Sulfite process

sulfitesulfite pulpingsulphite process
The concentrated brown liquor is burned in a recovery boiler, producing magnesium oxide and sulfur dioxide, both of which are recovered from the flue gases. Magnesium oxide is recovered in a wet scrubber to give a slurry of magnesium hydroxide. This magnesium hydroxide slurry is then used in another scrubber to absorb sulfur dioxide from the flue gases producing a magnesium bisulfite solution that is clarified, filtered and used as the pulping liquor. Sodium-based processes use a recovery system similar to that used in the kraft recovery process, except that there is no "lime cycle".


boilerssteam generatortop feed
The steam jet oriented in the direction of flue gas flow induces flue gases into the stack and allows for a greater flue gas velocity increasing the overall draught in the furnace. This method was common on steam driven locomotives which could not have tall chimneys. The second method is by simply using an induced draught fan (ID fan) which removes flue gases from the furnace and forces the exhaust gas up the stack. Almost all induced draught furnaces operate with a slightly negative pressure. Mechanical forced draught is provided by means of a fan forcing air into the combustion chamber.


Black liquor. Gasification. Second generation biofuels. Kraft process. Sulfite process. Chemrec. Environmental Technologies Fund. Volvo Technology Transfer. Nykomb Synergetics. VantagePoint Venture Partners.

Fossil fuel power station

coal-fired power stationcoal power plantfossil fuel power plant
Biomass power station. Boiler (power generation). Coal analyzer. Coal mining. Combined heat and power. Cooling tower system. Environmental impact of the coal industry. Flue gas stacks. Fossil fuel phase-out. Geothermal power. Global Energy Monitor. Global warming. Greenhouse gas. List of coal power stations. List of thermal power station failures. Mercury vapor turbine. Natural gas. Power station. Relative cost of electricity generated by different sources. Renewable energy power station. Steam reforming. Steam turbine. Thermal power station. Water-tube boiler. Steam: Its Generation and Use (2005). 41st edition, Babcock & Wilcox Company, ISBN: 0-9634570-0-4.


coal seamcoal industrycoal-fired
To keep global warming below 1.5°C or 2°C hundreds, or possibly thousands, of coal-fired power plants will need to be retired early. "Clean" coal technology usually addresses atmospheric problems resulting from burning coal. Historically, the primary focus was on SO 2 and NO x, the most important gases which caused acid rain; and particulates which cause visible air pollution, illness and premature deaths. SO 2 can be removed by flue-gas desulfurization and NO 2 by selective catalytic reduction (SCR). Particulates can be removed with electrostatic precipitators. Although perhaps less efficient wet scrubbers can remove both gases and particulates.


particulate matterparticulatefine particulate matter
About 40% of the population lives in apartments, 80% of which are supplied with central heating systems from 3 combined heat and power plants. In 2007, the power plants consumed almost 3.4 million tons of coal. The pollution control technology is in poor condition. The other 60% of the population reside in shantytowns (Ger districts), which have developed due to the country's new market economy and the very cold winter seasons. The poor in these districts cook and heat their wood houses with indoor stoves fueled by wood or coal.


Incineration has a number of outputs such as the ash and the emission to the atmosphere of flue gas. Before the flue gas cleaning system, if installed, the flue gases may contain particulate matter, heavy metals, dioxins, furans, sulfur dioxide, and hydrochloric acid. If plants have inadequate flue gas cleaning, these outputs may add a significant pollution component to stack emissions. In a study from 1997, Delaware Solid Waste Authority found that, for same amount of produced energy, incineration plants emitted fewer particles, hydrocarbons and less SO 2, HCl, CO and NO x than coal-fired power plants, but more than natural gas–fired power plants.


Some of the largest-scale chemicals are produced via catalytic oxidation, often using oxygen. Examples include nitric acid (from ammonia), sulfuric acid (from sulfur dioxide to sulfur trioxide by the contact process), terephthalic acid from p-xylene, acrylic acid from propylene or propane and acrylonitrile from propane and ammonia. Many other chemical products are generated by large-scale reduction, often via hydrogenation. The largest-scale example is ammonia, which is prepared via the Haber process from nitrogen. Methanol is prepared from carbon monoxide or carbon dioxide. Bulk polymers derived from ethylene and propylene are often prepared via Ziegler-Natta catalysis.


gaseous gaseous state of waterPC
Nuclear power—and power plants use steam to generate electricity. Oxyhydrogen. Psychrometrics—moist air/vapor mixtures, humidity and air conditioning. Steam locomotive. Steamed.

Thermal power station

thermal power plantthermal powerthermal power plants
Biochar processing in thermal power stations. Cogeneration aka combined heat and power. Cooling tower. Cost of electricity by source. Energy crop. Flue-gas stack. Fossil fuel power station. Geothermal power. Integrated gasification combined cycle. Iron powder. List of largest power stations. List of thermal power station failures. Nuclear power. Power station. Surface condenser. Water-tube boiler. Thermal Power Plant:Indian Context. Conventional coal-fired power plant. Power station diagram. Power Plant Reference Books. Steam jet ejectors. Steam jet ejector performance guidelines. and video lectures by S. Banerjee on "Thermal Power Plants".

District heating

district heatsteamdistrict energy
A simple thermal power station can be 20–35% efficient, whereas a more advanced facility with the ability to recover waste heat can reach total energy efficiency of nearly 80%. Some may approach 100% based on the lower heating value by condensing the flue gas as well. Waste heat from nuclear power plants is sometimes used for district heating. The principles for a conventional combination of cogeneration and district heating applies the same for nuclear as it does for a thermal power station. Russia has several cogeneration nuclear plants which together provided 11.4 PJ of district heat in 2005.

Pulp (paper)

pulpwood pulppaper pulp
The competing chemical pulping process, the sulfate, or kraft, process, was developed by Carl F. Dahl in 1879; the first kraft mill started, in Sweden, in 1890. The invention of the recovery boiler, by G.H. Tomlinson in the early 1930s, allowed kraft mills to recycle almost all of their pulping chemicals. This, along with the ability of the kraft process to accept a wider variety of types of wood and to produce stronger fibres, made the kraft process the dominant pulping process, starting in the 1940s. Global production of wood pulp in 2006 was 175 million tons (160 million tonnes).

Waste-to-energy plant

waste-to-energyplantwaste-to-energy incinerators
Waste-to-energy plants are designed to reduce the emission of air pollutants in the flue gases exhausted to the atmosphere, such as nitrogen oxides, sulfur oxides and particulates, and to destroy pollutants already present in the waste, using pollution control measures such as baghouses, scrubbers, and electrostatic precipitators. High temperature, efficient combustion, and effective scrubbing and controls can significantly reduce air pollution outputs. Burning municipal waste does produce significant amounts of dioxin and furan emissions to the atmosphere as compared to the smaller amounts produced by burning coal or natural gas.


burningignitionincomplete combustion
Such devices are required by environmental legislation for cars in most countries and may be necessary to enable large combustion devices, such as thermal power stations, to reach legal emission standards. The degree of combustion can be measured and analyzed with test equipment. HVAC contractors, firemen and engineers use combustion analyzers to test the efficiency of a burner during the combustion process. In addition, the efficiency of an internal combustion engine can be measured in this way, and some U.S. states and local municipalities use combustion analysis to define and rate the efficiency of vehicles on the road today.

Pulp mill

pulpPulp and paper millground wood pulp mill
The extracted liquid, known as black liquor in the kraft process, and red or brown liquor in the sulfite processes, is concentrated, burned and the sodium and sulphur compounds recycled in the recovery process. Lignosulphonates are a useful byproduct recovered from the spent liquor in the sulfite process. The clean pulp (stock) can be bleached in the bleach plant or left unbleached, depending on the end use. The stock is sprayed onto the pulp machine wire, water drains off, more water is removed by pressing the sheet of fibres, and the sheet is then dried. At this point the sheets of pulp are several millimetres thick and have a coarse surface: it is not yet paper.

Flue-gas stack

flue gas stackchimneychimneys
Many such equipment items use large fans or blowers to accomplish the same objectives, namely: the flow of combustion air into the combustion chamber and the flow of the hot flue gas out of the chimney or stack. A great many power plants are equipped with facilities for the removal of sulfur dioxide (i.e., flue-gas desulfurization), nitrogen oxides (i.e., selective catalytic reduction, exhaust gas recirculation, thermal deNOx, or low NOx burners) and particulate matter (i.e., electrostatic precipitators). At such power plants, it is possible to use a cooling tower as a flue gas stack.


scrubbingair scrubberexhaust gas scrubber
Flue-gas desulfurization. Flue-gas condensation. Mercury (element). Mercury cycle. Oil desulfurization. Electrostatic precipitator. BS4994 Chemical Process Plant Equipments in FRP. Catalytic converter. Wet scrubber. Baffle spray scrubber. Ejector venturi scrubber. Liquid-to-gas ratio. Mechanically aided scrubber. Spray tower. Spray nozzle. Stripping (chemistry). Venturi scrubber. Jesper Jarl Fanø (2019). Enforcing International Maritime Legislation on Air Pollution through UNCLOS. Hart Publishing.


Also, can be used in making of biodegradable plastic along with cellulose as an alternative to hydrocarbon made plastics if lignin extraction is achieved through a more environmentally viable process than generic plastic manufacturing. Lignin removed by the kraft process is usually burned for its fuel value, providing energy to power the mill. Two commercial processes exist to remove lignin from black liquor for higher value uses: LignoBoost (Sweden) and LignoForce (Canada). Higher quality lignin presents the potential to become a renewable source of aromatic compounds for the chemical industry, with an addressable market of more than $130bn.

Natural gas

Natural gas is also well suited for a combined use in association with renewable energy sources such as wind or solar and for alimenting peak-load power stations functioning in tandem with hydroelectric plants. Most grid peaking power plants and some off-grid engine-generators use natural gas. Particularly high efficiencies can be achieved through combining gas turbines with a steam turbine in combined cycle mode. Natural gas burns more cleanly than other fuels, such as oil and coal. Because burning natural gas produces both water and carbon dioxide, it produces less carbon dioxide per unit of energy released than coal, which produces mostly carbon dioxide.


synthesis gassynthetic gascoal gas
Integrated gasification combined cycle. Partial oxidation. Reformer sponge iron cycle. Syngas fermentation. Underground coal gasification. Fischer Tropsch archive.

White liquor

These additional components are considered inert in the Kraft process, except sodium carbonate that contributes to a lesser extent. The chemical composition and properties of the white liquor are calculated as total alkali, active alkali, effective alkali, sulfidity, causticity and reduction. The Kraft cooking liquor (white) is used to extract the lignin and break down the cellulose composition of wood chips into usable pulp. The white (cooking) liquor becomes black liquor and is sent to the recovery process. *Pulp & Paper chemicals

Sodium sulfide

Na 2 Ssodium monosulfidesodium sulfide nonahydrate
When heated with oxygen and carbon dioxide, sodium sulfide can oxidize to sodium carbonate and sulfur dioxide: :2 Na 2 S + 3 O 2 + 2 → 2 Na 2 CO 3 + 2 SO 2 Oxidation with hydrogen peroxide gives sodium sulfate: :Na 2 S + 4 H 2 O 2 → 4 + Na 2 SO 4 Upon treatment with sulfur, polysulfides are formed: :2 Na 2 S + S 8 → 2 Na 2 S 5 Sodium sulfide is primarily used in the kraft process in the pulp and paper industry.

Sulfur dioxide

sulphur dioxideSO 2 SO2
Sulfur dioxide emissions are a precursor to acid rain and atmospheric particulates. Due largely to the US EPA's Acid Rain Program, the U.S. has had a 33% decrease in emissions between 1983 and 2002. This improvement resulted in part from flue-gas desulfurization, a technology that enables SO 2 to be chemically bound in power plants burning sulfur-containing coal or oil. In particular, calcium oxide (lime) reacts with sulfur dioxide to form calcium sulfite: Aerobic oxidation of the CaSO 3 gives CaSO 4, anhydrite. Most gypsum sold in Europe comes from flue-gas desulfurization. Sulfur can be removed from coal during burning by using limestone as a bed material in fluidized bed combustion.


Piteå, SwedenPiteaBiŧon
Chemrec operates a black liquor gasifier and the world's first BioDME production facility, SunPine has pioneered a renewable diesel process technology using crude tall oil as feedstock, and ETC (Energy Technology Centre in Piteå) is a research and development center for renewable fuels with focus on combustion, gasification and biorefining processes. The Piteå IF football team is playing in the fourth highest Swedish division, Division 2 for men; and the Piteå IF ladies team is for their first time playing in the highest league in football, Damallsvenskan. Ice hockey is the big sport in town, even though Piteå HC only plays in the third-highest league (Division I) in Sweden.

Babcock & Wilcox

B&WBabcockBabcock & Wilcox Company
Historically, the company is best known for their steam boilers and later as a provider of emissions control equipment, waste-to-energy facilities and aftermarket parts and services for a host of industries. The company was founded in 1867 in Providence, Rhode Island by partners Stephen Wilcox and George Babcock to manufacture and market Wilcox’s patented water-tube boiler.