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Brief description of the process flow: Introduction: Compiled based on the process flows of the delayed coking units, hydrogenation units, and hydrogen production units at companies such as Jinan Refinery and Haihua Group. And reference was also made to the materials provided by Luoyang Design Institute, Beijing Design Institute, and Huaxi Institute. I. 1 million tons/year delayed coking unit: The feedstock for this unit is vacuum residue, at a temperature of 150°C; it is sent directly from the atmospheric and vacuum distillation unit to the coking unit where it exchanges heat with diesel. After this heat exchange, the temperature rises to 170°C, after which the material enters the feedstock buffer tank (D-101). The vacuum residue in the feed oil buffer tank is pumped out by the feed oil pump; after exchanging heat twice with hot wax oil, it is heated in the convection section (II) of the heater. Thereafter, it enters the upper and lower sections of the five layers of herringbone baffles in the lower part of the coking distillation column (C-102), where it comes into contact with the oil and gas coming from the tops of the coke columns (C-101/1, 2) to facilitate heat and mass transfer. The fractions in the crude oil above the wax oil fraction, together with the fractions condensed from the overhead gas of the coke tower (referred to as recycled oil), flow to the bottom of the tower. At a temperature of 384°C, they are pumped into the radiant section of the heating furnace using a radiant feed pump; there they are rapidly heated to 500°C, after which they are sent to the bottom of the coke tower via a four-way valve. In the circulating oil and feed oil, the fractions above wax oil undergo a series of complex reactions such as cracking and condensation within the coke tower due to high temperatures and long residence times. These reactions result in the formation of hydrocarbons (including rich gas, gasoline, diesel, and wax oil), which then flow from the coke tower to the distillation tower, while the coke accumulates within the coke tower. The mixture of oil gas and water vapor escaping from the top of the coke tower enters the distillation tower, where it exchanges heat with the feedstock coming from the convective section of the heater. This results in the condensation of circulating oil fractions; the remaining large amount of oil gas rises from the heat exchange section into the distillation sections above the wax oil collection tank, where heat and mass transfer occur, leading to the separation of rich gas, gasoline, diesel, and wax oil. The wax oil from the oil collection tank of the coking fractionation tower is heated to 90°C before being sent out of the plant and into the wax oil tank ； Additionally, two streams of 90°C cold paraffin oil are introduced for use as quench oil at the top of the coke tower and as sealing oil for the plant. Mid-stage reflux generates steam in the mid-stage reflux steam generator. The distillation column top reflux is drawn from the column and returned after cooling. The diesel enters the stripping tower from the fractionation tower; after being stripped with steam, it is drawn out from the lower part of the gasoline tower. After being cooled to 70°C through heat exchange, it is divided into two streams, one of which goes to the hydrogenation unit ； The other stream is cooled to 40°C and sent to the diesel absorption tower as an absorbent. The rich gas from the compressed rich gas separation tank enters the lower part of the diesel absorption tower; after absorption, the dry gas at the top of the tower exits the facility and enters the plant’s fuel gas network ； The oil absorbed at the bottom of the tower is pressurized by the pressure of the tower (0.4 MPa gauge) and fed back into the distillation tower as reflux. The vapor and oil at the top of the distillation tower are cooled by an overhead cooler and a post-cooler for such vapor and oil, before entering a separation tank at the tower top. The gasoline that is separated is pumped out by a gasoline pump and sent in two directions: one stream goes to the hydrogenation unit, while the other stream returns to the top of the tower as reflux (this is not commonly used). The rich gas at the top of the oil-gas separation tank is pressurized by a rich gas compressor; after being cooled in a compressed rich gas air cooler and a compressed rich gas aftercooler, it enters the compressed rich gas liquid separation tank, where the condensate oil is sent to the hydrogenation unit ； The rich gas enters the lower part of the diesel absorption tower. Practical operation in some plants has shown that the dry gas after diesel absorption contains a significant amount of residual liquid, accounting for about 20% of the dry gas. In our company’s design, the rich gas coming from the top of the oil-gas separation tank can be pressurized using a rich gas compressor and then fed into the absorption and stabilization system of the aromatization unit or that of the catalytic unit, thereby preventing the dry gas from containing residual liquid. ). Furthermore, to prevent coking at the bottom of the distillation column, a bottom circulation pump is installed there. Coking cutting is carried out using a dual-drill rig with a derrick; the water used for coking cutting is pumped from a high-level water tank by a high-pressure water pump and delivered to the surface of the coke tower to carry out hydraulic coking removal. Coke and water flow together into the coke storage tank; after separation, the water used for cutting coke is sent to a sedimentation tank for reuse. When steam is introduced into the coke tower, the oil and gas first enter the oil and gas flash tank; the sludge at the bottom of the tank is pumped out of the system using a sludge pump ； The oil and gas at the top of the tank enter the water-cooled cooler; after cooling, they go into the steam-blown oil-water separation tank. The dirty oil at the bottom of the tank is pumped out using a dirty oil pump, while the sulfur-containing oily wastewater is pumped to the external wastewater treatment facility via a wastewater pump. Non-condensable gases enter the vent oil and gas dehydration tank, and then proceed to the gas system where they are burned in a flare. II. 600,000 tons/year hydrogenation unit 1. Reaction section: Coker gasoline and coker diesel are fed directly from the delayed coking unit; to ensure a steady hydrogenation reaction, their feeding ratios must be strictly controlled. After entering the unit, the two types of feedstocks are mixed in the feedstock mixing tank (D-201), and then pass through the feed oil pumps (P-201/1, 2), filters (SR-201/1, 2), and feed oil dehydration tank (D-202) before reaching the feed oil buffer tank (D-203). The purpose of filtering and dehydrating the feed oil is to remove solid particles that can clog the upper bed of the reactor, as well as moisture that can affect the strength of the catalyst. D-201 and D-203 are protected by a nitrogen gas seal. The feedstock in D-203 is pressurized to 9.6 MPa (A) by the reaction feed pumps (P-202/1, 2). After flow control, it is mixed with hydrogen from the new hydrogen compressors (K-201/1, 2) and the recycled hydrogen compressors (K-202/1, 2). It first exchanges heat with the mixed hydrogen feedstock (I)/reaction product heat exchanger (E-204/1, 2), and then exchanges heat with the reaction products via the mixed hydrogen feedstock (II)/reaction product heat exchanger (E-201) to reach a temperature of 199°C, after which it enters the reaction heating furnace (F-201). There, it is heated to 303°C before entering the hydrogenation reactor (R-201), which is equipped with two catalyst beds, with emergency cooling hydrogen injection facilities provided between these two beds. The reaction products coming from reactor (R-201) undergo heat exchange through the hydrogen-blended feed (II)/reaction products heat exchanger (E-201), the stripping tower bottom oil/reaction products heat exchanger (E-202), the light fraction oil/reaction products heat exchanger (E-203), and the hydrogen-blended feed (I)/reaction products heat exchangers (E-204/1, 2). Subsequently, they are cooled to 40°C via the reaction products air cooler (EC-201/1, 2) and the reaction products after-cooler (E-207/1, 2), before entering the high-pressure separator (D-204). To prevent the ammonium salts in the reaction products from crystallizing in low-temperature areas, deoxygenated water is injected into the pipelines upstream of (EC-201/1,2) or (E-204/1,2) via deoxygenated water pumps (P-207/1,2). The cooled reactant undergoes three-phase separation of oil, gas, and water in D-204. The high-pressure hydrogen (cyclic hydrogen), after being separated in the liquid separation tanks (D-208) at the inlets of K-202/1, 2, enters the cyclic hydrogen compressors (K-202/1, 2) where its pressure is increased to 8.8 MPa (G). It then splits into two streams: one stream serves as quench hydrogen and enters R-201, while the other stream mixes with the fresh hydrogen from the fresh hydrogen compressors (K-201/1, 2). This mixed hydrogen is then combined with the feed oil to serve as the reaction feed. Sulfur- and ammonia-containing wastewater is discharged from the bottom of D-204 and sent outside the plant for centralized treatment. Under level control, the D-204 oil phase enters the low-pressure separator (D-205) via a pressure-reducing control valve; the vapor from D-205 is discharged to the fuel gas network. The low-boiling fraction oil is exchanged heat with refined heavy naphtha and reaction products via the low-boiling fraction oil/fractionator bottom oil heat exchangers (E-206/1, 2) and E-203 until it reaches 200°C, after which it is sent to the stripping tower (C-201) in the fractionation section. The stripper bottom oil is heated to 245°C by heat exchange with refined heavy naphtha and reaction products through the stripper bottom oil/distillation tower bottom oil heat exchanger (E-205) and E-202, respectively, before being sent to the distillation section of the distillation tower (C-202). The newly produced hydrogen enters via the liquid separation tank (D-207) at the inlet of the new hydrogen compressor; after liquid separation, it proceeds to K-201/1, 2 and is pressurized in three stages to 8.8 MPa(G), after which it is mixed with the recycled hydrogen coming from the outlets of K-202/1, 2. 2. Fractionation section: The light oil coming from the reaction section enters C-201 after heat exchange. The bottom of the tower is stripped with 0.8 MPa superheated steam. The vapor and oil at the top of the tower are condensed and cooled to 40°C by the overhead cooler of the stripping tower (EC-202/1, 2) and the rear cooler of the stripping tower (E-208), after which they enter the reflux tank at the top of the stripping tower (D-210) for three-phase separation of gas, oil, and water. The vaporized gas enters the fuel pipeline network as fuel. Sulfur-containing wastewater discharge device. The oil phase is pressurized by the reboiler top reflux pumps (P-203/1, 2) and then returned entirely to the reboiler (C-201) as tower top reflux. The bottom oil, under its own pressure, flows through E-205 to exchange heat with refined heavy naphtha, and then goes to the reactor section’s E-202 heat exchanger. The low-grade oil from the reaction section enters C-202 after heat exchange. The bottom of the tower is heated by a reboiler. The vapor and oil at the top of the tower are cooled to 40°C by the overhead cooler of the distillation tower (EC-203/1, 2) and the rear cooler of the distillation tower (E-209), before entering the reflux tank at the top of the distillation tower (D-211) for three-phase separation of gas, oil, and water. The vaporized gas is sent to the flare through a vent tank. Sulfur-containing wastewater discharge device. After being pressurized by the reboiler top reflux pumps (P-204/1, 2), part of the oil phase is used as tower top reflux, while another part is sent out of the plant as refined light naphtha. A small portion of the refined heavy naphtha at the bottom of the tower is pressurized by the distillation column bottom product pumps (P-206/1, 2), and then passes through E-205 and E-206/1, 2 to exchange heat with the stripping column bottom oil and the light fraction oil until the temperature reaches around 100°C. After that, it enters the refined heavy naphtha after-cooler (E-210) where it is cooled to 60°C before leaving the plant. Most of the refined heavy naphtha at the bottom of the tower is pressurized by the bottom of the distillation tower circulation pumps (P-205/1, 2), heated to around 290°C in the bottom reboiler of the distillation tower (F-202), and then returned to the lower part of the distillation tower to supply the energy required for distillation. To suppress the corrosion of the top-of-tower pipes and heat exchangers caused by hydrogen sulfide, a corrosion inhibitor is injected into the top-of-tower pipes. After being pumped out from the corrosion inhibitor tank (D-212) via the corrosion inhibitor pumps (P-209/1, 2), the corrosion inhibitor is divided into two streams; one stream is fed into the overhead pipeline of tower C-201 ； The other stream is injected into the C-202 tower top pipeline. 3. Catalyst presulfurization section: To ensure good activity of the catalyst, both fresh and regenerated catalysts must be presulfurized before use. This design employs wet vulcanization, using straight-run kerosene as the vulcanizing oil and carbon disulfide as the vulcanizing agent. During the pre-sulfurization of the catalyst, the hydrogen in the system is fully circulated via the recycle hydrogen compressors (K-202/1, 2) in accordance with the normal operating procedure. Carbon disulfide is pressurized from the carbon disulfide tank using a sulfiding agent pump (P-208) and then sent to the inlet of the reaction feed pump. There, it mixes with hydrogen; after that, it exchanges heat with the reaction products and the hydrogen-blended feed oil in the heat exchangers (E-204/1, 2, E-201). It is then heated by the reaction feed heater (F-201), and finally passes through the catalyst bed to pre-sulfidize the catalyst. The sulfurized oil and recycled hydrogen coming out of the bottom of the reactor undergo heat exchange in E-201, E-202, E-203, and E-204/1, 2, and are then cooled in EC-201/1, 2, and E-207/1, 2 before proceeding to the high-pressure separator (D-204) for the separation of gas, oil, and water. The gas emerges from the top, enters K-202/1 and 2 via D-208 to enable the circulation of hydrogen; the sulfurized oil comes out from the lower part of the high-pressure tank (D-204), is depressurized through a control valve, and then enters the low-pressure tank (D-205) where it is separated by vaporization, with the liquid phase returning to the inlet of the crude oil buffer tank (D-203) to facilitate cyclic fluidization. The low-pressure gas resulting from flashing is sent to the fuel gas system, while the water generated during the catalyst pre-sulfidation process is discharged intermittently from the bottom of the high-pressure tank (D-204). After the catalyst pre-vulcanization is completed, the vulcanized oil, which serves as an improved feedstock, leaves the plant via the output line. III. Hydrogen production unit with a capacity of 10,000 cubic meters per hour 1. Feed system: Dry gas coming from outside the unit enters the raw gas buffer tank; after being compressed by the raw gas compressor, it proceeds to the raw gas desulfurization section. 2. Desulfurization section: The raw gas entering the desulfurization section is preheated to 380°C in a raw material preheater, then sent to a hydrogenation reactor where it reacts to convert organic sulfur into hydrogen sulfide. This hydrogen sulfide subsequently enters a zinc oxide desulfurization reactor, where it reacts with zinc oxide to form solid zinc sulfide, which is then absorbed. The sulfur content in the gas after hydrogen sulfide removal is less than 0.2 PPm, and it then enters the conversion section. The specific reactions are as follows: Thiol: RSH + H2 → RH + H2S; Thioether: R1SR2 + 2H2 → R1H + R2H + H2S; Dithioether: R1SSR2 + 3H2 → R1H + R2H + 2H2S; Thiophene: C4H4S + 4H2 → C4H10 + H2S; Carbon disulfide oxide: COS + H2 → CO + H2S; Carbon disulfide: CS2 + 4H2 → CH4 + 2H2S; ZnO (solid) + H2S → ZnS (solid) + H2O. ΔH°298 = -76.62 kJ/mol. 3. Conversion stage: The purified feed gas is mixed with steam in a water-to-carbon ratio of 3.5, then preheated to 500°C in the convective section of the conversion furnace before entering its radiant section. Under the action of a catalyst, complex water vapor conversion reactions take place, resulting in an equilibrium mixture of hydrogen, methane, carbon monoxide, carbon dioxide, and water. The main reactions are: CnHm + nH2O = nCO + (n + m/2)H2 ① CO + 3H2 = CH4 + H2O, ΔH298 = -206 kJ/mol ② CO + H2O = CO2 + H2, ΔH298 = -41 kJ/mol ③ For gaseous hydrocarbons dominated by methane, the steam reforming process is relatively simple, with the aforementioned reactions taking place; the composition of the final product gas is determined by the equilibrium of reactions ② and ③. As light naphtha has a complex composition comprising alkanes, cycloalkanes, aromatics, etc., in addition to the reactions mentioned above, reactions such as thermal cracking, catalytic cracking, dehydrogenation, hydrogenation, carbon deposition, oxidation, reforming, and methanation of higher hydrocarbons also occur in different catalytic beds. The composition of the final product gas is still determined by the equilibrium of reactions ② and ③. The hydrocarbon steam conversion reaction is a highly endothermic reaction that results in an increase in volume; low pressure, high temperature, and a high water-to-carbon ratio are favorable for the progress of this reaction. The heat required for the reaction process is provided by the gaseous fuel burners at the top of the conversion furnace. The conversion gas, which exits the furnace at a temperature of 820°C, has its temperature reduced to 360°C after heat exchange in the conversion gas steam generator, before entering the medium-temperature conversion section. 4. Shift section: The conversion gas at approximately 360°C, originating from the conversion section, enters the medium-temperature shift reactor, where a shift reaction takes place under the action of a catalyst: CO + H2O = CO2 + H2