Purification Technology Edition: One Question per Week [First Week of August 2017]

(1) Main reasons for the increased resistance in the conversion system: ① Increased resistance in the catalyst bed. a. Poor quality of the catalyst, low strength, and tendency to become powdered.       b. The operating temperature fluctuates greatly and frequently. The catalyst particles expand and contract repeatedly until they break apart.      C bed layer overheats for too long, causing the catalyst to sinter.       d. Water enters the catalyst bed, causing the catalyst to become wet, cracked, and caked.       e. The quality of the circulating hot water in the saturated hot water tower is poor, and the quality of the water used for spraying between the catalyst bed layers is also poor; inorganic salts in the water deposit within the catalyst bed layers.       ②Increased resistance in saturated hot water towers a. Semi-water gas contains many impurities such as coal tar, which can clog the tower trays or packing.       b. The total solid content of the circulating hot water in saturated hot water towers is high, which causes blockage of the tower plates and packing.      c. The liquid level in the saturated hot water tower is high.      ③‘High resistance of the heat exchanger a. Semi-water gas contains high levels of coal tar oil, which causes the tubes of the heat exchanger to become clogged with coal tar oil and iron oxide powder.       The catalyst surface forms a crust; gas backflow is used to blow the catalyst powder into the heat exchanger tubes.      ④Filler condensation, excessive liquid level in the cooling tower.      ⑤Water accumulates within the system, and the condensate is discharged when it has accumulated.

(1) Water in the feed gas entering the furnace causes catalyst cracking, leading to caking or agglomeration. (2) Fluctuations in the composition of the feed gas cause sharp rises and falls in temperature, leading to pulverization. (3) The mechanical impurities, dust, carbon black, and inorganic salts in the feed gas are present in high concentrations; they deposit on the surface of the catalyst, causing blockages. (4) High content of catalyst powder. (5) Rupture and pulverization occur due to the poor mechanical strength of the catalyst and frequent start-up and shutdown cycles.

⑴Water in the feed gas entering the furnace causes the catalyst to burst, leading to caking or agglomeration. ⑵Fluctuations in the composition of the feed gas cause sharp spikes and drops in temperature, leading to pulverization. ⑶The raw gas contains high levels of mechanical impurities, dust, carbon black, and inorganic salts, which deposit on the surface of the catalyst and cause clogging. ⑷The catalyst powder content is high. ⑸Due to the poor mechanical strength of the catalyst, frequent start-up and shutdown cycles cause cracking and pulverization.

. Moisture in the feed gas enters the furnace, causing the catalyst to explode and leading to caking or agglomeration. 2. Fluctuations in the composition of the feed gas cause sudden spikes and drops in temperature, leading to pulverization. 3. High levels of mechanical impurities, dust, carbon black, and inorganic salts in the feed gas settle on the surface of the catalyst, causing blockages. 4. High content of catalyst powder. 5. Due to the poor mechanical strength of the catalyst, cracking and pulverization occur as a result of frequent start-up and shutdown cycles.

Answer: (1) Water in the feed gas enters the furnace, causing the catalyst to burst, leading to caking or agglomeration. (2) Fluctuations in the composition of the feed gas cause sharp rises and falls in temperature, leading to pulverization. (3) The mechanical impurities, dust, carbon black, and inorganic salts in the feed gas are present in high amounts; they deposit on the surface of the catalyst, causing blockages. (4) High content of catalyst powder. (5) Rupture and pulverization occur due to the poor mechanical strength of the catalyst and frequent start-up and shutdown cycles.

: (1) Water in the feed gas entering the furnace causes catalyst explosion, leading to caking or agglomeration. ⑵Fluctuations in the composition of the feed gas cause sharp spikes and drops in temperature, leading to pulverization. ⑶The raw gas contains high levels of mechanical impurities, dust, carbon black, and inorganic salts, which deposit on the surface of the catalyst and cause clogging. ⑷The catalyst powder content is high. ⑸Due to the poor mechanical strength of the catalyst, frequent start-up and shutdown cycles cause cracking and pulverization.

a. The catalyst has poor quality, low strength, and is prone to pulverization. b. The operating temperature fluctuates greatly and frequently. The catalyst particles expand and contract repeatedly until they break apart. c. Excessive bed temperature for too long leads to catalyst sintering. d. Water enters the catalyst bed, causing the catalyst to become wet, break apart, and clump together. e. The quality of the circulating hot water in the saturated hot water tower is poor, and the quality of the water used for spraying between the catalyst bed layers is also poor; inorganic salts in the water deposit within the catalyst bed layers.

a. The catalyst has poor quality, low strength, and is prone to pulverization. b. The operating temperature fluctuates greatly and frequently. The catalyst particles expand and contract repeatedly until they break apart. c. Excessive bed temperature for too long leads to catalyst sintering. d. Water enters the catalyst bed, causing the catalyst to become wet, break apart, and clump together. e. The quality of the circulating hot water in the saturated hot water tower is poor, and the quality of the water used for spraying between the catalyst bed sections is also poor; inorganic salts in the water deposit within the catalyst bed.

1. Poor quality of the catalyst, low strength, and prone to pulverization； 2. The operating temperature fluctuates greatly and frequently. The catalyst particles expand and contract repeatedly until they break apart ； 3. Excessive bed temperature and prolonged exposure lead to catalyst sintering ； 4. Water enters the catalyst bed, causing the catalyst to become damp, break apart, and form clumps ； 5. The quality of the circulating hot water in the saturated hot water tower is poor, and the quality of the water used for spraying between the catalyst bed layers is also poor; inorganic salts in the water accumulate in the catalyst bed layers.

A. Catalyst pulverization； B. Catalyst sintering ； C. Solid particles in the gas adhere and form a crust on the surface of the catalyst.