cement

[Richard D + 86]

Cement manufacture produces carbon dioxide from decomposition of calcium carbonate and also from the combustion of fuel that is burned to drive that endothermic decomposition. I suggest feeding briquettes of limestone powder and coal powder into the robust Lurgi gasifier where it could be gasified under pressure with oxygen and steam. The briquettes would be bound together with a little cement. The coal would burn and its ash would react with the limestone to give cement clinker. Water-gas shift would convert any carbon monoxide in the product gas into carbon dioxide and hydrogen by reaction with steam. The gas would then contain a large proportion of carbon dioxide,much of which could be condensed to liquid by chilling. The remaining gas could be burned in gas turbines to produce power. The clinker would have to be discharged dry,a technology which is already on offer. Calcium is a catalyst for the coal gasification reaction,increasing the reaction rate by several times. The terrible dust nuisance from conventional cement works would be largely avoided.

[KeyboardWarrior + 527]

Stealing this.

😂

Seriously though, that seems like a really good idea. I would take that down and keep it a secret. 

Edited March 6, 2020 by KeyboardWarrior

[KeyboardWarrior + 527]

On 3/3/2020 at 9:38 AM, Richard D said:

Cement manufacture produces carbon dioxide from decomposition of calcium carbonate and also from the combustion of fuel that is burned to drive that endothermic decomposition. I suggest feeding briquettes of limestone powder and coal powder into the robust Lurgi gasifier where it could be gasified under pressure with oxygen and steam. The briquettes would be bound together with a little cement. The coal would burn and its ash would react with the limestone to give cement clinker. Water-gas shift would convert any carbon monoxide in the product gas into carbon dioxide and hydrogen by reaction with steam. The gas would then contain a large proportion of carbon dioxide,much of which could be condensed to liquid by chilling. The remaining gas could be burned in gas turbines to produce power. The clinker would have to be discharged dry,a technology which is already on offer. Calcium is a catalyst for the coal gasification reaction,increasing the reaction rate by several times. The terrible dust nuisance from conventional cement works would be largely avoided.

Two limiting factors: Probably not enough coal ash to produce a significant amount of cement. Water gas shift probably wouldn't occur if there's oxygen present: The carbon monoxide would much prefer the burning option. 

[Richard D + 86]

Please see US patent 4439210 for gasification of coal with calcium carbonate.

[Sebastian Meana + 278]

On 3/3/2020 at 12:38 PM, Richard D said:

Cement manufacture produces carbon dioxide from decomposition of calcium carbonate and also from the combustion of fuel that is burned to drive that endothermic decomposition. I suggest feeding briquettes of limestone powder and coal powder into the robust Lurgi gasifier where it could be gasified under pressure with oxygen and steam. The briquettes would be bound together with a little cement. The coal would burn and its ash would react with the limestone to give cement clinker. Water-gas shift would convert any carbon monoxide in the product gas into carbon dioxide and hydrogen by reaction with steam. The gas would then contain a large proportion of carbon dioxide,much of which could be condensed to liquid by chilling. The remaining gas could be burned in gas turbines to produce power. The clinker would have to be discharged dry,a technology which is already on offer. Calcium is a catalyst for the coal gasification reaction,increasing the reaction rate by several times. The terrible dust nuisance from conventional cement works would be largely avoided.

If you have a lot of energy recycling concrete makes sense

[Eric Gagen + 713]

On 3/6/2020 at 5:34 PM, KeyboardWarrior said:

Two limiting factors: Probably not enough coal ash to produce a significant amount of cement. Water gas shift probably wouldn't occur if there's oxygen present: The carbon monoxide would much prefer the burning option. 

There is plenty of coal and coal ash.  The main problem is that coal is a lousy raw material to start with for cement production.  It has far to many impurities in it to be a part of the raw materials for making cement of usable quality.  These impurities cause the product made out of that cement to break down within only a few years of use.  If you want to start with coal as the energy source for making cement you have to make it into coke first to eliminate the impurities,  but that process wipes out the entire carbon capture rationale.  It's far easier just to start with natural gas as the fuel in the first place, and eliminate all the preparation steps while ensuring that that the CO2 emitted by the fuel is 1/2 as large in the first place.

Edited December 2, 2020 by Eric Gagen

[KeyboardWarrior + 527]

2 hours ago, Eric Gagen said:

There is plenty of coal and coal ash.  The main problem is that coal is a lousy raw material to start with for cement production.  It has far to many impurities in it to be a part of the raw materials for making cement of usable quality.  These impurities cause the product made out of that cement to break down within only a few years of use.  If you want to start with coal as the energy source for making cement you have to make it into coke first to eliminate the impurities,  but that process wipes out the entire carbon capture rationale.  It's far easier just to start with natural gas as the fuel in the first place, and eliminate all the preparation steps while ensuring that that the CO2 emitted by the fuel is 1/2 as large in the first place

They've been adding fly ash to cement for a while. Are you saying they purify the ash before doing so?

With briquettes of limestone and coal, there isn't going to be enough ash per briquette. Excess limestone will be present. 

How does coking the coal wipe out the capture rationale? That depends entirely on how the coke was prepared. 

Edited December 2, 2020 by KeyboardWarrior

[specinho + 470]

On 3/3/2020 at 11:38 PM, Richard D said:

Cement manufacture produces carbon dioxide from decomposition of calcium carbonate and also from the combustion of fuel that is burned to drive that endothermic decomposition.

It might be worth noticing also problems caused by the finished product itself......... For example, with sun ray, heat would be absorbed. The heated houses or buildings would need more energy to cool down. As night comes, energy released from cement walls into the environment and trapped among buildings could be so astounding that

1. it changes the direction or circulative patterns of sea breeze and land breeze;

2. changes microclimate of the area involved;

3. affects regular rain patterns and etc..............

[Eric Gagen + 713]

On 12/2/2020 at 10:42 AM, KeyboardWarrior said:

They've been adding fly ash to cement for a while. Are you saying they purify the ash before doing so?

With briquettes of limestone and coal, there isn't going to be enough ash per briquette. Excess limestone will be present. 

How does coking the coal wipe out the capture rationale? That depends entirely on how the coke was prepared. 

My comment about fly ash was with respect to quantity only.  There is plenty of it and the amount used for cement production is tiny compared to the amount available.  Storage and disposal of excess fly ash is a much larger problem than having enough of it to use in processes (like cement production) where it has the ability of adding value.  

Coal is the stuff that is a terrible raw material for cement production IF you are concerned about the environmental effects.  Coked or not (and to make cement it MUST be coked) coal is simply the wrong sort of raw material to start with if you are concerned in the slightest about carbon capture and removal.  Combustion of coal releases approximately twice as much CO2 per unit energy as the combustion of natural gas.  Any process which might be utilized to capture and remove the CO2 from the cement production process will cost half as much if you start with natural gas as the energy feedstock instead of coal.  The coking process is yet another unavoidable cost piled on top of coal which isn't present if you select natural gas as the primary energy feedstock for the process.  Coking is an expensive but necessary to remove volatile and combustible contaminants in coal. The most important for the production of cement are volatile sulfur compounds and naphthenic hydrocarbons.  If you are also going to capture the contaminants from this process then it gets even MORE costly. Natural gas doesn't have any impurities so you simply skip this step completely without any costs or environmental impacts.

The only advantage coal has (or used to have anyway) is low cost.  however that cost only stays low if you externalize and do not count ANY of the environmental effects of burning coal.  As soon as you try to do so,  coal is an obviously unsuitable starting point for use.  

[Richard D + 86]

If you object to the volatiles in coal,then it would be possible to use the vast dumps of high-ash anthracite culm in Pennsylvania. Carbon dioxide content of the exit gas would be at high partial pressure and could be removed by chilling,for enhanced oil recovery. Sulphur in the cement is no problem as in forms calcium aluminosulphate. Gypsum is added to cement for this purpose.