Heptane-insoluble conversion

A 178-hr hydrotreating run was made, during which the heptane-insoluble conversion dropped 10%. Results obtained at 54-78 hr on stream are given in Table II. Mass balance, chemical analysis, and fractionation gave the fuel product and hydrogen distributions shown in Table III. 

Thermal Instability of Hydrorefined Products. Thermal instability of hydrorefined product from the reconstituted feed was observed for both Ni-W and Ni-Mo. Comparing the conversion of heptane insolubles for undistilled and distilled materials showed evidence of considerable polymerization for the distilled material. Heptane insolubles conversion for undistilled product from Ni-W was higher than for distilled product as seen in Figure 14. Distilling the product from the 725°F balance reduced the heptane-insoluble conversion from 30% to 16%. For Ni-Mo the reduction for the heptane insolubles was on the same order of magnitude, approximately a 10% decrease in the heptane-insolubles conversion. 

Figure 14. Heptane-insoluble conversion vs. temperature. Total undistilled sample (M), Ni-Mo ( ), Ni-W. Bottoms from distillation (D),...

There are several possible flow scheme variations involved for this process. It can operate as an independent unit or be used in conjunction with a thermal conversion unit (Figure 9-25). In this configuration, hydrogen and a vacuum residuum are introduced separately to the heater, and mixed at the entrance to the reactor. T o avoid thermal reactions and premature coking of the catalyst, temperatures are carefully controlled and conversion is limited to approximately 70% of the total projected conversion. The removal of sulfur, heptane-insoluble materials, and metals is accomplished in the reactor. The effluent from the reactor is directed to the hot separator. The overhead vapor phase is cooled, condensed, and the hydrogen separated from there is recycled to the reactor. 

Effect of Coal Rank and Solvent Source on Conversions and Heptane-Insoluble Product Compositions... 

Primary coal liquefaction products from three processes— solvent-refined coal, Synthoil, and H-Coal—were hydrotreated. Upgrading was measured in terms of the decrease in heptane and benzene insolubles, the decrease in sulfur, nitrogen, and oxygen, and the increase in hydrogen content. Hydrotreating substantially eliminated benzene insolubles and sulfur. An 85% conversion of heptane insolubles and an 80% conversion of nitrogen was obtained. Catalyst stability was affected by metals and particulates in the feedstocks. 

Hydrotreatment was carried out over a commercial UOP black oil conversion catalyst in bench-scale units of 200-800 mL catalyst capacity. Temperature range was 375°-450°C and the pressure range was 2000-3000 psig. Weight hourly space velocity (WHSV) varied from 0.1 to 1.0 depending on the heptane-insoluble content of the feed. A flow diagram of a typical plant is shown in Figure 1. The stripper bottoms usually... 

The heptane-insoluble content of the composite product was 9.76%, representing an 89% conversion. The variation of heptane insolubles with time is shown in Figure 2. Initial conversion of heptane insolubles was 94% while final conversion was 86%. 

Table VI recapitulates the relative response of Synthoil and SRC to hydrotreating in terms of percentage conversion of heptane insolubles, as reported in Table II. Conversion of heptane insolubles was substantially greater in the case of SRC. While the Synthoil was processed at a higher space velocity, the throughput rate of Synthoil feed heptane insolubles was only half that of the SRC feed heptane insolubles. Temperature in the Synthoil run was 5°-10°C lower than in the SRC run.

This comparison is reinforced by a comparison of Synthoil with UOP-filtered SRC filter feed. Figure 4 illustrates the response of the two stocks to hydrotreating as a function of pressure and space velocity. The temperature range of the experiments was 9°C. Conversion of SRC heptane insolubles was first order up to 98%, and the effect of pressure was relatively small. Conversion of Synthoil heptane insolubles never exceeded 80% under comparable conditions, and it was strongly dependent on pressure. 

Therefore, in a mixture as complex as petroleum, the reaction processes can only be generalized because of the difficulties in analyzing not only the products but also the feedstock as well as the intricate and complex nature of the molecules that make up the feedstock. The formation of coke from the higher molecular weight and polar constituents of a given feedstock is detrimental to process efficiency and to catalyst performance. One method by which the process chemistry can be rationalized is to separate the resid and its conversion products into fractions using solubility/ insolubility in volatile liquids as well as adsorption/ desorption on solids. In this way a number of resids and resid conversion products were separated into coke (toluene insoluble), asphaltenes (toluene soluble/ n-heptane insoluble), resins (n-heptane soluble, adsorbs on alumina), aromatics (n-heptane soluble, does not adsorb on alumina), and saturates (n-heptane soluble, does not adsorb on alumina). 

Vinyl fluoride monomer exhibits solubility in a variety of organic solvents, e.g., the lower alcohols, ethers, mono- and dinitriles, butyrolactone, liquid amides such as diethylformamide [6], and heptane [38]. As mentioned before, the polymer is generally quite insoluble at ordinary temperatures. At temperatures in the range of 100 C, some of these compoimds dissolve the polymer. During the polymerization of vinyl fluoride, one would, therefore, expect to find that the polymer precipitates as it forms. Solvents also tend to act as chain-transfer agents which yield products of lower molecular weights than those formed in the absence of solvents. Procedure 2-2 shows the effect of a solvent on the intrinsic viscosity and on the overall conversion. Since the procedure is patented it is given here only to illustrate the procedure. 

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