1 Almost Describe
年代起，在分析了国际国内氨合成塔内件优缺点的基础上，独创了Ⅲ J型氨合成塔内件，取得了国家专利，是国内数种氨合成塔内件中唯一经原化工部鉴定的内件，鉴定结论是，该内件为国内首创，主要技术指标取得突破性进展，达到国际先进水平。 Hunan Anchun High-tech Co., Ltd. (hereinafter referred to as Anchun Company) since the 1980s , based on the analysis of the advantages and disadvantages of international and domestic ammonia synthesis tower internal components, the original type III J ammonia synthesis tower internal components have been obtained The national patent is the only internal part of several domestic ammonia synthesis tower internal parts that has been identified by the former Ministry of Chemical Industry. The identification conclusion is that this internal part is the first of its kind in the country, and major technical indicators have achieved breakthrough progress and reached international advanced levels. 型氨合成内件，包含3个新的国家专利技术。 Anchun company keeps innovating and making progress, and then launched III J99 ammonia synthesis internals, including 3 new national patented technologies. 型、Ⅲ J99型氨合成内件经由φ 800 、φ 1000到φ 1200 ；后又开发了Ⅲ JD2000型φ 1400 、φ 1600 、φ 1800 、φ 2000氨合成内件。 Ⅲ J and Ⅲ J99 ammonia synthesis internals pass through φ 800 , φ 1000 to φ 1200 ; later, Ⅲ JD2000 φ 1400 , φ 1600 , φ 1800 , φ 2000 ammonia synthesis internals have been developed. （φ 600塔）发展到180 kt 、 200 kt 。 The annual ammonia production capacity of a single tower has developed from 20 kt (φ 600 towers) to 180 kt and 200 kt . Ⅲ JD2000型- φ 2200氨合成塔，在技术上又有较大的提升；单塔生产能力日均达850 ～ 910 t ，受到了用户的青睐。 The Ⅲ JD2000 - φ 2200 ammonia synthesis tower developed in recent years has been greatly improved in technology; the average daily production capacity of single towers has reached 850 to 910 t , which has been favored by users.
2 型- φ 2200氨合成塔的设计思想 Ⅲ JD2000 - Design Idea of φ 2200 Ammonia Synthesis Tower
型- φ 1800 、φ 2000氨合成内件的基础上，引入新的理念，设计了 Ⅲ JD2000型- φ 2200氨合成内件 ，具体如下。 In order to realize the scale-up of single-system production capacity and further reduce energy consumption, Anchun Company introduced new concepts based on the III JD2000 -φ 1800 and φ 2000 ammonia synthesis internals and designed the III JD2000 - φ 2200 ammonia synthesis. The internals are as follows.
）充分发挥第一绝热层的作用。 ( 1 ) Give full play to the role of the first thermal insulation layer. ％～ 9 ％，即第一绝热层温升110 ～ 133 ℃。 Entering zero meters of unreacted gas has low ammonia content, is far from the reaction equilibrium, and the reaction speed is fast. Try to produce more ammonia in the first layer of the reaction, so that the first layer of ammonia has a net ammonia value of 8 % to 9 %, that is, the first The temperature of the insulation layer rises from 110 to 133 ° C. 措施如下。 The specific measures are as follows.
～ 3.1 m 。 ① Increase the height of the first insulation layer. The design height of the first insulation layer is 2.5 to 3.1 m .
② Reduce the zero-meter temperature and increase the hot spot temperature. ％），温度低（ 370 ～ 380 ℃），离反应平衡点最远；如零米温度为380 ℃，将第一绝热层反应终点温度设计为490 ～ 513 ℃，则第一绝热层的氨含量增加8 ％ ～ 9 ％（氨净值） ，即第一绝热层完成氨合成反应的50 ％。 The zero-point circulating gas entering the first insulation layer has the lowest ammonia content (approximately 2.16 %), the temperature is low ( 370 to 380 ℃), and it is farthest from the reaction equilibrium point. The end temperature of the reaction is designed to be 490 to 513 ° C, and the ammonia content of the first insulation layer will increase by 8 % to 9 % (net ammonia value) , that is, the first insulation layer will complete 50 % of the ammonia synthesis reaction.
） 第一层绝热反应后的热气体，不再采取冷激，而是用塔内换热器间接冷却后再进入第二层，这样更有利于氨合成反应温度接近最适宜温度曲线。 ( 2 ) The hot gas after the adiabatic reaction in the first layer is no longer cold-shocked, but indirectly cooled by the heat exchanger in the tower and then enters the second layer, which is more conducive to the ammonia synthesis reaction temperature approaching the optimal temperature curve.
）冷管束（段间冷却器）的气体出口设在催化剂床层表面，使进塔气体100 ％地通过第一层催化剂，有利于降低零米温度，提高氨净值。 ( 3 ) The gas outlet of the cold pipe bundle (inter-stage cooler) is set on the surface of the catalyst bed, so that the gas entering the tower passes 100 % of the first layer of catalyst, which is beneficial to reducing the temperature of zero meters and increasing the net ammonia value.
）分流气占到近50 ％，使通过中心管和换热器的气体由原来的65 ％～ 70 ％减少至50 ％，降低塔阻力。 ( 4 ) The split gas accounts for nearly 50 %, so that the gas passing through the central tube and heat exchanger is reduced from 65 % to 70 % to 50 %, and the tower resistance is reduced.
）提高出塔温度。 ( 5 ) Increase the temperature of the tower. ℃，产生3.0 ～ 4.0 MPa过热蒸汽，使回收蒸汽的利用价值更高。 The designed maximum exit temperature is 380 ℃, which produces 3.0 to 4.0 MPa superheated steam, which makes the value of recovered steam higher.
）大幅度提高出塔氨含量。 ( 6 ) The ammonia content in the tower is greatly increased.
3 型- φ 2200氨合成塔的结构特点 Ⅲ JD2000 - φ 2200 Ammonia Synthesis Structure
）塔结构为三层四段，两径一轴。 ( 1 ) The structure of the tower is three stories and four sections, with two diameters and one axis. ％～ 80 ％；第一层为轴向绝热段，为了使第一层反应温度不致超高，在第一层中部设一个冷气调温器；第二层包含径向绝热段和径向间冷段；第三层为径向绝热段。 The radial section accounts for 70 % to 80 % of the bed height. The first layer is an axial thermal insulation section. In order to prevent the reaction temperature of the first layer from becoming too high, a cold air thermostat is set in the middle of the first layer; the second layer contains Radial thermal insulation and radial cooling; the third layer is radial thermal insulation.
）冷管束的气体出口在催化剂床层表面，使进塔气体100 ％地通过第一层催化剂，提高第一层催化剂的利用率。 ( 2 ) The gas outlet of the cold tube bundle is on the surface of the catalyst bed, so that the gas entering the tower 100 % passes through the first layer of catalyst, thereby improving the utilization rate of the first layer of catalyst.
）第一层绝热反应后的热气体被塔内换热器间接冷却后再进入第二层径向绝热段和径向内冷段，这样更有利于氨合成反应温度接近最适宜温度曲线。 ( 3 ) The hot gas after the adiabatic reaction of the first layer is indirectly cooled by the heat exchanger in the tower and then enters the second layer of the adiabatic and radial internal cooling sections, which is more conducive to the ammonia synthesis reaction temperature approaching the optimal temperature curve. .
）采用分流工艺。 ( 4 ) Use the shunt process.
）结构简单，催化剂可自卸。 ( 5 ) The structure is simple and the catalyst can be unloaded.
型- φ 2200氨合成内件结构示意见图1 。 Ⅲ JD2000 -φ 2200 ammonia synthesis internal structure is shown in Figure 1 .
Figure 1 型- φ 2200 氨合成内件结构示意图 Ⅲ JD2000 - φ 2200 ammonia synthesis internal structure diagram
4 ⅢJD2000- φ2200 ammonia synthesis process
4.1 Gas flow in the tower
The gas enters the tower in two streams. 的气体直接进入冷管束（段间冷却器）。 A stream of about 45% of the gas directly enters the cold tube bundle (interstage cooler). 的冷气，由合成塔下部环隙进入，在塔顶引出；二是塔外热交换器加热的、约15%的气体。 This gas is composed of two parts: first, about 30% of the cold air coming from the oil at the outlet of the circulation machine, which enters from the lower ring gap of the synthesis tower, and is led out at the top of the tower; gas. ％）。 The two parts of gas merge at the top of the tower to introduce a cold tube bundle, and the gas from the cold tube bundle enters the surface of the catalytic bed (zero meters of cold shock gas and the first adiabatic layer cold air temperature controller accounts for about 5 %).
、由塔外热交换器加热的循环气，进入塔内下部换热器管内，与出塔气体换热以后，进入上部换热器管内，与在上绝热段反应后出混合分布器Ⅰ的气体换热后，从换热器与中心管之间的环隙向下进入中心管，经中心管进入催化剂床层表面与冷管束出来的气体汇合，在第一绝热层反应；反应气体在第一层中部冷气调温器中与从塔外引入的少量冷气混合后，继续反应；出第一绝热层的气体进入气体混合分布器Ⅰ，再进入塔内上部换热器管间，与进塔气体换热后，从上部换热器的外壳出去，进入第二层。 Another 50% of the circulating gas heated by the external heat exchanger enters the heat exchanger tubes in the lower part of the tower. After heat exchange with the gas exiting the tower, it enters the upper heat exchanger tubes and reacts with the upper adiabatic section. After heat exchange of the gas in the mixing distributor I, the ring gap between the heat exchanger and the central tube enters the central tube downward, enters the surface of the catalyst bed through the central tube, and merges with the gas from the cold tube bundle, and reacts in the first insulation layer. ; The reaction gas is mixed with a small amount of cold air introduced from outside the tower in the central cold air temperature regulator of the first layer, and the reaction continues; the gas exiting the first insulation layer enters the gas mixing distributor Ⅰ, and then enters the upper heat exchanger tube in the tower After exchanging heat with the gas entering the tower, it exits from the shell of the upper heat exchanger and enters the second floor. The gas passes from the center of the circle to the circumferential direction through the radial adiabatic section, and passes radially through the interstage cooler. ～ 15 ℃，进入第三层。 The gas coming out of the middle radial basket, that is, the second layer, is affected by the stent sleeve, and the ring gap between the radial basket and the inner cylinder is downward, and the inner and outer cylinder ring gap is indirectly cooled by 10 to 15 ° C, and enters the third layer. ℃出塔。 The gas flows from the circumferential direction radially through the lower insulation layer to the heat exchanger in the center of the radial basket, enters the heat exchanger shell from the heat exchanger shell to the lower heat exchanger tube, flows down from the upper part, and exchanges heat with the gas entering the tower. Drop to about 380 ℃ and exit the tower.
4.2 System flow
～ 4.0 MPa的蒸汽，出废锅的气体进入热交换器，温度降至70 ℃左右进入水冷器；出水冷器的气体温度降到35 ℃以下，进入冷交管间冷却分离氨后，温度降到16 ℃以下进入一级氨冷器，经一级氨冷冷却至－ 5 ℃，再经二级氨冷冷却到－ 10 ～－ 12 ℃，进入氨分离器分离氨后进冷交管内，冷却管间的热气体，本身温度提高到25 ℃左右出冷交，与新鲜气汇合后进循环机，开始新一轮循环。 The gas exiting the synthesis tower directly enters the waste pan, generating 3.0 to 4.0 MPa of steam. The gas exiting the waste pan enters the heat exchanger, and the temperature drops to about 70 ° C into the water cooler; the gas temperature of the outlet water cooler falls below 35 ° C. After entering into the cold-crossing tube for cooling and separating ammonia, the temperature drops below 16 ℃ and enters the first-stage ammonia cooler, which is cooled to － 5 ℃ by the first-stage ammonia cooling, and then cooled to -10 ～ -12 ℃ by the second-stage ammonia cooling and enters the ammonia. After the separator separates ammonia, it enters the cold-exchange pipes. The temperature of the hot gas between the cooling pipes rises to about 25 ℃ and exits the cold-exchange. After converging with the fresh gas, it enters the cycle machine and starts a new cycle.
型- φ 2200氨合成系统流程示意见图2 ，流程设计特点如下。 Ⅲ JD2000 -φ 2200 ammonia synthesis system flow diagram is shown in Figure 2 , the flow design features are as follows.
）充分利用反应热，反应气出塔温度高，出塔气温度约380 ℃，可产生3.0 ～ 4.0 MPa的中压蒸汽。 ( 1 ) Make full use of the heat of reaction. The temperature of the exit gas of the reaction gas is high, and the temperature of the exit gas is about 380 ℃, which can produce 3.0-4.0 MPa medium pressure steam.
）加大热交面积，将进塔未反应气预热至200 ～ 240 ℃，省去一个软水加热器，简化流程，减少系统阻力。 ( 2 ) Increase the heat transfer area, preheat the unreacted gas entering the tower to 200 ~ 240 ℃, eliminate a soft water heater, simplify the process and reduce system resistance.
）设两级氨冷，一级氨冷冷至－ 5 ℃，二级冷至－ 10 ～－ 12 ℃，在22 MPa压力下，氨含量降至2.2 ％以下，进塔氨含量低，且节约冷冻量。 ( 3 ) Set two-stage ammonia cooling, first-stage ammonia cooling to -5 ℃, and second-stage cooling to -10 to -12 ℃. Under 22 MPa pressure, the ammonia content drops below 2.2 %, and the ammonia content in the tower is low. And save refrigeration.
）进水冷器气体温度低，节约冷却水。 ( 4 ) The gas temperature of the inlet water cooler is low, which saves cooling water.
）补气补在冷交冷气出口、循环机进口，以降低补气压力，节约压缩机电耗，节省冷冻量。 ( 5 ) Make-up air is supplied at the outlet of the cold air-conditioning and the inlet of the cycle machine to reduce the pressure of the make-up air, save the power consumption of the compressor, and save the amount of refrigeration. The cycle machine is set in front of the tower, and the outlet pressure of the cycle machine is at the highest point of system pressure.
）放空点设在冷交冷气出口、补气接点以前，此处氨含量最低，惰气浓度高，可节约冷冻量，没有放掉新鲜气。 ( 6 ) The venting point is set before the cold- handed cold air outlet and the supplementary air contact. Here, the ammonia content is the lowest, and the inert gas concentration is high, which can save the amount of refrigeration and do not let off fresh gas.
）设补气氨冷，降低补气温度，有利于油水分离，减少带入合成系统的油水杂质。 ( 7 ) Aeration ammonia cooling is set to reduce the temperature of the supplemental gas, which is beneficial to the separation of oil and water and reduces the oil and water impurities brought into the synthesis system.
Figure 2 型 - φ 2200氨合成系统流程示意图 Ⅲ JD2000 - Schematic diagram of φ 2200 ammonia synthesis system
—合成塔； 2 —废锅； 3 —热交； 4 —水冷； 5 —冷交； 6 —二级氨冷； 1 —Synthesis tower; 2 —Waste pot; 3 —Hot cross; 4 —Water cooling; 5 —Cold cross; 6 —Secondary ammonia cooling;
—氨分； 8 —循环机； 9 —油分； 10 —补气氨冷； 11 —补气油分 7 —Ammonia; 8 —Circulation machine; 9 —Oil content; 10 —Supply gas ammonia cooling; 11 —Supply gas and oil content
5 Catalyst loading and temperature reduction
5.1 Catalyst loading
型- φ 2200氨合成内件催化剂的装填，按分段装填的原则，下绝热层装填少量φ 4.7 ～φ 6.7 mm的催化剂垫底，此占总装量的2.5 ％，其余装φ 2.5 ～φ 3.3 mm颗粒，占总装量的38.2 ％；第二层全部装φ 4.7 ～φ 6.7 mm的催化剂，占总装量的39.3 ％。 Ⅲ JD2000 - φ 2200 ammonia synthesis internal catalyst loading, according to the principle of section loading, the lower insulation layer is filled with a small amount of φ 4.7 ～ 6.7 mm catalyst bottom, which accounts for 2.5 % of the total loading, and the remaining φ 2.5 ～ φ 3.3 mm particles, accounting for 38.2 % of the total loading; the second layer contains all catalysts of φ 4.7 to φ 6.7 mm , accounting for 39.3 % of the total loading. ～φ 6.7 mm的催化剂盖面，占总装量的2.1 ％；冷气调温器用少量φ 4.7 ～φ 6.7 mm的催化剂盖面，占总装量的2.4 ％；其余装φ 3.3 ～φ 4.7 mm的催化剂，占总装量的15.5 ％。 In the first layer, the mixing distributor I is covered with a small amount of catalyst φ 4.7 to φ 6.7 mm , which accounts for 2.1 % of the total loading; the air-conditioning thermostat is covered with a small amount of catalyst φ 4.7 to φ 6.7 mm , which accounts for 2.4 % of the total loading. ; The rest are loaded with catalysts of φ 3.3 to φ 4.7 mm , accounting for 15.5 % of the total loading.
5.2 Catalyst temperature reduction
）“三高”，即高氢气浓度，高空速，高电炉功率。 ( 1 ) "Three highs", namely high hydrogen concentration, high space velocity, and high electric furnace power.
High hydrogen concentration, increasing the concentration of reactants, is conducive to the reduction reaction. ％～ 80 ％；还原后期不低于72 ％。 The hydrogen concentration is required to be 75 % to 80 %; the later stage of reduction is not less than 72 %.
At a high space velocity, the water vapor generated by the reduction reaction and the ammonia produced by the reaction are taken away as soon as possible to reduce the water vapor concentration.
％。 High electric furnace power is a prerequisite for high space velocity. During the reduction process, the electric furnace power is 100 % in most cases.
）“三低”，即低压力，低水汽浓度，低还原温度。 ( 2 ) "Three lows", that is, low pressure, low water vapor concentration, and low reduction temperature.
Although the pressure has no direct effect on the reduction reaction, but the pressure is low. When the space velocity is constant, the linear velocity of the air flow is fast, and the generated water vapor and ammonia can be easily carried away by the air flow to reduce the water vapor concentration. The pressure is low, and the axial temperature difference in the axial section is small. , Is the most effective operation method to reduce the temperature difference in the same plane. ～ 4.0 MPa为宜。 The initial reduction pressure is preferably 3.5 to 4.0 MPa .
The reduction reaction of the catalyst is a reversible reaction. A low water vapor concentration can reduce the reverse reaction and prevent the reduced catalyst from being oxidized. Low ammonia cooling temperature is a guarantee of low water vapor concentration. ～－ 15 ℃。 The ammonia cooling temperature in the main reduction stage must be controlled from -10 to -15 ℃.
的烧结速度，反应温度提高过快，活性铁晶粒长大的速度随之加快，引起活性下降。 The reduction reaction of the catalyst is an endothermic reaction. Increasing the reaction temperature can significantly speed up the reduction reaction, but at the same time, it also accelerates the sintering speed of the active α- Fe . If the reaction temperature is increased too quickly, the rate of active iron grain growth will follow. Speed up, causing a decrease in activity. ～ 450 ℃时，控制催化剂出水量达到80 ％左右为宜。 When the reduction temperature is 440 to 450 ℃, it is appropriate to control the amount of catalyst water to reach about 80 %.
There are many catalysts in large towers, and stratified reduction should be strictly implemented to open the temperature difference between the layers. When the upper layer is undergoing a reduction reaction, the temperature of the middle and lower layers is still very low, and most of the catalysts are still in the oxidation state, and will not be affected by the water vapor generated by the upper layer. This will ensure the reduction quality of the catalyst.
The same-plane temperature difference of the axial section should be strictly controlled. ℃左右，就要把温差缩小到5 ℃之内。 When the axial section is heated and reduced, if there is a large temperature difference in the same plane, the temperature difference in the same plane must be eliminated before the catalyst is reduced into the main phase (the temperature difference caused by the leak of the cover of the basket must be exposed to the cover), that is, the catalyst temperature is about 410 ℃ It is necessary to reduce the temperature difference to within 5 ℃. The large temperature difference between the planes will cause the reduction degree of the catalyst temperature difference to be different on both sides. The low reduction part has poor activity in normal production, and the same plane temperature difference will also occur, affecting production and affecting the safety of internal parts. Can not wait until the temperature difference is large before taking measures, the reduction of the small temperature difference after the main period of recovery, there is also the problem of different degrees of reduction. Therefore, the same-plane temperature difference control of the axial section is an important control link that cannot be ignored in the reduction process.
）底点催化剂温度470 ℃以上，维持8 ( 1 ) The bottom point catalyst temperature is above 470 ℃, maintaining 8 ；水汽浓度连续3 ～ 4 h在0.2 g/m 3以下。 h ; water vapor concentration is below 0.2 g / m 3 for 3 to 4 h .
）零米温度485 ～ 490 ℃维持8 h以上，同平面温差≤ 10 ℃。 ( 2 ) The temperature of zero meter is 485 ～ 490 ℃ for more than 8 hours , and the temperature difference between the same plane is ≤ 10 ℃.
）除零米和底点以外的各点达495 ℃以上的时间均在8 h以上。 ( 3 ) The time for each point other than zero meter and bottom point to reach above 495 ℃ is more than 8 h .
If the above three conditions are met, the catalyst will be reduced completely, and the electricity can be cut to reduce the temperature to light load production.
6 型- φ 2200氨合成的生产实践 Ⅲ JD2000 -Production Practice of φ 2200 Ammonia Synthesis
型- φ 2200氨合成已在山东鲁西化工集团工业园、湖北三宁化工有限责任公司、江苏恒盛化肥有限公司投入使用。 Ⅲ JD2000 - φ 2200 ammonia synthesis has been put into use in Shandong Luxi Chemical Group Industrial Park, Hubei Sanning Chemical Co., Ltd. and Jiangsu Hengsheng Fertilizer Co., Ltd.
Ⅲ JD2000型- φ 2200氨合成塔配套系统，完全按照“低零米温度、高热点温度、高出塔温度、高氨净值、高产量、大分流”的思想设计。 Ⅲ JD2000 - φ 2200 ammonia synthesis tower supporting system designed and manufactured for Luxi Chemical Group Industrial Park , completely in accordance with the "low zero meter temperature, high hot spot temperature, high tower temperature, high ammonia net value, high output, large diversion" Thought design.
φ 2200 氨合成系统，于2008年12月正式投入生产。 Hubei Sanning Chemical Co., Ltd. φ 2200 ammonia synthesis system was formally put into production in December 2008. ；设计生产能力220 kt/a 。 The device has a design pressure of 26.0 MPa and a design production capacity of 220 kt / a . ～ 880 t ，最高日产928 t ；循环气氢53.0 ％ ～ 57.0 ％； CH 4控制在18.0 ％ ～ 21.0 ％ ,总惰性气体达22 ％～ 24 ％ ；循环机开3 × 13.7 m 3 /min ；系统压力23.0 ～ 24.0 MPa ，塔阻力0.7 ～ 0.8 MPa ，系统阻力1.5 ～ 1 .7 MPa 。 At present, the actual daily output of liquid ammonia is 850 to 880 t , and the maximum daily output is 928 t . The circulating gas hydrogen is 53.0 % to 57.0 %. The CH 4 is controlled to 18.0 % to 21.0 % , and the total inert gas is 22 % to 24 % . The cycle machine is turned on 3 × 13.7. m 3 / min ; system pressure 23.0 ～ 24.0 MPa , tower resistance 0.7 ～ 0.8 MPa , system resistance 1.5 ～ 1.7 MPa . Catalyst bed temperature,
型- φ 2200 氨合成系统于2009年5月建成投产。 Jiangsu Hengsheng Fertilizer Co., Ltd. Ⅲ JD2000 - φ 2200 ammonia synthesis system was completed and put into production in May 2009. ；目前实际日产氨750 ～ 767 t （负荷未加满） , CH 4控制在19 ％ ～ 20 ％，惰气总量达23 ％ ～ 24 ％；循环机开4 × 12 m 3 /min ；系统压力21.2 MPa ，塔阻力0.65 MPa ，系统阻力1.33 MPa 。 The designed production capacity is 220 kt / a ; the current actual daily ammonia production is 750 to 767 t (the load is not full) , CH 4 is controlled at 19 % to 20 %, and the total amount of inert gas is 23 % to 24 %; the cycle machine is turned on 4 × 12 m 3 / min ; system pressure is 21.2 MPa , tower resistance is 0.65 MPa , and system resistance is 1.33 MPa . Catalyst bed temperature,
型- φ 2200氨合成的显著特点，一是产量高，合成塔的生产能力均能超过设计能力；二是压力低，在合成系统循环气中惰性气体成分控制比较高的情况下，反应压力仍然较低。 Ⅲ JD2000 -φ 2200 ammonia synthesis remarkable characteristics, first is the high output, the production capacity of the synthesis tower can exceed the design capacity; the second is the low pressure, in the synthesis system cycle gas inert gas composition control is relatively high, the reaction The pressure is still low. The output of ammonia synthesis system and the level of system pressure directly affect the energy consumption level of enterprises. 。 In the above companies, the energy consumption of ammonia synthesis has decreased significantly .
7 Problem discussion
型- φ 2200氨合成系统，自投用以来，产量高、压力低、能耗低的优势明显，但也有一些问题值得讨论。 Ⅲ JD2000 -φ 2200 ammonia synthesis system. Since its use, it has obvious advantages of high output, low pressure and low energy consumption, but there are also some issues worth discussing.
7.1 Tower drag problem
The tower resistance is mainly determined by the resistance of the catalyst bed and the flow resistance in the heat exchanger. ％，对降低阻力应十分有利。 The internal parts are two diameters and one axis, and the radial direction occupies 80 % of the whole tower catalytic bed, which should be very beneficial for reducing the resistance. This internal part has three heat exchangers, the cold tube bundle, and the tower heat exchange up and down. The cold tube bundle is an inner and outer ring in parallel up and down type, which is beneficial to reducing the resistance. The upper and lower heat transfer is a slender small row of tubes in series. Compared with a traditional bottom heat exchanger, it is more favorable for the reaction temperature. ％，主进气量占50 ％，若没有真正实现，生产中就会出现塔阻力较大的情况。 But when the gas volume is the same, the resistance is too large; therefore, to reduce its gas flow, the volume of air entering the cold pipe bundle during design is 50 %, and the main air intake volume is 50 %. Situation of greater resistance.
％）外，塔内流程准备进一步改进。 In addition to insisting on large diversions ( 50 %), the process in the tower is ready for further improvement. On the other hand, too much operation beyond the design capability is also the reason for the increase in resistance, and the degree of operation beyond the design should be appropriately controlled.
7.2 Out of tower temperature problem
℃，有一个氨厂实际达到了370 ℃，但人们认为高了，害怕出问题。 The exit temperature is designed to be 380 ° C. An ammonia plant actually reached 370 ° C, but people thought it was too high and was afraid of problems. 材质的锻件，在合成系统31.4 MPa压力下，可允许在400 ℃下使用。 In fact, forgings made of 1Cr5Mo can be used at 400 ℃ under the pressure of 31.4 MPa in the synthesis system. So it should be used with confidence. ～ 420 ℃，以提高废锅蒸汽产量；此时，塔下部四通及废锅管道得采用特殊材料。 Now some users have proposed that the temperature of the tower should be 415 ～ 420 ℃ in order to increase the steam output of the waste pot; at this time, special materials must be used for the lower part of the tower and the waste pot pipe.
7.3 Hot spot temperature issues
～ 515 ℃。 The hot spot temperature is relatively high, reaching 490 to 515 ℃. 一段的温升大，则氨净值高，整个合成塔生产能力大。 The hot spot temperature is high , and the temperature rise of the first stage is large, the net ammonia value is high, and the overall synthesis tower production capacity is large. ～ 480 ℃，热点温度高至515 ℃，人们不习惯，也难以接受，认为催化剂容易受损老化。 Because the hot spot temperature of traditional ammonia synthesis in China is 470 ~ 480 ℃, and the hot spot temperature is as high as 515 ℃, people are not used to it, and it is difficult to accept it. It is considered that the catalyst is easily damaged and aged. ℃。 However, the foreign industry, such as the "top" two-stage tower, the hot spot temperature design is 515 ℃.
Ⅲ JD型- φ 1600 氨塔，装填XA201宽温型催化剂，设计热点温度500 ℃；投产后 热点500 ℃运行两年， 510 ℃一年半； 2009年1月起，热点温度达 520 ℃；在四年多时间里，热点位置一直没变。 Jiangsu Huachang Chemical Co., Ltd. Ⅲ JD - φ 1600 ammonia tower, filled with XA201 wide temperature catalyst, designed hot spot temperature 500 ℃; hot spot operation at 500 ℃ for two years after operation, 510 ℃ for one and a half years; from January 2009, The hot spot temperature reached 520 ℃; the location of the hot spot has not changed for more than four years. The activity of the catalyst is in line with our expected effect. ，总惰气控制在20 ％～ 21 ％，系统压力25.5 ～ 26.0 MPa 。 At present, the daily ammonia production is 550 t , the total inert gas is controlled at 20 % to 21 %, and the system pressure is 25.5 to 26.0 MPa . It is estimated that the catalyst can also operate effectively for one to two years.
8 Concluding remarks
型- φ 2200氨合成塔是三层四段，两径一轴间接换热型反应器，是在深入研究氨合成反应原理，以及传热传质学、流体力学在特殊情况下的应用经验设计出来的，设计中的一些新思维通过了实践的验证，取得了很好的效果。 Ⅲ JD2000 -φ 2200 ammonia synthesis tower is a three-layer, four- segment , two-diameter and one-axis indirect heat exchange reactor. It is in-depth study of the principle of ammonia synthesis reaction, and the application of heat and mass transfer and fluid mechanics in special cases Designed by experience, some new ideas in the design have passed the verification of practice and achieved good results. 左右；系统CH 4 ＋ Ar高达20 ％以上，系统压力只有24.0 ～ 25.0 MPa ，操作平稳，运行安全，能耗下降明显，热回收率高，冷却水消耗低。 The outstanding advantage is that the single tower has a large capacity, and the daily ammonia production is about 900 tons ; the system CH 4 + Ar is over 20 %, the system pressure is only 24.0 to 25.0 MPa , the operation is stable, the operation is safe, the energy consumption is significantly reduced, the heat recovery rate is high, and the cooling water Low consumption. The ammonia synthesis technology has been greatly improved and has been well received by users.
型塔，如φ At present, Anchun company is designing low pressure, low resistance III JD3000 tower, such as φ