Cracking reactions sulfur contents

Naphtha desulfurization is conducted in the vapor phase as described for natural gas. Raw naphtha is preheated and vaporized in a separate furnace. If the sulfur content of the naphtha is very high, after Co—Mo hydrotreating, the naphtha is condensed, H2S is stripped out, and the residual H2S is adsorbed on ZnO. The primary reformer operates at conditions similar to those used with natural gas feed. The nickel catalyst, however, requires a promoter such as potassium in order to avoid carbon deposition at the practical levels of steam-to-carbon ratios of 3.5—5.0. Deposition of carbon from hydrocarbons cracking on the particles of the catalyst reduces the activity of the catalyst for the reforming and results in local uneven heating of the reformer tubes because the firing heat is not removed by the reforming reaction. 

The specifically formulated CGP-1 catalyst plays a vital role in the MIP-CGP process. Unique catalyst design, such as metal promoted MFl zeolite, phosphorus modified Y zeolite, and a novel matrix with excellent capability to accommodate coke [12] were involved to ensure the primary cracking and secondary reactions to proceed within a defined path. The commercial trial results of the MIP-CGP process in SINOPEC Jiujiang Company showed that, in combination with CGP-1 catalyst, the propylene yield was 8.96 wt%, which increased by more than 2.6% as compared with FCC process. The light ends yield and slurry yield are basically equal. The olefin content of the gasoline produced by MIP-CGP process was 15.0 v%, which was 26.1% lower than that of FCC gasoline. The sulfur content of gasoline was decreased from 400 to 270 pg/g. 

Oxide formation leads to a decrease in the overall oxidation rate, according to Eq. (3). The value of in this equation [which is the same as in the crack propagation rate Eq. (5)] varies with the alloy chemistry [e.g., chromium content for a denuded grain boundary of type 304 stainless steel, or sulfur content for low-alloy steels (Fig. 11)], electrode potential, and anionic activity, and this can be related to e.g., solid-state oxide growth, dissolution-precipitation reactions, and oxide breakdown [1,11]. Thus, all of the parameters in Eq. (5), apart fi om can be quantified for the crack tip system, which can, in turn, be related to de able or measurable bulk system conditions. 

Residual oils might be gasified or cracked over calcined dolomite with recovery of elemental sulfur in a cyclic process incorporating Reaction 1. A version of this process may be useful in providing sulfur-free fuel to existing power station boilers in communities which impose restrictions on S02 content of stack gases. 

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