TW554160B

TW554160B - Nitrogen generation

Info

Publication number: TW554160B
Application number: TW091117446A
Authority: TW
Inventors: Robert Mathew Alamorian; Joseph Paul Naumovitz; Sudhir Kumar Phakey; Thomas Rathbone
Original assignee: Boc Group Plc
Priority date: 2001-08-09
Filing date: 2002-08-02
Publication date: 2003-09-21
Also published as: US20040244417A1; WO2003014639A1; EP1415118A1; GB0119500D0

Abstract

Air is separated in a single fractionation column 116 to produce a top nitrogen gaseous fraction and a bottom liquid fraction containing less than 80 mole per cent of oxygen. A liquid nitrogen product is also produced. The necessary refrigeration is created by expansion with the performance of external work of firstly a stream of compressed air in an expansion turbine 114 and of secondly a stream of vaporised bottom fraction in an expansion turbine 128. At least part of the feed to the column 116 comes from the turbine 114. The outlet pressure of the turbine 114 is essentially the gaseous nitrogen product pressure. A double fractionation column may be used instead of the single fractionation column 116.

Description

554160 ⑴ 玖、發明說明 (發明說明應敘明:發明所屬之技術領域、先前技術、内容、實施方式及圖式簡單說明) 本發明係有關於氮之生產。更特定言之，本發明係有關於一種在高壓下生產氮產物之方法及裝置。空氣之分離在工業上係一種特別重要的過程，因為分離之產物一主要為氧及氮一有豐富的工業及醫學用途。分離空氣特別常用的方法是在低溫下分餾。低溫空氣分離工廠 I的構造端視產物之純度而定。通常，氧及氮產物二者之純度都需要在99體積％以上。空氣分離工廠的構造也受是否需要液體氧或液體氮所影響。生產相當純產物之空氣分離工廠一般都是特別耗用能量，特別是一些產物必須為液態時。若僅需要氮產物，則一般經濟上很合理的是在氮產物外；不再去生產純氧產物。而代之去分離相當不純之富氧廢空氣產物，工廠設計即可更簡單且能在較生產純氧及純氮產物之工廠為低的資本費用及操作費用下生產一定量之氮產物。因此，所謂的氮生產器一般在設計上與生產純氧及純氮產物二者之空氣分離工廠截然不同。若有需要，氮生產器可利用單分、館或精餾塔。通常而言，係將欲分離之空氣壓縮及純化。所得經壓縮純化之空氣再通入單精餾或分餾塔。在塔中，空氣分離而成為塔頂氣態氮餾份及塔底液體富氧空氣餾份。富氧液體空氣餾份流自單精餾塔底部抽出、通過節流閥膨脹及用於藉間接熱冷凝塔頂氮餾份。此間接熱交換通常會使富氧液體空氣流蒸發。所得蒸發之富氧空氣流在渦輪機中膨脹並 -6- 554160 (2) 進行外功。渦輪機膨脹通常可滿足空氣分離過程之全部冷束需求。氮產物係以氣態取自此一單分麵塔頂部。上述方法之缺點是來自進料空氣之氮產物之回收率不是很高，因為自膨脹渦輪機流出之塔底餾份流會自過程排出。EP-A-4 1 2 793係有關於一種改良，其中並非全部的塔底餾份都在渦輪機中膨脹。代替的是，將自氮冷凝器流出之一部份蒸氣再壓縮並回送至分餾塔。ΕΡ-Α_0 773 4 1 7係有關於一種進一步的改良，其中再壓縮之氣流並非取自單蒸餾塔之塔底液體餾份，而是取自塔之中間區域。其他單塔氮生產器已揭示於US-A-5 611 218及US-A-5 704 229。以上所討論種類之先前技藝氮生產器全部都能生產高壓氮產物而不需要產物壓縮機。單蒸餾塔係安排在進料空氣壓縮之壓力下操作。然而，此種氮生產器之缺點為僅使用單一膨脹渦輪機，而因此不能生產任何實質量之液體氮產物。有時候需要生產多達1 0 %之液態氮產物。在此種情形時，必須使用第二膨脹渦輪機。ΕΡ-Α-0 932 004 (97A63 9) 揭示將已壓縮至單分餾塔之操作壓力下之一部份空氣加至第二膨脹渦輪機，並使進料空氣膨脹至約大氣壓及使膨脹之進料空氣自生產器排出。這種配置之缺點是其會抿消氣體再循環至單分餾塔對氮產物回收率之有益影響。也已知有利用雙分餾塔之氮生產器。例如，US-A-4 717 410揭示雙塔氮生產器，其中全部氮產物都取自高壓塔。為能達到此目的，必須將液態氮自低壓塔頂知泵至高壓塔頂部。此外，必須由外源加入液態氮。因此，根據U S - A - 4 554160554160 玖发明, description of the invention (the description of the invention should state: the technical field, prior art, content, embodiments, and drawings of the invention are briefly explained) The present invention relates to the production of nitrogen. More specifically, the present invention relates to a method and apparatus for producing nitrogen products under high pressure. The separation of air is a particularly important process in industry, because the products of separation-mainly oxygen and nitrogen-have a wealth of industrial and medical uses. A particularly common method for separating air is fractional distillation at low temperatures. The structure of the cryogenic air separation plant I depends on the purity of the product. Generally, the purity of both oxygen and nitrogen products needs to be above 99% by volume. The structure of an air separation plant is also affected by the need for liquid oxygen or liquid nitrogen. Air separation plants for the production of fairly pure products are generally very energy intensive, especially when some products must be liquid. If only the nitrogen product is needed, it is generally economically reasonable to be outside the nitrogen product; no more pure oxygen products are produced. Instead of separating the rather impure oxygen-enriched waste air products, the plant design can be simpler and can produce a certain amount of nitrogen products at lower capital and operating costs than the plants that produce pure oxygen and pure nitrogen products. Therefore, so-called nitrogen generators are generally very different in design from air separation plants that produce both pure oxygen and pure nitrogen products. If required, the nitrogen generator can be used in a single branch, hall or rectification column. Generally speaking, the air to be separated is compressed and purified. The resulting compressed and purified air is then passed to a single distillation or fractionation column. In the column, air is separated into a gaseous nitrogen fraction at the top and a liquid oxygen-enriched air fraction at the bottom of the column. The oxygen-enriched liquid air fraction stream is withdrawn from the bottom of the single distillation column, expanded through a throttle valve, and used to condense the overhead nitrogen fraction by indirect heat. This indirect heat exchange usually evaporates the oxygen-enriched liquid air stream. The resulting vaporized oxygen-enriched air stream expands in the turbine and performs external work at -6-554160 (2). Turbine expansion usually meets all the cooling beam requirements of the air separation process. The nitrogen product was taken in the gaseous state from the top of this single facet tower. The disadvantage of the above method is that the recovery of nitrogen products from the feed air is not very high, because the bottoms stream from the expansion turbine is discharged from the process. EP-A-4 1 2 793 relates to an improvement in which not all of the bottoms fraction is expanded in a turbine. Instead, a portion of the vapor exiting the nitrogen condenser is recompressed and returned to the fractionation column. ΕΡ-Α_0 773 4 1 7 is related to a further improvement, in which the recompressed gas stream is not taken from the bottom liquid fraction of a single distillation column, but from the middle area of the column. Other single tower nitrogen producers have been disclosed in US-A-5 611 218 and US-A-5 704 229. All of the prior art nitrogen producers of the kind discussed above are capable of producing high pressure nitrogen products without the need for a product compressor. The single distillation column system is arranged to operate under the pressure of the feed air compression. However, a disadvantage of this type of nitrogen generator is that it uses only a single expansion turbine and therefore cannot produce any real quality liquid nitrogen product. Sometimes it is necessary to produce up to 10% of liquid nitrogen products. In this case, a second expansion turbine must be used. ΕΡ-Α-0 932 004 (97A63 9) reveals that a portion of the air compressed to the operating pressure of the single fractionation column is added to the second expansion turbine, and the feed air is expanded to about atmospheric pressure and the expanded feed Air is discharged from the producer. The disadvantage of this configuration is that it can eliminate the beneficial effects of gas recycle to the single fractionator on nitrogen product recovery. Nitrogen producers using double fractionation columns are also known. For example, US-A-4 717 410 discloses a two-column nitrogen producer in which all nitrogen products are taken from a high-pressure column. To achieve this, liquid nitrogen must be pumped from the top of the low pressure tower to the top of the high pressure tower. In addition, liquid nitrogen must be added from an external source. Therefore, according to U S-A-4 554160

(3) 717 410之氮生產器絕非液態氮之純生產器，其實際上也消耗液態氮。本發明之目的為提供一種在高壓下生產氮產物之方法（及其所用氮生產器），此法可同時生產液態氮產物而不犧牲氮回收率。根據本發明，其提供者為一種生產氮之方法，其中壓縮空氣係在高壓下分餾而產生產物氮態氮餾份及含少於8 0 φ莫耳％氧之產物富氧液體餾份；氣態氮產物係在高壓下取^ 自氣態氮產物餾份；產物富氧液體餾份流係藉與分餾所分離之冷凝氮間接熱交換而蒸發；液體氮產物係藉冷凝分餾所分離之氮而與氣態氮產物同時生產；及方法之冷凍係由 (i) 壓縮空氣流在第一膨脹渦輪機中膨脹並進行外功，及 (ii) 蒸發之產物富氧餾份流至少一部份在第二膨脹渦輪機；中膨脹並進行外功而產生，其特徵為該壓縮空氣流係在實質超過取得氣態氮產物壓力之壓力下進入第一膨脹滿輪機，但在實質氣態氮產物壓力下離開第一膨脹渦輪機，及在該分餾塔分離之空氣至少一部係由第一膨脹渦輪機供應。本發明也提供一種實行上述方法之氮生產器，包含：一分餾塔，其可運轉產生高壓氣態氮產物及含少於80莫耳％氧之富氧空氣產物，該氮生產器也可同時生產液體氮產物 ;一第一膨脹渦輪機，其係用於使第一壓縮空氣流膨脹並進行外功；一氮冷凝器，其係用於藉由與蒸發之產物富氧液態空氣流間接熱交換以冷凝分餾塔所分離之氮；及一第 554160 (4) 二膨脹渦輪機，其係用於使蒸發之產物富氧空氣膨脹並進行外功，其特別為第一膨脹渦輪機之出口係與分餾塔相通〇將第一膨脹渦輪機佈置成可排卸至分餾塔，即可生產高達至少10%之液態氮產物而不犧牲本發明方法及氮生產器之氮回收率。本發明方法及氮生產器之另一重要優點為所產生之冷凍量而因此與高壓氣態氮產物同時生產之液體氮產物量，可藉由調整流入第一膨脹渦輪機入口之空氣壓力加以改變。此種調整可輕易實行而不改變第一渦輪機之出口壓力，而因此不改變生產高壓氣態氮產物之壓力。在僅使用單膨脹渦輪機之先前氮生產器中並無此種設施之存在，因為並無可調整其入口壓力而不實質影響生產器其他操作參數之設施。同樣地，根據ΕΡ-Α-0 932 004之氮生產器係將其空氣膨脹渦輪機之入口壓力和其分餾塔之操作壓力連在一起，故空氣膨脹渦輪機入口壓力之任何變化都會影響生產氣態氮產物之壓力。根據本發明之方法在單塔氮生產器或雙塔氮生產器同樣可適用。在單塔氮生產器之實例中，氮和氧之液體混合物流較佳自塔底，或更佳單精餾塔之中間質量交換區域抽出、予以減壓、與單精餾塔所分離之冷凝氮熱交換並由其蒸發、及所得蒸氣流在再循環壓縮機中再壓縮且較佳回送至單精餾塔之底部質量交換區域。回送之再壓縮蒸氣可與加至單精餾塔供分離之空氣混合，但這並非較佳。在雙塔氮生產器之實例中，在第二膨脹渦輪機之氣流係 554160(3) The 717 410 nitrogen generator is by no means a pure producer of liquid nitrogen, which actually consumes liquid nitrogen. An object of the present invention is to provide a method for producing a nitrogen product (and a nitrogen generator used therefor) under high pressure, which can simultaneously produce a liquid nitrogen product without sacrificing nitrogen recovery. According to the present invention, the supplier is a method for producing nitrogen, wherein compressed air is fractionated under high pressure to produce a product nitrogen nitrogen fraction and a product oxygen-rich liquid fraction containing less than 80 mol% oxygen; gaseous The nitrogen product is taken under high pressure from the gaseous nitrogen product fraction; the product oxygen-rich liquid fraction stream is evaporated by indirect heat exchange with the condensed nitrogen separated by the fractionation; Gaseous nitrogen products are produced simultaneously; and the refrigeration of the method is (i) the compressed air stream is expanded in a first expansion turbine to perform external work, and (ii) the vaporized product oxygen-rich fraction stream is at least partially in a second expansion turbine Generated by external expansion and performing external work, characterized in that the compressed air flow enters the first expansion full turbine at a pressure substantially exceeding the pressure of obtaining gaseous nitrogen products, but leaves the first expansion turbine under the pressure of substantially gaseous nitrogen products, and At least a portion of the air separated in the fractionation column is supplied by a first expansion turbine. The present invention also provides a nitrogen producer implementing the above method, comprising: a fractionation column which can be operated to produce high-pressure gaseous nitrogen products and oxygen-enriched air products containing less than 80 mole% oxygen, and the nitrogen producer can also produce simultaneously Liquid nitrogen products; a first expansion turbine for expanding the first compressed air stream and performing external work; a nitrogen condenser for condensing by indirect heat exchange with the vaporized product oxygen-enriched liquid air stream Nitrogen separated by the fractionation tower; and a 554160 (4) two-expansion turbine, which is used to expand the vaporized product oxygen-enriched air and perform external work, especially the outlet of the first expansion turbine is in communication with the fractionation tower. The first expansion turbine is arranged to be discharged to a fractionation column, which can produce liquid nitrogen products up to at least 10% without sacrificing the nitrogen recovery of the method of the present invention and the nitrogen generator. Another important advantage of the method and the nitrogen generator of the present invention is that the amount of refrigeration produced and thus the amount of liquid nitrogen product produced simultaneously with the high-pressure gaseous nitrogen product can be changed by adjusting the air pressure flowing into the inlet of the first expansion turbine. This adjustment can be easily carried out without changing the outlet pressure of the first turbine, and therefore does not change the pressure for producing high-pressure gaseous nitrogen products. Such facilities did not exist in previous nitrogen producers that used only single expansion turbines, as there were no facilities to adjust their inlet pressure without substantially affecting other operating parameters of the producer. Similarly, the nitrogen producer according to EP-A-0 932 004 links the inlet pressure of its air expansion turbine with the operating pressure of its fractionation tower, so any change in the inlet pressure of the air expansion turbine will affect the production of gaseous nitrogen products. The pressure. The method according to the invention is equally applicable to a single-tower nitrogen producer or a double-tower nitrogen producer. In the case of a single column nitrogen producer, the liquid mixture of nitrogen and oxygen is preferably withdrawn from the bottom of the column, or a better intermediate distillation zone of a single distillation column, decompressed, and condensed from the single distillation column. The nitrogen is heat exchanged and evaporated therefrom, and the resulting vapor stream is recompressed in a recirculation compressor and preferably returned to the bottom mass exchange area of the single rectification column. The returned recompressed vapor may be mixed with air added to a single distillation column for separation, but this is not preferred. In the example of a two-column nitrogen producer, the air flow in the second expansion turbine is 554160.

(5) 藉與低壓分餾塔已分離之冷凝氮熱交換而蒸發。在雙塔氮生產器之實例中，全部的高壓氣態氮產物較佳取自高壓塔。為便利獲得高壓氣態氮產物，低壓精餾塔所分離之液體氮較佳泵送至高壓精餾塔。這可幫助增加高壓精餾塔中之液體氮回流，並減少對置於高壓塔頂部、與低壓塔底部成熱交換關係以製造此種回流之冷凝器之依賴. 欲在精餾塔分離之氣態空氣較佳至少8 5體積％係自第一膨脹渦輪機流入分餾塔中。也可將分開的液化空氣流引入分餾塔中。再一可能性是不需要將液體空氣分開引入餾塔中，而是安排操作根據本發明之方法，使得離開第一膨脹渦輪機的氣流及/或氧和氮之混合物之再壓縮流在小量液體空氣之存在下進入分餾塔中。離開第一膨脹渦輪機之空氣流較佳與高壓產物氮流及與富氧空氣產物流在其加入分餾塔之上游熱交換而冷卻。離開第二膨脹渦輪機之產物富氧空氣流較佳與流入第一膨脹滿輪機之壓縮空氣流熱交換而加熱。本專利富、氧空氣流通常係以廢氣流排放至大氣中。”產物”一詞，如此處所用，涵蓋廢氣流。如有需要，根據本發明之方法及氮生產器可生產含有少於1 ppb氧雜質之氣態氮產物。根據本發明之方法及氮生產器現將參照隨附圖式作更進一步解說，圖式中：圖1係根據本發明之單分餾塔氮生產器之製程流程圖，及 -10- 554160(5) Evaporation by heat exchange with the condensed nitrogen that has been separated from the low-pressure fractionation column. In the example of a two-column nitrogen producer, the entire high-pressure gaseous nitrogen product is preferably taken from a high-pressure column. In order to facilitate obtaining high-pressure gaseous nitrogen products, the liquid nitrogen separated by the low-pressure rectification column is preferably pumped to the high-pressure rectification column. This can help increase the liquid nitrogen reflux in the high-pressure rectification column and reduce the reliance on the condenser placed on top of the high-pressure column and in heat exchange relationship with the bottom of the low-pressure column to make such a reflux. Preferably, at least 85 vol% of the air flows from the first expansion turbine into the fractionation column. A separate stream of liquefied air can also be introduced into the fractionation column. A further possibility is that the liquid air does not need to be introduced separately into the distillation column, but the method according to the invention is arranged to operate so that the gas stream leaving the first expansion turbine and / or the recompressed stream of the oxygen and nitrogen mixture is in a small amount In the presence of air, it enters the fractionation column. The air stream leaving the first expansion turbine is preferably cooled by heat exchange with the high pressure product nitrogen stream and with the oxygen-enriched air product stream upstream of its addition to the fractionation column. The product oxygen-enriched air stream leaving the second expansion turbine is preferably heated by heat exchange with the compressed air stream flowing into the first expansion full turbine. The patent-enriched, oxygen-enriched air stream is typically emitted into the atmosphere as an exhaust stream. The term "product", as used herein, covers exhaust gas streams. If desired, the method and nitrogen generator according to the present invention can produce gaseous nitrogen products containing less than 1 ppb of oxygen impurities. The method and nitrogen generator according to the present invention will now be further explained with reference to the accompanying drawings, in which: FIG. 1 is a process flow chart of the nitrogen generator of a single fractionation tower according to the present invention, and -10- 554160

⑹ 圖2係根據本發明之雙分餾塔氮生產器之概略流程圖。附圖均未按照比例。請參閱圖1，空氣係在壓縮機1 〇 2中壓縮。壓縮機1 〇 2有眾多壓縮段（未示出）且附有内冷卻器（未示出）以便在空氣由一壓縮段流至下一段時自空氣移除壓縮熱。所得壓縮空氣流經後冷卻器1 〇 4以除去壓縮機i 〇 2最後段加諸於空氣之壓縮熱。所得空氣由後冷卻器1 04以溫度約等於或略馨低於周圍溫度流至純化裝置106。純化裝置1〇6之主要目的是自空氣移除實質上全部的水蒸氣及二氧化碳雜質，同時也移除氫及一氧化碳雜質。水蒸氣及二氧化碳雜質之移除會因吸附而不完全。壓力轉換及溫度轉換空氣純化方法二音都已為本技藝所熟知，此處不必贅述。氫及一氧化碳雜質町根據ΕΡ-Α-0 43 8 2 82之方法（其併於此以供參考）催化，移除。所得純化之壓縮空氣流係流至主熱交換器1 08。純化2氣流係經主熱交換器熱端i丨〇進入主熱交換器。其在通過主熱交換器1〇8時被冷卻。約90%之空氣係 _自主熱交換器之中間區域抽出，並流至第一膨脹渦輪機或膨腋满輪機1 1 4 ’在其中膨脹並進行外功至所選溫度或壓力。所選溫度係冷凍溫度，在此溫度之上空氣會被分餾分離。所得膨服之空氣流再引入熱交換器1〇8並在其中進一少冷卻。進一步冷卻之膨脹空氣流自主熱交換器之冷端 1 i 2抽出並不必進行任何進一步膨脹或壓縮即引入分餾或精餾塔1 1 6之中間質量交換區域。泮取自主熱交換器1〇8、供第一渦輪膨脹機114膨脹之該 554160⑹ FIG. 2 is a schematic flow chart of a nitrogen generator of a double fractionation column according to the present invention. The drawings are not to scale. Referring to FIG. 1, the air is compressed in a compressor 102. Compressor 102 has a number of compression sections (not shown) and an internal cooler (not shown) to remove the heat of compression from the air as it flows from one compression section to the next. The resulting compressed air was passed through an aftercooler 104 to remove the heat of compression applied to the air in the last stage of the compressor 102. The resulting air flows from the aftercooler 104 to the purification unit 106 at a temperature approximately equal to or slightly lower than the ambient temperature. The main purpose of the purification unit 106 is to remove substantially all of the water vapor and carbon dioxide impurities from the air, and also to remove hydrogen and carbon monoxide impurities. Removal of water vapor and carbon dioxide impurities may be incomplete due to adsorption. Both pressure conversion and temperature conversion air purification methods are well known in the art and need not be repeated here. The hydrogen and carbon monoxide impurities were catalyzed and removed in accordance with the method of EP-A-0 43 8 2 82 (which is also incorporated herein by reference). The resulting purified compressed air stream flows to the main heat exchanger 108. The purified 2 gas stream enters the main heat exchanger through the hot end of the main heat exchanger. It is cooled as it passes through the main heat exchanger 108. About 90% of the air is taken out from the middle area of the autonomous heat exchanger, and flows to the first expansion turbine or the expansion turbine 1 1 4 ′, where it expands and performs external work to the selected temperature or pressure. The selected temperature is the freezing temperature above which the air is separated by fractionation. The resulting expanded air stream is reintroduced into the heat exchanger 108 and cooled a little in it. The further cooled expanded air flow is withdrawn from the cold end 1 i 2 of the main heat exchanger and is not introduced into the intermediate mass exchange zone of the fractionation or rectification column 1 16 without any further expansion or compression. Take the autonomous heat exchanger 108 and the 554160 for the expansion of the first turboexpander 114

⑺ 純化空氣流部份則繼續通過主熱交換器，自其山 ^ " 2流 «。此剩餘空氣流較佳自主熱交換器1 〇 8之冷端1 ^ Α 2以液態成出。所得液體空氣流通過膨脹或節流閥丨丨8， gp 、運而膨服至分餾塔1 1 6之操作溫度下。其係在與來自第一碼輪膨服機114之空氣相同之高度或以上之高度引入塔li6中。空氣係在分餾塔1 1 6中分離成塔底產物富氧液體、系i刀（通韦含有約45至60莫耳％氧）及塔頂產物氣態氮餘份。八 _餘塔1 1 6裝有供上升蒸氣與下降液體間進行緊密刀 "、牧觸〈液氣接觸裝置（未示出）。通常這些裝置都採取結構填充、毛式。富氧液體餾份流係通過分餾塔n 6底部之部份 The purified air stream continues to pass through the main heat exchanger from its mountain ^ " 2 streams «. This residual air flow is preferably formed by the cold end 1 ^ Α 2 of the autonomous heat exchanger 108 in a liquid state. The resulting liquid air stream is expanded to the operating temperature of the fractionation column 1 1 6 through an expansion or throttling valve 8, gp. It is introduced into the tower li6 at the same height or above as the air from the first code wheel expander 114. The air system is separated into the bottom product oxygen-rich liquid in the fractionation column 1 16, the system knife (Tongwei contains about 45 to 60 mole% oxygen) and the gaseous nitrogen balance of the top product. Eight _Yu Tower 1 1 6 is equipped with a tight knife between the rising vapor and the descending liquid ", Maki touch <liquid gas contact device (not shown). These devices are usually structurally filled and wool-type. The oxygen-rich liquid fraction stream passes through the bottom of the fractionation column n 6

抽口 1 2 Q 出。富氧液體空氣流在熱交換器丨22中過冷卻。叱~ 冷卻舍^、、、丨所得過田乳液體2氣流再通過節流或膨脹閥1 2 4膨脹。, 膨脹舍备、士祕、γ 、 °所得田乳硬m空氣泥通至與分餾塔i丨6相連之第— :126。膨眩—"、A 令凝器息服昌乳液體空氣流提供第一冷凝器i 26 該冷趑取„ 吓而冷卻，凝器係用以冷凝分餾塔丨16中分離之一部份泰份。μ 氧感氮餉 • 斤件液體氮之一部份回送到分餾塔u 6之頂流。舍^ '、巧作為回 >畐氣液a豆空氣流在第一冷凝器1 2 6中至少部份蒸發 ^件至少部份蒸發之氣流經由主熱交換器1 0 8之冷端j j 2 中入王熱X換器。蒸發之富氧液體空氣流則在主熱交換器二、並自其中間區域抽出。加熱之富氧空氣流在第二膨服）尚 ku . 機或滿輪膨脹機1 2 8膨脹進行外功。富氧空氣流在约主# 上 …、又換器108之冷端溫度及略高於大氣壓力下離開渦輪膨脹— 錢128。此氣流回送通過主熱交換器ι〇8之冷端η2 至熱姓1 、11 0。在離開熱端11 0時，其會排放至大氣中，但在 -12- 554160 ⑻ 此卻稱為π產物f’，因為它是自氮生產器排出。自分餾塔11 6 底部通過出口 1 2 0排出之富氧液體空氣流提供分餾塔頂部氮冷凝所需之一部份冷卻。第二液體空氣流係自精餾塔 11 6所選區域通過出口 1 3 0抽出。出口 1 3 0之位置係經選擇，使得自其抽出之液體空氣流具有較正常大氣空氣為高之氧莫耳分率但較自出口 1 2 0抽出之富氧液體空氣流為低之氧莫耳分率。自出口 130抽出之液流通過熱交換器122過冷 φ卻。過冷卻液體空氣流經由另一膨脹或節流閥1 32膨脹而減壓。如此膨脹之液體空氣流用於提供與分餾塔1 1 6頂部相連之第二冷凝器134所需之冷卻。在分餾塔分離之另外氮蒸氣因而在第二冷凝器134中冷凝，而其一部份回送至分餾塔1 1 6頂部作為回流。一部份之液體氮冷凝物經由出口 136抽出，收集為液體氮產物。液體空氣流在第二冷凝器1 3 4中蒸發，而所得氣流流至冷壓縮機1 3 8，在此再壓縮至分餾塔1 1 6之操作壓力。所得壓縮氣流在主熱交換器1 0 8 之中間區域引入主熱交換器中，並在其中冷卻至適合分餾 ®塔1 1 6分離之溫度。所得冷卻再壓縮空氣流自主熱交換器 108之冷端112流出，並經由位於分餾塔116底部區域之出口 140回送至分餾塔116。氣態氮產物流由分餾塔1 1 6頂部抽出，並沿導管1 42流過熱交換器122及主熱交換器108冷端112至熱端110(從而提供熱交換器108及122之冷卻）。所得加熱氮流可取自主熱交換器1 0 8熱端1 1 0作為產物氣態氮流。此氮產物及取自產物氮出口 1 3 6之液體氮產物之純度均視理論盤之數量而因 -13 - 554160Outlet 1 2 Q out. The oxygen-enriched liquid air stream is subcooled in the heat exchanger 22.叱 ~ Cooling chamber ^ ,,, 丨 The obtained emulsion emulsion 2 gas flow is then expanded through a throttle or expansion valve 1 2 4. , Expansion equipment, secretary, γ, ° The field milk hard m air sludge is passed to the — — 126 connected to the fractionation tower i 丨 6. Dizziness— ", A makes the condenser to take the air flow of the emulsion to provide the first condenser i 26, which is cold and cold, and the condenser is used to condense a part of the fractionation tower. 16 Part. Μ Oxygen-sensitive nitrogen • One part of the liquid nitrogen is sent back to the top stream of the fractionation column u 6. She ^ ', Qiao as return > 畐 gas liquid a bean air flow in the first condenser 1 2 6 At least part of the evaporated air flow is at least partially evaporated through the cold end jj 2 of the main heat exchanger 108 into the King Heat X converter. The vaporized oxygen-enriched liquid air flow is Draw out from the middle area. The heated oxygen-enriched air flow is in the second expansion.) The machine or full-wheel expander 1 2 8 expands for external work. The oxygen-enriched air flow is on the main #. The temperature of the cold end leaves the turbine expansion at a pressure slightly higher than atmospheric pressure—Qian 128. This air stream passes back through the cold end η2 of the main heat exchanger ι08 to the hot surname 1 and 110. When it leaves the hot end 110, it will Emission to the atmosphere, but at -12-554160 ⑻ This is called π product f 'because it is discharged from the nitrogen generator. Since the bottom of the fractionation column 11 6 is The oxygen-enriched liquid air stream discharged from the outlet 1 2 0 provides part of the cooling required for nitrogen condensation at the top of the fractionation tower. The second liquid air stream is extracted from the selected area of the distillation column 116 through the outlet 1 3 0. The outlet 1 3 The position of 0 is selected so that the liquid air stream drawn from it has a higher oxygen mole fraction than normal atmospheric air but a lower oxygen mole fraction than the oxygen-enriched liquid air stream drawn from the outlet 120. The liquid stream drawn from the outlet 130 is subcooled through the heat exchanger 122. The supercooled liquid air stream is expanded and decompressed through another expansion or throttle valve 1 32. The thus expanded liquid air stream is used to provide and fractionate the column 1 1 6 The cooling required for the second condenser 134 connected to the top. The other nitrogen vapor separated in the fractionation column is condensed in the second condenser 134, and a part of it is returned to the top of the fractionation column 1 1 6 for reflux. A portion of the liquid nitrogen condensate is extracted through the outlet 136 and collected as a liquid nitrogen product. The liquid air stream is evaporated in a second condenser 1 3 4 and the resulting gas stream flows to a cold compressor 1 3 8 where it is compressed again to a fractionation column 1 1 6 operating pressure. The resulting compressed air stream is introduced into the main heat exchanger in the middle region of the main heat exchanger 108, and is cooled therein to a temperature suitable for the separation of the fractionation column 1 1 6. The resulting cooled and compressed air stream is cooled by the main heat exchanger 108 The end 112 flows out and is returned to the fractionation column 116 through an outlet 140 located in the bottom area of the fractionation column 116. The gaseous nitrogen product stream is withdrawn from the top of the fractionation column 1 1 6 and flows through the heat exchanger 122 and the main heat exchanger 108 along the conduit 14 Cold end 112 to hot end 110 (thus providing cooling for heat exchangers 108 and 122). The obtained heated nitrogen stream can be taken as the product gaseous nitrogen stream from the hot end 108 of the main heat exchanger 108. The purity of this nitrogen product and the liquid nitrogen product taken from the product nitrogen outlet 1 3 6 depends on the number of theoretical plates and is -13-554160.

(9) 此分餾塔1 1 6内填充之實際高度而定。若需要極高純度之氮，則可提供充足理論盤數以碓保氮產物含有不到1體積 ppb 氧 ° 圖1所示裝置係擬用於連續操作。分餾塔Π 6之頂部係在實質恆定壓力下操作，通常為約1 1巴。同樣地，第一冷凝器126之蒸發側之蒸發壓力（以及第二冷凝器134之蒸發側之蒸發壓力）係實質恆定，提供第二渦輪膨脹機1 2 8恆定入 φ 口壓力，通常為約5巴。因此，第二渦輪膨脹機128產生每單位時間恆定量之冷凍。本發明方法所需每單位時間總冷柬量端視所生產液態氮產物之比例而定。比例愈高，冷束量需愈高。本發明方法之一優點為實質上相同之工廠設計可用以生產不同比例之液態產物。此一彈性可藉由第一渦輪膨脹機114之入口壓力可設定而實質不影響本發明方法 : 其他參數的這一事實獲得。在其中例如1 0%氮產物係以液態生產之典型實例中，第一渦輪膨脹機1 1 4入口壓力可為約1 6巴。因此，主空氣壓縮機1 02係配置成可將進料空氣 ®壓縮至略高於1 6巴。本發明方法之又一優點為圖1所示裝置可輕易調整以改變所生產液體氮產物之比例。這可藉由改變空氣壓縮機進料空氣之壓力而因此第一渦輪膨脹機 114之入口壓力而進行。為此，主空氣壓縮機102可具有可調整導葉（未示出）及第一渦輪膨脹機114可具有可調整入口噴嘴（未示出）。因此，所生產的液體氮產物之比例愈低，壓縮進料空氣的壓力愈低。事實上，如有需要，甚至可將氮生產器安排成不生產液體氮。在此情形時，可不經過 -14- 554160(9) The actual height of the filling in this fractionation column 1 1 6 depends on. If very high-purity nitrogen is required, sufficient theoretical disks can be provided so that the nitrogen-preserving product contains less than 1 volume ppb of oxygen ° The device shown in Figure 1 is intended for continuous operation. The top of the fractionation column Π 6 is operated at a substantially constant pressure, usually about 11 bar. Similarly, the evaporation pressure on the evaporation side of the first condenser 126 (and the evaporation pressure on the evaporation side of the second condenser 134) is substantially constant, and the second turbo expander 1 2 8 is provided with a constant inlet φ port pressure, usually about 5 bar. Therefore, the second turboexpander 128 generates a constant amount of refrigeration per unit time. The amount of total cooling required per unit time of the method of the present invention depends on the proportion of liquid nitrogen products produced. The higher the ratio, the higher the amount of cold beam needed. One advantage of the method of the present invention is that substantially the same plant design can be used to produce liquid products in different proportions. This elasticity can be obtained by the fact that the inlet pressure of the first scroll expander 114 can be set without substantially affecting the method of the present invention: other parameters. In a typical example where, for example, 10% of the nitrogen product is produced in a liquid state, the inlet pressure of the first turboexpander 114 may be about 16 bar. Therefore, the main air compressor 102 is configured to compress the feed air ® to just over 16 bar. Another advantage of the method of the present invention is that the device shown in Figure 1 can be easily adjusted to change the ratio of liquid nitrogen products produced. This can be done by changing the pressure of the feed air of the air compressor and therefore the inlet pressure of the first turboexpander 114. To this end, the main air compressor 102 may have an adjustable guide vane (not shown) and the first turboexpander 114 may have an adjustable inlet nozzle (not shown). Therefore, the lower the proportion of liquid nitrogen product produced, the lower the pressure of the compressed feed air. In fact, the nitrogen generator can even be arranged to not produce liquid nitrogen if required. In this case, it is not necessary to pass -14- 554160

(ίο) 第一渦輪膨脹機1 1 4，且壓縮進料空氣的壓力降至略高於分餾塔1 1 6所要壓力。液體氮產物之比例能調高及調低（通常在總氮產物之〇至1 〇%範圍内）的優點為一項重要的優點，因其能使工廠操作員根據需求設定液體氮產量而因此能在一段時間内開發液體氮產物之市場，而不必在市場開發時不經濟地操作工廠。圖1所示氮生產器可作各種改變、改正及添加。這些之 φ中有些將詳述於下。一種可能的修正為在眾多相互分開之壓縮機中壓縮進料空氣。若使用眾多壓縮機，則可在壓縮機中間的位置進行空氣之預純化，雖然這種作法並不佳。可作之另一種修正是省略膨脹或節流閥1 1 8及其與分餾塔 1 1 6相連之入口，及使全部純化之空氣流過第一渦輪膨脹機114。由於需在進入分餾塔116之液體與自其流出之液體：之間維持平衡，氮生產器係經配置使得自第一渦輪膨脹機 1 1 4流出之膨脹空氣流及/或自壓縮機1 3 8流出之再循環空氣流都在彼等進入分餾塔1 1 6之入***有小量液體。此種配置具有便利以液態生產之氮產物比例調整之優點。雖然第一渦輪膨脹機1 1 4及第二渦輪膨脹機1 2 8所進行之外功可僅為能量通過制動機制消失而已，但較佳自這些機器回收有用之功。因此，第二渦輪膨脹機128可連接至發電機（未示出）或可用於驅動再循環壓縮機138。因此，第二渦輪膨脹機128之轉子可裝在與壓縮機138之轉子相同的軸（未示出）上。一般而言，通常會發現自第一冷凝器 1 2 6流出之富氧空氣流之膨脹可產生較驅動壓縮機1 3 8所 -15 - 554160 00 需為多之功。在此種情沉下，可用二個相互平行之此種機器取代圖1所示第二渦輪膨脹機1 2 8。機器之一可接收冷凝器126流出之該部份富氧空氣，其膨脹正好可提供驅動壓縮機138所需之功量，而另一機器可接收過量富氧空氣，其通常係連接至發電機（未示出）。圖1所示工廠可作之另一修正為第一冷凝器126與第二冷凝器1 3 4可合併成一個單元。圖1所示工廠之另一特點為冷凝器126與134之一部份冷凍係由分餾塔中間區域經由出口 1 3 0所取得之液體空氣流所提供。因此，該氣流具有較自分餾塔116底部出口 120 抽出之富氧液體空氣流為低之氧莫耳分率。因此，該氣流在冷凝器134中可以較自底部出口 120抽出之液流在第一冷凝器126中使用之壓力為高之壓力使用。這依次具有以下結果··即必須在再循環壓縮機1 3 8進行之壓縮功較來自分餾塔116底部之液流之進料為低。一般而言，若分餾塔 1 1 6頂部之壓力為約1 1巴，則回收壓縮機1 3 8入口之壓力為約7巴。當設計圖1所示工廠以選擇分餾塔116底部所收集液體餾份之成份時，有一些彈性。此液體餾份中之氧莫耳分率愈高，排至大氣之進料空氣中之氮比例愈低，而因此本發明方法之氮回收率愈高。另一方面，塔低餾份之氧莫耳分率愈高，必須進行之分離功量愈高。再者，塔底液體之氧莫耳分率愈高，冷凝塔頂氮餾份所必須使用之壓力愈高，而因此第二渦輪膨脹機1 2 8可產生的冷凍量愈低。實務上 -16- 554160(ίο) The first turboexpander 1 1 4 and the pressure of the compressed feed air dropped to slightly higher than the pressure required by the fractionation column 1 1 6. The advantage that the proportion of liquid nitrogen products can be adjusted up and down (usually in the range of 0 to 10% of total nitrogen products) is an important advantage because it allows plant operators to set the liquid nitrogen output according to their needs. The ability to develop a market for liquid nitrogen products over a period of time without having to operate the plant uneconomically during market development. Various changes, corrections and additions can be made to the nitrogen generator shown in Figure 1. Some of these φ will be detailed below. One possible modification is to compress the feed air in a number of separate compressors. If many compressors are used, pre-purification of the air can be performed in the middle of the compressor, although this is not a good practice. Another modification that can be made is to omit the expansion or throttling valve 1 18 and its inlet connected to the fractionation column 1 16 and allow the entire purified air to flow through the first turboexpander 114. Due to the need to maintain a balance between the liquid entering the fractionation column 116 and the liquid flowing from it: the nitrogen generator is configured such that the expansion air flow from the first turboexpander 1 1 4 and / or from the compressor 1 3 The exiting recirculated air streams all contain a small amount of liquid at their inlets to the fractionation columns 1 1 6. This configuration has the advantage of facilitating the adjustment of the proportion of nitrogen products produced in liquid form. Although the external work performed by the first turboexpander 1 4 and the second turboexpander 1 2 8 can only be the disappearance of energy through the braking mechanism, it is preferable to recover useful work from these machines. Accordingly, the second turboexpander 128 may be connected to a generator (not shown) or may be used to drive a recirculation compressor 138. Therefore, the rotor of the second turboexpander 128 may be mounted on the same shaft (not shown) as the rotor of the compressor 138. Generally speaking, it is generally found that the expansion of the oxygen-enriched air stream flowing from the first condenser 1 2 6 can produce more work than driving the compressor 1 3 8 -15-554 160 00. In such a situation, two such machines parallel to each other may be used instead of the second turboexpander 1 2 8 shown in FIG. 1. One of the machines can receive that portion of the oxygen-enriched air from the condenser 126, and its expansion provides just the amount of work required to drive the compressor 138, while the other machine can receive excess oxygen-enriched air, which is usually connected to a generator (Not shown). Another modification of the plant shown in Fig. 1 is that the first condenser 126 and the second condenser 134 can be combined into one unit. Another feature of the plant shown in Fig. 1 is that a part of the condensers 126 and 134 are provided by the liquid air flow obtained from the middle area of the fractionation tower through the outlet 130. Therefore, the gas stream has a lower oxygen mole fraction than the oxygen-rich liquid air stream drawn from the outlet 120 at the bottom of the fractionation column 116. Therefore, the airflow in the condenser 134 can be used at a higher pressure than the liquid flow drawn from the bottom outlet 120 in the first condenser 126. This, in turn, has the following result. That is, the compression work that must be performed in the recirculating compressor 138 is lower than the feed of the liquid stream from the bottom of the fractionation column 116. In general, if the pressure at the top of the fractionation column 1 1 6 is about 11 bar, the pressure at the inlet of the recovery compressor 1 38 is about 7 bar. When designing the plant shown in FIG. 1 to select the components of the liquid fraction collected at the bottom of the fractionation column 116, there is some flexibility. The higher the oxygen mole fraction in this liquid fraction, the lower the nitrogen proportion in the feed air discharged to the atmosphere, and therefore the higher the nitrogen recovery rate of the method of the present invention. On the other hand, the higher the oxygen mole fraction of the lower fraction of the column, the higher the amount of separation work that must be performed. Furthermore, the higher the oxygen mole fraction of the bottom liquid, the higher the pressure that must be used to condense the nitrogen fraction at the top of the tower, and therefore the lower the amount of refrigeration that the second turboexpander 1 2 8 can produce. In practice -16- 554160

(12) ’若塔底餾份含有介於40與50體積％之氧量，即可在這些衝突標準間取得合理折衷。這即相等氮之回收率在 61_74%範圍内，若10%之氮產物以液態生產及其餘為n 巴 < 氣體時。空氣壓縮機所需之空氣壓力可在17-25巴之間邊化以生產以上產物混合物，視所選製程條件而定。所生產每單位氮之總能量消耗為約〇·23 kwh/Nm3，且不論所選方法為向空氣壓力/高回收率，或低空氣壓力/低回收鲁率’都保持接近此值。所生產為液體之產物之比例可藉由 &同芝氣進入恩力而提高至少至2 〇 %以便提高渦輪機之冷凍能力。現請參閱圖2，其所示為根據本發明之雙塔氮生產器。此一氮生產器所用的冷凍系統與圖1所示單塔氮生產器者類似。以下說明將更集中於雙塔氮生產器之特點；圖i所不早塔氮生產器並無類似特點。再凊參閱圖2,空氣係在壓縮機2〇2中壓縮、在後冷卻204 _中冷卻及在純化裝置206中純化。純化空氣由純化裝置206 流入主熱交換器208,在主熱交換器2〇8之熱端210進入主熱交換器。大部份空氣由主熱交換器2〇8之中間區威抽出並在第一膨脹渦輪機或渦輪膨脹機2丨4膨脹並進行外功。所得膨脹2氣流再引入主熱交換器2 〇 8作進一步冷卻炎冷卻至適合精餾分離之溫度。膨脹空氣流自主熱交換器208 之冷端212流出並經由底部入口 216引入雙精餾塔218。雙精餾塔218包含高壓精餾塔22〇、低壓精餾塔222及冷凝器-再沸器224，其將高壓精餾塔22〇之頂部與低壓精餾塔222 -17- 554160(12) 'If the bottoms fraction contains an oxygen amount between 40 and 50% by volume, a reasonable compromise can be achieved between these conflicting standards. This means that the recovery rate of equivalent nitrogen is in the range of 61-74%, if 10% of the nitrogen product is produced in liquid state and the rest is n bar < gas. The air pressure required by the air compressor can be margined between 17-25 bar to produce the above product mixture, depending on the selected process conditions. The total energy consumption per unit of nitrogen produced is approximately 0.23 kwh / Nm3, and it remains close to this value regardless of the method selected for air pressure / high recovery, or low air pressure / low recovery. The proportion of the product produced as a liquid can be increased by at least 20% by & Tongzhi gas entering Enli in order to increase the refrigeration capacity of the turbine. Reference is now made to Fig. 2, which shows a two-column nitrogen producer according to the present invention. The refrigeration system used in this nitrogen generator is similar to the one-column nitrogen generator shown in FIG. The following description will focus more on the characteristics of the two-column nitrogen producer; the earlier column nitrogen producer shown in Figure i does not have similar characteristics. Referring again to FIG. 2, the air is compressed in a compressor 202, cooled in a post-cooling 204 _ and purified in a purification device 206. The purified air flows into the main heat exchanger 208 from the purification device 206, and enters the main heat exchanger at the hot end 210 of the main heat exchanger 208. Most of the air is extracted from the middle zone of the main heat exchanger 2008 and is expanded in the first expansion turbine or turboexpander 2 丨 4 and performs external work. The resulting expanded 2 gas stream is reintroduced into the main heat exchanger 2008 for further cooling and cooling to a temperature suitable for rectification separation. The expanded air flow exits the cold end 212 of the main heat exchanger 208 and is introduced into the double rectification column 218 via the bottom inlet 216. The double rectification column 218 includes a high-pressure rectification column 220, a low-pressure rectification column 222, and a condenser-reboiler 224, which connects the top of the high-pressure rectification column 22 and the low-pressure rectification column 222-17 to 554160.

(13) 之底部熱連接。底部入口 216與高壓精餾塔220之底部相通。經由底部入口 216引入高壓精餾塔220之空氣在其中分離成為塔頂產物氮氣餾份及塔底富氧液體空氣餾份。塔底餘份通常含有35至40莫耳％氧。高壓精餾塔220含有液-氣接觸裝置以便在上升蒸氣與下降液體間進行質量交換。一般而T ’該等裝置包含結構填充。高壓精餾塔220所獲得之塔底富氧液體餾份係用作為低 _壓精餾塔222之進料《塔底餾份流係經由出口 226抽出、在熱交換器2 2 8中過冷卻、通過膨脹或節流閥2 3 0及引入低壓精餾塔222之中間質量交換區域。低壓精餾塔222之第二進料流係由不流至第一渦輪膨脹機2 1 4之純化空氣之部份提供。此一殘留純化空氣自主熱交換器2 0 8由其冷端2 1 2流出、通過熱交換器228過冷卻、通過膨脹或節流閥23 2膨脹及引入低壓精餾塔222之中間質量交換區域。空氣係在低壓精餾塔分離成為通常含有約50%體積氧 0之塔底產物富氧液體空氣餾份及塔頂氮蒸氣餾份。上升蒸氣與下降液體係在塔222中藉由液-氣接觸裝置（未示出）如結構填充緊密接觸。蒸氣在塔2 2 2中之向上流動係由操作冷凝器-再沸器224使塔222底部所收集之液體餾份再沸而產生。再沸係由液體與高壓精餾塔220所分離氮蒸氣之間接熱交換而進行.。此一蒸氣因此在冷凝器·再沸器224 中冷凝，所得冷凝物用作為高壓精餾塔2 2 0之回流。低壓精餾塔2 2 2所分離之氮餾份在冷凝器2 3 3中冷凝。冷凝器 2 3 3之冷凝係藉低壓精餾塔2 2 2所形成之塔底富氧液體空 -18- (14) 554160(13) Thermal connection at the bottom. The bottom inlet 216 communicates with the bottom of the high-pressure rectification column 220. The air introduced into the high-pressure rectification column 220 via the bottom inlet 216 is separated therein into a nitrogen product at the top of the column and an oxygen-rich liquid air fraction at the bottom of the column. The bottom of the column usually contains 35 to 40 mole% oxygen. The high-pressure rectification column 220 contains liquid-gas contacting means for mass exchange between the ascending vapor and the descending liquid. Generally, T ' such devices include structural packing. The bottom oxygen-rich liquid fraction obtained from the high-pressure rectification column 220 is used as the feed for the low-pressure rectification column 222. The bottoms fraction stream is withdrawn through the outlet 226 and supercooled in the heat exchanger 2 2 8 Through the expansion or throttle valve 230 and the intermediate mass exchange area introduced into the low pressure rectification column 222. The second feed stream of the low pressure rectification column 222 is provided by a portion of the purified air which does not flow to the first turboexpander 2 1 4. This residual purified air from the autonomous heat exchanger 2 0 8 flows out from its cold end 2 1 2, is subcooled through the heat exchanger 228, is expanded through the expansion or throttle valve 23 2, and is introduced into the intermediate mass exchange area of the low pressure rectification column 222. . The air is separated in a low-pressure rectification column into an oxygen-rich liquid air fraction and a nitrogen vapor fraction at the top of the column, which generally contain about 50% oxygen by volume. The ascending vapor and descending liquid systems are in close contact in column 222 by a liquid-gas contacting device (not shown) such as a structural packing. The upward flow of vapor in column 2 2 2 is generated by operating condenser-reboiler 224 to reboil the liquid fraction collected at the bottom of column 222. Reboiling is performed by indirect heat exchange between liquid and nitrogen vapor separated by high-pressure rectification column 220. This vapor is condensed in the condenser-reboiler 224, and the obtained condensate is used as the reflux of the high-pressure rectification column 220. The nitrogen fraction separated by the low-pressure rectification column 2 2 2 is condensed in a condenser 2 3 3. The condensing of condenser 2 3 3 is the oxygen-rich liquid bottom of the bottom formed by the low-pressure rectification column 2 2 2 -18- (14) 554160

氣餾份流提供。因此，此一餾份流係經由出口 2 3 4抽出並在熱交換器228過冷卻，然後通過膨脹或節流閥23 6膨脹。所得膨脹塔底餾份引入冷凝器232中並藉由與冷凝氮間接熱交換而蒸發。所得富氧空氣蒸氣經由熱交換器22 8回送藉以提供其所需之冷卻、由主熱交換器2〇8之冷端212至中間區域通過主熱交換器加熱及在以第二渦輪膨脹機23 8之功進行膨脹。所得膨脹富氧空氣經主熱交換器2〇8之冷端籲212至熱210回送。所得加熱富氧空氣流可排放至大氣中。全部氮產物較佳取自高壓精餾塔22〇。因此，蒸氣流係自高壓精餾塔220頂部透過管線24〇抽出並藉由通過主熱交換器20 8之冷端212至熱端210加熱至約周圍溫度。所得加熱氮氣流可取作為產物。此外，液體氮產物較佳取自在冷凝器-再沸器224所冷凝 ' 之氮°為此目的提供出口 242。為能自高壓精餾塔220取得-氮產物，冷凝器232所冷凝之一部份氮由泵244送通過熱交換器228之冷端至熱端並經由入口 246回送至高壓精館塔 220之中間質量交換區域。高壓精餾塔22〇在入口 246高度以上之理論盤數端視所要氮產物之純度及低壓精館塔2 2 2 所分離之氮之純度而定。在冷凝器232冷凝、不系回高壓精餾塔220之液體氮部份即用作低壓精餾塔222之回流。一般而言，在圖2所示氮生產器操作時，高壓精餾塔係在其塔頂壓力約1 1巴下及低壓精餾塔2 2 2係在其塔頂壓力約7巴下操作。第一渦輪膨脹機2 1 4之入口壓力為約丨6巴，當約1〇°/。之氮產物以液態生產時。通常第二渦輪膨脹機 •19- 554160A gaseous distillate stream is provided. Therefore, this distillate stream is withdrawn through the outlet 2 3 4 and subcooled in the heat exchanger 228, and then expanded through the expansion or throttle 23 6. The resulting bottoms of the expansion column was introduced into a condenser 232 and evaporated by indirect heat exchange with condensed nitrogen. The obtained oxygen-enriched air vapor is sent back through the heat exchanger 228 to provide its required cooling. It is heated from the cold end 212 of the main heat exchanger 208 to the middle area through the main heat exchanger and in the second turboexpander 23 The work of 8 expands. The obtained expanded oxygen-enriched air is sent back from the cold end 208 to the heat 210 of the main heat exchanger 208. The resulting heated oxygen-enriched air stream can be discharged into the atmosphere. All nitrogen products are preferably taken from the high pressure rectification column 22O. Therefore, the vapor stream is drawn from the top of the high-pressure rectification column 220 through the line 24 and is heated to about ambient temperature by passing from the cold end 212 to the hot end 210 of the main heat exchanger 20 8. The resulting heated nitrogen stream can be taken as the product. In addition, the liquid nitrogen product is preferably taken from the nitrogen condensed in the condenser-reboiler 224. An outlet 242 is provided for this purpose. In order to obtain nitrogen products from the high-pressure rectification column 220, a part of the nitrogen condensed by the condenser 232 is sent by the pump 244 through the cold end to the hot end of the heat exchanger 228 and returned to the high-pressure rectification tower 220 through the inlet 246. Intermediate mass exchange area. The theoretical number of high-pressure rectification tower 22 above the inlet 246 height depends on the purity of the desired nitrogen product and the purity of nitrogen separated in the low-pressure refinery tower 2 2 2. The liquid nitrogen portion condensed in the condenser 232 without returning to the high pressure rectification column 220 is used as the reflux of the low pressure rectification column 222. In general, when the nitrogen generator shown in Fig. 2 is operated, the high-pressure rectification column system is operated at a pressure of about 11 bar and the low-pressure rectification column 2 2 2 system is operated at a pressure of about 7 bar. The inlet pressure of the first turboexpander 2 1 4 is about 6 bar, when about 10 ° /. When the nitrogen product is produced in a liquid state. Usually second turboexpander • 19- 554160

(15) 230之入口壓力為約3巴，及出口壓力為約1.2巴。圖2所示氮生產器通常可！產高度10%之液態氮產物，在特定壓力 0.22 kWh/ Nm3下獲得70%之氮回收率。所生產為液體之產物之比例可增加至達3 0 %，若入口空氣壓力提高以提高渦輪機冷生產時。與參照圖1所說明之氮生產器類似，以液態生產之氮產物之比例可藉由改第一渦輪膨脹機2 1 4之入口壓力加以改變〇(15) The inlet pressure of 230 is about 3 bar and the outlet pressure is about 1.2 bar. The nitrogen generator shown in Figure 2 is usually available! It produces liquid nitrogen products with a height of 10% and obtains a nitrogen recovery rate of 70% at a specific pressure of 0.22 kWh / Nm3. The proportion of the product produced as a liquid can be increased up to 30% if the inlet air pressure is increased to increase the turbine cold production. Similar to the nitrogen generator described with reference to FIG. 1, the proportion of the nitrogen product produced in the liquid state can be changed by changing the inlet pressure of the first turboexpander 2 1 4.

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Claims

554160 r 第091117446號專利申請案中文申請專利範圍替換本(92年7月）拾、申請專利範圍 1. 一種生產氮之方法，其中壓縮空氣係在高壓下分餾而產生氣態氮產物餾份及含少於8 0莫耳％氧之富氧液體產物餾份；氣態氮產物係在高壓下取自氣態氮產物餾份；產物富氧液體餾份流係藉與分餾所分離之冷凝氮間接熱交換而蒸發；液體氮產物係藉冷凝分餾所分離之氮而與氣態氮產物同時生產；及方法之冷凍係由（i) 壓縮空氣流在第一膨脹渦輪機中膨脹並進行外功，及 (ii)蒸發之產物富氧餾份流至少一部份在第二膨脹渦輪機中膨脹並進行外功而產生，其特徵為該壓縮空氣流係在實質超過取得氣態氮產物壓力之壓力下進入第一膨脹渦輪機，但在實質氣態氮產物壓力下離開第一膨脹渦輪機，及在該分餾塔分離之空氣至少一部係由第一膨脹渦輪機供應。 2·如申請專利範圍第1項之方法，其中分餾係在單分餾塔中進行。 3.如申·請專利範圍第2項之方法，其中氮與氧之液體混合物流係自單塔之底部或中間質量交換區域抽出、減壓、與單塔所分離之冷凝氮熱交換及因而蒸發、及所得蒸氣流在再循環壓縮機中壓縮並回送至單塔之底部質量交換區域。 4·如申請專利範圍第1項之方法，其中分餾係在包含高壓塔及低壓塔之雙分餾塔中進行。 5·如申請專利範圍第4項之方法，其中全部氣態氮產物係 554160554160 r No. 091117446 Patent Application Chinese Patent Application Replacement (July 1992) Pick up and apply for patent scope 1. A method for producing nitrogen, in which compressed air is fractionated under high pressure to produce a gaseous nitrogen product fraction and containing Oxygen-enriched liquid product fractions with less than 80 mole% oxygen; gaseous nitrogen products are taken from gaseous nitrogen product fractions under high pressure; product oxygen-enriched liquid distillate streams are indirectly heat exchanged with condensed nitrogen separated by fractionation And evaporation; the liquid nitrogen product is produced simultaneously with the gaseous nitrogen product by condensing and separating the nitrogen; and the refrigeration of the method is (i) the compressed air stream is expanded in a first expansion turbine to perform external work, and (ii) is evaporated At least a part of the product oxygen-enriched distillate stream is expanded in a second expansion turbine and subjected to external work, and is characterized in that the compressed air stream enters the first expansion turbine at a pressure substantially exceeding the pressure of the gaseous nitrogen product obtained, but The first expansion turbine leaves the first expansion turbine under substantially gaseous nitrogen product pressure, and at least a portion of the air separated in the fractionation column is supplied by the first expansion turbine. 2. The method according to item 1 of the application, wherein the fractionation is performed in a single fractionation column. 3. The method as claimed in item 2 of the patent, wherein the liquid mixture of nitrogen and oxygen is withdrawn from the bottom of the single column or the intermediate mass exchange area, decompressed, and exchanged with the condensed nitrogen separated from the single column, and thus The evaporation and the resulting vapor stream is compressed in a recirculation compressor and returned to the bottom mass exchange area of the single column. 4. The method according to item 1 of the patent application range, wherein the fractionation is carried out in a double fractionation column comprising a high pressure column and a low pressure column. 5. The method according to item 4 of the patent application, in which all gaseous nitrogen products are 554160

取自高壓塔。 6. 如申請專利範圍第4或5項之方法，其中在低壓塔分離之液態氮係泵至高壓塔。 7. 如申請專利範圍第1至5項中任一項之方法，其中所生產液態氮產物之比例係藉改變第一膨脹渦輪機之入口壓力而改變。 8. 如申請專利範圍第1至5項中任一項之方法，其中欲藉分餾分離之氣態空氣至少8 5體積％流經第一膨脹渦輪機。 9· 一種用於進行如申請專利範圍第1項之方法之氮生產器，包含一分餾塔，其可運轉產生高壓氣態氮產物及含少於80莫耳％氧之富氧空氣產物，該氮生產器可同時生產液體氮產物；一第一膨脹渦輪機，其係用於使第一壓縮空氣流膨脹並進行外功；一氮冷凝器，其係用於與蒸發之產物富氧液態空氣流間接熱交換以冷凝分餾塔所分離之氮；及一第二膨脹渦輪機，其係用於使蒸發·之產物富氧空氣膨脹並進行外功，其特徵為第一膨脹渦輪機之出口係與分餾塔相通。 10. 如申請專利範圍第9項之氮生產器，其中分餾塔係單分餾塔。 11. 如申請專利範圍第1 0項之氮生產器，尚包含一用於冷凝氮之又一冷凝器，該又一冷凝器具有供包含取自分餾塔之氧及氮之混合物之液體流通過之通路，該通路的出口端與用於回送蒸發之混合物至分餾塔底部之再 554160Taken from the high pressure tower. 6. The method according to item 4 or 5 of the patent application scope, wherein the liquid nitrogen separated in the low pressure column is pumped to the high pressure column. 7. The method according to any one of claims 1 to 5, wherein the ratio of the liquid nitrogen product produced is changed by changing the inlet pressure of the first expansion turbine. 8. The method according to any one of claims 1 to 5, wherein at least 85 vol% of the gaseous air to be separated by fractionation flows through the first expansion turbine. 9. A nitrogen generator for carrying out the method as described in the first item of the scope of patent application, comprising a fractionation column which can be operated to produce high-pressure gaseous nitrogen products and oxygen-enriched air products containing less than 80 mole% oxygen, the nitrogen The producer can simultaneously produce liquid nitrogen products; a first expansion turbine, which is used to expand the first compressed air stream and perform external work; a nitrogen condenser, which is used to indirectly heat the evaporated oxygen-enriched liquid air stream of the product Exchange the nitrogen separated by the condensing fractionation tower; and a second expansion turbine for expanding the oxygen-enriched air of the vaporized product and performing external work, characterized in that the outlet of the first expansion turbine is in communication with the fractionation tower. 10. For example, the nitrogen generator of item 9 of the patent application scope, wherein the fractionation column is a single fractionation column. 11. For example, the nitrogen producer of the scope of patent application No. 10 further includes a further condenser for condensing nitrogen, the further condenser having a liquid stream containing a mixture of oxygen and nitrogen taken from the fractionation column. And the exit end of the passage is used for returning the evaporated mixture to the bottom of the fractionation tower.

循環壓縮機相通。 12. 如申請專利範圍第9項之氮生產器，其中分餾塔係包含高壓塔與低壓塔之雙分餾塔。 13. 如申請專利範圍第1 2項之氮生產器，尚包括用於輸送低壓塔所分離之冷凝氮至高壓塔之泵。The circulation compressors communicate. 12. The nitrogen producer of item 9 of the scope of the patent application, wherein the fractionation column system comprises a double fractionation column of a high pressure column and a low pressure column. 13. For example, the nitrogen generator of item 12 of the patent application scope also includes a pump for conveying the condensed nitrogen separated from the low pressure column to the high pressure column.

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