采用气相吸附工艺,原料气不能含有任何液体或固体.
本说明中涉及到的压力均为表压,组成浓度均为摩尔百分比数,;流量除专门标注外均为标准状态下的流量.
二 工艺说明
本装置采用四塔二均工艺流程,它的关键部分由四个吸附塔(简称A,B,C,D)和气动阀,调节阀,截止阀组成.另外在原料气输入管路上配一个原料气缓冲罐(E) 在产品气输出管路上配一个氢缓冲罐(F),使产品气稳定的输出. 在解吸气输出管路上配一个解吸气缓冲罐(G),然后输入燃烧系统燃烧.
(一) 工作原理
变压吸附（PSA）技术是以特定的吸附剂(多孔固体物质)内部表面对气体分子的物理吸附为基础，利用吸附剂在相同压力下易吸附高沸点组分、不易吸附低沸点组分和高压下吸附量增加、低压下吸附量减少的特性，将原料气在一定压力下通过吸附床，相对于氢的高沸点杂质组分被选择性吸附，低沸点的氢气不易被吸附而穿过吸附床，达到氢和杂质组分的分离。
氢气提纯采用四塔二均工艺。
吸附完成后，吸附剂在减压下解吸被吸附的杂质组分，使吸附剂获得再生，以能再次进行吸附分离杂质。
本装置的四个吸附塔是交替进行吸附、解吸和吸附准备过程来达到连续生产氢气的。在吸附-解吸的过程中，吸附完毕的塔内仍保留着一部分纯氢，利用这部分纯氢给刚解吸完毕的另外两个塔分别均压（有两次，称为二均）和冲洗，这样做不仅利用了吸附塔内残存的氢气。
合格的氨分解气经过一套由4台吸附塔并联交替操作的变压吸附系统，一次性吸附分离所有杂质，得到纯度和杂质含量均合格的产品氢气。
吸附塔压力降至低压
首先是顺着吸附的方向进行降压(以下简称为顺向放压)，接着是逆吸附的方向进行降压（以下简称为逆向放压）。顺向放压时，有一部分吸附剂仍处于吸附状态。逆向放压时，被吸附的部分杂质从吸附剂中解吸出来，并被排除出吸附塔。
用产品气在低压下冲洗吸附剂， 以清除尚残留于吸附剂中是杂质。
吸附塔升压到吸附压力，以准备再次分离原料气。
本装置采用四塔二次均压吸附过程，即每个吸附塔在一次循环中均需要经历吸附（A）、一次均压（IED），顺向放压（PP）、二次均压（2ED）、逆向放压（D）、冲洗（P）、一次升压（2ER）、二次升压（IER）、以及最终升压（FR）等九个步骤，四个吸附塔在执行程序的安排上相互错开，构成一个闭路循环，以保证原料连续输入和产品不断输出。
整个过程主要由五只多通道滑管阀和二只梭阀来实现。
程控阀的功能说明如下：（见PSA-H2氢气提纯工艺流程图）
KV1ab——A、B塔进料及逆向放压，冲洗排放
KV1cd——C、D塔进料及逆向放压，冲洗排放
KV2ab——A、B塔产品输出，以C、D塔终充，对A、B塔均压，冲洗
KV2cd——C、D塔产品输出，以A、B塔终充，对C、D塔均压，冲洗
KV3——二次均压及逆向放压，冲洗排放切换阀
G2——产品输出选择阀
G3——二次均压选择阀
A、B、C、D——吸附塔
F——氢缓冲罐
V101——最终升压调节阀
V102——顺向放压调节阀
E——原料气二级分离器
G——解吸气缓冲罐
现以A塔为例对工作过程进行说明
1、 吸附（A）
原料气通过多通道滑管阀Kvab进入A塔，A塔在工作压力正吸附流入原料气中的杂质组份，未被吸附的产品组份H2通过多通道滑管阀KV2ab和梭阀G2流出，其中大部分作为产品从本系统中输出。剩余部分通过调节针阀V101和多通道滑管阀KV2cd向D塔进行最终级升压，吸附过程直至输出产品杂质浓度超过规定值时结束。
2、 一次降压平衡（IED），简称：一次均压
操纵多通道滑管阀KV1ab，切断进A塔原料气，同时操纵多通道滑管阀KV2ab，使A塔与刚结束一次升压步骤的B塔以出口端相连，实行一次压力平衡，一次均压后A、B塔压力基本相等。回收了A塔的死空间的H2。
3、 顺向放压（PP），简称；顺放。
A塔完成一次降压平衡（IED）步骤后，又操纵多通道滑管阀KV2ab，使B塔最终升压；A塔内剩余气体顺着出口方向通过多通道滑管阀KV2ab，再通过调节针阀V102限流，然后再通过多通道滑管阀KV2cd向刚完成逆向放压的C塔进行冲洗。当A塔压力降至规定值后，停止顺向放压，进行下一步骤。
4、 二次降压平衡（2ED），简称：二次均压。
操纵多通道滑管阀KV3，使A塔剩余的气体流过选择阀G3进入C塔底部，实现二次均压后A、C塔压力基本相等，又进一步的回收了A塔的死空间的H2。
5、 逆向放压（D），简称：逆放。
A塔二次均压（2ED）结束后，操纵多通道滑管阀KV1ab，使A塔内剩余的气体从塔的入口端排出放空，A塔进行脱附。
6、 冲洗（P）
A塔逆放后，尚残留在塔内的杂质是利用D塔的顺放气，通过多通道滑管阀KV2cd，再通过调节针阀V102限流，然后再通过多通道滑管阀KV2ab向刚完成逆向放压的A塔床层进行冲洗，塔内杂质进一小脱附，冲洗脱附气通道滑管阀KV1ab，排出放空。
7、 一次升压平衡（2ED），简称：一次升压。
A塔冲洗步骤结束后，操纵多通道滑管阀KV3，使A塔排放处关闭，利用D塔顺放后的剩余压力对A塔进行顺向压力平衡。A塔压力升高直至两塔压力基本相等，此时回收D塔空间的H2。
8、 二次升压平衡（IER），简称：二次升压。
在一次升压步骤结束后，操纵多通道阀KV1ab处于中封状态，同时操纵多通道滑管阀KV2ab处于中通状态利用B塔的一次均压气对A塔进行压力A塔压力进一小升高，直至两塔压力基本相等，此时回收了B塔死空间的H2。
9、 最终升压（ER），简称：终充
三、设备组成
1、 高效活性碳
2、 吸附剂（高效分子筛）
3、 活性氧化铝（吸水型）
4、 吸附塔（四台吸附塔）
5、 原料气罐、产品罐、解吸气罐（共3台）
6、 氢气连续分析仪（防爆型）
7、 流量仪表（金属转子流量计2台指示型）
8、 压力调节系统2套（包括压力变送器、调节器、调节阀等）
9、 遥控调节系统（包括手操遥控板、调节门共3套）
10、 集成式程控阀（共9台件，包括阻火器）
11、 程控系统（包括程控电脑、电气转换、控制箱、气动管线及管件）
12、 其他仪表
13、 柜式仪表盘
14、 手动阀门、仪表阀门
15、 安装材料
By gas adsorption process, a feed gas not contain any liquid or solid.
Pressure in this note relates both to gauge the composition concentration percentages are mole numbers; in addition to traffic flow are specially marked outside under standard conditions.
Two process description
The device uses four towers are two processes, it is a key part consists of four adsorption towers (called A, B, C, D) and pneumatic valves, control valves, shut-off valves. Also in the feed gas pipeline with a raw material input gas buffer tank (E) in the product pipeline gas output buffer with a hydrogen tank (F), so that a stable output product gas in the desorption gas export pipeline with a buffer solution suction tank (G), then enter the combustion system combustion.
(A) Works
Pressure Swing Adsorption (PSA) technology is based on a specific adsorbent (porous solid matter) on the interior surface of the physical adsorption of gas molecules based on the use of adsorbent at the same pressure and easy absorption of high boiling components, easy absorption and low boiling point components under high pressure adsorption amount increases, reducing the amount of absorption under low pressure characteristics through the adsorbent bed, relative to the high-boiling impurities are selectively adsorbed component of hydrogen, low boiling point is not easily adsorbed hydrogen pass through the adsorption feed gas under pressure bed, to separate hydrogen and impurity components.
Hydrogen purification process are two four-tower.
After the completion of adsorption, the adsorbent under reduced pressure to desorb the adsorbed impurity components so obtained adsorbent regeneration in the adsorptive separation of impurities can be performed again.
Four adsorption towers of the present apparatus is for absorption, adsorption and desorption of the preparation process to achieve continuous hydrogen production. Adsorption - desorption process, the adsorption tower completed still retains a portion of pure hydrogen, pure hydrogen to the use of this part of the desorption just completed two other towers were equalizing (twice, two were called) and rinsed not only does the use of the remaining hydrogen adsorption tower.
Qualified decomposition of ammonia gas through a pressure swing adsorption system made up of four parallel adsorber alternately operated, disposable adsorptive separation of all impurities, purity and impurity content of the qualified product hydrogen.
Adsorber pressure dropped to a low pressure
The first is along the direction of the adsorption step down (hereinafter referred to as forward pressure release), followed by adsorption step down inverse direction (hereinafter referred to as countercurrent depressurization). When the pressure put forward, there is still a part of the adsorbent in the adsorption mode. When countercurrent depressurization, some impurities are desorbed from the adsorbent adsorbed out and excluded from the adsorption tower.
Washing the adsorbent with the product gas at low pressure, yet to remove impurities remaining in the adsorbent.
Adsorber to adsorption pressure booster, separating the feed gas to prepare again.
The device uses four towers are secondary pressure swing adsorption process, that is, each adsorption tower in a loop to go through both adsorption (A), a pressure equalizing (IED), cocurrent depressurization (PP), secondary equalizing (2ED ), countercurrent depressurization (the D), rinse (the P), a booster (2ER), second boost (the IER), and the final boost (FR) et nine steps, four adsorption columns arranged in execution of the program on staggered to form a closed loop, in order to ensure a continuous input of raw materials and products continue to export.
The whole process consists of more than five-channel slide pipe valves and two shuttle valve to achieve.
Programmable valve function follows :( see PSA-H2 hydrogen purification process flow diagram)
KV1ab - A, B column feed and countercurrent depressurization, flushing emissions
KV1cd - C, D column feed and countercurrent depressurization, flushing emissions
KV2ab - A, B tower product output to C, D tower final charge of A, B tower equalizing, flushing
KV2cd - C, D column product output to A, B tower final charge on the C, D tower equalizing, flushing
KV3-- secondary equalizing and countercurrent depressurization, flushing discharge switching valve
G2-- product output selector valve
G3-- secondary equalizing valve choice
A, B, C, D-- adsorption tower
F-- hydrogen buffer tank
V101-- final boost regulator valve
V102-- forward pressure release valve
E-- two feed gas separator
G-- desorbed buffer tank
A tower is to be described as an example of the work process
1, absorption (A)
The feed gas through a multi-channel slide pipe into the valve Kvab A tower, A tower in the working pressures are flowing into the adsorption feed gas impurities parts group, product group is not part of H2 adsorption by multi-channel slide pipe valve and shuttle valve G2 KV2ab outflow, most of which as a product output from this system. By adjusting the remaining portion of the needle valve V101 and multi-channel slide pipe valve KV2cd D tower to boost the final stage, the adsorption process until the output product impurity concentration exceeds a predetermined value at the end.
2, a buck balance (IED), referred to as: first equalizing
Manipulate multi-channel slide pipe valve KV1ab, cut off the feed gas into the A column, and manipulate multi-channel slide pipe valve KV2ab, the A tower with a boost just after the step B tower is connected to the outlet end, the implementation of a pressure equalization, equalizing once after the A, B column pressure substantially equal. Recovered H2 A tower of dead space.
3, cocurrent depressurization (PP), short; smooth discharge.
A tower after completion of a step-down balance (IED) step, and manipulate multi-channel slide pipe valve KV2ab, so that tower B final boost; A tower along the residual gas outlet direction through a multi-channel slide pipe valve KV2ab, and then by adjusting the needle limiting valve V102 and then through a multi-channel slide pipe valve KV2cd just finished countercurrent depressurization to the C column flush. A column when the pressure dropped to a predetermined value, stop the forward pressure release, proceed to the next step.
4, the second step-down balance (2ED), referred to as: secondary equalizing.
Manipulate multi-channel slide pipe valve KV3, the A tower remaining gas flow through the selector valve G3 into the bottom of column C, realized after the second equalizing A, C column pressure substantially equal, further recovery of the A column dead space H2 .
5, countercurrent depressurization (D), referred to as: reverse discharge.
A second tower equalizing (2ED) after the end of the slide valve operated multichannel KV1ab, the A tower remaining gas is discharged from the inlet end of the column venting, A tower desorption.
6, rinse (P)
A reverse tower after discharge, still remaining in the column impurities using D column along deflated by a multi-channel slide pipe valve KV2cd, then the current limit by adjusting the needle valve V102, and then through a multi-channel slide pipe valve to just KV2ab a complete countercurrent depressurization of the bed to wash tower, the tower into a small impurity desorption, the desorption gas flushing channel slide valve KV1ab, exhaust vent.
7, a boost balance (2ED), referred to as: a boost.
A rinsing step after the end of the tower, operated a multi-channel slide pipe valve KV3, so A discharge tower is closed, along with the remaining pressure column D after the release of A tower along the equilibrium pressure. A tower pressure increases until the pressure is substantially equal to the two towers, then recovered H2 D column space.
8, the second boost balance (IER), referred to as: second boost.
After a step-up step is over, control of multi-channel valve KV1ab in the closed state, and manipulate multi-channel slide pipe valve KV2ab in use in state B tower once equalizing air pressure on the A column A column pressure into a small rise until two column pressure substantially equal, then recovered H2 B tower dead space.
9, the final boost (ER), referred to as: the final charge
Third, the device consisting of
1, efficient activated carbon
2, the adsorbent (molecular sieve efficient)
3, activated alumina (water based)
4, the adsorption towers (four adsorption towers)
5, raw material tank, product tank, desorption tank (3 sets)
6, continuous hydrogen analyzer (explosion proof)
7, flow meters (2 sets of metal rotameter indication type)
8, 2 sets of pressure regulation system (including pressure transmitters, regulators, control valves, etc.)
9, remote regulation system (including handheld remote control panel, a total of three sets of damper)
10, with integrated programmable valve (a total of nine members, including the flame arrester)
11, programmable control system (including program-controlled computer, electrical converters, control box, pneumatic lines and fittings)
12, other instruments
13, cabinet dashboard
14, manual valves, instrumentation valves
15, installation materials
