Overview of Process Modeling Software: Utilizing Alternative Fuels in Cement Plant for Air Pollution Reduction

The use of process systems engineering tools, such as process modeling software enable the alternative generation of more efficient and sustainable processes. This paper presents the simulation of cement process using alternative fuels to replace coal.  The process modeling is performed using Aspen HYSYS. Simulation results revealed that the substitution of fuel oil, natural gas and palm kernel shell for coal had a significant contribution for emission reduction in cement industry. The emissions for the base case scenario found to be 40,317 kg/h CO2, 806 kg/h NO2 and 146.8 kg/h SO2. Utilizing fuel oil mitigated 22% of CO2 and 92% of NO2 but increased 232% of SO2 emissions. Altering coal to palm kernel shell resulted in 46.16% of CO2, 73% of NO2 and 68% of SO2 emission reduction. In the best case 45.64 % reduction of CO2 emissions was achieved by replacing coal to natural gas and neither NO2 nor SO2 was generated.Key words: Cement plant; Process simulation; Aspen HYSYS; Alternative fuels; Air pollution reductio

Techno-economical and Environmental Study of Utilizing Alternative Fuel and Waste Heat Reuse in a Cement Plant

In this work, a cement plant was simulated to estimate heat losses and pollution emission in the process. Also, a waste heat recovery system was introduced to use two main sources of heat losses, i.e. flue gas and hot air streams and produce steam and power. Moreover, the use of natural gas as an alternative to the current energy source, fuel oil, was studied in two cases, associated with and without waste heat recovery system. Results showed that 34.28% of initial energy was lost in the base case, 48% of which is from flue gas and hot vent air streams. Also, changing the fuel source from fuel oil to natural gas results in CO2 emission rate to decrease from 118,693 to 115,367 kg/hr, and emission of NO2 and SO2 was reduced to nearly 100%. In addition to environmental benefits, economical analyses suggest the use of waste heat recovery system as well as change of fuel for this plant.Key words: Cement plant; Waste heat recovery; Alternative fuel; HYSYS simulation; Air pollution reductio

Integrated Hazard Identification (IHI): A Quick Accident Analysis and Quantification Method for Practitioners

There are many techniques for hazard identification and are divided into shortcut, standard and advanced techniques. Among these, HAZOP and What-If techniques are mostly engaged by practitioners in the chemical process industry. Both of these have certain advantages and limitations, i.e., HAZOP is structured, and what-if covers broad range of scenarios. There is no hazard identification method, which can cover a broad range of scenarios and is structured in nature. For this purpose, a new technique namely integrated hazard identification (IHI) is proposed in this article that integrates HAZOP and What-If. The methodology is demonstrated via hazard identification study of urea synthesis section. Risk ranking is used to sort out the worst-case scenario. This worst-case scenario is further studied in detail for quantification that is performed using the ALOHA software. This quantification has assisted to detect ammonia concentrations in nearby control room and surroundings for worst-case scenario. It is revealed that if ammonia pump is not stopped within 10 minutes, concentration inside and outside the control room may reach to 384 ppm and 2630 ppm, compared to 1100 ppm (AEGL-3). Thus the proposed method would be easy, time saving and covers more details and would be handy for practicing engineers working in different chemical process industries

A novel design for green and economical cement manufacturing

This paper presents new design of pyro-processing unit in a cement factory. In this case decomposition reactions have been separated from other reactions which result in pure carbon dioxide production. Decomposition reactions take place in calciner without fuel consumption by utilizing a hot CO2 stream as heat carrier and exhaust gases have been employed to produce steam and power. As result of such novelties new process can significantly reduce 66% of CO2 emission and 2.3% of energy consumption compared to the existing process. Moreover proposed design demonstrated remarkable environmental advantages against some relevant studies and processes. As far as process economy is concerned, novel design can annually achieve 20.7 million USD gross incomes compared to the base case

Magnesium Leachability of Mg-Silicate Peridotites: The Effect on Magnesite Yield of a Mineral Carbonation Process

The aim of this study was to increase feedstock availability for mineral carbonation. Acid dissolution and carbonic acid dissolution approaches were used to achieve higher Mg extractions from peridotites. Acid dissolution studies of raw dunite, heat-activated dunite, heat-transformed dunite, and twin sister dunite have not been reported in the literature. Heat-activated dunite is more reactive as compared to heat-transformed dunite, raw dunite, and twin sister dunite. The fraction of magnesium extracted from heat-activated dunite was 57% as compared to 18% from heat-transformed dunite, 14% from raw dunite, and 11% from twin sister dunite. Similarly, silicon and iron extractions were higher for heat-activated dunite compared to that of heat-transformed dunite, raw dunite, and twin sister dunite. Materials rich in forsterite (twin sister dunite and heat-transformed dunite) showed preferential Mg release and exhibited incongruent dissolution similar to that of forsterite. Heat-activated dunite (amorphous magnesium silicate rich) on the other hand behaved differently and showed congruent dissolution. Olivine did not dissolve under carbonic acid dissolution (with concurrent grinding) and acidic conditions. Under carbonic acid dissolution with concurrent grinding conditions, olivine was partially converted into nanometer sized particles (d10 = 0.08 µm) but still provided 16% Mg extraction during 4 h of dissolution