:59 AM