Courtyard House: Starting with handing over the keys, the state helps me abuse birds.

On the afternoon of the second day after Yi Zhonghai and others received meticulous treatment at the hospital, Xie Weihong was practicing her cultivation indoors.

"Wei Hong, are you there?" Duan Chengyi's voice was unusually urgent.

Upon opening the door, Xie Weihong saw Duan Chengyi standing outside. His dark blue Zhongshan suit was soaked with rain, and his expression was solemn and anxious.

"Uncle Duan, what happened?"

Duan Chengyi slipped into the room, closed the door behind him, and lowered his voice: "There's a problem with the fertilizer pilot test. It's stuck in the ammonia synthesis section. The conversion rate can reach 68% in the small-scale test, but after scaling up to the pilot scale, it can only reach 52%, which is a huge difference."

He pulled a crumpled document from his pocket, covered in red pen markings: "Engineer Chen and his team worked for five days and five nights, trying every possible solution, but the highest conversion rate was only 55%. Director Lu came to the base this morning and got angry, saying that this is a matter of life and death for hundreds of millions of people, and not a moment can be wasted."

Xie Weihong took the document and quickly scanned it. The paper contained dozens of sets of experimental data, attempts at adjusting various parameters, and dense analytical annotations written beside it. Judging from the illegible handwriting and coffee stains on the margins, the person who wrote this was utterly exhausted.

"What's the situation now?"

"Engineer Chen is still at the base, saying he won't leave the reactor until the problem is solved." Duan Chengyi smiled wryly. "He's fifty-six this year, has high blood pressure, and almost fainted at the control panel yesterday."

Xie Weihong remained silent for a moment.

"I'll go take a look."

"The car is waiting outside," Duan Chengyi said immediately. "Director Lu instructed that if you can solve the problem, the country will not forget this contribution."

The industrial zone in the west of the city looked particularly desolate in the autumn rain.

The car drove past rows of old factory buildings and finally stopped at a converted fertilizer pilot plant. Unlike the dilapidated surrounding factories, this place was brightly lit, and through the rain, one could see many people bustling about inside.

"This used to be the state-owned Hongxing Fertilizer Plant, which ceased production three years ago due to outdated technology," Duan Chengyi explained as he led the way. "In order to industrialize your technology as soon as possible, Director Lu made a special approval to transform this place into a pilot plant. The Ministry selected twelve top experts from across the country, with Engineer Chen as the chief person in charge."

The two walked through the covered walkway toward the control building in the center of the factory. Before they even entered, they could hear hoarse, heated discussions coming from inside.

"Mr. Wang, are you sure the recirculating gas compressor is working properly? I checked the operation logs three times. Yesterday afternoon between 3 and 4 pm, the outlet pressure fluctuated by 0.15 MPa!"

"The fluctuations are within the acceptable range! Engineer Li, you can't blame all the problems on the equipment! Our process team needs to double-check the calculations. Xiao Zhang, recalculate the material balance sheet using different methods!"

"Mr. Chen, please have something to eat. It's already 3 PM, and you haven't had breakfast yet..."

"Eat what! If the conversion rate isn't good, how can I afford to eat?!"

Pushing open the door, Xie Weihong was slightly taken aback by the scene inside the control room.

Seven or eight people were crammed into a room of less than forty square meters. The walls were covered with blueprints and graphs, and thick calculation sheets and experimental notebooks were spread out on the table. The air was filled with the mixed smells of coffee, tobacco, and sweat.

The elderly man in the center, with gray hair and wearing black-rimmed glasses, is Engineer Chen, the chief person in charge of the fertilizer project.

His eyes were bloodshot, his face haggard, his left hand pressed against his temple, while his right hand held a red and blue pencil, marking something on a drawing. The lunchbox on the table was already cold, and the steamed bun inside had only been bitten once.

A young man in his early thirties, Qi Mingyuan, was yelling into the phone, "Yes! I need the raw data from the catalyst factory's lab! Not the test reports, but the original records! I need the impurity content curves for every batch! What? It takes time? Do you know how many people across the country are waiting to eat?!"

He hung up the phone, slammed his fist on the table, turned around and saw Duan Chengyi. Just as he was about to speak, his gaze fell on Xie Weihong, and he paused for a moment.

"Chief Duan, who is this...?"

"Let me introduce you," Duan Chengyi said, stepping aside. "Comrade Xie Weihong is a senior technical advisor specially appointed by the ministry to address your issues."

There was a moment of silence in the control room.

Everyone looked at Xie Weihong with scrutiny, doubt, expectation, and undisguised suspicion. She was too young, too young for a "senior advisor".

Qi Mingyuan adjusted his glasses, his tone polite but distant: "Hello, Consultant Xie. May I ask which organization you worked for before? Do you have any research experience in ammonia synthesis technology?"

The question was direct, but it was also the question everyone present wanted to ask. Some of these people had returned from studying in the Soviet Union, while others were veteran engineers who had worked in fertilizer plants for twenty years. Each of them had been immersed in this field for more than a decade or even several decades. Now, a young man in his early twenties had suddenly appeared, claiming to be a "senior consultant," which inevitably aroused suspicion.

Xie Weihong did not answer directly, but walked to the control panel and looked at the real-time data of the reactor displayed on the screen.

"Ammonia synthesis section, conversion rate 52%, reaction pressure 22 MPa, temperature 485 degrees Celsius, space velocity 12000, nitrogen-to-hydrogen ratio 3.02:1..." He read the data steadily. "What are the data for the small-scale test?"

Engineer Chen looked up, a hint of surprise flashing in his tired eyes. This young man could accurately grasp the key parameters with just one glance, clearly he was no novice.

"The small-scale conversion rate was 68%, the pressure was 20 MPa, the temperature was 480 degrees, the space velocity was 10000, and the nitrogen-hydrogen ratio was 3:1," Engineer Chen replied. "We tried running it according to the small-scale parameters, and we also tried adjusting the pressure, temperature, space velocity, and even changing the catalyst loading method, but the highest conversion rate we achieved was only 55%."

Xie Weihong nodded, walked to the diagram of the reactor structure posted on the wall, and studied it carefully for three minutes.

No one spoke in the control room; only the low hum of the instruments and the patter of rain outside the window filled the air. Everyone stared at the young man who had suddenly appeared, wondering what he would say.

"What is the inner diameter of the small-scale reaction vessel?" Xie Weihong suddenly asked.

"200 millimeters," a middle-aged engineer replied.

"The current pilot-scale reactor?"

"1200 millimeters."

Xie Weihong turned around, picked up a red pen from the table, and drew a circle around the mixer position on the structural diagram.

"Here's the problem," he said calmly but clearly. "You only scaled up the geometric dimensions, not the fluid dynamics similarity."

"What do you mean?" Qi Mingyuan frowned.

Xie Weihong pointed to the structural diagram: "In the small-scale test reactor, with an inner diameter of 200 mm and a stirrer speed of 200 rpm, material mixing mainly relies on forced convection and turbulent diffusion. When scaled up to 1200 mm, the volume increases by 216 times. At the same stirring speed, the stirring Reynolds number drops from the turbulent region to the transitional flow region, and the material mixing efficiency decreases by at least 60%."

He paused, then looked at Engineer Chen: "There's no flow guide tube inside the reactor, is there?"

Engineer Chen was taken aback: "A flow guide tube? We don't have one for small-scale testing, so we don't have one for pilot-scale testing either..."

"Small-scale tests don't need it, but pilot-scale tests are a must," Xie Weihong interrupted him. "In large-scale reactors, without a flow guide, dead zones will form in the material, resulting in uneven reactant concentration distribution and local temperature differences of more than 20 degrees Celsius. Uneven catalyst bed temperature will naturally reduce activity."

The control room was completely silent.