^26637 Λ7 --_;_____B7 五、發明説明（1 ) 經濟部中央標率局員工消費合作社印製 發明説明 本發明係有關於氨之氧化作用。氨之氧化作用廣泛地應 用於硝酸減化氫之製心於_之製造中，纟係以空氣 氧化成氧化氮，而於氰化氫之製造中，氨與甲统（通常爲天 然氣)一之混合物係以空氣氧化。於此二方法中，該氣體混合 物於高溫下通過觸媒以進料化作用。副反應如氮或一氧 化二氮之形成皆非所欲。因此除了良好之活性外，觸媒須 要有良好之選擇性。 氧化反應係放熱反應：當加熱後之氣體混合物通過觸媒 時，乳化反應即伴隨著熱量之釋進行，使得氣體混合 物與觸媒兩者之溫度上升直至達到穩態狀況爲止。反應之 選擇性取決於觸媒溫度，以及任何給定之操作條件，即氣 體成份、觸媒、觸媒壽命、流量等，—般而言有一最適溫 度。觸媒溫度可藉由一個或多個方法變數之修正加以控 制，如氣體混合物預熱之溫度及/或氨於氣體混合物中之比 例。 吾人注意到無論如何都有—顯著之溫度梯度存在於觸媒 中’因而並非所有之觸媒皆於所欲最適佳狀況下操作。此 溫度梯度郅份係由觸媒入口側之熱輻射至進入之氣體混合 物所產生。 於本發明中此輻射效應降至最低。 因此本發明提供氨之氧化作用，其包括使預熱至高溫之 氣與含氧氣體之混合物’通過至少一何有效使氛敦化之觸 媒床，其中爲使觸媒溫度更均勻，該氣體混合物將通過配 (請先閲讀背面之注意事項再填寫本頁) d 裝. -π 本紙張尺度賴悄 Λ 7 —---------------- Β7 五、發明説明（2 ) 〜----- 置Α觸媒床上游之有孔反射络，該反射器可有效將觸媒床 入口表面所輻射之熱反射回至觸媒床。 經濟部中央樣準局員工消費合作社印製 該觸媒可爲銷，視需要混合其它如錄之貴重金屬，其形 狀爲由金屬線所形成之篩狀或網狀。或者該觸媒可以爲丸 丰狀擠出物狀或細粒狀之乳化材料，如含氧化話之组合 物。例如，於CN-A-86 108 985中已建議使用氧化鑭/氧化 鈽/氧化鈷之組合物，一般式爲Lai_xCexCo03(其中X爲自0 至1 )’其藉由特定共沉殿法製備爲|氧化作用觸媒。氧化 觸媒較佳，含有至少一含鈷之混合氧化物相與至少一選自 稀土族與釔之元素A，該鈷與元素A相互相間之比例爲元 素A對姑原子比係於0.8至1,2之間，特別是1 · 0至1 2之 間。較佳使用至少一種選自釔、鋅、鑭、鈦與镨之元素作 爲元素A之一部份或全部。元素a可包括至少一種選自鈽 與錯之變償元素V v與至少一種選自釔之非變價元素v η以 及如鑭或钕之非變價稀土族元素之混合物。特定言之，變 價元素V ν對非變價元素V η之原子比例較佳係在〇至1之 間，尤其是在0至0.3之間。此類氧化觸媒，可呈其中氧 的量不是化學計量之形態。這可由鈷以及存在於元素Α作 爲一部份.或全部之任何變價稀土族元素之變價所產生。 本發明之方法中，輻射反射器係配置於觸媒上游，以反 射從觸媒入口表面所輻射之熱量回至觸媒。以此方式，觸 媒入口表面所產生之熱量散失將降至最低，因而觸媒溫度 可更加均勻。反射器較佳爲配置於觸媒上游之有孔平板。 孔洞要有足夠之數目與大小，俾反射器對氣體混合物之流 _ -5- 本紙張尺度適用fii"家標準（CNS) Λ4^~^οχ297公趋----- Λ7 426637 ________B7 _；__ 五、發明説明（3 ) 動通過只存有不顯著之阻抗，但另一方面，其必須只占反 射器之小邵份面積，俾相當量之輕射會被反射。孔洞較佳 爲百葉窗型式，俾基本上反射器之所有面積都可用於反射 輻射熱量。該反射器f可做爲擴散器之用，以確保氣體混 合物通過觸媒床時均勻分佈。反射器較佳置於觸媒床頂層 上方I至3 0公分間。 本發明將參照隨附圖示加以説明，其中圖1係氨氧化作 用反應器之截面積圖示。圖2顯另一替代佈置。 圖1顯示具有入口 2與出口 3之容器1 。配置於容器橫 向全面者係觸媒床4、5，各自由鉑/铑合金線所形成之一 疊網狀物所組成。靠近入口之床4之上游放置一由適當耐 熱金屬如印卡合金所形成之反射器平板6 。反射器平板6 中附有眾多百葉窗板7。 使用時，預熱至所要之入口溫度之氨與空氣之混合物即 送至入口 2 。該混合物通過反射器平板中之百葉窗板7 , 然後再通過觸媒床4與5。氨之氧化作用便發生並伴隨著 熱量之釋出。因此觸媒床與氣體混合物二者之溫度將增 高。然後經反應之氣體經由出口 3離開反應器。於稳態操 作下，觸媒床5與經反應之氣體之溫度基本上相同。同樣 地，觸媒床4大部份厚度之溫度與經反應之氣體混合物之 溫度相同。然而熱量易於從入口亦即觸媒床4之上部表面 經由輻射散失至進入之氣體流。此輻射熱量之相當部份將 由反射器平板6反射回至觸媒床4，因此降低觸媒床$人 口部份與觸媒床其餘部份間之溫度差距。依此方式觸媒床 -6- k張尺度適用__中國國家標準（CNS ) A4規格（210X 297公总) " — --^---；-----J 裝------訂 产 V' (請先閱讀背面之注意事項再填鲟本頁) 經濟部中央標準局負工消費合作社印製 經濟部中央標準局員工消費合作社印製 426637 Λ.7 ____________ B7 五、發明説明（4 ) " 卿度更加均勻，能使所選擇之反應條件產生最適之選擇 性。 一替代佈置示於圖2 。此處反射器係由一對金屬板§ 、 9 一在另一I上隔開所組成。各板都有孔，以便允許反應 物通過各板，但其孔洞係錯開的，故從觸媒床輻射，通過 下層板孔洞之熱量會被上層板之下表面反射回來。 於一些情形例中，可能需於反射器之上部表面即遠離觸 媒床之表面提供熱絕緣層以使反射器上部表面之熱量散 失，降至最低。 於氨氧化成氧化氮以製造硝酸中，該氧化過程可於溫度 800至1〇〇〇 C ’特別是850至950 °C及絕對壓力1至15巴 下，以氨於空氣中之濃度爲5至1 5。/。，通常約1〇%體積操 作。 選擇性將隨空間流速增加而增加，故，大於每小時 1. 5x1 〇5之高空間流速係適當的。空間流速取決定於進料氣 體之線性速度（於正常溫度壓力下），以及觸媒床之深度。 商業大氣壓氨氧化作用過程習用之線性氣體速度通常超過 每小時2000米，而一般在每小時2500米至8000米較佳.，每 小時4000米至6000米之範圍内。於較高壓力下操作之商業 製程會使用相當高之線性氣體速度，如每小時30000米至 40000米。考慮經濟原因，床厚度宜小於5 0毫米。例如以 深度2 0毫米之床而言，於線性氣體速度每小時4000米下， 空間流速爲每小時2x 1 05。 本纸張尺度適用中國國家標準（CNS ) A4規格（210X297公潑） (請先閱讀背面之注意事項蒋填爲本頁) -裝·^ 26637 Λ7 --_; _____ B7 V. Description of the invention (1) Printed by the Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs. Description of the invention The present invention relates to the oxidation of ammonia. The oxidation of ammonia is widely used in the production of nitric acid to reduce hydrogenation. In the manufacture of _, the oxidation of air to nitrogen oxide, and in the production of hydrogen cyanide, ammonia and the first system (usually natural gas) The mixture was oxidized with air. In these two methods, the gas mixture is fed through a catalyst at a high temperature. Side reactions such as the formation of nitrogen or nitrous oxide are undesirable. Therefore, in addition to good activity, the catalyst must have good selectivity. The oxidation reaction is an exothermic reaction: When the heated gas mixture passes through the catalyst, the emulsification reaction proceeds with the release of heat, so that the temperature of the gas mixture and the catalyst rises until it reaches a steady state. The selectivity of the reaction depends on the catalyst temperature and any given operating conditions, i.e. gas composition, catalyst, catalyst life, flow rate, etc.-generally an optimum temperature. The catalyst temperature can be controlled by modification of one or more method variables, such as the temperature of the gas mixture preheating and / or the ratio of ammonia in the gas mixture. I have noticed that there is anyway—a significant temperature gradient exists in the catalyst ’and therefore not all catalysts operate under the optimal conditions desired. This temperature gradient component is generated by the heat radiation from the entrance side of the catalyst to the incoming gas mixture. This radiation effect is minimized in the present invention. Therefore, the present invention provides the oxidation of ammonia, which includes passing a mixture of preheated to high temperature gas and an oxygen-containing gas through at least one catalyst bed which is effective to make the atmosphere, wherein in order to make the catalyst temperature uniform, the gas mixture Will be equipped (please read the notes on the back before filling this page) d. -Π The paper size is quietly Λ 7 —---------------- Β7 V. Description of the invention (2) ~ ----- The perforated reflection network located on the A catalyst bed can effectively reflect the heat radiated from the entrance surface of the catalyst bed back to the catalyst bed. Printed by the Consumer Cooperative of the Central Sample Bureau of the Ministry of Economic Affairs. The catalyst can be a pin, if necessary, mixed with other recorded precious metals, and its shape is a sieve or mesh formed by metal wires. Alternatively, the catalyst may be a pellet-shaped extrudate or a fine-grained emulsified material, such as a composition containing oxidized words. For example, in CN-A-86 108 985, it has been proposed to use a lanthanum oxide / rhenium oxide / cobalt oxide composition, the general formula is Lai_xCexCo03 (where X is from 0 to 1) ', which is prepared by a specific coprecipitation method as | Oxidation Catalyst. Oxidation catalysts are preferred, containing at least one cobalt-containing mixed oxide phase and at least one element A selected from the rare earths and yttrium. The ratio of the cobalt and element A to each other is that the element A to atomic ratio is 0.8 to 1 Between 2 and especially between 1 · 0 and 12. It is preferable to use at least one element selected from the group consisting of yttrium, zinc, lanthanum, titanium, and scandium as a part or all of the element A. The element a may include a mixture of at least one variable element V v selected from ytterbium and erroneous, and at least one non-valence element v η selected from yttrium, and a non-valence rare earth element such as lanthanum or neodymium. In particular, the atomic ratio of the valence element V ν to the non-valence element V η is preferably between 0 and 1, especially between 0 and 0.3. Such an oxidation catalyst may be in a form in which the amount of oxygen is not stoichiometric. This can result from the valence of cobalt and any variable valence rare earth elements present in element A as part or all. In the method of the present invention, the radiation reflector is arranged upstream of the catalyst to reflect the heat radiated from the surface of the catalyst inlet back to the catalyst. In this way, the heat dissipation from the catalyst inlet surface will be minimized, so the catalyst temperature can be more uniform. The reflector is preferably a perforated flat plate arranged upstream of the catalyst. The holes should be of sufficient number and size, and the flow of gas mixture by the 俾 reflector _ -5- This paper size applies to the Fii " House Standard (CNS) Λ4 ^ ~ ^ οχ297 public trend ----- Λ7 426637 ________B7 _; __ V. Description of the invention (3) There is only insignificant impedance in the dynamic transmission, but on the other hand, it must only occupy a small area of the reflector, and a small amount of light shot will be reflected. The holes are preferably of the shutter type, and substantially all the area of the reflector can be used to reflect radiant heat. The reflector f can be used as a diffuser to ensure a uniform distribution of the gas mixture as it passes through the catalyst bed. The reflector is preferably placed between 1 and 30 cm above the top layer of the catalyst bed. The present invention will be explained with reference to the accompanying drawings, wherein Fig. 1 is a sectional view of an ammoxidation reactor. Figure 2 shows another alternative arrangement. FIG. 1 shows a container 1 having an inlet 2 and an outlet 3. The catalyst beds 4, 5 arranged in the container's horizontal direction are each composed of a stacked network formed by platinum / rhodium alloy wires. Near the entrance bed 4 is placed a reflector plate 6 formed of a suitable heat-resistant metal such as a card alloy. A plurality of louver plates 7 are attached to the reflector plate 6. In use, a mixture of ammonia and air preheated to the desired inlet temperature is sent to the inlet 2. The mixture passes through the louver plate 7 in the reflector plate, and then through the catalyst beds 4 and 5. Oxidation of ammonia occurs with the release of heat. The temperature of both the catalyst bed and the gas mixture will therefore increase. The reacted gas then leaves the reactor via outlet 3. Under steady state operation, the temperature of the catalyst bed 5 and the reacted gas are substantially the same. Similarly, the temperature of most of the thickness of the catalyst bed 4 is the same as the temperature of the reacted gas mixture. However, heat is easily dissipated from the inlet, i.e., the upper surface of the catalyst bed 4, via radiation to the incoming gas stream. A considerable portion of this radiant heat will be reflected back to the catalyst bed 4 by the reflector plate 6, thus reducing the temperature difference between the mouth portion of the catalyst bed and the rest of the catalyst bed. In this way, the catalyst bed -6-k scales are applicable __China National Standard (CNS) A4 specification (210X 297 total) " —-^ ---; ----- J equipment ---- --Order V '(Please read the notes on the back before filling out this page) Printed by the Central Standards Bureau of the Ministry of Economic Affairs, printed by the Consumer Cooperatives of the Ministry of Economic Affairs Printed by the Central Consumers' Bureau of the Ministry of Economic Affairs, printed by the Consumer Cooperatives 426637 Λ.7 ____________ B7 Note (4) " The degree of clarity is more uniform, which can make the optimal selectivity of the selected reaction conditions. An alternative arrangement is shown in Figure 2. Here the reflector is composed of a pair of metal plates § 9, one separated on the other I. Each plate has holes to allow the reactants to pass through the plates, but the holes are staggered, so the radiation from the catalyst bed, the heat passing through the holes of the lower plate will be reflected back by the lower surface of the upper plate. In some cases, it may be necessary to provide a thermal insulation layer on the upper surface of the reflector, i.e., the surface away from the catalyst bed, to minimize heat loss from the upper surface of the reflector. In the oxidation of ammonia to produce nitric oxide to produce nitric acid, the oxidation process can be performed at a temperature of 800 to 1000 ° C, especially 850 to 950 ° C and an absolute pressure of 1 to 15 bar. To 1 5. /. , Usually about 10% volume operation. Selectivity will increase with increasing spatial velocity, so a high spatial velocity greater than 1.5 x 105 per hour is appropriate. The space velocity is determined by the linear velocity of the feed gas (at normal temperature and pressure) and the depth of the catalyst bed. The linear gas velocity commonly used in commercial atmospheric pressure ammoxidation processes usually exceeds 2000 meters per hour, and is generally preferably between 2500 meters and 8000 meters per hour, and in the range of 4000 meters to 6000 meters per hour. Commercial processes operating at higher pressures use fairly high linear gas velocities, such as 30,000 to 40,000 meters per hour. For economic reasons, the bed thickness should be less than 50 mm. For example, for a bed with a depth of 20 mm, at a linear gas velocity of 4,000 meters per hour, the space velocity is 2 x 105. This paper size applies to Chinese National Standard (CNS) A4 specification (210X297 male splash) (Please read the precautions on the back first and fill in this page)