Processes and compositions are provided for decreasing emissions of mercury upon combustion of fuels such as coal. Various sorbent compositions are provided that contain components that reduce the level of mercury and/or sulfur emitted into the atmosphere upon burning of coal. In various embodiments, the sorbent compositions are added directly to the fuel before combustion; are added partially to the fuel before combustion and partially into the flue gas post combustion zone; or are added completely into the flue gas post combustion zone. In preferred embodiments, the sorbent compositions comprise a source of halogen and preferably a source of calcium. Among the halogens, iodine and bromine are preferred. In various embodiments, inorganic bromides make up a part of the sorbent compositions.

Reducing mercury emissions from the burning of coal

A system and method for providing continuous measurement and control of a combustion device by altering the fuel composition delivered thereto. The system includes devices for sensing related information, such as fuel characteristics, combustion characteristics, or other device characteristics, and controlling the performance of the combustion device based on the sensed information. Performance control occurs via addition of one or more additives to the fuel to adjust combustion characteristics. Via such sensing and performance control, consistent combustion device performance may be maintained, despite varying fuel characteristics. In one variation, sensing occurs for the fuel delivered to the combustion device, and one or more additives are added to the fuel, based on the composition and flow rate for the fuel. In another variation, characteristics of the combustion device in operation, such as flame characteristics, are sensed and used to adjust fuel characteristics via iterative addition of one or more additives.

System and method for flame stabilization and control

Unburned particulate matter is removed from a combustion gas stream by adding a conditioning agent to modify the resistivity of the particulate matter and passing the conditioned combustion gas stream through an electrostatic precipitator whose precipitating elements are energized with an intermittent applied voltage. The addition of conditioning agent and the precipitating voltage signal are mutually optimized. A controller receives measurement signals from sensors that monitor the total flow rate of particulate matter in the gas stream before the electrostatic precipitation treatment, and the concentration of particulate matter in the gas stream after the treatment. Performance of the system may be optimized according to selected combinations of variables.

Removal of particulate matter from combustion gas streams

The sulfur trioxide in the combustion gas stream of a power plant is reacted with injected ammonia to produce a solid ammonium sulfate that is captured, and not released to the atmosphere. A feedforward signal indicative of the total mass flow of sulfur trioxide is determined as the product of the measured boiler load and the sulfur trioxide content of the combustion gas, as measured prior to the addition of ammonia. The ammonia mass flow injection rate is preferably at a normal stoichiometric ratio of from about 1.0 to about 1.1 relative to the sulfur trioxide mass flow rate (that is, from about 2.0 to about 2.2 times the molar mass flow rate of the sulfur trioxide), avoiding the production of ammonia bisulfate. The ammonia content of the combustion gas stream is measured downstream of the location at which ammonia is added. Based upon this feedback measurement, the amount of ammonia added is adjusted to be just sufficient to react with all of the sulfur trioxide, but not in such excess as to be environmentally detrimental.

Reduction of acidic emissions from combustion of sulfur-laden fuels

The present disclosure is directed to the use of elemental or speciated iodine and bromine to control total mercury emissions.

Method and system for controlling mercury emissions from coal-fired thermal processes

The method of operation of a boiler system to which an additive is to be fed at a controlled rate and in which the optimal additive rate depends upon a plurality of changing parameters of the boiler system, in which the relationship between each of those parameters and the optimal additive feed rate is determined, the relevant parameters are sensed during the operation of the system, their effects on optimum additive feed are computed in accordance with said relationships and combined on a continuous basis to produce a control signal representative of the desired rate of additive feed, and controlling the additive feed in accordance therewith, all preferably continuously.

Method for controlling additive feed in a boiler system

A method for minimizing corrosion and the build-up of deposits on surfaces of a flue-gas system exposed to moist substances and elevated temperatures, and particularly those surfaces which are used to convey other additives to the system and the surfaces of gas/gas heaters which receive the output from scrubbers, which method involves adding to the system, particularly in those conduits and at the surfaces of the gas/gas heater, generally inert bulking agents such as perlite and vermiculite in expanded form, such agents, apparently by acting under the operating conditions to which they are subjected to retain substantial quantities of water without becoming dissolved, accomplishing the desired results.

Use of expanded agents for minimizing corrosion and build-up of deposits in flue-gas systems

A method for minimizing corrosion and the build-up of deposits on surfaces of a flue-gas system exposed to moist substances and elevated temperatures, and which includes a desulfurizer and heat transfer means communicating with the desulfurizer, said method involving adding to the system at the heat transfer means a readily water soluble alkaline substance such as sodium hydroxide in amounts sufficient to produce with said flue-gas in said heat transfer means a minimum pH of about 5, preferably 7 or higher.

Ira Kukin

Papers

Method for controlling additive feed in a boiler system

Use of expanded agents for minimizing corrosion and build-up of deposits in flue-gas systems

Minimizing corrosion and build-up in a flue-gas system including a desulfurizer