Desulphurization process

The application of 33S NMR spectroscopy to the qualitative characterization of sulphur compounds in coals and petroleum has been another subject of a certain interest.99-10 The presence of organic and inorganic sulphur derivatives in variable amounts in fuels has serious economic and environmental consequences. Coals and crude oils can be treated chemically to reduce sulphur content, and it is of fundamental importance to develop an analytical method to rapidly and accurately analyse sulphur before and after the desulphurization process. 

The hydrocarbon desulphurization process illustrates two different purposes of these analysers process control and control of wastes dumped into the atmosphere. The desulphurization process Involves two stages. In the first, sulphur is removed from the hydrocarbons by catalytic hydrogenation (Fig. 16.2) ... 

The treatment of fuels, particularly desulphurization and the removal of volatile inflammable substances belong to successful approaches providing a remarkable decrease of emissions. In the case of solid fuels such as coal, it is possible to use grading, floating, carbonization (particularly a low-temperature one) or further thermal treatments. The hydrogenation desulphurization process is highly efficient, but, it is very expensive for coal and in practice it is feasible only for the desulphurization of heating oils. 

Experimental work on H2S removal, both under actual operating conditions and with simulated coal gas, has led to the conclusion that fuel gas composition has little influence on the desulphurization process except at minimum residual concentration levels where the thermodynamic equilibrium is worsened by the presence of CO, CO2, H2O [112], With Ce02, indications are that the presence of H2O has no negative impact [113], and this seems to be also true with CUO-AI2O3 sorbents [114]. 

The mutual transformation of hydrogen sulphide and carbonyl sulphide and its role for gas desulphurization processes with zeolitic molecular sieve sorbents... 

The description in the literature of early gas desulphurization processes that utilize zeolites does not mention duly the formation of COS during the removal of H2S, if CO2 is present in the feed gas, except in a few cases, e.g., ref. [20,28,65]. Since modern desulphurization plants work in accordance with the same principles and utilize identical zeolite types, the COS formation reaction may have strong implications for the currently employed processes for desulphurization of gases by means of those sorbents. Therefore, it is necessary to investigate (i) the COS formation as dependence on the zeolite type, the type and content of cations in the sorbent, the concentration and contact time of reactants with the sorbent, the temperature and the conditions of co-adsorption (ii) the mechanism of that reaction on the sorbent with specific emphasis on its sorption and catalytic properties and (iii) to develop a mathematical model to simulate dynamic processes that proceed in adsorbers/reactors of technical dimension. This investigation should lead to novel formulations of modified zeolite sorbents and to alternatives with regard to operating conditions of sorption plants with the purpose of either minimization or maximization of the formation of COS. 

Basket centrifuges with plough discharge often have a hydraulic, variable speed drive, are of three-point support or overdriven construction (e.g. Broad-bent or Mirlees) and their diameters vary from 260 to 1500 mm (filtration areas from 0.13 to 2.9 m ). Applications of all types of basket centrifuges include separation of crystals (such as sugar where throughput rates up to 36 t/h have been reported ), nitro-cellulose, metal swarf or enamel frit, and lately also gypsum from gas desulphurization processes at coal-fired power stations. ... 

Hernandez S, Solarino L, OrseUo G, Russo N, Fino D, Saracco G et al (2008) Desulphurization process for fuel cells systems Int. J. Hydrogen Energy 33 3209-3214... 

Fine desulfurizer at room temperature. Since the end of 1980s, Imperial Chemical Industries Ltd (ICI) developed a fine desulphurization process on Hydrolyzed Zinc Oxide at room temperature. Yuhua Kong et al in Hubei Institute of Chemistry, China, developed T504 catalysts for COS hydrolysis and TlOl activated carbon fine desulfurizer successfully, and achieved fine desulphurization at room temperature, with the sulfur content below O.lmg/m in the gas after desulphurization. These desulfurizers are suitable to protect the catalysts for the methanation, ammonia synthesis and methanol synthesis. 

Fig. 7.25 The ISPRA Mk XIIIA pilot plant flue-gas desulphurization process at the Saras refinery, Sardinia. (Courtesy Centro Commune di Ricerca, ISPRA.)...

The procedure that has been discussed will be applied to a desulphurization process (Fig. 33.5). points will be discussed simultaneously. 

Table 33.5. Interaction table showing power and speed of control for the desulphurization process.

Donovan, J. J., and Laroche, K. J., 1981, Two Approaches to Effluent Treatment of a Coke-Oven Gas Desulphurization Process, paper presented at 64th Chemical Conference and Exhibition, Chemical Institute of Canada, May 31-June 3. 

---