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Qualitative Chemical Analysis
Published in Steven L. Hoenig, Basic Chemical Concepts and Tables, 2019
Ammonium sulfide (colorless):3M. Treat 200ml of conc. NH4OH with H2S until saturated, keeping the solution cold. Add 200ml of conc. NH4OH and dilute of 1 liter.6N. Saturate 6N ammonium hydroxide (40ml conc. ammonia solution +60ml H2O) with washed H2S gas. The ammonium hydroxide bottle must be completely full and must be kept surrounded by ice while being saturated (about 48 hours for two liters). The reagent is best preserved in brown, completely filled, glass-stoppered bottles.Ammonium sulfide (yellow):
Groundwater Cleanup and Remediation
Published in David H.F. Liu, Béla G. Lipták, Paul A. Bouts, Groundwater and Surface Water Pollution, 2019
David H.F. Liu, Béla G. Lipták, Paul A. Bouts
Hypochlorite is used in drinking water and municipal wastewater systems for the treatment and control of algae and biofouling organisms (U.S. EPA 1985b). In industrial waste treatments, hypochlorite is used for the oxidation of cyanide, ammonium sulfide, and ammonium sulfite (Huibregts and Kastman 1979). Sodium hypochlorite solutions at concentrations of 2500 mg/l are also used for the detoxification (by oxidation) of cyanide contamination from indiscriminate dumping (Farb 1978). However, because the principal products from chlorination of organic contaminants are chlorinated organics which can be as much of a problem as the original compound, hypochlorite treatment is limited.
Special Catalytic Reforming Topics
Published in Soni O. Oyekan, Catalytic Naphtha Reforming Process, 2018
The first significant negative impact of hydrogen chloride after the reactors is fouling and corrosion of combined feed effluent exchanges, condensers, piping, recycle gas compressors, and stabilizers. Fouling is due to ammonium chloride, ammonium sulfide, and bisulfide salt deposition in separators, condensers, debutanizer trays, debutanizer overhead, and condensers. Ammonia is formed from the residual organic nitrogen compounds in the feed to the catalytic reformer. Hydrogen chloride and hydrogen sulfide react with ammonia to form salts in the cooler areas of the product separation section. Ammonium salt formation reactions are shown in Figure 8.21.
Fouling Detection in Industrial Heat Exchanger Using Number of Transfer Units Method, Neural Network, and Nonlinear Finite Impulse Response Models
Published in Heat Transfer Engineering, 2022
Željka Ujević Andrijić, Nenad Bolf, Nikola Rimac, Adriana Brzović
The heat exchanger (E-007) of interest is located in the integrated hydrotreatment and hydrocracking plant, which examined segment is shown in Figure 1. Typical piping and instrumentation diagram symbols (process measurements and control loops) for examined segment are also seen in Figure 1. LI and LIC indicate Level Indicator and Level Indicator and Controller, FC and FIC indicate Flow Indicator and Flow Indicator and Controller, PI and PIC indicate Pressure Indicator and Pressure Indicator and Controller, and TI and TIC indicate Temperature Indicator and Temperature Indicator and Controller. Numbering under FIC and TI shown in Figure 1 represents the control loop number or instrument number. The hydrocracking process starts with the preheating of a diesel product coming from the fractionation section. This raw material then enters heat exchangers where it gets additionally heated by reactor effluents. It then enters the furnace, to be heated to the target temperature. The hydrocracker reactor converts raw material inputs into diesel and light products while removing sulfur, hydrogen and metals. The reactor effluent is used for the production of high-pressure steam E-006, shown in Figure 1. The cooled reactor effluent enters the hot high-pressure separator V-005 (HHPS). The input flow is separated into hydrogen-rich steam and liquefied hydrocarbons. Hot steam from the HHPS, cooled and partially condensed by preheating recycled gas from the reactor first in the heat exchanger E-010 and followed by the heat exchanger of interest E-007 is shown in Figure 1. Partially condensed stream then flows into the HHPS vapor air cooler (EA-008). During the cooling of HHPS steam, ammonium bisulfide salt precipitation occurs in heat exchanger pipes. Ammonia and hydrogen sulfide, formed in the reactor from sulfur and nitrogen in the feed, combine to form solid ammonium bisulfide. These solids can deposit along the air cooler tubes, thus reducing heat transfer efficiency. Special nozzles are installed in the exchangers that occasionally wash the deposits with water.