Newbie here, may I ask about the structure, principle, and process of gas furnaces in nitrogen fertilizer plants?
Thread Content
I’m a newcomer to the field of coal chemistry, and I would like to ask those with more experience about the structural principles and operating processes of the gas generators used in nitrogen fertilizer plants. Our factory is a small to medium-sized enterprise; we have 10 gas generators with a diameter of 2600 mm, along with 5 sets of waste heat recovery systems. As a beginner in this field, there are many things I don’t know – such as the model of the generators, daily operation procedures, the relationship between the height of the carbon layer in the furnace and the amount of gas produced, how to adjust the hydrogen-to-nitrogen ratio, what the purpose of adding hydrogen during synthesis is, and what the function of the return pipes for steam entering the furnace, as well as the pressure regulators, is. The furnaces have six different operating modes: top blowing, bottom blowing, double top blowing, cleaning, blowing air, and recovery. These modes can be adjusted within a time range of 120–175 seconds, and the adjustment of the time for each mode has an impact on the performance of the furnace.
I. Job Responsibilities 1. The main task of this position is to produce semi-water gas (with a ratio of CO+H2 to N2 of around 3:1) used in the production of synthetic ammonia, using the intermittent fixed-bed atmospheric gasification process. That is, in a gas generator, using smokeless lump coal or coke as raw materials and maintaining a certain carbon layer, air and steam are alternately blown in at high temperatures to produce qualified semi-water gas. 2. Improve the utilization rate of fuel and steam to provide high-quality and sufficient semi-water gas for subsequent processes. II. Brief Description of the Process Flow
1. Gas flow: Gas generator → Upward (downward) pipe → Cyclone dust collector (downward dust collector) → Main gas pipeline → Separator → Waste heat boiler → Gas washing tower → Main gas washing tower → Gas holder
2. Steam flow:
(1) Jacketed water tank → Jacket of gas generator → Jacketed gas tank → Steam-water separator → Before urea addition or pressure reduction
(2) Combined water tank → Waste heat boiler → Combined gas tank → Vertical buffer tank → Horizontal buffer tank → Main steam pipeline → Upper (lower) blowing pipe → Gas generator
(3) Shifted superheated steam and thermoelectric saturated steam → Vertical buffer tank → Horizontal buffer tank → Main steam pipeline → Upper (lower) blowing pipe → Gas generator
3. Oil flow: Pump station → Main pipe for each furnace → Valve before the switching station → In front of the switching valve station on the second floor → Ports A and B at the bottom of the switching station → Oil pipes to each programmable valve → In front of the oil cylinders of each programmable valve
4. Water flow:
(1) Deionized water → Combined steam tank → Waste heat boiler →
(2) Urea condensate → Jacketed steam tank → Water jacket → Jacketed steam tank → Steam-water separator
(3) Secondary circulating water → Gas washing tower → Gas production circulating water
1. Gas flow: Gas generator → Upward (downward) pipe → Cyclone dust collector (downward dust collector) → Main gas pipeline → Separator → Waste heat boiler → Gas washing tower → Main gas washing tower → Gas holder
2. Steam flow:
(1) Jacketed water tank → Jacket of gas generator → Jacketed gas tank → Steam-water separator → Before urea addition or pressure reduction
(2) Combined water tank → Waste heat boiler → Combined gas tank → Vertical buffer tank → Horizontal buffer tank → Main steam pipeline → Upper (lower) blowing pipe → Gas generator
(3) Shifted superheated steam and thermoelectric saturated steam → Vertical buffer tank → Horizontal buffer tank → Main steam pipeline → Upper (lower) blowing pipe → Gas generator
3. Oil flow: Pump station → Main pipe for each furnace → Valve before the switching station → In front of the switching valve station on the second floor → Ports A and B at the bottom of the switching station → Oil pipes to each programmable valve → In front of the oil cylinders of each programmable valve
4. Water flow:
(1) Deionized water → Combined steam tank → Waste heat boiler →
(2) Urea condensate → Jacketed steam tank → Water jacket → Jacketed steam tank → Steam-water separator
(3) Secondary circulating water → Gas washing tower → Gas production circulating water
The equipment, processes, and techniques vary to some extent among different factories; it is best to find materials related to the specific position in one’s own factory for learning purposes. A fixed-bed gas generator can basically be divided into four parts: the feeding mechanism, the furnace body, the furnace bottom assembly, and the ash removal mechanism. (1) Blowing stage: blower, butterfly valve, blowing valve, gas generator, upward valve, cyclone dust collector, chimney valve for venting. (2) Recovery stage: blower, butterfly valve, air supply valve, gas generator, upward valve, main coal valve, safety water seal, comprehensive dust collector, combined waste boiler, gas scrubber, gas holder. (3) Upward blowing stage: buffer tank, total vapor, upward blowing, gas generator, upward valve, main coal valve, safety water seal, gas, dust collector, combined waste boiler, gas scrubber, gas holder. (4) Downward blowing stage: Buffer tank → Total steam → Downward blowing → Gas generator → Upward valve, main coal valve → Safety water seal → Gas dust collector → Combined waste boiler → Gas washing tower → Gas holder. (5) Secondary upward blowing stage: Buffer tank → Total steam → Upward blowing → Gas generator → Upward valve, main coal valve → Safety water seal → Gas dust collector → Combined waste boiler → Gas washing tower → Gas holder. (6) Purging stage: Blower → Butterfly valve → Blowing valve → Gas generator → Upward valve → Main coal valve → Safety water seal → Gas dust collector → Combined waste boiler → Gas washing tower → Gas holder
Thank you both. I hope everyone can offer more advice