With the growing scale of the sulfur-containing natural gas and coal chemical industry, as well as economic growth and environmental protection factors, related gas desulfurization and sulfur recovery technologies have become more and more important. Sulfur recovery unit matching with oil refinery equipment has become an emerging industry in the new century.
Claus sulfur recovery unit techniques bring into industrialization 100 years ago, which were used to recycle sulfur contained in H2S gas. This technique is the standard technique for processing in sulfur recovery unit systems. With the increase in crude oil production in the Middle East, the sulphur recovery unit in the refinery needs to carry out high-load continuous production. So reliable operation of the sulfur recovery unit system is required, which is important to ensure upstream equipment safely running. A lot of sulfur recovery unit equipment has been built all over the world. Plus the pollution material will be more and more critically restricted. Environment protection law will be stricter for the main pollution material processing equipment. All the factors above request to improve the skills in equipment designing and selection of sulphur recovery units in the refinery.
Sulfur Recovery Unit Technological Process and Major Equipment
The sulfur recovery unit is responsible for converting the sulfide in the toxic sulfur-containing gas produced in the refinery process into elemental sulfur and removing harmful substances in the tail gas. We divide the technological process of the sulfur recovery unit into eight steps. The major equipment used includes a heat reactor furnace, waste heat boiler, sulfur condensers, catalyzing reactors, heat exchangers, and fluid delivery pipes
- Generation and collection. Sulfur steam is produced in the heat reactor where the acid gas containing hydrogen sulfide is mixing proportionally with air, which is collected from the desulfurization equipment and the acid stripping system.
- Cooling down. Process gas from the heat reactor is cooled down to 315℃, where the medium pressure steam is produced.
- 1st level condensing. Process gas from the waste heat boiler is cooled down further to 130℃ in the primary stage condenser, where the sulfur stream is condensed and separated flowing to the sulfur pool.
- 2nd level condensing. The process gas from the primary condenser is heated up to 260-290℃ by the waste heat of the gas and comes into the primary reactor where the sulfur stream is produced by the further reaction. Process gas in this step is cooled down to 130℃ in the second condenser, where the sulfur stream is cooled and separated flowing to the sulfur pool.
- Re-heat and 3rd level condensing. The process gas from the second condenser comes into the second reactor (where the sulfur stream produced by further reaction) after heated to 220-250℃ by the process gas from the primary reactor, and then the process gas comes into the third condenser cooled down to 130℃ and separated flowing to the sulfur pool. The recovery ratio can reach 95%.
- TGTU to increase the recovery rate. In order to further increase the sulfur conversion ratio, hydrogenation deoxidizes treatment must be added to the tail gas that comes from the Claus SRU unit. This is also called the tail gas treatment unit. Tail gas from the sulfur recovery unit is mixed with hydrogen after heated and send to the hydrogenation reactor, where the H2S is formed under the catalyzing reaction. So the carbon disulfide can be hydrolyzed. The reaction equation is shown below:
SO2 + 3H2 → H2S + 2H2O
SY + yH2 → yH2S
COS + H2O → H2S + CO2
CS2 + 2H2O → 2H2S + CO2 - Process gas from the hydrogenation reactor is cooled down by heat exchange with water and then is sent to the absorber. H2S contained in the process gas is absorbed by amine and then is sent to the acid gas pipeline.
- The gas from the absorber contains minor H2S (usually lower than 200ppmv), which is transformed into SO2 before being emitted.
Sulfur Recovery Unit Equipment
Ruichang is not only a total sulfur recovery solution provider, but it is also an equipment manufacturer. We are able to supply all the equipment for the SRU unit. With full control of the equipment manufacture, we can guarantee all the machinery is seamlessly integrated into any SRU proposal we design for you.
Advantages and Application Fields of Ruichang SRU System
Ruichang SRU (sulfur recovery unit) is mainly used in the petrochemical industry, commonly found in large industrial refineries. Both large oil plants, chemical plants, and power plants need to use sulfur-containing waste gas desulfurization purification technology and SRU equipment. In recent years, the market demand for sulfur recovery equipment has continued to maintain a growth rate of over 14%. This is all due to the obvious advantages of SRU recycling equipment:
- Wide application. Ruichang SRU system can generate elemental sulfur from the sulfur-containing exhaust gas. Elemental sulfur can be used in many fields and produce huge economic benefits.
- High recovery rate. Sulphur recovery unit in refinery can recover extremely high purity sulfur. The standard sulfur recovery rate is 94.5~97.5%, and the sulfur recovery rate can be increased to 99.9% through tail gas treatment.
- Energy-saving. Reliable sulfur recovery unit produced by Ruichang has low power consumption and high capacity. The maximum capacity of the SRU project can reach 150,000 tons/year or even higher.
- Environmental friendly. Ruichang SRU system can greatly reduce pollution emissions from refineries and is environmentally friendly.
Ruichang SRU Project Case Study
Ruichang is highly competent to provide a complete EPC (Engineering Procurement Construction) solution of reliable sulfur recovery unit for the petrochemical and coal chemical industry. With more than 30 years’ experience and 200 sets of the application installed, our system has been proven by numerous clients that the performance, as well as the technological standard, is equal to or even higher than those of counterpart supplier in the industry.
Currently, the largest sulphur recovery unit in refinery project we have participated in has a capacity of 150,000 tons/year. Ruichang has the strength and ability to undertake SRU projects with higher annual production capacity. The following are examples of the successful SUR projects made by Ruichang.
Project 1: Sinopec Changling Branch 50000 tons/year sulfur recycled and tail gas treatment system project
The project is the sulfur recovery and tail gas treatment system for Sinopec Changling Branch. The annual production capacity is 50,000 tons. The SRU system uses acid gas burners, and the combustion medium is acid gas and fuel gas.
| Client Name | Burner Type | Medium | Order Date | Equipment and Supply Information |
|---|---|---|---|---|
| Sinopec Changling Branch | Acid gas burner | Acid gas & fuel gas | Jan 4th | Full set sulfur recycled and tail gas treatment system |
Project 2: 55,000 tons/year SRU EPC overall project in Shanxi
The project is an SRU EPC project independently undertaken by Ruichang. The design, procurement, construction, and trial operation of the project construction are all independently completed by the company’s engineering design team. The project client is Shanxi Tiefeng Chemical Co., Ltd., with an annual output of 55,000 tons.
| Client Name | Burner Type | Medium | Order Date | Equipment and Supply Information |
|---|---|---|---|---|
| Shanxi Tiefeng Chemical Co., Ltd. | RCFS-WG0000 | Tail gas & fuel gas | Jul 6th | SRU EPC whole process equipment |
Project 3: 10,000 tons/year sulfur recovery unit of Henan Kailun Chemical Co., Ltd.
The project adopts the “three-stage Claus + selective oxidation” process, and the total sulfur recovery rate reaches 99%. The process gas is reheated by medium pressure steam and a combined catalyst is used. The project started production in June 2019 and has been running steadily ever since.
| Client Name | Project Location | Acid Gas Composition（v%） | Scale |
|---|---|---|---|
| Henan Kailun Chemical Co., Ltd. | Henan | H2S 86.7, CS2 13.3 | 1100Nm3/h |
Project 4: Anyang Yingde Gas Co., Ltd. Syngas Project 5000 tons/year sulfur recovery unit
The project adopts “three-stage conversion + selective hydrogenation + selective oxidation” super-fine Claus process. There is no additional H2 supplementation in the sulfur recovery process, and the combined catalyst is used, and the total sulfur recovery rate is greater than or equal to 99.5%. The project was put into production in 2014 and has been operating in good condition.
| Client Name | Project Location | Acid Gas Composition（v%） | Scale |
|---|---|---|---|
| Anyang Yingde Gas Co., Ltd. | Anyang | H2S 30, CO2 55, CH3OH 1.0, N2 14 | 1200Nm3/h |
