Fixed-dome Biogas Plants - Revision history

Lisafeldmann at 09:07, 7 January 2016

2016-01-07T09:07:32Z

Show changes

Ranisha: /* Gas-Holder */

2015-12-03T12:37:46Z

‎Gas-Holder

Ranisha: /* Further Information */

2015-12-03T12:36:10Z

‎Further Information

Ranisha: /* Criteria for the selection of a type and design */

2015-12-03T12:30:33Z

‎Criteria for the selection of a type and design

Ranisha: /* References */

2015-12-03T12:29:55Z

‎References

Ranisha: /* Summary */

2015-12-03T12:29:01Z

‎Summary

Ranisha: /* Overview */

2015-12-03T12:27:52Z

‎Overview

Ranisha: /* References */

2015-12-03T12:27:30Z

‎References

Ranisha: /* References */

2015-12-03T12:27:04Z

‎References

Ranisha at 11:02, 3 December 2015

2015-12-03T11:02:23Z

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 The top part of a fixed-dome plant (the gas space) must be gas-tight. Concrete, masonry and cement rendering are not gas-tight. The gas space must therefore be painted with a [[Plasters and Coats for Biogas Digesters and Gas-holder|gas-tight layer]] (e.g. 'Water-proofer', Latex or synthetic paints). A possibility to reduce the risk of cracking of the gas-holder consists in the construction of a [[Parts of a Biogas Plant#Weak Ring|weak-ring]] in the masonry of the digester. This "ring" is a flexible joint between the lower (water-proof) and the upper (gas-proof) part of the hemispherical structure. It prevents cracks that develop due to the hydrostatic pressure in the lower parts to move into the upper parts of the gas-holder.<br/>
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+[[Types of Gasholders for Biogas Plants#Fixed-dome Gasholders|►Read more.....]]
-[[Fixed-dome_Biogas_Plants#toc|►Go to Top]]<br/>

← Older revision		Revision as of 12:36, 3 December 2015
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	*[[Portal:Biogas\|Biogas Portal on energypedia]]		*[[Portal:Biogas\|Biogas Portal on energypedia]]
		+	*[[:File:Insulation of Fixed-Dome Biogas Digesters in China.pdf\|Insulation of Fixed-Dome Biogas Digesters in China.pdf]]
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-= Criteria for the selection of a type and design =
+= Criteria for the Selection of a Type and Design =
 A biogas plant should serve the owner of the plant. There it must be in any case financially viable, the benefits have to exceed the investment. In addition it has to be user friendly. easy to be fed and to be operated.
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 <br/>
-[[Fixed-dome_Biogas_Plants#toc|►Go to Top]]<br/>
+[[Fixed-dome_Biogas_Plants#toc|►Go to Top]]

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 = References =
-This article is a continuation of the article, [[Types of Biogas Digesters and Plants|Types of Biogas Digesters and Plants]]. For questions regarding the article, please contact the authors of the article, [[Types of Biogas Digesters and Plants|Types of Biogas Digesters and Plants]].
+This article is a continuation of the article, [[Types of Biogas Digesters and Plants|Types of Biogas Digesters and Plants]]. For questions regarding the article, please contact the authors of this article as well as those of the article, [[Types of Biogas Digesters and Plants|Types of Biogas Digesters and Plants]].
 <references /><br/>
 [[Category:Biofuel]]

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 [[Fixed-dome_Biogas_Plants#toc|►Go to Top]]<br/>
 == Summary ==
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 '''Advantages:''' Low initial costs and long useful life-span; no moving or rusting parts involved; basic design is compact, saves space and is well insulated; construction creates local employment. Advantages are the relatively low construction costs, the absence of moving parts and rusting steel parts. If well constructed, fixed dome plants have a long life span. The underground construction saves space and protects the digester from temperature changes. The construction provides opportunities for skilled local employment.<br/>'''Disadvantages:''' Masonry gas-holders require special <span data-scaytid="120" data-scayt_word="sealants">sealants</span> and high technical skills for gas-tight construction; gas leaks occur quite frequently; fluctuating gas pressure complicates gas utilization; amount of gas produced is not immediately visible, plant operation not readily understandable; fixed dome plants need exact planning of levels; excavation can be difficult and expensive in bedrock. Disadvantages are mainly the frequent problems with the gas-tightness of the brickwork gas holder (a small crack in the upper brickwork can cause heavy losses of <span data-scaytid="117" data-scayt_word="biogas">biogas</span>). Fixed-dome plants are, therefore, recommended only where construction can be supervised by experienced <span data-scaytid="118" data-scayt_word="biogas">biogas</span> technicians. The gas pressure fluctuates substantially depending on the volume of the stored g''as. Even though the underground construction buffers temperature extremes, digester temperatures are generally low.'' ''Fixed dome plants can be recommended only where construction can be supervised by experienced <span data-scaytid="119" data-scayt_word="biogas">biogas</span> technicians.''
-''A specific environmental disadvantage is methane emission from the expansion chamber. ''<br/>'''''Variations:''' Some companies are now looking into small <span data-scaytid="124" data-scayt_word="pre-fab">pre-fab</span> fixed dome plants made of <span data-scaytid="125" data-scayt_word="fibreglass">fibreglass</span> which appears to be a low cost alternative'' to construction intensive <span data-scaytid="126" data-scayt_word="masoned">masoned</span> plants. A custom made plant can be produced in 2 days and -after transport- installed in less than 1 day!<br/>
+''A specific environmental disadvantage is methane emission from the expansion chamber. ''<br/>'''''Variations:''' Some companies are now looking into small <span data-scaytid="124" data-scayt_word="pre-fab">pre-fab</span> fixed dome plants made of <span data-scaytid="125" data-scayt_word="fibreglass">fibreglass</span> which appears to be a low cost alternative'' to construction intensive <span data-scaytid="126" data-scayt_word="masoned">masoned</span> plants. A custom made plant can be produced in 2 days and -after transport- installed in less than 1 day!
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-<br/>
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-[[Fixed-dome_Biogas_Plants#toc|►Go to Top]]<br/>
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 *[[Fixed-dome_Biogas_Plants|Fixed-dome Plants]]
 *[[Floating_Drum_Biogas_Plants|Floating-drum Plants]]
-*[[Low-Cost_Polyethylen_Tube_Digester|Low-Cost Polyethylen Tube Digester]]
+*[[Low-Cost_Polyethylene_Tube_Digester|Low-Cost Polyethylene Tube Digester]]
 *[[Balloon_Digester_for_Biogas_Plants|Balloon Plants]]

← Older revision		Revision as of 11:02, 3 December 2015
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−	~~== Horizontal Plants<br/> ==~~
−
−	~~Horizontal <span data-scayt_word="biogas" data-scaytid="20">biogas</span> '''A''''''d''vantages: Disadvantages''': Problems with gas-space leakage, difficult elimination of scum.'''<br/>~~
−
−	~~<br/>~~
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−	~~[[Fixed-dome_Biogas_Plants#toc\|►Go to Top]]<br/>~~
−	~~<blockquote>~~
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−	~~</blockquote>~~
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−	~~== Earth-pit Plants<br/> ==~~
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−	Masonry digesters are not necessary in stable soil (e.g. <span data-scayt_word="laterite" data-scaytid="22">laterite</span>). It is sufficient to line the pit with a thin layer of cement (wire-mesh fixed to the pit wall and plastered) in order to prevent seepage. The edge of the pit is reinforced with a ring of masonry that also serves as anchorage for the gas-holder. The gas-holder can be made of metal or plastic sheeting. If plastic sheeting is used, it must be attached to a quadratic wooden frame that extends down into the slurry and is anchored in place to counter its buoyancy. The requisite gas pressure is achieved by placing weights on the gas-holder. An overflow point in the peripheral wall serves as the slurry outlet'''.''' '''Advantages''': Low cost of installation (as little as 20% of a floating-drum plant); high potential for self help approaches. '''Disadvantages''': Short useful life; serviceable only in suitable, impermeable types of soil.<br/>Earth-pit plants can only be recommended for installation in impermeable soil located above the groundwater table. Their construction is particularly inexpensive in connection with plastic sheet gas-holders.
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−	~~<br/>~~
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−	~~[[Fixed-dome_Biogas_Plants#toc\|►Go to Top]]<br/>~~
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−	~~== Ferrocement Plants ==~~
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−	The <span data-scayt_word="ferro-cement" data-scaytid="24">ferro-cement</span> type of construction can be applied either as a self-supporting shell or an earth-pit lining. The vessel is usually cylindrical. Very small plants (Volume under 6 <span data-scayt_word="m3" data-scaytid="25">m<sup>3</sup></span>) can be prefabricated. As in the case of a fixed-dome plant, the <span data-scayt_word="ferrocement" data-scaytid="85">ferrocement</span> gasholder requires special sealing measures (proven reliability with cemented-on <span data-scayt_word="aluminium" data-scaytid="86">aluminium</span> foil). '''''Advantages''''' '''Disadvantages''': Substantial consumption of essentially good-quality cement; workmanship must meet high quality standards; uses substantial amounts of expensive wire mesh; construction technique not yet adequately time-tested; special sealing measures for the gas-holder are necessary. Ferro-cement <span data-scayt_word="biogas" data-scaytid="29">biogas</span> plants are only recommended in cases where special <span data-scayt_word="ferro-cement" data-scaytid="30">ferro-cement</span> know-how is available. <!-- Navigation Footer --><br/>
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−	~~<br/>~~
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−	~~[[Fixed-dome_Biogas_Plants#toc\|►Go to Top]]<br/>~~


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	<references /><br/>		<references /><br/>

−	~~[[Category:Biofuel]]~~
	[[Category:Biogas]]		[[Category:Biogas]]
		+	[[Category:Biofuel]]