Everything about Open Hearth Furnace totally explained
Open hearth furnaces are one of a number of kinds of
furnace where excess carbon and other impurities are burnt out of
pig iron to
produce steel. Since
steel is difficult to manufacture due to its high
melting point, normal fuels and furnaces were insufficient and the open hearth furnace was developed to overcome this difficulty. Most open hearth furnaces were closed by the early 1990s, not least because of their fuel inefficiency, being replaced by
basic oxygen furnace or
electric arc furnace.
Technically perhaps, the first primitive open hearth furnace was the
Catalan forge, invented in Spain in the 8th century, but it's usual to confine the term to certain
19th century and later steelmaking processes, thus excluding
bloomeries (including the Catalan forge),
finery forges, and
puddling furnaces from its application.
The Siemens regenerative furnace
Sir
Carl Wilhelm Siemens developed the
Siemens regenerative furnace in the
1850s, and claimed in 1857 to be recovering enough heat to save 70-80% of the fuel. This furnace operates at a high temperature by using
regenerative preheating of fuel and air for
combustion. In regenerative preheating, the exhaust gases from the furnace are pumped into a chamber containing bricks, where heat is transferred from the gases to the bricks. The flow of the furnace is then reversed so that fuel and air pass through the chamber and are heated by the bricks. Through this method, an open-hearth furnace can reach temperatures high enough to melt steel, but Siemens didn't initially use it for that.
The regenerators are the distinctive feature of the furnace and consist of fire-brick flues filled with bricks set on edge and arranged in such a way as to have a great number of small passages between them. The bricks absorb most of the heat from the outgoing waste gases and return it later to the incoming cold gases for combustion.
Open Hearth steelmaking
In
1865, the french engineer Pierre-Emile Martin took out a licence from Siemens and first applied his furnace for making
steel. Their process was known as the
Siemens-Martin process, and the furnace as an "open-hearth" furnace. The most appealing characteristic of the Siemens regenerative furnace is the rapid production of large quantities of basic steel, used for example to construct high-rise buildings. The usual size of furnaces is 50 to 100 tons, but for some special processes they may have a capacity of 250 or even 500 tons. The Siemens-Martin process complemented rather than replaced the
Bessemer process. It is slower and thus easier to control.
Basic oxygen steelmaking or
LD process replaced the open hearth furnace. In the US, steel production using the inefficient open hearth furnaces had stopped by 1992. The highest share of steel produced with open hearth furnaces (almost 50%) still retained in Ukraine. (http://www.energystar.gov/ia/business/industry/41724.pdf).
Further Information
Get more info on 'Open Hearth Furnace'.
|
External Link Exchanges
Do you know how hard it is to get a link from a large encyclopaedia? Well we're different and will prove it. To get a link from us just add the following HTML to your site on a relevant page:
<a href="http://open_hearth_furnace.totallyexplained.com">Open hearth furnace Totally Explained</a>
Then simply click through this link from your web page. Our crawlers will verify your link, extract the title of your web page and instantly add a link back to it. If you like you can remove the words Totally Explained and embed the link in article text.
As long as your link remains in place, we'll keep our link to you right here. Please play fair - our crawlers are watching. Your site must be closely related to this one's topic. Any kind of spamming, dubious practises or removing the link will result in your link from us being dropped and, potentially, your whole site being banned. |
