花園煤礦0.9Mta新井設(shè)計(jì)含5張CAD圖.zip,花園,煤礦,0.9,Mta,設(shè)計(jì),CAD 英文原文 Processing of coal mine gas with low methane concentrations for use in high-temperature fuel cells Torsten Brinkmann, Carsten Scholles, Jan Wind, Thorsten Wolffa, Andreas Dengel, Wulf Clemens Institute of Polymer Research, GKSS Research Centre Geesthacht GmbH, Max-Planck-Stra?e 1, 21502 Geesthacht, Germany Tel. +49 (0) 4752 872400; Fax: +49 (0)4752 872444; email: torsten.brinkmann@gkss.de STEAG Saar Energie AG, Technische Innovation, St. Johanner Stra?e 103, 66115 Saarbrücken, Germany OTS Ingenieurgesellschaft mbH, Lessingstra?e 28, 66121 Saarbrücken, Germany Received 15 January 2007; Accepted 20 February 2007 Abstract Coal mines are emitting off-gases containing methane of varying content. For environmental as well as economical reasons the gas should be collected and put to further use, i.e., as a feed stock for gas engines or fuel cells. Certain concentration ranges of the coal mine gas require an adjustment of the methane content due to safety related and technical constraints. The application of gas permeation is one possibility to increase the methane content to the desired levels. Employing methane selective, silicone-based, high-flux membranes is currently being investigated by a German project consortium. Experimental results as well as simulation studies showed that selectivity and flux of the membrane are sufficient to increase the methane content to the desired value at a reasonable recovery. Keywords: Gas permeation, methane recovery 1. Introduction Coal mines are emitting off-gases containing methane. The methane concentrations range from 20 vol.% for coal seam methane (CSM) from active mines to 80 vol.% for coal mine methane(CMM) from closed-down mines. As such it can be considered as an energy-rich resource and is collected by suction systems to be fed into pipelines for domestic and industrial consumption as well as to decentralised power generation units as gas engines or high-temperature fuel cells. Within Germany an additional benefit is that methane emitted from coal mines counts as a renewable energy and hence falls under the renewable energy legislation with the associated economical benefits. Another important reason for drawing off the emitted methane is its ecological impact when vented to the atmosphere: methane is 20 times more harmful a greenhouse gas compared to carbon dioxide. However, methane contents below 35 vol.% cannot be used in gas engines and fuel cells. An additional aspect is safety: depending on methane and oxygen concentrations, the coal mine gas might form an explosive mixture. In these cases suction and/or compression of the gas is prohibited by safety regulations and the gas is vented to the atmosphere for operating mines whilst the recovery is simply being stopped for closed down mines. One possibility to increase the methane content and hence prevent venting of the gas is to apply a gas permeation process using methane selective membranes. Steag Saar Ener-gie, an operator of coal mine gas pipeline networks and power plants in the German Federal State Saarland, the engineering consultant OTS and the GKSS Research Centre Geesthacht GmbH formed a consortium to investigate this technology. In a second stage of the project, the E&C Company Borsig Membrane Technology is also involved. The project is funded by the German Ministry of Economics and Technology. 2. Process description and process design Feeding the gas into a pipeline at a pressure of 9 bar is conducted in a two-stage process. In the first stage gas is drawn from the coal mines by blowers. Subsequently compressors provide the pipeline pressure. The oxygen content of the gas defines concentration ranges for which certain compression stages are allowed. Hence there are several possible options for integrating a membrane unit into the process. It was decided to design a pilot process possessing the flexibility to be employed at different pressure levels. Furthermore, two membrane modules can be installed so that two-stage operation is possible. Fig. 1 shows a simplified flowsheet of the pilot plant. The feed gas can be directed to either of the two membrane modules by means of valves. The driving force for the high pressure stage is generated by compressors. The permeate is at a pressure of 1.3 bar and either forms the methane enriched product gas or, in case the required methane content cannot be achieved by one-stage operation, is fed to a second low-pressure stage. For this stage a vacuum pump operating at a pressure of 150 mbar supplies the driving force. A recycle compressor can be employed to feed the retentate of the low-pressure stage back to the feed side of the high-pressure stage. If only operation of the blowers is allowed, the low-pressure stage on its own can be employed to upgrade the coal mine gas. The membranes employed are silicone based high-flux membranes. The methane/nitrogen selectivity of this material is limited, but still allows for an increase in methane concentration to the required level of 35 vol.% in the permeate, provided the methane content in the feed is high enough. For the process design, application of GKSS envelope-type membrane modules [1] was assumed. However, in later stages of the project the use of spiral-wound membrane modules is also planned. In order to predict the operating behaviour of the unit, it was modelled using the equation-oriented process simulator Aspen Custom Modeler?. The model employed for simulating the membrane modules accounted for real gas behaviour and concentration-dependent permeation as previously described [2]. Fig. 2 shows the simulated performance of the low-pressure stage. The operating conditions are given in the figure. It is apparent that a methane content exceeding 35 vol.% in the permeate can only be achieved if the methane concentration in the feed is higher than 23 vol.%, when carbon dioxide is present in the feed gas. In case no carbon dioxide is present only 21 vol.% of methane are required in the feed. The carbon dioxide content of the feed gas influences the performance of the gas permeation unit since the permeance of carbon dioxide is considerably higher than that of methane for silicone based membrane materials. Furthermore does carbon dioxide induce swelling of the membrane and hence influences the permeation rates of the other components present. The carbon dioxide content has also an impact on the recovery. With no carbon dioxide present, methane, nitrogen and oxygen are permeating independently. If carbon dioxide is present in the feed the predicted results are different: the membrane is plasticized and additional permeation pathways are being formed. These allow increased amounts of methane pass through the membrane and thus increase recovery, albeit on the expense of a reduced permeate purity. fig. 1. Simplified flowsheet of two stage gas permeation process. Fig. 2. Simplified flowsheet of two stage gas permeation process. For a two-stage process as indicated in Fig. 1 operated with a feed pressure of 9 bar and a feed flowrate of 200 Nm3/h, a feed methane concentration of 16.5 vol.% is required to achieve 35 vol.% of methane in the product at maximum carbon dioxide concentration. Furthermore is the methane recovery positively affected. This performance increase is however at the expense of additional investment and operating costs due to the more complex plant layout and the energy consumption of the recycle compressor. The pilot plant is currently in the commissioning phase at a Steag site. First experimental results obtained from the low-pressure stage indicate that the methane content can be enhanced at a reasonable recovery. The high pressure stage has been delivered to the site and will be tied into the process. Fig. 3 shows a photograph of this stage. Fig. 3. High-pressure stage Fig. 3. High-pressure stage. 3. Conclusions and future work The theoretical studies conducted so far indicate that gas permeation processes can be employed to increase the methane content of coal mine gas so that it can be employed as a feed stock for decentralised power generation units. However, various process parameters as well as overall performance have to be evaluated by means of pilot plant operation. Aspects to be investigated include: （1）use of different membrane module types, i.e. envelope type and spiral wound; （2）validation of simulation tools by pilot plant data;influence of the carbon dioxide content on the performance; （3）control of the unit with respect to safetyrelevant changes in methane and oxygen con centrations in the feed and the resulting influence on the quality of the product (permeate) gas; （4）long-term stability of the membrane process with respect to "real world" operation, i.e.assessment of the influence of changing compositions, possible condensation and entrainment of dust or compressor oil on the operating performance; （5）economical evaluation of the process. References [1] W. Hilgendorff, G. Kahn and J. Kaschemekat, DE Pat3507908 C2, 1988. [2] T. Brinkmann, Modellierung und Simulation der Membranverfahren Gaspermeation, Dampfperme tion und Pervaporation in Membranen, K. Ohlrogge and K. Ebert, eds., Wiley-VCH, Weinheim, 2006. [3] A. Alpers, Hochdruckpermeation mit selektiven Polymermembranen für die Separation gasf?rmiger Gemische, Ph.D. Thesis, University of Hannover, 1997. 中文譯文 高溫度燃料電池處理煤礦低濃度瓦斯 Torsten Brinkmanna, Carsten Schollesa, Jan Winda, Thorsten Wolffa, Andreas Dengelb, Wulf Clemensc 聚合物研究協(xié)會(huì)，GmbH公司GKSS研究中心， 德國，Geesthacht，Max-Planck-Stra?e 電話： +49 (0) 4752 872400; 傳真: +49 (0)4752 872444; 電郵: torsten.brinkmann@gkss.de 摘要:煤礦排出的氣體中包含有不同含量的甲烷，無論是環(huán)境還是經(jīng)濟(jì)因素，我們都應(yīng)當(dāng)收集起來加以利用，比如，可以作為燃料發(fā)動(dòng)機(jī)或者燃料電池的能源。由于安全和相關(guān)技術(shù)方面的限制，我們需要重新調(diào)整煤礦排出的瓦斯氣體的濃度，氣體滲透是一種使甲烷氣體達(dá)到我們期望濃度的一種方法。目前一家德國企業(yè)正在研究利用甲烷的可選擇性，硅樹脂為基礎(chǔ)的高通透膜，實(shí)驗(yàn)結(jié)果，以及模擬研究顯示，選擇性和通透膜足以使甲烷含量達(dá)到一個(gè)理想的值。 關(guān)鍵詞：氣體滲透，甲烷回收 1.導(dǎo)言 煤礦排除的氣體中含有甲烷，甲烷的濃度范圍從活躍礦山煤層甲烷（CSM）的20%到非活躍礦山煤層氣（CMM）的80%。因此，它可被視為一個(gè)能源豐富的資源，通過抽風(fēng)機(jī)壓入管道，為家庭和工業(yè)消費(fèi)以及為分散式發(fā)電單位，燃?xì)獍l(fā)動(dòng)機(jī)或高溫燃料電池提供能源。在德國一個(gè)額外的好處是，甲烷排放的煤礦數(shù)目是一個(gè)可再生能源，因此，復(fù)合可再生能源的立法與相關(guān)的經(jīng)濟(jì)效益。 我們要禁止排放甲烷的另一個(gè)重要原因是其對(duì)生態(tài)環(huán)境的影響，甲烷的溫室效應(yīng)是CO2氣體的20倍，然而當(dāng)甲烷含量低于35%時(shí)不能用于燃?xì)獍l(fā)動(dòng)機(jī)號(hào)和燃料電池，另一方面又是安全的：根據(jù)甲烷和氧氣濃度，煤礦瓦斯可能形成爆炸性混合。在這些情況下，抽風(fēng)機(jī)和/或壓風(fēng)機(jī)違反了安全規(guī)例，將違規(guī)氣體排放出來的煤礦可能被叫停，其中一個(gè)可能性，增加甲烷含量，從而防止排除的氣體適用于氣體滲透過程中使用甲烷選擇性滲透膜。Steag Saar Ener-gie，一個(gè)煤礦瓦斯管道網(wǎng)絡(luò)工作的操作員和在德國的薩爾州的聯(lián)邦國家的發(fā)電廠，工程顧問OTS和GKSS研究中心Geesthacht GmbH公司成立了一個(gè)協(xié)會(huì)來研究這種技術(shù)。在工程的第二階段，E&C Company Borsig Membrane Technology也參與了，該項(xiàng)目的經(jīng)費(fèi)由德國經(jīng)濟(jì)部和技術(shù)提供。 2. 過程描述和工藝設(shè)計(jì) 以大氣壓九倍的壓力將氣體壓入管道的過程經(jīng)歷了兩個(gè)階段的過程，第一階段的氣體來自煤礦風(fēng)機(jī)，隨后空氣壓縮機(jī)提供管道的壓力，瓦斯中氧氣定義了某些壓縮階段允許的含量，因此，有幾個(gè)可能的備選方案集成了膜單位加入這一進(jìn)程。這就決定要在不同的壓力條件下設(shè)計(jì)一個(gè)靈活性的實(shí)驗(yàn)過程。此外，安裝二模組件，使兩個(gè)階段的運(yùn)作是可行的，圖1顯示了一種簡化的流程實(shí)驗(yàn)裝置通過任意一個(gè)模組件的閥可向管道中導(dǎo)入氣體，空氣壓縮機(jī)產(chǎn)生了高壓力，滲透是在1.3巴（巴：氣壓單位=750mm汞柱）氣壓或者任何形式的富化產(chǎn)品下進(jìn)行的，如果所需的甲烷不能在第一階段滿足要求，則壓入第二階段，這一階段由具有150m巴的真空泵提供壓力，可以使用循環(huán)壓縮機(jī)將第一階段未能透析的滯留物壓回到高壓階段，如果僅僅使用鼓風(fēng)機(jī)是可以的，在低壓階段就可以提高煤礦瓦斯含量。 滲透膜是以有機(jī)硅為材料的高通量模膜，對(duì)甲烷/氮具有選擇性的材料室有限的，但是仍然可以將甲烷濃度增加到要求的35%的水平，提供到管道中的甲烷的濃度已足夠高，為工藝設(shè)計(jì)，應(yīng)用GKSS信封式膜組件[1]是假設(shè)，不過，在稍后階段，該項(xiàng)目已計(jì)劃使用螺旋式膜組件。 為了預(yù)言個(gè)體的經(jīng)營行為，這是利用方程的面向過程模擬器Aspen自定義建模的藍(lán)本。該模型利用模擬膜組件，占實(shí)際氣體的情況和濃度依賴性正如先前所描述的[ 2 ] 。圖2顯示了低壓力階段的模擬表現(xiàn)，在數(shù)字中給出了操作條件，很明顯，當(dāng)瓦斯中含有CO2時(shí)，如果甲烷濃度超過23%，滲透才能夠達(dá)到甲烷含量超過35%，在不含有CO2而甲烷含量在21%的情況下，管道中CO2氣體含量影響氣體單位性能，因?yàn)镃O2的對(duì)硅樹脂材料的滲透性比甲烷要高得多，此外，是否是CO2引起了滲透膜的膨脹而導(dǎo)致其他組件的滲透性發(fā)生了變化呢？CO2的含量影響滲透效果。在不含有CO2的情況下，甲烷、氮?dú)?、氧氣的滲透是互不影響的。如果混合氣體中含有CO2，預(yù)測(cè)結(jié)果將是不同的：滲透膜滲透性將增加，而且還會(huì)引起額外的滲透。這雖然影響了滲透的純凈性，但是增加了甲烷的滲透量，提高了甲烷回收率。 圖1 簡化的流程實(shí)驗(yàn)裝置 圖2 低壓力階段的模擬表現(xiàn) 圖1中顯示了兩個(gè)階段的過程，在9巴壓力和氣體流量為200Nm3/h的操作條件下，在CO2濃度最高的情況下甲烷濃度為16.5%混合氣體必須滲透達(dá)到35%的要求，此外就是甲烷回收的顯著效果。需要為工廠建設(shè)和空氣壓縮機(jī)投資運(yùn)營成本。 目前設(shè)于Steag的試驗(yàn)廠正處于調(diào)試階段，從第一實(shí)驗(yàn)階段即低氣壓階段取得的成果來看，甲烷的含量可以提高的一個(gè)合理的水平，高壓力階段已經(jīng)交付試驗(yàn)廠，即將達(dá)到這一階段，圖3的照片顯示了這一階段。 圖3 高壓力階段 3.結(jié)論和未來的工作 理論進(jìn)行的研究表明，到目前為止， 這種氣體的滲透過程可以用于礦井瓦斯以增加甲烷的含量，以便它能夠被用于發(fā)電廠的能源。然而各種實(shí)驗(yàn)參數(shù)和整體表現(xiàn)需要實(shí)驗(yàn)室的各種操作來評(píng)價(jià)，各方面的研究包括： （1）使用不同的膜組件類型，例如：包膜類型和螺旋類型； （2）通過實(shí)驗(yàn)室數(shù)據(jù)進(jìn)行模擬工具的驗(yàn)證；CO2濃的含量對(duì)滲透性的影響； （3）在含有氧氣和甲烷的安全的情況下控制單位量，觀察對(duì)產(chǎn)品質(zhì)量的影響； （4）滲透膜能夠長期穩(wěn)定的工作在“真實(shí)世界”中，即：成分改變對(duì)評(píng)估的影響，可能凝結(jié)或者夾帶粉塵和壓風(fēng)機(jī)油對(duì)操作性能的影響； （5）經(jīng)濟(jì)性評(píng)價(jià)過程。 參考文獻(xiàn) [1] W. Hilgendorff, G. Kahn 和 J. Kaschemekat, DE Pat3507908 C2, 1988. [2] T. Brinkmann, Modellierung und Simulation der Membranverfahren Gaspermeation, Dampfpermetionund Pervaporation in Membranen, K. Ohlroggeand K. Ebert, eds., Wiley-VCH, Weinheim, 2006. [3] A. Alpers, Hochdruckpermeation mit selektiven Polymermembranen für die Separation gasf?rmiger Gemische, 博士研究生論文, 漢諾威大學(xué)，1997.